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Sample records for submodels large char

  1. CFD Simulation of Entrained Flow Gasification With Improved Devolatilization and Char Consumption Submodels

    KAUST Repository

    Kumar, Mayank

    2009-01-01

    In this work, we use a CFD package to model the operation of a coal gasifier with the objective of assessing the impact of devolatilization and char consumption models on the accuracy of the results. Devolatilization is modeled using the Chemical Percolation Devolitilization (CPD) model. The traditional CPD models predict the rate and the amount of volatiles released but not their species composition. We show that the knowledge of devolatilization rates is not sufficient for the accurate prediction of char consumption and a quantitative description of the devolatilization products, including the chemical composition of the tar, is needed. We incorporate experimental data on devolatilization products combined with modeling of the tar composition and reactions to improve the prediction of syngas compositions and carbon conversion. We also apply the shrinking core model and the random pore model to describe char consumption in the CFD simulations. Analysis of the results indicates distinct regimes of kinetic and diffusion control depending on the particle radius and injection conditions for both char oxidation and gasification reactions. The random pore model with Langmuir-Hinshelwood reaction kinetics are found to be better at predicting carbon conversion and exit syngas composition than the shrinking core model with Arrhenius kinetics. In addition, we gain qualitative and quantitative insights into the impact of the ash layer surrounding the char particle on the reaction rate. Copyright © 2010 by ASME.

  2. Inventory-based sensitivity analysis of the Large Tree Diameter Growth Submodel of the Southern Variant of the FVS

    Science.gov (United States)

    Giorgio Vacchiano; John D. Shaw; R. Justin DeRose; James N. Long

    2008-01-01

    Diameter increment is an important variable in modeling tree growth. Most facets of predicted tree development are dependent in part on diameter or diameter increment, the most commonly measured stand variable. The behavior of the Forest Vegetation Simulator (FVS) largely relies on the performance of the diameter increment model and the subsequent use of predicted dbh...

  3. UZ Flow Models and Submodels

    Energy Technology Data Exchange (ETDEWEB)

    Y. Wu

    2004-11-01

    The purpose of this report is to document the unsaturated zone (UZ) flow models and submodels, as well as the flow fields that have been generated using the UZ flow model(s) of Yucca Mountain, Nevada. In this report, the term ''UZ model'' refers to the UZ flow model and the several submodels, which include tracer transport, temperature or ambient geothermal, pneumatic or gas flow, and geochemistry (chloride, calcite, and strontium) submodels. The term UZ flow model refers to the three-dimensional models used for calibration and simulation of UZ flow fields. This work was planned in the ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.7). The table of included Features, Events, and Processes (FEPs), Table 6.2-11, is different from the list of included FEPs assigned to this report in the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Table 2.1.5-1), as discussed in Section 6.2.6. The UZ model has revised, updated, and enhanced the previous UZ model (BSC 2001 [DIRS 158726]) by incorporating the repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates, and their spatial distributions as well as moisture conditions in the UZ system. These three-dimensional UZ flow fields are used directly by Total System Performance Assessment (TSPA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test hypotheses of flow and transport at different scales, and predict flow and transport behavior under a variety of climatic conditions. In addition, the limitations of the UZ model are discussed in Section 8.11.

  4. UZ Flow Models and Submodels

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-02-11

    The purpose of this Model Report is to document the unsaturated zone (UZ) fluid flow and tracer transport models and submodels as well as the flow fields generated utilizing the UZ Flow and Transport Model of Yucca Mountain (UZ Model), Nevada. This work was planned in ''Technical Work Plan (TWP) for: Performance Assessment Unsaturated Zone'' (BSC 2002 [160819], Section 1.10, Work Package AUZM06). The UZ Model has revised, updated, and enhanced the previous UZ Flow Model REV 00 ICN 01 (BSC 2001 [158726]) by incorporation of the conceptual repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates and their spatial distributions as well as moisture conditions in the UZ system. These 3-D UZ flow fields are used directly by Performance Assessment (PA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic conditions. In addition, this Model Report supports several PA activities, including abstractions, particle-tracking transport simulations, and the UZ Radionuclide Transport Model.

  5. BPS submodels of the Skyrme model

    Energy Technology Data Exchange (ETDEWEB)

    Adam, C., E-mail: adam@fpaxp1.usc.es [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Sanchez-Guillen, J. [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Wereszczynski, A. [Institute of Physics, Jagiellonian University, Lojasiewicza 11, Kraków (Poland)

    2017-06-10

    We show that the standard Skyrme model without pion mass term can be expressed as a sum of two BPS submodels, i.e., of two models whose static field equations, independently, can be reduced to first order equations. Further, these first order (BPS) equations have nontrivial solutions, at least locally. These two submodels, however, cannot have common solutions. Our findings also shed some light on the rational map approximation. Finally, we consider certain generalisations of the BPS submodels.

  6. Technical Note: Coupling of chemical processes with the Modular Earth Submodel System (MESSy) submodel TRACER

    Science.gov (United States)

    Jöckel, P.; Kerkweg, A.; Buchholz-Dietsch, J.; Tost, H.; Sander, R.; Pozzer, A.

    2008-03-01

    The implementation of processes related to chemistry into Earth System Models and their coupling within such systems requires the consistent description of the chemical species involved. We provide a tool (written in Fortran95) to structure and manage information about constituents, hereinafter referred to as tracers, namely the Modular Earth Submodel System (MESSy) generic (i.e., infrastructure) submodel TRACER. With TRACER it is possible to define a multitude of tracer sets, depending on the spatio-temporal representation (i.e., the grid structure) of the model. The required information about a specific chemical species is split into the static meta-information about the characteristics of the species, and its (generally in time and space variable) abundance in the corresponding representation. TRACER moreover includes two submodels. One is TRACER_FAMILY, an implementation of the tracer family concept. It distinguishes between two types: type-1 families are usually applied to handle strongly related tracers (e.g., fast equilibrating species) for a specific process (e.g., advection). In contrast to this, type-2 families are applied for tagging techniques. Tagging means the artificial decomposition of one or more species into parts, which are additionally labelled (e.g., by the region of their primary emission) and then processed as the species itself. The type-2 family concept is designed to conserve the linear relationship between the family and its members. The second submodel is TRACER_PDEF, which corrects and budgets numerical negative overshoots that arise in many process implementations due to the numerical limitations (e.g., rounding errors). The submodel therefore guarantees the positive definiteness of the tracers and stabilises the integration scheme. As a by-product, it further provides a global tracer mass diagnostic. Last but not least, we present the submodel PTRAC, which allows the definition of tracers via a Fortran95 namelist, as a complement to

  7. Study on CO2 gasification reactivity and physical characteristics of biomass, petroleum coke and coal chars.

    Science.gov (United States)

    Huo, Wei; Zhou, Zhijie; Chen, Xueli; Dai, Zhenghua; Yu, Guangsuo

    2014-05-01

    Gasification reactivities of six different carbonaceous material chars with CO2 were determined by a Thermogravimetric Analyzer (TGA). Gasification reactivities of biomass chars are higher than those of coke and coal chars. In addition, physical structures and chemical components of these chars were systematically tested. It is found that the crystalline structure is an important factor to evaluate gasification reactivities of different chars and the crystalline structures of biomass chars are less order than those of coke and coal chars. Moreover, initial gasification rates of these chars were measured at high temperatures and with relatively large particle sizes. The method of calculating the effectiveness factor η was used to quantify the effect of pore diffusion on gasification. The results show that differences in pore diffusion effects among gasification with various chars are prominent and can be attributed to different intrinsic gasification reactivities and physical characteristics of different chars. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Effect of pyrolysis conditions and composition on the char structure and char yield of biomass chars

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Steibel, Markus; Spliethoff, Hartmut

    The char yield as well as physical and chemical structure of chars generated from different types of biomass divided into five different particle size fractions from 50μm to 1mm were studied to better understand the influences of holding time, final temperatures and heating rates on the pyrolysis...... characteristics of biomass chars. An additional study of the char phase-organic transformation was conducted on the biomass organic matter. Char samples were generated in a wire-mesh reactor up to 1400°C, and with the heating rates between 10 K/s and 3000 K/s. The results were compared with the data gained from...... electron microscopy indicated different types of softening and melting of the biomass chars at all applied temperatures, heating rates and holding times, except for rice husks, which formed chars with a structure similar to the parent fuel. The char particles generated at high pyrolysis temperatures had...

  9. Modelling the charring behaviour of structural lumber

    Science.gov (United States)

    Peter W.C. Lau; Robert White; Ineke Van Zealand

    1999-01-01

    Charring rates for large-section timber based on experimental data have been generally established. The established rates may not be appropriately used for the prediction of failure times of lumber members which are small by comparison. It is questionable whether a constant rate can be safely assumed for lumber members since the rate is likely to increase once the...

  10. Technical Note: Anthropogenic and natural offline emissions and the online EMissions and dry DEPosition submodel EMDEP of the Modular Earth Submodel system (MESSy)

    NARCIS (Netherlands)

    Ganzeveld, L.N.; Aardenne, van J.A.; Butler, T.M.; Lawrence, M.G.; Metzger, S.M.; Stier, P.; Zimmermann, P.; Lelieveld, J.

    2006-01-01

    We present the online calculated Earth's surface trace gas and aerosol emissions and dry deposition in the Modular Earth Submodel System (MESSy) submodel EMDEP as well as the currently applied anthropogenic and natural emissions inventories. These inventories, being read-in by the MESSy submodel

  11. On the sub-model errors of a generalized one-way coupling scheme for linking models at different scales

    Science.gov (United States)

    Zeng, Jicai; Zha, Yuanyuan; Zhang, Yonggen; Shi, Liangsheng; Zhu, Yan; Yang, Jinzhong

    2017-11-01

    Multi-scale modeling of the localized groundwater flow problems in a large-scale aquifer has been extensively investigated under the context of cost-benefit controversy. An alternative is to couple the parent and child models with different spatial and temporal scales, which may result in non-trivial sub-model errors in the local areas of interest. Basically, such errors in the child models originate from the deficiency in the coupling methods, as well as from the inadequacy in the spatial and temporal discretizations of the parent and child models. In this study, we investigate the sub-model errors within a generalized one-way coupling scheme given its numerical stability and efficiency, which enables more flexibility in choosing sub-models. To couple the models at different scales, the head solution at parent scale is delivered downward onto the child boundary nodes by means of the spatial and temporal head interpolation approaches. The efficiency of the coupling model is improved either by refining the grid or time step size in the parent and child models, or by carefully locating the sub-model boundary nodes. The temporal truncation errors in the sub-models can be significantly reduced by the adaptive local time-stepping scheme. The generalized one-way coupling scheme is promising to handle the multi-scale groundwater flow problems with complex stresses and heterogeneity.

  12. Bolted Ribs Analysis for the ITER Vacuum Vessel using Finite Element Submodelling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zarzalejos, José María, E-mail: jose.zarzalejos@ext.f4e.europa.eu [External at F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Fernández, Elena; Caixas, Joan; Bayón, Angel [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Polo, Joaquín [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Guirao, Julio [Numerical Analysis Technologies, S L., Marqués de San Esteban 52, Entlo, 33209 Gijon (Spain); García Cid, Javier [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Rodríguez, Eduardo [Mechanical Engineering Department EPSIG, University of Oviedo, Gijon (Spain)

    2014-10-15

    Highlights: • The ITER Vacuum Vessel Bolted Ribs assemblies are modelled using Finite Elements. • Finite Element submodelling techniques are used. • Stress results are obtained for all the assemblies and a post-processing is performed. • All the elements of the assemblies are compliant with the regulatory provisions. • Submodelling is a time-efficient solution to verify the structural integrity of this type of structures. - Abstract: The ITER Vacuum Vessel (VV) primary function is to enclose the plasmas produced by the ITER Tokamak. Since it acts as the first radiological barrier of the plasma, it is classified as a class 2 welded box structure, according to RCC-MR 2007. The VV is made of an inner and an outer D-shape, 60 mm-thick double shell connected through thick massive bars (housings) and toroidal and poloidal structural stiffening ribs. In order to provide neutronic shielding to the ex-vessel components, the space between shells is filled with borated steel plates, called In-Wall Shielding (IWS) blocks, and water. In general, these blocks are connected to the IWS ribs which are connected to adjacent housings. The development of a Finite Element model of the ITER VV including all its components in detail is unaffordable from the computational point of view due to the large number of degrees of freedom it would require. This limitation can be overcome by using submodelling techniques to simulate the behaviour of the bolted ribs assemblies. Submodelling is a Finite Element technique which allows getting more accurate results in a given region of a coarse model by generating an independent, finer model of the region under study. In this paper, the methodology and several simulations of the VV bolted ribs assemblies using submodelling techniques are presented. A stress assessment has been performed for the elements involved in the assembly considering possible types of failure and including stress classification and categorization techniques to analyse

  13. Overview of the CHarring Ablator Response (CHAR) Code

    Science.gov (United States)

    Amar, Adam J.; Oliver, A. Brandon; Kirk, Benjamin S.; Salazar, Giovanni; Droba, Justin

    2016-01-01

    An overview of the capabilities of the CHarring Ablator Response (CHAR) code is presented. CHAR is a one-, two-, and three-dimensional unstructured continuous Galerkin finite-element heat conduction and ablation solver with both direct and inverse modes. Additionally, CHAR includes a coupled linear thermoelastic solver for determination of internal stresses induced from the temperature field and surface loading. Background on the development process, governing equations, material models, discretization techniques, and numerical methods is provided. Special focus is put on the available boundary conditions including thermochemical ablation and contact interfaces, and example simulations are included. Finally, a discussion of ongoing development efforts is presented.

  14. Investigation of the submodels for combustion; Polton osamallien kaeytettaevyys

    Energy Technology Data Exchange (ETDEWEB)

    Kjaeldman, L.; Huttunen, M.; Kyttaelae, J. [VTT Energy, Espoo (Finland)

    1997-10-01

    The capability for numerical analysis of flow, combustion and heat transfer in furnaces has been developed by improving the knowledge of the sensitivity of computed results on submodels recently implemented to the computational environment Ardemus owned by VTT Energy and Imatran Voima Oy. The submodels studied include models for combustion of gaseous (pyrolysed) fuel and for nitric oxide. The cases investigated included a gas flame and pulverized coal and peat combustion in single burner furnaces. The effect of grid refinement on the results was investigated for a corner fired power station furnace. (orig.)

  15. Investigation of char morphology using image analysis

    Energy Technology Data Exchange (ETDEWEB)

    T. Wu; M. Cloke; R. Barranco; E. Lester [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre

    2003-07-01

    The aim of this work is to identify methods for describing char morphology, using image analysis, which could be included in a burnout model. Char samples from four coals, Bijao, El Cerrejon, Caypa and Ashland, were used in this study. Chars were prepared from the coals using a drop-tube furnace and the chars mounted in resin for investigation and image-analysis using reflected light microscopy. A number of image-analysis techniques were developed in order to separate touching char particles, reconstruct fragmented char particles and measure char wall thickness, char and particle areas and char particle size. These methods were then tested on chars from the above coals. It was found that the algorithm developed for rebuilding char walls works well in selecting all possible fragments to rebuild a whole char particle using the 'Close' function. It was shown that close with the structural element shape 6 was the optimum when using the image analysis software in this study, the KS 400 image-analysis system. This algorithm was combined with others to give a new image analysis technique in the investigation of char morphology. It was shown that the technique is capable of characterizing char automatically and produces char morphological data, which could be included in char burnout models. 11 refs., 6 figs., 6 tabs.

  16. The generic MESSy submodel TENDENCY (v1.0 for process-based analyses in Earth system models

    Directory of Open Access Journals (Sweden)

    R. Eichinger

    2014-07-01

    processes (large-scale clouds, convective clouds, large-scale advection, vertical diffusion and methane oxidation show that the upward propagating water vapour signal dissolves mainly because of the chemical and the advective contribution. The TENDENCY submodel is part of version 2.42 or later of MESSy.

  17. Study on CO₂ gasification properties and kinetics of biomass chars and anthracite char.

    Science.gov (United States)

    Wang, Guangwei; Zhang, Jianliang; Hou, Xinmei; Shao, Jiugang; Geng, Weiwei

    2015-02-01

    The CO2 gasification properties and kinetics of three biomass chars (WS-char, RL-char and PS-char) and anthracite char (AC-char) were investigated by thermogravimetric analysis method. Three nth-order representative gas-solid reaction models, random pore model (RPM), volume reaction model (VM) and unreacted core model (URCM) were employed to describe the reactive behavior of chars. Results show that gasification reactivity order of different chars from high to low was WS-char, PS-char, RL-char and AC-char. In addition, the chemical components as well as physical structures of four chars were systematically tested. It was found that gasification properties of char were determined by carbonaceous structure. It was concluded from kinetics analysis that RPM model was the best model for describing the reactivities of biomass chars and VM was the model that best fitted the gasification process of anthracite char. The activation energies obtained for the biomass and anthracite char samples lie in the range of 236.4-284.9 kJ/mol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Contribution of emissions to concentrations: the TAGGING 1.0 submodel based on the Modular Earth Submodel System (MESSy 2.52

    Directory of Open Access Journals (Sweden)

    V. Grewe

    2017-07-01

    (mainly emission sectors to, e.g., ozone, are only marginally sensitive to changes in model resolution, though the level of detail increases. A reduction in road traffic emissions by 5 % shows that road traffic global tropospheric ozone is reduced by 4 % only, because the net ozone productivity increases. This 4 % reduction in road traffic tropospheric ozone corresponds to a reduction in total tropospheric ozone by  ≈  0.3 %, which is compensated by an increase in tropospheric ozone from other sources by 0.1 %, resulting in a reduction in total tropospheric ozone of  ≈  0.2 %. This compensating effect compares well with previous findings. The computational costs of the TAGGING submodel are low with respect to computing time, but a large number of additional tracers are required. The advantage of the tagging scheme is that in one simulation and at every time step and grid point, information is available on the contribution of different emission sectors to the ozone budget, which then can be further used in upcoming studies to calculate the respective radiative forcing simultaneously.

  19. Contribution of emissions to concentrations: the TAGGING 1.0 submodel based on the Modular Earth Submodel System (MESSy 2.52)

    Science.gov (United States)

    Grewe, Volker; Tsati, Eleni; Mertens, Mariano; Frömming, Christine; Jöckel, Patrick

    2017-07-01

    sectors) to, e.g., ozone, are only marginally sensitive to changes in model resolution, though the level of detail increases. A reduction in road traffic emissions by 5 % shows that road traffic global tropospheric ozone is reduced by 4 % only, because the net ozone productivity increases. This 4 % reduction in road traffic tropospheric ozone corresponds to a reduction in total tropospheric ozone by ≈ 0.3 %, which is compensated by an increase in tropospheric ozone from other sources by 0.1 %, resulting in a reduction in total tropospheric ozone of ≈ 0.2 %. This compensating effect compares well with previous findings. The computational costs of the TAGGING submodel are low with respect to computing time, but a large number of additional tracers are required. The advantage of the tagging scheme is that in one simulation and at every time step and grid point, information is available on the contribution of different emission sectors to the ozone budget, which then can be further used in upcoming studies to calculate the respective radiative forcing simultaneously.

  20. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

    Energy Technology Data Exchange (ETDEWEB)

    E. Cetin; R. Gupta; B. Moghtaderi [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2005-07-01

    The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000{degree}C, and heating rates between 20 and 500{degree}C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. 22 refs., 8 figs., 2 tabs.

  1. Char binder for fluidized beds

    Science.gov (United States)

    Borio, Richard W.; Accortt, Joseph I.

    1981-01-01

    An arrangement that utilizes agglomerating coal as a binder to bond coal fines and recycled char into an agglomerate mass that will have suitable retention time when introduced into a fluidized bed 14 for combustion. The simultaneous use of coal for a primary fuel and as a binder effects significant savings in the elimination of non-essential materials and processing steps.

  2. Simulation of polar stratospheric clouds in the chemistry-climate-model EMAC via the submodel PSC

    Directory of Open Access Journals (Sweden)

    O. Kirner

    2011-03-01

    Full Text Available The submodel PSC of the ECHAM5/MESSy Atmospheric Chemistry model (EMAC has been developed to simulate the main types of polar stratospheric clouds (PSC. The parameterisation of the supercooled ternary solutions (STS, type 1b PSC in the submodel is based on Carslaw et al. (1995b, the thermodynamic approach to simulate ice particles (type 2 PSC on Marti and Mauersberger (1993. For the formation of nitric acid trihydrate (NAT particles (type 1a PSC two different parameterisations exist. The first is based on an instantaneous thermodynamic approach from Hanson and Mauersberger (1988, the second is new implemented and considers the growth of the NAT particles with the aid of a surface growth factor based on Carslaw et al. (2002. It is possible to choose one of this NAT parameterisation in the submodel. This publication explains the background of the submodel PSC and the use of the submodel with the goal of simulating realistic PSC in EMAC.

  3. Studies on biomass char gasification and dynamics

    Science.gov (United States)

    You, Zhanping; You, Shijun; Ma, Xiaoyan

    2018-01-01

    The gasification performances of two kinds of biomass char by experiment methods are studied, including conversion rate and gasification gas component with temperature and time. Experimental results show that gasification temperature has important effects on the conversion rate and gas component. In the range of experimental temperature, char conversion rates are no more than 30.0%. The apparent activation energies and apparent reaction frequency factors of two biomass chars are obtained through kinetic studies.

  4. Reaction characteristics of chars formed by one-stage and two-stage entrained-flow gasification

    Energy Technology Data Exchange (ETDEWEB)

    Harada, E.; Kumada, N.; Morishita, Y.; Sakata, Y. [Kawasaki Heavy Industrial Co. Ltd., Hyogo (Japan). Technical Institute

    2004-09-01

    To compare the chars formed by one-stage and two-stage gasification in an entrained-flow coal-gasifier, the gasification method of entrained-flow-coal-gasifier, gasification tests were carried out using a practical gasifier with a capacity of 25 t/d coal input, in which both operations were possible. Gasification reaction characteristics of the chars formed at high temperature and pressure were examined by thermogravimetric analysis. As the result, the following characteristics were clarified. 1) The gasification rate of the char formed in the one-stage gasification at high temperature condition is lower than that of the char formed in two-stage gasification, which combined high-temperature and low-temperature operations. 2) The char formed in the two-stage gasification is a mixture of small particles formed at high temperature in the first stage and large particles formed at low temperature in the second stage. The gasification reaction of the char progresses in two steps, as such that both types of particle were synthesized. 3) The gasification rate of small particles within the char formed in two-stage gasification is lower than that of large particles within the same char and showed a similar value to that of the char formed in one-stage gasification.

  5. Defluoridation with Locally Produced Thai Bone Char

    Directory of Open Access Journals (Sweden)

    Yothin Mutchimadilok

    2014-01-01

    Full Text Available The fluoride sorption ability of a locally available bone char is quantified. Both a synthetic solution and natural groundwater samples from several sites are studied and compared to Indian bone char, which is widely accepted and used successfully in India and elsewhere. The Freundlich and Langmuir sorption isotherms were used to quantify sorption properties. Results show that the Thai bone char is as effective as the Indian bone char for removing fluoride from contaminated water, despite the more rigid physical and social constraints found in rural Thailand. Sorption studies with fluoride-contaminated natural groundwater samples also show that chlorides, nitrates, and sulfates had little effect on the removal of fluoride by the homemade bone char.

  6. Feasibility of mercury removal from simulated flue gas by activated chars made from poultry manures

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.; Lima, I.M.; Boihem, L.L.; Wartelle, L.H. [USDA, New Orleans, LA (United States)

    2010-12-15

    Increased emphasis on reduction of mercury emissions from coal fired electric power plants has resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents for mercury removal. At the same time, the quantity of poultry manure generated each year is large and technologies that take advantage of the material should be explored. The purpose of the work was to obtain preliminary data to investigate if activated chars made from different poultry manures could adsorb mercury from simulated flue gas. In laboratory experiments, activated chars made from chicken cake and litter removed mercury from the gas as well as a commercial alternative. It was also found that acid-washing these chars after activation may improve pore structure but does not influence the mercury removal efficiency. Activated chars were also made from turkey cake and litter. These raw materials produced activated chars with similar pore structure as those made from chicken manure, but they did not adsorb mercury as well. Acid-washing the turkey manure-based chars improved their performance, but this step would add to the cost of production. Preliminary evaluations suggest that unwashed activated chars may cost as little as $0.95/kg to produce.

  7. Feasibility of mercury removal from simulated flue gas by activated chars made from poultry manures.

    Science.gov (United States)

    Klasson, K Thomas; Lima, Isabel M; Boihem, Larry L; Wartelle, Lynda H

    2010-12-01

    Increased emphasis on reduction of mercury emissions from coal fired electric power plants has resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents for mercury removal. At the same time, the quantity of poultry manure generated each year is large and technologies that take advantage of the material should be explored. The purpose of the work was to obtain preliminary data to investigate if activated chars made from different poultry manures could adsorb mercury from simulated flue gas. In laboratory experiments, activated chars made from chicken cake and litter removed mercury from the gas as well as a commercial alternative. It was also found that acid-washing these chars after activation may improve pore structure but does not influence the mercury removal efficiency. Activated chars were also made from turkey cake and litter. These raw materials produced activated chars with similar pore structure as those made from chicken manure, but they did not adsorb mercury as well. Acid-washing the turkey manure-based chars improved their performance, but this step would add to the cost of production. Preliminary evaluations suggest that unwashed activated chars may cost as little as $0.95/kg to produce. Published by Elsevier Ltd.

  8. Combustion of char from plastic wastes pyrolysis

    Science.gov (United States)

    Saptoadi, Harwin; Rohmat, Tri Agung; Sutoyo

    2016-06-01

    A popular method to recycle plastic wastes is pyrolysis, where oil, gas and char can be produced. These products can be utilized as fuels because they are basically hydrocarbons. The research investigates char properties, including their performance as fuel briquettes. There are 13 char samples from PE (Polyethylene) pyrolyzed at temperatures of around 450 °C, with and without a catalyst. Some of the samples were obtained from PE mixed with other types, such as Polystyrene (PS), Polypropylene (PP), Polyethylene Terephthalate (PET), and Others. Char properties, such as moisture, ash, volatile matter, and fixed carbon contents, are revealed from the proximate analysis, whereas calorific values were measured with a bomb calorimeter. Briquettes are made by mixing 4 g of char with 0.5 - 1 g binder. Briquettes are hollow cylinders with an outer and inner diameter of around 1.75 cm and 0.25 cm, respectively. Combustion is carried out in a furnace with wall temperatures of about 230°C and a constant air velocity of 0.7 m/s. Five out of 13 char briquettes are not feasible because they melt during combustion. Briquettes made from 100% PE wastes burn in substantially shorter duration than those from mixed plastic wastes. Char #1 and #5 are excellent due to their highest energy release, whereas #10 show the worst performance.

  9. Model for biomass char combustion in the riser of a dual fluidized bed gasification unit: Part 1 - model development and sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kaushal, Priyanka; Proell, Tobias; Hofbauer, Hermann [Vienna University of Technology, Institute of Chemical Engineering, Getreidemarkt 9/166, A-1060, Vienna (Austria)

    2008-07-15

    A comprehensive model for steady state combustion of biomass char in a fast fluidized bed is presented, although the model is capable to deal any fluidization regime. The air needed for combustion is staged as bottom, primary and secondary air. The combustor is divided into two sectors: a dense (bottom) zone and a transport (upper) zone. The model consists of sub-models for bed hydrodynamics, conversion and conservation. The hydrodynamic description of the bottom bed is based on the modified two phase theory while the freeboard is based on a simplified core-annulus approach. Biomass char is modelled as partially volatile fuel. Char composition is a model parameter and is defined by weight fractions of C, H and O. The model includes the release of volatiles from biomass char and their subsequent combustion. The combustion reactor also serves as a sink for spent organic solvent. Char mass balance and energy balances are solved globally in each zone. The sensitivity analysis shows that the model is not very sensitive to changes in operating parameters. The model is robust to deal with solid, liquid and gaseous fuel combustion. (author)

  10. Early resin luting material damage around a circular fiber post in a root canal treated premolar by using micro-computerized tomographic and finite element sub-modeling analyses.

    Science.gov (United States)

    Chang, Yen-Hsiang; Lee, Hao; Lin, Chun-Li

    2015-11-01

    This study utilizes micro-computerized tomographic (micro-CT) and finite element (FE) sub-modeling analyses to investigate the micro-mechanical behavior associated with voids/bubbles stress behavior at the luting material layer to understand the early damage in a root canal treated premolar. 3-dimensional finite element (FE) models of a macro-root canal treated premolar and two sub-models at the luting material layer to provide the void/bubble distribution and dimensions were constructed from micro-CT images and simulated to receive axial and lateral forces. The boundary conditions for the sub-models were determined from the macro-premolar model results and applied in sub-modeling analysis. The first principal stresses for the dentin, luting material layer and post in macro-premolar model and for luting material void/bubble in sub-models were recorded. The simulated results revealed that the macro-premolar model dramatically underestimated the luting material stress because the voids/bubbles at the adhesive layer cannot be captured due to coarse mesh and high stress gradient and the variations between sub- and macro-models ranging from 2.65 to 4.5 folds under lateral load at the mapping location. Stress concentrations were found at the edge of the voids/bubbles and values over 20 MPa in sub-modeling analysis immediately caused the luting material failure/micro-crack. This study establishes that micro-CT and FE sub-modeling techniques can be used to simulate the stress pattern at the micro-scale luting material layer in a root canal treated premolar, suggesting that attention must be paid to resin luting material initial failure/debonding when large voids/bubbles are generated during luting procedures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Improved accuracy in quantitative laser-induced breakdown spectroscopy using sub-models

    Science.gov (United States)

    Anderson, Ryan B.; Clegg, Samuel M.; Frydenvang, Jens; Wiens, Roger C.; McLennan, Scott; Morris, Richard V.; Ehlmann, Bethany; Dyar, M. Darby

    2017-03-01

    Accurate quantitative analysis of diverse geologic materials is one of the primary challenges faced by the laser-induced breakdown spectroscopy (LIBS)-based ChemCam instrument on the Mars Science Laboratory (MSL) rover. The SuperCam instrument on the Mars 2020 rover, as well as other LIBS instruments developed for geochemical analysis on Earth or other planets, will face the same challenge. Consequently, part of the ChemCam science team has focused on the development of improved multivariate analysis calibrations methods. Developing a single regression model capable of accurately determining the composition of very different target materials is difficult because the response of an element's emission lines in LIBS spectra can vary with the concentration of other elements. We demonstrate a conceptually simple "sub-model" method for improving the accuracy of quantitative LIBS analysis of diverse target materials. The method is based on training several regression models on sets of targets with limited composition ranges and then "blending" these "sub-models" into a single final result. Tests of the sub-model method show improvement in test set root mean squared error of prediction (RMSEP) for almost all cases. The sub-model method, using partial least squares (PLS) regression, is being used as part of the current ChemCam quantitative calibration, but the sub-model method is applicable to any multivariate regression method and may yield similar improvements.

  12. Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

    DEFF Research Database (Denmark)

    Álvarez, L.; Yin, Chungen; Riaza, J.

    2013-01-01

    The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation....... In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were...... implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21-35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results...

  13. Model development and validation: Co-combustion of residual char, gases and volatile fuels in the fast fluidized combustion chamber of a dual fluidized bed biomass gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Priyanka Kaushal; Tobias Proell; Hermann Hofbauer [Vienna University of Technology, Vienna (Austria). Institute of Chemical Engineering

    2007-12-15

    A one-dimensional steady state model has been developed for the combustion reactor of a dual fluidized bed biomass steam gasification system. The combustion reactor is operated as fast fluidized bed (riser) with staged air introduction (bottom, primary and secondary air). The main fuel i.e., residual biomass char (from the gasifier), is introduced together with the circulating bed material at the bottom of the riser. The riser is divided into two zones: bottom zone (modelled according to modified two phase theory) and upper zone (modelled with core-annulus approach). The model consists of sub-model for bed hydrodynamic, conversion and conservation. Biomass char is assumed to be a homogeneous matrix of C, H and O and is modelled as partially volatile fuel. The exit gas composition and the temperature profile predicted by the model are in good agreement with the measured value. 34 refs., 8 figs., 3 tabs.

  14. Active sites in char gasification: Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Wojtowicz, M.; Lilly, W.D.; Perkins, M.T.; Hradil, G.; Calo, J.M.; Suuberg, E.M.

    1987-09-01

    Among the key variables in the design of gasifiers and combustors is the reactivity of the chars which must be gasified or combusted. Significant loss of unburned char is unacceptable in virtually any process; the provision of sufficient residence time for complete conversion is essential. A very wide range of reactivities are observed, depending upon the nature of the char in a process. The current work focuses on furthering the understanding of gasification reactivities of chars. It has been well established that the reactivity of char to gasification generally depends upon three principal factors: (1) the concentration of ''active sites'' in the char; (2) mass transfer within the char; and (3) the type and concentration of catalytic impurities in the char. The present study primarily addresses the first factor. The subject of this research is the origin, nature, and fate of active sites in chars derived from parent hydrocarbons with coal-like structure. The nature and number of the active sites and their reactivity towards oxygen are examined in ''model'' chars derived from phenol-formaldehyde type resins. How the active sites are lost by the process of thermal annealing during heat treatment of chars are studied, and actual rate for the annealing process is derived. Since intrinsic char reactivities are of primary interest in the present study, a fair amount of attention was given to the model char synthesis and handling so that the effect of catalytic impurities and oxygen-containing functional groups in the chemical structure of the material were minimized, if not completely eliminated. The project would not be considered complete without comparing characteristic features of synthetic chars with kinetic behavior exhibited by natural chars, including coal chars.

  15. Relation between the petrographic composition of coal and the morphology of pyrolysis char produced in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    B. Valentim; M.J. Lemos de Sousa; P. Abelha; D. Boavida; I. Gulyurtlu [Centro de Geologia da Universidade do Porto, Porto (Portugal)

    2004-06-01

    Several previous studies have already established, for pulverized coal combustion conditions, global correlations between petrographic composition of the coal and those of char produced from the same coal. However, for fluidized bed combustion, there has not been much new work since the eighties. The results presented in this paper include the petrographic characterization of seven different coals from several origins and also of their respective chars produced at 700, 800, 900, and 1000{sup o}C in a laboratory fluidized bed reactor. The results show a marked predominance of tenuispheres as the trial temperatures increase. While vitrinite-rich coals essentially produced highly porous chars, the inertinite-rich coals produced large amounts of medium- and low-porous chars. Semi-anthracite vitrinite produced high-porous chars and thermal affected coal particles originated low-porous and angular char morphotypes. The analysis of the data obtained revealed that vitrinite + liptinite related well with the high-porous char (sum of cenospheres and tenuinetworks), classified as Group 1. The same trend, but with a weaker relation, was also observed between vitrinite and liptinite rich microlithotypes and Group 1. 32 refs., 17 refs., 3 tabs.

  16. Incineration of water pollutants with activated char from coal, wood, or crop residues in a system designed to produce energy and pyrolysis by-product chemicals. Final Technical completion report (Final)

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, S.E.; Gale, R.W.; Laquer, F.C.; Smith, K.E.; Bornhop, D.J.

    1982-11-18

    A wastewater-treatment system, particularly useful for treating chemical leachates, was developed on a laboratory scale. Subbituminous coal, 20-60-mesh, was pyrolyzed. A synthetic wastewater containing 3520 ppm total organic carbon was contacted with nonactivated char, char activated in water-saturated nitrogen at 850/sup 0/C, and coal ash. During a contact time of 0.5 hour, organic removals from the wastewater were 13.3% by nonactivated char, 38.8% by activated char, and 46.5% by ash. For a contact time of 72 hours, organic removals were about 25% for nonactivated char, 58.8% for activated char, and 53.4% for ash. This treatment system is applicable where large amounts of waste carbonaceous material (coal, wood, crop residues) are available. The spent char can be incinerated. Heat from incineration can be used in the pyrolysis step, and the coal ash can be recycled to the water-purification step.

  17. Kinetic Analysis of Char Thermal Deactivation

    DEFF Research Database (Denmark)

    Zolin, Alfredo; Jensen, Anker; Dam-Johansen, Kim

    2001-01-01

    . Leached straw deactivates significantly, but maintains at any heat-treatment temperature a higher reactivity than the other chars. The inertinite-rich coal Blair Athol is more resistant to deactivation than two vitrinite-rich coals of the same ASTM rank, Cerrejon and Illinois no. 6. Cerrejon and Illinois...

  18. Phosphorus recovery from sewage sludge char ash

    NARCIS (Netherlands)

    Atienza-Martinez, M.; Gea, G.; Arauzo, J.; Kersten, Sascha R.A.; Kootstra, A.M.J.

    2014-01-01

    Phosphorus was recovered from the ash obtained after combustion at different temperatures (600 °C, 750 °C and 900 °C) and after gasification (at 820 °C using a mixture of air and steam as fluidising agent) of char from sewage sludge fast pyrolysis carried out at 530 °C. Depending on the leaching

  19. The econometric submodels of the Energy Policy Socioeconomic Impact Model (EPSIM)

    Energy Technology Data Exchange (ETDEWEB)

    Butler, J.G.; Poyer, D.A.

    1994-04-01

    The Energy Policy Socioeconomic Impact Model (EPSIM) is an econometric simulation model that runs on IBM-compatible personal computers. It can be used to assess the economic impact of energy policies and programs, such as utility rate designs and demand-side management programs, on various population groups, such as minority and low-income households. The econometric submodels that constitute the internal structure of EPSIM are described in detail.

  20. Description and evaluation of GMXe: a new aerosol submodel for global simulations (v1

    Directory of Open Access Journals (Sweden)

    K. J. Pringle

    2010-09-01

    Full Text Available We present a new aerosol microphysics and gas aerosol partitioning submodel (Global Modal-aerosol eXtension, GMXe implemented within the ECHAM/MESSy Atmospheric Chemistry model (EMAC, version 1.8. The submodel is computationally efficient and is suitable for medium to long term simulations with global and regional models. The aerosol size distribution is treated using 7 log-normal modes and has the same microphysical core as the M7 submodel (Vignati et al., 2004.

    The main developments in this work are: (i the extension of the aerosol emission routines and the M7 microphysics, so that an increased (and variable number of aerosol species can be treated (new species include sodium and chloride, and potentially magnesium, calcium, and potassium, (ii the coupling of the aerosol microphysics to a choice of treatments of gas/aerosol partitioning to allow the treatment of semi-volatile aerosol, and, (iii the implementation and evaluation of the developed submodel within the EMAC model of atmospheric chemistry.

    Simulated concentrations of black carbon, particulate organic matter, dust, sea spray, sulfate and ammonium aerosol are shown to be in good agreement with observations (for all species at least 40% of modeled values are within a factor of 2 of the observations. The distribution of nitrate aerosol is compared to observations in both clean and polluted regions. Concentrations in polluted continental regions are simulated quite well, but there is a general tendency to overestimate nitrate, particularly in coastal regions (geometric mean of modelled values/geometric mean of observed data ≈2. In all regions considered more than 40% of nitrate concentrations are within a factor of two of the observations. Marine nitrate concentrations are well captured with 96% of modeled values within a factor of 2 of the observations.

  1. Interaction and its induced inhibiting or synergistic effects during co-gasification of coal char and biomass char.

    Science.gov (United States)

    Ding, Liang; Zhang, Yongqi; Wang, Zhiqing; Huang, Jiejie; Fang, Yitian

    2014-12-01

    Co-gasification of coal char and biomass char was conducted to investigate the interactions between them. And random pore model (RPM) and modified random pore model (MRPM) were applied to describe the gasification behaviors of the samples. The results show that inhibiting effect was observed during co-gasification of corn stalk char with Hulunbeier lignite coal char, while synergistic effects were observed during co-gasification of corn stalk char with Shenmu bituminous coal char and Jincheng anthracite coal char. The inhibiting effect was attributed to the intimate contact and comparable gasification rate between biomass char and coal char, and the loss of the active form of potassium caused by the formation of KAlSiO4, which was proved to be inactive during gasification. While the synergistic effect was caused by the high potassium content of biomass char and the significant difference of reaction rate between coal char and biomass char during gasification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Improved accuracy in quantitative laser-induced breakdown spectroscopy using sub-models

    Science.gov (United States)

    Anderson, Ryan; Clegg, Samuel M.; Frydenvang, Jens; Wiens, Roger C.; McLennan, Scott M.; Morris, Richard V.; Ehlmann, Bethany L.; Dyar, M. Darby

    2017-01-01

    Accurate quantitative analysis of diverse geologic materials is one of the primary challenges faced by the Laser-Induced Breakdown Spectroscopy (LIBS)-based ChemCam instrument on the Mars Science Laboratory (MSL) rover. The SuperCam instrument on the Mars 2020 rover, as well as other LIBS instruments developed for geochemical analysis on Earth or other planets, will face the same challenge. Consequently, part of the ChemCam science team has focused on the development of improved multivariate analysis calibrations methods. Developing a single regression model capable of accurately determining the composition of very different target materials is difficult because the response of an element’s emission lines in LIBS spectra can vary with the concentration of other elements. We demonstrate a conceptually simple “sub-model” method for improving the accuracy of quantitative LIBS analysis of diverse target materials. The method is based on training several regression models on sets of targets with limited composition ranges and then “blending” these “sub-models” into a single final result. Tests of the sub-model method show improvement in test set root mean squared error of prediction (RMSEP) for almost all cases. The sub-model method, using partial least squares regression (PLS), is being used as part of the current ChemCam quantitative calibration, but the sub-model method is applicable to any multivariate regression method and may yield similar improvements.

  3. Experimental Investigation of NO from Pulverized Char Combustion

    DEFF Research Database (Denmark)

    Jensen, Lars Skaarup; Jannerup, Hans Erik; Glarborg, Peter

    2001-01-01

    NO formation and reduction during pulverized char combustion in the temperature range 850–1150°C have been investigated in fixed-bed combustion experiments. Chars from a high-volatile bituminous coal and an anthracite have been used. Under single-particle conditions the selectivity for NO formation......-particle conditions, net NO formation is significantly lower due to NO reduction taking place simultaneously with NO formation. Rate expressions for NO reduction on char both in the presence and in the absence of O2 have been determined. For bituminous coal char, these rates are 10–100 times more rapid than values...... previously reported in literature, but are consistent with reburn-type experiments employing char as fuel. This discrepancy is mainly attributed to rapid char deactivation prior to measuring of NO reduction rates in previous determinations. Shortly after pyrolysis, the effective NO-char reaction rate...

  4. The infrastructure MESSy submodels GRID (v1.0) and IMPORT (v1.0)

    Science.gov (United States)

    Kerkweg, A.; Jöckel, P.

    2015-10-01

    The coupling of Earth system model components, which work on different grids, into an Earth System Model (ESM) provokes the necessity to transfer data from one grid to another. Additionally, each of these model components might require data import onto its specific grid. Usually, one of two approaches is used: Either all input data is preprocessed to the employed grid, or the imported data is interpolated on-line, i.e. during model integration to the required grid. For the former, each change in the model resolution requires the re-preprocessing of all data. The latter option implies that in each model integration computing time is required for the grid mapping. If all components of an ESM use only one single point of import and the same mapping software, only one software package needs to be changed for code optimisation, inclusion of additional interpolation methods or the implementation of new data formats. As the Modular Earth Submodel System (MESSy) is mainly used for research purposes which require frequent changes of the model setup including the model resolution or the application of different sets of input data (e.g., different emission scenarios), the idea of a common procedure for data import was implemented in MESSy in form of the infrastructure submodel IMPORT. Currently, IMPORT consists of two submodels: IMPORT_TS for reading and processing abstract time series data and IMPORT_GRID, utilising the infrastructure submodel GRID which provides procedures for grid transformations using the remapping software packages NREGRID (Jöckel, 2006) and SCRIP (Jones, 1999). Grid information is stored in a standardised structure as geo-hybrid grids. Based on this unified definition a standardised interface for the grid transformations is provided, thus simplifying the implemention of grid transformations in the model code. This article describes the main functionalities of the two MESSy infrastructure submodels GRID and IMPORT. The Supplement of this article

  5. Development of the Transportation Revenue Estimator and Needs Determination System (TRENDS) forecasting model : MPO sub-models and maintenance.

    Science.gov (United States)

    2011-11-01

    This report summarizes the technical work performed developing and incorporating Metropolitan Planning : Organization sub-models into the existing Texas Revenue Estimator and Needs Determination System : (TRENDS) model. Additionally, this report expl...

  6. 3-D turbulent particle dispersion submodel development. Quarterly progress report No. 2, 15 July--15 October 1991

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.J.

    1991-12-31

    The lack of a mathematical description of the interactions of fluid turbulence with other physics-chemical processes is a major obstacle in modeling many industrial program. Turbulent two-phase flow is a phenomenon that is of significant practical importance to coal combustion as well as other disciplines. The interactions of fluid turbulence with the particulate phase has yet to be accurately and efficiently modeled for these industrial applications. On 15 May 1991 work was initiated to cover four major tasks toward the development of a computational submodel for turbulent particle dispersion that would be applicable to coal combustion simulations. Those four tasks are: 1. A critical evaluation of the 2-D Lagrangian particle dispersion submodel, 2. Development of a 3-D submodel for turbulent particle dispersion, 3. Evaluation of the 3-D submodel for turbulent particle dispersion, 4. Exploration of extensions of the Lagrangian dispersion theory to other applications including chemistry-turbulence interactions.

  7. Mid-infrared diffuse reflectance spectroscopic examination of charred pine wood, bark, cellulose, and lignin: Implications for the quantitative determination of charcoal in soils

    Science.gov (United States)

    Reeves, J. B.; McCarty, G.W.; Rutherford, D.W.; Wershaw, R. L.

    2008-01-01

    Fires in terrestrial ecosystems produce large amounts of charcoal that persist in the environment and represent a substantial pool of sequestered carbon in soil. The objective of this research was to investigate the effect of charring on mid-infrared spectra of materials likely to be present in forest fires in order to determine the feasibility of determining charred organic matter in soils. Four materials (cellulose, lignin, pine bark, and pine wood) and char from these materials, created by charring for various durations (1 to 168 h) and at various temperatures (200 to 450 ??C), were studied. Mid-infrared spectra and measures of acidity (total acids, carboxylic acids, lactones, and phenols as determined by titration) were determined for 56 different samples (not all samples were charred at all temperatures/durations). Results showed spectral changes that varied with the material, temperature, and duration of charring. Despite the wide range of spectral changes seen with the differing materials and length/temperature of charring, partial least squares calibrations for total acids, carboxylic acids, lactones, and phenols were successfully created (coefficient of determination and root mean squared deviation of 0.970 and 0.380; 0.933 and 0.227; 0.976 and 0.120; and 0.982 and 0.101 meq/g, respectively), indicating that there is a sufficient commonality in the changes to develop calibrations without the need for unique calibrations for each specific material or condition of char formation. ?? 2008 Society for Applied Spectroscopy.

  8. Constitution of Drop-Tube-Generated Coal Chars from Vitrinite- and Inertinite-Rich South African Coals

    Energy Technology Data Exchange (ETDEWEB)

    Louw, Enette B.; Mitchell, Gareth D.; Wang, Juan; Winans, Randall E.; Mathews, Jonathan P.

    2016-01-21

    were characterized with SEM and optical microscopy, while quantitative information on the ordered nature of chars was obtained through XRD on de-ashed chars. The inertinite-rich coal experienced limited fluidity during heat-treatment, resulting in slower devolatilization, limited growth in crystallite height (11.8 to 12.6Å), only rounding of particle edges, and producing > 40% of mixed-dense type chars. The vitrinite-char showed more significant structural transformations; producing mostly (80%) extensively swollen crassisphere, tenuisphere, and network-type chars, and XRD showed a large increase in crystallite height (4.3 to 11.7Å). Nitrogen adsorption and small-angle X-ray scattering (SAXS) were utilized to compare the nitrogen surface areas and pore size distributions. Both chars were mostly mesoporous but the inertinite-rich char had double the average pore size, which also resulted in a larger nitrogen surface area since nitrogen can only access surface areas in larger pores. The BET surface area was 3.9 and 2.7 m2/g for the inertinite- and vitrinite-rich chars respectively. SAXS data showed that the vitrinite-rich char had 60% higher frequencies of pores in the micropore range. Helium porosimetry indicated that the inertinite-rich coal and resultant char had higher densities than the vitrinite coal and char; 1.6 and 2.0 g/cm3, compared to 1.3 and 1.9 g/cm3 (dry basis). Non-isothermal TGA burnout profiles showed the inertinite-rich char had a burnout temperature of 680°C, slightly higher than the vitrinite-rich char’s 650 °C. This, along with the peak shape and position in the burnout profiles indicate that the vitrinite-rich char has a higher reactivity. The higher reactivity is due to a combination of factors likely including less organization, grater porosity and access to the reactive site, less ash blocking, and char morphology differences.

  9. On Choosing Between Two Probabilistic Choice Sub-models in a Dynamic Multitask Environment

    Science.gov (United States)

    Soulsby, E. P.

    1984-01-01

    An independent random utility model based on Thurstone's Theory of Comparative Judgment and a constant utility model based on Luce's Choice Axiom are reviewed in detail. Predictions from the two models are shown to be equivalent under certain restrictions on the distribution of the underlying random process. Each model is applied as a stochastic choice submodel in a dynamic, multitask, environment. Resulting choice probabilities are nearly identical, indicating that, despite their conceptual differences, neither model may be preferred over the other based solely on its predictive capability.

  10. Kinetics and Mechanisms of NO(x) - Char Reduction.

    Energy Technology Data Exchange (ETDEWEB)

    Suurerg, E.M.; Lilly, W.D.; Aarna, I.

    1997-12-31

    Most industrially important carbons are produced from naturally occurring materials such as coal, oil, peat or wood by some form of thermal process. Chars are obtained from those natural materials as a residue after removal of the volatile matter. Chars (prepared from coal or other organic precursors) are non-graphitizable carbons, meaning that they cannot be transformed into graphitic carbon. Chars are comprised of elementary crystallites in parallel layers which are randomly oriented with respect to each other and are crosslinked together through weak bonds. Voids between crystallites determine the porosity of the char, and this plays an important role in char gasification behavior. Chars usually contain a pore size distribution, in which the larger macro- and mesopores play an important role in transport of reactants into the much smaller micropores, in which most gasification and combustion take place. Therefore, the effectiveness of micropores in gasification depends heavily on the numbers of meso- and macropores.

  11. Development, Verification and Validation of Enclosure Radiation Capabilities in the CHarring Ablator Response (CHAR) Code

    Science.gov (United States)

    Salazar, Giovanni; Droba, Justin C.; Oliver, Brandon; Amar, Adam J.

    2016-01-01

    With the recent development of multi-dimensional thermal protection system (TPS) material response codes including the capabilities to account for radiative heating is a requirement. This paper presents the recent efforts to implement such capabilities in the CHarring Ablator Response (CHAR) code developed at NASA's Johnson Space Center. This work also describes the different numerical methods implemented in the code to compute view factors for radiation problems involving multiple surfaces. Furthermore, verification and validation of the code's radiation capabilities are demonstrated by comparing solutions to analytical results, to other codes, and to radiant test data.

  12. Combustion characteristics of a solid propellant with a charring binder

    Science.gov (United States)

    Udlock, D. E.; Strand, L. D.

    1973-01-01

    A brief investigation of the combustion characteristics of a solid propellant containing a binder which chars, as opposed to melting or volatizing, has been made. The burning rate of the propellant with the charring binder was significantly higher than similar propellants containing non-charring binders. High speed motion pictures of the burning propellant showed that the aluminum burned on the regressing surface, rather than a short distance from it as is typical with composite propellants.

  13. Fiscal Sustainability and Social Cohesion. Common and Specific in EU Sub-models

    Directory of Open Access Journals (Sweden)

    Aura Gabriela SOCOL

    2010-03-01

    Full Text Available The European social model is characterized by a high heterogeneity degree, the member countries recording significant differences between the national redistribution systems. According to the existing gaps regarding the decreases of the poverty, the participation to the labour market and the protection against the labour market risks, we can identify five submodels within EU, the Northern one being the best adjusted to the structure of the European social model which has been modernized through the Lisbon strategy. Even though the finality of EU is represented by providing the social cohesion (the decrease of the poverty rate and of the income inequality, the progresses recorded during the period between 2000 and 2008 were quite low due to the evolutions of the Southern, Anglo-Saxon, Baltic and Romanian submodels. Within this study, we have explained why the increase of the state’s resources, of the welfare does not constitute a necessary and sufficient condition for the consolidation of the social cohesion within the European Union. On the contrary, the increase of the redistributed financial resources is able to generate sustainability problems in the budget deficit when the economic activity goes through an economic recession period.

  14. Development of Road Traffic Assignment and Assessment Sub-Model Applied in the Traffic Study ...

    Directory of Open Access Journals (Sweden)

    Dražen Topolnik

    2012-10-01

    Full Text Available The described sub-model is just one small segment of theTraffic Study of the City of Zagreb, in the development of whichnumerous foreign and national experts and institutions tookpart. After comprehensive collection and processing of inputdata, the traffic experts, using the software package "MVATRIPS" for the analysis and search for optimal solutions to theproblem of traffic system, provided the models of public urbantransit for the future.This paper describes the analysis and assessment of sub-models in road traffic assignment for the morning peak, afternoonpeak and average off-peak hours. The principles of assignmentprocedure have been described as well as the convergencetests. The following has been specified: the users categories,the public transit pre-load, and the passenger car unit(PC U. The key guideline in selecting the route is a generalisedformulation of costs presented in the paper. The procedures ofcalibration and the assessment of the finite model have alsobeen defined according to the screenline flows, link flows, andtravelling times. In the end, the summary is given of the basiccharacteristics of the finite travelling matrices.

  15. Production of activated carbon from TCR char

    Science.gov (United States)

    Stenzel, Fabian; Heberlein, Markus; Klinner, Tobias; Hornung, Andreas

    2016-04-01

    The utilization of char for adsorptive purposes is known since the 18th century. At that time the char was made of wood or bones and used for decoloration of fluids. In the 20th century the production of activated carbon in an industrial scale was started. The today's raw materials for activated carbon production are hard coal, peat, wood or coconut shells. All these materials entail costs especially the latter. Thus, the utilization of carbon rich residues (biomass) is an interesting economic opportunity because it is available for no costs or even can create income. The char is produced by thermo-catalytic reforming (TCR®). This process is a combination of an intermediate pyrolysis and subsequently a reforming step. During the pyrolysis step the material is decomposed in a vapor and a solid carbon enriched phase. In the second step the vapor and the solid phase get in an intensive contact and the quality of both materials is improved via the reforming process. Subsequently, the condensables are precipitated from the vapor phase and a permanent gas as well as oil is obtained. Both are suitable for heat and power production which is a clear advantage of the TCR® process. The obtained biochar from the TCR® process has special properties. This material has a very low hydrogen and oxygen content. Its stability is comparable to hard coal or anthracite. Therefore it consists almost only of carbon and ash. The latter depends from input material. Furthermore the surface structure and area can be influenced during the reforming step. Depending from temperature and residence time the number of micro pores and the surface area can be increased. Preliminary investigations with methylene blue solution have shown that a TCR® char made of digestate from anaerobic digestion has adsorptive properties. The decoloration of the solution was achieved. A further influencing factor of the adsorption performance is the particle size. Based on the results of the preliminary tests a

  16. Surface water submodel for the assessment of Canada`s nuclear fuel waste management concept. AECL research No. AECL-10290

    Energy Technology Data Exchange (ETDEWEB)

    Bird, G.A.; Stephenson, M.; Cornett, R.J.

    1992-12-31

    Probabilistic models (for geosphere, biosphere, and disposal vault) have been developed to predict nuclide transport in groundwater to the surface and biota resulting from release of nuclides from nuclear fuel wastes buried in vaults deep in plutonic rock. This report describes the surface water submodel of the biosphere model, which is a simple, generic mass balance model of a Canadian Shield lake. In the model, nuclide input to the lake from compacted sediments is the time-dependent mass output from the geosphere model. The surface water submodel then calculates nuclide concentrations in lake water and sediment; these values are used in other biosphere submodels to predict the radiological dose to biota. The paper discusses the selection of parameter values for the model and presents a sensitivity analysis of the model and results of model validation tests.

  17. Corrosive components of nutshells and their chars

    Directory of Open Access Journals (Sweden)

    Karczewski Mateusz

    2016-01-01

    Full Text Available Biomass combustion stands among various technologies pointed at fossil fuels consumption decrease. Biomass can be found in very diversified sources spread more evenly across the globe, can be burned with use of traditional combustion solutions and is more CO2 neutral in combustion than their fossil fuel counterparts. On the other hand biomass has several problems with composition that despite its potential diversity. Problem of excess moisture can be already solved by material selection or by preliminary pyrolysis. The main problem concerns however biomass ash composition. Biomass ashes are more prone to have higher quantities of potentially corrosive components than their coal counterparts. The example of such constituents are alkali metals, sulphur and chlorine. Ash basic composition is also important due to various ash properties like its melting temperature and slagging or fouling tendencies. To address the problem, several indices for fast properties prediction and earlier problem identification can be appointed. This work concentrates on ash quality evaluation for potentially attractive biomass fuel from nutshell materials and their corresponding char obtained by pyrolysis in 300, 450 and 550 °C. Pistachio and hazelnut shells with their chars will be analysed for corrosive compounds and their potential influence on combustion process.

  18. Gas cleaning with hot char beds studied by stable isotopes

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ahrenfeldt, Jesper; Ambus, Per

    2014-01-01

    The chemistry taking place in a high temperature char bed used for binding aromatic tar compounds has been studied in detail. 13C labelled tar compounds were used to trace the incorporation into the char bed using isotope ratio mass spectrometry (IRMS) and GC-MS. Furthermore, compounds labelled...

  19. Charring rate of wood exposed to a constant heat flux

    Science.gov (United States)

    R. H. White; H. C. Tran

    1996-01-01

    A critical factor in the fire endurance of a wood member is its rate of charring. Most available charring rate data have been obtained using the time-temperature curves of the standard fire resistance tests (ASTM E 119 and ISO 834) to define the fire exposure. The increased use of heat release calorimeters using exposures of constant heat flux levels has broadened the...

  20. Stable carbon isotope changes during artificial charring of propagules

    NARCIS (Netherlands)

    Poole, I.J.; Braadbaart, F.; Boon, J.J.; Bergen, P.F. van

    2002-01-01

    Charred organic remains are ubiquitous in the archaeological and fossil record and are often used to interpret past environments and climate. This study focuses on the physical and chemical alteration that takes place during heating (i.e. charring). Modifications to the internal and external

  1. NO Reduction over Biomass and Coal Char during Simultaneous Combustion

    DEFF Research Database (Denmark)

    Zhao, Ke; Glarborg, Peter; Jensen, Anker Degn

    2013-01-01

    This paper reports an experimental study of NO reduction over chars of straw, bark, bituminous coal, and lignite. The experiments were performed in a fixed bed reactor in the temperature range 850–1150 °C. The chars were generated by in situ pyrolysis at the reaction temperature to minimize further...

  2. CHARCOAL PACKED FURNACE FOR LOW-TECH CHARRING OF BONE

    DEFF Research Database (Denmark)

    Jacobsen, P.; Dahi, Elian

    1997-01-01

    A low-tech furnace for charring of raw bone using char coal is developed and tested. The furnace consists of a standard oil drum, fitted with simple materials as available in every market in small towns in developing counties. 80 kg of raw bone and 6 kg of charcoal are used for production of 50 k...

  3. Evaluation of solid fuel char briquettes from human waste.

    Science.gov (United States)

    Ward, Barbara J; Yacob, Tesfayohanes W; Montoya, Lupita D

    2014-08-19

    The developing world faces dual crises of escalating energy demand and lack of urban sanitation infrastructure that pose significant burdens on the environment. This article presents results of a study evaluating the feasibility of using human feces-derived char as a solid fuel for heating and cooking and a potential way to address both crises. The study determined the energy content and the elemental composition of chars pyrolyzed at 300, 450, and 750 °C. Fecal chars made at 300 °C were found to be similar in energy content to wood chars and bituminous coal, having a heating value of 25.6 ± 0.08 MJ/kg, while fecal chars made at 750 °C had an energy content of 13.8 ± 0.48 MJ/kg. The higher heating values of the studied chars were evaluated using their elemental composition and a published predictive model; results found good agreement between the measured and predicted values. Fecal chars made at low temperatures were briquetted with molasses/lime and starch binders. Briquettes made with 10% starch had an average impact resistance index of 79 and a higher heating value of 25 MJ/kg. These values are comparable to those of commercial charcoal briquettes, making fecal char briquettes a potential substitute that also contributes to the preservation of the environment.

  4. Anadromous char as an alternate food choice to marine animals: A synthesis of Hg concentrations, population features and other influencing factors

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Marlene S., E-mail: marlene.evans@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 11 Innovation Blvd., Saskatoon SK S7N 3H5 (Canada); Muir, Derek C.G. [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Rd., Burlington, ON L7R 4A6 (Canada); Keating, Jonathan [Environment Canada, Water Science and Technology Directorate, 11 Innovation Blvd., Saskatoon SK S7N 3H5 (Canada); Wang, Xiaowa [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Rd., Burlington, ON L7R 4A6 (Canada)

    2015-03-15

    and marine vertebrates in traditional diets. The known information on anadromous char is reviewed including population features, habitat, and harvests. Future Hg trend monitoring should focus on specific locations and harvest areas within these areas to better assess trends and influencing factors. - Highlights: • Mercury concentrations were very low (0.05 ± 0.02 µg/g) in anadromous char across northern Canada. • Hg concentrations increased with fish size, decreasing condition factor and cooler springs. • Hg concentrations seemed to increase on the long-term but decrease in recent times. • Char are a good food choice for those who want to maintain traditional diets while reducing Hg intake. • Anadromous char often are habitat-limited and most abundant in large lakes with ready sea access.

  5. CFD Wake Modelling with a BEM Wind Turbine Sub-Model

    Directory of Open Access Journals (Sweden)

    Anders Hallanger

    2013-01-01

    Full Text Available Modelling of wind farms using computational fluid dynamics (CFD resolving the flow field around each wind turbine's blades on a moving computational grid is still too costly and time consuming in terms of computational capacity and effort. One strategy is to use sub-models for the wind turbines, and sub-grid models for turbulence production and dissipation to model the turbulent viscosity accurately enough to handle interaction of wakes in wind farms. A wind turbine sub-model, based on the Blade Momentum Theory, see Hansen (2008, has been implemented in an in-house CFD code, see Hallanger et al. (2002. The tangential and normal reaction forces from the wind turbine blades are distributed on the control volumes (CVs at the wind turbine rotor location as sources in the conservation equations of momentum. The classical k-epsilon turbulence model of Launder and Spalding (1972 is implemented with sub-grid turbulence (SGT model, see Sha and Launder (1979 and Sand and Salvesen (1994. Steady state CFD simulations were compared with flow and turbulence measurements in the wake of a model scale wind turbine, see Krogstad and Eriksen (2011. The simulated results compared best with experiments when stalling (boundary layer separation on the wind turbine blades did not occur. The SGT model did improve turbulence level in the wake but seems to smear the wake flow structure. It should be noted that the simulations are carried out steady state not including flow oscillations caused by vortex shedding from tower and blades as they were in the experiments. Further improvement of the simulated velocity defect and turbulence level seems to rely on better parameter estimation to the SGT model, improvements to the SGT model, and possibly transient- instead of steady state simulations.

  6. The effects of the conditions of char formation on the physical properties of charred phenolic-nylon

    Science.gov (United States)

    Smyly, E. D.; Pears, C. D.

    1972-01-01

    A study was made of the effects of the conditions of char formation on the physical properties of charred phenolic nylon of 0.577 gm/cu cm density. It was found that the thermal conductivity and several of the monitors correlate well with degradation conditions. The monitors included electrical resistivity, sonic velocity, porosity, lattice spacing and crystallite size.

  7. Development and Verification of Enclosure Radiation Capabilities in the CHarring Ablator Response (CHAR) Code

    Science.gov (United States)

    Salazar, Giovanni; Droba, Justin C.; Oliver, Brandon; Amar, Adam J.

    2016-01-01

    With the recent development of multi-dimensional thermal protection system (TPS) material response codes, the capability to account for surface-to-surface radiation exchange in complex geometries is critical. This paper presents recent efforts to implement such capabilities in the CHarring Ablator Response (CHAR) code developed at NASA's Johnson Space Center. This work also describes the different numerical methods implemented in the code to compute geometric view factors for radiation problems involving multiple surfaces. Verification of the code's radiation capabilities and results of a code-to-code comparison are presented. Finally, a demonstration case of a two-dimensional ablating cavity with enclosure radiation accounting for a changing geometry is shown.

  8. Design of pyrolysis reactor for production of bio-oil and bio-char simultaneously

    Science.gov (United States)

    Aladin, Andi; Alwi, Ratna Surya; Syarif, Takdir

    2017-05-01

    The residues from the wood industry are the main contributors to biomass waste in Indonesia. The conventional pyrolysis process, which needs a large energy as well as to produce various toxic chemical to the environment. Therefore, a pyrolysis unit on the laboratory scale was designed that can be a good alternative to achieve zero-waste and low energy cost. In this paper attempts to discuss design and system of pyrolysis reactor to produce bio-oil and bio-char simultaneously.

  9. Variation of char structure during anthracite pyrolysis catalyzed by Fe{sub 2}O{sub 3} and its influence on char combustion reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Xuzhong Gong; Zhancheng Guo; Zhi Wang [Chinese Academy of Sciences, Beijing (China). State Key Laboratory of Multiphase Complex Systems

    2009-09-15

    Effects of Fe{sub 2}O{sub 3} on the pyrolysis reactivity of demineralized anthracite were investigated by a thermo-gravimetric analyzer, indicating that pyrolysis reactivity of Fe{sub 2}O{sub 3}-loaded demineralized anthracite was higher than that of raw demineralized anthracite when temperature is over 500{sup o}C. Chars were prepared from the two coal samples in muffle with heating progress, and their structures were analyzed using SEM, FTIR, XRD, and Raman. FTIR results showed that absorption peaks of functional groups on the surface of char from catalytic pyrolysis at 700{sup o}C were more than that of char from noncatalytic pyrolysis. Raman results demonstrated values of (I{sub D3} + I{sub D4})/IG of chars from catalytic pyrolysis and noncatalytic pyrolysis were 4.76 and 3.86, respectively, indicating that ordering of the char was decreased by Fe{sub 2}O{sub 3}. XRD analysis revealed that diffraction angle of the 002 peak did not shift; however, L{sub a} and L{sub c} decreased, indicating degree of graphitization for microcrystalline structure of char from catalytic pyrolysis was decreased. The results of FTIR, XRD, and Raman of the char showed that catalytic pyrolysis improved the formation of free radicals, while hindered polymerization and forming of basic structure units. Finally, combustion reactivity of the three chars, including char of raw demineralized anthracite (char-A), char of Fe{sub 2}O{sub 3}-loaded demineralized anthracite (char-B), and char of Fe{sub 2}O{sub 3}-loaded demineralized anthracite washed by HCl (char-C), was investigated using TG and indicated that their active order was char-B > char-C > char-A. The results corroborated that Fe{sub 2}O{sub 3} changed structure of anthracite char and improved combustion reactivity.

  10. Thermovolumetric investigations of steam gasification of coals and their chars

    Directory of Open Access Journals (Sweden)

    Porada Stanisław

    2017-01-01

    Full Text Available The process of steam gasification of three coals of various rank and three chars obtained from these coals by the ex-situ method at 900 °C was compared. In the coal gasification process, the pyrolysis stage plays a very important part, which is connected with its direct impact on the kinetics of gasification of the resulting char. What is more, taking into consideration the impact of pyrolysis conditions on char properties, it should be anticipated that the gasification kinetics of coal and char, formed from it by the ex situ method, will be different. In order to examine and compare the process of gasification of coals and chars, an isothermal thermovolumetric method, designed by the authors, was applied. For all the examined samples the measurements were performed at three temperatures, i.e. 850, 900, and 950 °C, and at the pressure of 0.1 MPa. An evaluation of the impact of raw material on the steam gasification of the examined samples was made. The carbon conversion degree and the kinetic parameters of CO and H2 formation reaction were calculated. It was observed that the course of gasification is different for coals and chars obtained from them and it can be concluded that coals are more reactive than chars. Values of kinetic parameters of carbon monoxide and hydrogen formation calculated for coals and corresponding chars are also different. Due to the observed differences the process of gasification of coals and of chars with steam should not be equated.

  11. CHAR CRYSTALLINE TRANSFORMATIONS DURING COAL COMBUSTION AND THEIR IMPLICATIONS FOR CARBON BURNOUT

    Energy Technology Data Exchange (ETDEWEB)

    ROBERT H. HURT

    1998-09-08

    Recent work at Sandia National Laboratories, Imperial College, and the U.K. utility PowerGen, has identified an important mechanism believed to have a large influence on unburned carbon levels from pulverized coal-fired boilers. That mechanism is char carbon crystalline rearrangements on subsecond times scales at temperatures of 1800 - 2500 K, which lead to char deactivation in the flame zones of furnaces. The so-called thermal annealing of carbons is a well known phenomenon, but its key role in carbon burnout has only recently been appreciated, and there is a lack of quantitative data in this time/temperature range. In addition, a new fundamental tool has recently become available to study crystalline transformations, namely high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars. Motivated by these new developments, this University Coal Research project has been initiated with the following two goals:  to determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history.  to characterize the effect of this thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis. Work is currently underway on the following three tasks: Task 1 Experimental technique development. The goal of this task is to develop and demonstrate an apparatus and procedure for measuring transient, high-temperature, thermal deactivation of coal chars. While peak gas temperatures in boilers are often in the range 1800 - 2000 K, peak particle temperatures can be much higher due to high rates of heat release at the particle surface due to exothermic carbon oxidation. The prototype transient heat treatment apparatus is based on an inert-gas purged graphite-rod sample holder that is subjected to rapid Joule heating to

  12. Structural and Compositional Transformations of Biomass Chars during Fast Pyrolysis

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Steibel, Markus; Spliethoff, Hartmut

    In this work the physical and chemical transformations of biomass chars during fast pyrolysis, considered as a 2nd stage of combustion, has been investigated. Seven biomasses containing different amount of ash and organic components were reacted at up to 1673 K with high heating rates in a wire......-mesh reactor and the resulting chars were retrieved. In order to obtain information on the structural and compositional transformations of the biomass chars, samples were subjected to elemental analysis, scanning electron microcopy with EDX and Raman spectrometry. The results show that there are significant...

  13. Adsorption of zinc ions on bone char using helical coil-packed bed columns and its mass transfer modeling

    DEFF Research Database (Denmark)

    Moreno-Pérez, J.; Bonilla-Petriciolet, A.; Rojas-Mayorga, C. K.

    2016-01-01

    char can be attributed to an ion-exchange mechanism. In summary, helical coil columns appear to be a feasible configuration for large-scale adsorption systems with high flow rates where a significant reduction on purification system size can be obtained without compromising the adsorbent performance....

  14. Study on coal char ignition by radiant heat flux.

    Science.gov (United States)

    Korotkikh, A. G.; Slyusarskiy, K. V.

    2017-11-01

    The study on coal char ignition by CO2-continuous laser was carried out. The coal char samples of T-grade bituminous coal and 2B-grade lignite were studied via CO2-laser ignition setup. Ignition delay times were determined at ambient condition in heat flux density range 90–200 W/cm2. The average ignition delay time value for lignite samples were 2 times lower while this difference is larger in high heat flux region and lower in low heat flux region. The kinetic constants for overall oxidation reaction were determined using analytic solution of simplified one-dimensional heat transfer equation with radiant heat transfer boundary condition. The activation energy for lignite char was found to be less than it is for bituminous coal char by approximately 20 %.

  15. Multidimensional simulation of diesel engine cold start with advanced physical submodels

    Energy Technology Data Exchange (ETDEWEB)

    Lippert, A.M. [GM R and D and Planning, Warren, MI (United States); Stanton, D.W. [Cummins Engine Co., Inc., Columbus, IN (United States); Rutland, C.J.; Reitz, R.D. [Wisconsin-Madison Univ., Engine Research Center, Madison, WI (United States); Hallett, W.L. [Ottawa Univ., Dept. of Mechanical Engineering, Ottawa, ON (Canada)

    2000-02-01

    The complex physical processes occurring during cold starting of diesel engines mandate the use of advanced physical submodels in computations. The present study utilises a continuous probability density function to represent more fully the range of compositions of commercial fuels. The model was applied to single-droplet calculations to validate the predictions against experimental results. Analysis of a high-pressure diesel spray showed axial composition gradients within the spray. Previous wall--film modelling was extended to include the continuous multicomponent fuel representation. Using these models, the cold-start behaviour of a heavy-duty diesel engine was analysed. The predictions show that multicomponent fuel modelling is critical to capturing realistic vaporisation trends. In addition, the spray--film interaction modelling is crucial to capturing the spray impingement and subsequent secondary atomisation. Heating the intake air temperature was shown to result in reduced ignition delay and accelerated vaporisation. Increasing the fuel temperature increased vaporisation prior to and away from the initial heat release. Increasing the injection pressure increased vaporisation without much change in the ignition delay. Split injections, with 75 per cent of the fuel contained in the second pulse, displayed a substantial reduction in ignition delay due to ignition of the first pulse. The timing of the first injection was found to be an important parameter due to differences in the spray impingement behaviour with different timings. (Author)

  16. High char imide-modified epoxy matrix resins

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1979-01-01

    Studies were performed to synthesize a novel class of bis (imide-amine) curing agents for epoxy matrix resins. Glass transition temperatures and char yield data of an epoxy cured with various bis (imide-amines) are presented. The room temperature and 350 F mechanical properties, and char yields of unidirectional graphite fiber laminates prepared with conventional epoxy and imide-modified epoxy resins are presented.

  17. STRUCTURE-BASED PREDICTIVE MODEL FOR COAL CHAR COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    CHRISTOPHER M. HADAD; JOSEPH M. CALO; ROBERT H. ESSENHIGH; ROBERT H. HURT

    1998-06-04

    During the past quarter of this project, significant progress continued was made on both major technical tasks. Progress was made at OSU on advancing the application of computational chemistry to oxidative attack on model polyaromatic hydrocarbons (PAHs) and graphitic structures. This work is directed at the application of quantitative ab initio molecular orbital theory to address the decomposition products and mechanisms of coal char reactivity. Previously, it was shown that the �hybrid� B3LYP method can be used to provide quantitative information concerning the stability of the corresponding radicals that arise by hydrogen atom abstraction from monocyclic aromatic rings. In the most recent quarter, these approaches have been extended to larger carbocyclic ring systems, such as coronene, in order to compare the properties of a large carbonaceous PAH to that of the smaller, monocyclic aromatic systems. It was concluded that, at least for bond dissociation energy considerations, the properties of the large PAHs can be modeled reasonably well by smaller systems. In addition to the preceding work, investigations were initiated on the interaction of selected radicals in the �radical pool� with the different types of aromatic structures. In particular, the different pathways for addition vs. abstraction to benzene and furan by H and OH radicals were examined. Thus far, the addition channel appears to be significantly favored over abstraction on both kinetic and thermochemical grounds. Experimental work at Brown University in support of the development of predictive structural models of coal char combustion was focused on elucidating the role of coal mineral matter impurities on reactivity. An �inverse� approach was used where a carbon material was doped with coal mineral matter. The carbon material was derived from a high carbon content fly ash (Fly Ash 23 from the Salem Basin Power Plant. The ash was obtained from Pittsburgh #8 coal (PSOC 1451). Doped

  18. Characterizing cytotoxic and estrogenic activity of Arctic char tissue extracts in primary Arctic char hepatocytes.

    Science.gov (United States)

    Petersen, Karina; Hultman, Maria T; Bytingsvik, Jenny; Harju, Mikael; Evenset, Anita; Tollefsen, Knut Erik

    2017-01-01

    Contaminants from various anthropogenic activities are detected in the Arctic due to long-range atmospheric transport, ocean currents, and living organisms such as migrating fish or seabirds. Although levels of persistent organic pollutants (POPs) in Arctic fish are generally low, local hot spots of contamination were found in freshwater systems such as Lake Ellasjøen at Bjørnøya (Bear Island, Norway). Higher concentrations of organic halogenated compounds (OHC), and higher levels of cytochrome P450 and DNA-double strand breaks were reported in Arctic char (Salvelinus alpinus) from this lake compared to fish from other lakes on Bjørnøya. Although several of the measured contaminants are potential endocrine disrupters, few studies have investigated potential endocrine disruptive effects of the contaminant cocktail in this fish population. The aim of this study was to compare acutely toxic and estrogenic potency of the cocktail of pollutants as evidenced by cytotoxic and/or estrogenic effects in vitro using extracts of Arctic char livers from contaminated Lake Ellasjøen with those from less contaminated Lake Laksvatn at Bjørnøya. This was performed by in situ sampling and contaminant extraction from liver tissue, followed by chemical analysis and in vitro testing of the following contaminated tissue extracts: F1-nonpolar OHC, F2-polar pesticides and metabolites of OHC, and F3-polar OHC. Contaminant levels were highest in extracts from Ellasjøen fish. The F2 and F3 extracts from Lake Laksvatn and Lake Ellasjøen fish reduced in vitro cell viability at a concentration ratio of 0.03-1 relative to tissue concentration in Arctic char. Only the F3 liver extract from Ellasjøen fish increased in vitro vitellogenin protein expression. Although compounds such as estrogenic OH-PCBs were quantified in Ellasjøen F3 extracts, it remains to be determined which compounds were inducing estrogenic effects.

  19. Effective Diffusion Coefficients in Coal Chars

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Jensen, Anker

    2001-01-01

    . Particle sizes in the range 0.05-5 mm were tested, and the effective diffusion coefficients were estimated from measured effectiveness factors using the Thiele modulus. At 1079 K the effective diffusion coefficients were 5.5 X 10(-6) m(2)/s and 6.8 X 10(-6) m(2)/s for N2O and NO, respectively....... The experimental results were compared with theoretical values calculated from the mean pore radius and the cross-linked pore model. The method of mean pore radius underestimated the effective diffusion coefficient more than an order of magnitude. Using the cross-linked pore model, the bimodal pore size....... In the case of strong pore diffusion limitations, the error in the interpretation of experimental results using the mean pore radius could be a factor of 5 on the intrinsic rate constant. For an average coal char reacting with oxygen at 1300 K, this would be the case for particle sizes larger than about 50...

  20. Synthesis and characterisation of laboratory-charred grass straw (Oryza sativa) and chestnut wood (Castanea sativa) as reference materials for black carbon quantification

    Energy Technology Data Exchange (ETDEWEB)

    Hammes, Karen; Schmidt [Zurich Univ., Dept. of Geography, Zurich (Switzerland); Smernik, Ronald J. [Adelaide Univ., School of Earth and Environmental Sciences, Adelaide, SA (Australia); Skjemstad, Jan O. [CSIRO Land and Water, Glen Osmond, SA (Australia); Herzog, Andreas; Vogt, Ulrich F. [EMPA Materials Science and Technology, Lab. for High Performance Ceramics, Duebendorf (Switzerland)

    2006-11-15

    We synthesised large ( about 2 kg) quantities of two chars for use as commercially available reference materials for the quantification of black carbon (BC). We pyrolysed chestnut wood (Castanea sativa) and grass straw (Oryza sativa) at 450 deg C under a N{sub 2} atmosphere, which mimics the oxygen-free conditions on the inside of burning material at a moderate burning temperature. The charred materials were dominated by aromatic carbon (about 70%), had low H/C (about 0.7) and O/C (about 0.3) ratios and low surface areas (2-6 m{sup 2} g{sup -1} ). Isotopic changes on charring were small (<0.3 0/00). In these respects, the synthesised chars were similar to chars produced at low temperature (<500 deg C) in natural fires and thus may prove to be appropriate materials for calibrating BC quantification methods. Both chars have been used in a comparative study of BC quantification. (Author)

  1. Sub-modeling approach for obtaining structural stress histories during dynamic analysis

    Directory of Open Access Journals (Sweden)

    T. T. Rantalainen

    2013-02-01

    Full Text Available Modern machine structures are often fabricated by welding. From a fatigue point of view, the structural details and especially, the welded details are the most prone to fatigue damage and failure. Design against fatigue requires information on the fatigue resistance of a structure's critical details and the stress loads that act on each detail. Even though, dynamic simulation of flexible bodies is already current method for analyzing structures, obtaining the stress history of a structural detail during dynamic simulation is a challenging task; especially when the detail has a complex geometry. In particular, analyzing the stress history of every structural detail within a single finite element model can be overwhelming since the amount of nodal degrees of freedom needed in the model may require an impractical amount of computational effort. The purpose of computer simulation is to reduce amount of prototypes and speed up the product development process. Also, to take operator influence into account, real time models, i.e. simplified and computationally efficient models are required. This in turn, requires stress computation to be efficient if it will be performed during dynamic simulation. The research looks back at the theoretical background of multibody simulation and finite element method to find suitable parts to form a new approach for efficient stress calculation. This study proposes that, the problem of stress calculation during dynamic simulation can be greatly simplified by using a combination of Floating Frame of Reference Formulation with modal superposition and a sub-modeling approach. In practice, the proposed approach can be used to efficiently generate the relevant fatigue assessment stress history for a structural detail during or after dynamic simulation. Proposed approach is demonstrated in practice using one numerical example. Even though, examples are simplified the results show that approach is applicable and can be used as

  2. Slow pyrolysis of poultry litter and pine woody biomass: impact of chars and bio-oils on microbial growth.

    Science.gov (United States)

    Das, K C; Garcia-Perez, M; Bibens, B; Melear, N

    2008-06-01

    Accidental or prescribed fires in forests and in cultivated fields, as well as primitive charcoal production practices, are responsible for the release of large amounts of gases, char and condensable organic molecules into the environment. This paper describes the impact of condensable organic molecules and chars resulting from the slow pyrolysis of poultry litter, pine chips and pine pellets on the growth of microbial populations in soil and water. The proximate and elemental analyses as well as the content of proteins, cellulose, hemicellulose, lignin, and ash for each of these bio-materials are reported. The yields and some properties of char and condensable liquids are also documented. The behavior of microbial populations in soil and water is followed through respiration studies. It was found that biological activity was highest when aqueous fractions from poultry litter were applied in water. Cumulative oxygen consumption over a 120-h period was highest in the aqueous phases from poultry litter coarse fraction (1.82 mg/g). On average the oxygen consumption when oily fractions from poultry litter were applied represented 44 to 62% of that when aqueous fractions were applied. Pine chip and pine pellet derived liquids and chars produced respiration activity that were an order of magnitude lower than that of poultry litter liquid fractions. These results suggest that the growth observed is due to the effect of protein-derived molecules.

  3. Char Crystalline Transformations During Coal Combustion and Their Implication for Carbon Burnout

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, Robert H

    1997-12-30

    Recent work at Sandia National Laboratories, Imperial College, and the U.K. utility PowerGen, has identified an important mechanism believed to have a large influence on unburned carbon levels from pulverized coal fired boilers. That mechanism is char carbon crystalline rearrangements on subsecond times scales at temperatures of 1800 - 2500 K, which lead to char deactivation in the flame zones of furnaces. The so-called thermal annealing of carbons is a well known phenomenon, but its key role in carbon burnout has only recently been appreciated, and there is a lack of quantitative data in this time/temperature range. In addition, a new fundamental tool has recently become available to study crystalline transformations, namely high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars. Motivated by these new developments, this University Coal Research project has been initiated with the following two goals: to determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history. to characterize the effect of this thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis. Work is currently underway on the following three tasks: Task 1 Experimental technique development. The goal of this task is to develop and demonstrate an apparatus and procedure for measuring transient, high-temperature, thermal deactivation of coal chars. While peak gas temperatures in boilers are often in the range 1800 - 2000 K, peak particle temperatures can be much higher due to high rates of heat release at the particle surface due to exothermic carbon oxidation. The prototype transient heat treatment apparatus is based on an inert-gas purged graphite-rod sample holder that is subjected to rapid Joule heating to

  4. Disintegration of beech wood char during thermal conversion

    DEFF Research Database (Denmark)

    Hindsgaul, Claus

    In the present work the processes occurring in the structures of slowly pyrolysed beech wood char during thermal gasification have been investigated. Emphasis was put on physical changes and gas transport properties during conversion. The highly anisotropic structure of wood was preserved in its...... differences of 3—4 orders of magnitude between the longitudinal and other directions in freshly pyrolysed beech wood char. Diffusion in the longitudinal direction of the beech wood char before gasification corresponded to direct, unobstructed diffusion through its vessel cells. Radial and tangential diffusion...... were limited by Knudsen diffusion through the pits in the wood cell walls for degrees of conversion by gasification up to at least 0.5. A computer model of slab gasification based on the diffusion measurements successfully predicted the mass loss rate during diffusion-limited gasification of beech wood...

  5. Charring Rate for Fire Exposed X-Lam

    Science.gov (United States)

    Wong, Bernice VY; Fah Tee, Kong

    2017-06-01

    Design of timber structures has been outlined in Eurocode 5. Notional charring rate for softwood and hardwood timber is given. For the performance of X-LAM panels in fire, only little information on charring is available and whether the fire behaviour of X-LAM is similar to homogenous timber panels has not yet been systematically analysed. This paper presents an overview of fire performance of X-LAM and evaluation of its resistance to elevated temperature as an element of structure in comparison to homogeneous timber panels. Numerical study has been carried out based on available experimental results. Charring rates for X-LAM panels obtained from experimental results are compared with those obtained from Eurocode 5 and proposed simplified model.

  6. Studying the specific features pertinent to combustion of chars obtained from coals having different degrees of metamorphism and biomass chars

    Science.gov (United States)

    Bestsennyi, I. V.; Shchudlo, T. S.; Dunaevskaya, N. I.; Topal, A. I.

    2013-12-01

    Better conditions for igniting low-reaction coal (anthracite) can be obtained, higher fuel burnout ratio can be achieved, and the problem of shortage of a certain grade of coal can be solved by firing coal mixtures and by combusting coal jointly with solid biomass in coal-fired boilers. Results from studying the synergetic effect that had been revealed previously during the combustion of coal mixtures in flames are presented. A similar effect was also obtained during joint combustion of coal and wood in a flame. The kinetics pertinent to combustion of char mixtures obtained from coals characterized by different degrees of metamorphism and the kinetics pertinent to combustion of wood chars were studied on the RSK-1D laboratory setup. It was found from the experiments that the combustion rate of char mixtures obtained from coals having close degrees of metamorphism is equal to the value determined as a weighted mean rate with respect to the content of carbon. The combustion rate of char mixtures obtained from coals having essentially different degrees of metamorphism is close to the combustion rate of more reactive coal initially in the process and to the combustion rate of less reactive coal at the end of the process. A dependence of the specific burnout rate of carbon contained in the char of two wood fractions on reciprocal temperature in the range 663—833 K is obtained. The combustion mode of an experimental sample is determined together with the reaction rate constant and activation energy.

  7. Strategy for Passivating Char Efficiently at the Pilot Scale

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, Timothy C [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-18

    Fast pyrolysis is a promising pathway for the commercialization of liquid transportation fuels from biomass. Fast pyrolysis is performed at moderate heat (450-600 degrees Celcius) in an oxygen-deficient environment. One of the products of fast pyrolysis is biochar, which is often used as a heat source or as a soil amendment. Biochar is a partially reacted solid that is created in the production of bio-oil during fast pyrolysis. Biochar produced at these conditions contains significant quantities of carbon that adsorb oxygen when exposed to air. Biochar adsorption of oxygen is an exothermic process that may generate sufficient heat for combustion in ambient air. Biochar is also a self-insulating material which compounds the effects of heat generated internally. These factors lead to safety concerns and material handling difficulties. The Thermochemical Process Development Unit at the National Renewable Energy Laboratory operates a pilot plant that may be configured for fast pyrolysis, gasification, and will be introducing catalytic fast pyrolysis capabilities in 2018. The TCPDU designed and installed a system to introduce oxygen to collected biochar systematically for a controlled passivation. Biochar is collected and cooled in an oxygen deficient environment during fast pyrolysis. Oxygen is then introduced to the biochar on a mass flow basis. A sparger imbedded within the biochar sample near the bottom of the bed flows air diluted with nitrogen into the char bed, and excess gasses are removed from the top of the collection drum, above the char bed. Pressure within the collection drum is measured indicating adequate flow through filters. Sample weight is recorded before and after passivation. During passivation, temperature is measured at 18 points within the char bed. Oxygen content and temperature are measured leaving the char bed. Maximum temperature parameters were established to ensure operator safety during biochar passivation. Extensive passivation data was

  8. Heat Transfer in a Fixed Bed of Straw Char

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Jensen, Anker

    2003-01-01

    A model for the thermal conductivity of a straw char bed has been developed. The model extends the work of Yagi and Kunii to describe heat transfer in a bed of cylinders, using a relationship between the interparticle distance and the external porosity. To verify the model, thermal conductivity...... the experimental uncertainty over the range of conditions investigated. The heat transfer model was used in a parametric study to evaluate the effect of gas flow rate, particle diameter, porosity, and temperature on the thermal conductivity in a straw char bed....

  9. Suspension Combustion of Wood: Influence of Pyrolysis Conditions on Char Yield, Morphology, and Reactivity

    DEFF Research Database (Denmark)

    Dall'Ora, Michelangelo; Jensen, Peter Arendt; Jensen, Anker Degn

    2008-01-01

    Chars from pine and beech wood were produced by fast pyrolysis in an entrained flow reactor and by slow pyrolysis in a thermogravimetric analyzer. The influence of pyrolysis temperature, heating rate and particle size on char yield and morphology was investigated. The applied pyrolysis temperature......, whereas beech sawdust chars showed a somewhat less drastic change of morphology with respect to the parent fuel. Char produced by low heating rate pyrolysis fully retained the original fibrous structure of wood. Fast pyrolysis chars were significantly more reactive than slow pyrolysis chars; moreover...... free basis, whereas it was about 15−17% for slow pyrolysis (10−20 K/min); char yield decreased as pyrolysis temperature increased. During fast pyrolysis wood particles underwent melting, yet to different extents for the two investigated fuels: pine wood produced chars of porous spherical particles...

  10. Formation, Structure and Properties of Amorphous Carbon Char from Polymer Materials in Extreme Atmospheric Reentry Environments

    Science.gov (United States)

    Lawson, John W.

    2010-01-01

    Amorphous carbonaceous char produced from the pyrolysis of polymer solids has many desirable properties for ablative heat shields for space vehicles. Molecular dynamics simulations are presented to study the transformation of the local atomic structure from virgin polymer to a dense, disordered char [1]. Release of polymer hydrogen is found to be critical to allow the system to collapse into a highly coordinated char structure. Mechanisms of the char formation process and the morphology of the resulting structures are elucidated. Thermal conductivity and mechanical response of the resulting char are evaluated [2]. During reenty, the optical response and oxidative reactivity of char are also important properties. Results of ab initio computations of char optical functions [3] and char reactivity [4] are also presented.

  11. A volumetric ablation model of EPDM considering complex physicochemical process in porous structure of char layer

    OpenAIRE

    Yang Liu; Xiao-Jing Yu; Jian-Ming Ma; Yi-Wen Guan; Jiang Li; Qiang Li; Sa Yang

    2017-01-01

    A volumetric ablation model for EPDM (ethylene- propylene-diene monomer) is established in this paper. This model considers the complex physicochemical process in the porous structure of a char layer. An ablation physics model based on a porous structure of a char layer and another model of heterogeneous volumetric ablation char layer physics are then built. In the model, porosity is used to describe the porous structure of a char layer. Gas diffusion and chemical reactions are introduced to ...

  12. STRUCTURE-BASED PREDICTIVE MODEL FOR COAL CHAR COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    Robert H. Hurt; Eric M. Suuberg

    2000-05-03

    This report is part on the ongoing effort at Brown University and Ohio State University to develop structure based models of coal combustion. A very fundamental approach is taken to the description of coal chars and their reaction processes, and the results are therefore expected to have broad applicability to the spectrum of carbon materials of interest in energy technologies. This quarter, our work on structure development in carbons continued. A combination of hot stage in situ and ex situ polarized light microscopy was used to identify the preferred orientational of graphene layers at gas interfaces in pitches used as carbon material precursors. The experiments show that edge-on orientation is the equilibrium state of the gas/pitch interface, implying that basal-rich surfaces have higher free energies than edge-rich surfaces in pitch. This result is in agreement with previous molecular modeling studies and TEM observations in the early stages of carbonization. The results may have important implications for the design of tailored carbons with edge-rich or basal-rich surfaces. In the computational chemistry task, we have continued our investigations into the reactivity of large aromatic rings. The role of H-atom abstraction as well as radical addition to monocyclic aromatic rings has been examined, and a manuscript is currently being revised after peer review. We have also shown that OH radical is more effective than H atom in the radical addition process with monocyclic rings. We have extended this analysis to H-atom and OH-radical addition to phenanthrene. Work on combustion kinetics focused on the theoretical analysis of the data previously gathered using thermogravametric analysis.

  13. Low-energy and chemical-free activation of pyrolytic tire char and its adsorption characteristics.

    Science.gov (United States)

    Quek, Augustine; Balasubramanian, Rajasekhar

    2009-06-01

    It is generally known that the solid char obtained from pyrolysis of scrap rubber tires can be used as an adsorbent for several applications such as wastewater treatment. In this study, scrap tires were first pyrolyzed under nitrogen (N2) or carbon dioxide (CO2) gas under various temperatures to produce char. The char was activated in situ by post-pyrolysis oxygenation (PPO) at different temperature ranges as soon as the pyrolysis process was completed. Elemental and spectroscopic analyses showed significant zinc content in the char after PPO. Batch-mode removal of aqueous copper (Cu) using the chars revealed that, for N2 and CO2, the optimum condition for pyrolysis was at 550 degrees C and for activation was from 550 to 250 degrees C. Although CO2-pyrolyzed char had lower Cu and lead (Pb) removal than N2-pyrolyzed char, it had higher char yields. For both N2- and CO2-pyrolyzed char, activation with PPO improved their heavy metal removal efficiencies significantly compared with unactivated char. PPO chars had much faster removal rates and higher Cu removal compared with both pyrolyzed, unactivated char and commercial activated carbons.

  14. The thermal history of char as disclosed by carbon isotope ratios

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ambus, Per; Ahrenfeldt, Jesper

    In laboratory experiments, biomass char was produced under controlled conditions using wood chips from French pinewood. Different char qualities were obtained by pyrolysing the biomass at similar heating rates with end-temperatures ranging from 250 to 1000 o C. The char was analysed by flash...

  15. Experimental comparison of biomass chars with other catalysts for tar reduction

    NARCIS (Netherlands)

    Abu El-Rub, Ziad; Bramer, Eduard A.; Brem, Gerrit

    2008-01-01

    In this paper the potential of using biomass char as a catalyst for tar reduction is discussed. Biomass char is compared with other known catalysts used for tar conversion. Model tar compounds, phenol and naphthalene, were used to test char and other catalysts. Tests were carried out in a fixed bed

  16. Adsorption of Escherichia coli Using Bone Char 1*ABBAS REZAEE ...

    African Journals Online (AJOL)

    Michael Horsfall

    density and iodine number. Nebulizer system applied to convert the E.coli ... the information obtained in the paper is of fundamental significance for the mineral adsorbents especially bone char in cleaning of indoor bioaerosol. ..... laboratory exercise was devoted with the goal of: -. Obtaining high efficiency for removal of ...

  17. Evaporation of biomass fast pyrolysis oil: evaluation of char formation

    NARCIS (Netherlands)

    Balegedde Ramachandran, P.; van Rossum, G.; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.

    2009-01-01

    Evaporation experiments of biomass fast pyrolysis oil and its aqueous fractions at low (TGA-10°C/min, Glass tube-100°C/min) and high (atomization ~10 6°C/min) heating rates are performed. Slow heating of pyrolysis oil produced ~28% char (on carbon basis), whereas atomization of oil droplets (~117µm)

  18. The mechanism of char ignition in fluidized bed combustors

    NARCIS (Netherlands)

    Siemons, R.V.

    1987-01-01

    Knowledge about ignition processes of coal in fluidized beds is of importance for the start-up and dynamic control of these combustors. Initial experiments in a transparent fluidized bed scale model showed the existence of a considerable induction period for the ignition of char, especially at low

  19. Adsorption of Escherichia coli Using Bone Char | Rezaee | Journal ...

    African Journals Online (AJOL)

    The aim of study was providing a novel adsorbent for the removal of Escherichia coli (E.coli) as a microbial model from contaminated air especially in hospital units using bone char (BC). The BC was prepared from cattle animal bone by pyrolysis in a furnace at 450°C for 2 h. The characteristics of BC have been determined ...

  20. Characterisation of coal and chars in fluidised bed gasification

    CSIR Research Space (South Africa)

    Oboirien, BO

    2009-03-01

    Full Text Available temperature range of 900 to 935oC. Char residual remaining after atmospheric gasification in a pilot plant bubbling fluidised bed reactor were analysed by petrographic techniques, X-ray diffraction, scanning electron microscopy (SEM), EDX, Raman spectroscopy...

  1. Production and characterization of chars from cherry pulp via pyrolysis.

    Science.gov (United States)

    Pehlivan, E; Özbay, N; Yargıç, A S; Şahin, R Z

    2017-12-01

    Pyrolysis is an eco-friendly process to achieve valuable products like bio-oil, char and gases. In the last decades, biochar production from pyrolysis of a wide variety of industrial and agricultural wastes become popular, which can be utilized as adsorbent instead of the expensive activated carbons. In this study, cherry pulp was pyrolyzed in a fixed bed tubular reactor at five different temperatures (400, 500,550, 600 and 700 °C) and three different heating rates (10, 100 and 200 °C/min) to obtain biochar. Proximate, ultimate, nitrogen adsorption/desorption isotherms, scanning electron microscopy, thermogravimetric analysis, x-ray fluorescence, x-ray diffraction, and Fourier transform infrared spectroscopy were performed on cherry pulp and its chars to examine the chemical alterations after the pyrolysis process. Biochar yields were decreased with increasing pyrolysis temperature and heating rate, based on experimental results. Porous biochars are carbon rich and includes high potassium content. The aromaticity of biochars increased and O/C mass ratio reduced with an increase in the pyrolysis temperature as a result of the development of compact aromatic structure in char. Pyrolysis provides a promising conversion procedure for the production of high energy density char which has promising applications in existing coal-fired boilers without any upgrading. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Synthesis of carbon-encapsulated metal nanoparticles from wood char

    Science.gov (United States)

    Yicheng Du; Chuji Wang; Hossein Toghiani; Zhiyong Cai; Xiaojian Liu; Jilei Zhang; Qiangu Yan

    2010-01-01

    Carbon-encapsulated metal nanoparticles were synthesized by thermal treatment of wood char, with or without transition metal ions pre-impregnated, at 900ºC to 1,100ºC. Nanoparticles with concentric multilayer shells were observed. The nanoparticles were analyzed by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction...

  3. Heat Transfer in a Fixed Biomass Char Bed

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Glarborg, P.

    2002-01-01

    A thermal conductivity model based on the Yagi and Kunii model together with a bed model was developed to describe the thermal conductivity of a straw char bed. The bed model describes the relationship between the distance between particles and the external porosity. To verify the model, thermal ...

  4. Arsenate adsorption onto iron oxide amended rice husk char.

    Science.gov (United States)

    Cope, Christopher O; Webster, Damon S; Sabatini, David A

    2014-08-01

    In this study, rice husks were charred at 550 °C in a partially sealed ceramic vessel for 30minutes to create a high specific surface area (SSA) rice husk char (RHC). The RHC was then amended with iron oxides using dissolved ferric nitrate, Fe(NO3)3⋅9H2O, to provide a surface chemistry conducive to arsenic adsorption. The 550 °C iron oxide amended rice husk char's (550 IOA-RHC's) SSA was nearly 2.5 orders of magnitude higher and the arsenate adsorptive level was nearly 2 orders of magnitude higher than those reported for iron oxide amended sand, thus indicating a positive relationship between post-amendment SSA and arsenate adsorptive levels. Rice husks were then charred at temperatures ranging from 450 °C to 1050 °C to create an even higher SSA material, which might further increase arsenate adsorptive levels. The 950 °C RHC was chosen for amendment due to its high SSA and feasibility of being produced in the field. Once amended, the 950 °C iron oxide amended rice husk char (950 IOA-RHC) improved the arsenate adsorption capacity by thus confirming a positive relationship, though not a linear relationship, between post-amendment SSA and arsenic adsorptive capacity. Further study demonstrated that post-amendment mesoporous volume and mesoporous surface area appear to be better indicators of arsenic adsorptive capacity than SSA or iron content. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Atmosphere submodel for the assessment of Canada's nuclear fuel waste management concept. AECL research No. AECL-9889

    Energy Technology Data Exchange (ETDEWEB)

    Amiro, B.D.

    1992-01-01

    The Nuclear Fuel Waste Management Program has as one of its objectives to assess the movement of nuclides using modelling techniques to calculate the radiological dose to humans and concentrations of contaminants in the environment. To achieve these goals, a biosphere model, comprising four submodels, was developed. This report describes the atmosphere submodel and the pathways through which nuclides may move through the atmosphere. The model describes the processes of nuclide suspension, dispersion, and deposition. Surface water and soil are considered as primary sources of nuclide fluxes to the atmosphere. The model considers natural phenomena such as wind erosion of soil, forest fires, gaseous emissions from soil, and bubble bursting at lake surfaces. Anthropogenic processes, such as wood burning for energy, are also modelled, and nuclide concentrations in both outdoor and indoor air are calculated. The model combines a variety of techniques, including mass loading concepts, flux density estimates, numerical dispersion models, and specific-activity relationships. The model is probabilistic, with transport modelled using simple mass transfer equations and variability incorporated by distributing values for parameters. This report documents the model equations, the parameter values, and comparisons of pathways.

  6. A case study of an enhanced eutrophication model with stoichiometric zooplankton growth sub-model calibrated by Bayesian method.

    Science.gov (United States)

    Yang, Likun; Peng, Sen; Sun, Jingmei; Zhao, Xinhua; Li, Xia

    2016-05-01

    Urban lakes in China have suffered from severe eutrophication over the past several years, particularly those with relatively small areas and closed watersheds. Many efforts have been made to improve the understanding of eutrophication physiology with advanced mathematical models. However, several eutrophication models ignore zooplankton behavior and treat zooplankton as particles, which lead to the systematic errors. In this study, an eutrophication model was enhanced with a stoichiometric zooplankton growth sub-model that simulated the zooplankton predation process and the interplay among nitrogen, phosphorus, and oxygen cycles. A case study in which the Bayesian method was used to calibrate the enhanced eutrophication model parameters and to calculate the model simulation results was carried out in an urban lake in Tianjin, China. Finally, a water quality assessment was also conducted for eutrophication management. Our result suggests that (1) integration of the Bayesian method and the enhanced eutrophication model with a zooplankton feeding behavior sub-model can effectively depict the change in water quality and (2) the nutrients resulting from rainwater runoff laid the foundation for phytoplankton bloom.

  7. Assessment of chars from black coal carbonization for adsorption treatment of waste water from coking plants

    Energy Technology Data Exchange (ETDEWEB)

    Wolany, B.; Szkuta-Pochopien, T.; Malczyk, R.; Sekula, M.

    1985-06-01

    The Institute for Chemical Coal Processing investigated efficiency of carbon adsorption in treatment of waste water from a coking plant in Poland. Four types of adsorption media were used: a coarse-grained non-activated char, a fine-grained non-activated char, a coarse-grained activated char and Carbopol Z-4 activated carbon produced on a commercial scale. The chars were produced by carbonization of black coal from Poland in a rotary chamber using semicoke as heat carrier. Sorptive properties of 4 types of chars were compared. All the tested chars were characterized by sorptive properties in relation to chemical compounds from waste water. The coarse-grained activated char was superior to other chars. The working sorptive capacity of the coarse-grained activated char amounted to 86% of the capacity of Carbopol Z-4 activated carbon (when 2 chars were used for reducing chemical oxygen demand of waste water to about 35% of the initial level, treatment efficiency amounted to 65%). Use of the coarse-grained activated char for waste water treatment in coking plants on a commercial scale is recommended. 13 references.

  8. Effect of temperature and pressure on characteristics and reactivity of biomass-derived chars.

    Science.gov (United States)

    Recari, J; Berrueco, C; Abelló, S; Montané, D; Farriol, X

    2014-10-01

    This study evaluates the influence of pyrolysis temperature (350-450°C) and pressure (0.1-2.0MPa) on product yields and char properties. Spruce chars were produced under slow pyrolysis conditions in a fixed bed reactor. Special attention was devoted to the study of the oxidation reactivity of the produced chars, and its relationship with the evaluated char properties. The obtained results showed that the effect of the pyrolysis condition on char production and in particular on the mechanism of secondary char formation strongly influenced the char reactivity. Additionally it has been observed that the interval of temperature between 350 and 450°C may be key in the mechanism of tar repolymerization. The information provided in this study is of great interest for the determination of optimal operation conditions and the design of new gasification concepts or the development of bioenergy carriers via pyrolysis technologies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Structure Based Predictive Model for Coal Char Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Robert Essenhigh; Christopher Hadad

    2000-12-30

    This unique collaborative project has taken a very fundamental look at the origin of structure, and combustion reactivity of coal chars. It was a combined experimental and theoretical effort involving three universities and collaborators from universities outside the U.S. and from U.S. National Laboratories and contract research companies. The project goal was to improve our understanding of char structure and behavior by examining the fundamental chemistry of its polyaromatic building blocks. The project team investigated the elementary oxidative attack on polyaromatic systems, and coupled with a study of the assembly processes that convert these polyaromatic clusters to mature carbon materials (or chars). We believe that the work done in this project has defined a powerful new science-based approach to the understanding of char behavior. The work on aromatic oxidation pathways made extensive use of computational chemistry, and was led by Professor Christopher Hadad in the Department of Chemistry at Ohio State University. Laboratory experiments on char structure, properties, and combustion reactivity were carried out at both OSU and Brown, led by Principle Investigators Joseph Calo, Robert Essenhigh, and Robert Hurt. Modeling activities were divided into two parts: first unique models of crystal structure development were formulated by the team at Brown (PI'S Hurt and Calo) with input from Boston University and significant collaboration with Dr. Alan Kerstein at Sandia and with Dr. Zhong-Ying chen at SAIC. Secondly, new combustion models were developed and tested, led by Professor Essenhigh at OSU, Dieter Foertsch (a collaborator at the University of Stuttgart), and Professor Hurt at Brown. One product of this work is the CBK8 model of carbon burnout, which has already found practical use in CFD codes and in other numerical models of pulverized fuel combustion processes, such as EPRI's NOxLOI Predictor. The remainder of the report consists of detailed

  10. The influence of inorganic materials on the thermal deactivation of fuel chars

    Energy Technology Data Exchange (ETDEWEB)

    Zolin, A.; Jensen, A.; Jensen, P.A.; Frandsen, F.; Dam-Johansen, K. [Technical University of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

    2001-10-01

    The influence of inorganic material on the thermal deactivation of a biomass fuel and a coal was investigated. Reactivity experiments were performed for chars from wheat and leached wheat straw pyrolysed at a wide range of heat treatment temperatures (HTT) in a thermogravimetric analyzer (TGA) and entrained flow reactor (EFR). The HTT were varied from 973 to 1673 K in from the low rank coal, Dietz and demineralized Dietz, prepared in the TGA at the same conditions as the biomass chars. From the TGA data, the biomass chars show at an HTT a higher reactivity than the coal chars, but owing to thermal deactivation the reactivity of all fuel chars converge at the highest HTT. The influence of catalysts for char oxidation in both the biomass and the coal is significant up to HTT = 1273 K. Likely mechanisms for the loss of catalytic activity at high HTT in the TGA are discussed. The straw chars prepared in the EFR are on average a factor 30 to 40 times more reactive than the leached straw chars prepared at the same conditions in this reactor. SEM analysis of the EFR chars reveal that the in active catalyst, potassium is found both in the organic matrix and in Si-rich regions of the char. Straw and leached straw produce chars that may have undergone a plastic stage during pyrolysis, similar to what is observed in coal chars. Using a common activation energy, the reactivity of the leached straw char prepared in the EFR at 1613 K is slightly higher than that of a typical char from a coal used in utility boilers (Cerrejon), suggesting that leached straw can be used in co-firing applications. 48 refs., 10 figs., 2 tabs.

  11. STRUCTURE-BASED PREDICTIVE MODEL FOR COAL CHAR COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    CHRISTOPHER M. HADAD; JOSEPH M. CALO; ROBERT H. ESSENHIGH; ROBERT H. HURT

    1999-01-13

    Significant progress continued to be made during the past reporting quarter on both major technical tasks. During the reporting period at OSU, computational investigations were conducted of addition vs. abstraction reactions of H, O(3 P), and OH with monocyclic aromatic hydrocarbons. The potential energy surface for more than 80 unique reactions of H, O ( 3 P), and OH with aromatic hydrocarbons were determined at the B3LYP/6-31G(d) level of theory. The calculated transition state barriers and reaction free energies indicate that the addition channel is preferred at 298K, but that the abstraction channel becomes dominant at high temperatures. The thermodynamic preference for reactivity with aromatic hydrocarbons increases in the order O(3 P) < H < OH. Abstraction from six-membered aromatic rings is more facile than abstraction from five-membered aromatic rings. However, addition to five-membered rings is thermodynamically more favorable than addition to six-membered rings. The free energies for the abstraction and addition reactions of H, O, and OH with aromatic hydrocarbons and the characteristics of the respective transition states can be used to calculate the reaction rate constants for these important combustion reactions. Experimental work at Brown University on the effect of reaction on the structural evolution of different chars (i.e., phenolic resin char and chars produced from three different coals) have been investigated in a TGA/TPD-MS system. It has been found that samples of different age of these chars appeared to lose their "memory" concerning their initial structures at high burn-offs. During the reporting period, thermal desorption experiments of selected samples were conducted. These spectra show that the population of low temperature oxygen surface complexes, which are primarily responsible for reactivity, are more similar for the high burn-off than for the low burn-off samples of different ages; i.e., the population of active sites are more

  12. Influence of pyrolysis conditions on the structure and gasification reactivity of biomass chars

    Energy Technology Data Exchange (ETDEWEB)

    E. Cetin; B. Moghtaderi; R. Gupta; T.F. Wall [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2004-11-01

    The physical and chemical structure as well as gasification reactivities of chars generated from several biomass species (i.e. pinus radiata, eucalyptus maculata and sugar cane bagasse) were studied to gain insight into the role of heating rate and pressure on the gasification characteristics of biomass chars. Char samples were generated in a suite of reactors including a wire mesh reactor, a tubular reactor, and a drop tube furnace. Scanning electron microscopy analysis, X-ray diffractometry, digital cinematography and surface area analysis were employed to determine the impact of operating conditions on the char structure. The global gasification reactivities of char samples were also determined for a range of pressures between 1 and 20 bar using pressurised thermogravimetric analysis technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. It was found that under high heating rates the char particles underwent plastic deformation (i.e. melted) developing a structure different to that of the virgin biomass. Pressure was also found to influence the physical and chemical structures of char particles. The difference in the gasification reactivities of biomass chars at pressure was found to correlate well with the effect of pyrolysis pressure on the graphitisation process in the biomass char structure. 29 refs., 18 figs., 2 tabs.

  13. Char crystalline transformations during coal combustion and their implications for carbon burnout

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.H.

    1999-07-07

    Residual, or unburned carbon in fly ash affects many aspects of power plant performance and economy including boiler efficiency, electrostatic precipitator operation, and ash as a salable byproduct. There is a large concern in industry on the unburned carbon problem due to a variety of factors, including low-NOx combustion system and internationalization of the coal market. In recent work, it has been found that residual carbon extracted from fly ash is much less reactive than the laboratory chars on which the current kinetics are based. It has been suggested that thermal deactivation at the peak temperature in combustion is a likely phenomenon and that the structural ordering is one key mechanism. The general phenomenon of carbon thermal annealing is well known, but there is a critical need for more data on the temperature and time scale of interest to combustion. In addition, high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars, has become available. Motivated by these new developments, this University Coal Research project has been initiated with the following goals: (1) To determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history. (2) To characterize the effect of the thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis.

  14. Char crystalline transformations during coal combustion and their implications for carbon burnout

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.H.

    1999-03-11

    Residual, or unburned carbon in fly ash affects many aspects of power plant performance and economy including boiler efficiency, electrostatic precipitator operation, and ash as a salable byproduct. There is a large concern in industry on the unburned carbon problem due to a variety of factors, including low-NOx combustion system and internationalization of the coal market. In recent work, it has been found that residual carbon extracted from fly ash is much less reactive than the laboratory chars on which the current kinetics are based. It has been suggested that thermal deactivation at the peak temperature in combustion is a likely phenomenon and that the structural ordering is one key mechanism. The general phenomenon of carbon thermal annealing is well known, but there is a critical need for more data on the temperature and time scale of interest to combustion. In addition, high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars, has become available. Motivated by these new developments, this University Coal Research project has been initiated with the following goals: to determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history; and to characterize the effect of this thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis.

  15. Numerical prediction of unburned carbon levels in large pulverized coal utility boilers

    Energy Technology Data Exchange (ETDEWEB)

    Javier Pallares; Inmaculada Arauzo; Luis Ignacio Diez [University of Zaragoza, Zaragoza (Spain). Centre of Research for Energy Resources and Consumptions (CIRCE), Thermal Division

    2005-12-01

    Advanced combustion kinetics models are of widespread use to predict carbon losses from coal combustion. However, those models cannot completely capture the complexity of the real phenomena affecting the fluid flow in a full-scale utility boiler, such as burner-to-burner interactions and bottom hopper vortexes or reversed-flows, and usually underpredict carbon in ash values. The use of CFD codes offers a more detailed treatment of the fluid dynamics involved in the boiler. However, most of them do not incorporate advanced kinetics submodels for char oxidation. In this paper, rank-dependent correlations and ash inhibition submodel have been coupled to a commercial CFD code, significantly improving carbon in ash predictions. Results from the simulation of the ASM Brescia power plant (Italy) for three different South-American coals are compared against plant laboratory values, using either the popular single film combustion model or the modified combustion model discussed in this paper. 24 refs., 7 figs., 6 tabs.

  16. Understanding how lake populations of arctic char are structured and function with special consideration of the potential effects of climate change: A multi-faceted approach.

    Science.gov (United States)

    Budy, Phaedra; Luecke, Chris

    2014-01-01

    Size dimorphism in fish populations, both its causes and consequences, has been an area of considerable focus; however, uncertainty remains whether size dimorphism is dynamic or stabilizing and about the role of exogenous factors. Here, we explored patterns among empirical vital rates, population structure, abundance and trend, and predicted the effects of climate change on populations of arctic char (Salvelinus alpinus) in two lakes. Both populations cycle dramatically between dominance by small (≤300 mm) and large (>300 mm) char. Apparent survival (Φ) and specific growth rates (SGR) were relatively high (40–96 %; SGR range 0.03–1.5 %) and comparable to those of conspecifics at lower latitudes. Climate change scenarios mimicked observed patterns of warming and resulted in temperatures closer to optimal for char growth (15.15 °C) and a longer growing season. An increase in consumption rates (28–34 %) under climate change scenarios led to much greater growth rates (23–34 %). Higher growth rates predicted under climate change resulted in an even greater predicted amplitude of cycles in population structure as well as an increase in reproductive output (Ro) and decrease in generation time (Go). Collectively, these results indicate arctic char populations (not just individuals) are extremely sensitive to small changes in the number of ice-free days. We hypothesize years with a longer growing season, predicted to occur more often under climate change, produce elevated growth rates of small char and act in a manner similar to a “resource pulse,” allowing a sub-set of small char to “break through,” thus setting the cycle in population structure.

  17. Preliminary report on the flow no-flow indicator for the BI-GAS char line

    Energy Technology Data Exchange (ETDEWEB)

    Roach, P. D.; Raptis, A. C.

    1978-07-01

    The BI-GAS coal gasification pilot plant at Homer City, Pa. has an urgent need for monitoring char flow to the gasifier. The feed lines contain finely divided char in a steam carrier and operate at 800/sup 0/F and 1650 psi. A high temperature microphone, developed at ANL, has been installed in one char feed line with the goal of distinguishing between flow and no-flow conditions. The microphone signal is amplified and spectrum analyzed to reveal signal components associated with both char flow and steam flow. So far, we have obtained data only on the background steam noise, because operational problems at the pilot plant have delayed the start of char flow since our microphone was installed. The steam flow provides a strong microphone signal with a rich spectral content extending to about 45 kHz. Char flow data are scheduled to be taken during summer 1978.

  18. [Configuration of pyrolytic chars from waste tires in fluidized bed reactor].

    Science.gov (United States)

    Jin, Yu-qi; Yan, Jian-hua; Gu, Jie-yuan; Cen, Ke-fa

    2004-11-01

    With the fluidized bed as main reactor, the configuration of chars of waste tire was investigated. The change of specific surface area, porosity and specific pore volume of chars received at various temperature, diameter of bed materials and superficial fluidization number was mainly researched. The specific surface area and porosity of chars had the peak value at 650 degrees C or 750 degrees C, which showed there exists the best pyrolysis temperature from the angle of char quality and it will decrease with smaller diameter of bed materials, 0.135-0.304mm. The porosity of chars decreases with the fluidization number increasing. The change tendency of the specific surface area of chars with the fluidization number is correlated with the pyrolysis temperature. At 550 degrees C the specific surface area of chars decreases with the fluidization number increasing, while at 650 degrees C the other way round. The change tendency of the specific pore volume of chars with the temperature is correlated with the diameter of bed materials. With larger bed materials (0.304-0.4mm), the specific pore volume of chars rises at fisrt, then decreases with the temperature increasing, and with smaller bed materials, it decreases with the temperature increasing.

  19. A volumetric ablation model of EPDM considering complex physicochemical process in porous structure of char layer

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2017-06-01

    Full Text Available A volumetric ablation model for EPDM (ethylene- propylene-diene monomer is established in this paper. This model considers the complex physicochemical process in the porous structure of a char layer. An ablation physics model based on a porous structure of a char layer and another model of heterogeneous volumetric ablation char layer physics are then built. In the model, porosity is used to describe the porous structure of a char layer. Gas diffusion and chemical reactions are introduced to the entire porous structure. Through detailed formation analysis, the causes of the compact or loose structure in the char layer and chemical vapor deposition (CVD reaction between pyrolysis gas and char layer skeleton are introduced. The Arrhenius formula is adopted to determine the methods for calculating carbon deposition rate C which is the consumption rate caused by thermochemical reactions in the char layer, and porosity evolution. The critical porosity value is used as a criterion for char layer porous structure failure under gas flow and particle erosion. This critical porosity value is obtained by fitting experimental parameters and surface porosity of the char layer. Linear ablation and mass ablation rates are confirmed with the critical porosity value. Results of linear ablation and mass ablation rate calculations generally coincide with experimental results, suggesting that the ablation analysis proposed in this paper can accurately reflect practical situations and that the physics and mathematics models built are accurate and reasonable.

  20. A volumetric ablation model of EPDM considering complex physicochemical process in porous structure of char layer

    Science.gov (United States)

    Yang, Liu; Xiao-Jing, Yu; Jian-Ming, Ma; Yi-Wen, Guan; Jiang, Li; Qiang, Li; Sa, Yang

    2017-06-01

    A volumetric ablation model for EPDM (ethylene- propylene-diene monomer) is established in this paper. This model considers the complex physicochemical process in the porous structure of a char layer. An ablation physics model based on a porous structure of a char layer and another model of heterogeneous volumetric ablation char layer physics are then built. In the model, porosity is used to describe the porous structure of a char layer. Gas diffusion and chemical reactions are introduced to the entire porous structure. Through detailed formation analysis, the causes of the compact or loose structure in the char layer and chemical vapor deposition (CVD) reaction between pyrolysis gas and char layer skeleton are introduced. The Arrhenius formula is adopted to determine the methods for calculating carbon deposition rate C which is the consumption rate caused by thermochemical reactions in the char layer, and porosity evolution. The critical porosity value is used as a criterion for char layer porous structure failure under gas flow and particle erosion. This critical porosity value is obtained by fitting experimental parameters and surface porosity of the char layer. Linear ablation and mass ablation rates are confirmed with the critical porosity value. Results of linear ablation and mass ablation rate calculations generally coincide with experimental results, suggesting that the ablation analysis proposed in this paper can accurately reflect practical situations and that the physics and mathematics models built are accurate and reasonable.

  1. Is this charred material from a VHS video cassette?

    Science.gov (United States)

    Fruchtenicht, Tara; Blackledge, Robert D.; Williams, Teresa R.

    2010-06-01

    At his residence, a victim in a double homicide had installed a home-built video surveillance system. The suspects either knew of or discovered this system and removed it. In a backyard at a location associated with the suspects was a barrel used for burning trash. Could charred debris recovered from a metal bowl found among the contents of the barrel be the remains of a VHS video cassette? A positive answer to the question was obtained through a combination of optical microscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Energy Dispersive Spectroscopy (EDS).

  2. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  3. Bone char quality and defluoridation capacity in contact precipitation

    DEFF Research Database (Denmark)

    Albertus, J.; Bregnhøj, Henrik; Kongpun, M.

    2002-01-01

    Samples from six different brands of bone char are tested for their capacity to remove fluoride from water in batch. Initial concentrations of 10 mg/L and contact times of 6 hours are used. The removal capacities observed are 0.6-1.1 mg/g on an average, s.d. being 0.16. Addition of calcium...... and phosphate compounds to the jar experiments results in more than doubling of these capacities, on average 1.9 mg/g, s.d. being 0.14. One of bone char products is setup in columns are fed with water, 100 mg/L, for saturation. Hereafter the coloumns are fed with water of 10 mgF/L where calcium and phosphate...... are added as in the contact precipitation process. The results show that the columns are able to remove up to 700 bedvolumes, before the concentration of fluoride in the effluent water breaks through, above 1.5 mg/L. Operational removal capacities observed are 7 and 9 mg/L, depending on contact time...

  4. Biomass Chars: The Effects of Pyrolysis Conditions on Their Morphology, Structure, Chemical Properties and Reactivity

    Directory of Open Access Journals (Sweden)

    Chamseddine Guizani

    2017-06-01

    Full Text Available Solid char is a product of biomass pyrolysis. It contains a high proportion of carbon, and lower contents of H, O and minerals. This char can have different valorization pathways such as combustion for heat and power, gasification for Syngas production, activation for adsorption applications, or use as a soil amendment. The optimal recovery pathway of the char depends highly on its physical and chemical characteristics. In this study, different chars were prepared from beech wood particles under various pyrolysis operating conditions in an entrained flow reactor (500–1400 °C. Their structural, morphological, surface chemistry properties, as well as their chemical compositions, were determined using different analytical techniques, including elementary analysis, Scanning Electronic Microscopy (SEM coupled with an energy dispersive X-ray spectrometer (EDX, Fourier Transform Infra-Red spectroscopy (FTIR, and Raman Spectroscopy. The biomass char reactivity was evaluated in air using thermogravimetric analysis (TGA. The yield, chemical composition, surface chemistry, structure, morphology and reactivity of the chars were highly affected by the pyrolysis temperature. In addition, some of these properties related to the char structure and chemical composition were found to be correlated to the char reactivity.

  5. Formation of nanocarbon spheres by thermal treatment of woody char from fast pyrolysis process

    Science.gov (United States)

    Qiangu Yan; Hossein Toghiani; Zhiyong Cai; Jilei Zhang

    2014-01-01

    Influences of thermal treatment conditions of temperature, reaction cycle and time, and purge gas type on nanocarbon formation over bio-chars from fast pyrolysis and effects of thermal reaction cycle and purge gas type on bio-char surface functional groups were investigated by temperature-programmed desorption (TPD) and temperature programmed reduction methods....

  6. Single char particle model for naphthalene reduction in a biomass gasification system

    NARCIS (Netherlands)

    Abu El-Rub, Ziad; Brem, Gerrit; Bramer, Eduard A.

    2015-01-01

    Tar removal in biomass gasification systems is one of the key challenges to overcome for the successful commercialization of this technology. This study focused on tar conversion over the active char particle besides the simultaneous carbon conversion of the char particle. In the presented model,

  7. Digital image processing applications in the ignition and combustion of char/coal particles

    Energy Technology Data Exchange (ETDEWEB)

    Annamalai, K.; Kharbat, E.; Goplakrishnan, C.

    1992-12-01

    Digital image processing, is employed in this remarch study in order to visually investigate the ignition and combustion characteristics of isolated char/coal particles as well as the effect of interactivecombustion in two-particle char/coal arrays. Preliminary experiments are conducted on miniature isolated candles as well as two-candle arrays.

  8. Oxy-fuel combustion of millimeter-sized coal char: Particle temperatures and NO formation

    DEFF Research Database (Denmark)

    Brix, Jacob; Navascués, Leyre Gómez; Nielsen, Joachim Bachmann

    2013-01-01

    coal char and lignite char, respectively, cannot be fully explained. Char/NO interactions appear to be quite complex, and mineral catalysis and release to the gas-phase of volatile N-species such as HCN, either from secondary pyrolysis or as a product of the char–N + O2 reaction, may play a role.......In this work, differences in particle temperature and NO yield during char oxidation in O2/N2 and O2/CO2 atmospheres, respectively, have been examined. A laboratory scale fixed bed reactor, operated isothermally at 1073 K, was used for combustion of millimeter-sized lignite and bituminous coal char...... increased with mass loading, by as much as 700 K above the furnace set point. The formation of NO from lignite char was not influenced by the change from N2 to CO2 whereas the NO yield from bituminous coal char was considerably lower in O2/CO2 compared O2/N2. For both chars the conversion to NO decreased...

  9. Electron paramagnetic resonance and dynamic nuclear polarization of char suspensions: surface science and oximetry

    DEFF Research Database (Denmark)

    Clarkson, R B; Odintsov, B M; Ceroke, P J

    1998-01-01

    Carbon chars have been synthesized in our laboratory from a variety of starting materials, by means of a highly controlled pyrolysis technique. These chars exhibit electron paramagnetic resonance (EPR) line shapes which change with the local oxygen concentration in a reproducible and stable fashion...

  10. Modeling char conversion under suspension fired conditions in O2/N2 and O2/CO2 atmospheres

    DEFF Research Database (Denmark)

    Brix, Jacob; Jensen, Peter Arendt; Jensen, Anker Degn

    2011-01-01

    concentrations between 5 and 28 vol.%. The COal COmbustion MOdel, COCOMO, includes the three char morphologies: cenospheric char, network char and dense char each divided between six discrete particle sizes. Both combustion and gasification with CO2 are accounted for and reaction rates include thermal char...... deactivation, which was found to be important for combustion at high reactor temperatures and high O2 concentrations. COCOMO show in general good agreement with experimental char conversion profiles at conditions covering zone I–III. From the experimental profiles no effect of CO2 gasification on char...... conversion has been found. COCOMO does however suggest that CO2 gasification in oxy-fuel combustion at low O2 concentrations can account for as much as 70% of the overall char consumption rate during combustion in zone III....

  11. Degradation of p-Nitrophenol by Lignin and Cellulose Chars: H2O2-Mediated Reaction and Direct Reaction with the Char.

    Science.gov (United States)

    Yang, Jing; Pignatello, Joseph J; Pan, Bo; Xing, Baoshan

    2017-08-15

    Chars and other black carbons are reactive toward certain compounds. Such reactivity has been attributed to reduction of O2 by persistent free radicals in the solid to H2O2, which then back-reacts with the solid to generate reactive oxygen species (ROS; especially HO•). We studied the decomposition of p-nitrophenol (PNP) by pure lignin and cellulose chars aged in moist air or a vacuum at room temperature for up to a month. In air, the chars chemisorbed oxygen, a portion of which was liberated as H2O2 when the char was submerged in water. The evolved H2O2 was simultaneously decomposed by the char. PNP reacted predominantly in the sorbed state and only reduction products (phenol, catechol) were identified. Aging the char in air sharply (within hours) reduced H2O2-producing capacity and free radical concentration, but more gradually reduced PNP decay rate over the month-long period. PNP decay was only modestly suppressed (12-30%) by H2O2 removal (catalase), and had little effect on the free radical signal (H2O2-dependent reactions, and the vast majority of direct-reacting sites are nonradical in character. Nonradical sites are also responsible in part for H2O2 decomposition; in fact, H2O2 pretreatment depleted PNP reactive sites. Lignin char was generally more reactive than cellulose char. The Fe impurity in lignin played no role. The results are relevant to the fate of pollutants in black carbon-rich environments and the use of carbons in remediation.

  12. Fast pyrolysis char - Assessment of alternative uses within the bioliq® concept.

    Science.gov (United States)

    Funke, A; Niebel, A; Richter, D; Abbas, M M; Müller, A-K; Radloff, S; Paneru, M; Maier, J; Dahmen, N; Sauer, J

    2016-01-01

    Experiments with a process development unit for fast pyrolysis of biomass residues of 10kgh(-1) have been performed to quantify the impact of two different product recovery options. Wheat straw, miscanthus and scrap wood have been used as feedstock. A separate recovery of char increases the organic oil yield as compared to a combined recovery of char and organic condensate (OC). Furthermore, it allows for an alternative use of the byproduct char which represents an important product fraction for the high ash biomass residues under consideration. The char produced shows little advantage over its biomass precursor when considered as energy carrier due to its high ash content. Significant value can be added by demineralizing and activating the char. The potential to increase the economic feasibility of fast pyrolysis is shown by an assessment of the bioliq® process chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Kinetics of coal combustion: Part 3, Mechanisms and kinetics of char combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gavalas, G. R.; Flagan, R. C. [California Inst. of Tech., Pasadena, CA (USA)

    1988-09-01

    This report summarizes a three-year research program aimed at developing this level of understanding of char combustion through a combination of detailed analysis of chars as produced during devolatilization and as they evolve during oxidation, and theoretical studies of the porous microstructures and of pore diffusion and reaction within the coal particles. A small number of coals have been studied in detail, namely a HVA bituminous (PSOC 1451), a sub-bituminous (PSOC 1488), and a lignite (PSOC 1443). Chars have been generated from size-classified samples of these coals by pyrolysis in an inert atmosphere in a drop tube furnace. The chars were then characterized both chemically and physically. Subsequent oxidation studies were performed on these chars. 42 refs., 54 figs., 4 tabs.

  14. Chemical and Isotopic Thresholds in Charring: Implications for the Interpretation of Charcoal Mass and Isotopic Data

    Science.gov (United States)

    Pyle, L.; Hockaday, W. C.; Boutton, T. W.; Zygourakis, K.; Kinney, T.; Masiello, C. A.

    2014-12-01

    Charcoal plays a significant role in the long-term carbon cycle and its use as a soil amendment is becoming a viable carbon sequestration strategy (biochar). One challenge in this research area has been comparing results between studies in part due to the diversity of lab and field production conditions. Although the highest treatment temperature (HTT) is often used to describe pyrolysis conditions, several studies have shown that length of time at the highest temperature can also cause changes to the physicochemical qualities of charcoal and ignoring this effect may introduce inter-comparison problems. Addressing this issue becomes especially important in the discussion of optimizing biochar for soil remediation and carbon sequestration, and in discussions of charcoal use in reconstructing past fire regimes, as increasing time at temperature may cause changes in charcoal properties similar to the changes caused by increasing HTT. Here we introduce a formal definition of charring intensity (CI) to more accurately characterize pyrolysis, and we document variation in this property with pyrolysis temperature and reaction duration. We found two types of responses to CI: either a linear or a threshold relationship. We show that a threshold exists where %C, %N and δ15N begin exhibiting large changes, and this CI threshold co-occurred with an increase in charcoal aromaticity. Mass yield decreased linearly with charring intensity and carbon isotopes did not change from original biomass values in our controlled laboratory experiments. Analysis of these data shows that pyrolysis parameters should be defined in the literature as a combination of temperature and duration conditions, and that biomass that has undergone pyrolysis may be influencing soil organic nitrogen. Additionally, the lack of alteration in carbon isotopes across our matrix supports the efficacy of using pyrolyzed material for archaeological reconstructions.

  15. Food-chain and dose submodel, CALDOS, for the assessment of Canada's nuclear fuel waste management concept. AECL research No. AECL-10165

    Energy Technology Data Exchange (ETDEWEB)

    Zach, R.; Sheppard, S.C.

    1992-01-01

    The food-chain and dose submodel, CALDOS, for assessing Canada's nuclear fuel waste management concept of disposal in a vault deep in the Canadian Shield is presented. Together with the surface water, soil and atmosphere submodels, CALDOS is integrated into a comprehensive, probabilistic biosphere model for post-closure assessment. This model is representative of the Canadian Shield in Ontario and CALDOS is fully generic. The model has numerous parameters and some of them are element-, radionuclide- or food-type-specific. Results of a sensitivity analysis are used to assess parameter importance in dose prediction. Quality assurance is addressed through general literature, model and parameter evaluations, specifically designed for environmental assessment models.

  16. How much detail and accuracy is required in plant growth sub-models to address questions about optimal management strategies in agricultural systems?

    Science.gov (United States)

    Renton, Michael

    2011-01-01

    Background and aims Simulations that integrate sub-models of important biological processes can be used to ask questions about optimal management strategies in agricultural and ecological systems. Building sub-models with more detail and aiming for greater accuracy and realism may seem attractive, but is likely to be more expensive and time-consuming and result in more complicated models that lack transparency. This paper illustrates a general integrated approach for constructing models of agricultural and ecological systems that is based on the principle of starting simple and then directly testing for the need to add additional detail and complexity. Methodology The approach is demonstrated using LUSO (Land Use Sequence Optimizer), an agricultural system analysis framework based on simulation and optimization. A simple sensitivity analysis and functional perturbation analysis is used to test to what extent LUSO's crop–weed competition sub-model affects the answers to a number of questions at the scale of the whole farming system regarding optimal land-use sequencing strategies and resulting profitability. Principal results The need for accuracy in the crop–weed competition sub-model within LUSO depended to a small extent on the parameter being varied, but more importantly and interestingly on the type of question being addressed with the model. Only a small part of the crop–weed competition model actually affects the answers to these questions. Conclusions This study illustrates an example application of the proposed integrated approach for constructing models of agricultural and ecological systems based on testing whether complexity needs to be added to address particular questions of interest. We conclude that this example clearly demonstrates the potential value of the general approach. Advantages of this approach include minimizing costs and resources required for model construction, keeping models transparent and easy to analyse, and ensuring the model

  17. Syntheses of Families of Enantiopure and Diastereopure Cobalt Catalysts Derived from Trications of the Formula [Co(NH2CHArCHArNH2)3](3).

    Science.gov (United States)

    Ghosh, Subrata K; Lewis, Kyle G; Kumar, Anil; Gladysz, John A

    2017-02-20

    Aerobic reactions of CoX2 (X = OAc, Cl) or Co(ClO4)2 with (S,S)-1,2-diphenylethylenediamine [(S,S)-dpen] in CH3OH, followed by HCl or HClO4 additions, give the diastereomeric lipophobic salts Λ-[Co((S,S)-dpen)3](3+)3Cl(-) [Λ-(S,S)-1(3+)3Cl(-)] or Δ-(S,S)-1(3+)3ClO4(-) (60-65%) with high degrees of selectivity. Anion metatheses (room temperature) and equilibrations (charcoal, CH3OH, 70 °C) show that the former is more stable than Δ-(S,S)-1(3+)3Cl(-), and the latter is more stable than Λ-(S,S)-1(3+)3ClO4(-). Additional anion metatheses lead to large families of lipophilic salts Λ- and Δ-(S,S)-1(3+)2X(-)X'(-) [X/X' = Cl/BArf [BArf = B(3,5-C6H3(CF3)2)4], PF6/BArf, BF4/BArf, PhBF3/BArf, Cl/BArf20 [BArf20 = B(C6F5)4], BArf/BArf, BArf20/BArf20, BF4/BF4, PF6/PF6]. Mixed salts of the formula Λ- and Δ-[Co((S,S)-NH2CHArCHArNH2)3](3+)2Cl(-)BArf(-) are similarly prepared (Ar = 4-C6H4n-Bu, 4-C6H4Cl, 4-C6H4CF3, 4-C6H4OCH3, α-naphthyl, β-naphthyl, 2-C6H4OBn). The diastereotopic NHH' protons exhibit different (1)H NMR signals; one shifts far downfield when X/X' = Cl/BArf (δ ca. 8.0 vs 4.0 ppm). This is believed to arise from hydrogen bonding between the two Cl(-) anions and the two C3 faces of the D3-symmetric trication, each of which feature three synperiplanar NH groups. When all of the anions are poor hydrogen-bond acceptors (e.g., BArf(-), BF4(-), ClO4(-)), equilibria favor Δ diastereomers.

  18. The removal of reactive dyes using high-ash char

    Directory of Open Access Journals (Sweden)

    Moreira R.F.P.M.

    2001-01-01

    Full Text Available The thermodynamics and kinetics of adsorption of reactive dyes on high-ash char was studied. Equilibrium data were obtained using the static method with controlled agitation at temperatures in the range of 30 to 60ºC. The Langmuir isotherm model was used to describe the equilibrium of adsorption, and the equilibrium parameters, R L, in the range of 0 to 1 indicate favorable adsorption. The amount of dye adsorbed increased as temperature increased from 30 to 40ºC, but above 40ºC the increase in temperature resulted in a decrease in the amount of dye adsorbed. The kinetic data presented are for controlled agitation at 50 rpm and constant temperature with dye concentrations in the range of 10 ppm to50 ppm. The film mass transfer coefficient, Kf, and the effective diffusivity inside the particle, De, were fitted to the experimental data. The results indicate that internal diffusion governs the adsorption rate.

  19. BONE CHAR BASED BUCKET DEFLUORIDATOR IN TANZANIAN HOUSEHOLDS

    DEFF Research Database (Denmark)

    Jacobsen, P.; Dahi, Elian

    1997-01-01

    A household defluoridator, made of a 20 L plastic bucket and 10 kg of bone char, is tested and found efficient to remove fluoride at a capacity of 1.1 mg/g. On an average, the defluoridator reduced the original contents of 8.5 mgF/L to 0.37 mgF/L, i.e. 95.6 %, for a period of 2 months, where 32.5 L...... were treated every day. The defluoridator could be manufactured locally in Ngurdoto village, Arusha Region Tanzania for a price of about 10 US $ per unit. The defluoridator is monitored as operated in 10 households. The defluoridator reduced the fluoride concentration from 10.5 mg/L to less than 1 mg....../L for periods between 4 and 13 months. The users expressed their acceptability of the defluoridator and its performance....

  20. Properties of pyrolytic chars and activated carbons derived from pilot-scale pyrolysis of used tires.

    Science.gov (United States)

    Li, S Q; Yao, Q; Wen, S E; Chi, Y; Yan, J H

    2005-09-01

    Used tires were pyrolyzed in a pilot-scale quasi-inert rotary kiln. Influences of variables, such as time, temperature, and agent flow, on the activation of obtained char were subsequently investigated in a laboratory-scale fixed bed. Mesoporous pores are found to be dominant in the pore structures of raw char. Brunauer-Emmett-Teller (BET) surfaces of activated chars increased linearly with carbon burnoff. The carbon burnoff of tire char achieved by carbon dioxide (CO2) under otherwise identical conditions was on average 75% of that achieved by steam, but their BET surfaces are almost the same. The proper activation greatly improved the aqueous adsorption of raw char, especially for small molecular adsorbates, for example, phenol from 6 to 51 mg/g. With increasing burnoff, phenol adsorption exhibited a first-stage linear increase followed by a rapid drop after 30% burnoff. Similarly, iodine adsorption first increased linearly, but it held as the burnoff exceeded 40%, which implied that the reduction of iodine adsorption due to decreasing micropores was partially made up by increasing mesopores. Both raw chars and activated chars showed appreciable adsorption capacity of methylene-blue comparable with that of commercial carbons. Thus, tire-derived activated carbons can be used as an excellent mesoporous adsorbent for larger molecular species.

  1. Effects of Biomass Feedstocks and Gasification Conditions on the Physiochemical Properties of Char

    Directory of Open Access Journals (Sweden)

    Raymond L. Huhnke

    2013-08-01

    Full Text Available Char is a low-value byproduct of biomass gasification and pyrolysis with many potential applications, such as soil amendment and the synthesis of activated carbon and carbon-based catalysts. Considering these high-value applications, char could provide economic benefits to a biorefinery utilizing gasification or pyrolysis technologies. However, the properties of char depend heavily on biomass feedstock, gasifier design and operating conditions. This paper reports the effects of biomass type (switchgrass, sorghum straw and red cedar and equivalence ratio (0.20, 0.25 and 0.28, i.e., the ratio of air supply relative to the air that is required for stoichiometric combustion of biomass, on the physiochemical properties of char derived from gasification. Results show that the Brunauer-Emmett-Teller (BET surface areas of most of the char were 1–10 m2/g and increased as the equivalence ratio increased. Char moisture and fixed carbon contents decreased while ash content increased as equivalence ratio increased. The corresponding Fourier Transform Infrared spectra showed that the surface functional groups of char differed between biomass types but remained similar with change in equivalence ratio.

  2. Leaching behaviour and ecotoxicity evaluation of chars from the pyrolysis of forestry biomass and polymeric materials.

    Science.gov (United States)

    Bernardo, M; Mendes, S; Lapa, N; Gonçalves, M; Mendes, B; Pinto, F; Lopes, H

    2014-09-01

    The main objective of this study was to assess the environmental risk of chars derived from the pyrolysis of mixtures of pine, plastics, and scrap tires, by studying their leaching potential and ecotoxicity. Relationships between chemical composition and ecotoxicity were established to identify contaminants responsible for toxicity. Since metallic contaminants were the focus of the present study, an EDTA washing step was applied to the chars to selectively remove metals that can be responsible for the observed toxicity. The results indicated that the introduction of biomass to the pyrolysis feedstock enhanced the acidity of chars and promote the mobilisation of inorganic compounds. Chars resulting from the pyrolysis of blends of pine and plastics did not produce ecotoxic eluates. A relationship between zinc concentrations in eluates and their ecotoxicity was found for chars obtained from mixtures with tires. A significant reduction in ecotoxicity was found when the chars were treated with EDTA, which was due to a significant reduction in zinc in chars after EDTA washing. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Coal devolatilization and char conversion under suspension fired conditions in O2/N2 and O2/CO2 atmospheres

    DEFF Research Database (Denmark)

    Jensen, Anker Degn; Brix, Jacob; Jensen, Peter Arendt

    2010-01-01

    have been carried out in an electrically heated entrained flow reactor that is designed to simulate the conditions in a suspension fired boiler. Coal devolatilized in N2 and CO2 atmospheres provided similar results regarding char morphology, char N2-BET surface area and volatile yield. This strongly...... indicates that a shift from air to oxy-fuel combustion does not influence the devolatilization process significantly. Char combustion experiments yielded similar char conversion profiles when N2 was replaced with CO2 under conditions where combustion was primarily controlled by chemical kinetics. When char...

  4. CO2 gasification reactivity of biomass char: catalytic influence of alkali, alkaline earth and transition metal salts.

    Science.gov (United States)

    Lahijani, Pooya; Zainal, Zainal Alimuddin; Mohamed, Abdul Rahman; Mohammadi, Maedeh

    2013-09-01

    This study investigates the influence of alkali (Na, K), alkaline earth (Ca, Mg) and transition (Fe) metal nitrates on CO2 gasification reactivity of pistachio nut shell (PNS) char. The preliminary gasification experiments were performed in thermogravimetric analyzer (TGA) and the results showed considerable improvement in carbon conversion; Na-char>Ca-char>Fe-char>K-char>Mg-char>raw char. Based on TGA studies, NaNO3 (with loadings of 3-7 wt%) was selected as the superior catalyst for further gasification studies in bench-scale reactor; the highest reactivity was devoted to 5 wt% Na loaded char. The data acquired for gasification rate of catalyzed char were fitted with several kinetic models, among which, random pore model was adopted as the best model. Based on obtained gasification rate constant and using the Arrhenius plot, activation energy of 5 wt% Na loaded char was calculated as 151.46 kJ/mol which was 53 kJ/mol lower than that of un-catalyzed char. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2013-01-01

    , char properties, measured at room temperature, were dependent on the preceding storage conditions (in air or in a desiccator). The char was found to have the highest mechanical strength against compression in the outer crust facing the heat source. For thin (147μm) free coating films, a tendency...... with respect to the mechanical resistance against compression, degree of expansion, and residual mass fraction. Experimental results show that when using this type of shock heating, the mechanical resistance of the char against compression cannot meaningfully be correlated to the expansion factor. In addition...

  6. Chemical Characterization of Pineapple Leaf Residue Chars generated by Controlled Combustion and by open burning

    Directory of Open Access Journals (Sweden)

    Leng L.Y.

    2017-01-01

    Full Text Available This study was undertaken to compare the chemical characteristics of pineapple leave residues (PLRs char generated by controlled combustion and by open burning. The properties of char generated by control combustion (CC and open burning (OB varied, due to differences in the production process. The total N, K and surface area of the char generated by CC were significantly higher than the OB. The results indicate that the CC process was better to be applied as a soil amendment than was the OB process.

  7. History, Violence and Poetics: Saint-John Perse and René Char

    Directory of Open Access Journals (Sweden)

    Nathan Bracher

    1991-06-01

    Full Text Available This essay explores the parallel yet opposite stances taken both personally and textually by Perse and Char with respect to drama of World War II. While Perse remained disdainfully aloof from public affairs after the defeat and proclaimed in his poetry his solidarity with all humanity, Char explicitly linked his writing to events, yet sought to create a human space removed from history's upheavals. Striving to transcend the vicissitudes of individual existence, Perse celebrates an epic vision of history that overlooks and even condones its violence. Focusing on the inconsistent, fragmentary nature of existence, Char prevents us from having any teleological delusions concerning war.

  8. Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn

    2016-01-01

    Fast pyrolysis of wheat straw and rice husk was carried out in an entrained flow reactor at hightemperatures(1000e1500) C. The collected char was analyzed using X-ray diffractometry, N2-adsorption,scanning electron microscopy, particle size analysis with CAMSIZER XT, 29Si and 13C solid......-statenuclear magnetic resonance spectroscopy and thermogravimetric analysis to investigate the effect ofinorganic matter on the char morphology and oxygen reactivity. The silicon compounds were dispersedthroughout the turbostratic structure of rice husk char in an amorphous phase with a low meltingtemperature (z730 C......), which led to the formation of a glassy char shell, resulting in a preserved particlesize and shape of chars. The high alkali content in the wheat straw resulted in higher char reactivity,whereas the lower silicon content caused variations in the char shape from cylindrical to near...

  9. Investigation of the Anisotropic Behavior of Wood Char Particles during Gasification

    DEFF Research Database (Denmark)

    Henriksen, Ulrik Birk; Hindsgaul, Claus; Qvale, Einar Bjørn

    2006-01-01

    (R) and tangential (T) directions. Despite this, this property has normally not been included in mathematical model descriptions of gasification of thermally thick particles. The present paper describes a study of the influence of the anisotropy on the reactivity of thermally thick char particles...... during gasification of wood using macro TGA equipment. The char particles, in the form of slabs (approximately 50 × 70 × 10 mm), were produced by pyrolysis of wood slabs that had been cut from the trunk of beech trees. The char slabs were grouped into three categories according to the orientation...... of the normal to the greater surface of the slabs L, R, or T (see Figure 8). When the smaller surfaces were coated with alumina silicate, the gasification agent could only enter the interior of the slabs through the greater surfaces. Thermally thick char particles from beech and pine reacted more slowly...

  10. Charred body: virtual autopsy with multi-slice computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Thali, Michael J; Yen, Kathrin; Plattner, Thomas; Schweitzer, Wolf; Vock, Peter; Ozdoba, Christoph; Dirnhofer, Richard

    2002-11-01

    The correct examination of a charred body is a forensic challenge. Examination, interpretation, and conclusion in respect to identification, vital reactions, toxicological analysis, and determining cause and manner of death are all more difficult than without burns. To evaluate what can be seen in the case of a charred body, we made an examination with the new radiological modalities of cross-section techniques, via multi-slice Computed Tomography (MSCT) and Magnetic Resonance Imaging (MRI), prior to performing the classical forensic autopsy. In a charred body case of a single motor vehicle/fixed object collision with a post crash fire, the radiological methods of MSCT and MRI made it possible to document the injuries caused by burn as well as the forensic relevant vital reactions (air embolism and blood aspiration). In conclusion, we think postmortem imaging is a good forensic visualization tool with a great potential for the forensic documentation and examination of charred bodies.

  11. The different effects of applying fresh, composted or charred manure on soil N2O emissions

    DEFF Research Database (Denmark)

    Zhu, Kun; Christel, Wibke; Bruun, Sander

    2014-01-01

    to higher N2O and CO2 emissions than heterogeneous distribution. However, the effect of different distribution modes was not significant in treatments with charred manure, since N turnover in the immature compost was much more active than that in the charred manure. By combining charred manure...... with composted manure, N2O emissions were significantly reduced by 41% at pF 2.0, but the mitigation effect of charred manure was not observed at lower soil water potentials.......New manure management strategies and technologies are currently being developed in order to reduce manure volume and odorous emissions, utilise energy potential and produce improved manure-derived fertilisers. This has accentuated the need to determine their effects on greenhouse gas emissions...

  12. Influence of Pyrolysis Temperature on Rice Husk Char Characteristics and Its Tar Adsorption Capability

    Directory of Open Access Journals (Sweden)

    Anchan Paethanom

    2012-11-01

    Full Text Available A biomass waste, rice husk, was inspected by thermoanalytical investigation to evaluate its capability as an adsorbent medium for tar removal. The pyrolysis process has been applied to the rice husk material at different temperatures 600, 800 and 1000 °C with 20 °C/min heating rate, to investigate two topics: (1 influence of temperature on characterization of rice husk char and; (2 adsorption capability of rice husk char for tar removal. The results showed that subsequent to high temperature pyrolysis, rice husk char became a highly porous material, which was suitable as tar removal adsorbent with the ability to remove tar effectively. In addition, char characteristics and tar removal ability were significantly influenced by the pyrolysis temperature.

  13. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuchynka, D. [Mirage Systems, Sunnyvale, CA (United States)

    1995-10-01

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. This report describes the ChemChar thermolytic detoxification process. The process is a thermal, chemically reductive technology that converts the organic portion of mixed wastes to a synthesis gas, while simultaneously absorbing volatile inorganics on a carbon-based char.

  14. Magnetic separation of carbon-encapsulated Fe nanoparticles from thermally-treated wood char

    Science.gov (United States)

    Sung Phil Mun; Zhiyong Cai; Jilei Zhang

    2013-01-01

    Wood char,a by-product from the fast-pyrolysis process of southern yellow pine wood for bio-oil production, was carbonized with Fenano particles (FeNPs) as a catalyst to prepare carbon-encapsulated Fe nanoparticles. A magnetic separation method was tested to isolate carbon-encapsulated Fe nano particles from the carbonized char. X-ray diffraction pattern clearly shows...

  15. Techno-Economic Assessment of Pyrolysis Char Production and Application – A Review

    OpenAIRE

    Kuppens, Tom; Van Dael, Miet; VANREPPELEN, Kenny; Carleer, Robert; YPERMAN, Jan; SCHREURS, Sonja; VAN PASSEL, Steven

    2014-01-01

    Many organic residue streams such as pig manure are not or inefficiently used, although they can be converted into valuable materials, as well as energy, using pyrolysis. The yield of the pyrolysis products (i.e. oil, gas and char) is dependent on the process conditions and the feedstock used. Char as a soil amendment or activated carbon are interesting options for valorization of biomass residues. Here, a review is presented of the techno-economic potential of both valorization options based...

  16. Influence of post-treatment strategies on the properties of activated chars from broiler manure.

    Science.gov (United States)

    Lima, Isabel M; Boykin, Debbie L; Thomas Klasson, K; Uchimiya, Minori

    2014-01-01

    There are a myriad of carbonaceous precursors that can be used advantageously to produce activated carbons or chars, due to their low cost, availability and intrinsic properties. Because of the nature of the raw material, production of granular activated chars from broiler manure results in a significant ash fraction. This study was conducted to determine the influence of several pre- and post-treatment strategies in various physicochemical and adsorptive properties of the resulting activated chars. Pelletized samples of broiler litter and cake were pyrolyzed at 700 °C for 1h followed by a 45 min steam activation at 800 °C at different water flow rates from 1 to 5 mL min(-1). For each activation strategy, samples were either water-rinsed or acid-washed and rinsed or used as is (no acid wash/rinse). Activated char's physicochemical and adsorptive properties towards copper ions were selectively affected by both pre- and post-treatments. Percent ash reduction after either rinsing or acid washing ranged from 1.1 to 15.1% but washed activated chars were still alkaline with pH ranging from 8.4 to 9.1. Acid washing or water rinsing had no significant effect in the ability of the activated char to adsorb copper ions, however it significantly affected surface area, pH, ash content and carbon content. Instead, manure type (litter versus cake) and the activation water flow rate were determining factors in copper ion adsorption which ranged from 38 mg g(-1) to 104 mg g(-1) of activated char. Moreover, strong positive correlations were found between copper uptake and concentration of certain elements in the activated char such as phosphorous, sulfur, calcium and sodium. Rinsing could suffice as a post treatment strategy for ash reduction since no significant differences in the carbon properties were observed between rinsed and acid wash treatments. Published by Elsevier Ltd.

  17. High quality syngas production from microwave pyrolysis of rice husk with char-supported metallic catalysts.

    Science.gov (United States)

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2015-09-01

    This study aimed to obtain the maximum possible gas yield and the high quality syngas production from microwave pyrolysis of rice husk with rice husk char and rice husk char-supported metallic (Ni, Fe and Cu) catalysts. The rice husk char-supported metallic catalysts had developed pore structure and catalytic activity for gas productions and tar conversion. The temperature-rising characteristic, product yields, properties of gas products and tar conversion mechanisms were investigated. It was found that three rice husk char-supported metallic catalysts improved the microwave absorption capability and increased heating rate and final temperature. Rice husk char-supported Ni catalyst presented most effective effects on gas production, e.g. the gas yield is 53.9%, and the volume concentration of desired syngas is 69.96%. Rice husk char-supported Ni and Fe catalysts played pivotal roles in tar conversion that less heavy compounds can be detected along with the reduction of organic compound number. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Properties of slurries made of fast pyrolysis oil and char or beech wood

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Dam-Johansen, Kim

    2014-01-01

    The properties of slurries made of pyrolysis oil mixed with wood, char or ground char were investigated with respect to phase transitions, rheological properties, elemental compositions, and energy density. Also the pumping properties of the slurries were investigated at temperatures of 25, 40...... and 60 C and solid loadings from 0 to 20 wt%. The phase transitions of the wood slurry samples were observed at lower solid loadings compared to the char slurry samples. The apparent viscosity of the slurry samples was found to be considerably impacted by solid loading (0e20 wt%) and temperature (25e60 C......), especially in the phase transition region. The slurry viscosities with 20 wt% char loading, 20 wt% ground char loading and 15 wt% wood loading (at a shear rate of 100 s1) are 0.7, 1.0 and 1.7 Pa.s, respectively at 60 C and these values increases 1.2e1.4 times at 40 C and 3e4 times at 25 C. The wood, char...

  19. The potential applications of using compost chars for removing the hydrophobic herbicide atrazine from solution

    Science.gov (United States)

    Tsui, L.; Roy, W.R.

    2008-01-01

    One commercial compost sample was pyrolyzed to produce chars as a sorbent for removing the herbicide atrazine from solution. The sorption behavior of compost-based char was compared with that of an activated carbon derived from corn stillage. When compost was pyrolyzed, the char yield was greater than 45% when heated under air, and 52% when heated under N2. In contrast, when the corn stillage was pyrolyzed under N2, the yield was only 22%. The N2-BET surface area of corn stillage activated carbon was 439 m2/g, which was much greater than the maximum compost char surface area of 72 m2/g. However, the sorption affinity of the compost char for dissolved atrazine was comparable to that of the corn stillage activated carbon. This similarity could have resulted from the initial organic waste being subjected to a relatively long period of thermal processes during composting, and thus, the compost was more thermally stable when compared with the raw materials. In addition, microorganisms transformed the organic wastes into amorphous humic substances, and thus, it was likely that the microporisity was enhanced. Although this micropore structure could not be detected by the N2-BET method, it was apparent in the atrazine sorption experiment. Overall, the experimental results suggested that the compost sample in current study was a relatively stable material thermally for producing char, and that it has the potential as a feed stock for making high-quality activated carbon. ?? 2007 Elsevier Ltd. All rights reserved.

  20. Effect of cation exchange on the subsequent reactivity of lignite chars to steam. [108 references

    Energy Technology Data Exchange (ETDEWEB)

    Hippo, E. J.; Walker, Jr., P. L.

    1977-03-01

    The purpose of this investigation is to determine the role which cations in coal play in the subsequent reactivity of chars. It is hoped that this investigation will aid in an understanding of the catalytic nature of inorganic constituents in coal during its gasification. It was found that increased heat treatment temperature decreased reactivity. The decrease in reactivity was shown to be due, at least in part, to the changes in the nature of the cation with increased heat treatment temperature. Reactivity was found to be a linear function of the amount of Ca(++) exchange on the demineralized coal. The constant utilization factor over the wide range of loadings employed indicated that below 800/sup 0/C the calcium did not markedly sinter. Potassium, sodium, and calcium-containing chars were found to be much more reactive than the iron and magnesium-containing chars. However, the iron and magnesium containing chars were more reactive than chars produced from the demineralized coal. The iron char was highly active at first but the iron phase was quickly oxidized to a comparatively unreactive ..gamma..Fe/sub 2/O/sub 3/-Fe/sub 3/O/sub 4/ phase. The state of magnesium was found to be MgO. Sodium and calcium were equally active as catalysts but not as active as potassium.

  1. Co-gasification of coal and biomass: Synergy, characterization and reactivity of the residual char.

    Science.gov (United States)

    Hu, Junhao; Shao, Jingai; Yang, Haiping; Lin, Guiying; Chen, Yingquan; Wang, Xianhua; Zhang, Wennan; Chen, Hanping

    2017-11-01

    The synergy effect between coal and biomass in their co-gasification was studied in a vertical fixed bed reactor, and the physic-chemical structural characteristics and gasification reactivity of the residual char obtained from co-gasification were also investigated. The results shows that, conversion of the residual char and tar into gas is enhanced due to the synergy effect between coal and biomass. The physical structure of residual char shows more pore on coal char when more biomass is added in the co-gasification. The migration of inorganic elements between coal and biomass was found, the formation and competitive role of K 2 SiO 3 , KAlSiO 4 , and Ca 3 Al 2 (SiO 4 ) 3 is a mechanism behind the synergy. The graphization degree is enhanced but size of graphite crystallite in the residual char decreases with biomass blending ratio increasing. TGA results strongly suggest the big difference in the reactivity of chars derived from coal and biomass in spite of influence from co-gasification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Microwave-enhanced CO2 gasification of oil palm shell char.

    Science.gov (United States)

    Lahijani, Pooya; Zainal, Zainal Alimuddin; Mohamed, Abdul Rahman; Mohammadi, Maedeh

    2014-04-01

    CO2 gasification of oil palm shell (OPS) char to produce CO through the Boudouard reaction (C + CO2 ↔ 2CO) was investigated under microwave irradiation. A microwave heating system was developed to carry out the CO2 gasification in a packed bed of OPS char. The influence of char particle size, temperature and gas flow rate on CO2 conversion and CO evolution was considered. It was attempted to improve the reactivity of OPS char in gasification reaction through incorporation of Fe catalyst into the char skeleton. Very promising results were achieved in our experiments, where a CO2 conversion of 99% could be maintained during 60 min microwave-induced gasification of iron-catalyzed char. When similar gasification experiments were performed in conventional electric furnace, the superior performance of microwave over thermal driven reaction was elucidated. The activation energies of 36.0, 74.2 and 247.2 kJ/mol were obtained for catalytic and non-catalytic microwave and thermal heating, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Improvement of biomass char-CO{sub 2} gasification reactivity using microwave irradiation and natural catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lahijani, Pooya, E-mail: pooya.lahijani@gmail.com [Biomass and Bioenergy Laboratory, School of Mechanical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Mohammadi, Maedeh, E-mail: m.mohammadi@nit.ac.ir [Faculty of Chemical Engineering, Babol Noushirvani University of Technology, 47148 Babol (Iran, Islamic Republic of); Zainal, Zainal Alimuddin, E-mail: mezainal@eng.usm.my [Biomass and Bioenergy Laboratory, School of Mechanical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Mohamed, Abdul Rahman, E-mail: chrahman@usm.my [Low Carbon Economy (LCE) Research Group, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-20

    Highlights: • We study microwave-induced gasification of EFB ash-loaded biomass char with CO{sub 2}. • Synergistic effect of microwave and catalyst resulted in CO{sub 2} conversion of 93%. • Gasification of pristine char using conventional heating gives CO{sub 2} conversion of 58%. • E{sub a} of 74 and 247 kJ/mol were obtained for microwave and conventional CO{sub 2} gasification. - Abstract: In char-CO{sub 2} gasification, the highly endothermic nature of the Boudouard reaction (CO{sub 2} (g) + C (s) ↔ 2CO (g)) dictates use of very high temperatures to shift the equilibrium towards CO production. In this study, such high temperature (750–900 °C) was provided by microwave irradiation. A microwave heating system was developed to perform the gasification tests by passing CO{sub 2} through a packed bed of oil palm shell (OPS) char. In order to speed up the microwave-induced CO{sub 2} gasification, ash of palm empty fruit bunch (EFB) was used as natural catalyst (rich in potassium) and incorporated into the skeleton of the OPS char. The synergistic effect of microwave and catalyst concluded to very encouraging results, where a CO{sub 2} conversion of 93% was achieved at 900 °C, within 60 min microwave gasification. In comparison, CO{sub 2} conversion in thermal gasification (conventional heating) of pristine OPS char was only 58% under the same operating condition.

  4. Effect of filling surface-treated pyrolytic char on resistivity of rubber films

    Directory of Open Access Journals (Sweden)

    Pattraporn Yamkaya

    2015-03-01

    Full Text Available In this research, natural rubber (NR films filled with pyrolytic tire char, carbon black N234 and N330 were compared for their electrical resistivity. The filler loading was varied to be 5, 10, 15, 20 and 25% of dry rubber content. The effect of surfactant which is 2 %w/v sodium dodecyl sulfate (SDS was also investigated. In the experiments, it was necessary to disperse the pyrolytic char in ethyl alcohol while disperse carbon black (CB in ammonium hydroxide solution prior to mixing with the rubber latex and the filled NR film was prepared by casting the mixture on a plate. It was found that increasing the amount of pyrolytic char in the NR film could lower its resistivity. The surfactant, SDS, could help better dispersion of both CB and pyrolytic char, thereby decreasing the resistivity. In a separate experiment where hexane vapor was absorbed in NR film without surfactant, in the first 30 seconds, the rate of increasing resistivity of the CB-filled film was not seen as clearly as that of pyrolytic-char-filled film. For the films with surfactant, the slow increase in resistivity of the NR films filled with N330 and pyrolytic char during adsorbing hexane vapor was observed.

  5. Characterization of chars produced in the co-pyrolysis of different wastes: decontamination study.

    Science.gov (United States)

    Bernardo, M; Gonçalves, M; Lapa, N; Barbosa, R; Mendes, B; Pinto, F

    2012-03-15

    The present work is devoted to the study of the decontamination of chars obtained in the co-pyrolysis of plastics, biomass and tyre wastes. The chars were extracted with several organic solvents of different polarities either individually or in sequence. The ability of each selected extractant to remove toxic pollutants was evaluated by comparing the extraction yields and by characterizing the crude extracts with a combination of chemical analysis and toxicity bioassays. Also, the mineral composition of the treated and non-treated chars was assessed. The results obtained in this study indicate that hexane is the more efficient extraction solvent to be used in the organic decontamination of chars obtained in the co-pyrolysis of plastics, tyres and biomass. A sequential extraction with solvents of increasing polarity can provide a better decontamination of the raw pyrolysis char than any individual extraction. The compounds removed from the char during the decontamination process are mainly aliphatic hydrocarbons and aromatic hydrocarbons, therefore a material that may be upgraded to be used as a fuel and/or as raw material for the organic chemical industry. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Standard Test Method for Obtaining Char Density Profile of Ablative Materials by Machining and Weighing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1996-01-01

    1.1 This test method covers the determination of the char density profile of a charred ablator that can be used with the following limitations: 1.1.1 The local surface imperfections must be removed, and the char must be able to be machined off in a plane parallel to the char-virgin material interface before the density profiles can be determined. 1.1.2 The char must be strong enough to withstand the machining and handling techniques employed. 1.1.3 The material should have orderly density variations. The total thickness of the char and degradation zone must be larger than the machining thicknesses required. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.2.1 Exception—Certain inch-pound equivalent units are included in parentheses for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establis...

  7. Enhancement of Handwritings on Selected Charred Documents using Video Spectral Comparator (VSC

    Directory of Open Access Journals (Sweden)

    T. Nataraja Moorthy

    2016-12-01

    Full Text Available Questioned documents are documents whose authenticity is disputed. Documents are destroyed by fires and other means to conceal criminal activities. Charred or burnt documents are a type of questioned document that are likely to contain vital information. These documents are mainly linked to ransoms, forgery, fraud, suicide and other white collar offences. This study aimed to evaluate the ability of a Video Spectral Comparator (VSC-6000 for the enhancement of writings on charred documents and to determine the effectiveness of flood light and white spot beam in VSC on charred documents. A passage was written by different types of writing instruments on different types of writing paper available in Malaysia. Then the handwritten documents were burned until the writings became invisible. The charred documents were viewed under flood light and the white beam by adjusting the wavelengths. Results showed that the writings on the charred document exhibited appreciable enhancement suitable for forensic investigation. The writings were comparatively more visible under the white spot beam than the flood light beam. These findings were recorded through photography. The present study provides a promising method and an effective alternative way to enhance writings on charred documents.

  8. Investigation of wetting behavior of coal-chars with liquid iron by sessile drop method.

    Directory of Open Access Journals (Sweden)

    Veena Sahajwalla

    2008-06-01

    Full Text Available Using the sessile drop approach, the wettability of four non-graphitic coal-chars with electrolytic iron and Fe-2 % C-0.01 % S alloy has been determined at 1550°C, in a horizontal tube resistance furnace with an argon atmosphere. The ash concentration in chars ranged between 9.04 to 12.61 wt %, with alumina and silica as predominant ash components. The contact angles of these chars with liquid Fe-2 % C-0.01 % S alloy showed lesser variations with time as compared to corresponding angles with electrolytic iron. While the initial contact angles ranged between 106° and 137°, the contact angles for all coal-chars were quite similar after 60 minutes of contact (105 - 110°. While no well defined correlations could be observed between the initial char structure (Lc values and ash concentration / composition and contact angles in the initial stages of contact, the contact angles over extended periods were significantly affected by the presence of reaction products and impurity deposits in the interfacial region. With coal-chars generally showing a non-wetting behavior with liquid iron, these results are discussed in terms of the transfer of carbon and sulphur by mass transport across the interface, the formation of an enriched interfacial layer containing calcium, sulphur and alumina, reduction of reducible oxides such as silica and iron oxides, and possible transfer of these elements into the liquid iron.

  9. Co-gasification of tire and biomass for enhancement of tire-char reactivity in CO2 gasification process.

    Science.gov (United States)

    Lahijani, Pooya; Zainal, Zainal Alimuddin; Mohamed, Abdul Rahman; Mohammadi, Maedeh

    2013-06-01

    In this investigation, palm empty fruit bunch (EFB) and almond shell (AS) were implemented as two natural catalysts rich in alkali metals, especially potassium, to enhance the reactivity of tire-char through co-gasification process. Co-gasification experiments were conducted at several blending ratios using isothermal Thermogravimetric analysis (TGA) under CO2. The pronounced effect of inherent alkali content of biomass-chars on promoting the reactivity of tire-char was proven when acid-treated biomass-chars did not exert any catalytic effect on improving the reactivity of tire-char in co-gasification experiments. In kinetic studies of the co-gasified samples in chemically-controlled regime, modified random pore model (M-RPM) was adopted to describe the reactive behavior of the tire-char/biomass-char blends. By virtue of the catalytic effect of biomass, the activation energy for tire-char gasification was lowered from 250 kJ/mol in pure form 203 to 187 kJ/mol for AS-char and EFB-char co-gasified samples, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Measurements of Gasification Characteristics of Coal and Char in CO2-Rich Gas Flow by TG-DTA

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    2013-01-01

    Full Text Available Pyrolysis, combustion, and gasification properties of pulverized coal and char in CO2-rich gas flow were investigated by using gravimetric-differential thermal analysis (TG-DTA with changing O2%, heating temperature gradient, and flow rate of CO2-rich gases provided. Together with TG-DTA, flue gas generated from the heated coal, such as CO, CO2, and hydrocarbons (HCs, was analyzed simultaneously on the heating process. The optimum O2% in CO2-rich gas for combustion and gasification of coal or char was discussed by analyzing flue gas with changing O2 from 0 to 5%. The experimental results indicate that O2% has an especially large effect on carbon oxidation at temperature less than 1100°C, and lower O2 concentration promotes gasification reaction by producing CO gas over 1100°C in temperature. The TG-DTA results with gas analyses have presented basic reference data that show the effects of O2 concentration and heating rate on coal physical and chemical behaviors for the expected technologies on coal gasification in CO2-rich gas and oxygen combustion and underground coal gasification.

  11. Coke, char and organic waste behaviour in the blast furnace with high injection rate

    Directory of Open Access Journals (Sweden)

    Gudenau, H. W.

    2003-10-01

    Full Text Available Blast furnace operation with low coke rate, high amount of auxiliary hydrocarbons and use of nut coke causes a change in coke quality requirements. In particular, not burned in the raceway residues of injected substances (char and ash can influence the coke behaviour. Therefore combustion efficiency of various organic wastes with and without pulverized coal injection (PCI and coal char has been investigated under the raceway simulation conditions. Mixing of various substances improves their combustion efficiency. Study on coke gasification by carbon dioxide in the presence of char showed that with the increase of char concentration, coke strength reduction becomes smaller. The reactivity of char with CO2 is higher than that of coke. Therefore char is consumed preferentially. In presence of injected char, total pore volume in coke and its wear resistance were increased. Coke reactivity and microstructure in the presence of various kinds of ash has been studied. Many ash spheres were observed on the surface of coke matrix and its size was dependent on ash properties.

    La operación del horno alto con una tasa baja de coque, una cantidad elevada de hidrocarburos auxiliares y el empleo de coque calibrado, origina un cambio en las necesidades de calidad del coque. En particular, pueden influir en el comportamiento del coque los residuos inquemados en el raceway (cavidad enfrente a las toberas del horno de las sustancias que se inyectan (char y cenizas. El char es el residuo de carbón que se origina después que el carbón libera sus sustancias volátiles. Por tanto, se ha investigado la eficiencia de la combustión de varios residuos orgánicos con y sin inyección de carbón pulverizado (ICP y char, bajo las condiciones de simulación del raceway. La mezcla de varias sustancias mejora la eficiencia a la combustión. El estudio de la gasificación del coque por el dióxido de carbono en la

  12. Environmental Impacts of the Production and Application of Biochar - EuroChar Project

    Science.gov (United States)

    Rack, Mireille; Woods, Jeremy

    2014-05-01

    One of the potential benefits of biochar is carbon sequestration. To determine the overall net sequestration potential it is important to analyse the full supply chain, assessing both the direct and indirect emissions associated with the production and application of biochar. However, it is essential to also incorporate additional environmental impact categories to ensure the assessment of a more complete environmental impact profile. This paper uses a full life-cycle assessment (LCA) methodology to evaluate the results from the EuroChar, 'biochar for carbon sequestration and large-scale removal of GHG from the atmosphere', project. This EU Seventh Framework Programme project aims to investigate and reduce uncertainties around the impacts of, and opportunities for, biochar, and in particular explore possible pathways for its introduction into modern agricultural systems in Europe. The LCA methodology, according to the ISO standards, is applied to the project-specific supply chains to analyse the environmental impacts of biochar production and application. Two conversion technologies for the production of biochar are assessed, gasification and hydrothermal carbonization (HTC), in order to provide conversion efficiencies and emission factors for the biochar production component of the supply chain. The selected feedstocks include those derived from waste residues and dedicated crops. For the end use stage, various forms and methods for biochar application are considered. In addition to the Global Warming Potential category, other environmental impact categories are also included in the analysis. The resulting 'feedstock * conversion technology' matrix provides nine pathways for the production and application of biochar, which are applied as a representative basis for the scenario modelling. These scenarios have been developed in order to assess the feedstock and land availability in Europe for the production and application of biochar and to give an order of

  13. Properties of chars from the gasification and pyrolysis of rice waste streams towards their valorisation as adsorbent materials.

    Science.gov (United States)

    Dias, D; Lapa, N; Bernardo, M; Godinho, D; Fonseca, I; Miranda, M; Pinto, F; Lemos, F

    2017-07-01

    Rice straw (RS), rice husk (RH) and polyethylene (PE) were blended and submitted to gasification and pyrolysis processes. The chars obtained were submitted to textural, chemical, and ecotoxic characterisations, towards their possible valorisation. Gasification chars were mainly composed of ashes (73.4-89.8wt%), while pyrolysis chars were mainly composed of carbon (53.0-57.6wt%). Silicon (Si) was the major mineral element in all chars followed by alkaline and alkaline-earth metal species (AAEMs). In the pyrolysis chars, titanium (Ti) was also a major element, as the feedstock blends contained high fractions of PE which was the main source of Ti. Gasification chars showed higher surface areas (26.9-62.9m 2 g -1 ) and some microporosity, attributed to porous silica. On the contrary, pyrolysis chars did not present a porous matrix, mainly due to their high volatile matter content. The gasification bed char produced with 100% RH, at 850°C, with O 2 as gasification agent, was selected for further characterization. This char presented the higher potential to be valorised as adsorbent material (higher surface area, higher content of metal cations with exchangeable capacity, and lowest concentrations of toxic heavy metals). The char was submitted to an aqueous leaching test to assess the mobility of chemical species and the ecotoxic level for V. fischeri. It was observed that metallic elements were significantly retained in the char, which was attributed mainly to its alkaline character. This alkaline condition promoted some ecotoxicity level on the char eluate that was eliminated after the pH correction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Gasification of the char derived from distillation of granulated scrap tyres.

    Science.gov (United States)

    López, Félix A; Centeno, Teresa A; Alguacil, Francisco José; Lobato, Belén; López-Delgado, Aurora; Fermoso, Javier

    2012-04-01

    This work reports the effect of pressure on the steam/oxygen gasification at 1000°C of the char derived from low temperature-pressure distillation of granulated scrap tyres (GST). The study was based on the analysis of gas production, carbon conversion, cold gas efficiency and the high heating value (HHV) of the product. For comparison, similar analyses were carried out for the gasification of coals with different rank. In spite of the relatively high ash (≈12 wt.%) and sulphur (≈3 wt.%) contents, the char produced in GST distillation can be regarded as a reasonable solid fuel with a calorific value of 34MJkg(-1). The combustion properties of the char (E(A)≈50 kJ mol(-1)), its temperature of self-heating (≈264°C), ignition temperature (≈459°C) and burn-out temperature (≈676°C) were found to be similar to those of a semi-anthracite. It is observed that the yield, H(2) and CO contents and HHV of the syngas produced from char gasification increase with pressure. At 0.1 MPa, 4.6 Nm(3)kg(char)(-1) of syngas was produced, containing 28%v/v of H(2) and CO and with a HHV around 3.7 MJ Nm(-3). At 1.5 MPa, the syngas yield achieved 4.9N m(3)kg(char)(-1) with 30%v/v of H(2)-CO and HHV of 4.1 MJ Nm(-3). Carbon conversion significantly increased from 87% at 0.1 MPa to 98% at 1.5 MPa. It is shown that the char derived from distillation of granulated scrap tyres can be further gasified to render a gas of considerable heating value, especially when gasification proceeds at high pressure. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Structural ordering of coal char during heat treatment and its impact on reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Feng, B.; Bhatia, S.K.; Barry, J.C.

    2002-07-01

    The effect of heat treatment on the structure of an Australian semi-anthracite char was studied between 850-1150{sup o}C using XRD, HRTEM, and electrical resistivity techniques. It was found that the carbon crystallite size in the char does not change during heat treatment, for both the raw coal and its ash-free derivative obtained by acid treatment. However, the fraction of the organized carbon in the raw coal chars, determined by XRD, increased with increase of heat treatment time and temperature, while that for the ash-free coal chars remained unchanged. This suggests the occurrence of catalytic ordering during heat treatment. Electrical resistivity of the raw coal chars decreased with heat treatment, while that of the ash-free coal chars did not vary. High resolution transmission electron micrographs depicted well-organized carbon layers surrounding iron particles. The fraction of organized carbon attains an apparent equilibrium value that increases with increase in temperature. Good temperature-independent correlation was found between the electrical resistivity and the organized carbon fraction, indicating that electrical resistivity is structure sensitive. These results suggest that the thermal deactivation is the result of a crystallite-perfecting process, which is effectively catalyzed by the inorganic matter in the coal char. It is concluded that the process is diffusion controlled, most likely involving transport of iron in the inter-crystallite nanospaces in the temperature range studied. The activation energy of this transport process is found to be low, which is corroborated by model-free correlation of the temporal variation of organized carbon fraction as well as electrical resistivity data using the superposition method, and is suggestive of surface transport of iron.

  16. Ash of palm empty fruit bunch as a natural catalyst for promoting the CO₂ gasification reactivity of biomass char.

    Science.gov (United States)

    Lahijani, Pooya; Zainal, Zainal Alimuddin; Mohamed, Abdul Rahman; Mohammadi, Maedeh

    2013-03-01

    Palm empty fruit bunch ash (EFB-ash) was used as a natural catalyst, rich in potassium to enhance the CO2 gasification reactivity of palm shell char (PS-char). Various EFB-ash loadings (ranging from 0 to 12.5wt.%) were implemented to improve the reactivity of PS-char during CO2 gasification studies using thermogravimetric analysis. The achieved results explored that the highest gasification reactivity was devoted to 10% EFB-ash loaded char. The SEM-EDS and XRD analyses further confirmed the successful loading of EFB-ash on PS-char which contributed to promoting the gasification reactivity of char. Random pore model was applied to determine the kinetic parameters in catalytic gasification of char at various temperatures of 800-900°C. The dependence of char reaction rate on gasification temperature resulted in a straight line in Arrhenius-type plot, from which the activation energy of 158.75kJ/mol was obtained for the catalytic char gasification. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Thermal decomposition and gasification of biomass pyrolysis gases using a hot bed of waste derived pyrolysis char.

    Science.gov (United States)

    Al-Rahbi, Amal S; Onwudili, Jude A; Williams, Paul T

    2016-03-01

    Chars produced from the pyrolysis of different waste materials have been investigated in terms of their use as a catalyst for the catalytic cracking of biomass pyrolysis gases during the two-stage pyrolysis-gasification of biomass. The chars were produced from the pyrolysis of waste tyres, refused derived fuel and biomass in the form of date stones. The results showed that the hydrocarbon tar yields decreased significantly with all the char materials used in comparison to the non-char catalytic experiments. For example, at a cracking temperature of 800°C, the total product hydrocarbon tar yield decreased by 70% with tyre char, 50% with RDF char and 9% with biomass date stones char compared to that without char. There was a consequent increase in total gas yield. Analysis of the tar composition showed that the content of phenolic compounds decreased and polycyclic aromatic hydrocarbons increased in the product tar at higher char temperatures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The efficacy of high-throughput sequencing and target enrichment on charred archaeobotanical remains.

    Science.gov (United States)

    Nistelberger, H M; Smith, O; Wales, N; Star, B; Boessenkool, S

    2016-11-24

    The majority of archaeological plant material is preserved in a charred state. Obtaining reliable ancient DNA data from these remains has presented challenges due to high rates of nucleotide damage, short DNA fragment lengths, low endogenous DNA content and the potential for modern contamination. It has been suggested that high-throughput sequencing (HTS) technologies coupled with DNA enrichment techniques may overcome some of these limitations. Here we report the findings of HTS and target enrichment on four important archaeological crops (barley, grape, maize and rice) performed in three different laboratories, presenting the largest HTS assessment of charred archaeobotanical specimens to date. Rigorous analysis of our data - excluding false-positives due to background contamination or incorrect index assignments - indicated a lack of endogenous DNA in nearly all samples, except for one lightly-charred maize cob. Even with target enrichment, this sample failed to yield adequate data required to address fundamental questions in archaeology and biology. We further reanalysed part of an existing dataset on charred plant material, and found all purported endogenous DNA sequences were likely to be spurious. We suggest these technologies are not suitable for use with charred archaeobotanicals and urge great caution when interpreting data obtained by HTS of these remains.

  19. Effects of Hybrid Fibre Reinforcement on Fire Resistance Performance and Char Morphology of Intumescent Coating

    Directory of Open Access Journals (Sweden)

    Amir N.

    2016-01-01

    Full Text Available Recent researches of fire retardant intumescent coatings reinforced by single Rockwool and single glass wool fibre at various weight percentages and lengths showed some improvements to the mechanical properties of the coatings and the char produced. Therefore, in this research the fibres were combined together in intumescent coating formulation at several weight percentages and fibre lengths to study their effects towards fire resistance performance and char morphology. The hybrid fibre reinforced intumescent coatings were subjected to two types of fire tests; Bunsen burner at 1000°C and the electric furnace at 800°C for 1 hour, respectively. Steel temperature of the coated samples during Bunsen burner test was recorded to determine the fire resistance performance. Thermal stability of the intumescent coatings and chars was determined by Thermogravimetric Analysis (TGA. The morphology of the coatings and char was then examined by using Scanning Electron Microscopy (SEM and Energy Dispersive Spectrometry (EDS was conducted to obtain elemental composition of the samples. This research concluded that long-hybrid fibre at 12-mm length and 0.6% fibre-weight produced the top performing hybrid fibre intumescent formulation. The hybrid fibres form survived at elevated temperature, hence helped to provide structure and strengthen the char with the highest fire resistance was recorded at steel temperature of 197°C.

  20. Properties of chars obtained with pyrolysis of Castanea sativa by product

    Directory of Open Access Journals (Sweden)

    Pehlivan Eylem

    2017-01-01

    Full Text Available The application of biomass derived energy is gaining importance due to the decreasing supply of fossil fuels and growing environmental concerns. This study described the possibility of utilizing Castanea sativa’s by-product as biofuels by producing char via pyrolysis. The process was carried out in a fixed-bed reactor at different heating rates of 10°C, 100°C, and 200°C per minute at temperatures ranging from 400°C to 700°C, and a nitrogen flow rate of 100 cm3 per minute. The produced chars were characterized by proximate and elemental analyses, Brunauer-Emmett-Teller surface area, nuclear magnetic resonance, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray fluorescence analyses. The char yield was found to decrease as both pyrolysis temperature and heating rate increases. The carbon content of char ranged from 68 to 87 wt.%, which correspond to approximately 43% of carbon in the biomass. The char obtained at 700°C had high fixed carbon content (79.90% as well as high heating value, and hence, it could be used as a solid fuel or as a precursor in the activated carbon production with its 268 m2 per gram surface area.

  1. Changes of wood anatomical characters of selected species of Araucaria- during artificial charring - implications for palaeontology

    Directory of Open Access Journals (Sweden)

    Isa Carla Osterkamp

    2017-11-01

    Full Text Available ABSTRACT Charcoal is widely accepted as evidence of the occurrence of palaeo-wildfire. Although fossil charcoal remains have been used in many studies, investigation into the anatomical changes occurring during charring are few. The present study analyses changes in selected anatomical characters during artificial charring of modern wood of three species of the genus Araucaria (i.e. Araucaria angustifolia, Araucaria bidwillii and Araucaria columnaris. Wood samples of the studied species was charred under controlled conditions at varying temperatures. Measurements of anatomical features of uncharred wood and artificial charcoal were statistically analysed. The anatomical changes were statistically correlated with charring temperatures and most of the parameters showed marked decreases with increasing charring temperature. Compared to the intrinsic variability in anatomical features, both within and between growth rings of an individual plant, the changes induced by temperature account only for a comparatively small percentage of the observed variability. Regarding Araucaria charcoal, it seems possible that at least general taxonomic and palaeoenvironmental implications can be drawn from such material. However, it is not clear so far whether these results and interpretations based on only three taxa, can be generalized for the entire family and anatomically similar fossil taxa or not.

  2. Temperature influence on the fast pyrolysis of manure samples: char, bio-oil and gases production

    Directory of Open Access Journals (Sweden)

    Fernandez-Lopez Maria

    2017-01-01

    Full Text Available Fast pyrolysis characterization of three dry manure samples was studied using a pyrolyzer. A heating rate of 600°C/s and a holding time of 10 s were selected to reproduce industrial conditions. The effect of the peak pyrolysis temperature (600, 800 and 1000°C on the pyrolysis product yield and composition was evaluated. Char and bio-oil were gravimetrically quantified. Scanning electron microscopy (SEM was used to analyse the char structure. H2, CH4, CO and CO2 were measured by means of gas chromatography (GC. A decrease in the char yield and an increase of the gas yield were observed when temperature increased. From 800°C on, it was observed that the char yield of samples Dig R and SW were constant, which indicated that the primary devolatilization reactions stopped. This fact was also corroborated by GC analysis. The bio-oil yield slightly increased with temperature, showing a maximum of 20.7 and 27.8 wt.% for samples Pre and SW, respectively, whereas sample Dig R showed a maximum yield of 16.5 wt.% at 800°C. CO2 and CO were the main released gases whereas H2 and CH4 production increased with temperature. Finally, an increase of char porosity was observed with temperature.

  3. Biomass gasification chars for mercury capture from a simulated flue gas of coal combustion.

    Science.gov (United States)

    Fuente-Cuesta, A; Diaz-Somoano, M; Lopez-Anton, M A; Cieplik, M; Fierro, J L G; Martínez-Tarazona, M R

    2012-05-15

    The combustion of coal can result in trace elements, such as mercury, being released from power stations with potentially harmful effects for both human health and the environment. Research is ongoing to develop cost-effective and efficient control technologies for mercury removal from coal-fired power plants, the largest source of anthropogenic mercury emissions. A number of activated carbon sorbents have been demonstrated to be effective for mercury retention in coal combustion power plants. However, more economic alternatives need to be developed. Raw biomass gasification chars could serve as low-cost sorbents for capturing mercury since they are sub-products generated during a thermal conversion process. The aim of this study was to evaluate different biomass gasification chars as mercury sorbents in a simulated coal combustion flue gas. The results were compared with those obtained using a commercial activated carbon. Chars from a mixture of paper and plastic waste showed the highest retention capacity. It was found that not only a high carbon content and a well developed microporosity but also a high chlorine content and a high aluminium content improved the mercury retention capacity of biomass gasification chars. No relationship could be inferred between the surface oxygen functional groups and mercury retention in the char samples evaluated. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Effect of bone char application on Pb bioavailability in a Pb-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shibao [Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Institute of Natural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); Zhu Yongguan [Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)]. E-mail: ygzhu@mail.rcees.ac.cn; Ma Yibing [Institute of Natural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); McKay, G. [Department of Chemical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2006-02-15

    The effects of bone char (BC) application on the bioavailability of Pb in a polluted soil from Hunan Province, China were examined. The Pb-contaminated soil was treated with two types of bone char, one from the UK and the other from China. The bioavailability of Pb was determined in terms of the uptake by Chinese cabbage (Brassica chinensis L.), sequential extraction and X-ray diffraction analysis. The results indicate that the Pb concentrations in both shoots and roots decreased with increasing quantities of added bone char, and the application of BC from the UK at the rate of 1.6% (w:w) had the largest effect. Lead Pb concentrations in the shoots and roots decreased by 56.0% and 75.9%, respectively, whereas the application of BC from Zhejiang Province, China at the rate of 1.6% (w:w) reduced Pb concentrations in the shoots and roots to 2.04 mg kg{sup -1} and 8.42 mg kg{sup -1}, respectively, only 45.8% and 30.2% compared to the control treatment. Sequential extraction results indicate that the addition of bone char, as a metal-immobilizing agent, substantially transforms soil Pb from non-residual fractions to the residual fraction. The transformation was further confirmed using X-ray diffraction studies. - Bone char amendments show potential for remediation of Pb-contaminated soils.

  5. NO formation during oxy-fuel combustion of coal and biomass chars

    DEFF Research Database (Denmark)

    Zhao, Ke; Jensen, Anker Degn; Glarborg, Peter

    2014-01-01

    The yields of NO from combustion of bituminous coal, lignite, and biomass chars were investigated in O2/N2 and O2/CO 2 atmospheres. The experiments were performed in a laboratory-scale fixed-bed reactor in the temperature range of 850-1150 °C. To minimize thermal deactivation during char preparat......The yields of NO from combustion of bituminous coal, lignite, and biomass chars were investigated in O2/N2 and O2/CO 2 atmospheres. The experiments were performed in a laboratory-scale fixed-bed reactor in the temperature range of 850-1150 °C. To minimize thermal deactivation during char...... preparation, the chars were generated by in situ pyrolysis at the reaction temperature. The NO yield clearly decreased and the CO yield increased when the atmosphere was altered from O2/N 2 to O2/CO2 at 850 °C, but only small differences in NO and CO yields were observed between the two atmospheres at 1050...

  6. Bitumen on Water: Charred Hay as a PFD (Petroleum Flotation Device

    Directory of Open Access Journals (Sweden)

    Nusrat Jahan

    2015-10-01

    Full Text Available Global demand for petroleum keeps increasing while traditional supplies decline. One alternative to the use of conventional crude oils is the utilization of Canadian bitumen. Raw bitumen is a dense, viscous, semi-liquid that is diluted with lighter crude oil to permit its transport through pipelines to terminals where it can then be shipped to global markets. When spilled, it naturally weathers to its original form and becomes dense enough to sink in aquatic systems. This severely limits oil spill recovery and remediation options. Here we report on the application of charred hay as a method for modifying the surface behavior of bitumen in aquatic environments. Waste or surplus hay is abundant in North America. Its surface can easily be modified through charring and/or chemical treatment. We have characterized the modified and charred hay using solid-state NMR, contact angle measurements and infrared spectroscopy. Tests of these materials to treat spilled bitumen in model aquatic systems have been undertaken. Our results indicate that bitumen spills on water will retain their buoyancy for longer periods after treatment with charred hay, or charred hay coated with calcium oxide, improving recovery options.

  7. Tar reduction in pyrolysis vapours from biomass over a hot char bed.

    Science.gov (United States)

    Gilbert, P; Ryu, C; Sharifi, V; Swithenbank, J

    2009-12-01

    The behaviour of pyrolysis vapours over char was investigated in order to maximise tar conversion for the development of a new fixed bed gasifier. Wood samples were decomposed at a typical pyrolysis temperature (500 degrees C) and the pyrolysis vapours were then passed directly through a tar cracking zone in a tubular reactor. The product yields and properties of the condensable phases and non-condensable gases were studied for different bed lengths of char (0-450 mm), temperatures (500-800 degrees C), particle sizes (10 and 15 mm) and nitrogen purge rates (1.84-14.70 mm/s). The carbon in the condensable phases showed about 66% reduction by a 300 mm long char section at 800 degrees C, compared to that for pyrolysis at 500 degrees C. The amount of heavy condensable phase decreased with increasing temperature from about 18.4 wt% of the biomass input at 500 degrees C to 8.0 wt% at 800 degrees C, forming CO, H(2) and other light molecules. The main mode of tar conversion was found to be in the vapour phase when compared to the results without the presence of char. The composition of the heavy condensable phase was simplified into much fewer secondary and tertiary tar components at 800 degrees C. Additional measures were required to maximise the heterogeneous effect of char for tar reduction.

  8. Parallel and series-reaction mechanisms of wood and char combustion

    Directory of Open Access Journals (Sweden)

    Branca Carmen

    2004-01-01

    Full Text Available Thermo gravimetric curves in air of beech wood and char, obtained from conventional pyrolysis of beech wood at a laboratory scale, have been re-examined using different kinetic models. Multi-step reaction mechanisms consisting of either four (wood or two (char reactions are needed for accurate predictions of weight loss curves. In the case of wood, three reactions are linear in the reactant mass fraction whereas the fourth step presents a power-law dependence. A linear reaction for devolatilization and a non-linear reaction for combustion are used for the weight loss curves of char. It has been found that activation energies and pre-exponential factors are in variant with series or parallel reactions, providing changes in the stoichiometric coefficients. Further more, the activation energies of the two reactions occurring at higher temperatures in the four-step mechanism (wood and those of the two-step mechanism (char are the same. Thus pre-exponential factors and reaction order take into account variations in the char reactivity derived from different pyrolysis conditions.

  9. Temperature influence on the fast pyrolysis of manure samples: char, bio-oil and gases production

    Science.gov (United States)

    Fernandez-Lopez, Maria; Anastasakis, Kostas; De Jong, Wiebren; Valverde, Jose Luis; Sanchez-Silva, Luz

    2017-11-01

    Fast pyrolysis characterization of three dry manure samples was studied using a pyrolyzer. A heating rate of 600°C/s and a holding time of 10 s were selected to reproduce industrial conditions. The effect of the peak pyrolysis temperature (600, 800 and 1000°C) on the pyrolysis product yield and composition was evaluated. Char and bio-oil were gravimetrically quantified. Scanning electron microscopy (SEM) was used to analyse the char structure. H2, CH4, CO and CO2 were measured by means of gas chromatography (GC). A decrease in the char yield and an increase of the gas yield were observed when temperature increased. From 800°C on, it was observed that the char yield of samples Dig R and SW were constant, which indicated that the primary devolatilization reactions stopped. This fact was also corroborated by GC analysis. The bio-oil yield slightly increased with temperature, showing a maximum of 20.7 and 27.8 wt.% for samples Pre and SW, respectively, whereas sample Dig R showed a maximum yield of 16.5 wt.% at 800°C. CO2 and CO were the main released gases whereas H2 and CH4 production increased with temperature. Finally, an increase of char porosity was observed with temperature.

  10. Kinetics and Mechanisms of NO(x) - Char Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Suuberg, E.M.; Lilly, W.D.; Aarna, I.

    1997-09-01

    The emission of nitrogen oxides from combustion of coal remains a problem of considerable interest, whether the concern is with acid rain, stratospheric ozone chemistry, or greenhouse gases. Whereas earlier the concern was focused mainly on NO (as a primary combustion product) and to a lesser extent N0{sub 2} (since it is mainly a secondary product of combustion, e.g. see ref. 1), in recent years the emissions of N{sub 2}0 have also captured considerable attention, particularly in the context of fluidized bed combustion, in which the problem appears to be most acute. The research community has only recently begun to take solid hold on the N{sub 2}0 problem. This is in part because earlier estimates of the importance of N{sub 2}0 in combustion processes were clouded by artifacts in sampling which have now been resolved. This project is concerned with the mechanism of reduction of both NO and N{sub 2}0 by carbons. It was recognized some years ago that NO formed during fluidized bed coal combustion can be heterogeneously reduced in-situ by the carbonaceous solid intermediates of combustion. This has been recently supplemented by the knowledge that heterogeneous reaction with carbon can also play an important role in reducing emissions of N{sub 2}0{sub 2}, but that the NO-carbon reactions might also contribute to formation of N{sub 2}0{sub 2}. The precise role of carbon in N{sub 2}0 reduction and formation has yet to be established, since in one case the authors of a recent study were compelled to comment that the basic knowledge of N{sub 2}0 formation and reduction still has to be improved. The same can be said of the NO-carbon system. Interest in the NO- and N{sub 2}0-char reactions has been significant in connection with both combustor modeling, as well as in design of post-combustion NO{sub x} control strategies.

  11. A solid state NMR investigation of char forming processes in polymer degradation

    CERN Document Server

    Dick, C M

    2002-01-01

    A detailed knowledge of the condensed phase chemistry occurring in polymers exposed to elevated temperatures is crucial to understanding the behaviour of polymers exposed to fire. This is particularly true when trying to reduce polymer flammability by means of promoting char-forming reactions. Until recently, however, structural information on highly crosslinked chars and their precursors has been difficult to obtain, and as a consequence many degradation workers have merely labelled degradation residues as 'intractable'. However, the application of solid state NMR techniques developed in our laboratories for the structural characterisation of coals has provided a considerable insight into the structure and chemistry of polymer chars formed under both oxidative and non-oxidative conditions. A series of polymers including poly(vinyl chloride), poly(vinyl acetate), polyurethanes, polychloropene, cis and trans polyisoprene have been studied. These polymers have been used to describe the application of quantitati...

  12. Coal Char Derived Few-Layer Graphene Anodes for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2014-08-01

    Full Text Available Few-layer graphene films were synthesized through chemical vapor deposition technique using coal char as solid carbon source. Raman spectroscopy, X-ray diffraction, transmission electron microscopy, and selected area electron diffraction were used to characterize the graphene films. The electrochemical performance of the coal char derived few layer graphene anodes for lithium ion batteries was investigated by charge/discharge curves  and  discharge  capacity  at  different  current  densities.  The  graphene  anode maintained the reversible capacity at ~0.025, 0.013, and 0.007 mAh/cm2  at a current density of 10, 30, and 50 µA/cm2, respectively. The coal char derived graphene anodes show potential applications in thin film batteries for nanoelectronics.

  13. Influence of fast pyrolysis conditions on yield and structural transformation of biomass chars

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn

    2015-01-01

    Fast pyrolysis of biomass (wood, straw, rice husk) and its major components (cellulose, hemicellulose, lignin) was conducted in a wire mesh reactor. The aim of this study was to understand the influence of temperature (350-1400 ° C), heating rate (10-3000 ° C/s), particle size (0.05-2 mm) and hol......Fast pyrolysis of biomass (wood, straw, rice husk) and its major components (cellulose, hemicellulose, lignin) was conducted in a wire mesh reactor. The aim of this study was to understand the influence of temperature (350-1400 ° C), heating rate (10-3000 ° C/s), particle size (0.05-2 mm...... that the heat treatment temperature had a larger influence on the char yield than the heating rate. Scanning electron microscopy indicated different types of biomass char plasticization influenced by the applied temperatures, heating rates, particle sizes and holding times, except for the rice husk char...

  14. An analysis of a charring ablator with thermal nonequilibrium, chemical kinetics, and mass transfer

    Science.gov (United States)

    Clark, R. K.

    1973-01-01

    The differential equations governing the transient response of a one-dimensional ablative thermal protection system are presented for thermal nonequilibrium between the pyrolysis gases and the char layer and with finite rate chemical reactions occurring. The system consists of three layers (the char layer, the uncharred layer, and an optical insulation layer) with concentrated heat sinks at the back surface and between the second and third layers. The equations are solved numerically by using a modified implicit finite difference scheme to obtain solutions for the thickness of the charred and uncharred layers, surface recession and pyrolysis rates, solid temperatures, porosity profiles, and profiles of pyrolysis-gas temperature, pressure, composition, and flow rate. Good agreement is obtained between numerical results and exact solutions for a number of simplified cases. The complete numerical analysis is used to obtain solutions for an ablative system subjected to a constant heating environment. Effects of thermal, chemical, and mass transfer processes are shown.

  15. Sulfur retention by ash during coal combustion. Part I. A model of char particle combustion

    Directory of Open Access Journals (Sweden)

    BORISLAV GRUBOR

    2003-02-01

    Full Text Available A model for the combustion of porous char particles as a basis for modeling the process of sulfur retention by ash during coal combustion is developed in this paper. The model belongs to the microscopic intrinsic models and describes the dynamic behavior of a porous char particle during comustion, taking into account temporal and spatial changes of all important physical properties of the char particle and various combustion parameters. The parametric analysis of the enhanced model shows that the model represents a good basis for the development of a model for the process of sulfur retention by ash during coal combustion. The model enables the prediction of the values of all parameters necessary for the introduction of reactions between sulfur compounds and mineral components in ash, primarily calcium oxide.

  16. The influence of wildfire severity on soil char composition and nitrogen dynamics

    Science.gov (United States)

    Rhoades, Charles; Fegel, Timothy; Chow, Alex; Tsai, Kuo-Pei; Norman, John, III; Kelly, Eugene

    2017-04-01

    Forest fires cause lasting ecological changes and alter the biogeochemical processes that control stream water quality. Decreased plant nutrient uptake is the mechanism often held responsible for lasting post-fire shifts in nutrient supply and demand, though other upland and in-stream factors also likely contribute to elevated stream nutrient losses. Soil heating, for example, creates pyrogenic carbon (C) and char layers that influence C and nitrogen (N) cycling. Char layer composition and persistence vary across burned landscapes and are influenced first by fire behavior through the temperature and duration of combustion and then by post-fire erosion. To evaluate the link between soil char and stream C and N export we studied areas burned by the 2002 Hayman Fire, the largest wildfire in Colorado, USA history. We compared soil C and N pools and processes across ecotones that included 1) unburned forests, 2) areas with moderate and 3) high wildfire severity. We analyzed 1-2 cm thick charred organic layers that remain visible 15 years after the fire, underlying mineral soils, and soluble leachate from both layers. Unburned soils released more dissolved organic C and N (DOC and DON) from organic and mineral soil layers than burned soils. The composition of DOC leachate characterized by UV-fluorescence, emission-excitation matrices (EEMs) and Fluorescence Regional Integration (FRI) found similarity between burned and unburned soils, underscoring a common organic matter source. Humic and fulvic acid-like fractions, contained in regions V and III of the FRI model, comprised the majority of the fluorescing DOM in both unburned and char layers. Similarity between two EEMs indices (Fluorescence and Freshness), further denote that unburned soils and char layers originate from the same source and are consistent with visual evidence char layers contain significant amounts of unaltered OM. However, the EEMs humification index (HIX) and compositional analysis with pyrolysis GCMS

  17. Structural evolution of biomass char and its effect on the gasification rate

    DEFF Research Database (Denmark)

    Fatehi, Hesameddin; Bai, Xue Song

    2017-01-01

    during the entire conversion process. This model is used to analyze the steam gasification process of biomass char of centimeter sizes. The results from the present multi-pore model are in better agreement with experimental data than those from a corresponding single pore model. Since the multi......-pore model accommodates the detailed intra-particle transport, it is a useful basis toward developing a more predictive model for biomass char gasification....... with different radii. The model is valid for biomass chars produced under relatively low heating rates, when the original beehive structure of the biomass is not destroyed during the pyrolysis stage. The contribution of different pores with different radius is taken into account using an effectiveness factor...

  18. Determination of the calcium species in coal chars by Ca K-edge XANES analysis

    Science.gov (United States)

    Liu, Li-Juan; Liu, Hui-Jun; Cui, Ming-Qi; Hu, Yong-Feng; Zheng, Lei; Zhao, Yi-Dong; Ma, Chen-Yan; Xi, Shi-Bo; Yang, Dong-Liang; Guo, Zhi-Ying; Wang, Jie

    2013-02-01

    Ca-based additives have been widely used as a sulfur adsorbent during coal pyrolysis and gasification. The Ca speciation and evolution during the pyrolysis of coal with Ca additives have attracted great attention. In this paper, Ca species in the coal chars prepared from the pyrolysis of Ca(OH)2 or CaCO3-added coals are studied by using Ca K-edge X-ray absorption near-edge structural spectroscopy. The results demonstrate that Ca(OH)2, CaSO4, CaS and CaO coexist in the Ca(OH)2-added chars, while Ca(OH)2 and CaSO4 are the main species in the Ca(OH)2-added chars. Besides, a carboxyl-bound Ca is also formed during both the pyrolysis for the Ca(OH)2-added and the CaCO3-added coals. A detailed discussion about the Ca speciation is given.

  19. Fuel gas and char from pyrolysis of waste paper in a microwave plasma reactor

    Energy Technology Data Exchange (ETDEWEB)

    Khongkrapan, Parin; Thanompongchart, Patipat; Tippayawong, Nakorn; Kiatsiriroat, Tanongkiat [Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2013-07-01

    In this study, a microwave plasma reactor was used for pyrolysis of waste papers. The effects of different argon flow rates on char and gas generation were investigated. Changes in carbon and oxygen contents from those in paper to char were significant. Char yield of over 25 % was obtained with the heating value of about 38 MJ/kg. Average gas yield and total content of combustible fraction (CO, CH4 and H2) in the gas product were 2.56 m3/kg and 36 %, respectively. The heating value of gas product and carbon conversion efficiency of the process were maximum at 6.0 MJ/m3 and 73 %, respectively.

  20. Adsorption of Pb(II by Activated Pyrolytic Char from Used Tire

    Directory of Open Access Journals (Sweden)

    Lu Ping

    2016-01-01

    Full Text Available As a renewable resource, the pyrolytic char derived from used tire has promising adsorption capacities owing to its similar structure and properties with active carbon. The purification and activation of the pyrolytic char from used tire, as well as the application of this material in the adsorption of Pb(II in water is conducted. The influences on the adsorption capacity by temperature and pH value are investigated and discussed; the adsorption thermodynamics and kinetics are also studied. The results show that the pyrolytic char from used tire has remarkable adsorption capacity for Pb(II, and the adsorption is an endothermic process complying with the Langmuir isotherm. The adsorption kinetics is a pseudo second-order reaction.

  1. Charring temperatures are driven by the fuel types burned in a peatland wildfire

    Directory of Open Access Journals (Sweden)

    Victoria A. Hudspith

    2014-12-01

    Full Text Available Peatlands represent a globally important carbon store; however, the human exploitation of this ecosystem is increasing both the frequency and severity of fires on drained peatlands. Yet, the interactions between the hydrological conditions (ecotopes, the fuel types being burned, the burn severity, and the charring temperatures (pyrolysis intensity remain poorly understood. Here we present a post-burn assessment of a fire on a lowland raised bog in Co. Offaly, Ireland (All Saints Bog. Three burn severities were identified in the field (light, moderate, and deeply burned, and surface charcoals were taken from 17 sites across all burn severities. Charcoals were classified into two fuel type categories (either ground or aboveground fuel and the reflectance of each charcoal particle was measured under oil using reflectance microscopy. Charcoal reflectance shows a positive relationship with charring temperature and as such can be used as a temperature proxy to reconstruct minimum charring temperatures after a fire event. Resulting median reflectance values for ground fuels are 1.09 ± 0.32%Romedian, corresponding to estimated minimum charring temperatures of 447°C ± 49°C. In contrast, the median charring temperatures of aboveground fuels were found to be considerably higher, 646°C ± 73°C (3.58 ± 0.77%Romedian. A mixed-effects modelling approach was used to demonstrate that the interaction effects of burn severity, as well as ecotope classes, on the charcoal reflectance is small compared to the main effect of fuel type. Our findings reveal that the different fuel types on raised bogs are capable of charring at different temperatures within the same fire, and that the pyrolysis intensity of the fire on All Saints Bog was primarily driven by the fuel types burning, with only a weak association to the burn severity or ecotope classes.

  2. Polyparameter linear free energy relationship for wood char-water sorption coefficients of organic sorbates.

    Science.gov (United States)

    Plata, Desiree L; Hemingway, Jordon D; Gschwend, Philip M

    2015-07-01

    Black carbons, including soots, chars, activated carbons, and engineered nanocarbons, have different surface properties, but the extent to which these affect their sorbent properties is not known. To evaluate this for an environmentally ubiquitous form of black carbon, biomass char, the surface of a well-studied wood char was probed using 14 sorbates exhibiting diverse functional groups, and the data were fit with a polyparameter linear free energy relationship to assess the importance of the various possible sorbate-char surface interactions. Sorption from water to water-wet char evolved with the sorbate's degree of surface saturation and depended on only a few sorbate parameters: log K(d)L/kg) = [(4.03 ± 0.14) + (-0.15 ± 0.04) log a(i)] V + [(-0.28 ± 0.04) log a(i)] S + (-5.20 ± 0.21) B, where a(i) is the aqueous saturation of the sorbate i, V is McGowan's characteristic volume, S reflects polarity, and B represents the electron-donation basicity. As is generally observed for activated carbon, the sorbate's size encouraged sorption from water to the char, whereas its electron donation and proton acceptance discouraged sorption from water. The magnitude and saturation dependence differed significantly from what has been seen for activated carbons, presumably reflecting the unique surface chemistries of these 2 black carbon materials and suggesting that black carbon-specific sorption coefficients will yield more accurate assessments of contaminant mobility and bioavailability, as well as evaluation of a site's response to remediation. © 2015 SETAC.

  3. Optimization of regenerated bone char for fluoride removal in drinking water: a case study in Tanzania.

    Science.gov (United States)

    Kaseva, M E

    2006-03-01

    This paper presents findings of a study on optimization and application of the regenerated bone char media for the defluoridation of drinking water in Tanzania where more than 30% of all water sources have fluoride concentrations above the 1.50 mg/I which is recommended by the World Heath Organization (WHO). In this study, regeneration temperature, regeneration duration, contact time, regenerated bone char dosage and particle size were investigated. Results indicate that the highest fluoride removal and adsorption capacity were 70.64% and 0.75 mg-F/g-bc, respectively, for a sample with bone char material that was regenerated at 500 degrees C. In this study the optimum burning duration was found to be 120 min, which resulted in residual fluoride that varied from a maximum value of 17.43 mg/I for a 2 min contact time to a minimum value of 8.53 mg/I for a contact time of 180 min. This study further indicated that the smallest size of regenerated bone char media (0.5-1.0 mm diameter) had the highest defluoridation capacity, with residual fluoride which varied from 17.82 mg/I at 2 min contact time to 11.26 mg/I at 120 min contact time. In terms of dosage of the regenerated bone char media it was established that the optimum dosage was 25g of bone char media with a grain size of 0.50-1.0 mm. This had a fluoride removal capacity of 0.55 mg-F/g-BC. Column filter experiments indicated that regenerated bone media is capable of removing fluoride from dinking water to meet both WHO and Tanzania recommended values.

  4. Microstructure development of chars derived from high-temperature pyrolysis of barley (Hordeum vulgare L.) hulls

    Energy Technology Data Exchange (ETDEWEB)

    A.A. Boateng; P.H. Cooke; K.B. Hicks [US Department of Agriculture, Wyndmoor, PA (United States). Agriculture Research Service, Eastern Regional Research Center

    2007-03-15

    Fast pyrolysis of biomass is a thermochemical conversion process that provides an economic production of pyrolysis oils/bio-oils. The process also results in a residual solid residue, char, that comprises carbon and mineral ash that can be a potential source of fuel or a valuable co-product. Depending on the exposure time and temperature, pyrolysis can increase the interfacial surface areas of the residual char thereby enhancing its absorptive capacity. Char residues can be used for physical or chemical absorption and as catalyst support or base material for fertilizers. The reactions that occur during char combustion or gasification are heterogeneous hence the reaction rates are microstructure dependent. Ashes from biomass derived chars can be high either in calcium or silica with the latter exceeding 90% levels in certain grain hull residues. Depending on the microstructural transformations which occur during thermal degradation of the biomass, silica-laden ashes can be a potential source of pozzolan for the construction industry. In this study, the microstructure of the chars derived from fast pyrolysis of barley-hull was studied using environmental scanning electron microscopy under low vacuum conditions. The results indicate a gradual increase in convoluted microstructure related to the superficial organization of epidermal cells, including stomata and trichomes that eventually assume the form of various morphotypes of phytoliths. Characterization of the temporal events of high temperature evolution of the hull microstructure provides practical implications of its combustion reactivities and also provides information useful for predicting potential masonry applications for the resulting ash. 18 refs., 8 figs., 3 tabs.

  5. Virtual autopsy with multidetector computed tomography of three cases of charred bodies.

    Science.gov (United States)

    Cittadini, Francesca; Polacco, Matteo; D'Alessio, Pasquale; Tartaglione, Tommaso; De Giorgio, Fabio; Oliva, Antonio; Zobel, Bruno; Pascali, Vincenzo L

    2010-10-01

    Herein, we report a comparison of multidetector computed tomography (MDCT) and autopsy in the evaluation of three cases of charred human bodies. Interestingly, MDCT identified several findings useful for forensic purposes, including traumatic injuries not related to the fire, relevant vital reaction signs and detection of foreign bodies. Our results, in addition to data gathered in previous studies, indicate that MDCT is an excellent tool for imaging in postmortem investigations and that it has great potential for the forensic documentation and examination of charred bodies.

  6. Microwave Assisted Hydrolysis of Holocellulose Catalyzed with Sulfonated Char Derived from Lignin-Rich Residue

    Directory of Open Access Journals (Sweden)

    Kui Wang

    2015-01-01

    Full Text Available A microwave assisted green process has been developed for production of sugars through liquefying holocellulose catalyzed with sulfonated char derived from the lignin-rich residue produced during pretreatment of lignocellulose. Various reaction parameters including the hydrolysis temperature, hydrolysis time, catalyst content, and the ratio of water to feedstock were evaluated. The maximum sugars yield of 82.6% (based on the dry mass of holocellulose was obtained under the optimum reaction conditions. The sulfonated char showed superior catalytic performance to that of dilute sulfuric acid in converting holocellulose into sugars under microwave irradiation.

  7. Acidification with nitric acid improves chemical characteristics and reduces phytotoxicity of alkaline chars.

    Science.gov (United States)

    Fornes, Fernando; Belda, Rosa Maria

    2017-04-15

    Charred organic matter is recently receiving attention for its potential use as soilless growth medium. However, depending on its origin and on the manufacturing technology, it can result toxic for plants. This fact implies that a detoxifying treatment ought to be devised in order to reclaim char in this way. We have studied three materials which combine these factors: two pyrolyzed biochars, one from forest waste (BCH-FW) and another from olive mill waste (BCH-OMW), and one hydrothermally carbonized hydrochar from forest waste (HYD-FW). These materials are suspicious of phytotoxicity due to their high pH, high salinity, or presence of organic toxics. For these new materials, it is mandatory to select fast and reliable bioassays to predict their potential phytotoxicity. In order to achieve this goal water extracts of the three chars were subjected to bioassays of seed germination and bioassays of seedling growth in hydroponic conditions. The biochar from olive mill waste and the hydrochar, but not the biochar from forest waste, showed considerable phytotoxicity as seed germination and plant growth were negatively affected (e.g. BCH-OMW reduced seed germination by 80% and caused early seedling death). In order to adjust pH and electrical conductivity for plant growth, treatments of acidification and salt leaching with optimal diluted HNO 3 solutions (0.3 N, 0.2 N, and 0.75 N for BCH-OMW, BCH-FW, and HYD-FW, respectively) as calculated from titration curves, were conducted. The acid treatment reduced electrical conductivity in BCH-OMW (from 9.2 to 4.5 dS m -1 ), pH (maximum in BCH-FW from 9.6 to 6.2) and water soluble carbonaceous compounds (maximum in HYD-FW from 5969 to 2145 mg kg -1 ) in the three chars, and increased N content (maximum in BCH-OMW from 50 to 6342 mg kg -1 ) in the three chars. Bioassays on acid-treated chars demonstrated the absence of phytotoxicity and even stimulation of seedling growth over the control (increase of 86% and 56% for BCH

  8. Physicochemical properties and gasification reactivity of the ultrafine semi-char derived from a bench-scale fluidized bed gasifier

    Science.gov (United States)

    Zhang, Yukui; Zhang, Haixia; Zhu, Zhiping; Na, Yongjie; Lu, Qinggang

    2017-08-01

    Zhundong coalfield is the largest intact coalfield worldwide and fluidized bed gasification has been considered as a promising way to achieve its clean and efficient utilization. The purpose of this study is to investigate the physicochemical properties and gasification reactivity of the ultrafine semi-char, derived from a bench-scale fluidized bed gasifier, using Zhundong coal as fuel. The results obtained are as follows. In comparison to the raw coal, the carbon and ash content of the semi-char increase after partial gasification, but the ash fusion temperatures of them show no significant difference. Particularly, 76.53% of the sodium in the feed coal has released to the gas phase after fluidized bed gasification. The chemical compositions of the semi-char are closely related to its particle size, attributable to the distinctly different natures of diverse elements. The semi-char exhibits a higher graphitization degree, higher BET surface area, and richer meso- and macropores, which results in superior gasification reactivity than the coal char. The chemical reactivity of the semi-char is significantly improved by an increased gasification temperature, which suggests the necessity of regasification of the semi-char at a higher temperature. Consequently, it will be considered feasible that these carbons in the semi-char from fluidized bed gasifiers are reclaimed and reused for the gasification process.

  9. Intrinsic reactivity of biomass-derived char under steam gasification conditions. Potential of wood ash as catalyst.

    NARCIS (Netherlands)

    Nanou, Pavlina; Gutierrez Murillo, Hector E.; van Swaaij, Willibrordus Petrus Maria; van Rossum, G.; Kersten, Sascha R.A.

    2013-01-01

    The influence of ash on the steam gasification rate of pine wood derived char particles in the temperature range 600–800 °C is investigated. Ash derived from pine wood or specific ash components were added to the pine-wood (before pyrolysis) or to the produced char (after pyrolysis) via physical

  10. Soil submodel, SCEMR1, for the assessment of Canada`s nuclear fuel waste management concept. AECL research No. AECL-9577

    Energy Technology Data Exchange (ETDEWEB)

    Sheppard, M.I.

    1992-12-31

    One of the main objectives of Canada`s Nuclear Fuel Waste Management Program is to assess the movement of radionuclides using modelling techniques in order to evaluate the acceptability of disposal of nuclear fuel wastes underground in stable plutonic rock. This report describes the soil submodel of the BIOTRAC biosphere model developed to support the assessment. The SCEMR1 soil model is a mechanistic, time-dependent transport model, and the report includes full descriptions of its major subroutines for water and nuclide transport, its input parameter values, and its major assumptions. The report also presents the quality assurance procedures used for developing SCEMR1, results of testing the model using experimental data, simplification and development of SCEMR1 for implementation in BIOTRAC, results of calculations of soil nuclide transport processes, the coupling of SCEMR1 with BIOTRAC using the response function, and validation of the SCEMR1 model in the international BIOMOVS study.

  11. A new seasonal-deciduous spring phenology submodel in the Community Land Model 4.5: impacts on carbon and water cycling under future climate scenarios.

    Science.gov (United States)

    Chen, Min; Melaas, Eli K; Gray, Josh M; Friedl, Mark A; Richardson, Andrew D

    2016-11-01

    A spring phenology model that combines photoperiod with accumulated heating and chilling to predict spring leaf-out dates is optimized using PhenoCam observations and coupled into the Community Land Model (CLM) 4.5. In head-to-head comparison (using satellite data from 2003 to 2013 for validation) for model grid cells over the Northern Hemisphere deciduous broadleaf forests (5.5 million km2 ), we found that the revised model substantially outperformed the standard CLM seasonal-deciduous spring phenology submodel at both coarse (0.9 × 1.25°) and fine (1 km) scales. The revised model also does a better job of representing recent (decadal) phenological trends observed globally by MODIS, as well as long-term trends (1950-2014) in the PEP725 European phenology dataset. Moreover, forward model runs suggested a stronger advancement (up to 11 days) of spring leaf-out by the end of the 21st century for the revised model. Trends toward earlier advancement are predicted for deciduous forests across the whole Northern Hemisphere boreal and temperate deciduous forest region for the revised model, whereas the standard model predicts earlier leaf-out in colder regions, but later leaf-out in warmer regions, and no trend globally. The earlier spring leaf-out predicted by the revised model resulted in enhanced gross primary production (up to 0.6 Pg C yr-1 ) and evapotranspiration (up to 24 mm yr-1 ) when results were integrated across the study region. These results suggest that the standard seasonal-deciduous submodel in CLM should be reconsidered, otherwise substantial errors in predictions of key land-atmosphere interactions and feedbacks may result. © 2016 John Wiley & Sons Ltd.

  12. Reactivity of young chars via energetic distribution measurements. Final report, 1 September 1990--31 December 1994

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Zhang, L.; Lu, W.; Lilly, W.D.

    1996-01-01

    We have developed what we believe to be the very first, a priori, correlation/prediction technique for the gasification reactivity of coal char. With this method the gasification reactivity of a coal char as a function of temperature can be correlated using the data from a temperature programmed desorption (TPD) experiment following gasification under conditions where the reactivity is controlled by the thermal desorption of oxygen surface complexes formed during gasification. The current project was directed at extending and developing related techniques for the characterization and prediction/correlation of the reactivity of the ``young`` chars to CO{sub 2} and steam. Of particular interest was mapping of the reactivity behavior of the resultant chars, as revealed by the energetic heterogeneity of the complexes with char preparation conditions.

  13. Study of blood charring precursor states using backscattering at 663 nm from blood and optical window boundary.

    Science.gov (United States)

    Takahashi, Mei; Ito, Arisa; Miyoshi, Shunichiro; Kimura, Takehiro; Takatsuki, Seiji; Fukumoto, Kotaro; Fukuda, Keiichi; Arai, Tsunenori

    2012-08-01

    Contact laser irradiation is generally used in therapeutic laser procedures such as plastic surgery and laser catheter lead removal. However, it may induce blood charring on the surface of the optical window in blood circumstance so that the laser beam might be blocked. Various charring detection methods have been proposed, but they detect charring only after charring has occurred. This study investigates the transient behavior of red blood cells (RBCs) prior to the charring on the surface of an optical window during red laser irradiation in blood circumstance. The backscattering light power was continuously measured to investigate the transient behavior of a 1-mm-thick porcine blood model (hematocrit: 40%) during continuous laser irradiation (center wavelength: 663 nm; irradiance: 81 W/cm(2)). A rabbit blood model was microscopically observed after irradiation. The absorption coefficient (µ(a)) and the reduced scattering coefficient (μ'(s)) were measured using a double integrating sphere setup and the inverse adding-doubling method. The backscattering light power was continuously measured in vivo during contact laser irradiation via a laser catheter in a porcine heart cavity. The results reveal that it may be possible to detect a precursory state of charring from a time course of the backscattering light power. µ(a) increased monotonically by 15% until charring occurred. μ'(s) decreased by 10% followed a broad peak until charring occurred. These changes in the optical property correspond to changes in the morphology of RBCs. Changes in the backscattering light power measured in vivo were similar to those measured ex vivo. The transient optical changes in blood prior to charring may be caused by changes in the morphology of RBCs on the optical window surface. Backscattering light power measurements may be a practical method to detect the precursor state of charring. Copyright © 2012 Wiley Periodicals, Inc.

  14. Combustion kinetics of char obtained by flash pyrolysis of pine wood

    NARCIS (Netherlands)

    Janse, A.M.C.; Janse, Arthur M.C.; de Jonge, Harald G.; Prins, W.; van Swaaij, Willibrordus Petrus Maria

    1998-01-01

    The combustion kinetics of rapidly pyrolyzed wood have been investigated within the temperature range of 573−773 K and the oxygen concentration range of 2.25−36 vol %. These kinetics are, for instance, required for the design of a char combustion section in an integrated flash pyrolysis pilot plant.

  15. Combustion kinetics of char obtained by flash pyrolysis of pine wood

    NARCIS (Netherlands)

    Janse, A.M.C.; Jonge, de H.G.; Prins, W.; Swaaij, van W.P.M.

    1998-01-01

    The combustion kinetics of rapidly pyrolyzed wood have been investigated within the temperature range of 573-773 K and the oxygen concentration range of 2.25-36 vol %. These kinetics are, for instance, required for the design of a char combustion section in an integrated flash pyrolysis pilot plant.

  16. The influence of included minerals on the reactivity of chars prepared at low temperature in DFT

    Energy Technology Data Exchange (ETDEWEB)

    Hong Zhang; Jiaxing Fan; Wenxiu Pu; Ming Sun [China University of Mining and Technology, Xuzhou (China). School of Chemical Engineering

    2007-07-01

    In this paper four Chinese pulverized coals of different rank were separated into various density fractions with float-sink procedure. Two fractions of each coal, one for organic-rich, the other for organic with included mineral, were devolatized in a drop tube furnace at a temperature of 90{sup o}C and 1 vol% oxygen atmosphere. The reactivities of chars were measured non-isothermally in a thermal gravimetric analyser (TGA) in the range of 20-90{sup o}C. The results indicate that the role of included minerals in chars change with the rank of coals. For anthracites, minerals play catalytic effect during the combustion process, while for bituminous coals the opposite. Gas absorption studies with N{sub 2} at 77K indicate that their reactivity difference correlates with pore structure change. After a discussion about various factors affecting the formation process of chars, it was concluded that included minerals dilute and adsorb the liquid phase during pyrolysis. For anthracites, there is no or little liquid phase, minerals act as pore producer in coal matrix. For bituminous coals, the same effect of minerals cause the escape of the swelling gas inside the particles, leading to the formation of char cenospheres with less void and lower reactivity. 10 refs., 4 figs., 3 tabs.

  17. Accumulation of persistant pollutants in normal and dwarfed Arctic char (Salvelinus alpinus sp. complex)

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, J. (Uppsala Univ. (Sweden)); Larsson, P. (Lund Univ. (Sweden)); Klavins, M. (Inst. of Biology, Salaspils (Latvia))

    1993-01-01

    Two extreme growth fractions of introgressed sympatric populations of the Arctic char species complex from a Swedish lake were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of sum of polychlorinated biphenyl (PCB) congeners found and dominating DDT-compound than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass dilution of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish. 51 refs., 3 figs., 3 tabs.

  18. Time domain-nuclear magnetic resonance study of chars from southern hardwoods

    Science.gov (United States)

    Thomas Elder; Nicole Labbe; David Harper; Timothy Rials

    2006-01-01

    Chars from the thermal degradation of silver maple (Acer saccharinum), red maple (Acer rubrum), sugar maple (Acer saccharum), and white oak (Quercus spp.), performed at temperatures from 250 to 350 oC, were examined using time domain-nuclear magnetic resonance...

  19. Temperature induced development of porous structure of bituminous coal chars at high pressure

    Directory of Open Access Journals (Sweden)

    Natalia Howaniec

    2016-01-01

    Full Text Available The porous structure of chars affects their reactivity in gasification, having an impact on the course and product distribution of the process. The shape, size and connections between pores determine the mechanical properties of chars, as well as heat and mass transport in thermochemical processing. In the study the combined effects of temperature in the range of 973–1273 °K and elevated pressure of 3 MPa on the development of porous structure of bituminous coal chars were investigated. Relatively low heating rate and long residence time characteristic for the in-situ coal conversion were applied. The increase in the temperature to 1173 °K under pressurized conditions resulted in the enhancement of porous structure development reflected in the values of the specific surface area, total pore volume, micropore area and volume, as well as ratio of the micropore volume to the total pore volume. These effects were attributed to the enhanced vaporization and devolatilization, as well as swelling behavior along the increase of temperature and under high pressure, followed by a collapse of pores over certain temperature value. This proves the strong dependence of the porous structure of chars not only on the pyrolysis process conditions but also on the physical and chemical properties of the parent fuel.

  20. Thermal Conversion of Pine Wood Char to Carbon Nanomaterials in the Presence of Iron Nanoparticles

    Science.gov (United States)

    Sung Phil Mun; Zhiyong Cai; Fumiya Watanabe; Umesh P. Agarwal; Jilei. Zhang

    2012-01-01

    Southern yellow pine (Pinus taeda) wood char powder was thermally treated at 1,000:C in the presence of a 25-nm-size Fe nanoparticle catalyst. The thermally treated carbon materials were analyzed by Raman spectroscopy and high-resolution transmission electron microscopy. Well-aligned graphitic carbon structures with 15 to 17 layers on...

  1. Mineral-char interaction during gasification of high-ash coals in fluidized-bed gasification

    CSIR Research Space (South Africa)

    Oboirien, BO

    2011-09-01

    Full Text Available interface and less in the unaffected part. To establish this fact, the mapping of two Raman parameters ID/IG versus IV/IG was used. This study sought to evaluate the impact of melted mineral on parts of the chars generated at 960C and 30 min in oxygen...

  2. Ultrasonic Characterisation of Epoxy Resin/Polyethylene Terephthalate (PET Char Powder Composites

    Directory of Open Access Journals (Sweden)

    Imran ORAL

    2016-11-01

    Full Text Available This study is carried out in order to determine the elastic properties of the Epoxy Resin (ER / Polyethylene terephthalate (PET Char Powder Composites by ultrasonic wave velocity measurement method. Plastic waste was recycled as raw material for the preparation of epoxy composite materials. The supplied chars were mixed with epoxy resin matrix at weight percentages of 10 %, 20 % and 30 % for preparing ER/PET Char Powder (PCP composites. The effect of PET char powder on the elastic properties of ER/PCP composites were investigated by ultrasonic pulse-echo method. According to the obtained results, the composition ratio of 80:20 is the most appropriate composition ratio, which gave the highest elastic constants values for ER/PCP composites. On the other hand, the best electrical conductivity value was obtained for 70:30 composition ratio. It was observed that ultrasonic shear wave velocity correlated more perfectly than any other parameters with hardness.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12190

  3. Microanalysis of vitrous char and associated polymers: reference and ancient assemblages

    Science.gov (United States)

    Allue, E.; Bonnamy, S.; Courty, M. M.; Gispert I Guirado, F.

    2012-12-01

    Formation of vitrous char that occur in ancient charcoal assemblages have remained unsolved. Laboratory experiments refuted vitrification to resulting from high temperature charring of green or resinous wood. This puzzling problem has been refreshed by showing the association to the charcoal and vitrous char of plastics that were originally supposed to only be produced by petroleum industry. Extraction of similar polymers within geological glassy products from cosmic airbursts has suggested impact processes to possibly forming the carbonaceous polymorphs. The pulverisation at the ground in the Angles village (French Eastern Pyrenees) following the 2011 August 2nd high altitude meteor explosion of exotic debris with vitrous char and polymers, just alike the puzzling ones of the geological and archaeological records, has provided potential reference materials. We present here their microanalysis by Environmental SEM with EDS, Raman micro-spectrometry and FTIR, XRD, TEM, ICP-MS and isotope analyses. The characterization helps elucidating how the carbonaceous polymorphs formed by transient heating and transient high pressure of atmospheric aerosols. Under TEM the vesicular, dense, vitrous char show high structural organization with a dense pattern of nano-sized graphitized domains, metals and mineral inclusions. The coupled Raman-ESEM has allowed identifying a complex pattern at micro scales of ordered "D" peak at 1320-1350 cm-1 and the graphitic, ordered peak at 1576-1590 cm-1, in association to amorphous and poorly graphitic ordered carbon. The later occurs within plant cells that have been extracted from the dense vitrous char by performing controlled combustion under nitrogen up to 1000°C. In contrast, the brittle, vesicular vitrous char and the polymers encountered at the rear of the pulverised airburst debris reveal to be formed of agglutinated micro spherules of amorphous carbon with rare crystallized carbon nano-domains and scattered mineral inclusions. They

  4. Preparation and characterization of activated carbon from the char produced in the thermolysis of granulated scrap tyres.

    Science.gov (United States)

    López, F A; Centeno, T A; Rodríguez, O; Alguacil, E J

    2013-05-01

    The char produced in the thermolysis of granulated scrap tyres has few market outlets, reducing the economic viability of the thermolytic process. This paper reports the potential of this char as a low-cost precursor of porous carbons. The tyre-derived char was demineralized in either alkaline or acidic media to reduce its ash, zinc, sulfur, and silica contents. The lowest impurity content was achieved with an HNO3/H2O treatment. The resulting demineralized char was then subjected to activation by KOH or CO2. The Brunauer-Emmett-Teller (BET)-specific surface area of the activated carbon produced by the KOH treatment was 242 m2/g, whereas that of the CO2-activated carbon was 720 m2/g. The textural properties of the latter product were similar to those of some commercial activated carbons. The use of tyre-derived char as a precursor of porous carbons could render the thermolytic treatment of scrap tyres more economically attractive. Char produced in thermolysis of granulated scrap tyres has a few market outlets; in this paper an alternative for its use is presented. The char was converted into activated carbon with textural properties similar to those of some commercial activated carbons. This process could render the thermolytic treatment of scrap tyres more economically attractive.

  5. Proximate analyses and predicting HHV of chars obtained from cocracking of petroleum vacuum residue with coal, plastics and biomass.

    Science.gov (United States)

    Ahmaruzzaman, M

    2008-07-01

    Higher heating value (HHV) and analysis of chars obtained from cocracking of petroleum vacuum residue (XVR) with coal (SC), biomass (BG, CL) and plastics (PP, PS, BL) are important which define the energy content and determine the clean and efficient use of these chars. The main aim of the present study is to analyze the char obtained from cocracking in terms of their proximate analysis data and determination of the HHV of the chars. The char obtained from XVR+PP cocracking showed a HHV of 32.84 MJ/kg, whereas that from CL cracking showed a HHV of 18.52 MJ/kg. The experimentally determined heating values of the char samples obtained from cocracking have been correlated with the theoretical equation based on proximate analysis data. There exists a variety of correlations for predicting HHV from proximate analysis of fuels. Based upon proximate analysis data, the models were tested. The best results show coefficient of determination (R2) of 0.965 and average absolute and bias error of 3.07% and 0.41%, respectively. The heating values obtained from the model were in good agreement with that obtained by experiment. Proximate analysis of the chars obtained from the cocracking of XVR with coal, biomass and plastics showed that there exists a definite interaction of the reactive species, when they were cocracked together.

  6. Development of a Distributed Nutrient Sub-Model (NSM Version 1.0) for Watersheds - Kinetic Process Descriptions

    Science.gov (United States)

    2006-11-01

    attention to the role of watershed management in elevating N and P concentrations within soil leachates and runoff. The main factors influenc- ing...being subject to only dissolved transport, and moves through the soil profile with percolating water. In modeling , 3NO − ERDC/EL TR-06-12 22 the... leachates , the contri- bution of DON has been largely ignored or considered to be insignificant. However, recent research demonstrated that DON made up the

  7. Influence of molecular structure and adsorbent properties on sorption of organic compounds to a temperature series of wood chars.

    Science.gov (United States)

    Lattao, Charisma; Cao, Xiaoyan; Mao, Jingdong; Schmidt-Rohr, Klaus; Pignatello, Joseph J

    2014-05-06

    Chars from wildfires and soil amendments (biochars) are strong adsorbents that can impact the fate of organic compounds in soil, yet the effects of solute and adsorbent properties on sorption are poorly understood. We studied sorption of benzene, naphthalene, and 1,4-dinitrobenzene from water to a series of wood chars made anaerobically at different heat treatment temperatures (HTT) from 300 to 700 °C, and to graphite as a nonporous, unfunctionalized reference adsorbent. Peak suppression in the NMR spectrum by sorption of the paramagnetic relaxation probe TEMPO indicated that only a small fraction of char C atoms lie near sorption sites. Sorption intensity for all solutes maximized with the 500 °C char, but failed to trend regularly with N2 or CO2 surface area, micropore volume, mesopore volume, H/C ratio, O/C ratio, aromatic fused ring size, or HTT. A model relating sorption intensity to a weighted sum of microporosity and mesoporosity was more successful. Sorption isotherm linearity declined progressively with carbonization of the char. Application of a thermodynamic model incorporating solvent-water and char-graphite partition coefficients permitted for the first time quantification of steric (size exclusion in pores) and π-π electron donor-acceptor (EDA) free energy contributions, relative to benzene. Steric hindrance for naphthalene increases exponentially from 9 to 16 kJ/mol (∼ 1.6-2.9 log units of sorption coefficient) with the fraction of porosity in small micropores. π-π EDA interactions of dinitrobenzene contribute -17 to -19 kJ/mol (3-3.4 log units of sorption coefficient) to sorption on graphite, but less on chars. π-π EDA interaction of naphthalene on graphite is small (-2 to 2 kJ/mol). The results show that sorption is a complex function of char properties and solute molecular structure, and not very predictable on the basis of readily determined char properties.

  8. Application of the environmentally sensitive forest growth and mortality submodel, ESGM, for estimating the historic and future forest carbon budget for the Sooke Lake Watershed, British Columbia.

    Science.gov (United States)

    Trofymow, J. A.; Hember, R.; Smiley, B. P.; Morken, S.; Kurz, W. A.

    2016-12-01

    Forest resource managers require knowledge of how natural disturbances, harvest, land-use change, and climate change affect carbon (C) budgets of complex landscapes. In this study, a retrospective (1911-2012) forest C budget for the 8500 ha Sooke Lake watershed was developed based on forest inventories, disturbance, and stream monitoring data using the Canadian Forest Service's spatially-explicit Generic Carbon Budget Model (GCBM). This standard version of GCBM used species-specific volume-over-age curves and site indices to determine tree growth and thus does not explicitly account for environmental factors (climate, CO2, N deposition) that may affect trees and net ecosystem production (NEP). Therefore, a new submodel was developed for GCBM, ESGM, which uses empirical equations to account for influences of 8 environmental factors on tree growth and mortality, based on analysis of multi-decadal data from 19,777 field plots from western North America. Annual environmental variables were prepared (1910-2012) for input to GCBMesgm and temperature effects on decay rates were turned on in the GCBM soil submodel. In response to fires, harvesting, planting, and deforestation for drinking water reservoir expansions, the standard GCBM run showed over 100 years (1911, 1940, 1991, 2012) aboveground biomass C (262, 189, 148, 177 MgC/ha) and NEP (0.6, -1.3, 0.8, 2.3 Mg C/ha/yr) declined and then increased as harvest and deforestation ceased in 2002. From 1.5 -6.5% of terrestrial humified soil C losses (30,640 Mg C/100 yrs) were estimated to have been exported as dissolved organic carbon. Assuming no future disturbances, the standard GCBM run indicates NEP will peak at 2.64 MgC/ha/yr in 2024 and biomass C reach 1910 levels by 2075. Comparisons will be made between standard GCBM and GCBMesgmruns of the C budget for the historic period and for future climate scenarios (baseline, RCP4.5 and RCP8.5) from the CanESM2 GCM, to explore the potential implications of environmental change

  9. Nonlinear visco-elastic finite element analysis of porcelain veneers: a submodelling approach to strain and stress distributions in adhesive and resin cement.

    Science.gov (United States)

    Perillo, Letizia; Sorrentino, Roberto; Apicella, Davide; Quaranta, Alessandro; Gherlone, Enrico; Zarone, Fernando; Ferrari, Marco; Aversa, Raffaella; Apicella, Antonio

    2010-10-01

    To assess under load the biomechanical behavior of the cementing system of feldspathic vs alumina porcelain veneers. A 3D model of a maxillary central incisor, the periodontal ligament (PDL) and the alveolar bone was generated. Incisors restored with alumina and feldspathic porcelain veneers were compared to a natural sound tooth. Enamel, cementum, cancellous and cortical bone were considered isotropic elastic materials; conversely, dentin was designated as orthotropic. The nonlinear visco-elatic behavior of the PDL was considered. The adhesive layers were modelled using spring elements. A 50-N load at a 60-degree angle to the tooth's longitudinal axis was applied and validated. Stress concentration in the interfacial volumes of the main models was identified and submodelled in a new environment. Regarding tooth structure, strain concentrations were observed in the root dentin below the CEJ. As to the cement layer, tensile stresses concentrated in the palatal margin of the adhesive complex. Despite the effects on tooth deformation, the rigidity of the veneer did not affect the stress distributions in the cement layer or in the adhesive layers. In both cases, the palatal and cervical margins seemed to be the most stressed areas.

  10. Effect of torrefaction on the properties of rice straw high temperature pyrolysis char: Pore structure, aromaticity and gasification activity.

    Science.gov (United States)

    Chen, Handing; Chen, Xueli; Qin, Yueqiang; Wei, Juntao; Liu, Haifeng

    2017-03-01

    The influence of torrefaction on the physicochemical characteristics of char during raw and water washed rice straw pyrolysis at 800-1200°C is investigated. Pore structure, aromaticity and gasification activity of pyrolysis chars are compared between raw and torrefied samples. For raw straw, BET specific surface area decreases with the increased torrefaction temperature at the same pyrolysis temperature and it approximately increases linearly with weight loss during pyrolysis. The different pore structure evolutions relate to the different volatile matters and pore structures between raw and torrefied straw. Torrefaction at higher temperature would bring about a lower graphitization degree of char during pyrolysis of raw straw. Pore structure and carbon crystalline structure evolutions of raw and torrefied water washed straw are different from these of raw straw during pyrolysis. For both raw and water washed straw, CO 2 gasification activities of pyrolysis chars are different between raw and torrefied samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Characterization of adsorption of aqueous arsenite and arsenate onto charred dolomite in microcolumn systems.

    Science.gov (United States)

    Salameh, Yousef; Al-Muhtaseb, Ala'a H; Mousa, Hasan; Walker, Gavin M; Ahmad, Mohammad N M

    2014-01-01

    In this work, the removal of arsenite, As(III), and arsenate, As(V), from aqueous solutions onto thermally processed dolomite (charred dolomite) via microcolumn was evaluated. The effects of mass of adsorbent (0.5-2 g), initial arsenic concentration (50-2000 ppb) and particle size (dolomite in a microcolumn were investigated. It was found that the adsorption of As(V) and As(III) onto charred dolomite exhibited a characteristic 'S' shape. The adsorption capacity increased as the initial arsenic concentration increased. A slow decrease in the column adsorption capacity was noted as the particle size increased from>0.335 to 0.710-2.00 mm. For the binary system, the experimental data show that the adsorption of As(V) and As(III) was independent of both ions in solution. The experimental data obtained from the adsorption process were successfully correlated with the Thomas Model and Bed Depth Service Time Model.

  12. Synthesis and Application of a Novel Polyamide Charring Agent for Halogen-Free Flame Retardant Polypropylene

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2013-01-01

    Full Text Available A novel charring agent, poly(p-ethylene terephthalamide (PETA, for halogen-free flame retardant polypropylene was synthesized by using p-phthaloyl chloride (TPC and ethylenediamine through solution polycondensation at low temperature, and the effects of PETA on flame retardance of polypropylene (PP/IFR systems were studied. The experimental results showed that PETA could considerably enhance the fire retardant performance as proved by evidence of the increase of limiting oxygen index (LOI values, the results of UL-94 tests, and cone calorimeter tests (CCT. Fourier transform infrared spectroscopy (FTIR and scanning electron microscope (SEM demonstrated that an appropriate amount of PETA could react with PP/IFR system to form cross-link network; a more compact char layer could be formed which was responsible for the improved thermal and flame retardant properties of PP/IFR systems. However, the superfluous amount of PETA would play the negative role.

  13. The efficacy of high-throughput sequencing and target enrichment on charred archaeobotanical remains

    DEFF Research Database (Denmark)

    Nistelberger, H. M.; Smith, O.; Wales, Nathan

    2016-01-01

    The majority of archaeological plant material is preserved in a charred state. Obtaining reliable ancient DNA data from these remains has presented challenges due to high rates of nucleotide damage, short DNA fragment lengths, low endogenous DNA content and the potential for modern contamination...... different laboratories, presenting the largest HTS assessment of charred archaeobotanical specimens to date. Rigorous analysis of our data - excluding false-positives due to background contamination or incorrect index assignments - indicated a lack of endogenous DNA in nearly all samples, except for one....... It has been suggested that high-throughput sequencing (HTS) technologies coupled with DNA enrichment techniques may overcome some of these limitations. Here we report the findings of HTS and target enrichment on four important archaeological crops (barley, grape, maize and rice) performed in three...

  14. Transient behavior of devolatilization and char reaction during steam gasification of biomass.

    Science.gov (United States)

    Moon, Jihong; Lee, Jeungwoo; Lee, Uendo; Hwang, Jungho

    2013-04-01

    Steam gasification of biomass is a promising method for producing high quality syngas for polygeneration. During the steam gasification, devolatilization and char reaction are key steps of syngas production and the contributions of the two reactions are highly related to gasification conditions. In this study, the transient characteristics of devolatilization and char reaction in biomass steam gasification were investigated by monitoring cumulative gas production and composition changes in terms of reaction temperature and S/B ratio. Contribution of each reaction stage on the product gas yield was studied in detail. The results provide important insight for understanding the complex nature of biomass gasification and will guide future improvements to the biomass gasification process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. EFFECT OF CALCIUM ADDITION ON THE DEFLUORIDATION CAPACITY OF BONE CHAR

    DEFF Research Database (Denmark)

    Jacobsen, P.; Dahi, Elian

    1997-01-01

    Dosage of small amounts of calcium chloride to fluoride water prior to contact with bone char which has already been saturated with fluoride is shown to provide an additional fluoride removal capacity. The additionally obtained removal capacity increases with slower filtration velocities and incr......Dosage of small amounts of calcium chloride to fluoride water prior to contact with bone char which has already been saturated with fluoride is shown to provide an additional fluoride removal capacity. The additionally obtained removal capacity increases with slower filtration velocities...... to be capable of reducing the fluoride concentration form 10 to about 0.5 mgF/L. The additionally saturated column is shown to be regenerated by simple adjustment of the pH of the water to 11 and allowing to flow for a few bed volumes. The useful regeneration capacity, where the fluoride concentration...

  16. Time resolved quantitative imaging of charring in materials at temperatures above 1000 K

    Science.gov (United States)

    Böhrk, Hannah; Jemmali, Raouf

    2016-07-01

    A device is presented allowing for in situ investigation of chemically changing materials by means of X-ray imaging. A representative cork ablator sample, additionally instrumented with thermocouples, is encapsulated in an evacuated cell heating a sample surface with a heat flux of 230 kW/m2. The images show the sample surface and the in-depth progression of the char front dividing the char layer from the virgin material. Correlating the images to thermocouple data allows for the deduction of a reaction temperature. For the representative cork ablator investigated at the present conditions, the progression rate of the pyrolysis layer is determined to 0.0285 mm/s and pyrolysis temperature is 770 or 737 K, depending on the pre-existing conditions. It is found that the novel device is ideally suited for volume process imaging.

  17. SOLID CHAR CHARACTERIZATION FROM EFFECT OF RADIATION TIME STUDY ON MICROWAVE ASSISTED PYROLYSIS OF KITCHEN WASTE

    Directory of Open Access Journals (Sweden)

    ZAKIUDDIN B. JANURI

    2016-07-01

    Full Text Available Increment of population in a country influenced the generation of high amount solid waste that being sent to the landfill. High proportions of solid waste were contributed by the kitchen / food waste. Currently, conventional method used for final disposal of these wastes was through landfilling or through direct incineration. However, high moisture content at 90% stretched a dilemma for both disposal method which leachate was generated from the landfill and furthermore, it cannot be achieved or limited by using incineration due to the humidity limitation of the incinerator. In this research, microwave assisted pyrolysis introduced was not only to dispose the waste, at the same time can recover valuable material from the kitchen waste. Effect of radiation time was studied at range 10 min to 60 min in the process in order to get optimum process condition. Meanwhile, other parameter such as microwave power level, sample weight loading and microwave absorber ratio were set constant at 1000W, 200g, and 20%wt/wt respectively. High conversion of kitchen waste was transformed into solid char was obtained at low radiation time with conversion >80%. Solid char obtained was analysed and had good fuel properties with calorific value >16000 J/kg. Solid char obtained also has high carbon content and low oxygen content which indicated the pyrolysis had fully transform the kitchen waste to carbon solid char and contained low hydrocarbon chemical content. In a nutshell, the microwave assisted pyrolysis can be implemented to treat the kitchen waste and at the same time can recover the valuable material which has the potential to become solid fuel.

  18. Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

    Science.gov (United States)

    Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

    2016-04-01

    In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

  19. The study of microspheric mineral inclusions of fly ash char particles

    Energy Technology Data Exchange (ETDEWEB)

    V.V. Yumashev; N.N. Anshits; L.I. Timoshenko; V.G. Samoylov; A.I. Titkov; A.G. Anshits [Institute of Chemistry & Chemical Technology SB RAS, Krasnoyarsk (Russian Federation)

    2005-07-01

    The structure and morphology of carbon matrix and mineral inclusions of char particles in fly ash from burning two coals of different metamorphization stages were studied by methods of chemical analysis, optical and SEM microscopy. Char particles were separated by dry magnetic separation, grain-size classification and separation in the hexane-water system. The content of carbon in narrow fractions of the generated products makes 42-84 wt%, the specific surface varies in a range of 8-155 m{sup 2}/g, the content of Fe{sub 2}O{sub 3} in the ash residue lays in an interval of 3.2-19.5 wt%. It was shown, that at burning coals with a high volatile component content (V{sup daf}= 43.5 wt. %), char particles of a spherical form with a maximum globule distribution of 0.2-0.4 mm and a specific surface of 91-155 m{sup 2}/g are formed. High rank coals with V{sup daf}= 25 wt% form particles of the wrong angular form with lamellar macroporous structure and a specific surface of 8-10 m{sup 2}/g during the burning process. In all studied products microspheres of a mineral part with maximum distribution of 1.5-2.0 {mu}m are located in a carbon matrix. Thus, the most part of coal mineral component with high value of V{sup daf} forms thin films on a carbon matrix surface. It is established, that the carbon content in char particles is monotonously reduced with an increase in Fe{sub 2}O{sub 3} content in ash residue. At the same concentration of Fe{sub 2}O{sub 3} in the ash residue the content of carbon for samples with the advanced microporous structure is lower by 16-17 wt.%. 12 refs., 4 figs., 4 tabs.

  20. A comparison of coal char reactivity determined from thermogravimetric and laminar flow reactor experiments

    Energy Technology Data Exchange (ETDEWEB)

    Zolin, A.; Jensen, A.; Pedersen, L.S.; Dam-Johansen, K.; Toerslev, P. [Technical University of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

    1998-03-01

    The reactivity of nine different coals ranking from subbituminous to low-volatile bituminous has been studied by thermogravimetric analysis (TGA). At a standard set of conditions a qualitative fuel reactivity classification (ranking) with respect to one of the coals, Cerrejon, is presented. Particle reaction rates per unit external surface area and a normalized reactivity index based on raw experimental data were used as reactivity parameters to compare the fuels. The TGA chars were prepared at 900{degree}C with 15 min holding time and then combusted in a 20 mol % O{sub 2} environment at several temperatures in the range 450-650{degree}C. TGA reaction rate data were adequately interpreted by a random pore model. However, at 650{degree}C it is believed that particle ignition gave rise to a char reaction rate behavior that the model was incapable of describing properly. Except for two Southern Hemisphere coals, the reactivity ranking obtained with the TGA apparatus at a combustion temperature of 550{degree}C agrees well with a corresponding classification based on experiments carried out in another study with a laminar flow reactor (LFR) at {approximately} 1400{degree}C. The maximum difference in reaction rates based on external surface area between the coal chars in the low-temperature TGA experiments was 1 order of magnitude higher than in the high-temperature LFT experiments, due to the increasing effect of pore diffusion and thermal annealing of the coal chars in the LFR tests. The similarity in the reactivity ranking obtained for the Northern Hemisphere coals from both reactor systems indicates that a ranking can be performed by thermogravimetric analysis. This provides a simple means for determining a fuel reactivity ranking that could be applied to full scale suspension fired plants. 28 refs., 8 figs., 4 tabs.

  1. Impact of pretreatment on defluoridation of drinking water by bone char adsorption

    OpenAIRE

    Adam Teusner; Rhett Butler; Pierre Le Clech

    2016-01-01

    Fluoride concentrations in drinking water in excess of 1.5 mg L-1 are unsafe for human consumption. To reduce excess fluoride intake, developing countries must use low-cost, point-of-use defluoridation techniques. Although previous work has extensively assessed defluoridation using bone char (BC), most of the advanced studies have been based on the use of fluoridated distilled water as a feed solution. In the present study, BC columns were challenged with a range of model solutions, mimicking...

  2. Water quality and Sanitation status: A study on Char land of Bhuapur upazila under Tangail district

    OpenAIRE

    Islam, M.S.; Sarker, B.C.; Mahmud, N.A.; Saifullah, A.S.M.

    2013-01-01

    The study was aimed to review the damage of sanitation facilities; since Char land’s dwellers faces manifold challenges concerning sanitation, hygiene and water during flood. It also explored the possibilities of overcoming the negative impacts of floods on sources of safe drinking water and sanitation. The study result shows that, about 54% of the overall latrines were included ring slab with water seal, pit latrine, bush or hanging toilet of the flood affected people during the flood. Aroun...

  3. Detection of pre-charring optical behavior at a laser catheter-tip in blood: ex vivo and in vivo study

    Science.gov (United States)

    Takahashi, Mei; Ito, Arisa; Kajihara, Takuro; Arai, Tsunenori

    2011-03-01

    We studied a pre-charring optical behavior of blood at a laser catheter-tip during a red laser irradiation (663 nm, CW) with around 50 W/cm2 in blood to prevent charring at the laser catheter-tip. The laser irradiated red-blood-cell shape changes were microscopically observed. A round formation, aggregation, and hemolysis were found until blood charring (ex vivo). A time-history of diffuse-reflected light power and transmitted light power from a thin blood layer which was irradiated by the red laser were measured with microscope optics to investigate the charring process. The diffusereflected light power decreased following a gentle peak before the charring. This decrease indicated the pre-charring behavior which might be induced by scattering and absorption changes due to red-blood-cell degenerations described above. Using the laser catheter located in porcine heart, we successfully detected the pre-charring behavior by a backscattering light power (in vivo). We demonstrated charring prevention availability with the laser power control (ex vivo). We think that the backscattering light power measurement and laser power control via the laser catheter might be useful to detect pre-charring behavior, and to prevent the charring for therapeutic laser irradiation in blood under catheterization such as arrhythmia treatment with photodynamic therapy.

  4. CO{sub 2} and steam gasification of a grapefruit skin char

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Montesinos, F.; Cordero, T.; Rodriguez-Mirasol, J.; Rodriguez, J.J. [University of Pinar del Rio, Pinar del Rio (Cuba). Dept. of Chemistry

    2002-03-01

    A kinetic study on the gasification of carbonized grapefruit (Citrus Aurantium) skin with CO{sub 2} and with steam is presented. The chars from this agricultural waste show a comparatively high reactivity, which can be mostly attributed to the catalytic effect of the inorganic matter. The ash content of the carbonized substrate used in this work falls around 15% (db) potassium being the main metallic constituent. The reactivity for both, CO{sub 2} and steam gasification, increases at increasing conversion and also does the reactivity per unit surface area, consistently with the aforementioned catalytic effect. Lowering the ash content of the char by acid washing leads to a decrease of reactivity thus confirming the catalytic activity of the inorganic matter present in the starting material. Saturation of this catalytic effect was not detected within the conversion range investigated covering in most cases up to 0.85 - 0.9. Apparent activation energy values within the range of 200-250 kJ/mol have been obtained for CO{sub 2} gasification whereas the values obtained for steam gasification fall mostly between 130 and 170 kJ/mol. These values become comparable with the reported in the literature for other carbonaceous raw materials including chars from biomass residues and coals under chemical control conditions. 28 refs., 6 figs., 5 tabs.

  5. Pyrolysis of hornbeam (Carpinus betulus L.) sawdust: Characterization of bio-oil and bio-char.

    Science.gov (United States)

    Moralı, Uğur; Yavuzel, Nazan; Şensöz, Sevgi

    2016-12-01

    Slow pyrolysis of hornbeam (Carpinus betulus L.) sawdust was performed to produce bio-oil and bio-char. The operational variables were as follows: pyrolysis temperature (400-600°C), heating rate (10-50°Cmin(-1)) and nitrogen flow rate (50-150cm(3)min(-1)). Physicochemical and thermogravimetric characterizations of hornbeam sawdust were performed. The characteristics of bio-oil and bio-char were analyzed on the basis of various spectroscopic and chromatographic techniques such as FTIR, GC-MS, 1H NMR, SEM, BET. Higher heating value, density and kinematic viscosity of the bio-oil with maximum yield of 35.28% were 23.22MJkg(-1), 1289kgm(-3) and 0.6mm(2)s(-1), respectively. The bio-oil with relatively high fuel potential can be obtained from the pyrolysis of the hornbeam sawdust and the bio-char with a calorific value of 32.88MJkg(-1) is a promising candidate for solid fuel applications that also contributes to the preservation of the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Characterization of red mud-epoxy intumescent char using surface imaging and micro analysis

    Energy Technology Data Exchange (ETDEWEB)

    Arogundade, A. I., E-mail: ajiunolorioba@gmail.com; Megat-Yusoff, P. S. M., E-mail: puteris@petronas.com.my; Faiz, A. [Department of Mechanical Engineering, Universiti Tecknologi Petronas (Malaysia); Bhat, A. H. [Department of Fundamental and Applied Science, Universiti Tecknologi Petronas (Malaysia)

    2015-07-22

    In this study, red mud (RM), an oxide waste was proposed as reinforcing, synergistic filler for the traditional epoxy intumescent coating (IC). 5.5 wt% of acid-modified and unmodified red mud were introduced into the basic intumescent formulation of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). In order to predict effect of modification on its suitability, Field emission electron scanning microscopy and Fourier transform infra red were used to obtain detailed characteristics such as the cell size, pore distribution, homogeneity and chemical composition of the red mud-epoxy carbonaceous char. Both acid-modified and unmodified RM-filled ICs produced chars with smaller and more closely packed cells compared to chars from the unfilled coating. Both coating types had hard carbonaceous metal phosphate coverings that could act as heat barriers. The unmodified red mud was found to be antagonistic to the intumescent action with an expansion of only 2 times the initial thickness. The leached, low iron-red mud produced an expansion of 15 times the initial thickness, but possessed a hollow interior. From these findings, it may be deduced that while acid leaching of red mud may improve intumescent expansion, it would be necessary to optimize the percent filler loading to improve residual mass.

  7. Effects of Bio-char on Soil Microbes in Herbicide Residual Soils

    Directory of Open Access Journals (Sweden)

    WANG Gen-lin

    2015-10-01

    Full Text Available Effects of biological carbon (bio-char on soil microbial community were studied by pot experiments simulating long residual herbicide residues in soil environment, which clarifed the improvement of biochar and its structural properties on soil microenvironment. The results showed that fungi and actinomycetes had the same effect tendency within 0~0.72 mg·kg-1 in clomazone residue which increased the role of stimulation with crop growth process prolonged, especially in high residue treatment, but strong inhibitory effect on bacteria community was occured early which returned to normal until sugar beet growth to fiftieth day. Soil fungi community decreased with bio-char adding, but had no significant difference with the control. When clomazone residue in soil was below 0.24 mg·kg-1, soil actinomycetes community was higher than control without bio-char, bacteria increased first and then reduced after adding carbon as below 0.12 mg·kg-1. Biochar was ‘deep hole’ structure containing C, O, S and other elements. The results showed that a certain concentration clomazone residue in soil would stimulate soil fungi and actinomycetes to grow. After adding the biochar, the inhibition effect of high herbicides residual on bacterial would be alleviated.

  8. Characterization and Activation Study of Black Chars Derived from Cellulosic Biomass Pyrolyzed at Very High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Gallego, Nidia C. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    The State of Tennessee, in partnership with the University of Tennessee (UT) and the Oak Ridge National Laboratory (ORNL), has created the RevV! Manufacturing voucher program to help Tennessee manufacturers gain access to the world-class resources at ORNL. As a part of this program, ORNL was working with Proton Power, Inc. (PPI), a rapidly growing company located in Lenoir City, Tennessee. PPI has developed a patented renewable energy system that uses biomass and waste sources to produce inexpensive hydrogen gas or synthetic fuels which are economically competitive with fossil fuels. The pyrolysis process used by PPI in their manufacturing chain generates significant amounts of black carbon char as by-product. The scope of ORNL collaboration with PPI was assessing the black carbon char as a potential feedstock for activated carbon production, as this could be a potentially new revenue stream. During 2015-2016 ORNL received eight char samples from PPI and characterized their initial properties, simulated their physical activation by carbon dioxide, prepared gram-size samples of physically activated carbons, and characterized their surface and porosity properties. This report presents a summary of the work methods employed and the results obtained in the collaborative project between ORNL and PPI.

  9. Temperature Trends in Coal Char Combustion under Oxy-fuel Conditions for the Determination of Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Samira [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hecht, Ethan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    Oxy-fuel combustion technology with carbon capture and storage could significantly reduce global CO2 emissions, a greenhouse gas. Implementation can be aided by computational fluid dynamics (CFD) simulations, which require an accurate understanding of coal particle kinetics as they go through combustion in a range of environments. To understand the kinetics of pulverized coal char combustion, a heated flow reactor was operated under a wide range of experimental conditions. We varied the environment for combustion by modifying the diluent gas, oxygen concentration, gas flow rate, and temperature of the reactor/reacting gases. Measurements of reacting particle temperatures were made for a sub-bituminous and bituminous coal char, in environments with CO2 or N2 as the diluent gas, with 12, 24, and 36 vol-% oxygen concentration, at 50, 80, 100, and 200 standard liters per minute flowing through the reactor, reactor temperatures of 1200, 1400 K, at pressures slightly above atmospheric. The data shows consistent increasing particle temperature with increased oxygen concentration, reactor temperature and higher particle temperatures for N2 diluent than CO2. We also see the effects of CO2 gasification when different ranks of coal are used, and how the reduction in the temperature due to the CO2 diluent is greater for the coal char that has higher reactivity. Quantitative measurements for temperature are not yet complete due to ongoing calibration of detection systems.

  10. Sugars and char formation on subcritical water hydrolysis of sugarcane straw.

    Science.gov (United States)

    Lachos-Perez, D; Tompsett, G A; Guerra, P; Timko, M T; Rostagno, M A; Martínez, Julian; Forster-Carneiro, T

    2017-11-01

    Subcritical water has potential as an environmentally friendly solvent for applications including hydrolysis, liquefaction, extraction, and carbonization. Here, we report hydrolysis of sugarcane straw, an abundant byproduct of sugar production, in a semi-continuous reactor at reaction temperatures ranging from 190 to 260°C and at operating pressures of 9 and 16MPa. The target hydrolysis products were total reducing sugars. The main products of sugarcane straw hydrolysis were glucose, xylose, arabinose, and galactose in addition to 5- hydroxymethylfurfural and furfural as minor byproducts. Fourier transform infrared spectroscopy and thermogravimetric analysis provided additional information on the surface and bulk composition of the residual biomass. Char was present on samples treated at temperatures equal to and greater than 190°C. Samples treated at 260°C contained approximately 20wt% char, yet retained substantial hemicellulose and cellulose content. Hydrolysis temperature of 200°C provided the greatest TRS yield while minimizing char formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Characterization of red mud-epoxy intumescent char using surface imaging and micro analysis

    Science.gov (United States)

    Arogundade, A. I.; Megat-Yusoff, P. S. M.; Bhat, A. H.; Faiz, A.

    2015-07-01

    In this study, red mud (RM), an oxide waste was proposed as reinforcing, synergistic filler for the traditional epoxy intumescent coating (IC). 5.5 wt% of acid-modified and unmodified red mud were introduced into the basic intumescent formulation of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). In order to predict effect of modification on its suitability, Field emission electron scanning microscopy and Fourier transform infra red were used to obtain detailed characteristics such as the cell size, pore distribution, homogeneity and chemical composition of the red mud-epoxy carbonaceous char. Both acid-modified and unmodified RM-filled ICs produced chars with smaller and more closely packed cells compared to chars from the unfilled coating. Both coating types had hard carbonaceous metal phosphate coverings that could act as heat barriers. The unmodified red mud was found to be antagonistic to the intumescent action with an expansion of only 2 times the initial thickness. The leached, low iron-red mud produced an expansion of 15 times the initial thickness, but possessed a hollow interior. From these findings, it may be deduced that while acid leaching of red mud may improve intumescent expansion, it would be necessary to optimize the percent filler loading to improve residual mass.

  12. Documentation & Condition Mapping for Restoration & Revitalisation of Historic Sheesh Mahal & Char Bagh Complex in Patiala (punjab), India

    Science.gov (United States)

    Dasgupta, S.

    2017-08-01

    Located in the Northern State of Punjab, the historic city of Patiala has always been a centre of culture in north India, and has seen the evolution of its own distinct style of architecture with Rajput and Mughal influences. The city is renowned for its rich architectural heritage, Music, Craft, Sports and Cuisine. The fourth Maharaja Narinder Singh was a great patron of art, architecture and music and it was during his time that several palaces like the Moti Bagh Palace, Sheesh Mahal and Banasur Bagh were designed followed by Baradari Palace. Later it was Maharaja Bhupinder Singh (1900-1938) who made Patiala State famous with his lavish lifestyle.This paper describes the process followed for Documentation and condition assessment of the historic Sheesh Mahal & Char Bagh Complex in order to restore and revitalise the palace building and the Mughal garden. The exercise included Archival research, Field surveys, Condition Mapping, inventories using traditional methods as well as GIS and preparation of restoration & conservation solutions along with post conservation management manual. The Major challenges encountered were identifying the correct documentation methodology for mapping as well as managing the large database generated on site. The Documentation and Mapping was used as a significant tool to guide towards the conservation and Management strategy of the complex.

  13. DOCUMENTATION & CONDITION MAPPING FOR RESTORATION & REVITALISATION OF HISTORIC SHEESH MAHAL & CHAR BAGH COMPLEX IN PATIALA (PUNJAB, INDIA

    Directory of Open Access Journals (Sweden)

    S. Dasgupta

    2017-08-01

    Full Text Available Located in the Northern State of Punjab, the historic city of Patiala has always been a centre of culture in north India, and has seen the evolution of its own distinct style of architecture with Rajput and Mughal influences. The city is renowned for its rich architectural heritage, Music, Craft, Sports and Cuisine. The fourth Maharaja Narinder Singh was a great patron of art, architecture and music and it was during his time that several palaces like the Moti Bagh Palace, Sheesh Mahal and Banasur Bagh were designed followed by Baradari Palace. Later it was Maharaja Bhupinder Singh (1900–1938 who made Patiala State famous with his lavish lifestyle.This paper describes the process followed for Documentation and condition assessment of the historic Sheesh Mahal & Char Bagh Complex in order to restore and revitalise the palace building and the Mughal garden. The exercise included Archival research, Field surveys, Condition Mapping, inventories using traditional methods as well as GIS and preparation of restoration & conservation solutions along with post conservation management manual. The Major challenges encountered were identifying the correct documentation methodology for mapping as well as managing the large database generated on site. The Documentation and Mapping was used as a significant tool to guide towards the conservation and Management strategy of the complex.

  14. Determination of the intrinsic reactivities for carbon dioxide gasification of rice husk chars through using random pore model.

    Science.gov (United States)

    Gao, Xiaoyan; Zhang, Yaning; Li, Bingxi; Zhao, Yijun; Jiang, Baocheng

    2016-10-01

    Rice husk is abundantly available and environmentally friendly, and char-CO2 gasification is of great importance for the biomass gasification process. The intrinsic reaction rates of carbon dioxide gasification with rice husk chars derived from different pyrolysis temperatures were investigated in this study by conducting thermogravimetric analysis (TGA) measurements. The effects of gasification temperature and reactant partial pressure on the char-CO2 gasification were investigated and the random pore model (RPM) was used to determine the intrinsic kinetic parameters based on the experimental data. The results obtained from this study show that the activation energy, reaction order and pre-exponential factor varied in the ranges of 226.65-232.28kJ/mol, 0.288-0.346 and 2.38×10(5)-2.82×10(5)1/sPa(n) for the rice husk chars pyrolyzed at 700-900°C, respectively. All the determination coefficients between the RPM predictions and experimental results were higher than 0.906, indicating the RPM is reliable for determining and evaluating the intrinsic reactivities of rice husk chars. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. A Study on the Applicability of Kinetic Models for Shenfu Coal Char Gasification with CO2 at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Jinsheng Gao

    2009-07-01

    Full Text Available In this paper, measurements of the CO2 gasification kinetics for two types of Shenfu coal chars, which were respectively prepared by slow and rapid pyrolysis at temperatures of 950 °C and 1,400 °C, were performed by an isothermal thermo-gravimetric analysis under ambient pressure and elevated temperature conditions. Simultaneously, the applicability of the kinetic model for the CO2 gasification reaction of Shenfu coal chars was discussed. The results showed: (i the shrinking un-reacted core model was not appropriate to describe the gasification reaction process of Shenfu coal chars with CO2 in the whole experimental temperature range; (ii at the relatively low temperatures, the modified volumetric model was as good as the random pore model to simulate the CO2 gasification reaction of Shenfu coal chars, while at the elevated temperatures, the modified volumetric model was superior to the random pore model for this process; (iii the integral expression of the modified volumetric model was more favorable than the differential expression of that for fitting the experimental data. Moreover, by simply introducing a function: A = A★exp(ft, it was found that the extensive model of the modified volumetric model could make much better predictions than the modified volumetric model. It was recommended as a convenient empirical model for comprehensive simulation of Shenfu coal char gasification with under conditions close to those of entrained flow gasification.

  17. Synthesis and characterization of poly (dihydroxybiphenyl borate) with high char yield for high-performance thermosetting resins

    Science.gov (United States)

    Wang, Shujuan; Xing, Xiaolong; Li, Jian; Jing, Xinli

    2018-01-01

    The objective of the current work is to synthesize novel boron-containing polymers with excellent thermal resistance, and reveal the structure and the reason for the high char yield. Thus, poly (dihydroxybiphenyl borate) (PDDB) with a more rigid molecular chain, was successfully synthesized using 4,4‧-dihydroxybiphenyl and boric acid. Structural characterizations of the prepared PDDB were performed via NMR, FTIR, XPS, and XRD analyses. The results reveal that PDDB consists of aromatic, Phsbnd Osbnd B and Bsbnd Osbnd B structures as well as a small number of boron hydroxyl and phenolic hydroxyl groups. PDDB shows good solubility in strong polar solvents, which is of great importance for the modification of thermosetting resins. TGA combined with DSC were employed to evaluate the thermal properties of PDDB, and increases in the glass transition temperature (Tg) and char yield were observed with increased boron content. Tg and char yield of PDDB (800 °C, nitrogen atmosphere) reached up to 219 °C and 66.5%, respectively. PDDB was extensively characterized during pyrolysis to reveal the high char yield of PDDB. As briefly discussed, the boron oxide and boron carbide that formed during pyrolysis play a crucial role in the high char yield of PDDB, which reduces the release of volatile carbon dioxide and carbon. This research suggests that PDDB has great potential as a novel modified agent for the improvement of the comprehensive performance of thermosetting resins to broaden their applicability in the field of advanced composites.

  18. Effect of Kaolin Clay and Alumina on Thermal Performance and Char Morphology of Intumescent fire retardant coating

    Directory of Open Access Journals (Sweden)

    aziz Hammad

    2014-07-01

    Full Text Available Intumescent fire retardant coating (IFRC have been developed by using ammonium polyphosphate, expandable graphite, melamine, boric acid, kaolin clay and alumina as fillers bound together with epoxy resin and cured with the help of curing agent. Five different formulations were developed with and without using fillers. Cured samples were burned in furnace at 500°C for 2h for char expansion. Bunsen burner test was performed for 1h using UL-94 vertical burning test to investigate the thermal performance of IFRC. The resultant char obtained after burning of coated samples were characterized by using field emission scanning electron microscopy for char morphology. Char composition was analyzed by using fourier transform infrared spectroscopy. Thermogravimetric analysis was carried out to investigate the residual weight of coating. Results showed that formulation with 0.5 weight % of kaolin clay and 0.5 weight % of alumina provide best thermal performance, uniform and multi-porous char structure with high anti-oxidation property.

  19. Physico-chemical characterization of metal-doped bone chars and their adsorption behavior for water defluoridation

    Science.gov (United States)

    Rojas-Mayorga, C. K.; Bonilla-Petriciolet, A.; Silvestre-Albero, J.; Aguayo-Villarreal, I. A.; Mendoza-Castillo, D. I.

    2015-11-01

    New bone chars for fluoride adsorption from drinking water have been synthetized via metallic doping using aluminum and iron salts. A detailed statistical analysis of the metal doping process using the signal-to-noise ratios from Taguchi's experimental designs and its impact on the fluoride adsorption properties of modified bone chars have been performed. The best conditions, including the proper metallic salt, for metal doping were identified to improve the fluoride uptakes of modified bone chars. Results showed that the fluoride adsorption properties of bone chars can be enhanced up to 600% using aluminum sulfate for the surface modification. This aluminum-based adsorbent showed an adsorption capacity of 31 mg/g, which outperformed the fluoride uptakes reported for several adsorbents. Surface interactions involved in the defluoridation process were established using FTIR, DRX and XPS analysis. Defluoridation using the metal-doped bone chars occurred via an ion exchange process between fluoride ions and the hydroxyl groups on the adsorbent surface, whereas the Al(OH)xFy, FexFy, and CaF2 interactions could play also an important role in the removal process. These metal-doped adsorbents anticipate a promising behavior in water treatment, especially in developing countries where the efficiency - cost tradeoff is crucial for implementing new defluoridation technologies.

  20. Investigation on the fast co-pyrolysis of sewage sludge with biomass and the combustion reactivity of residual char.

    Science.gov (United States)

    Deng, Shuanghui; Tan, Houzhang; Wang, Xuebin; Yang, Fuxin; Cao, Ruijie; Wang, Zhao; Ruan, Renhui

    2017-09-01

    Gaining the valuable fuels from sewage sludge is a promising method. In this work, the fast pyrolysis characteristics of sewage sludge (SS), wheat straw (WS) and their mixtures in different proportions were carried out in a drop-tube reactor. The combustion reactivity of the residual char obtained was investigated in a thermogravimetric analyzer (TGA). Results indicate that SS and WS at different pyrolysis temperatures yielded different characteristic gas compositions and product distributions. The co-pyrolysis of SS with WS showed that there existed a synergistic effect in terms of higher gas and bio-oil yields and lower char yield, especially at the WS adding percentage of 80wt%. The addition of WS to SS increased the carbon content in the SS char and improved char porous structures, resulting in an improvement in the combustion reactivity of the SS char. The research results can be used to promote co-utilization of sewage sludge and biomass. Copyright © 2017. Published by Elsevier Ltd.

  1. Cd(II) adsorption on various adsorbents obtained from charred biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Li Zhenze, E-mail: lazyhero@live.cn [GSGES, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Katsumi, Takeshi [GSGES, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Imaizumi, Shigeyoshi [Dep. Adv. Interdiscip. Sci., Utsunomiya University, Yoto, Utsunomiya 321-8585 (Japan); Tang Xiaowu [MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058 (China); Inui, Toru [GSGES, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)

    2010-11-15

    Cadmium could cause severe toxicant impact to living beings and is especially mobile in the environment. Biomass is abundant and effective to adsorb heavy metals, but is easy to be decomposed biologically which affects the reliability of long-run application. Several biomasses were charred with and without additives at temperatures less than 200 deg. C in this study. The prepared adsorbents were further testified to remove Cd(II) from aqueous solution. Equilibrium and kinetic studies were performed in batch conditions. The effect of several experimental parameters on the cadmium adsorption kinetics namely: contact time, initial cadmium concentration, sorbent dose, initial pH of solution and ionic strength was evaluated. Kinetic study confirmed (1) the rapid adsorption of Cd(II) on GC within 10 min and (2) the following gradual intraparticle diffusion inwards the sorbent at neutral pH and outwards at strong acidic solution. The grass char (GC) was selected for further test according to its high adsorption capacity (115.8 mg g{sup -1}) and affinity (Langmuir type isotherm). The Cd(II) removal efficiency was increased with increasing solution pH while the highest achieved at sorbent dosage 10.0 g L{sup -1}. The ionic strength affects the sorption of Cd(II) on GC to a limited extent whereas calcium resulted in larger competition to the sorption sites than potassium. Spectroscopic investigation revealed the adsorption mechanisms between Cd(II) and surface functional groups involving amine, carboxyl and iron oxide. The long-term stability of the pyrolyzed grass char and the potential application in engineering practices were discussed.

  2. Effects of pyrolysis conditions on yield of bio-chars from pine chips

    Science.gov (United States)

    Qiangu Yan; Hossein Toghiani; Fei Yu; Zhiyong Cai; Jilei Zhang

    2011-01-01

    The influences of temperature, heating rate, purge gas type, and flow rate on the yield of chars produced from pyrolyzing southern pine chips were investigated. Pyrolysis temperatures were between 450°C and 1,000°C, with heating rates of 0.5°C/min, 1.0°C/min, 10°C/min, 30°C/min, 50°C/min, and 100°C/min. Purge gases, nitrogen (N2), hydrogen (H

  3. Oil production by entrained pyrolysis of biomass and processing of oil and char

    Science.gov (United States)

    Knight, James A.; Gorton, Charles W.

    1990-01-02

    Entrained pyrolysis of lignocellulosic material proceeds from a controlled pyrolysis-initiating temperature to completion of an oxygen free environment at atmospheric pressure and controlled residence time to provide a high yield recovery of pyrolysis oil together with char and non-condensable, combustible gases. The residence time is a function of gas flow rate and the initiating temperature is likewise a function of the gas flow rate, varying therewith. A controlled initiating temperature range of about 400.degree. C. to 550.degree. C. with corresponding gas flow rates to maximize oil yield is disclosed.

  4. Type of litter determines the formation and properties of charred material during wildfires

    Science.gov (United States)

    Chavez, Bruno; Fonturbel, M. Teresa; Salgado, Josefa; García-Oliva, Felipe; Vega, Jose A.; Merino, Agustin

    2014-05-01

    Wildfire is one of the most important disturbances all over the World, affecting both the amount and composition of forest floor and mineral soils. In comparison with unburnt areas, wildfire-affected forest floor usually shows lower contents of labile C compounds and higher concentrations of recalcitrant aromatic forms. These changes in composition can have important impact on biogeochemical cycles and therefore ecosystem functions. Although burning of different types of litter can lead to different amount and types of pyrogenic compounds, this aspect has not been evaluated yet. The effect of wildfire on SOM composition and stability were evaluated in five major types of non-wood litter in Mediterranean ecosystems: Pinus nigra, E. arborea, P. pinaster, U. europaeus and Eucalyptus globulus. In each of these ecosystems, forest floor samples from different soil burn severities were sampled. Soil burnt severities were based on visual signs of changes in forest floor and deposition of ash. Pyrogenic carbon quality were analysed using elementary analysis, solid-state 13 C nuclear magnetic resonance spectroscopy, Reflectance Infrared Fourier Transform (FTIR) and thermal analysis (simultaneous DSC-TG). The study showed that the different types of litter influenced the formation and characteristics of charred material. They differed in the temperature at which they start to be formed, the amounts of charred compounds and in their chemical composition. The resulting charred materials from the different litter, showed an important variability in the degree of carbonitation/aromatization. Unlike the biochar obtained through pyrolysis of woody sources, which contains exclusively aromatic structures, in the charred material produced in some litter, lignin, cellulose and even cellulose persist even in the high soil burnt severity. Coinciding with increases in aromatic contents, important decreases in atomic H/C and O/C ratios were recorded. However, the values found in some

  5. Carbon Sequestration and Nitrogen Mineralization in Soil Cooperated with Organic Composts and Bio-char During Corn (Zea mays) Cultivation

    Science.gov (United States)

    Shin, Joung-Du; Lee, Sun-Ill; Park, Wu-Gyun; Choi, Yong-Su; Hong, Seong-Gil; Park, Sang-Won

    2014-05-01

    Objectives of this study were to estimate the carbon sequestration and to evaluate nitrogen mineralization and nitrification in soils cooperated with organic composts and bio-char during corn cultivation. For the experiment, the soil used in this study was clay loam types, and application rates of chemical fertilizer and bio-char were recommended amount after soil test and 2 % to soil weight, respectively. The soil samples were periodically taken at every 15 day intervals during the experimental periods. The treatments were consisted of non-application, cow manure compost, pig manure compost, swine digestate from aerobic digestion system, their bio-char cooperation. For the experimental results, residual amount of inorganic carbon was ranged from 51 to 208kg 10a-1 in soil only cooperated with different organic composts. However it was estimated to be highest at 208kg 10a-1 in the application plot of pig manure compost. In addition to bio-char application, it was ranged from 187.8 to 286kg 10a-1, but was greatest accumulated at 160.3kg 10a-1 in the application plot of cow manure compost. For nitrogen mineralization and nitrification rates, it was shown that there were generally low in the soil cooperated with bio-char compared to the only application plots of different organic composts except for 71 days after sowing. Also, they were observed to be highest in the application plot of swine digestate from aerobic digestion system. For the loss of total inorganic carbon (TIC) by run-off water, it was ranged from 0.18 to 0.36 kg 10a-1 in the different treatment plots. Also, with application of bio-char, total nitrogen was estimated to be reduced at 0.42(15.1%) and 0.38(11.8%) kg 10a-1 in application plots of the pig manure compost and aerobic digestate, respectively.

  6. Char particle fragmentation and its effect on unburned carbon during pulverized coal combustion. Quarterly report, April 1--June 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.E.

    1996-08-13

    This document is the eleventh quarterly status report of work on a project concerned with the fragmentation of char particles during pulverized coal combustion that was conducted at the High Temperature Gasdynamics Laboratory at Stanford University, Stanford, California. The project is intended to satisfy, in part, PETC`s research efforts to understand the chemical and physical processes that govern coal combustion. The work is pertinent to the char oxidation phase of coal combustion and focuses on how the fragmentation of coal char particles affects overall mass loss rates and how char fragmentation phenomena influence coal conversion efficiency. The knowledge and information obtained allows the development of engineering models that can be used to predict accurately char particle temperatures and total mass loss rates during pulverized coal combustion. In particular, the work provides insight into causes of unburned carbon in the ash of coal-fired utility boilers and furnaces. The overall objectives of the project are: (i) to characterize fragmentation events as a function of combustion environment, (ii) to characterize fragmentation with respect to particle porosity and mineral loadings, (iii) to assess overall mass loss rates with respect to particle fragmentation, and (iv) to quantify the impact of fragmentation on unburned carbon in ash. The knowledge obtained during the course of this project will be used to predict accurately the overall mass loss rates of coals based on the mineral content and porosity of their chars. The work will provide a means of assessing reasons for unburned carbon in the ash of coal fired boilers and furnaces.

  7. Arsenic(V) biosorption by charred orange peel in aqueous environments.

    Science.gov (United States)

    Abid, Muhammad; Niazi, Nabeel Khan; Bibi, Irshad; Farooqi, Abida; Ok, Yong Sik; Kunhikrishnan, Anitha; Ali, Fawad; Ali, Shafaqat; Igalavithana, Avanthi Deshani; Arshad, Muhammad

    2016-01-01

    Biosorption efficiency of natural orange peel (NOP) and charred orange peel (COP) was examined for the immobilization of arsenate (As(V)) in aqueous environments using batch sorption experiments. Sorption experiments were carried out as a function of pH, time, initial As(V) concentration and biosorbent dose, using NOP and COP (pretreated with sulfuric acid). Arsenate sorption was found to be maximum at pH 6.5, with higher As(V) removal percentage (98%) by COP than NOP (68%) at 4 g L(-1) optimum biosorbent dose. Sorption isotherm data exhibited a higher As(V) sorption (60.9 mg g(-1)) for COP than NOP (32.7 mg g(-1)). Langmuir model provided the best fit to describe As(V) sorption. Fourier transform infrared spectroscopy and scanning electron microscopy combined with energy dispersive X-ray spectroscopy analyses revealed that the -OH, -COOH, and -N-H surface functional groups were involved in As(V) biosorption and the meso- to micro-porous structure of COP sequestered significantly (2-times) higher As(V) than NOP, respectively. Arsenate desorption from COP was found to be lower (10%) than NOP (26%) up to the third regeneration cycle. The results highlight that this method has a great potential to produce unique 'charred' materials from the widely available biowastes, with enhanced As(V) sorption properties.

  8. Thermoplastic behaviour and structural evolution of coke and char particles in a single particle reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir Strezov; Jianglong Yu; Guisu Liu; John A. Lucas [University of Newcastle, Mayfield, NSW (Australia). Newbolds Applied Research

    2003-07-01

    Although coking and thermal coals have quite disparate properties and applications, both coal types undergo devolatilisation in their respective utilisation processes. The resultant carbonised materials, coke and char, show significant variations in the resulting physical structure. In both cases, particles ranging from highly porous cenospheres to very dense particles are produced. Previous studies have concluded that the physical structure affects highly significant process variables such as burnout efficiency of char, ash formation during combustion and the strength of lump coke in the blast furnace. It is therefore necessary to understand the evolution of physical structure during carbonisation of coals. In the present work a direct observation of particle swelling behaviour and bubbling phenomena during pyrolysis of coking and thermal coal particles was conducted using a single particle reactor. Coking and thermal coals were thermally treated under conditions pertinent to their thermoplastic development, e.g. coking coals were subjected to low heating rates while the thermal coals under high heating rates. Bubble growth and ruptures during the plastic stage were captured using a CCD video camera equipped with a long distance microscopic lens. There were similarities in bubble formation between both thermal and coking coals such as multi-bubble and single bubble development and rupture and consequent particle shrinkage. Comparative and quantitative analysis of the thermoplastic behaviour of the coking and thermal coals are here outlined in detail. 13 refs., 8 figs., 2 tabs.

  9. Chemical and structural characterization of char development during lignocellulosic biomass pyrolysis.

    Science.gov (United States)

    Mafu, Lihle D; Neomagus, Hein W J P; Everson, Raymond C; Strydom, Christien A; Carrier, Marion; Okolo, Gregory N; Bunt, John R

    2017-11-01

    The chemical and structural changes of three lignocellulosic biomass samples during pyrolysis were investigated using both conventional and advanced characterization techniques. The use of ATR-FTIR as a characterization tool is extended by the proposal of a method to determine aromaticity, the calculation of both CH2/CH3 ratio and the degree of aromatic ring condensation ((R/C)u). With increasing temperature, the H/C and O/C ratios, XA and CH2/CH3 ratio decreased, while (R/C)u and aromaticity increased. The micropore network developed with increasing temperature, until the coalescence of pores at 1100°C, which can be linked to increasing carbon densification, extent of aromatization and/or graphitization of the biomass chars. WAXRD-CFA measurements indicated the gradual formation of nearly parallel basic structural units with increasing carbonization temperature. The char development can be considered to occur in two steps: elimination of aliphatic compounds at low temperatures, and hydrogen abstraction and aromatic ring condensation at high temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Inverse estimation of properties for charring material using a hybrid genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hee Chul; Yoon, Kyung Beom; Kim, Tae Kuk [Chung Ang University, Seoul (Korea, Republic of); Park, Won Hee; Lee, Duck Hee; Jung, Woo Sung [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2011-06-15

    Fire characteristics can be analyzed more realistically by using more accurate material properties related to the fire dynamics and one way to acquire these fire properties is to use one of the inverse property estimation techniques. In this study an optimization algorithm which is frequently applied for the inverse heat transfer problems is selected to demonstrate the procedure of obtaining fire properties of a solid charring material with relatively simple chemical structure. Thermal decomposition is occurred at the surface of the test plate by receiving the radiative energy from external heat sources and in this process the heat transfer through the test plate can be simplified by an unsteady one dimensional problem. The input parameters for the analyses are the surface temperature and mass loss rate of the char plate which are determined from the actual experiment of from the unsteady one-dimensional analysis with a given set of eight properties. The performance of hybrid genetic algorithm (HGA) is compare with a basic genetic algorithm (GA) in order to examine its performance. This comparison is carried out for the inverse property problem of estimating the fire properties related to the reaction pyrolysis of some relatively simple materials; redwood and red oak. Results show that the hybrid genetic algorithm has better performance in estimating the eight pyrolysis properties than the genetic algorithm.

  11. Modeling and evaluation of chromium remediation from water using low cost bio-char, a green adsorbent.

    Science.gov (United States)

    Mohan, Dinesh; Rajput, Shalini; Singh, Vinod K; Steele, Philip H; Pittman, Charles U

    2011-04-15

    Oak wood and oak bark chars were obtained from fast pyrolysis in an auger reactor at 400-450 °C. These chars were characterized and utilized for Cr(VI) remediation from water. Batch sorption studies were performed at different temperatures, pH values and solid to liquid ratios. Maximum chromium was removed at pH 2.0. A kinetic study yielded an optimum equilibrium time of 48 h with an adsorbent dose of 10 g/L. Sorption studies were conducted over a concentration range of 1-100mg/L. Cr(VI) removal increased with an increase in temperature (Q(Oak wood)(°): 25 °C = 3.03 mg/g; 35 °C = 4.08 mg/g; 45 °C = 4.93 mg/g and Q(Oakbark)(°): 25 °C = 4.62 mg/g; 35 °C = 7.43 mg/g; 45 °C = 7.51 mg/g). More chromium was removed with oak bark than oak wood. The char performances were evaluated using the Freundlich, Langmuir, Redlich-Peterson, Toth, Radke and Sips adsorption isotherm models. The Sips adsorption isotherm model best fits the experimental data [high regression (R(2)) coefficients]. The overall kinetic data was satisfactorily explained by a pseudo second order rate expression. Water penetrated into the char walls exposing Cr(VI) to additional adsorption sites that were not on the surfaces of dry char pores. It is remarkable that oak chars (S(BET): 1-3m(2)g(-1)) can remove similar amounts of Cr(VI) as activated carbon (S(BET): ∼ 1000 m(2)g(-1)). Thus, byproduct chars from bio-oil production might be used as inexpensive adsorbents for water purification. Char samples were successfully used for chromium remediation from contaminated surface water with dissolved interfering ions. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Modeling char conversion under suspension fired conditions in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Jacob Brix; Peter Arendt Jensen; Anker Degn Jensen [Department of Chemical and Biochemical Engineering, Lyngby (Denmark)

    2011-06-15

    The aim of this investigation has been to model combustion under suspension fired conditions in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} mixtures. Experiments used for model validation have been carried out in an electrically heated Entrained Flow Reactor (EFR) at temperatures between 1173 K and 1673 K with inlet O{sub 2} concentrations between 5 and 28 vol.%. The Coal Combustion Model, COCOMO, includes the three char morphologies: cenospheric char, network char and dense char each divided between six discrete particle sizes. Both combustion and gasification with CO{sub 2} are accounted for and reaction rates include thermal char deactivation, which was found to be important for combustion at high reactor temperatures and high O{sub 2} concentrations. COCOMO show in general good agreement with experimental char conversion profiles at conditions covering zone I-III. From the experimental profiles no effect of CO{sub 2} gasification on char conversion has been found. COCOMO does however suggest that CO{sub 2} gasification in oxy-fuel combustion at low O{sub 2} concentrations can account for as much as 70% of the overall char consumption rate during combustion in zone III. 54 refs., 20 figs., 4 tabs., 2 apps.

  13. Low-calorie bread baked with charred cellulose granules and wheat flour to eliminate toxic xanthene food dye in the alimentary canal.

    Science.gov (United States)

    Tabara, Aya; Yamane, Chihiro; Seguchi, Masaharu

    2012-01-01

    We baked low-calorie bread by mixing charred cellulose granules with wheat flour, using the charred cellulose granules to eliminate toxic xanthene food dyes contained in processed foods from the alimentary canal. The size of the charred cellulose granules played an important role in determining good breadmaking properties in respect of the bread height (mm) and specific volume (SV, cm3/g). Charred cellulose granules with a diameter above 270 μm were blended with wheat flour at 10% to obtain bread with a lower caloric content (1020 kcal/gram of bread) than the control bread (1126 kcal) made solely from wheat flour. The charred cellulose granules taken out from the bread adsorbed toxic xanthene food dyes at around pH 6.5, such that toxic food dyes taken into the alimentary canal were excreted in the feces with the non-digestible cellulose granules.

  14. Simulation of coal and char nitrogen reactions in combustion. [Final report, September 1992--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kumpaty, S.K.

    1993-10-01

    The observed rate of increase of N{sub 2}O (0.18% to 0.26% annually) is a matter of increasing concern both because N{sub 2}O is a greenhouse gas and has a major and unfavorable influence on the ozone layer (Weiss, 1981). The combustion contribution to the overall nitrous oxide budget is difficult to assess; yet the emission of N{sub 2}O from fluidized bed combustion (FBC) has been identified in the past few years as significant. It was concluded in the European workshop, 1988 that the emission level from a coal-fired fluidized bed boiler is 50--200 ppM but it is only 1--20 ppM in boilers equipped with other types of combustion devices. For this reason it is worthwhile to investigate the emissions from FBC more thoroughly. Gaseous fuels (Miller and Bowman, 1989), but the N{sub 2}O emissions under fluidized bed conditions is poorly understood. In fluidized bed combustion, N{sub 2}O can arise from homogeneous gas phase reactions involving amines and cyano species (Hiltunen et al, 1991) or it can be formed from heterogeneous reactions (eg. char oxidation). Removal of N{sub 2}O can be brought about by gas phase reactions or by catalytic or non-catalytic heterogeneous reduction on char/limestone. This work was carried out with an objective of enhancing the fundamental understanding of coal and char nitrogen reaction pathways in fluidized bed combustion environment. The formation and destruction of HCN and N{sub 2}O under variety of influential parameters were investigated. This simulation contained a nonisothermal single particle combustion in a preheated reactor and a gas phase reaction are designed to stimulate the nitrogen chemistry in a circulating fluidzied bed. The LSODE differential equation solver used for single particle combustion and the CHEMKIN package, developed by Sandia National Laboratories, was applied for gas phase reactions. This computational work was done as an exploratory research program under the solicitation of the DOE fossil energy utilization.

  15. Gasification of coal-derived chars in synthesis gas mixtures under intraparticle mass-transfer-controlled conditions

    NARCIS (Netherlands)

    Bliek, A.; Lont, J.C.; van Swaaij, Willibrordus Petrus Maria

    1986-01-01

    A model has been formulated to describe the quasi-steady-state gasification of coal-derived chars in gas mixtures where both the reactants carbon dioxide and steam, and the gasification products carbon monoxide and hydrogen are present. As such, these conditions reflect the situation found in most

  16. Are forestation, bio-char and landfilled biomass adequate offsets for the climate effects of burning fossil fuels?

    NARCIS (Netherlands)

    Reijnders, L.

    2009-01-01

    Forestation and landfilling purpose-grown biomass are not adequate offsets for the CO2 emission from burning fossil fuels. Their permanence is insufficiently guaranteed and landfilling purpose-grown biomass may even be counterproductive. As to permanence, bio-char may do better than forests or

  17. Effects of rice husks and their chars from hydrothermal carbonization on the germination rate and root length of Lepidium sativum

    Science.gov (United States)

    Kern, Jürgen; Mukhina, Irina; Dicke, Christiane; Lanza, Giacomo; Kalderis, Dimitrios

    2015-04-01

    Currently, char substrates gain a lot of interest, since they are being discussed as a component in growing media, which may become one option for the replacement of peat. Among different thermal conversion processes of biomass hydrothermal carbonization (HTC) has been found to produce chars with similar acidic pH values like peat. The question however is, if these hydrochars, which may contain toxic phenolic compounds are suitable to be introduced as a new substitute for peat in horticulture. In this study rice husk were hydrothermally carbonized at 200° C for 6 hours, yielding in hydrochars containing organic contaminants such as phenols and furfurals, which may affect plants and soil organisms. We investigated potential toxic effects on the germination rate and the root length of cress salad (Lepidium sativum) in four fractions: i) soil control, ii) raw rice husk + soil, iii) unwashed rice char + soil and iv) acetone/water washed rice char + soil. It could be shown that phenols and furfurals, which were removed from the hydrochar after washing by 80 to 96% did not affect the germination rate and the root length of the cress plants. The lowest germination rate and root length were found in the soil control, the highest in the non-washed hydrochar treatment, indicating a fertilization effect and growth stimulation of cress salad by hydrochar. If this result can be confirmed for other target and non-target organisms in future studies, a new strategy for the production of growing media may be developed.

  18. Role of charred wood, heat-shock and light in germination of postfire phrygana species from the eastern Mediterranean Basin

    Science.gov (United States)

    Keeley, Jon E.; Babr-Keeley, Melanie

    1999-01-01

    Seeds of 22 species collected from recently burned phrygana were tested for their response to fire-type cues of charred wood and heat-shock. All Cistus species were stimulated by brief heat-shock, as shown in previous studies; however, none responded to charred wood. Only one of the 22 species was stimulated by charred wood, and only in dark-inhibited seeds, and this response did not occur in the light. The lack of charred-wood-induced germination is in contrast to the substantial proportion of species with this germination response reported for mediterranean-type vegetation in California, the Cape region of South Africa, and Western Australia. Phrygana has many species with heat-shock-stimulated germination, primarily in the Fabaceae and Cistaceae. This germination cue is widespread in these two families, thus, the presence of heat-shock-stimulated germination is a result of homologous, rather than covergent, adaptations in mediterranean-climate ecosystems. Germination response to light was not randomly distributed with respect to fire-type response. Heat-shock-stimulated species were almost uniformly light neutral, in contrast to more opportunistic colonizing species with non-refractory seeds, in which half of the species responded positively or negatively to light.

  19. To debride or not to debride? That is the question: rethinking char removal in ablative CO2 laser skin resurfacing.

    Science.gov (United States)

    Niamtu, Joe

    2008-09-01

    The treatment standard for laser skin resurfacing (LSR) includes aggressively wiping away the char with moist gauze before and after each pass to prevent heat buildup and lateral tissue damage from existing char. No published study has addressed not debriding between passes with traditional higher fluence, high-density, multipass CO(2) LSR in humans. The objective was to disprove the dogma that wiping away the laser char between treatment passes is necessary. A total of 158 patients were treated over a 23-month period with multipass, nondebrided CO(2) laser resurfacing (6 J/cm(2), density 6). A small series of split-face studies were performed by debriding one side and not debriding the other side after each pass, and 89 full-face patients were treated without debriding any char between two or three passes. Histologic and photographic studies were performed in selected patients to determine the differences between debrided and nondebrided techniques. None of the nondebrided patients experienced significant complications. Operative times were shortened as was postlaser pain and erythema. Histologic analysis showed that three passes of 6 J/cm(2) with a density of 6 produces extremely similar epidermal and dermal changes regardless of debriding between passes or not. This is the first study in humans using high-energy, high-density, multipass LSR without debriding between passes. The authors have indicated no significant interest with commercial supporters.

  20. Fuel, fire and heat: an experimental approach to highlight the potential of studying ash and char remains from archaelological contexts

    NARCIS (Netherlands)

    Braadbaart, F.; Poole, I.; Huisman, H.D.J.; Os, B. van

    2012-01-01

    As in traditional societies today ancient societies probably selected different fuels to meet specific heat requirements. Char and ash, the end products of fire, are often found in abundance in archaeological contexts. These end products can provide information regarding (i) the original fuel

  1. Cow bones char as a green sorbent for fluorides removal from aqueous solutions: batch and fixed-bed studies.

    Science.gov (United States)

    Nigri, Elbert M; Cechinel, Maria Alice P; Mayer, Diego A; Mazur, Luciana P; Loureiro, José M; Rocha, Sônia D F; Vilar, Vítor J P

    2017-01-01

    Cow bone char was investigated as sorbent for the defluoridation of aqueous solutions. The cow bone char was characterized in terms of its morphology, chemical composition, and functional groups present on the bone char surface using different analytical techniques: SEM, EDS, N2-BET method, and FTIR. Batch equilibrium studies were performed for the bone chars prepared using different procedures. The highest sorption capacities for fluoride were obtained for the acid washed (q = 6.2 ± 0.5 mg/g) and Al-doped (q = 6.4 ± 0.3 mg/g) bone chars. Langmuir and Freundlich models fitted well the equilibrium sorption data. Fluoride removal rate in batch system is fast in the first 5 h, decreasing after this time until achieving equilibrium due to pore diffusion. The presence of carbonate and bicarbonate ions in the aqueous solution contributes to a decrease of the fluoride sorption capacity of the bone char by 79 and 31 %, respectively. Regeneration of the F-loaded bone char using 0.5 M NaOH solution leads to a sorption capacity for fluoride of 3.1 mg/g in the second loading cycle. Fluoride breakthrough curve obtained in a fixed-bed column presents an asymmetrical S-shaped form, with a slow approach of C/C 0 → 1.0 due to pore diffusion phenomena. Considering the guideline value for drinking water of 1.5 mg F(-)/L, as recommended by World Health Organization, the service cycle for fluoride removal was of 71.0 h ([F(-)]feed ∼ 9 mg/L; flow rate = 1 mL/min; m sorbent = 12.6 g). A mass transfer model considering the pore diffusion was able to satisfactorily describe the experimental data obtained in batch and continuous systems.

  2. Developing (Quantitative Structure Property Relationships QSPR Techniques to Predict the Char Formation of Polybenzoxazines

    Directory of Open Access Journals (Sweden)

    Maryam Sairi

    2016-04-01

    Full Text Available This study uses the Molecular Operating Environment software (MOE to generate models to calculate the char yield of polybenzoxazines (PBz. A series of benzoxazine (Bz monomers were constructed to which a variety of parameters relating to the structure (e.g., water accessible surface, negative van der Waals surface area and hydrophobic volume, etc. were obtained and a quantitative structure property relationships (QSPR model was generated. The model was used to generate data for new Bz monomers with desired properties and a comparison was made of predictions based on the QSPR model with the experimental data. This study shows the quality of predictive models and confirms how useful computational screening is prior to synthesis.

  3. Metabolomics Approach To Evaluate a Baltic Sea Sourced Diet for Cultured Arctic Char (Salvelinus alpinus L.).

    Science.gov (United States)

    Cheng, Ken; Müllner, Elisabeth; Moazzami, Ali A; Carlberg, Hanna; Brännäs, Eva; Pickova, Jana

    2017-06-21

    Aqua feeds traditionally rely on fishmeal as a protein source, which is costly and unsustainable. A new feed was formulated in the study with Baltic Sea sourced decontaminated fishmeal, Mytilus edulis and Saccharomyces cerevisiae, and given to Arctic char (Salvelinus alpinus) for ten months. The diet-induced changes on metabolic profile in fish plasma, liver, and muscle were studied relative to a fishmeal-based standard diet by using a (1)H NMR-based metabolomics approach. Fish fed the test diet had higher content of betaine and lower levels of trimethylamine-N-oxide and aromatic amino acids in plasma or tissues, which were mainly caused by the diet. The metabolomics results are useful to understand the mechanism of lower body mass, smaller Fulton's condition factor, and a tendency of less lipid content observed in fish fed the test diet. Thus, modifications on the dietary levels of these compounds in the feed are needed to achieve better growth performance.

  4. Towards user-friendly spelling with an auditory brain-computer interface: the CharStreamer paradigm.

    Directory of Open Access Journals (Sweden)

    Johannes Höhne

    Full Text Available Realizing the decoding of brain signals into control commands, brain-computer interfaces (BCI aim to establish an alternative communication pathway for locked-in patients. In contrast to most visual BCI approaches which use event-related potentials (ERP of the electroencephalogram, auditory BCI systems are challenged with ERP responses, which are less class-discriminant between attended and unattended stimuli. Furthermore, these auditory approaches have more complex interfaces which imposes a substantial workload on their users. Aiming for a maximally user-friendly spelling interface, this study introduces a novel auditory paradigm: "CharStreamer". The speller can be used with an instruction as simple as "please attend to what you want to spell". The stimuli of CharStreamer comprise 30 spoken sounds of letters and actions. As each of them is represented by the sound of itself and not by an artificial substitute, it can be selected in a one-step procedure. The mental mapping effort (sound stimuli to actions is thus minimized. Usability is further accounted for by an alphabetical stimulus presentation: contrary to random presentation orders, the user can foresee the presentation time of the target letter sound. Healthy, normal hearing users (n = 10 of the CharStreamer paradigm displayed ERP responses that systematically differed between target and non-target sounds. Class-discriminant features, however, varied individually from the typical N1-P2 complex and P3 ERP components found in control conditions with random sequences. To fully exploit the sequential presentation structure of CharStreamer, novel data analysis approaches and classification methods were introduced. The results of online spelling tests showed that a competitive spelling speed can be achieved with CharStreamer. With respect to user rating, it clearly outperforms a control setup with random presentation sequences.

  5. Towards User-Friendly Spelling with an Auditory Brain-Computer Interface: The CharStreamer Paradigm

    Science.gov (United States)

    Höhne, Johannes; Tangermann, Michael

    2014-01-01

    Realizing the decoding of brain signals into control commands, brain-computer interfaces (BCI) aim to establish an alternative communication pathway for locked-in patients. In contrast to most visual BCI approaches which use event-related potentials (ERP) of the electroencephalogram, auditory BCI systems are challenged with ERP responses, which are less class-discriminant between attended and unattended stimuli. Furthermore, these auditory approaches have more complex interfaces which imposes a substantial workload on their users. Aiming for a maximally user-friendly spelling interface, this study introduces a novel auditory paradigm: “CharStreamer”. The speller can be used with an instruction as simple as “please attend to what you want to spell”. The stimuli of CharStreamer comprise 30 spoken sounds of letters and actions. As each of them is represented by the sound of itself and not by an artificial substitute, it can be selected in a one-step procedure. The mental mapping effort (sound stimuli to actions) is thus minimized. Usability is further accounted for by an alphabetical stimulus presentation: contrary to random presentation orders, the user can foresee the presentation time of the target letter sound. Healthy, normal hearing users (n = 10) of the CharStreamer paradigm displayed ERP responses that systematically differed between target and non-target sounds. Class-discriminant features, however, varied individually from the typical N1-P2 complex and P3 ERP components found in control conditions with random sequences. To fully exploit the sequential presentation structure of CharStreamer, novel data analysis approaches and classification methods were introduced. The results of online spelling tests showed that a competitive spelling speed can be achieved with CharStreamer. With respect to user rating, it clearly outperforms a control setup with random presentation sequences. PMID:24886978

  6. Developing a food web-based transfer factor of radiocesium for fish, whitespotted char (Salvelinus leucomaenis) in headwater streams.

    Science.gov (United States)

    Haque, Md Enamul; Gomi, Takashi; Sakai, Masaru; Negishi, Junjiro N

    2017-06-01

    We developed a food web-based transfer factor (TFweb) to study contaminant movements from multiple prey items to a predator based on the dietary contributions of prey items with their respective contamination levels. TFweb was used to evaluate the transfer of 137Cs into whitespotted char (Salvelinus leucomaenis) from the trophic structure of a stream-riparian ecosystem in headwater streams draining a Japanese cedar forest. We also examined the applicability of this method by comparing sites with different contamination levels but similar surrounding environments in Fukushima and Gunma. All samples were collected from August 2012 to May 2013. The dietary contributions from both aquatic and terrestrial prey items to whitespotted char were analyzed using stable carbon and nitrogen isotope ratios. 137Cs activity concentrations in char ranged from 704 to 6082 Bq kg-1-dry in Fukushima and from 193 to 618 Bq kg-1-dry in Gunma. Dominant prey taxa such as mayflies (Ephemera japonica), spider crickets (Rhaphidosphoridae gen. spp.), and freshwater crabs (Geothelphusa dehaani), each of them accounted for 3-12% of the fish diet, based on lower and upper estimates, respectively. TFweb ranged from 1.12 to 3.79 in Fukushima and from 1.30 to 4.30 in Gunma, which suggested bioaccumulation from prey items to predator. Widely used ecological parameters TFs by media-char and TTF by single prey-char showed high variability with both dilution and accumulation. TFweb is applicable for 137Cs transfer in predator-prey systems with complex food web structures of stream-riparian ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Physico-chemical properties and gasification reactivity of co-pyrolysis char from different rank of coal blended with lignocellulosic biomass: Effects of the cellulose.

    Science.gov (United States)

    Wu, Zhiqiang; Wang, Shuzhong; Luo, Zhengyuan; Chen, Lin; Meng, Haiyu; Zhao, Jun

    2017-07-01

    In this paper, the influence of cellulose on the physicochemical properties and the gasification reactivity of co-pyrolysis char was investigated. A specific surface area analyzer and an X-ray diffraction system were used to characterize the pore structure and the micro-crystalline structure of char. Fractal theory and deconvolution method were applied to quantitatively investigate the influence of cellulose on the structure of co-pyrolysis char. The results indicate that the improvements in the pore structure due to the presence of cellulose are more pronounced in the case of anthracite char with respect to bituminous char. Cellulose promotes the ordering of micro-scale structure and the uniformity of both anthracite and bituminous char, while the negative synergetic effect was observed during gasification of co-pyrolysis char. The exponential relationships between fractal dimension and specific surface area were determined, along with the relations between the gasification reactivity index and the microcrystalline structure parameter. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. How do the poor handle money? What do the financial diaries of char dwellers tell us about financial inclusion?

    Directory of Open Access Journals (Sweden)

    Kuntala Lahiri-Dutt

    2013-05-01

    Full Text Available Derived from livelihoods surveys and ethnographic material about people living on the chars, or river islands, in deltaic lower Bengal, this paper illustrates the complex, diverse and ingenious ways that the poor manage money. These islands constitute some of the most vulnerable housing locations of some of the poorest communities; state services and facilities do not reach the chars because they are not listed as land in revenue records. It demonstrates that the poor live in a diverse economy where community spirit, family assistance and trust play roles equally important to markets. In doing so, it puts forth a grounded-in-the-field, evidence-based, critique of the slogan ‘financial inclusion’ that has gained prominence in recent years.

  9. Pyrolysis-GC/MS of charred purified condensed tannin: towards identification of tannin-derived black carbon in environmental samples

    Science.gov (United States)

    Kaal, Joeri; Nierop, Klaas G. J.; Kraal, Peter; Preston, Caroline M.

    2010-05-01

    Tannins account for a significant proportion of plant biomass and are therefore a possible source of Black C in the charred remains from wildfires. Nonetheless, in contrast with other major biocomponents such as lignin and cellulose, the thermal degradation of tannins has not been investigated in laboratory charring experiments. We used pyrolysis-GC/MS to investigate the effects of furnace charring (30 min at fixed temperatures up to 600 °C under limited oxygen supply) on the degradation of pure condensed tannin (CT) isolated from Corsican pine (Pinus nigra) needles. The experiments showed a rapid loss (at 300 °C and higher) of the pyrogallol moieties of the B-ring of prodelphinidin-type CT, due to dehydroxylation. The relative abundance of catechols (from procyanidin-type CT) decreased at 350 °C and higher temperatures. This led to the formation of phenols that were strongly enriched between 300 and 400 °C. At higher temperatures, further dehydroxylation caused a decline in contributions of phenols producing a series of monocyclic aromatics ((alkyl)benzenes) and condensation of aromatics produced polycyclic aromatic hydrocarbons (PAHs), i.e. the typical pyrolysis fingerprint of strongly charred biomass. We conclude that (i) the thermal degradation of CT can be successfully monitored by pyrolysis-GC/MS, (ii) thermal degradation of CT is characterized by dehydroxylation of phenolic groups and condensation of aromatics that increase with temperature and (iii) CT-derived Black C may be recognized by catechol enrichments at low temperatures and possibly (relative) abundance of phenol and biphenyl at higher levels of thermal breakdown. Applying the same method to natural charcoal from gorse bushfires indicated that pyrolysis-GC/MS fingerprinting may allow for tannin identification in environmental Black C samples.

  10. Nutritional Status of under 5 Children belonging to Tribal Population Living in Riverine (Char) Areas of Dibrugarh District, Assam.

    Science.gov (United States)

    Islam, Safikul; Mahanta, Tulika Goswami; Sarma, Ratna; Hiranya, Saikia

    2014-07-01

    Assam's main lifeline, the Brahmaputra river, braided nature created numerous sand bars and islands known as chars/sapories. They are home to more than 3 million people. Over 90% of the cultivated land on the river islands is flood-prone; the flood leaves the islands completely separated from mainland, preventing access to health infrastructure and services. To assess the nutritional status of under 5 children residing in the char areas of Dibrugarh district and to identify the factors influencing their nutritional status. A community-based cross-sectional study conducted in the riverine areas of Dibrugarh district of Assam. Nutritional status was assessed using anthropometry. Undernutrition was classified using World Health Organization (WHO) recommended Z- score system. Data collection was done by house to house visit of all chars using proportionate allocation. Rates, ratios, proportions, and chi-square test. Overall prevalence of underweight, stunting, and wasting was 29%, 30.4%, and 21.6%, respectively. Prevalence of underweight and stunting was less than the prevalence of underweight (36.4%) and stunting (46.5%) in Assam, but the prevalence of wasting was more than that of Assam (13.7%) as observed in National Family Health Survey-3. Significant association was observed between the prevalence of undernutrition and socioeconomic status, literacy status of parents, infant, and young child feeding practices and size of the family (P < 0.05). Special focus is needed for nutritional improvement of under 5 living in char areas to prevent preventable morbidities and to achieve optimum development.

  11. Nutritional status of under 5 children belonging to tribal population living in riverine (Char areas of Dibrugarh district, Assam

    Directory of Open Access Journals (Sweden)

    Safikul Islam

    2014-01-01

    Full Text Available Context: Assam′s main lifeline, the Brahmaputra river, braided nature created numerous sand bars and islands known as chars/sapories. They are home to more than 3 million people. Over 90% of the cultivated land on the river islands is flood-prone; the flood leaves the islands completely separated from mainland, preventing access to health infrastructure and services. Aims: To assess the nutritional status of under 5 children residing in the char areas of Dibrugarh district and to identify the factors influencing their nutritional status. Settings and Design: A community-based cross-sectional study conducted in the riverine areas of Dibrugarh district of Assam. Materials and Methods: Nutritional status was assessed using anthropometry. Undernutrition was classified using World Health Organization (WHO recommended Z- score system. Data collection was done by house to house visit of all chars using proportionate allocation. Statistical Analysis Used: Rates, ratios, proportions, and chi-square test. Results: Overall prevalence of underweight, stunting, and wasting was 29%, 30.4%, and 21.6%, respectively. Prevalence of underweight and stunting was less than the prevalence of underweight (36.4% and stunting (46.5% in Assam, but the prevalence of wasting was more than that of Assam (13.7% as observed in National Family Health Survey-3. Significant association was observed between the prevalence of undernutrition and socioeconomic status, literacy status of parents, infant, and young child feeding practices and size of the family (P < 0.05. Conclusions: Special focus is needed for nutritional improvement of under 5 living in char areas to prevent preventable morbidities and to achieve optimum development.

  12. Synergistic effect of a novel triazine charring agent and ammonium polyphosphate on the flame retardant properties of halogen-free flame retardant polypropylene composites

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Caimin; Liang, Minyi; Jiang, Jiali; Huang, Jianguang, E-mail: hjguang@139.com; Liu, Hongbo, E-mail: 962651061@qq.com

    2016-03-20

    Highlights: • A novel triazine charring agent was prepared, and the synergistic effect has been studied between APP and novel charring agent. • The novel IFR system presents excellent flame retardant properties and smoke suppression ability. • The flame retardant mechanism shows that it has high graphitization degree and good shield properties of the char layer. - Abstract: A novel triazine charring agent poly(4,6-dichloro-N-butyl-1,3,5-triazin-2-amine-ethylenediamine) (CNCD-DA) was synthesized, which had good thermal stability and char-forming ability. The synergistic effects between ammonium polyphosphate (APP) and CNCD-DA on flame retardant properties and mechanism of polypropylene (PP) were investigated by the limited oxygen index (LOI), vertical burning test (UL-94), cone calorimeter test (CCT), scanning electron microscopy (SEM), laser Raman spectroscopy analysis (LRS), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results illustrated when the mass ratio of APP to CNCD-DA was 3:1 with 30% loading, the intumescent flame retardant (IFR) showed the best synergistic effect with LOI value reaching 36.5%, and the IFR could greatly suppress the generation of the flame and smoke during combustion. The results from SEM, TGA, LRS and FTIR indicated that during the combustion IFR could form a continuous and intumescent char containing P−O−P and P−O−C crosslinking structures and polyaromatic structures, thus effectively retard the combustion of PP.

  13. Sorption of apolar and polar organic contaminants by waste tire rubber and its chars in single- and bi-solute systems

    Energy Technology Data Exchange (ETDEWEB)

    Lian Fei; Huang Fang; Chen Wei [College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Nankai University, Tianjin 300071 (China); Xing Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States); Zhu Lingyan, E-mail: zhuly@nankai.edu.cn [College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Nankai University, Tianjin 300071 (China)

    2011-04-15

    Single- and bi-solute sorption of organic compounds [1,3-dichlorbenzene (DCB), 1,3-dinitrobenzene (DNB) and 2,4-dichlorophenol (DCP)] on ground tire rubber and its chars was studied. The chars were prepared by pyrolyzing tire rubber at different temperatures (200-800 deg. C). Their surface area, aromaticity and hydrophobicity increase greatly with pyrolytic temperature, and the polymeric phase is partly converted into a condensed phase. The sorption of DNB and DCP increases with pyrolytic temperature and is characterized by a transition from a partition dominant to an adsorption dominant process. However, the sorption of DCB linearly decreases with the pyrolytic temperature. The enhanced adsorption of DNB and DCP on carbonized phase is primarily attributed to nonhydrophobic interactions such as {pi}-{pi} electron-donor-acceptor interactions and/or H bonding. The higher partition of DCB to polymeric phase is attributed to its high hydrophobicity. Competitive sorption between DCB and DCP on the tire chars is highly dependent on dissociation of the latter. - Research highlights: > Tire chars consist of dual sorptive domains, i.e., partition and adsorption. > High hydrophobicity of apolar organic contaminant promotes its partition into polymeric phase. > Polar aromatic contaminants show high adsorption on carbonized phase with specific interactions. > Dissociation of ionzable organic chemical heavily influences its sorption on tire chars. - The partition and adsorption of organic contaminants on waste tire chars are highly dependent on the hydrophobicity, polarity and dissociation of solutes.

  14. Model for biomass char combustion in the riser of a dual fluidized bed gasification unit: Part II - model validation and parameter variation

    Energy Technology Data Exchange (ETDEWEB)

    Kaushal, Priyanka; Proell, Tobias; Hofbauer, Hermann [Vienna University of Technology, Institute of Chemical Engineering, Getreidemarkt 9/166, A-1060, Vienna (Austria)

    2008-07-15

    The two-phase combustion model for biomass char combustion in a riser of a dual fluidized bed gasification unit that has been presented in part I is validated using the data obtained from the 8 MWth dual fluidized bed reactor at Guessing/Austria. The model is capable of calculating the average temperatures in all zones, the gas phase composition, solid hold up, char feed rates and air ratio. The model predictions for the temperature profile along the riser and for the exiting gas composition are in good agreement with the measured values. The simulation results show that the residual char from the gasifier is only partly converted in the riser for char particles larger than 0.6 mm. Un-combusted char is circulated back into the gasification reactor. Parameter variations show that the exact location where additional liquid fuels are introduced in the middle zone of the riser does not affect the global behaviour of the combustion reactor. Based on the simulation results it is proposed that external supply of char (additional) may be a very effective method for reducing producer gas recycling to the riser, which is currently necessary to obtain the desired gasification temperatures. (author)

  15. A comparative study of aerobically digested and undigested sludge in preparation of magnetic chars and their application in 1-diazo-2-naphthol-4-sulfonic acid adsorption.

    Science.gov (United States)

    Gu, Lin; Zhu, Nanwen; Zhang, Daofang; Lou, Ziyang; Yuan, Haiping; Zhou, Pin

    2013-05-01

    In this work, two types of sewage-sludges, aerobically digested and undigested sewage sludge, were used as precursors in the preparation of chars with magnetic property. The two solids were characterized to establish their textural and chemical properties. Due to different elemental composition, chars from the digested sludge were found to contain zeolite-like minerals such as NaP1 zeolite, which enables its abilities of anion exchange, while chars from undigested sewage sludge exhibited a well-degreed graphite structure. 1-Diazo-2-naphthol-4-sulfonic acid (1,2,4-Acid) was used as a model pollutant to investigate its adsorption on prepared chars. The adsorption kinetics of 1,2,4-Acid onto both chars followed pseudo-second-order kinetics. The simulated Langmuir-Freundlich model illustrated that the equilibrium adsorption amount of 1,2,4-Acid was 102.8 and 105.3mg/g, respectively, at 303 K. The adsorption amount declined on digested chars, whereas kept stable on the other in the presence of sodium chloride, suggesting the diversity in adsorption behavior. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Radiocarbon dating of charred human bone remains preserved in urns excavated from medieval Buddhist cemetery in Japan

    Science.gov (United States)

    Nakamura, Toshio; Sagawa, Shinichi; Yamada, Tetsuya; Kanehara, Masaaki; Tsuchimoto, Norio; Minami, Masayo; Omori, Takayuki; Okuno, Mitsuru; Ohta, Tomoko

    2010-04-01

    For a preliminary test of 14C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS 14C dating, carbon and nitrogen contents, δ13C and δ15N values of the fragments. All 14C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some 14C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older 14C ages, most probably as the result of old wood effect.

  17. Pilot-scale studies of NOx reduction by activated high-sodium lignite chars: A demonstration of the CARBONOX process

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, H.; Benson, S.A.; Fan, L.S.; Laumb, J.D.; Olson, E.S.; Crocker, C.R.; Sharma, R.K.; Knutson, R.Z.; Rokanuzzaman, A.S.M.; Tibbets, J.E. [Ohio State University, Columbus, OH (US). Dept. of Chemical Engineering

    2004-09-01

    Pilot-scale experiments were carried out to quantify the extent of NOx reduction attained by activated lignite chars on simulated and lignite-coal-combustion derived flue gas. Lignite chars, obtained by devolatilizing high-sodium lignite coal in pure nitrogen, were activated by their reaction with a gas mixture consisting of steam and CO{sub 2} in nitrogen at 700-750{degree}C to yield a nitrogen BET surface area of 200-400 m{sup 2}/g. The effect of gaseous components such as N{sub 2}, CO{sub 2}, SO{sub 2}, and moisture on the extent of NOx reduction was qualitatively examined. NOx reduction exceeded 99% on simulated flue gas at 525-600{degree}C. The presence of SO{sub 2}, even at a concentration of 3600 ppm, did not have any detrimental effect on the extent of NOx reduction. Sodium-enhanced char attained {gt} 98% NOx reduction on actual flue gas at a relatively lower temperature of 480-560{degree}C.

  18. Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

    Science.gov (United States)

    Kılıç, Murat; Kırbıyık, Çisem; Çepelioğullar, Özge; Pütün, Ayşe E.

    2013-10-01

    Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

  19. Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kılıç, Murat [Department of Chemical Engineering, Faculty of Engineering, Anadolu University, 26555 Eskişehir (Turkey); Kırbıyık, Çisem [Department of Chemical Engineering, Faculty of Engineering, Selçuk University, 42075 Konya (Turkey); Çepelioğullar, Özge [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University, 34469 Istanbul (Turkey); Pütün, Ayşe E., E-mail: aeputun@anadolu.edu.tr [Department of Chemical Engineering, Faculty of Engineering, Anadolu University, 26555 Eskişehir (Turkey)

    2013-10-15

    Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

  20. Radiocarbon dating of charred human bone remains preserved in urns excavated from medieval Buddhist cemetery in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio, E-mail: nakamura@nendai.nagoya-u.ac.j [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Sagawa, Shinichi; Yamada, Tetsuya [Gangoji Institute for Research of Cultural Properties, Nakain, Nara 630-8392 (Japan); Kanehara, Masaaki [School of Science Education, Nara University of Education, Takabatake, Nara 630-8528 (Japan); Tsuchimoto, Norio [Ichinomiya City Museum, Yamato, Ichinomiya 491-0922 (Japan); Minami, Masayo [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Omori, Takayuki [Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Okuno, Mitsuru [Faculty of Science, Fukuoka University, Jonan, Fukuoka 814-0180 (Japan); Ohta, Tomoko [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan)

    2010-04-15

    For a preliminary test of {sup 14}C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS {sup 14}C dating, carbon and nitrogen contents, delta{sup 13}C and delta{sup 15}N values of the fragments. All {sup 14}C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some {sup 14}C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older {sup 14}C ages, most probably as the result of old wood effect.

  1. Synthesis and structural features of resorcinol⿿formaldehyde resin chars containing nickel nanoparticles

    Science.gov (United States)

    Galaburda, M. V.; Bogatyrov, V. M.; Skubiszewska-ZiĿba, J.; Oranska, O. I.; Sternik, D.; Gun⿿ko, V. M.

    2016-01-01

    A series of meso- and microporous carbons containing magnetic Ni nanoparticles (Ni/C) with a variety of Ni loadings were synthesized by a simple one-pot procedure through carbonization of resorcinol⿿formaldehyde polymers containing various amounts of nickel(II) acetate. Such composite materials were characterized by N2 sorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). The XRD patterns reveal peaks corresponding to face centered cubic nickel with the average size of crystallites of 17⿿18 nm. SEM and TEM results reveal that the formation of the nanoparticles took place mainly in the carbon spheres (1⿿2 μm in size) and on the outer surface as well. The as-prepared composites are characterized by a core⿿shell structure with well-crystallized graphitic shells about 8⿿15 nm in thickness. The Raman spectra show that Ni content influences the structure of the carbon. It was also shown that the morphology (particle shape and sizes) and porosity (pore volume and pore size distribution) of the chars are strongly dependent on water and nickel contents in the blends. One of the applications of Ni/C was demonstrated as a magnetically separable adsorbent.

  2. Supercritical water gasification of Eucalyptus grandis and related pyrolysis char: Effect of feedstock composition.

    Science.gov (United States)

    Louw, Jeanne; Schwarz, Cara E; Burger, Andries J

    2016-09-01

    Eucalyptus grandis (E. grandis) wood and char products derived from pyrolysis of E. grandis wood, were gasified in supercritical water at 450°C - with and without the use of a homogeneous (K2CO3) and heterogeneous (Ni/Al2O3-SiO2) catalyst. Gas yields and gasification efficiencies were measured experimentally and compared to calculated thermodynamic equilibrium values, specifically considering the effects of the O/C ratio and volatile matter content of the feed material. Thermodynamically, feed material with lower O/C ratios (0.22) typically resulted in higher CH4 yields (30mol/kgfeed,dry) and gasification efficiencies (188%). However, experimentally, feed material with lower O/C ratios and lower volatile matter resulted in the lowest CH4 yields and gasification efficiencies. Furthermore, a linear relationship between the carbon efficiency (CE) and both the volatile matter content and O/C ratio of the feed material was found to hold true in both catalytic and non-catalytic experiments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Estimation of surface heat flux for ablation and charring of thermal protection material

    Science.gov (United States)

    Qian, Wei-qi; He, Kai-feng; Zhou, Yu

    2016-07-01

    Ablation of the thermal protection material of the reentry hypersonic flight vehicle is a complex physical and chemical process. To estimate the surface heat flux from internal temperature measurement is much more complex than the conventional inverse heat conduction problem case. In the paper, by utilizing a two-layer pyrogeneration-plane ablation model to model the ablation and charring of the material, modifying the finite control volume method to suit for the numerical simulation of the heat conduction equation with variable-geometry, the CGM along with the associated adjoint problem is developed to estimate the surface heat flux. This estimation method is verified with a numerical example at first, the results show that the estimation method is feasible and robust. The larger is the measurement noise, the greater is the deviation of the estimated result from the exact value, and the measurement noise of ablated surface position has a significant and more direct influence on the estimated result of surface heat flux. Furthermore, the estimation method is used to analyze the experimental data of ablation of blunt Carbon-phenolic material Narmco4028 in an arc-heater. It is shown that the estimated surface heat flux agrees with the heating power value of the arc-heater, and the estimation method is basically effective and potential to treat the engineering heat conduction problem with ablation.

  4. Effect of sewage sledge and their bio-char on some soil qualities

    Science.gov (United States)

    Fathi, Hamed; Movahedi Naeini, Seyed Alireza; Mirzanejad, Mojan

    2015-04-01

    Bio char (BC) application as a soil amendment has achieved much interest and has been found that considerably improves soil nutrient status and crop yields on poor soils. However, information on the effect of BC on illitic soils in temperate climates is still insufficient. The primary objective in this study was to assess the influence of biochar on the soil physical properties, nutrient status and plant production. The result may also provide a reference for the use of biochars as a solution in agricultural waste management when sludge with considerable load of pathogens are involved. Soybean was already grown one year and will be repeated one more year with same treatments. The investigated soil properties included soil water content and mechanical resistance, pH, electrical conductivity (EC), calcium- acetate-lactate (CAL)-extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show soil water content, potassium uptake and plant yield were increased. Heating sludge removed all pathogens and soybean yield was increased by 6%.

  5. Tetracycline adsorption onto activated carbons produced by KOH activation of tyre pyrolysis char.

    Science.gov (United States)

    Acosta, R; Fierro, V; Martinez de Yuso, A; Nabarlatz, D; Celzard, A

    2016-04-01

    Tyre pyrolysis char (TPC), produced when manufacturing pyrolysis oil from waste tyre, was used as raw material to prepare activated carbons (ACs) by KOH activation. KOH to TPC weight ratios (W) between 0.5 and 6, and activation temperatures from 600 to 800 °C, were used. An increase in W resulted in a more efficient development of surface area, microporosity and mesoporosity. Thus, ACs derived from TPC (TPC-ACs) with specific surface areas up to 814 m(2) g(-1) were obtained. TPC, TPC-ACs and a commercial AC (CAC) were tested for removing Tetracycline (TC) in aqueous phase, and systematic adsorption studies, including equilibrium, kinetics and thermodynamic aspects, were performed. Kinetics was well described by the pseudo-first order model for TPC, and by a pseudo second-order kinetic model for ACs. TC adsorption equilibrium data were also fitted by different isotherm models: Langmuir, Freundlich, Sips, Dubinin-Radushkevich, Dubinin-Astokov, Temkin, Redlich-Peterson, Radke-Prausnitz and Toth. The thermodynamic study confirmed that TC adsorption onto TPC-ACs is a spontaneous process. TC adsorption data obtained in the present study were compared with those reported in the literature, and differences were explained in terms of textural properties and surface functionalities. TPC-ACs had similar performances to those of commercial ACs, and might significantly improve the economic balance of the production of pyrolysis oil from waste tyres. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Synergistic effect on co-gasification reactivity of biomass-petroleum coke blended char.

    Science.gov (United States)

    Wei, Juntao; Guo, Qinghua; Gong, Yan; Ding, Lu; Yu, Guangsuo

    2017-06-01

    In this work, effects of gasification temperature (900°C-1100°C) and blended ratio (3:1, 1:1, 1:3) on reactivity of petroleum coke and biomass co-gasification were studied in TGA. Quantification analysis of active AAEM transformation and in situ investigation of morphological structure variations in gasification were conducted respectively using inductively coupled plasma optical emission spectrometer and heating stage microscope to explore synergistic effect on co-gasification reactivity. The results indicated that char gasification reactivity was enhanced with increasing biomass proportion and gasification temperature. Synergistic effect on co-gasification reactivity was presented after complete generation of biomass ash, and gradually weakened with increasing temperature from 1000°C to 1100°C after reaching the most significant value at 1000°C. This phenomenon was well related with the appearance of molten biomass ash rich in glassy state potassium and the weakest inhibition effect on active potassium transformation during co-gasification at the temperature higher than 1000°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Kinetic models comparison for steam gasification of coal/biomass blend chars.

    Science.gov (United States)

    Xu, Chaofen; Hu, Song; Xiang, Jun; Yang, Haiping; Sun, Lushi; Su, Sheng; Wang, Baowen; Chen, Qindong; He, Limo

    2014-11-01

    The non-isothermal thermogravimetric method (TGA) was applied to different chars produced from lignite (LN), sawdust (SD) and their blends at the different mass ratios in order to investigate their thermal reactivity under steam atmosphere. Through TGA analysis, it was determined that the most prominent interaction between sawdust and lignite occurred at the mass ratio of sawdust/lignite as 1:4, but with further dose of more sawdust into its blends with lignite, the positive interaction deteriorated due to the agglomeration and deactivation of the alkali mineral involved in sawdust at high steam gasification temperature. Through systematic comparison, it could be observed that the random pore model was the most suitable among the three gas-solid reaction models adopted in this research. Finally, rational kinetic parameters were reached from these gas-solid reaction models, which provided a basis for design and operation of the realistic system of co-gasification of lignite and sawdust in this research. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Use of postmortem computed tomography to reveal an intraoral gunshot injuries in a charred body.

    Science.gov (United States)

    Sano, Rie; Hirawasa, Satoshi; Kobayashi, Susumu; Shimada, Takehiro; Awata, Sachiko; Takei, Hiroyuki; Otake, Hidenori; Takahashi, Keiko; Takahashi, Youichiro; Kominato, Yoshihiko

    2011-11-01

    A 53-year-old man was found dead after a fire at his residence had been extinguished. Although a pistol was recovered beside the body, external examination was unable to indicate any gunshot wound because of severe charring of the body. Postmortem computed tomography (CT) scan performed prior to autopsy suggested an entrance gunshot wound in the posterior pharynx with loss of soft tissue and an internal bullet path through the right anterior and posterior parts of the occipital bone. Autopsy revealed an entrance gunshot wound with hemorrhage in the soft tissue of the posterior pharynx, massive contusion of the right occipital lobe, and subarachnoid hemorrhage in the right temporal lobe, both occipital lobes and the superior surface of the left cerebellar hemisphere, thus being consistent with the findings of postmortem CT. A carboxyhemoglobin concentration of 5% in blood from the cadaver was consistent with the lack of soot deposition from the larynx to the bronchus. These observations confirmed that death had been caused by an intraoral gunshot resulting in severe brain damage, before the body had been burned. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Impact of pretreatment on defluoridation of drinking water by bone char adsorption

    Directory of Open Access Journals (Sweden)

    Adam Teusner

    2016-03-01

    Full Text Available Fluoride concentrations in drinking water in excess of 1.5 mg L-1 are unsafe for human consumption. To reduce excess fluoride intake, developing countries must use low-cost, point-of-use defluoridation techniques. Although previous work has extensively assessed defluoridation using bone char (BC, most of the advanced studies have been based on the use of fluoridated distilled water as a feed solution. In the present study, BC columns were challenged with a range of model solutions, mimicking various pretreatment options. As a result, the relative impact of dissolved organic carbon (DOC and suspended solids (SS on the performance of BC filters was assessed. In addition, the performance of a gravity-driven, hollow fibre ultrafiltration (UF module was examined with regards to the potential for use as a pretreatment option. SS were observed to severely clog the columns and cause the complete cessation of flow. The subsequent removal of SS by UF improved the general filter performance as well as increasing the BC lifetime by 50 %. The UF module achieved a reduction in DOC of 34 ± 6 %, resulting in an additional 30 % increase in the lifetime of the BC column.

  10. Adsorption of SO2 on bituminous coal char and activated carbon fiber

    Science.gov (United States)

    DeBarr, Joseph A.; Lizzio, Anthony A.; Daley, Michael A.

    1997-01-01

    The SO2 adsorption behaviors of activated carbons produced from Illinois coal and of commercially prepared activated carbon fibers (ACFs) were compared. There was no relation between surface area of coal-based carbons and SO2 adsorption, whereas adsorption of SO2 on the series of ACFs was inversely proportional to N2 BET surface area. Higher surface area ACFs had wider pores and adsorbed less SO2; thus, pore size distribution is thought to play a significant role in SO2 adsorption for these materials. Oxidation with HNO3 and/or H2SO4, followed by heat treatment at 700−925°C to remove carbon−oxygen complexes, resulted in increased SO2 adsorption for both coal chars and ACFs. This behavior was explained by an increase in the available number of free sites, previously occupied by oxygen and now available for SO2 adsorption. The use of nitrogen-containing functional groups on ACFs of proper pore size shows promise for further increasing SO2 adsorption capacities. Knowledge of the relationship among the number of free sites, pore size, and surface chemistry on corresponding SO2 adsorption should lead to the development of more efficient adsorbents prepared from either coal or ACFs.

  11. Influence of the Pyrolysis Temperature on Sewage Sludge Product Distribution, Bio-Oil, and Char Properties

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Dam-Johansen, Kim

    2013-01-01

    centrifugel reactor (PCR) at 475, 525, 575, and 625 °C. Maxima of both organic oil yield of 41 wt % on a dry ash free feedstock basis (daf) and a sludge oil energy recovery of 50% were obtained at 575 °C. The water-insoluble fraction, molecular-weight distribution, higher heating value (HHV), and thermal......Fast pyrolysis may be used for sewage sludge treatment with the advantages of a significant reduction of solid waste volume and production of a bio-oil that can be used as fuel. A study of the influence of the reaction temperature on sewage sludge pyrolysis has been carried out using a pyrolysis...... of 392 g/mol, and metal concentrations lower than 0.14 wt % on a dry basis (db). Less optimal oil properties with respect to industrial applications were observed for oil samples obtained at 475 and 625 °C. Char properties of the 575 °C sample were an ash content of 81 wt % and a HHV of 6.1 MJ/kg db...

  12. Determination of reactivity parameters of model carbons, cokes and flame-chars

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst; Gjernes, Erik; Jessen, Thomas

    1996-01-01

    be separated into a chemical kinetics expression and a structural profile describing reactivity evolution during conversion. Determinations of the reactivity profiles have been performed for reaction rates varying up to a factor of 100 and for burn-off from 20 up to 80%. The apparent reaction order...... and activation energy in oxygen are estimated for each sample over a 100 K temperature range (cases vary from 573 to 885 K) and a maximum oxygen partial pressure range of 0.01-1 bar. For the different fuel samples reaction orders range fromn =0.65 to 0.78, and global activation energies are found in the narrow...... range of 130-133 kJ/mol. For Carboxen n=0.91 and E=146 kJ/mol. The reactivity differences between the coal chars are proposed mainly due to variations in the physical structure. Over the pressure-temperature domain examined reactivity varies considerably, but the structural profile is approximately...

  13. Behavior of mineral matters in Chinese coal ash melting during char-CO{sub 2}/H{sub 2}O gasification reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xiaojiang Wu; Zhongxiao Zhang; Guilin Piao; Xiang He; Yushuang Chen; Nobusuke Kobayashi; Shigekatsu Mori; Yoshinori Itaya [University of Shanghai for Science & Technology, Shanghai (China). Department of Power Engineering

    2009-05-15

    The typical Chinese coal ash melting behavior during char-CO{sub 2}/H{sub 2}O gasification reaction was studied by using TGA, XRD, and SEM-EDX analysis. It was found that ash melting behavior during char gasification reaction is quite different from that during coal combustion process. Far from the simultaneously ash melting behavior during coal combustion, the initial melting behavior of ash usually occurs at a middle or later stage of char-CO{sub 2}/H{sub 2}O reaction because of endothermic reaction and more reactivity of char gasification reaction as compared with that of mineral melting reactions in ash. In general, the initial melting temperature of ash is as low as 200-300 K below the deformation temperature (T{sub def}) of ash with ASTM test. The initial molten parts in ash are mainly caused by iron bearing minerals such as wustite and iron-rich ferrite phases under gasification condition. Along with the proceeding of ash melting, the melting behavior appears to be accelerated by the presence of calcium to form eutectic mixtures in the FeO-SiO{sub 2}-Al{sub 2}O{sub 3} and CaO-SiO{sub 2}-Al{sub 2}O{sub 3} system. The different states of iron are the dominant reason for different melting behaviors under gasification and combustion conditions. Even under both reducing conditions, the ash fusion temperature (AFT) of coal under char-CO{sub 2} reaction is about 50-100 K lower than that under char-H{sub 2}O reaction condition. The main reason of that is the higher content of CO under char-CO{sub 2} reaction, which can get a lower ratio of Fe{sup 3+}/{Sigma}Fe in NaO-Al{sub 2}O{sub 3}-SiO{sub 2}-FeO melts. 38 refs., 8 figs., 4 tabs.

  14. Performance prediction and validation of equilibrium modeling for gasification of cashew nut shell char

    Directory of Open Access Journals (Sweden)

    M. Venkata Ramanan

    2008-09-01

    Full Text Available Cashew nut shell, a waste product obtained during deshelling of cashew kernels, had in the past been deemed unfit as a fuel for gasification owing to its high occluded oil content. The oil, a source of natural phenol, oozes upon gasification, thereby clogging the gasifier throat, downstream equipment and associated utilities with oil, resulting in ineffective gasification and premature failure of utilities due to its corrosive characteristics. To overcome this drawback, the cashew shells were de-oiled by charring in closed chambers and were subsequently gasified in an autothermal downdraft gasifier. Equilibrium modeling was carried out to predict the producer gas composition under varying performance influencing parameters, viz., equivalence ratio (ER, reaction temperature (RT and moisture content (MC. The results were compared with the experimental output and are presented in this paper. The model is quite satisfactory with the experimental outcome at the ER applicable to gasification systems, i.e., 0.15 to 0.30. The results show that the mole fraction of (i H2, CO and CH4 decreases while (N2 + H2O and CO2 increases with ER, (ii H2 and CO increases while CH4, (N2 + H2O and CO2 decreases with reaction temperature, (iii H2, CH4, CO2 and (N2 + H2O increases while CO decreases with moisture content. However at an equivalence ratio less than 0.15, the model predicts an unrealistic composition and is observed to be non valid below this ER.

  15. Reforming sewage sludge pyrolysis volatile with Fe-embedded char: Minimization of liquid product yield.

    Science.gov (United States)

    Yu, Guotao; Chen, Dezhen; Arena, Umberto; Huang, Zhen; Dai, Xiaohu

    2017-08-10

    Obtaining high quality syngas from sewage sludge (SS) means transferring a low-grade SS into a high-grade fuel or raw materials for chemical products. In this study, Fe is added to SS in form of Fe2(SO4)3 to produce an effective and self-sufficient catalyst in order to obtain more syngas and minimize liquid products from SS pyrolysis. The Fe-embedded sewage sludge chars (SSCs) were used as catalysts for volatile reforming at 600°C. It has been found that the gas yield increases from 15.9 to 35.8wt% of the SS and that of liquids decreases from 31.9 to 10.2wt% after volatile reforming with Fe-embedded SSC when Fe was added equal to 7 % in the dried SS. In addition, the content of nitrogen-containing compounds in the oily products decreased. After reforming with Fe-embedded SSC, the molar fractions of syngas combustible components, including H2, CH4 and CO, increase, and the higher heating value of the syngas increased to 17.0MJ/Nm(3) from the original 12.5MJ/Nm(3) obtained from SS pyrolysis at 550°C. Moreover, the volatile reforming seems to reduce the level of some important syngas pollutants, like H2S, HCl and HCN, even though it was also observed an increase of the contents of SO2, NH3, NO2, HCNO and N2O. Copyright © 2017. Published by Elsevier Ltd.

  16. Basic study of charring detection at the laser catheter-tip using back scattering light measurement during therapeutic laser irradiation in blood.

    Science.gov (United States)

    Takahashi, Mei; Ito, Arisa; Kajihara, Takuro; Matsuo, Hiroki; Arai, Tsunenori

    2010-01-01

    The purpose of this study is to investigate transient process of the charring at the laser catheter-tip in blood during therapeutic laser irradiation by the back scattering light measurement to detect precursor state of the charring. We took account of using photodynamic therapy for arrhythmia in blood through the laser catheter. We observed the influence of the red laser irradiation (λ=663 nm) upon the shape of red blood cells (RBCs). The RBCs aggregation, round formation, and hemolysis were took place sequentially before charring. With a model blood sandwiched between glass plates simulated as a catheter-tip boundary, we measured diffuse-reflected-light power and transmitted-light power simultaneously and continuously by a microscopic optics during the laser irradiation. We found that measured light power changes were originated with RBCs shape change induced by temperature rise due to the laser irradiation. A gentle peak following a slow descending was observed in the diffuse-reflected-light power history. This history might indicate the precursor state of the charring, in which the hemolysis might be considered to advance rapidly. We think that the measurement of diffuse-reflected-light power history might be able to detect precursor state of charring at the catheter-tip in blood.

  17. Analysis of Porous Structure Parameters of Biomass Chars Versus Bituminous Coal and Lignite Carbonized at High Pressure and Temperature—A Chemometric Study

    Directory of Open Access Journals (Sweden)

    Adam Smoliński

    2017-09-01

    Full Text Available The characteristics of the porous structure of carbonized materials affect their physical properties, such as density or strength, their sorption capacity, and their reactivity in thermochemical processing, determining both their applicability as fuels or sorbents and their efficiency in various processes. The porous structure of chars is shaped by the combined effects of physical and chemical properties of a carbonaceous material and the operating parameters applied in the carbonization process. In the study presented, the experimental dataset covering parameters of various fuels, ranging from biomass through lignite to bituminous coal, and chars produced at 1273 K and under the pressure of 1, 2, 3, and 4 MPa was analyzed with the application of the advanced method of data exploration. The principal component analysis showed that the sample of the highest coal rank was characterized by lower values of parameters reflecting the development of the porous structure of chars. A negative correlation was also observed between the carbon content in a fuel and the evolution of the porous structure of chars at high pressure. The highest total pore volume of chars produced under 1 and 3 MPa and the highest micropore surface area under 3 MPa were reported for a carbonized fuel sample of the highest moisture content.

  18. Utilization of CO2 and biomass char derived from pyrolysis of Dunaliella salina: the effects of steam and catalyst on CO and H2 gas production.

    Science.gov (United States)

    Yang, Chao; Jia, Lishan; Su, Shuai; Tian, Zhongbiao; Song, Qianqian; Fang, Weiping; Chen, Changping; Liu, Guangfa

    2012-04-01

    Biomass char, by-product of Dunaliella salina pyrolysis at a final pyrolysis temperature of 500°C, was used as feedstock material in this study. The reactions of biomass char with CO(2) were performed in a fixed-bed reactor to evaluate the effect of temperature and steam on the CO(2) conversion, CO yield and gas composition. The CO(2) conversion and CO yield without steam and catalyst reached about 61.84% and 0.99mol/(mol CO(2)) at 800°C, respectively. Steam and high temperature led to high CO(2) conversion. A new approach for improving H(2) was carried out by using biomass char and Au/Al(2)O(3) catalyst, which combined steam gasification of biomass char and water gas shift reaction, and the H(2) concentration was 1.8 times higher than without catalyst. The process not only mitigated CO(2) emission and made use of residual biomass char, but also created renewable source. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Comparison of molecular sieve properties in microporous chars from low-rank bituminous coal activated by steam and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Jasienko-Halat, M.; Kedzior, K. [Wroclaw Univ. of Technology (Poland). Inst. of Chemistry and Technology of Petroluem and Coal

    2005-07-01

    A Polish high volatile bituminous coal was subjected to air oxidation, carbonization and gaseous activation. The activation with steam and carbon dioxide was performed to low levels of burn-off: 5-25%. Sorption measurements Of CO{sub 2}, as well as of organic vapours with increasing molecular sizes (CH{sub 2}Cl{sub 2}, C{sub 6}H{sub 6}, C{sub 6}H{sub 12}, CCl{sub 4}) were applied to evaluate the porous structure of the activated chars. Steam and carbon dioxide develop the microporous system according to the same mechanism-opening (burn-off 5-10%) and then widening of the narrow micropores. For char from the oxidized coal mainly a widening of the narrow micropores takes place. Comparing both activating agents, it was stated that for steam greater micropore volumes were obtained. This was confirmed by other authors for chars from brown coal and coking coal, but was in disagreement with the results for olive stones and carbon fibres. This would indicate the importance of the carbon precursor in the formation of the porous structure of carbon materials by different activating agents. In the region of studied burn-offs, among the micropore sizes useful for separation of gases and vapours with small molecules, micropore volumes with widths close to 0.4-0.5 nm are dominating. At very low burn-offs (5-10%), steam activation renders greater micropore volumes within these sizes, than does activation with carbon dioxide. But with increasing burn-off (15-25%), this phenomenon becomes reversed. This effect is still more accentuated for the preoxidized coal.

  20. Effects of pyrolysis conditions on the porous structure construction of mesoporous charred carbon from used cigarette filters

    Science.gov (United States)

    Masoudi Soltani, Salman; Yazdi, Sara Kazemi; Hosseini, Soraya

    2014-06-01

    One-step pyrolysis was applied to synthesize mesoporous charred carbon from used cigarette filters. Proximate analysis suggested that cigarette filters are decent carbon precursors due to their moderate carbon (around 11 %) and low ash (around 0.1 %) contents. To investigate the effects of pyrolysis parameters on porous surface area, a full factorial design of experiment including heating rate, soaking time and pyrolysis temperature was used with each factor at three levels. The analysis of variance revealed that the temperature and heating rate had the most significant effects on total surface area of the synthesized carbon. Response surface model (RSM) was applied to best fit a surface through the experimental data. It was seen that the quadratic RSM model with a reasonable R 2 value of 63 % was the best developed model. The maximum BET surface area (597 m2/g) was reached at a pyrolysis temperature of 900 °C when the precursor was heated at 5 °C/min and hold at this temperature for 3 h. The produced N2 adsorption-desorption isotherm showed a certain degree of mesoporosity in the charred carbon with an average pore size of 3.32 nm calculated by Barrett-Joyner-Halenda method. Scanning electron microscopy also showed the presence of macroporosity on the charred carbon surface. Fourier transform infrared spectroscopy revealed the presence of acidic surface functional groups such as carboxyl and phenol which were accordingly confirmed by Boehm titration. In addition, Boehm titration showed that the produced carbon's surface was more acidic than basic in nature.

  1. Potential of aeration flow rate and bio-char addition to reduce greenhouse gas and ammonia emissions during manure composting.

    Science.gov (United States)

    Chowdhury, Md Albarune; de Neergaard, Andreas; Jensen, Lars Stoumann

    2014-02-01

    Aeration is an important factor influencing CO2, CH4, N2O and NH3 emissions from the composting process. Both CH4 and N2O are potent greenhouse gases (GHG) of high importance. Here, we examined the effects of high and low aeration rates together with addition of barley straw with and without bio-char on GHG and NH3 emissions from composting cattle slurry and hen manure in small-scale laboratory composters. Depending on treatment, cumulative C losses via CO2 and CH4 emissions accounted for 11.4-22.5% and 0.004-0.2% of initial total carbon, while N losses as N2O and NH3 emissions comprised 0.05-0.1% and 0.8-26.5% of initial total nitrogen, respectively. Decreasing the flow rate reduced cumulative NH3 losses non-significantly (by 88%) but significantly increased CH4 losses (by 51%) from composting of cattle slurry with barley straw. Among the hen manure treatments evaluated, bio-char addition to composting hen manure and barley straw at low flow rates proved most effective in reducing cumulative NH3 and CH4 losses. Addition of bio-char in combination with barley straw to hen manure at both high and low flow rates reduced total GHG emissions (as CO2-equivalents) by 27-32% compared with barley straw addition alone. Comparisons of flow rates showed that low flow could be an alternative strategy for reducing NH3 losses without any significant change in N2O emissions, pointing to the need for well-controlled composting conditions if gaseous emissions are to be minimised. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Canções, filmes e divas de Pubis Angelical na música de Charly Garcia (1972-1982

    Directory of Open Access Journals (Sweden)

    Júlio Ogas

    2011-06-01

    Full Text Available In the first stage of Charly García‟s production, the cinema plays an important role. Several single songs, a thematic record and the music of two films are clear indications in this regard. The meaning space that opens from this subject allows appreciating some ideas that prevail in the author's proposal. Both the literal and the symbolic languages combine to convey a message of change to man extent but deeply involved in the social environment of his time.

  3. Utilization of cotton plant ash and char for removal of 2, 4-dichlorophenoxyacetic acid

    Directory of Open Access Journals (Sweden)

    Nikhilesh S. Trivedi

    2016-12-01

    Full Text Available Cotton is a common Indian crop grown on a considerable portion of farmland across the country. After separating the useful product (cotton fibers, the other parts of the plant (stalks, leaves, etc. are discarded as wastes. In most cases, these plant materials are used as fuel in boilers or households. Cotton wastes when ignited in the presence and absence of air produce cotton plant ash (CPA and cotton plant char (CPC, respectively. However, CPA and CPC produced pose environmental problems such as safe disposal. Thus, there is an urgent need to characterize the physical and chemical properties of these derivatives and to identify their potential uses. This study highlights the potential utilization of CPA and CPC as adsorbents of 2,4-D. The main components in CPA, namely, CaO and K2O, provide micronutrients to the soil and are thus useful as a biofertilizers. Moreover, low manufacturing cost and higher availability favor the use of CPA as an efficient, low-cost adsorbent as well as a potential source of vital micronutrients. The adsorption capacity of CPA and CPC was tested using 2,4 dichlorophenoxyacetic acid (2,4-D as the representative herbicide. Experimental data were analyzed by Freundlich and Langmuir adsorption isotherms, and these fitted well with the Langmuir model. The adsorption capacity q0 was found to be 0.64 mg/g for CPA and 3.93 mg/g for CPC. Pseudo-first-order pseudo-second-order and intraparticle diffusion kinetic models were applied to experimental data, and the pseudo second order kinetics model showed best fit for the adsorption of 2,4-D on CPA and CPC. Both CPA and CPC were characterized using proximate analysis, SEM images, BET surface area, XRF, FTIR, and CHNS. The BET surface area was found to be 2 and 109 m2/g, respectively, for CPA and CPC. Adsorption study results indicated that both CPA and CPC are very effective cheap adsorbent for 2,4-D removal.

  4. Fıxed bed slow pyrolysıs of bıomass solıd waste for bıo-char

    Science.gov (United States)

    Islam, M. N.; Ali, M. H.; Ahmad, I.

    2017-06-01

    Biomass solid waste in the form of rice husk particle is pyrolyzed in a fixed bed pyrolysis reactor. The reactor is made of stainless steel with dimensions of 76 mm in diameter and 90 cm in length. Rice husk is collected locally from Brunei-Muara district of Brunei Darussalam which is processed for pyrolysis. The particles are selected in the millimeter range. It is oven-dried at 105°C for 6 hours after being air-dried prior to pyrolysis. The reactor bed is heated by means of saw-dust in a biomass source heater. A temperature range of 390-410°C is maintained with an apperent vapor residence time of 30 min. Nitrogen gas is passed through the reactor system to make the atmosphere inert. A water-cooled condenser is used to derive bio-oil from the condensable vapors. The system is subjected to pyrolysis for a running time of 60 min. The products obtained are solid bio-char, liquid bio-oil and pyrolytic bio-gases. The solid char yield is found to be 45 by weight of solid biomass feedstock and the liquid product yield is found to be 29 by weight of solid biomass feedstock. The rest is gas flared into the atmosphere. The bio-char is retained in the reactor and collected at the end of the experimental run. The bio-char is found to be black in color retaining its original shape. The bio-char product is subjected to energy analysis for its higher heating value (HHV) by means of an oxygen bomb calorimeter. It is found to be 20.3 MJ/kg. The density of the bio-char is found to be 238.5 kg/m3 with an energy density of 4.85 GJ/m3.

  5. Coal combustion science: Task 1, Coal char combustion: Task 2, Fate of mineral matter. Quarterly progress report, July--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.; Hurt, R.H.; Davis, K.A.; Baxter, L.L.

    1994-07-01

    Progress reports are presented for the following tasks: (1) kinetics and mechanisms of pulverized coal char combustion and (2) fate of inorganic material during coal combustion. The objective of Task 1 is to characterize the combustion behavior of selected US coals under conditions relevant to industrial pulverized coal-fired furnaces. In Sandia`s Coal Combustion Laboratory (CCL), optical techniques are used to obtain high-resolution images of individual burning coal char particles and to measure, in situ, their temperatures, sizes, and velocities. Detailed models of combustion transport processes are then used to determine kinetic parameters describing the combustion behavior as a function of coal type and combustion environment. Partially reacted char particles are also sampled and characterized with advanced materials diagnostics to understand the critical physical and chemical transformations that influence reaction rates and burnout times. The ultimate goal of the task is the establishment of a data base of the high temperature reactivities of chars from strategic US coals, from which important trends may be identified and predictive capabilities developed. The overall objectives for task 2 are: (1) to complete experimental and theoretical investigation of ash release mechanisms; (2) to complete experimental work on char fragmentation; (3) to establish the extent of coal (as opposed to char) fragmentation as a function of coal type and particle size; (4) to develop diagnostic capabilities for in situ, real-time, qualitative indications of surface species composition during ash deposition, with work continuing into FY94; (5) to develop diagnostic capabilities for in situ, real-time qualitative detection of inorganic vapor concentrations; and (6) to conduct a literature survey on the current state of understanding of ash deposition, with work continuing into FY94.

  6. Effect of sewage sledge and their bio-char on some soil qualities in Second year cropping

    Science.gov (United States)

    fathi dokht, hamed; Movahedi Naeini, Seyed Alireza; Dordipor, Esmaeil; mirzanejad, moujan

    2016-04-01

    Bio char (BC) application as a soil amendment has achieved much interest and has been found that considerably improves soil nutrient status and crop yields on poor soils. However, information on the effect of BC on illitic soils in temperate climates is still insufficient. The primary objective in this study was to assess the influence of sewage sledge and their bio-char on the soil physical properties, nutrient status and plant production in Second year cropping. The result may also provide a reference for the use of biochars as a solution in agricultural waste management when sludge with considerable load of pathogens are involved. Soybean was already grown one year and will be repeated one more year with same treatments. The investigated soil properties included soil water content and mechanical resistance, pH, electrical conductivity (EC), calcium- acetate-lactate (CAL)-extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show soil water content, potassium uptake and plant yield were increased. Heating sludge removed all pathogens and soybean yield was increased by 7%.

  7. Odor and VOC Emissions from Pan Frying of Mackerel at Three Stages: Raw, Well-Done, and Charred

    Directory of Open Access Journals (Sweden)

    Jeong-Hyeon Ahn

    2014-11-01

    Full Text Available Many classes of odorants and volatile organic compounds that are deleterious to our wellbeing can be emitted from diverse cooking activities. Once emitted, they can persist in our living space for varying durations. In this study, various volatile organic compounds released prior to and during the pan frying of fish (mackerel were analyzed at three different cooking stages (stage 1 = raw (R, stage 2 = well-done (W, and stage 3 = overcooked/charred (O. Generally, most volatile organic compounds recorded their highest concentration levels at stage 3 (O, e.g., 465 (trimethylamine and 106 ppb (acetic acid. In contrast, at stage 2 (W, the lowest volatile organic compounds emissions were observed. The overall results of this study confirm that trimethylamine is identified as the strongest odorous compound, especially prior to cooking (stage 1 (R and during overcooking leading to charring (stage 3 (O. As there is a paucity of research effort to measure odor intensities from pan frying of mackerel, this study will provide valuable information regarding the management of indoor air quality.

  8. Preparation and characterisation of raw chars and physically activated carbons derived from marine Posidonia oceanica (L.) fibres

    Energy Technology Data Exchange (ETDEWEB)

    Ncibi, M.C., E-mail: ncibi_mc@yahoo.com [Laboratoire de chimie, Institut Superieur Agronomique, Chott Meriem 4042, Sousse (Tunisia); Unite de Recherche ' Chimie Appliquee et Environnement' , EPAM Sousse 4000 (Tunisia); Laboratoire COVACHIMM, EA 3592 Universite des Antilles et de la Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe (France); Jeanne-Rose, V. [Laboratoire COVACHIMM, EA 3592 Universite des Antilles et de la Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe (France); Mahjoub, B. [Laboratoire de chimie, Institut Superieur Agronomique, Chott Meriem 4042, Sousse (Tunisia); Unite de Recherche ' Chimie Appliquee et Environnement' , EPAM Sousse 4000 (Tunisia); Jean-Marius, C. [Laboratoire COVACHIMM, EA 3592 Universite des Antilles et de la Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe (France); Lambert, J.; Ehrhardt, J.J. [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, UMR 7564 CNRS, Universites de Nancy, 405, rue de Vandoeuvre, F 56600 Villers-les-Nancy cedex (France); Bercion, Y. [Groupe de Technologie des Surfaces et Interfaces (GTSI), EA 2432, Faculte des Sciences Exactes et Naturelles, Universite des Antilles et de la Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe (France); Seffen, M. [Laboratoire de chimie, Institut Superieur Agronomique, Chott Meriem 4042, Sousse (Tunisia); Unite de Recherche ' Chimie Appliquee et Environnement' , EPAM Sousse 4000 (Tunisia); Gaspard, S. [Laboratoire COVACHIMM, EA 3592 Universite des Antilles et de la Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe (France)

    2009-06-15

    Industrial valorisation of low cost and renewable biomass as raw precursor of activated carbon for environmental applications is an interesting alternative to costly commercial activated carbons. In this study, the possible use of Mediterranean, Posidonia oceanica fibrous biomass, as a precursor for chars and physically activated carbons, is investigated. Firstly, the raw marine material was chemically and biochemically characterised throughout dry-basis elemental, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis. Then, several P. oceanica chars were prepared and characterised under different pyrolysis times and temperatures. In addition, physically activated carbons (PACs) were produced via water steam flow under various activation periods. The results showed that the pyrolysis induces the creation of pores at different levels with respect to the involved temperature. Thereafter, the physical activation tends to enhance the development of the porous structure. In that issue, the performed Brunauer-Emmett-Teller (BET) and Barrett-Joiner-Halenda (BJH) analysis revealed that the prepared PACs have a mainly mesoporous inner morphology with a varying fraction of micropores.

  9. Retrofitting hetrotrophically cultivated algae biomass as pyrolytic feedstock for biogas, bio-char and bio-oil production encompassing biorefinery.

    Science.gov (United States)

    Sarkar, Omprakash; Agarwal, Manu; Naresh Kumar, A; Venkata Mohan, S

    2015-02-01

    Algal biomass grown hetrotrophically in domestic wastewater was evaluated as pyrolytic feedstock for harnessing biogas, bio-oil and bio-char. Freshly harvested microalgae (MA) and lipid extracted microalgae (LEMA) were pyrolysed in packed bed reactor in the presence and absence of sand as additive. MA (without sand additive) depicted higher biogas (420 ml/g; 800 °C; 3 h) and bio-oil (0.70 ml/g; 500 °C; 3 h). Sand addition enhanced biogas production (210 ml/g; 600 °C; 2 h) in LEMA operation. The composition of bio-gas and bio-oil was found to depend on the nature of feedstock as well as the process conditions viz., pyrolytic-temperature, retention time and presence of additive. Sand additive improved the H2 composition while pyrolytic temperature increment caused a decline in CO2 fraction. Bio-char productivity increased with increasing temperature specifically with LEMA. Integration of thermo-chemical process with microalgae cultivation showed to yield multiple resources and accounts for environmental sustainability in the bio-refinery framework. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. TRP0033 - PCI Coal Combustion Behavior and Residual Coal Char Carryover in the Blast Furnace of 3 American Steel Companies during Pulverized Coal Injection (PCI) at High Rates

    Energy Technology Data Exchange (ETDEWEB)

    Veena Sahajwalla; Sushil Gupta

    2005-04-15

    Combustion behavior of pulverized coals (PC), gasification and thermal annealing of cokes were investigated under controlled environments. Physical and chemical properties of PCI, coke and carbon residues of blast furnace dust/sludge samples were characterized. The strong influence of carbon structure and minerals on PCI reactivity was demonstrated. A technique to characterize char carryover in off gas emissions was established.

  11. Combustion studies in a fluidised bed-The link between temperature, NO{sub x} and N{sub 2}O formation, char morphology and coal type

    Energy Technology Data Exchange (ETDEWEB)

    Valentim, B.; Lemos de Sousa, M.J. [Centro de Geologia da Universidade do Porto, Faculdade de Ciencias, Praca de Gomes Teixeira, 4099-002, Porto (Portugal); Abelha, P.; Boavida, D.; Gulyurtlu, I. [Departamento de Engenharia Energetica e Controlo Ambiental (DEECA), Instituto Nacional de Engenharia, Tecnologia e Inovacao (INETI), Estrada do Paco do Lumiar, 22, Edif. J, 1649-038, Lisboa (Portugal)

    2006-06-06

    Five commercially available high volatile bituminous coals from different origins were studied with the objective of characterizing their petrographic nature with respect to emissions of NO{sub x} and N{sub 2}O. The chars produced [at temperatures ranging from 700 to 1000 {sup o}C] from these coals were also petrographic ally analyzed to assess the contribution of char to NO{sub x} and N{sub 2}O formation during combustion. Vitrinite-rich coals produced higher porous chars (cenospheres and tenuinetworks) than those that are rich in inertinite. The former coals were, however, found to release lower concentrations of NO. Consistent with previous works, N{sub 2}O emissions were observed to decrease significantly with temperature, however, on the whole, the N{sub 2}O emissions from vitrinite-rich high volatile coals were less than those from inertinite-rich coals. Additionally, high porous chars were found to give rise to lower emissions of NO and N{sub 2}O. (author)

  12. Rapid co-pyrolysis of rice straw and a bituminous coal in a high-frequency furnace and gasification of the residual char.

    Science.gov (United States)

    Yuan, Shuai; Dai, Zheng-hua; Zhou, Zhi-jie; Chen, Xue-li; Yu, Guang-suo; Wang, Fu-chen

    2012-04-01

    Rapid pyrolysis of rice straw (RS) and Shenfu bituminous coal (SB) separately, and rapid co-pyrolysis of RS/SB blends (mass ratio 1:4, 1:4, and 4:1), were carried out in a high-frequency furnace which can ensure both high heating rate and satisfying contact of fuel particles. Synergies between RS and SB during rapid co-pyrolysis were investigated. Intrinsic and morphological structures of residual char from co-pyrolysis, and their effects on gasification characteristics were also studied. Synergies occurred during rapid co-pyrolysis of RS and SB (RS/SB=1:4) resulting in decreasing char yields and increasing volatile yields. Synergies also happened during gasification of the char derived from co-pyrolysis of RS and SB with mass ratio of 1:4. The increased mass ratio of RS to SB did not only weaken synergies during co-pyrolysis, but significantly reduced the gasification rates of the co-pyrolysis char compared to the calculated values. Results can help to optimize co-conversion process of biomass/coal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Thermal characteristics and surface morphology of char during co-pyrolysis of low-rank coal blended with microalgal biomass: Effects of Nannochloropsis and Chlorella.

    Science.gov (United States)

    Wu, Zhiqiang; Yang, Wangcai; Yang, Bolun

    2018-02-01

    In this work, the influence of Nannochloropsis and Chlorella on the thermal behavior and surface morphology of char during the co-pyrolysis process were explored. Thermogravimetric and iso-conversional methods were applied to analyzing the pyrolytic and kinetic characteristics for different mass ratios of microalgae and low-rank coal (0, 3:1, 1:1, 1:3 and 1). Fractal theory was used to quantitatively determine the effect of microalgae on the morphological texture of co-pyrolysis char. The result indicated that both the Nannochloropsis and Chlorella promoted the release of volatile from low-rank coal. Different synergistic effects on the thermal parameters and yield of volatile were observed, which could be attributed to the different compositions in the Nannochloropsis and Chlorella and operating condition. The distribution of activation energies shows nonadditive characteristics. Fractal dimensions of the co-pyrolysis char were higher than the individual char, indicating the promotion of disordered degree due to the addition of microalgae. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Study on demetalization of sewage sludge by sequential extraction before liquefaction for the production of cleaner bio-oil and bio-char.

    Science.gov (United States)

    Leng, Lijian; Yuan, Xingzhong; Shao, Jianguang; Huang, Huajun; Wang, Hou; Li, Hui; Chen, Xiaohong; Zeng, Guangming

    2016-01-01

    Demetalization of sewage sludge (SS) by sequential extraction before liquefaction was implemented to produce cleaner bio-char and bio-oil. Demetalization steps 1 and 2 did not cause much organic matter loss on SS, and thus the bio-oil and bio-char yields and the compositions of bio-oils were also not affected significantly. However, the demetalization procedures resulted in the production of cleaner bio-chars and bio-oils. The total concentrations and the acid soluble/exchangeable fraction (F1 fraction, the most toxic heavy metal fraction) of heavy metals (Cu, Cr, Pb, Zn, and Cd) in these products were significantly reduced and the environmental risks of these products were also relived considerably compared with those produced from raw SS, respectively. Additionally, these bio-oils had less heavy fractions. Demetalization processes with removal of F1 and F2 fractions of heavy metals would benefit the production of cleaner bio-char and bio-oil by liquefaction of heavy metal abundant biomass like SS. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Valorization of algal waste via pyrolysis in a fixed-bed reactor: Production and characterization of bio-oil and bio-char.

    Science.gov (United States)

    Aboulkas, A; Hammani, H; El Achaby, M; Bilal, E; Barakat, A; El Harfi, K

    2017-11-01

    The aim of the present work is to develop processes for the production of bio-oil and bio-char from algae waste using the pyrolysis at controlled conditions. The pyrolysis was carried out at different temperatures 400-600°C and different heating rates 5-50°C/min. The algal waste, bio-oil and bio-char were successfully characterized using Elemental analysis, Chemical composition, TGA, FTIR, 1H NMR, GC-MS and SEM. At a temperature of 500°C and a heating rate of 10°C/min, the maximum yield of bio-oil and bio-char was found to be 24.10 and 44.01wt%, respectively, which was found to be strongly influenced by the temperature variation, and weakly affected by the heating rate variation. Results show that the bio-oil cannot be used as bio-fuel, but can be used as a source of value-added chemicals. On the other hand, the bio-char is a promising candidate for solid fuel applications and for the production of carbon materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Promotion of hydrogen-rich gas and phenolic-rich bio-oil production from green macroalgae Cladophora glomerata via pyrolysis over its bio-char.

    Science.gov (United States)

    Norouzi, Omid; Jafarian, Sajedeh; Safari, Farid; Tavasoli, Ahmad; Nejati, Behnam

    2016-11-01

    Conversion of Cladophora glomerata (C. glomerata) as a Caspian Sea's green macroalgae into gaseous, liquid and solid products was carried out via pyrolysis at different temperatures to determine its potential for bio-oil and hydrogen-rich gas production for further industrial utilization. Non-catalytic tests were performed to determine the optimum condition for bio-oil production. The highest portion of bio-oil was retrieved at 500°C. The catalytic test was performed using the bio-char derived at 500°C as a catalyst. Effect of the addition of the algal bio-char on the composition of the bio-oil and also gaseous products was investigated. Pyrolysis derived bio-char was characterized by BET, FESEM and ICP method to show its surface area, porosity, and presence of inorganic metals on its surface, respectively. Phenols were increased from 8.5 to 20.76area% by the addition of bio-char. Moreover, the hydrogen concentration and hydrogen selectivity were also enhanced by the factors of 1.37, 1.59 respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Pyrolysis of Lantana camara and Mimosa pigra: Influences of temperature, other process parameters and incondensable gas evolution on char yield and higher heating value.

    Science.gov (United States)

    Mundike, Jhonnah; Collard, François-Xavier; Görgens, Johann F

    2017-11-01

    Pyrolysis of invasive non-indigenous plants, Lantana camara (LC) and Mimosa pigra (MP) was conducted at milligram-scale for optimisation of temperature, heating rate and hold time on char yield and higher heating value (HHV). The impact of scaling-up to gram-scale was also studied, with chromatography used to correlate gas composition with HHV evolution. Statistically significant effects of temperature on char yield and HHV were obtained, while heating rate and hold time effects were insignificant. Milligram-scale maximised HHVs were 30.03MJkg(-1) (525°C) and 31.01MJkg(-1) (580°C) for LC and MP, respectively. Higher char yields and HHVs for MP were attributed to increased lignin content. Scaling-up promoted secondary char formation thereby increasing HHVs, 30.82MJkg(-1) for LC and 31.61MJkg(-1) for MP. Incondensable gas analysis showed that temperature increase beyond preferred values caused dehydrogenation that decreased HHV. Similarly, CO evolution profile explained differences in optimal HHV temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Potential of aeration flow rate and bio-char addition to reduce greenhouse gas and ammonia emissions during manure composting

    DEFF Research Database (Denmark)

    Chowdhury, Md Albarune; de Neergaard, Andreas; Jensen, Lars Stoumann

    2014-01-01

    Aeration is an important factor influencing CO2, CH4, N2O and NH3 emissions from the composting process. Both CH4 and N2O are potent greenhouse gases (GHG) of high importance. Here, we examined the effects of high and low aeration rates together with addition of barley straw with and without bio...... to composting hen manure and barley straw at low flow rates proved most effective in reducing cumulative NH3 and CH4 losses. Addition of bio-char in combination with barley straw to hen manure at both high and low flow rates reduced total GHG emissions (as CO2-equivalents) by 27-32% compared with barley straw...

  19. Combustion of Illinois coals and chars with natural gas. Final technical report, September 1, 1991--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Buckius, R.O.; Peters, J.E.; Krier, H. [Illinois Univ., Urbana-Champaign, IL (United States)

    1992-12-31

    Combined combustion of coal and natural gas offers advantages compared to burning coal or natural gas alone. For example, low volatile coals (or chars) derived from treatment or gasification processes can be of limited use due to their poor flammability characteristics. However, the use of natural gas in conjunction with the solid fuel can provide the necessary ``volatiles`` to enhance the combustion. Also, natural gas provides a clean cofiring fuel source which can enhance the usefulness of coals with high sulfur content. Addition of natural gas may reduce SO{sub x} emissions through increased sulfur retention in the ash and reduce NO{sub x} emissions by varying local stoichiometry and temperature levels. This research program addresses the contributions and the mechanisms of cofiring natural gas with Illinois coal through studies of particle ignition, burning rates and ash characterization.

  20. Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar.

    Science.gov (United States)

    Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel

    2014-01-01

    This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm(3) at a gasification temperature of 1500 K and equivalence ratio of 0.15.

  1. Effect of smoke, charred wood, and nitrogenous compounds on seed germination of ten species from woodland in central-western Spain.

    Science.gov (United States)

    Pérez-Fernández, M A; Rodríguez-Echeverría, S

    2003-01-01

    The effect of smoke, charred wood, and nitrogenous compounds on germination was tested on 10 species of the Cistaceae, Poaceae, Fabaceae, and Asteraceae, from fire-prone, shrubby woodlands in central-western Spain. Dry seeds were exposed to smoke, by watering with distilled water-charred wood suspensions, or NaNO2, KNO3, NH4Cl, and NH4NO3. Smoke enhanced germination in 9 of 10 of the species. In species of Poaceae, germination was stimulated by 20 min of smoke exposure. In Asteraceae and Fabaceae species, 10 min of smoke exposure was the most effective treatment for enhancing germination. Three species--Cistus ladanifer, Cistus crispus, and Cistus monspeliensis--had a positive response to 20 min of smoke exposure; germination of Cistus salviifolius L. was also enhanced after 10 min. The effect of charred wood was variable, with no consistent germination pattern within the families. Trifolium angustifolium and Retama sphaerocarpa showed no stimulation of germination under most of the charred wood concentrations. Similarly, germination of Senecio jacobea under the charred wood treatment did not surpass that of the control. NaNO2 promoted seed germination in Dactylis glomerata (10 mM), Cistus ladanifer (1, 10, and 25 mM), and Cistus crispus (1 and 10 mM). KNO3 enhanced germination in Dactylis glomerata (1 and 25 mM), Dittrichia viscosa (10 and 25 mM), C. ladanifer (1, 10, and 25 mM), Cistus crispus (1 and 25 mM), and C. salviifolius aud C. monspeliensis (25 mM). NH4Cl induced germination of Dactylis glomerata and Dittrichia viscosa (1 mM), and Cistus species germinated best in 25 mM of this salt. NH4NO3 induced germination only in Cistus species. Holcus lanatus had the highest level of germination regardless of treatment.

  2. Effect of fire residues (ash and char) on microbial activity, respiration and methanogenesis in three subtropical wetland soils

    Science.gov (United States)

    Medvedeff, C.; Hogue, B.; Inglett, P.

    2011-12-01

    Prescribed fire is a common restoration and maintenance technique in the southern United States. Prescribed burns coupled with frequent natural fires in South Florida can have devastating effects on ecosystem function. To determine the effect fire residues have on carbon biogeochemical cycling litter material was obtained from two restored and one native marl wetland in Everglades National Park and manipulated in a laboratory setting to produce ash and vegetation derived char. Based on vegetation biomass removal pre and post fire (insitu) appropriate aliquots of each fire residue was added to experimental microcosms as a soil amendment. Soil enzymes (β-glucosidase, cellobiohydrolase, phosphatase, bis-phosphate and leucine amino peptidase), aerobic and anaerobic respiration (CO2) potentials, extractable C and methanogenesis were measured over a 25 day period. Regardless of site C enzymes responded to both amendments within 5 days of addition. Similarly amended soil contained more extractable carbon in the reference and one of the restored sites. In the restored sites ash and char inhibited methanogenesis, had no effect on anaerobic CO2 potentials, but stimulated aerobic respiration after ten days. In contrast, within the first ten days phosphatase enzyme activity was lower in the ash treatment when compared to the control treatment and stimulation of aerobic respiration was observed in both treatment soils. After ten days ash stimulated methanogenic processing while suppressing anaerobic CO2 production suggesting methanogens in this ecosystem may be dependant on usable carbon substrates derived from aerobic microbial processing. This study illustrates the variable response of C parameters to complete and incomplete combusted materials produced from both prescribed and natural fires with particular importance to fire adapted ecosystems.

  3. Caracterização dos produtos líquidos e do carvão da pirólise de serragem de eucalipto Characterization of liquid products and char from the pyrolysis of eucalyptus sawdust

    Directory of Open Access Journals (Sweden)

    Ayrton F. Martins

    2007-08-01

    Full Text Available This study proposes the low temperature pyrolysis as an alternative conversion process for residual biomass and for obtaining gaseous, liquid and solid chemical feedstocks. Using a bench electrical pyrolysis oven, four product fractions from eucalyptus sawdust were obtained: a gaseous one, two liquid (aqueous and oily, and a solid residue (char. These products were characterized by different analytical methods. The liquid fractions showed themselves as potential sources for input chemicals. The residual char revealed appreciable adsorption capability. The process demonstrated good efficiency, generating at least two fractions of great industrial interest: bio oil and char.

  4. Co-pyrolysis behaviour and kinetic of two typical solid wastes in China and characterisation of activated carbon prepared from pyrolytic char.

    Science.gov (United States)

    Ma, Yuhui; Niu, Ruxuan; Wang, Xiaona; Wang, Qunhui; Wang, Xiaoqiang; Sun, Xiaohong

    2014-11-01

    This is the first study on the co-pyrolysis of spent substrate of Pleurotus ostreatus and coal tar pitch, and the activated carbon prepared from the pyrolytic char. Thermogravimetry (TG) analysis was carried out taking spent substrate, coal tar pitch and spent substrate-coal tar pitch mixture. The activation energies of pyrolysis reactions were obtained via the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. The kinetic models were determined by the master-plots method. The activated carbons were characterised by N2-adsorption, Fourier transform infrared spectroscopy and X-ray diffraction. Experimental results demonstrated a synergistic effect happened during co-pyrolysis, which was characterised by a decreased maximum decomposition rate and an enhanced char yield. The average activation energies of the pyrolysis reactions of spent substrate, coal tar pitch and the mixture were 115.94, 72.92 and 94.38 kJ mol(-1) for the Flynn-Wall-Ozawa method, and 112.17, 65.62 and 89.91 kJ mol(-1) for the Kissinger-Akahira-Sunose method. The reaction model functions were f(α) = (1-α)(3.42), (1-α)(1.72) and (1-α)(3.07) for spent substrate, coal tar pitch and the mixture, respectively. The mixture char-derived activated carbon had a Brunauer-Emmett-Teller surface area up to 1337 m(2) g(-1) and a total pore volume of 0.680 cm(3) g(-1). Mixing spent substrate with coal tar pitch led to the creation of more micropores and a higher surface area compared with the single spent substrate and coal tar pitch char. Also, the mixture char-derived activated carbon had a higher proportion of aromatic stacking. This study provides a reference for the utilisation of spent substrate and coal tar pitch via co-pyrolysis, and their pyrolytic char as a promising precursor of activated carbon. © The Author(s) 2014.

  5. SiteChar. Characterisation of European CO2 storage. Deliverable 8.4. Quantitative social site characterisations

    Energy Technology Data Exchange (ETDEWEB)

    Brunsting, S.; Mastop, E.A. [ECN Policy Studies, Energy research Centre of the Netherlands ECN, Amsterdam (Netherlands); Kaiser, M.; Zimmer, R. [Unabhaengiges Institut fuer Umweltfragen UfU, Berlin (Germany)

    2013-06-15

    This report describes the results of the last stage of the in-depth social site characterisation activities at two prospective CCS sites as part of the SiteChar project: a CCS onshore site and a CCS offshore site. The onshore site is the Zalecze and Zuchlow site application (Poland - WP5) and the offshore site is the North Sea Moray Firth site (UK - WP3). This deliverable describes the results from a repeated quantitative measurement of local awareness, knowledge, and perceptions of CCS at both sites using representative surveys. For comparison and discussion of all SiteChar WP8 results we refer to the final summary report D8.5. The 2nd survey showed some interesting results. First of all, awareness of CCS was still very low. While in the UK around half of the respondents had at least heard of local plans for CCS, in Poland this was only 21%. It seems that awareness in the UK was mostly induced by specific plans in the area that were abandoned in the course of the SiteChar project. Second, it seems that on the whole the local publics were rather positive about CCS. Most respondents expected a positive impact of CCS on the region. In the UK, arguments for that were mainly economic, while in Poland arguments were mainly related to environmental concerns. Although there are some worries about risks of leakage, especially at the onshore site in Poland, people think that authorities will properly regulate CCS and monitor the safety of CCS. Expectations were mostly that it would be good for the country and that it will help reach international targets for CO2 reduction and buy time to develop renewable energy. Respondents seemed uncertain about the costs of using CCS and whether the technique is ready for widespread use. Especially in Poland people seemed to agree that CCS is essential for tackling climate change. Most differences between the two sites may be attributed to the proximity of the site to the local community. The Polish site is onshore and therefore much

  6. Pisum & Ervilia Tetovac: Made in Early Iron Age Leskovac, Part two: Extraction of the ancient DNA from charred seeds from the site of Hissar in South Serbia

    Directory of Open Access Journals (Sweden)

    Jovanović Živko

    2011-01-01

    Full Text Available The extracts were prepared from the samples of 3,200-year-old charred pea and bitter vetch seeds from the site of Hissar near Leskovac, South Serbia, using two different DNA extraction procedures. We used CTAB method with some modification and obtained low quantity of ancient DNA in comparison with the second method used - commercial available kit. After the extraction, a whole genome amplification using Phi29 DNA polymerase was performed. The amplified DNAs were used for PCR reaction using primers for 26S rDNA gene, which is located on the nuclear genome. The single band corresponding to 26S rDNA fragment from modern relatives was obtained. We conclude that DNA from charred pea and vetch seed can be extracted and used for further archaeobotanical analysis at the molecular level.

  7. Production of value-added chars and activated carbons from animal manure

    Science.gov (United States)

    The United States has a strong agricultural foundation that leaves behind large quantities of animal wastes. In the United States, an estimated 9 billion broilers, 256 million turkeys, 62 million pigs and 97 million dairy cows were produced in 2006 producing 5 times the waste of the U.S. human popu...

  8. The thermal stability and pyrolysis mechanism of boron-containing phenolic resins: The effect of phenyl borates on the char formation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shujuan; Wang, Yong; Bian, Cheng; Zhong, Yuhu [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049, People’ s Republic of China (China); Jing, Xinli, E-mail: rgfp-jing@mail.xjtu.edu.cn [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049, People’ s Republic of China (China); MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an, 710049, People’ s Republic of China (China)

    2015-03-15

    Graphical abstract: - Highlights: • The thermal stability and pyrolysis mechanism of cured BPR are investigated. • The high char yield of BPR results from the formed phenyl borates during curing. • Boron oxide is formed on the surface of carbonized product during pyrolysis. • The formed boron oxide revealed the cleavage of O–C bonds from phenyl borates. • The graphitization degree and graphite crystallites of PR are improved by introducing boron. - Abstract: Boron-containing phenolic resin (BPR) is a kind of the ablative resins with high-performance. Due to the lack of the exact knowledge concerning the pyrolysis mechanism of BPR, its development and application are greatly impeded. In the present paper, the chemical structure of the cured BPR and its structural evolution at high temperatures are investigated to clarify the reason for the high char yield of BPR. The results indicate that the high char yield of BPR is mainly attributed to the phenyl borates formed during curing, which can block parts of phenolic hydroxyl groups, and effectively inhibit their thermal decomposition reaction. Boron oxide is formed on the surface of carbonization products by the cleavage of O–C bonds from phenyl borates via pyrolysis, which avoids the release of volatile carbon dioxide and reduces the development of micro-structural defects of carbonization products. Introducing boron into PR improves the graphitization degree and graphite crystallites of carbonization products, which promotes the formation of a more ordered glassy carbon during pyrolysis. This study provides a new vision for the understanding of the high char yield of BPR, which makes it possible to develop a new ablative resin through molecular design.

  9. NO/sub x/-char reactions: Kinetics and transport aspects: Quarterly technical progress report, 1 January 1988-31 March 1988

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Suuberg, E.M.; Makhija, S.; Teng, H.; Lilly, W.D.

    1988-01-01

    Reduction of NO/sub x/ emissions from coal combustors remains among the most important unresolved environmental control problems associated with the utilization of coal. In stationary combustion devices, NO/sub x/ is produced from both nitrogen in the combustion air and from the fixed fuel nitrogen (i.e., originating from the chemical matrix of the fuel). Combustion of coal generally results in the conversion of about 15/endash/40/percent/ of the fuel nitrogen to NO. It is generally agreed that most of the primary NO/sub x/ formed in combustors is as NO rather than NO/sub 2/. The formation mechanisms of NO/sub x/ have received significant attention. NO/sub x/ formation from fuel nitrogen, for example, has been found to be dependent on a complex series of homogeneous and heterogeneous mechanistic steps. However, an understanding of NO formation is only part of the story; the development of NO control strategies must also be guided by a knowledge of its destruction mechanisms. An appreciable portion of the NO initially formed within the particle (i.e., from fuel nitrogen) can be destroyed by NO-char reactions before it can ever escape. The destruction of NO external to the particle includes both homogeneous gas phase processes and heterogeneous processes that require transport of NO to the surface, including gas-solid reactions between the char and NO, and/or catalytic reactions between absorbed species, such as NO and CO, on the char surface. Different mechanisms are believed to predominate in different situations. This difficulty in drawing firm conclusions regarding the role of heterogeneous NO/sub x/ reduction mechanisms is partly due to the fact that some aspects remain very poorly understood. The objective of this project is to develop an improved understanding of the chemical kinetics and mass transport characteristics of the heterogeneous interactions of NO/sub x/ with char. 39 refs., 6 figs., 2 tabs.

  10. Characterization and partitioning of the char ash collected after the processing of pine wood chips in a pilot-scale gasification unit

    Science.gov (United States)

    Thomas L. Eberhardt; Hui Pan; Leslie H. Groom; Chi-Leung So

    2011-01-01

    Southern yellow pine wood chips were used as the feedstock for a pilot-scale gasification unit coupled with a 25 kW generator. The pulp-grade wood chips were relatively free of bark and low in ash content. Processing this feedstock yielded a black/sooty by-product that upon combustion in a muffle furnace resulted in an ash content of about 48%. The term "char ash...

  11. Direct and indirect climatic drivers of biotic interactions: ice-cover and carbon runoff shaping Arctic char Salvelinus alpinus and brown trout Salmo trutta competitive asymmetries.

    Science.gov (United States)

    Ulvan, Eva M; Finstad, Anders G; Ugedal, Ola; Berg, Ole Kristian

    2012-01-01

    One of the major challenges in ecological climate change impact science is to untangle the climatic effects on biological interactions and indirect cascading effects through different ecosystems. Here, we test for direct and indirect climatic drivers on competitive impact of Arctic char (Salvelinus alpinus L.) on brown trout (Salmo trutta L.) along a climate gradient in central Scandinavia, spanning from coastal to high-alpine environments. As a measure of competitive impact, trout food consumption was measured using (137)Cs tracer methodology both during the ice-covered and ice-free periods, and contrasted between lakes with or without char coexistence along the climate gradient. Variation in food consumption between lakes was best described by a linear mixed effect model including a three-way interaction between the presence/absence of Arctic char, season and Secchi depth. The latter is proxy for terrestrial dissolved organic carbon run-off, strongly governed by climatic properties of the catchment. The presence of Arctic char had a negative impact on trout food consumption. However, this effect was stronger during ice-cover and in lakes receiving high carbon load from the catchment, whereas no effect of water temperature was evident. In conclusion, the length of the ice-covered period and the export of allochthonous material from the catchment are likely major, but contrasting, climatic drivers of the competitive interaction between two freshwater lake top predators. While future climatic scenarios predict shorter ice-cover duration, they also predict increased carbon run-off. The present study therefore emphasizes the complexity of cascading ecosystem effects in future effects of climate change on freshwater ecosystems.

  12. Reactivity to CO{sub 2} of chars prepared in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} mixtures for pulverized coal injection (PCI) in blast furnace in relation to char petrographic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pohlmann, Juliana G.; Osorio, Eduardo; Vilela, Antonio C.F. [Iron and Steelmaking Laboratory, UFRGS, Porto Alegre (Brazil); Borrego, Angeles G. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2010-12-01

    Pulverized coal injection (PCI) is employed in blast furnace tuyeres in order to increase the injection rate without increasing the amount of unburned char inside the stack. When coal is injected with air in the region of tuyeres, the resolidified char will burn in an atmosphere with progressively lower oxygen content and higher CO{sub 2} concentration. In this study, an experimental approach comprising refiring has been followed to separate the combustion process into two distinct devolatilization and combustion steps. A drop tube furnace (DTF) operating at 1300 C in an atmosphere with low oxygen concentration was used to simulate devolatilization and then the char was refired into DTF at the same temperature under two different atmospheres O{sub 2}/N{sub 2} (typical combustion) and O{sub 2}/CO{sub 2} (oxy-combustion) with the same oxygen concentration. Coal injection was also performed under a higher oxygen concentration in both typical combustion and oxy-combustion atmospheres. The fuels tested comprised a petroleum coke and coals ranging in rank from high to low volatile bituminous, currently used for PCI injection. Specific surface areas, reactivity to CO{sub 2} and char petrography have been used to chars characterization. The morphology and appearance of the chars generated under oxy-fuel (O{sub 2}/CO{sub 2}) and conventional combustion (O{sub 2}/N{sub 2}) conditions with similar amount of oxygen were similar for each parent coal. Vitrinite-rich particles generated cenospheres with anisotropic optical texture increasing in size with increasing coal rank, whereas inertinite yielded a variety of morphologies and optical textures. The apparent reactivity to CO{sub 2} measured at high temperature (1000 C) tended to increase with burnout reflecting the operation under a regime controlled by internal diffusion in which surface area also increased. This may have a significant effect in the reactivity to CO{sub 2} of the chars inside the stack of the blast furnace

  13. The thermal stability and pyrolysis mechanism of boron-containing phenolic resins: The effect of phenyl borates on the char formation

    Science.gov (United States)

    Wang, Shujuan; Wang, Yong; Bian, Cheng; Zhong, Yuhu; Jing, Xinli

    2015-03-01

    Boron-containing phenolic resin (BPR) is a kind of the ablative resins with high-performance. Due to the lack of the exact knowledge concerning the pyrolysis mechanism of BPR, its development and application are greatly impeded. In the present paper, the chemical structure of the cured BPR and its structural evolution at high temperatures are investigated to clarify the reason for the high char yield of BPR. The results indicate that the high char yield of BPR is mainly attributed to the phenyl borates formed during curing, which can block parts of phenolic hydroxyl groups, and effectively inhibit their thermal decomposition reaction. Boron oxide is formed on the surface of carbonization products by the cleavage of O-C bonds from phenyl borates via pyrolysis, which avoids the release of volatile carbon dioxide and reduces the development of micro-structural defects of carbonization products. Introducing boron into PR improves the graphitization degree and graphite crystallites of carbonization products, which promotes the formation of a more ordered glassy carbon during pyrolysis. This study provides a new vision for the understanding of the high char yield of BPR, which makes it possible to develop a new ablative resin through molecular design.

  14. Practical considerations, column studies and natural organic material competition for fluoride removal with bone char and aluminum amended materials in the Main Ethiopian Rift Valley.

    Science.gov (United States)

    Brunson, Laura R; Sabatini, David A

    2014-08-01

    The fluoride removal capacities of three materials, bone char (BC), aluminum oxide coated bone char (ACBC) and aluminum oxide impregnated wood char (AIWC), along with activated alumina (AA) as a baseline material, were investigated in batch and column studies, including comparison between synthetic and natural groundwater. Results suggest that in all cases the laboratory column results exhibited higher fluoride removal efficiency than the field studies conducted in the Ethiopian Rift Valley. Further studies indicate that the reduced effectiveness in the field was likely due to a combination of the high pH of groundwater (8.2) and the presence of competing ions (sulfate). Batch studies testing potential competition from natural organic material (NOM) showed no statistical evidence of NOM competition with BC and minor evidence of competition with ACBC and AIWC. To provide evidence for using Rapid Scale Small Column Test (RSSCT) principles for BC two different column volume and particle sizes were used. The results indicate that RSSCT scaling equations, developed for activated carbon, are applicable for BC removal of fluoride. These results thus provide valuable insights for translating laboratory results of novel sorbents for mitigating fluoride tainted groundwater in the field. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Properties and Developments of Combustion and Gasification of Coal and Char in a CO2-Rich and Recycled Flue Gases Atmosphere by Rapid Heating

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    2012-01-01

    Full Text Available Combustion and gasification properties of pulverized coal and char have been investigated experimentally under the conditions of high temperature gradient of order 200°C·s−1 by a CO2 gas laser beam and CO2-rich atmospheres with 5% and 10% O2. The laser heating makes a more ideal experimental condition compared with previous studies with a TG-DTA, because it is able to minimize effects of coal oxidation and combustion by rapid heating process like radiative heat transfer condition. The experimental results indicated that coal weight reduction ratio to gases followed the Arrhenius equation with increasing coal temperature; further which were increased around 5% with adding H2O in CO2-rich atmosphere. In addition, coal-water mixtures with different water/coal mass ratio were used in order to investigate roles of water vapor in the process of coal gasification and combustion. Furthermore, char-water mixtures with different water/char mass ratio were also measured in order to discuss the generation ratio of CO/CO2, and specified that the source of Hydrocarbons is volatile matter from coal. Moreover, it was confirmed that generations of CO and Hydrocarbons gases are mainly dependent on coal temperature and O2 concentration, and they are stimulated at temperature over 1000°C in the CO2-rich atmosphere.

  16. Sorption of apolar and polar organic contaminants by waste tire rubber and its chars in single- and bi-solute systems.

    Science.gov (United States)

    Lian, Fei; Huang, Fang; Chen, Wei; Xing, Baoshan; Zhu, Lingyan

    2011-04-01

    Single- and bi-solute sorption of organic compounds [1,3-dichlorbenzene (DCB), 1,3-dinitrobenzene (DNB) and 2,4-dichlorophenol (DCP)] on ground tire rubber and its chars was studied. The chars were prepared by pyrolyzing tire rubber at different temperatures (200-800 °C). Their surface area, aromaticity and hydrophobicity increase greatly with pyrolytic temperature, and the polymeric phase is partly converted into a condensed phase. The sorption of DNB and DCP increases with pyrolytic temperature and is characterized by a transition from a partition dominant to an adsorption dominant process. However, the sorption of DCB linearly decreases with the pyrolytic temperature. The enhanced adsorption of DNB and DCP on carbonized phase is primarily attributed to nonhydrophobic interactions such as π-π electron-donor-acceptor interactions and/or H bonding. The higher partition of DCB to polymeric phase is attributed to its high hydrophobicity. Competitive sorption between DCB and DCP on the tire chars is highly dependent on dissociation of the latter. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Co-pyrolysis behavior of microalgae biomass and low-quality coal: Products distributions, char-surface morphology, and synergistic effects.

    Science.gov (United States)

    Wu, Zhiqiang; Yang, Wangcai; Li, Yaowu; Yang, Bolun

    2018-05-01

    In this work, the distributions and releasing properties of the primary volatile products during co-pyrolysis of low-rank coal and green algae (GA) has been studied using fixed-bed reactor with online mass spectrometry. Surface morphology of the char was described quantitatively by SEM combined with fractal theory. Different forms of synergistic effects existed from both the yields of products and composition of the main gaseous products. Positive synergistic effects from tar yield were observed under 25% of GA from 600 to 850 °C, indicating GA promoted the formation of tar. Opposite synergistic effects on the content of H 2 and CO were gained when the mass ratio of GA was 50%. The fractal dimensions of co-pyrolysis char were less than the calculated values except under 650 °C, which meant the GA promoted the homogeneity of char surface. This work could provide essential data for proper operation parameters selecting for co-pyrolysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Preliminary investigation on the production of fuels and bio-char from Chlamydomonas reinhardtii biomass residue after bio-hydrogen production.

    Science.gov (United States)

    Torri, Cristian; Samorì, Chiara; Adamiano, Alessio; Fabbri, Daniele; Faraloni, Cecilia; Torzillo, Giuseppe

    2011-09-01

    The aim of this work was to investigate the potential conversion of Chlamydomonas reinhardtii biomass harvested after hydrogen production. The spent algal biomass was converted into nitrogen-rich bio-char, biodiesel and pyrolysis oil (bio-oil). The yield of lipids (algal oil), obtained by solvent extraction, was 15 ± 2% w/w(dry-biomass). This oil was converted into biodiesel with a 8.7 ± 1% w/w(dry-biomass) yield. The extraction residue was pyrolysed in a fixed bed reactor at 350 °C obtaining bio-char as the principal fraction (44 ± 1% w/w(dry-biomass)) and 28 ± 2% w/w(dry-biomass) of bio-oil. Pyrolysis fractions were characterized by elemental analysis, while the chemical composition of bio-oil was fully characterized by GC-MS, using various derivatization techniques. Energy outputs resulting from this approach were distributed in hydrogen (40%), biodiesel (12%) and pyrolysis fractions (48%), whereas bio-char was the largest fraction in terms of mass. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Pyrolysis of waste animal fats in a fixed-bed reactor: production and characterization of bio-oil and bio-char.

    Science.gov (United States)

    Ben Hassen-Trabelsi, A; Kraiem, T; Naoui, S; Belayouni, H

    2014-01-01

    Several animal (lamb, poultry and swine) fatty wastes were pyrolyzed under nitrogen, in a laboratory scale fixed-bed reactor and the main products (liquid bio-oil, solid bio-char and syngas) were obtained. The purpose of this study is to produce and characterize bio-oil and bio-char obtained from pyrolysis of animal fatty wastes. The maximum production of bio-oil was achieved at a pyrolysis temperature of 500 °C and a heating rate of 5 °C/min. The chemical (GC-MS analyses) and spectroscopic analyses (FTIR analyses) of bio-oil showed that it is a complex mixture consisting of different classes of organic compounds, i.e., hydrocarbons (alkanes, alkenes, cyclic compounds...etc.), carboxylic acids, aldehydes, ketones, esters,...etc. According to fuel properties, produced bio-oils showed good properties, suitable for its use as an engine fuel or as a potential source for synthetic fuels and chemical feedstock. Obtained bio-chars had low carbon content and high ash content which make them unattractive for as renewable source energy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Decontamination of arsenic(V)-contained liquid phase utilizing Fe3O4/bone char nanocomposite encapsulated in chitosan biopolymer.

    Science.gov (United States)

    Darvishi Cheshmeh Soltani, Reza; Safari, Mahdi; Maleki, Afshin; Rezaee, Reza; Shahmoradi, Behzad; Shahmohammadi, Siran; Ghahramani, Esmail

    2017-06-01

    The application of a novel nanocomposite synthesized through the combination of Fe3O4 nanoparticles and bone char particles for the adsorption of As(V) ions in the aquatic medium was investigated. As-prepared nanocomposite was immobilized by using chitosan biopolymer. The characterization of the nanocomposite was performed via SEM, XRD, FT-IR, and BET together with the determination of zero-point charge of the adsorbent surface. As results, the obtained experimental data were fitted well with pseudo-first-order kinetic model (R(2) = 0.997) and Langmuir isotherm model (R(2) = 0.990) with the maximum adsorption capacity of about 112 μg/g. Increasing the dosage of nanocomposite and initial solute concentration led to increasing the adsorption capacity of As(V) ions, while decreasing the solution temperature resulted in the enhanced adsorption process. According to the results of thermodynamic study, the adsorption of As(V) ions onto the nanocomposite was spontaneous and exothermic in nature.

  1. Adsorption of Cu(2+) and methyl orange from aqueous solutions by activated carbons of corncob-derived char wastes.

    Science.gov (United States)

    Hou, Xiao-Xu; Deng, Qing-Fang; Ren, Tie-Zhen; Yuan, Zhong-Yong

    2013-12-01

    Corncob-derived char wastes (CCW) obtained from biomass conversion to syngas production through corncob steam gasification, which were often discarded, were utilized for preparation of activated carbon by calcination, and KOH and HNO3 activation treatments, on the view of environment protection and waste recycling. Their adsorption performance in the removal of heavy metal ions and dye molecules from wastewater was evaluated by using Cu(2+) and methyl orange (MO) as the model pollutant. The surface and structure characteristics of the CCW-based activated carbons (CACs) were investigated by N2 adsorption, CO2 adsorption, FT-IR, and He-TPD. The adsorption capacity varied with the activation methods of CACs and different initial solution concentrations, indicating that the adsorption behavior was influenced by not only the surface area and porosity but also the oxygen functional groups on the surface of the CACs. The equilibrium adsorption data were analyzed with the Langmuir, Freundlich, and Temkin isotherm models, and the adsorption kinetics was evaluated by the pseudo-first-order and pseudo-second-order models.

  2. Interaction of molten salts with a semi-anthracite char at 743 K. Influence on the gasification in air

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Serrano, V.; Alfaro-Dominguez, M.; Higes-Rolando, F.J. [Universidad de Extremadura, Badajoz (Spain). Dept. de Quimica Inorganica; Martin-Aranda, M.; Rojas-Cervantes, M.L.; Lopez-Peinado, A.J. [Universidad Nacional de Educacion a Distancia (UNED), Madrid (Spain). Dept. de Quimica Inorganica

    1997-12-31

    The treatments of a semi-anthracite char (AC) with molten salts followed by washing of the intermediate products with distilled water as a rule produce an increase in the surface area of micropores (S{sub mi}) and in the mean equivalent pore diameter (MEPD), which is greater for AC-MgO. The variation of MEPD is only slight for AC-CaO and AC-CoO. The reactivity of the carbon in air at 823 K enhances for a number of samples but especially for AC-CaO and AC-MgO. Washing with HCl generally results in a small increase in S{sub mi} and in a more uniform MEPD. The reactivity of the carbon decreases for most samples including AN and AC. This suggests that mineral components of the starting materials and chemical species present in distilled waterwashed samples (i.e. metal oxides in excess and reaction products of molten salts with the mineral fraction of AC) are catalytically active and that their removal from such samples occurs by washing with HCl. The presence of catalytic species seems to be greater for AC-MgO and AC-CaO than for the other samples. (orig.)

  3. NOx removal by low-cost char pellets: Factors influencing the activity and selectivity towards NOx reduction

    Energy Technology Data Exchange (ETDEWEB)

    Jose Maria Soriano-Mora; Agustin Bueno-Lopez; Avelina Garcia-Garcia; Ron E. Perry; Colin E. Snape [University of Alicante, Alicante (Spain). MCMA Group, Department of Inorganic Chemistry

    2007-05-15

    The activity of potassium-containing char pellets prepared from different low-cost carbon precursors towards NOx reduction in an oxygen-rich environment has been investigated by isothermal reactions at 325{sup o}C. From the overall data, it can be asserted that high potassium content is a key factor in allowing carbon-based pellets to achieve better NOx reduction capacities whilst exhibiting higher selectivity to NOx reduction and inhibiting carbon burn-off, but the intrinsic characteristics of the carbon precursor must also be taken into account (mineral matter content, carbon nature...). Having chosen the most appropriate formulation for pellet preparation (high potassium content and suitable carbon precursor, a metallurgical coke), the 3HT-C pellets demonstrated the most promise for consideration for NOx removal. This sample, when tested as a packed bed of pellets at 325{sup o}C, gave more moderate and very constant NOx reduction rates in combination with very high selectivity towards NOx. On the other hand, when tested at 400-450{sup o}C, very high and constant NOx reduction rates were achieved, with decreased but still acceptable selectivity. Reaction data from a lifetime test were not significantly worse than those from a 2 h reaction, which is very encouraging. Neither was sample efficiency compromised in the lifetime test, in which only 18% (maximum) of oxygen was consumed compared with 84.1% (maximum) NOx converted. 21 refs., 6 figs., 5 tabs.

  4. Bio-oil and bio-char from low temperature pyrolysis of spent grains using activated alumina.

    Science.gov (United States)

    Sanna, Aimaro; Li, Sujing; Linforth, Rob; Smart, Katherine A; Andrésen, John M

    2011-11-01

    The pyrolysis of wheat and barley spent grains resulting from bio-ethanol and beer production respectively was investigated at temperatures between 460 and 540 °C using an activated alumina bed. The results showed that the bio-oil yield and quality depend principally on the applied temperature where pyrolysis at 460 °C leaves a bio-oil with lower nitrogen content in comparison with the original spent grains and low oxygen content. The viscosity profile of the spent grains indicated that activated alumina could promote liquefaction and prevent charring of the structure between 400 and 460 °C. The biochar contains about 10-12% of original carbon and 13-20% of starting nitrogen resulting very attractive as a soil amendment and for carbon sequestration. Overall, value can be added to the spent grains opening a new market in bio-fuel production without the needs of external energy. The bio-oil from spent grains could meet about 9% of the renewable obligation in the UK. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Comparison of Pb(II) immobilized by bone char meal and phosphate rock: characterization and kinetic study.

    Science.gov (United States)

    Chen, Shibao; Ma, Yibing; Chen, Li; Wang, Liqun; Guo, Haitao

    2010-01-01

    Adsorption isotherms and kinetics of aqueous Pb(II) by bone char meal (BM) and phosphate rock (PR) were investigated using batch experiments. Pb removal was characterized and effects of pH and reaction time on Pb removal efficiency by BM/PR were also investigated. Results indicated that Pb removal efficiency by BM and PR is mainly controlled by dissolution of phosphatic components associated with apatite, followed by subsequent precipitation of geochemically stable pyromorphite [Pb10(PO4)6(OH,Cl)2]. Sorption kinetics results indicated that Pb sorption onto BM or PR was generally biphasic, with initially fast reactions followed by slow and continuous reactions. Pb removal efficiency by BM and PR increased with increasing pH except at a pH higher than 6.15. Sorption isotherms showed that BM has a much higher Pb removal rate than PR in solution; the greater capability of BM than of PR to remove aqueous Pb indicates its potential as another promising way to remediate Pb-contaminated media.

  6. SiteChar. Characterisation of European CO2 storage. Deliverable D8.1. Qualitative and quantitative social site characterisations

    Energy Technology Data Exchange (ETDEWEB)

    Brunsting, S.; Pol, M.; Paukovic, M. [ECN Policy Studies, Energy research Centre of the Netherlands ECN, Amsterdam (Netherlands); Kaiser, M.; Zimmer, R. [Unabhaengiges Institut fuer Umweltfragen UfU, Berlin (Germany); Shackley, S.; Mabon, L. [Scottish Carbon Capture and Storage SCCS, Edinburg, Scotland (United Kingdom); Hepplewhite, F.; Loveridge, R. [Energy Markets Unit, Scottish Government, Edinburg, Scotland (United Kingdom); Mazurowski, M.; Polak-Osiniak, D. [Polish Oil and Gas Company PGNiG, Warszawa (Poland); Rybicki, C. [AGH University of Science and Technology, Krakow (Poland)

    2012-10-15

    At local level, public support has proven crucial to the implementation of CO2 capture and storage (CCS) demonstration projects. Whereas no method exists to guarantee public acceptability of any project, a constructive stakeholder engagement process does increase the likelihood thereof. Social site characterisation can be used as an instrument to explore, plan and evaluate a process of active and constructive local stakeholder engagement in a prospective CCS project as a parallel activity to technical site characterisation. It roughly consists of a formative research phase to get acquainted with the area followed by a series of public information and engagement activities. This deliverable presents results from the first phase for the social site characterisations of a prospective CCS site in Poland (onshore) and the UK (offshore), using qualitative as well as quantitative research methods, as a first step to planning of local public engagement activities and evaluation of these activities that will be undertaken by this consortium at both sites in the near future. Although the term social site characterisation actually refers to the entire process of formative research and subsequent public outreach, and hence to the complete package of awareness work undertaken as part of SiteChar, in the present deliverable the term only refers to the formative research activities as undertaken up to now and as described in this deliverable. The qualitative part of the social site characterisation consisted of (1) a description of relevant social site characteristics such as local history; (2) interviews with relevant local stakeholders; (3) a media analysis of local newspapers. The quantitative part of the social site characterisation consisted of surveys using representative samples to characterise the local population in terms of awareness, knowledge and perceptions of CCS, felt involvement in decision making, extent of local activism, level of trust in representatives and

  7. Adding the combination of CNTs and MoS{sub 2} into halogen-free flame retarding TPEE with enhanced the anti-dripping behavior and char forming properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yuhua; Li, Maolin; Zhang, Luchong; Zhang, Xuewei; Zhu, Songwei; Wu, Wei, E-mail: wuwei@ecust.edu.cn

    2015-08-10

    Highlights: • Introduction the combination of the CNTs and MoS{sub 2} into P–N flame retarding TPEE. • Binary synergists for P–N flame retardants in TPEE. • Increase of char yield and form the stable carbonaceous char. - Abstract: In this paper, the nanocomposites thermoplastic polyester-ether elastomer (TPEE) with phosphorus–nitrogen (P–N) flame retardants, carbon nanotubes (CNTs) and molybdenum disulfide (MoS{sub 2}) was prepared by melt blending. TPEE containing P–N flame retardant, CNTs and MoS{sub 2} achieved UL94 V-0 rating due to the better barrier effect of the special structure. The structure was supported by the result of rheological properties. The thermal stability was studied by thermal gravimetric analysis (TGA) and char residue characterization was investigated by SEM–EDX measurements. The results demonstrated that the combination of CNTs and MoS{sub 2} results in the increase of char yield and the formation of the thermally stable char which can effectively prevent in the dripping behavior during the burning process.

  8. Studying ancient crop provenance: implications from δ(13)C and δ(15)N values of charred barley in a Middle Bronze Age silo at Ebla(NW Syria).

    Science.gov (United States)

    Fiorentino, Girolamo; Caracuta, Valentina; Casiello, Grazia; Longobardi, Francesco; Sacco, Antonio

    2012-02-15

    The discovery of a storeroom full of barley and other cereals (L.9512) in the proto-historic site of Ebla has provided a unique opportunity to study the centralized storage system of the early city-state from a different perspective. Epigraphic evidence available within the site reveals a complex system of taxation which included gathering grain tributes from satellite sites and redistributing semi-finished products such as flour. In this paper, we intend to explore the possibilities of a combined approach to studying the storage system, based on estimated barley grain volumes and δ(13)C-δ(15)N analyses. This approach is used to distinguish between grain from different harvesting sites and to identify any grain cultivated using special agricultural practices (e.g. manuring or irrigation). The basic assumption for this kind of analysis is that the growth-site conditions, natural or anthropogenic, of harvested cereals are reflected in their grain size and δ(13)C-δ(15)N values. Since the remains found in the storeroom were charred, the first task was to evaluate the effect of carbonization on the δ(13)C-δ(15)N and the size of the grains. Thus, the effect of charring was tested on modern samples of Syrian barley landraces. Once it had been ascertained that fresh grains reduced to charred remains retain their original biometric and isotopic traits, the ancient material was examined. Thirteen groups were identified, each characterized by a specific average volume and specific carbon and nitrogen values. The analysis revealed that what had first appeared to be a homogeneous concentration of grain was in fact an assemblage of barley harvested from different sites. Copyright © 2012 John Wiley & Sons, Ltd.

  9. The Effects of a Macromolecular Charring Agent with Gas Phase and Condense Phase Synergistic Flame Retardant Capability on the Properties of PP/IFR Composites.

    Science.gov (United States)

    Chen, Hongda; Wang, Jihui; Ni, Aiqing; Ding, Anxin; Han, Xia; Sun, Ziheng

    2018-01-11

    In order to improve the efficiency of intumescent flame retardants (IFRs), a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine) (PETAT) with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP) in combination with ammonium polyphosphate (APP) via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR), and ¹H nuclear magnetic resonance (NMR) spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) and thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR). The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI) values before and after soaking, underwritten laboratory-94 (UL-94) vertical burning test, cone calorimetric test (CCT), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS), and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR), total heat release (THR), and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame

  10. Th Application of Dose-Response Models to Determine the Median Effctive Adsorbent Bone Char Dose to Remove Fluoride From Drinking Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    S.Zebarjadi

    2016-11-01

    Full Text Available Introduction: In studies of the adsorption of pollutants onto diffrent adsorbents, determining the adsorbent dose of the most important characteristics must be considered. Th aim of the study was the determination and modeling of dose-response bone char floride removal from aqueous solutions and comparison of the adsorption isotherm models with dose-response models from the perspective of adsorption. Methods: In this experimental study, bone char was prepared by using an electric furnace at 450˚C in two hours. Sorting the adsorbent was conducted by standard sieve ASTM in the range of 35-18 meshes and its characteristics were determined with conventional methods. Th concentration of floride was measured according to the recommendation of manufacturer HACH( with Dr5000- of regent floride. Dose-response models were fi to the data and parameters were estimated. Based on the quality of finess indicators, the adsorption isotherm models were compared with dose-response models. Analysis of the data in this study was performed using the R softare version 3.1.2 and stats package. Results: Fit indexes AIC and R2( showed that the most appropriate model for the data in pH= 10, concentration = 10 and pH = 7, concentration = 20 was the Emax model and in pH = 7, concentration = 10 and pH = 7, concentration = 15 the quadratic model. According to these models, the median of effctive dose on bone char at removal of floride was determined 0.11 g in concentration of 10 mg/L and pH = 10. Th maximum effctive dose was determined 1.25 g in concentration of 20 mg/L and pH = 7. Th index AIC( showed that quadratic dose-response models bettr fi to adsorption data than adsorption isotherm models. Conclusions: Th median and maximum effctive doses of bone char at removal of floride were estimated by statistical models more accurately. In addition, determining the goal dose was performed using modeling method, which was more economic than repeated testing, and the performance

  11. The Effects of a Macromolecular Charring Agent with Gas Phase and Condense Phase Synergistic Flame Retardant Capability on the Properties of PP/IFR Composites

    Science.gov (United States)

    Chen, Hongda; Wang, Jihui; Ding, Anxin; Han, Xia; Sun, Ziheng

    2018-01-01

    In order to improve the efficiency of intumescent flame retardants (IFRs), a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine) (PETAT) with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP) in combination with ammonium polyphosphate (APP) via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR), and 1H nuclear magnetic resonance (NMR) spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) and thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR). The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI) values before and after soaking, underwritten laboratory-94 (UL-94) vertical burning test, cone calorimetric test (CCT), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS), and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR), total heat release (THR), and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame

  12. Linking charring temperature and wood source to the structure and degradation rates of pyrogenic organic matter in soil

    Science.gov (United States)

    Hatton, P.; Dastmalchi, K.; Chatterjee, S.; Auclerc, A.; Le Moine, J.; Filley, T. R.; Nadelhoffer, K. J.; Stark, R.; Bird, J. A.

    2013-12-01

    Fire is a major controller of forest C cycling by releasing CO2 to the atmosphere and by contributing pyrogenic organic matter (PyOM or biochar) to soils. Recent studies have shown that much of fire-derived PyOM may turn over in soils at century time scales. Two likely controllers of the chemical structure of PyOM and its resulting decay rate are pyrolysis temperature and the source biomass. However, we know little of how these two factors determine the chemical structure and bioreactivity of the resulting PyOM. To gain further insight into controls on the structure and fate of PyOM, we examined two species of dual-labeled (13C/15N), wood-based PyOM (Pinus banksiana and Acer rubrum) made with 5 pyrolysis temperatures (0, 200, 300, 450, 600 °C) using solid state nuclear magnetic resonance, isotopic and elemental composition (C, H, O, and N), and differential scanning calorimetry. In addition, we are investigating the fate of a subset of these PyOM materials applied to forest soils in a long-term field study located at the University of Michigan Biological Station in Pellston, MI, USA. We will present data of the loss of PyOM C as CO2 and DOC during the first year in situ. We found complementary lines of evidence for a facile removal of cellulose and hemicellulose and a progressive alteration of nitrogenous moieties across the charring gradient for wood-derived PyOM of both tree species as temperature was increased from 0 to 600 °C. Our NMR results show a significant species by pyrolysis temperature interaction on PyOM chemical structure with considerably less condensation for Acer- than Pinus-derived PyOM at 300 °C. In the first year after addition to soil, Acer-derived PyOM pyrolyzed at 450 °C mineralized faster than Pinus-derived PyOM pyrolyzed at 450 °C. Increasing pyrolysis temperatures for Pinus-derived PyOM also resulted in slower CO2 mineralization rates during the first year of field decay. These results relate pyrolysis temperature to the resulting Py

  13. Hydrogen-rich gas production by steam gasification of char from biomass fast pyrolysis in a fixed-bed reactor: influence of temperature and steam on hydrogen yield and syngas composition.

    Science.gov (United States)

    Yan, Feng; Luo, Si-yi; Hu, Zhi-quan; Xiao, Bo; Cheng, Gong

    2010-07-01

    Steam gasification experiments of biomass char were carried out in a fixed-bed reactor. The experiments were completed at bed temperature of 600-850 degrees C, a steam flow rate of 0-0.357 g/min/g of biomass char, and a reaction time of 15min. The aim of this study is to determine the effects of bed temperature and steam flow rate on syngas yield and its compositions. The results showed that both high gasification temperature and introduction of proper steam led to higher yield of dry gas and higher carbon conversion efficiency. However, excessive steam reduced gas yield and carbon conversion efficiency. The maximum dry gas yield was obtained at the gasification temperature of 850 degrees C and steam flow rate of 0.165 g/min/g biomass char. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  14. Influence of reaction conditions and the char separation system on the production of bio-oil from radiata pine sawdust by fast pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Ju; Park, Young-Kwon; Kim, Joo Sik [Faculty of Environmental Engineering, University of Seoul, 90 Jeonnong-Dong, Dondaemun-Gu, Seoul 130-743 (Korea)

    2008-08-15

    Radiata pine sawdust was pyrolyzed in a bubbling fluidized bed equipped with a char separation system. The influence of the reaction conditions on the production of bio-oil was investigated through the establishment of mass balance, and the examination of the products' chemical and physical characteristics. The optimal reaction temperature for the production of bio-oil was between 673 and 723 K, and the yield was above 50 wt.% of the product. An optimal feed size also existed. In a particle with a size that was less than 0.3 mm, the bio-oil yield decreased due to overheating, which led to gas formation. A higher flow rate and feeding rate were found to be more effective for the production of bio-oil, but did not significantly affect it. The main compounds of bio-oil were phenolics, including cresol, guaiacol, eugenol, benzendiol and their derivatives, ketones, and aldehydes. In addition, high-quality bio-oils, which contained less than 0.005 wt.% of solid, no ash and low concentrations of alkali and alkaline earth metals, were produced due to the char removal system. (author)

  15. Slash-and-char: An ancient agricultural technique holds new promise for management of soils contaminated by Cd, Pb and Zn.

    Science.gov (United States)

    Niu, Li-Qin; Jia, Pu; Li, Shao-Peng; Kuang, Jia-Liang; He, Xiao-Xin; Zhou, Wen-Hua; Liao, Bin; Shu, Wen-Sheng; Li, Jin-Tian

    2015-10-01

    Heavy metal contamination of agricultural soils is of worldwide concern. Unfortunately, there are currently no efficient and sustainable approaches for addressing this concern. In this study, we conducted a field experiment in which an agricultural soil highly contaminated by cadmium (Cd), lead (Pb) and zinc (Zn) was treated on-site by an ancient agricultural technique, 'slash-and-char', that was able to convert the biomass feedstock (rice straw) into biochar in only one day. We found evidence that in comparison to the untreated soil, the treated soil was associated with decreased bioavailability of the heavy metals and increased vegetable yields. Most importantly, the treatment was also coupled with dramatic reductions in concentrations of the heavy metals in vegetables, which made it possible to produce safe crops in this highly contaminated soil. Collectively, our results support the idea that slash-and-char offers new promise for management of soils contaminated by Cd, Pb and Zn. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Risk Assessment-Led Characterisation of the SiteChar UK North Sea Site for the Geological Storage of CO2

    Directory of Open Access Journals (Sweden)

    Akhurst Maxine

    2015-04-01

    Full Text Available Risk assessment-led characterisation of a site for the geological storage of CO2 in the UK northern North Sea was performed for the EU SiteChar research project as one of a portfolio of sites. Implementation and testing of the SiteChar project site characterisation workflow has produced a ‘dry-run’ storage permit application that is compliant with regulatory requirements. A site suitable for commercial-scale storage was characterised, compatible with current and future industrial carbon dioxide (CO2 sources in the northern UK. Pre-characterisation of the site, based on existing information acquired during hydrocarbon exploration and production, has been achieved from publicly available data. The project concept is to store captured CO2 at a rate of 5 Mt per year for 20 years in the Blake Oil Field and surrounding Captain Sandstone saline aquifer. This commercial-scale storage of 100 Mt CO2 can be achieved through a storage scenario combining injection of CO2 into the oil field and concurrent water production down-dip of the field. There would be no encroachment of supercritical phase CO2 for more than two kilometres beyond the field boundary and no adverse influence on operating hydrocarbon fields provided there is pressure management. Components of a storage permit application for the site are presented, developed as far as possible within a research project. Characterisation and technical investigations were guided by an initial assessment of perceived risks to the prospective site and a need to provide the information required for the storage permit application. The emphasis throughout was to reduce risks and uncertainty on the subsurface containment of stored CO2, particularly with respect to site technical performance, monitoring and regulatory issues, and effects on other resources. The results of selected risk assessment-led site characterisation investigations and the subsequent risk reassessments are described together with their

  17. Large deviations

    CERN Document Server

    Varadhan, S R S

    2016-01-01

    The theory of large deviations deals with rates at which probabilities of certain events decay as a natural parameter in the problem varies. This book, which is based on a graduate course on large deviations at the Courant Institute, focuses on three concrete sets of examples: (i) diffusions with small noise and the exit problem, (ii) large time behavior of Markov processes and their connection to the Feynman-Kac formula and the related large deviation behavior of the number of distinct sites visited by a random walk, and (iii) interacting particle systems, their scaling limits, and large deviations from their expected limits. For the most part the examples are worked out in detail, and in the process the subject of large deviations is developed. The book will give the reader a flavor of how large deviation theory can help in problems that are not posed directly in terms of large deviations. The reader is assumed to have some familiarity with probability, Markov processes, and interacting particle systems.

  18. A first step towards identification of tannin-derived black carbon: Conventional pyrolysis (Py–GC–MS) and thermally assisted hydrolysis and methylation (THM–GC–MS) of charred condensed tannins

    NARCIS (Netherlands)

    Kaal, J.; Nierop, K.G.J.; Kraal, P.; Preston, C.M.

    2012-01-01

    Tannins account for a significant proportion of plant biomass and are likely to contribute to the residues formed by incomplete biomass combustion (black carbon, BC). Nonetheless, the molecular properties of thermally modified tannins have not been investigated in laboratory charring experiments. We

  19. Large deviations

    CERN Document Server

    Hollander, Frank den

    2008-01-01

    This book is an introduction to the theory and applications of large deviations, a branch of probability theory that describes the probability of rare events in terms of variational problems. By focusing the theory, in Part A of the book, on random sequences, the author succeeds in conveying the main ideas behind large deviations without a need for technicalities, thus providing a concise and accessible entry to this challenging and captivating subject. The selection of modern applications, described in Part B of the book, offers a good sample of what large deviation theory is able to achieve

  20. Comprehensive model for predicting elemental composition of coal pyrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Ricahrds, Andrew P. [Brigham Young Univ., Provo, UT (United States); Shutt, Tim [Brigham Young Univ., Provo, UT (United States); Fletcher, Thomas H. [Brigham Young Univ., Provo, UT (United States)

    2017-04-23

    Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumption is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases.

  1. Pisum & Ervilia Tetovac: Made in Early Iron Age Leskovac, Part one: Two charred pulse crop storages of the fortified hill fort settlement Hissar in Leskovac, South Serbia

    Directory of Open Access Journals (Sweden)

    Medović Aleksandar

    2011-01-01

    Full Text Available A lucky find of 2,572 charred pea (Pisum sativum L seeds in a single archaeobotanical sample from the hill fort settlement Hissar near Leskovac represents a unique example in Bronze / Iron Age research in South East Europe. Another mass storage of bitter vetch (Vicia ervilia (L Willd from the same site and period (Brnjica cultural group, beginning of the Iron Age in the Morava valley confirms a long tradition of the city of Leskovac region as a pulse crop production centre in modern Serbia. Both pulse storages were almost pure with small amount of admixture from other crops mainly cereals, other pulses, such as lentil (Lens culinaris Medik and broad bean (Vicia faba L, and oil/fibre plants. Both pulses were cultivated as main crops and were stored separately.

  2. Addressing catch mechanisms in gillnets improves modeling of selectivity and estimates of mortality rates: a case study using survey data on an endangered stock of Arctic char

    DEFF Research Database (Denmark)

    Jonsson, T.; Setzer, M.; Pope, John George

    2013-01-01

    Estimation of fish stock size distributions from survey data requires knowledge about gear selectivity. However, selectivity models rest on assumptions that seldom are analyzed. Departures from these can lead to misinterpretations and biased management recommendations. Here, we use survey data...... on great Arctic char (Salvelinus umbla) to analyze how correcting for entanglement of fish and nonisometric growth might improve estimates of selectivity curves, and subsequently estimates of size distribution and age-specific mortality. Initial selectivity curves, using the entire data set, were wide...... and asymmetric, with poor model fits. Removing potentially nonmeshed fish had the greatest positive effect on model fit, resulting in much narrower and less asymmetric selection curves, while attempting to take nonisometric growth into account, by using girth rather than length, improved model fit...

  3. Large deviations

    CERN Document Server

    Deuschel, Jean-Dominique; Deuschel, Jean-Dominique

    2001-01-01

    This is the second printing of the book first published in 1988. The first four chapters of the volume are based on lectures given by Stroock at MIT in 1987. They form an introduction to the basic ideas of the theory of large deviations and make a suitable package on which to base a semester-length course for advanced graduate students with a strong background in analysis and some probability theory. A large selection of exercises presents important material and many applications. The last two chapters present various non-uniform results (Chapter 5) and outline the analytic approach that allow

  4. Albert Camus, René Char: fonction du paysage méditerranéen dans l'identité de l'artiste et de l'écrivain au XXeme siècle

    OpenAIRE

    Nathalie Pacchiani

    2013-01-01

    Il arrive parfois qu’une œuvre soit un microcosme de la problématique existentielle d’un écrivain. Il en est ainsi de L’exil et le royaume ou Noces d’Albert Camus et Feuillets d’Hypnos de René Char. Ces œuvres, en effet, illustrent mieux que tout autre le rapport particulier qu’entretenaient les deux auteurs avec les éléments naturels et qui fut le fondement même de leur amitié. Si Albert Camus et René Char demeuraient liés par une vision commune et fondamentale de la place de l’homme dans le...

  5. Development of a high-performance coal-fired power generating system with pyrolysis gas and char-fired high temperature furnace (HITAF)

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    A concept for an advanced coal-fired combined-cycle power generating system is currently being developed. The first phase of this three-phase program consists of conducting the necessary research and development to define the system, evaluate the economic and technical feasibility of the concept, and prepare an R D plan to develop the concept further. Foster Wheeler Development Corporation is leading a team ofcompanies involved in this effort. The system proposed to meet these goals is a combined-cycle system where air for a gas turbine is indirectly heated to approximately 1800[degrees]F in furnaces fired with cool-derived fuels and then directly heated in a natural-gas-fired combustor up to about 2400[degrees]F. The system is based on a pyrolyzing process that converts the coal into a low-Btu fuel gas and char. The fuelgas is a relatively clean fuel, and it is fired to heat tube surfaces that are susceptible to corrosion and problems from ash deposition. In particular, the high-temperature air heater tubes, which will need tobe a ceramic material, will be located in a separate furnace or region of a furnace that is exposed to combustion products from the low-Btu fuel gas only. A simplified process flow diagram is shown.

  6. Comparative studies on adsorptive removal of heavy metal ions by biosorbent, bio-char and activated carbon obtained from low cost agro-residue.

    Science.gov (United States)

    Kırbıyık, Çisem; Pütün, Ayşe Eren; Pütün, Ersan

    2016-01-01

    In this study, Fe(III) and Cr(III) metal ion adsorption processes were carried out with three adsorbents in batch experiments and their adsorption performance was compared. These adsorbents were sesame stalk without pretreatment, bio-char derived from thermal decomposition of biomass, and activated carbon which was obtained from chemical activation of biomass. Scanning electron microscopy and Fourier transform-infrared techniques were used for characterization of adsorbents. The optimum conditions for the adsorption process were obtained by observing the influences of solution pH, adsorbent dosage, initial solution concentration, contact time and temperature. The optimum adsorption efficiencies were determined at pH 2.8 and pH 4.0 for Fe(III) and Cr(III) metal ion solutions, respectively. The experimental data were modelled by different isotherm models and the equilibriums were well described by the Langmuir adsorption isotherm model. The pseudo-first-order, pseudo-second-order kinetic, intra-particle diffusion and Elovich models were applied to analyze the kinetic data and to evaluate rate constants. The pseudo-second-order kinetic model gave a better fit than the others. The thermodynamic parameters, such as Gibbs free energy change ΔG°, standard enthalpy change ΔH° and standard entropy change ΔS° were evaluated. The thermodynamic study showed the adsorption was a spontaneous endothermic process.

  7. Estimativa da disponibilidade de forragem do bioma Campos Sulinos a partir de dados radiométricos orbitais: parametrização do submodelo espectral Forecast the available forage of natural pastures of Campos Sulinos biome using satellite spectral data: parameterization for the spectral submodel

    Directory of Open Access Journals (Sweden)

    Eliana Lima da Fonseca

    2007-12-01

    Full Text Available Este trabalho apresenta a parametrização do submodelo espectral do modelo JONG, um modelo agrometeorológico-espectral para a previsão da disponibilidade de forragem das pastagens naturais do bioma Campos Sulinos. A parametrização foi feita testando-se a capacidade de diferentes variáveis espectrais obtidas a partir de imagens do sensor ETM+/Landsat 7 representando a disponibilidade de forragem em diferentes fases do ciclo fenológico da vegetação campestre natural do bioma Campos Sulinos. Verificou-se que as variáveis Wetness e reflectância da banda ETM+7/Landsat 7 representam o status inicial da vegetação de forma eficiente, mas não tiveram sensibilidade suficiente para eliminar os efeitos do tipo de solo na resposta espectral da vegetação.This research presents the parameterization for the spectral submodel of JONG model, an agrometeorologic-spectral model to forecast the available forage of natural pastures of Campos Sulinos biome. Tthe capacity of different spectral variables, gotten from images of the sensor ETM+/Landsat 7, to represent the forage availability in different phases of its fenologic cycle was realized. The Wetness variable and reflectance of the band ETM+7/Landsat 7 represent the initial status of vegetation of efficient form was verified, however had no sensitivity enough to eliminate the effect of soil type in the spectral response of the vegetation.

  8. Photocatalytic reduction of Cr(VI) by char/TiO2 composite photocatalyst: optimization and modeling using the response surface methodology (RSM).

    Science.gov (United States)

    Antonopoulou, M; Chondrodimou, I; Bairamis, F; Giannakas, A; Konstantinou, I

    2017-01-01

    The photocatalytic reduction of Cr(VI) using pyrolytic char/TiO2 (PC/TiO2) composite catalyst under simulated solar irradiation was studied. Response surface methodology (RSM) and experimental design were used for modeling the removal kinetics and for the optimization of operational parameters. RSM was developed by considering a central composite design with four input variable, i.e. catalyst concentration, initial concentration of Cr(VI), pH, and % (v/v) methanol concentration for assessing individual and interactive effects. A quadratic model was established as a functional relationship between four independent variables and the removal efficiency of Cr(VI). It was found that all selected variables have significant effect on Cr(VI) removal efficiency; however, the pH, the % concentration of methanol, and their interaction exhibited the major effects. Within the studied experimental ranges, the optimum conditions for maximum Cr(VI) removal efficiency (72.1 %) after 60 min of photocatalytic treatment were: catalyst concentration 55 mg L-1, Cr(VI) concentration 20 mg L-1, pH 4, and 5 % (v/v) methanol concentration. Under optimum conditions, Cr(VI) reductive removal followed pseudo-first-order kinetics, and nearly complete removal took place within 90 min. The results revealed the feasibility and the effectiveness of PC/TiO2 as photocatalyst in reduction reactions due to their ability of e--h+ pair separation increasing the transfer of the photogenerated e- to the catalyst's surface and thus the reduction of Cr(VI).

  9. Time resolved pyrolysis of char

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ahrenfeldt, Jesper; Henriksen, Ulrik Birk

    pyrolysis, and slow heating in direct combination with mass spectrometry, gas chromatography/mass spectrometry and flame ionization detection, respectively. Characteristic ions derived from the flash pyrolysis-gas chromatography/mass spectrometry data enable the release of volatiles to be time and, hence...

  10. A scanning electron microscopy study of ash, char, deposits and fuels from straw combustion and co-combustion of coal and straw

    Energy Technology Data Exchange (ETDEWEB)

    Sund Soerensen, H.

    1998-07-01

    The SEM-study of samples from straw combustion and co-combustion of straw and coal have yielded a reference selection of representative images that will be useful for future comparison. The sample material encompassed potential fuels (wheat straw and grain), bottom ash, fly ash and deposits from straw combustion as well as fuels (coal and wheat straw), chars, bottom ash, fly ash and deposits from straw + coal co-combustion. Additionally, a variety of laboratory ashes were studied. SEM and CCSEM analysis of the samples have given a broad view of the inorganic components of straw and of the distribution of elements between individual ash particles and deposits. The CCSEM technique does, however, not detect dispersed inorganic elements in biomass, so to get a more complete visualization of the distribution of inorganic elements additional analyses must be performed, for example progressive leaching. In contrast, the CCSEM technique is efficient in characterizing the distribution of elements in ash particles and between ash fractions and deposits. The data for bottom ashes and fly ashes have indicated that binding of potassium to silicates occurs to a significant extent. The silicates can either be in the form of alumino-silicates or quartz (in co-combustion) or be present as straw-derived amorphous silica (in straw combustion). This process is important for two reasons. One is that potasium lowers the melting point of silica in the fly ash, potentially leading to troublesome deposits by particle impaction and sticking to heat transfer surfaces. The other is that the reaction between potassium and silica in the bottom ash binds part of the potassium meaning that it is not available for reaction with chlorine or sulphur to form KCl or K{sub 2}SO{sub 4}. Both phases are potentially troublesome because they can condense of surfaces to form a sticky layer onto which fly ash particles can adhere and by inducing corrosion beneath the deposit. It appears that in the studied

  11. Quantificação do teor de char e finos de coque no pó de balão do alto-forno por difração de raios-X

    OpenAIRE

    André da Silveira Machado

    2011-01-01

    A injeção de carvão pulverizado (PCI — pulverized coal injection) nos altos-fornos (AFs) é uma tecnologia utilizada pelas usinas siderúrgicas para aumentar a produtividade e diminuir o consumo de coque no AF. Nas últimas décadas as taxas de injeção de carvão pulverizado aumentaram na maior parte dos AFs. O principal problema associado à utilização de altas taxas de PCI é a geração de char (carvão incombusto) na zona de combustão. Este material percorre um caminho ascendente junto ao fluxo gas...

  12. Life Prediction of Large Lithium-Ion Battery Packs with Active and Passive Balancing

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ying [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zane, Regan [Utah State University; Anderson, Dyche [Ford Motor Company

    2017-07-03

    Lithium-ion battery packs take a major part of large-scale stationary energy storage systems. One challenge in reducing battery pack cost is to reduce pack size without compromising pack service performance and lifespan. Prognostic life model can be a powerful tool to handle the state of health (SOH) estimate and enable active life balancing strategy to reduce cell imbalance and extend pack life. This work proposed a life model using both empirical and physical-based approaches. The life model described the compounding effect of different degradations on the entire cell with an empirical model. Then its lower-level submodels considered the complex physical links between testing statistics (state of charge level, C-rate level, duty cycles, etc.) and the degradation reaction rates with respect to specific aging mechanisms. The hybrid approach made the life model generic, robust and stable regardless of battery chemistry and application usage. The model was validated with a custom pack with both passive and active balancing systems implemented, which created four different aging paths in the pack. The life model successfully captured the aging trajectories of all four paths. The life model prediction errors on capacity fade and resistance growth were within +/-3% and +/-5% of the experiment measurements.

  13. Large Neighborhood Search

    DEFF Research Database (Denmark)

    Pisinger, David; Røpke, Stefan

    2010-01-01

    Heuristics based on large neighborhood search have recently shown outstanding results in solving various transportation and scheduling problems. Large neighborhood search methods explore a complex neighborhood by use of heuristics. Using large neighborhoods makes it possible to find better candid...

  14. Transport et combustion de particules générées par un feu de végétation

    OpenAIRE

    Sardoy, Nicolas

    2007-01-01

    As a tool for understanding and mastery the phenomenon of spotfires (fire spread by lofted flaming or glowing plant debris, called firebrands), a physical model which simulates transport and combustion of firebrands during forest fire is developed. The combustion sub-model describes the most of the thermal degradation processes: pyrolysis of dry wood, combustion and gasification of char, thermal transfers... Aerodynamical sub-model takes into account drag and lift phenomena, as well as the ro...

  15. Large Pelagics Intercept Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Intercept Survey (LPIS) is a dockside survey of private and charterboat captains who have just completed fishing trips directed at large pelagic...

  16. Overvoltage protection of large power transformers

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Wiechowski, Wojciech Tomasz; Einarsdottir, Kristin

    2006-01-01

    This paper demonstrates the results from a detailed study of the overvoltage protection of a particular 400/150 kV 400 MVA power transformer. The work presented here is based on real-life power system substation design and data and initiated by Danish TSO Energinet.dk as a consequence of a serious...... transformer overvoltage damage. A simulation model for the entire system consisting of overhead line, transformer, surge arrester and earth grid has been created in PSCAD/EMTDC. Main focus has been put on the earth grid, which has been submodeled in details in MATLAB using an electromagnetic transient...... approach based on the thin-wire program made by J.H.Richmond in 1974 for NASA. The earth grid model is verified with excellent agreement compared to already published results. The overvoltage performance of the particular case is analyzed, and it is showed that the transformers LIWL have probably been...

  17. Adaptive Large Neighbourhood Search

    DEFF Research Database (Denmark)

    Røpke, Stefan

    Large neighborhood search is a metaheuristic that has gained popularity in recent years. The heuristic repeatedly moves from solution to solution by first partially destroying the solution and then repairing it. The best solution observed during this search is presented as the final solution....... This tutorial introduces the large neighborhood search metaheuristic and the variant adaptive large neighborhood search that dynamically tunes parameters of the heuristic while it is running. Both heuristics belong to a broader class of heuristics that are searching a solution space using very large...

  18. Large N Scalars

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2016-01-01

    We construct effective Lagrangians, and corresponding counting schemes, valid to describe the dynamics of the lowest lying large N stable massive composite state emerging in strongly coupled theories. The large N counting rules can now be employed when computing quantum corrections via an effective...... at the electroweak scale. To illustrate the formalism we consider the possibility that the Higgs emerges as: the lightest glueball of a new composite theory; the large N scalar meson in models of dynamical electroweak symmetry breaking; the large N pseudodilaton useful also for models of near-conformal dynamics...

  19. Development of a high-performance coal-fired power generating system with pyrolysis gas and char-fired high temperature furnace (HITAF). Quarterly progress report No. 3, July--September 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    A concept for an advanced coal-fired combined-cycle power generating system is currently being developed. The first phase of this three-phase program consists of conducting the necessary research and development to define the system, evaluate the economic and technical feasibility of the concept, and prepare an R & D plan to develop the concept further. Foster Wheeler Development Corporation is leading a team ofcompanies involved in this effort. The system proposed to meet these goals is a combined-cycle system where air for a gas turbine is indirectly heated to approximately 1800{degrees}F in furnaces fired with cool-derived fuels and then directly heated in a natural-gas-fired combustor up to about 2400{degrees}F. The system is based on a pyrolyzing process that converts the coal into a low-Btu fuel gas and char. The fuelgas is a relatively clean fuel, and it is fired to heat tube surfaces that are susceptible to corrosion and problems from ash deposition. In particular, the high-temperature air heater tubes, which will need tobe a ceramic material, will be located in a separate furnace or region of a furnace that is exposed to combustion products from the low-Btu fuel gas only. A simplified process flow diagram is shown.

  20. The West Coast steenbras Lithognathus aureti is a large ...

    African Journals Online (AJOL)

    denise

    brown to enhance definition of growth zones. Care was taken not to char the otoliths, because this tended to obscure growth patterns, ..... where t denotes days at liberty, L1 is fish length at first capture and L2 is fish length at recapture. The asymptotic length (L∞) was set at 73 cm for the southern population and at 84 cm for ...

  1. LARGE BUILDING RADON MANUAL

    Science.gov (United States)

    The report summarizes information on how bilding systems -- especially the heating, ventilating, and air-conditioning (HVAC) system -- inclurence radon entry into large buildings and can be used to mitigate radon problems. It addresses the fundamentals of large building HVAC syst...

  2. ERP inside Large Organizations

    Directory of Open Access Journals (Sweden)

    Constantin Daniel AVRAM

    2010-01-01

    Full Text Available Many large companies in Romania are still functioning without an ERP system. Instead they are using traditional application systems built around the strong boundaries of specific functions: finance, selling, HR, production. An ERP will offer lots of advantages among which the integration of functionalities and support for top management decisions. Although the total cost of ownership is not small and there are some risks when implementing an ERP inside large and very large organizations, having such a system is mandatory. Choosing the right product and vendor and using a correct risk management strategy, will ensure a successful implementation.

  3. Large Rotor Test Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — This test apparatus, when combined with the National Full-Scale Aerodynamics Complex, produces a thorough, full-scale test capability. The Large Rotor Test Apparatus...

  4. Large Pelagics Telephone Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Telephone Survey (LPTS) collects fishing effort information directly from captains holding Highly Migratory Species (HMS) permits (required by...

  5. Large Pelagics Biological Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Biological Survey (LPBS) collects additional length and weight information and body parts such as otoliths, caudal vertebrae, dorsal spines, and...

  6. Large Customers (DR Sellers)

    Energy Technology Data Exchange (ETDEWEB)

    Kiliccot, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-10-25

    State of the large customers for demand response integration of solar and wind into electric grid; openADR; CAISO; DR as a pseudo generation; commercial and industrial DR strategies; California regulations

  7. Large whale incident database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Large whale stranding, death, ship strike and entanglement incidents are all recorded to monitor the health of each population and track anthropogenic factors that...

  8. Developing Large Web Applications

    CERN Document Server

    Loudon, Kyle

    2010-01-01

    How do you create a mission-critical site that provides exceptional performance while remaining flexible, adaptable, and reliable 24/7? Written by the manager of a UI group at Yahoo!, Developing Large Web Applications offers practical steps for building rock-solid applications that remain effective even as you add features, functions, and users. You'll learn how to develop large web applications with the extreme precision required for other types of software. Avoid common coding and maintenance headaches as small websites add more pages, more code, and more programmersGet comprehensive soluti

  9. Death Writ Large

    Science.gov (United States)

    Kastenbaum, Robert

    2004-01-01

    Mainstream thanatology has devoted its efforts to improving the understanding, care, and social integration of people who are confronted with life-threatening illness or bereavement. This article suggests that it might now be time to expand the scope and mission to include large-scale death and death that occurs through complex and multi-domain…

  10. Large, Easily Deployable Structures

    Science.gov (United States)

    Agan, W. E.

    1983-01-01

    Study of concepts for large space structures will interest those designing scaffolding, radio towers, rescue equipment, and prefabricated shelters. Double-fold, double-cell module was selected for further design and for zero gravity testing. Concept is viable for deployment by humans outside space vehicle as well as by remotely operated manipulator.

  11. The large hadron computer

    CERN Multimedia

    Hirstius, Andreas

    2008-01-01

    Plans for dealing with the torrent of data from the Large Hadron Collider's detectors have made the CERN particle-phycis lab, yet again, a pioneer in computing as well as physics. The author describes the challenges of processing and storing data in the age of petabyt science. (4 pages)

  12. Dirac's Large Numbers Hypothesis

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 8. Dirac's Large Numbers Hypothesis. Biman Nath. Article-in-a-Box Volume 8 Issue 8 August 2003 pp 7-7. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/008/08/0007-0007. Author Affiliations.

  13. The Large Hadron Collider

    CERN Multimedia

    Wright, Alison

    2007-01-01

    "We are on the threshold of a new era in particle-physics research. In 2008, the Large Hadron Collider (LHC) - the hightest-energy accelerator ever built - will come into operation at CERN, the European labortory that straddles the French-Swiss border near Geneva." (1/2 page)

  14. Dimensioning large call centers

    NARCIS (Netherlands)

    S.C. Borst (Sem); A. Mandelbaum; M.I. Reiman

    2000-01-01

    textabstractWe develop a framework for asymptotic optimization of a queueing system. The motivation is the staffing problem of call centers with 100's of agents (or more). Such a call center is modeled as an M/M/N queue, where the number of agents~$N$ is large. Within our framework, we determine the

  15. Large superconducting magnets

    CERN Document Server

    Pérot, J

    1981-01-01

    Discusses the use of large superconducting magnets in the areas of particle physics, thermonuclear fusion, and magnetohydrodynamics. In addition to considering the physics of the superconducting state, the article considers machines such as BEBC (Big European Bubble Chamber) at CERN, the LINAC at SLAC and possible Tokamak applications. The future application of superconductors to high speed trains is discussed. (0 refs).

  16. Large Hadron Collider

    CERN Multimedia

    2007-01-01

    "In the spring 2008, the Large Hadron Collider (LHC) machine at CERN (the European Particle Physics laboratory) will be switched on for the first time. The huge machine is housed in a circular tunnel, 27 km long, excavated deep under the French-Swiss border near Geneva." (1,5 page)

  17. Novel large aperture EBCCD

    Science.gov (United States)

    Suzuki, Atsumu; Aoki, Shigeki; Haba, Junji; Sakuda, Makoto; Suyama, Motohiro

    2011-02-01

    A novel large aperture electron bombardment charge coupled device (EBCCD) has been developed. The diameter of its photocathode is 10 cm and it is the first EBCCD with such a large aperture. Its gain shows good linearity as a function of applied voltage up to -12 kV, where the gain is 2400. The spatial resolution was measured using ladder pattern charts. It is better than 2 line pairs/mm, which corresponds to 3.5 times the CCD pixel size. The spatial resolution was also measured with a copper foil pattern on a fluorescent screen irradiated with X-rays (14 and 18 keV) and a 60 keV gamma-ray from an americium source. The result was consistent with the measurement using ladder pattern charts. The output signal as a function of input light intensity shows better linearity than that of image intensifier tubes (IIT) as expected. We could detect cosmic rays passing through a scintillating fiber block and a plastic scintillator as a demonstration for a practical use in particle physics experiments. This kind of large aperture EBCCD can, for example, be used as an image sensor for a detector with a large number of readout channels and is expected to be additionally applied to other physics experiments.

  18. Risks of Large Portfolios.

    Science.gov (United States)

    Fan, Jianqing; Liao, Yuan; Shi, Xiaofeng

    2015-06-01

    The risk of a large portfolio is often estimated by substituting a good estimator of the volatility matrix. However, the accuracy of such a risk estimator is largely unknown. We study factor-based risk estimators under a large amount of assets, and introduce a high-confidence level upper bound (H-CLUB) to assess the estimation. The H-CLUB is constructed using the confidence interval of risk estimators with either known or unknown factors. We derive the limiting distribution of the estimated risks in high dimensionality. We find that when the dimension is large, the factor-based risk estimators have the same asymptotic variance no matter whether the factors are known or not, which is slightly smaller than that of the sample covariance-based estimator. Numerically, H-CLUB outperforms the traditional crude bounds, and provides an insightful risk assessment. In addition, our simulated results quantify the relative error in the risk estimation, which is usually negligible using 3-month daily data.

  19. Large myelomeningocele repair

    Directory of Open Access Journals (Sweden)

    Farideh Nejat

    2011-01-01

    Full Text Available Background: Wound closure is accomplished in most cases of myelomeningocele (MMC by undermining of the skin edges surrounding the defect. However, large defects cannot be closed reliably by this simple technique. Due to the technical challenge associated with large MMC, surgeons have devised different methods for repairing large defects. In this paper, we report our experience of managing large defects, which we believe bears a direct relationship to decrease the incidence of wound complications. Materials and Methods: Forty children with large MMCs underwent surgical repair and represent our experience. We recommend using all hairy skin around the defect as a way to decrease the tension on the edges of the wound and the possible subsequent necrosis. It is our experience that vertical incision on one or two flanks parallel to the midline can decrease the tension of the wound. Moreover, ventriculo-peritoneal shunting for children who developed hydrocephalus was performed simultaneously, which constitutes another recommendation for preventing fluid collection and build up of pressure on the wound. Results: Patients in this study were in the age range of 2 days to 8 years. The most common location of MMC was in the thoracolumbar area. All but four patients had severe weakness in lower extremities. We used as much hairy skin around the MMC sac as possible in all cases. Vertical incisions on one or both flanks and simultaneous shunt procedure were performed in 36 patients. We treated children with large MMC defects with acceptable tension-free closure. Nonetheless, three patients developed superficial skin infection and partial wound dehiscence, and they were managed conservatively. Conclusions: We recommend using all hairy skin around the MMC defect for closure of large defects. In cases that were expected to be at a higher risk to develop dehiscence release incisions on one or two flanks towards the fascia were found to be useful. Simultaneous

  20. Large reservoirs: Chapter 17

    Science.gov (United States)

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  1. The Large Hadron Collider

    CERN Document Server

    Evans, Lyndon

    2012-01-01

    The construction of the Large Hadron Collider (LHC) has been a massive endeavour spanning almost 30 years from conception to commissioning. Building the machine with the highest possible energy (7 TeV) in the existing large electron–positron (LEP) collider tunnel of 27 km circumference and with a tunnel diameter of only 3.8 m has required considerable innovation. The first was the development of a two-in-one magnet, where the two rings are integrated into a single magnetic structure. This compact two-in-one structure was essential for the LHC owing to the limited space available in the existing LEP collider tunnel and the cost. The second was a bold move to the use of superfluid helium cooling on a massive scale, which was imposed by the need to achieve a high (8.3 T) magnetic field using an affordable Nb-Ti superconductor.

  2. Large calcified subdural empyema.

    Science.gov (United States)

    Sarkar, S; Mazumder, U; Chowdhury, D; Dey, S K; Hossain, M; Nag, U K; Riaz, B K

    2012-04-01

    Subdural empyema is a known disease entity; however, calcified subdural empyema is uncommon. The authors present a case of an 11-year-old boy in whom there was diagnosed a chronic calcified subdural empyema 10 years after an attack of meningitis. The patient had suffered from generalized tonic clonic seizures occurring 2-6 times in a month. A large fronto-temporo-parietal craniotomy was carried out and the subdural empyema filled with numerous uncharacteristic tissue fragments with thick pus together with the partially calcified and ossified capsule was removed. The empyema mass was found to be sterile for bacteria. After the operation, no epileptic seizure occurred and the boy is on sodium valporate. We must emphasize the unusual occurrence of the chronic subdural empyema presenting with calcification-ossification and large size as observed in our case.

  3. Large Hadron Collider manual

    CERN Document Server

    Lavender, Gemma

    2018-01-01

    What is the universe made of? How did it start? This Manual tells the story of how physicists are seeking answers to these questions using the world’s largest particle smasher – the Large Hadron Collider – at the CERN laboratory on the Franco-Swiss border. Beginning with the first tentative steps taken to build the machine, the digestible text, supported by color photographs of the hardware involved, along with annotated schematic diagrams of the physics experiments, covers the particle accelerator’s greatest discoveries – from both the perspective of the writer and the scientists who work there. The Large Hadron Collider Manual is a full, comprehensive guide to the most famous, record-breaking physics experiment in the world, which continues to capture the public imagination as it provides new insight into the fundamental laws of nature.

  4. [Large vessel vasculitides].

    Science.gov (United States)

    Morović-Vergles, Jadranka; Puksić, Silva; Gracanin, Ana Gudelj

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in young ages. Although all large arteries can be affected, the aorta, subclavian and carotid arteries are most commonly involved. The most common symptoms included upper extremity claudication, hypertension, pain over the carotid arteries (carotidynia), dizziness and visual disturbances. Early diagnosis and treatment has improved the outcome in patients with TA.

  5. The Large Hadron Collider.

    Science.gov (United States)

    Evans, Lyndon

    2012-02-28

    The construction of the Large Hadron Collider (LHC) has been a massive endeavour spanning almost 30 years from conception to commissioning. Building the machine with the highest possible energy (7 TeV) in the existing large electron-positron (LEP) collider tunnel of 27 km circumference and with a tunnel diameter of only 3.8 m has required considerable innovation. The first was the development of a two-in-one magnet, where the two rings are integrated into a single magnetic structure. This compact two-in-one structure was essential for the LHC owing to the limited space available in the existing LEP collider tunnel and the cost. The second was a bold move to the use of superfluid helium cooling on a massive scale, which was imposed by the need to achieve a high (8.3 T) magnetic field using an affordable Nb-Ti superconductor.

  6. Large vessel vasculitides

    OpenAIRE

    Morović-Vergles, Jadranka; Pukšić, Silva; Gudelj Gračanin, Ana

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in y...

  7. Lymphomas of large cells.

    Science.gov (United States)

    Staples, W G; Gétaz, E P

    1977-09-03

    Historial aspects of the classification of large-cell lymphomas are described. Immunological characterization of the lymphomas has been made possible by identification of T and B lymphocytes according to their cell membrane surface characteristics. The pathogenesis of lymphomas has been clarified by the germinal (follicular) centre cell concepts of Lennert and Lukes and Collins. The various classifications are presented and compared. Whether these subdivisions will have any relevance in the clinical context remains to be seen.

  8. Large area LED package

    Science.gov (United States)

    Goullon, L.; Jordan, R.; Braun, T.; Bauer, J.; Becker, F.; Hutter, M.; Schneider-Ramelow, M.; Lang, K.-D.

    2015-03-01

    Solid state lighting using LED-dies is a rapidly growing market. LED-dies with the needed increasing luminous flux per chip area produce a lot of heat. Therefore an appropriate thermal management is required for general lighting with LEDdies. One way to avoid overheating and shorter lifetime is the use of many small LED-dies on a large area heat sink (down to 70 μm edge length), so that heat can spread into a large area while at the same time light also appears on a larger area. The handling with such small LED-dies is very difficult because they are too small to be picked with common equipment. Therefore a new concept called collective transfer bonding using a temporary carrier chip was developed. A further benefit of this new technology is the high precision assembly as well as the plane parallel assembly of the LED-dies which is necessary for wire bonding. It has been shown that hundred functional LED-dies were transferred and soldered at the same time. After the assembly a cost effective established PCB-technology was applied to produce a large-area light source consisting of many small LED-dies and electrically connected on a PCB-substrate. The top contacts of the LED-dies were realized by laminating an adhesive copper sheet followed by LDI structuring as known from PCB-via-technology. This assembly can be completed by adding converting and light forming optical elements. In summary two technologies based on standard SMD and PCB technology have been developed for panel level LED packaging up to 610x 457 mm2 area size.

  9. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    possible to achieve a drop in relative piglet mortality and the related welfare problems. However, there will be a growing problem with the need to use foster or nurse sows which may have negative effects on both sows and piglets. This gives rise to new challenges for management....... adverse consequences for animal welfare of Danish breeding for large litter sizes due to increased piglet mortality and the subsequent attempts to reverse these consequences by breeding for number of live piglets at day five rather than number of piglets born. By this change of breeding goal it seems...

  10. Large stable magnetic domains

    Science.gov (United States)

    Pulliam, G. R.; Ross, W. E.; MacNeal, B.; Bailey, R. F.

    1982-03-01

    Large, thin-film single domain areas have been observed, in the absence of a bias field, in garnets with magnetization perpendicular to the film plane.1,2 The domain stability in the work by Krumme1 was attributed to a combination of low saturation magnetization and a low Curie temperature. Uchishiba2 relates the stability in his double layer system to appropriate anisotropy fields in one layer compared to the magnetization in the other layer. A more complete model for large domain stability in a bias field free environment is given in this work. Three distinct stability regimes are predicted by the model and all have been observed experimentally. Areas 3.5-cm in diameter have been made into stable single domains. This was achieved in a material showing a zero bias strip width of 4.5 μm. The single domain diameter was, therefore, 7500 times the equilibrium energy domain width. The technique developed and the model have led to a new means for observing magnetic defects. More importantly, it also offers a means for measuring the strength of the defects. Possible applications of the model are also discussed.

  11. Large Helical Device project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    In this book, the results of the scientific research on the design, trial manufacture and manufacturing processes of the Large Helical Device which was constructed in National Institute for Fusion Science are summarized. The LHD is the largest helical device in the world, and the largest superconducting system in the world. It possesses the following features: the optimization of heliotron magnetic field coordination, the adoption of superconducting magnets for 2 helical magnetic field coils and 6 poloidal coils, the adoption of helical diverter which enables steady plasma experiment, the flexible specification as the experimental facility and so on. The construction has been carried out smoothly, and in March, 1998, first plasma was generated. The outline of the Large Helical Device project, the physical design, the equipment design, the research and development of superconductivity and low temperature system, the design and manufacture of the superconducting and low temperature systems, the design and manufacture of the power source and superconducting bus-line, vacuum vessel and others, electron cyclotron heating, neutral beam injection and ion cyclotron RF heating, measurement system, control and data processing, safety management, the theory and analysis of LHD plasma, the visualization of the result of theoretical analysis, the analysis of the experimental data, and the experiment plan are described. (K.I.)

  12. Estimation of Transport Trajectory and Residence Time in Large River–Lake Systems: Application to Poyang Lake (China Using a Combined Model Approach

    Directory of Open Access Journals (Sweden)

    Yunliang Li

    2015-09-01

    Full Text Available The biochemical processes and associated water quality in many lakes mainly depend on their transport behaviors. Most existing methodologies for investigating transport behaviors are based on physically based numerical models. The pollutant transport trajectory and residence time of Poyang Lake are thought to have important implications for the steadily deteriorating water quality and the associated rapid environmental changes during the flood period. This study used a hydrodynamic model (MIKE 21 in conjunction with transport and particle-tracking sub-models to provide comprehensive investigation of transport behaviors in Poyang Lake. Model simulations reveal that the lake’s prevailing water flow patterns cause a unique transport trajectory that primarily develops from the catchment river mouths to the downstream area along the lake’s main flow channels, similar to a river-transport behavior. Particle tracking results show that the mean residence time of the lake is 89 days during July–September. The effect of the Yangtze River (the effluent of the lake on the residence time is stronger than that of the catchment river inflows. The current study represents a first attempt to use a combined model approach to provide insights into the transport behaviors for a large river–lake system, given proposals to manage the pollutant inputs both directly to the lake and catchment rivers.

  13. Numerical modeling of mixing in large stably stratified enclosures using TRACMIX++

    Science.gov (United States)

    Christensen, Jakob

    This PhD dissertation focuses on the numerical modeling of stably stratified large enclosures. In stably stratified volumes, the distribution of temperature, species concentration etc become essentially 1-D throughout most of the enclosure. When the fluid in an enclosure is stratified, wall boundary buoyant jets, forced buoyant jets (injection of fluid) and natural convection plumes become the primary sources of mixing. The time constants for the buoyant jets may be considered as much smaller than the time constant for the mixing of the stratified ambient fluid, provided the combined volume occupied by the buoyant jets is small compared to the volume of the enclosure. Therefore, fluid transport by the buoyant jets may be considered as occurring instantaneously. For this reason this work focuses on deriving a numerical method which is able to solve the 1-D vertical fluid conservation equations, as given in Peterson (1994). Starting with the Eulerian fluid conservation equations given in Peterson (1994), a set of Lagrangian fluid conservation equations were derived. Combining the Lagrangian approach with operator splitting such that the convective step and the diffusive step is separated renders a very efficient, accurate, and stable numerical method as it is shown in this text. Since the stratified flow field frequently exhibits very strong gradients or so-called fronts, the generation of these fronts has to be accurately detected and tracked by the numerical method. Flow in stably stratified large enclosure has typically been modeled in the past using 1- or 2-zone models. The present model is new in that it belongs to the K-zone models where the number of zones is arbitrarily large and depends on the complexity of the solution and the accuracy requirement set by the user. Because fronts are present in the flow field, a Lagrangian type numerical method is used. A Lagrangian method facilitates front tracking and prevents numerical diffusion from altering the shape of

  14. Large Scale Solar Heating

    DEFF Research Database (Denmark)

    Heller, Alfred

    2001-01-01

    The main objective of the research was to evaluate large-scale solar heating connected to district heating (CSDHP), to build up a simulation tool and to demonstrate the application of the simulation tool for design studies and on a local energy planning case. The evaluation was mainly carried out......). Simulation programs are proposed as control supporting tool for daily operation and performance prediction of central solar heating plants. Finaly the CSHP technolgy is put into persepctive with respect to alternatives and a short discussion on the barries and breakthrough of the technology are given....... model is designed and validated on the Marstal case. Applying the Danish Reference Year, a design tool is presented. The simulation tool is used for proposals for application of alternative designs, including high-performance solar collector types (trough solar collectors, vaccum pipe collectors...

  15. The Large Hadron Collider

    Science.gov (United States)

    Evans, Lyndon

    2011-11-01

    The Large Hadron Collider (LHC) is the most complex instrument ever built for particle physics research. It will, for the first time, provide access to the TeV-energy scale. Numerous technological innovations are necessary to achieve this goal. For example, two counterrotating proton beams are guided and focused by superconducting magnets whose novel two-in-one structure saves cost and allowed the machine to be installed in an existing tunnel. The very high (>8-T) field in the dipoles can be achieved only by cooling them below the transition temperature of liquid helium to the superfluid state. More than 80 tons of superfluid helium are needed to cool the whole machine. So far, the LHC has behaved reliably and predictably. Single-bunch currents 30% above the design value have been achieved, and the luminosity has increased by five orders of magnitude. In this review, I briefly describe the design principles of the major systems and discuss some initial results.

  16. Archaeobotanical Investigation of Charred and Desiccated Fruit ...

    African Journals Online (AJOL)

    The excavations were conducted by the Italian Archaeological Expedition in East Sudan (IAEES) at the site of Mahal Teglinos, Kassala, northeast Sudan in the years 1991, 2013 and 2014. Identification and comparative study was conducted in the laboratories of Addis Ababa University and the Bio-archaeological Research ...

  17. Mechanisms of Char Formation during Flammability.

    Science.gov (United States)

    1980-02-25

    CCO. and the resulting polybenzoxazole from 4-NO2 PMT has higher heat resistance than that from 4-NO 2PMI. Although poly(3-nitro-1,4-phenylene tere...Combust., 9th, Cornell Univ., Ithaca, NY, pp. 733-46 (1962). 5. J. Preston, High Performance Fibers from Aromatic Polymers,. Polymer Eng. and Sd., 16(5

  18. Medicaid CHIP Environmental Scanning and Program Char...

    Data.gov (United States)

    U.S. Department of Health & Human Services — ESPC development is sponsored by the CMS Center for Medicare and Medicaid Innovation in partnership with the Center for Medicaid and CHIP Services (CMCS) under the...

  19. physicochemical char selected farms in rijiyar ysicochemical ...

    African Journals Online (AJOL)

    userpc

    In the outer layer of the earth's cru about 98% of the total crust is composed o mainly eight elements by weight: Oxygen(47%. Silicon. (28%),. Aluminum. (8%), ..... taken up by plants. For this reason it serves as an indicator for soil contamination of plant samples. Its estimation is sometimes required in studies on soil formation ...

  20. OPTIMIZATION OF CHAR FOR NOx REMOVAL

    Energy Technology Data Exchange (ETDEWEB)

    J. Phillips; L.R. Radovic; B. Xia; J.A. Menendez

    1999-09-01

    Work performed for this study demonstrates that the temperature of treatment and the identity of the treatment gas both strongly impact the surface chemistry of activated carbon. Two commercial activated carbons were treated in either N{sub 2} or H{sub 2} at different temperatures up to 2600 C. Several techniques--including microcalorimetry, point of zero charge measurements, thermal desorption--were used to provide insight into important aspects of the chemical surface properties. The results show that activated carbons treated at high temperatures (ca. 950 C) in hydrogen will not react with oxygen and water at ambient temperatures; moreover, surfaces created in this fashion have stable properties in ambient conditions for many months. In contrast, the same carbons treated in an inert gas (e.g., N{sub 2}) will react strongly with oxygen and water at ambient temperatures. In the presence of platinum (or any other noble metal), stable basic carbons, which will not adsorb oxygen in ambient laboratory conditions, can be created via a relatively low-temperature process. Treatment at higher temperatures (>1500 C) produced increasingly stable surfaces in either N{sub 2} or H{sub 2}. A structural model is proposed. To wit: Treatment at high temperatures in any gas will lead to the desorption of oxygen surface functionalities in the form of CO and/or CO{sub 2}. Absent any atom rearrangement, the desorption of these species will leave highly unsaturated carbon atoms (''dangling carbons'') on the surface, which can easily adsorb O{sub 2} and H{sub 2}O. In an inert gas these ''dangling carbons'' will remain, but hydrogen treatments will remove these species and leave the surface with less energetic sites, which can only adsorb O{sub 2} at elevated temperatures. Specifically, hydrogen reacts with any highly unsaturated carbons in the surface to form methane. At temperatures greater than 1500 C (e.g., 1800 C, 2600 C), structural annealing takes place and the consequent growth in the size of graphene layers eliminates the highly energetic dangling carbon sites. The basicity of the surface originates from two types of Lewis base sites: the localized electron pairs at the edges of the graphene layers and the delocalized {pi} electrons on the basal planes. A hydrogen spillover mechanism was proposed here to explain the low-temperature process for the stable basic carbon. The role played by platinum (or any noble metal) is to produce atomic hydrogen, which spills over onto the carbon surface. This atomic hydrogen hydrogasifies the most reactive, unsaturated carbon atoms at far lower temperatures than molecular hydrogen, thus leading to surface stabilization at relatively low temperatures.

  1. KINETICS AND MECHANISMS OF NOx - CHAR REDUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Suuberg, E.M.

    1998-06-19

    This study was undertaken in order to improve understanding of several aspects of the NO-carbon reaction. This reaction is of practical importance in combustion systems, but its close examination also provides some fundamental insight into oxidizing gas-carbon reactions. As part of this study, a comprehensive literature review of earlier work on this reaction has been published (Aarna and Suuberg, Fuel, 1997, 76, 475-491). It has been thought for some time that the kinetics of the NO-carbon reaction are unusual, in that they often show a two-regime Arrhenius behavior. It has, however, turned out during this work that NO is not alone in this regard. In this laboratory, we also uncovered evidence of two kinetic regime behavior in CO{sub 2} gasification. In another laboratory, a former colleague has identified the same behavior in N{sub 2}O. The low temperature reaction regime always shows an activation energy which is lower than that in the high temperature regime, leaving little doubt that a shift in mechanism, as opposed to transport limitations, dictates the behavior. The activation energy of the low temperature regime of these reactions is typically less than 100 kJ/mol, and the activation energy of the high temperature regime is generally considerably in excess of this value. In this study, we have resolved some apparent inconsistencies in the explanation of the low temperature regime, whose rate has generally been ascribed to desorption-controlled processes. Part of the problem in characterization of the different temperature regimes is that they overlap to a high degree. It is difficult to probe the low temperature regime experimentally, because of slow relaxation of the surface oxides in that regime. Using careful experimental techniques, we were able to demonstrate that the low temperature regime is indeed characterized by zero order in NO, as it must be. A separate study is being carried out to model the behavior in this regime in NO and in other gases, and the results will be presented shortly.

  2. Anaplastic large cell neuroblastoma.

    Science.gov (United States)

    Abramowsky, Carlos R; Katzenstein, Howard M; Alvarado, Carlos S; Shehata, Bahig M

    2009-01-01

    Anaplastic large cell neuroblastomas (ALCNB) are a subset of undifferentiated neuroblastomas with marked pleomorphic and anaplastic features that render them diagnostically challenging. We reviewed the records of all patients diagnosed with ALCNB at Children's Healthcare of Atlanta (Egleston Children's Hospital) for their clinical, biologic, and pathologic characteristics and their treatment outcomes. From 1998 to 2006, 7 patients were diagnosed with ALCNB. All patients presented with abdominal-pelvic masses, 3 of them of adrenal origin and 2 with thoracic extension, with clinical stages 3 or 4, and were considered to have high-risk disease. The N-MYC oncogene was amplified in 3 cases and catecholamines were elevated in 5 of 6 patients tested. All pretreatment tumors demonstrate pleomorphic, anaplastic morphology with bizarre mitoses admixed with undifferentiated but monomorphic cells with minimal if any neuropil or neuro-ganglionic differentiation. Immunohistochemical markers for neuron specific enolase (NSE) and synaptophysin were strongly positive in all specimens and chromogranin in 4 of 5. Interestingly, all tumors showed strong Fli-1 nuclear positivity despite a negative CD-99 stain. However, reverse transcription polymerase chain reaction or fluorescent in-situ hybridization testing for Ewing sarcoma transcripts was negative in 4 available specimens. This same Fli-1 antibody had tested negative on 30 conventional neuroblastomas, indicating a peculiar cross reactivity with this subset of ALCNB. Posttreatment biopsies showed maturation changes to more conventional neuroblastoma histology in 5 of the 7 cases. Follow-up ranged from 9 months to 4 years from diagnosis (median: 25 months). Five patients are still alive after treatment, 1 died 9 months after diagnosis, and another patient refused high-risk therapy and progressed and died 9 months from diagnosis. Anaplastic large cell neuroblastomas are a subset of undifferentiated neuroblastomas characterized by the

  3. Large-scale structure

    CERN Document Server

    White, S D M

    1993-01-01

    Abstract. Recent observational surveys have made substantial progress in quantifying the structure of the Universe on large scales. Galaxy density and galaxy velocity fields show deviations from the predictions of a homogeneous and isotropic world model on scales approaching one percent of the current hori— zon scale. A comparison of the amplitudes in density and in velocity provides the first direct dynamical evidence in favour of a high mean density similar to that required for closure. The fluctuations observed on these scales have the amplitude predicted by the standard Cold Dark Matter (CDM) model when this model is normalised to agree with the microwave background fluc- tuations measured on much larger scales by the COBE satellite. However, a CDM model with this amplitude appears inconsistent with observational data on smaller scales. In addition it predicts a scale dependence of fluctua— tion amplitude which disagrees with that observed for galaxies in the APM survey of two million faint galaxi...

  4. Large Crater Clustering tool

    Science.gov (United States)

    Laura, Jason; Skinner, James A.; Hunter, Marc A.

    2017-08-01

    In this paper we present the Large Crater Clustering (LCC) tool set, an ArcGIS plugin that supports the quantitative approximation of a primary impact location from user-identified locations of possible secondary impact craters or the long-axes of clustered secondary craters. The identification of primary impact craters directly supports planetary geologic mapping and topical science studies where the chronostratigraphic age of some geologic units may be known, but more distant features have questionable geologic ages. Previous works (e.g., McEwen et al., 2005; Dundas and McEwen, 2007) have shown that the source of secondary impact craters can be estimated from secondary impact craters. This work adapts those methods into a statistically robust tool set. We describe the four individual tools within the LCC tool set to support: (1) processing individually digitized point observations (craters), (2) estimating the directional distribution of a clustered set of craters, back projecting the potential flight paths (crater clusters or linearly approximated catenae or lineaments), (3) intersecting projected paths, and (4) intersecting back-projected trajectories to approximate the local of potential source primary craters. We present two case studies using secondary impact features mapped in two regions of Mars. We demonstrate that the tool is able to quantitatively identify primary impacts and supports the improved qualitative interpretation of potential secondary crater flight trajectories.

  5. Large Databases in Astronomy

    Science.gov (United States)

    Szalay, Alexander S.; Gray, Jim; Kunszt, Peter; Thakar, Anirudha; Slutz, Don

    The next-generation astronomy digital archives will cover most of the sky at fine resolution in many wavelengths, from X-rays through ultraviolet, optical, and infrared. The archives will be stored at diverse geographical locations. The intensive use of advanced data archives will enable astronomers to explore their data interactively. Data access will be aided by multidimensional spatial and attribute indices. The data will be partitioned in many ways. Small tag indices consisting of the most popular attributes will accelerate frequent searches. Splitting the data among multiple servers will allow parallel, scalable I/O and parallel data analysis. Hashing techniques will allow efficient clustering, and pair-wise comparison algorithms that should parallelize nicely. Randomly sampled subsets will allow debugging otherwise large queries at the desktop. Central servers will operate a data pump to support sweep searches touching most of the data. The anticipated queries will require special operators related to angular distances and complex similarity tests of object properties, like shapes, colors, velocity vectors, or temporal behaviors. These issues pose interesting data management challenges.

  6. Large scale tracking algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Love, Joshua Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Melgaard, David Kennett [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pitts, Todd Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zollweg, Joshua David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Dylan Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nandy, Prabal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Whitlow, Gary L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Byrne, Raymond Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  7. Large Format Radiographic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    J. S. Rohrer; Lacey Stewart; M. D. Wilke; N. S. King; S. A Baker; Wilfred Lewis

    1999-08-01

    Radiographic imaging continues to be a key diagnostic in many areas at Los Alamos National Laboratory (LANL). Radiographic recording systems have taken on many form, from high repetition-rate, gated systems to film recording and storage phosphors. Some systems are designed for synchronization to an accelerator while others may be single shot or may record a frame sequence in a dynamic radiography experiment. While film recording remains a reliable standby in the radiographic community, there is growing interest in investigating electronic recording for many applications. The advantages of real time access to remote data acquisition are highly attractive. Cooled CCD camera systems are capable of providing greater sensitivity with improved signal-to-noise ratio. This paper begins with a review of performance characteristics of the Bechtel Nevada large format imaging system, a gated system capable of viewing scintillators up to 300 mm in diameter. We then examine configuration alternatives in lens coupled and fiber optically coupled electro-optical recording systems. Areas of investigation include tradeoffs between fiber optic and lens coupling, methods of image magnification, and spectral matching from scintillator to CCD camera. Key performance features discussed include field of view, resolution, sensitivity, dynamic range, and system noise characteristics.

  8. Three-dimensional submodel for modelling of joints in precast concrete structures

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao

    2016-01-01

    The shear capacity of in-situ cast joints is crucial to the overall stability of precast concrete structures. The current design is based on empirical formulas, which account for neither the reinforcement layout of the joint nor the three-dimensional stress states present within the joint...

  9. Lower bound element and submodel for modelling of joints between precast concrete panels

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao

    2015-01-01

    In practice, precast concrete structures are designed using either analytical methods or linear finite element tools, and the in-situ cast joints between the precast panels are assessed using conservative empirical design formulas. This often leads to a suboptimal design, and local mechanisms...

  10. River water quality model no. 1 (RWQM1): III. Biochemical submodel selection

    DEFF Research Database (Denmark)

    Vanrolleghem, P.; Borchardt, D.; Henze, Mogens

    2001-01-01

    The new River Water Quality Model no.1 introduced in the two accompanying papers by Shanahan et al. and Reichert et al. is comprehensive. Shanahan et al. introduced a six-step decision procedure to select the necessary model features for a certain application. This paper specifically addresses on...

  11. Laboratory for Large Data Research

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: The Laboratory for Large Data Research (LDR) addresses a critical need to rapidly prototype shared, unified access to large amounts of data across both the...

  12. Large-D gravity and low-D strings.

    Science.gov (United States)

    Emparan, Roberto; Grumiller, Daniel; Tanabe, Kentaro

    2013-06-21

    We show that in the limit of a large number of dimensions a wide class of nonextremal neutral black holes has a universal near-horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a two-dimensional target space. Its conformal symmetry explains the properties of massless scalars found recently in the large-D limit. For black branes with string charges, the near-horizon geometry is that of the three-dimensional black strings of Horne and Horowitz. The analogies between the α' expansion in string theory and the large-D expansion in gravity suggest a possible effective string description of the large-D limit of black holes. We comment on applications to several subjects, in particular to the problem of critical collapse.

  13. Large Deviations for Random Trees.

    Science.gov (United States)

    Bakhtin, Yuri; Heitsch, Christine

    2008-08-01

    We consider large random trees under Gibbs distributions and prove a Large Deviation Principle (LDP) for the distribution of degrees of vertices of the tree. The LDP rate function is given explicitly. An immediate consequence is a Law of Large Numbers for the distribution of vertex degrees in a large random tree. Our motivation for this study comes from the analysis of RNA secondary structures.

  14. Large deviations and idempotent probability

    CERN Document Server

    Puhalskii, Anatolii

    2001-01-01

    In the view of many probabilists, author Anatolii Puhalskii''s research results stand among the most significant achievements in the modern theory of large deviations. In fact, his work marked a turning point in the depth of our understanding of the connections between the large deviation principle (LDP) and well-known methods for establishing weak convergence results.Large Deviations and Idempotent Probability expounds upon the recent methodology of building large deviation theory along the lines of weak convergence theory. The author develops an idempotent (or maxitive) probability theory, introduces idempotent analogues of martingales (maxingales), Wiener and Poisson processes, and Ito differential equations, and studies their properties. The large deviation principle for stochastic processes is formulated as a certain type of convergence of stochastic processes to idempotent processes. The author calls this large deviation convergence.The approach to establishing large deviation convergence uses novel com...

  15. Measurement and modeling of advanced coal conversion processes, Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G. [and others

    1993-06-01

    A two dimensional, steady-state model for describing a variety of reactive and nonreactive flows, including pulverized coal combustion and gasification, is presented. The model, referred to as 93-PCGC-2 is applicable to cylindrical, axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using a discrete ordinates method. The particle phase is modeled in a lagrangian framework, such that mean paths of particle groups are followed. A new coal-general devolatilization submodel (FG-DVC) with coal swelling and char reactivity submodels has been added.

  16. Characterisation of particulate matter and gaseous emissions from a large ship diesel engine

    Science.gov (United States)

    Moldanová, Jana; Fridell, Erik; Popovicheva, Olga; Demirdjian, Benjamin; Tishkova, Victoria; Faccinetto, Alessandro; Focsa, Cristian

    Composition of exhaust from a ship diesel engine using heavy fuel oil (HFO) was investigated onboard a large cargo vessel. The emitted particulate matter (PM) properties related to environmental and health impacts were investigated along with composition of the gas-phase emissions. Mass, size distribution, chemical composition and microphysical structure of the PM were investigated. The emission factor for PM was 5.3 g (kg fuel) -1. The mass size distribution showed a bimodal shape with two maxima: one in the accumulation mode with mean particle diameter DP around 0.5 μm and one in the coarse mode at DP around 7 μm. The PM composition was dominated by organic carbon (OC), ash and sulphate while the elemental carbon (EC) composed only a few percent of the total PM. Increase of the PM in exhaust upon cooling was associated with increase of OC and sulphate. Laser analysis of the adsorbed phase in the cooled exhaust showed presence of a rich mixture of polycyclic aromatic hydrocarbon (PAH) species with molecular mass 178-300 amu while PM collected in the hot exhaust showed only four PAH masses. Microstructure and elemental analysis of ship combustion residuals indicate three distinct morphological structures with different chemical composition: soot aggregates, significantly metal polluted; char particles, clean or containing minerals; mineral and/or ash particles. Additionally, organic carbon particles of unburned fuel or/and lubricating oil origin were observed. Hazardous constituents from the combustion of heavy fuel oil such as transitional and alkali earth metals (V, Ni, Ca, Fe) were observed in the PM samples. Measurements of gaseous composition in the exhaust of this particular ship showed emission factors that are on the low side of the interval of global emission factors published in literature for NO x, hydrocarbons (HC) and CO.

  17. Large-scale data analytics

    CERN Document Server

    Gkoulalas-Divanis, Aris

    2014-01-01

    Provides cutting-edge research in large-scale data analytics from diverse scientific areas Surveys varied subject areas and reports on individual results of research in the field Shares many tips and insights into large-scale data analytics from authors and editors with long-term experience and specialization in the field

  18. State estimation for large ensembles

    NARCIS (Netherlands)

    Gill, R.D.; Massar, S.

    2000-01-01

    We consider the problem of estimating the state of a large but nite number N of identical quantum systems. As N becomes large the problem simplies dramatically. The only relevant measure of the quality of estimation becomes the mean quadratic error matrix. Here we present a bound on this quantity: a

  19. State estimation for large ensembles

    NARCIS (Netherlands)

    Gill, R.D.; Massar, S.

    1999-01-01

    We consider the problem of estimating the state of a large but nite number N of identical quantum systems In the limit of large N the problem simplies In particular the only relevant measure of the quality of the estimation is the mean quadratic error matrix Here we present a bound on the mean

  20. Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char Effet des cendres sur l’activité des porteurs d’oxygène dans la combustion du charbon en boucle chimique

    Directory of Open Access Journals (Sweden)

    Rubel A.

    2011-02-01

    Full Text Available The application of Chemical Looping Combustion (CLC to solid fuels is being investigated at the University of Kentucky, Center for Applied Energy Research (CAER with the aim of the development of a Pressurized Chemical Looping Combustion/Gasification (PCLC/G process for the generation of electricity from coal. One important aspect of the CLC of solid fuel is the understanding of the effect of ash on the reactivity of Oxygen Carriers (OCs. The effect of ash on the redox capabilities of two different iron oxide OCs and on their ability to oxidize coal char was studied. To determine the effect of ash on the reactivity and recycle of the OCs through multiple redox cycles, fly ash from a coal-fired power plant was used. These experiments were performed in a TGMS system using 500 mg of ash/OC mixtures containing different ash concentrations up to 75%. The reducing gas was composed of 10% H2, 15% CO, 20% CO2, and a balance of Ar and the oxidizing gas was 20% O2 in Ar. Oxidation/reductions were carried to near completion. The ash was found to contain OC activity related to inherent iron present in the ash confirmed by XRD. This resulted in increased weight gain/loss on oxidation/reduction. The rate of oxidation/reduction increased with ash concentration due to increased porosity of the OC/ash mixture and better access of the reactive gases to the OC target sites. The two OCs were then used to combust a beneficiated coal char in the TGMS with the only oxygen supplied by an iron oxide OC. The starting mixture was 10% char and 90% of one of two OCs studied. The spent material containing reduced OC and ash was re-oxidized and 10% more char was added for a second reduction of the OC and oxidation of the added char. This procedure was repeated for 5 cycles increasing the ash concentrations from 5 to 25% in the char/ash/OC mixture. Carbon removal was 92 to 97.8 and 97.3 to 99.7% for the two different iron oxide OCs tested. Ash was not detrimental to the

  1. Measuring happiness in large population

    Science.gov (United States)

    Wenas, Annabelle; Sjahputri, Smita; Takwin, Bagus; Primaldhi, Alfindra; Muhamad, Roby

    2016-01-01

    The ability to know emotional states for large number of people is important, for example, to ensure the effectiveness of public policies. In this study, we propose a measure of happiness that can be used in large scale population that is based on the analysis of Indonesian language lexicons. Here, we incorporate human assessment of Indonesian words, then quantify happiness on large-scale of texts gathered from twitter conversations. We used two psychological constructs to measure happiness: valence and arousal. We found that Indonesian words have tendency towards positive emotions. We also identified several happiness patterns during days of the week, hours of the day, and selected conversation topics.

  2. Large networks and graph limits

    CERN Document Server

    Lovász, László

    2012-01-01

    Recently, it became apparent that a large number of the most interesting structures and phenomena of the world can be described by networks. Developing a mathematical theory of very large networks is an important challenge. This book describes one recent approach to this theory, the limit theory of graphs, which has emerged over the last decade. The theory has rich connections with other approaches to the study of large networks, such as "property testing" in computer science and regularity partition in graph theory. It has several applications in extremal graph theory, including the exact for

  3. Large Hadron Collider nears completion

    CERN Multimedia

    2008-01-01

    Installation of the final component of the Large Hadron Collider particle accelerator is under way along the Franco-Swiss border near Geneva, Switzerland. When completed this summer, the LHC will be the world's largest and most complex scientific instrument.

  4. Disorders of the Large Intestine

    Science.gov (United States)

    ... of Medicine, Division of Digestive Diseases; Professor of Psychology, University of North Carolina, Chapel Hill, NC, IFFGD ... Intestine Large Intestine Anorectal and Pelvic Floor Area Personal Stories Resources We provide a wide range of ...

  5. Large traders in financial markets

    OpenAIRE

    Fagan, Stephen Perry

    2011-01-01

    Large traders in financial markets care a lot about the supply of liquidity - factors that allow them to trade quickly without incurring a significant cost - since the size of their trading can cause a large market impact if they demand more liquidity than is currently available. The first study examines an important and recurring cause of liquidity shocks in futures markets - the accumulation of extreme and opposing positions by hedgers and speculators. These two classes of traders are found...

  6. Optimization theory for large systems

    CERN Document Server

    Lasdon, Leon S

    2002-01-01

    Important text examines most significant algorithms for optimizing large systems and clarifying relations between optimization procedures. Much data appear as charts and graphs and will be highly valuable to readers in selecting a method and estimating computer time and cost in problem-solving. Initial chapter on linear and nonlinear programming presents all necessary background for subjects covered in rest of book. Second chapter illustrates how large-scale mathematical programs arise from real-world problems. Appendixes. List of Symbols.

  7. Observations at large zenith angles

    CERN Document Server

    Schroeder, F

    2000-01-01

    Cherenkov telescope observations at zenith angles >70 deg. are capable of providing large collection areas for high energy gamma-induced air showers. In order to provide a full Monte Carlo simulation of the large zenith angle observations the air shower simulation code CORSIKA was modified to treat particles in a curved geometry. First results of studies with the stand alone telescope HEGRA CT1 are presented.

  8. Large-scale solar heat

    Energy Technology Data Exchange (ETDEWEB)

    Tolonen, J.; Konttinen, P.; Lund, P. [Helsinki Univ. of Technology, Otaniemi (Finland). Dept. of Engineering Physics and Mathematics

    1998-12-31

    In this project a large domestic solar heating system was built and a solar district heating system was modelled and simulated. Objectives were to improve the performance and reduce costs of a large-scale solar heating system. As a result of the project the benefit/cost ratio can be increased by 40 % through dimensioning and optimising the system at the designing stage. (orig.)

  9. Can we save large carnivores without losing large carnivore science?

    Science.gov (United States)

    Allen, Benjamin L.; Allen, Lee R.; Andrén, Henrik; Ballard, Guy; Boitani, Luigi; Engeman, Richard M.; Fleming, Peter J.S.; Haswell, Peter M.; Ford, Adam T.; Kowalczyk, Rafał; Mech, L. David; Linnell, John D.C.; Parker, Daniel M.

    2017-01-01

    Large carnivores are depicted to shape entire ecosystems through top-down processes. Studies describing these processes are often used to support interventionist wildlife management practices, including carnivore reintroduction or lethal control programs. Unfortunately, there is an increasing tendency to ignore, disregard or devalue fundamental principles of the scientific method when communicating the reliability of current evidence for the ecological roles that large carnivores may play, eroding public confidence in large carnivore science and scientists. Here, we discuss six interrelated issues that currently undermine the reliability of the available literature on the ecological roles of large carnivores: (1) the overall paucity of available data, (2) reliability of carnivore population sampling techniques, (3) general disregard for alternative hypotheses to top-down forcing, (4) lack of applied science studies, (5) frequent use of logical fallacies, and (6) generalisation of results from relatively pristine systems to those substantially altered by humans. We first describe how widespread these issues are, and given this, show, for example, that evidence for the roles of wolves (Canis lupus) and dingoes (Canis lupus dingo) in initiating trophic cascades is not as strong as is often claimed. Managers and policy makers should exercise caution when relying on this literature to inform wildlife management decisions. We emphasise the value of manipulative experiments and discuss the role of scientific knowledge in the decision-making process. We hope that the issues we raise here prompt deeper consideration of actual evidence, leading towards an improvement in both the rigour and communication of large carnivore science.

  10. Quantum spin liquids: a large-S route

    Energy Technology Data Exchange (ETDEWEB)

    Tchernyshyov, Oleg [Department of Physics and Astronomy, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218 (United States)

    2004-03-24

    This paper explores the large-S route to quantum disorder in the Heisenberg antiferromagnet on the pyrochlore lattice and its homologues in lower dimensions. It is shown that zero-point fluctuations of spins shape up a valence-bond solid at low temperatures for one two-dimensional lattice and a liquid with very short-range valence-bond correlations for another. A one-dimensional model demonstrates potential significance of quantum interference effects (as in Haldane's gap): the quantum melting of a valence-bond order yields different valence-bond liquids for integer and half-integer values of S.

  11. Progress on large area GEMs

    Science.gov (United States)

    Duarte Pinto, S.; Villa, M.; Alfonsi, M.; Brock, I.; Croci, G.; David, E.; de Oliveira, R.; Ropelewski, L.; van Stenis, M.

    2009-12-01

    In 2008, a triple GEM detector prototype with an area of ~ 2000 cm2 has been constructed, based on foils of 66 × 66 cm. GEMs of such dimensions had not been made before, and innovations to the existing technology were introduced to build this detector. This paper discusses these innovations and presents further work on large area GEM development. A single-mask technique overcomes the cumbersome practice of alignment of two masks, which limits the achievable lateral size. The holes obtained with this technique are conical, and have a so-called rim, a small insulating clearance around the hole in the substrate. Further refinements of this technique allow greater control over the shape of holes and the size of rims. Also, an improvement in homogeneity over large areas is expected. Simulation studies have been done to examine the effect of hole shape on the behavior of GEMs. Such studies can help understanding how to use new enhancements of the technique to optimize performance. Many potential applications for large area GEMs foresee large production volumes. Production issues have been studied, and single-mask GEMs turn out to be much more suitable for large scale production than standard GEMs.

  12. Assessment of large aperture scintillometry for large-area surface ...

    Indian Academy of Sciences (India)

    Abhishek Danodia

    2017-07-19

    Jul 19, 2017 ... This study defines that large aperture scintillometer is robust instrument which can evaluate energy flux over a ... conducted to use in crop simulation modelling, developing of new model with calibration and validation of remote sensing .... The design of scintillometer was made by Ochs and Wilson (1993) ...

  13. Preparation of large monodisperse vesicles.

    Directory of Open Access Journals (Sweden)

    Ting F Zhu

    Full Text Available Preparation of monodisperse vesicles is important both for research purposes and for practical applications. While the extrusion of vesicles through small pores (approximately 100 nm in diameter results in relatively uniform populations of vesicles, extrusion to larger sizes results in very heterogeneous populations of vesicles. Here we report a simple method for preparing large monodisperse multilamellar vesicles through a combination of extrusion and large-pore dialysis. For example, extrusion of polydisperse vesicles through 5-microm-diameter pores eliminates vesicles larger than 5 microm in diameter. Dialysis of extruded vesicles against 3-microm-pore-size polycarbonate membranes eliminates vesicles smaller than 3 microm in diameter, leaving behind a population of monodisperse vesicles with a mean diameter of approximately 4 microm. The simplicity of this method makes it an effective tool for laboratory vesicle preparation with potential applications in preparing large monodisperse liposomes for drug delivery.

  14. Assembling large, complex environmental metagenomes

    Energy Technology Data Exchange (ETDEWEB)

    Howe, A. C. [Michigan State Univ., East Lansing, MI (United States). Microbiology and Molecular Genetics, Plant Soil and Microbial Sciences; Jansson, J. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Malfatti, S. A. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Tringe, S. G. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Tiedje, J. M. [Michigan State Univ., East Lansing, MI (United States). Microbiology and Molecular Genetics, Plant Soil and Microbial Sciences; Brown, C. T. [Michigan State Univ., East Lansing, MI (United States). Microbiology and Molecular Genetics, Computer Science and Engineering

    2012-12-28

    The large volumes of sequencing data required to sample complex environments deeply pose new challenges to sequence analysis approaches. De novo metagenomic assembly effectively reduces the total amount of data to be analyzed but requires significant computational resources. We apply two pre-assembly filtering approaches, digital normalization and partitioning, to make large metagenome assemblies more computationaly tractable. Using a human gut mock community dataset, we demonstrate that these methods result in assemblies nearly identical to assemblies from unprocessed data. We then assemble two large soil metagenomes from matched Iowa corn and native prairie soils. The predicted functional content and phylogenetic origin of the assembled contigs indicate significant taxonomic differences despite similar function. The assembly strategies presented are generic and can be extended to any metagenome; full source code is freely available under a BSD license.

  15. Does Yellowstone need large fires

    Energy Technology Data Exchange (ETDEWEB)

    Romme, W.H. (Fort Lewis College, Durango, CO (United States)); Turner, M.G.; Gardner, R.H.; Hargrove, W.W. (Oak Ridge National Laboratory, TN (United States))

    1994-06-01

    This paper synthesizes several studies initiated after the 1988 Yellowstone fires, to address the question whether the ecological effects of large fires differ qualitatively as well as quantitatively from small fires. Large burn patches had greater dominance and contagion of burn severity classes, and a higher proportion of crown fire. Burned aspen stands resprouted vigorously over an extensive area, but heavy ungulate browsing prevented establishment of new tree-sized stems. A burst of sexual reproduction occurred in forest herbs that usually reproduce vegetatively, and new aspen clones became established from seed - a rare event in this region. We conclude that the effects of large fires are qualitatively different, but less dramatically so than expected.

  16. Structuring very large domain models

    DEFF Research Database (Denmark)

    Störrle, Harald

    2010-01-01

    at a lower level of detail have not been dealt with. This paper aims at filling this gap by reporting personal experiences from a very large scale industrial domain modeling project. There, structuring the logical view turned out to be a critical success factor. We explain the project and its setting......, analyze the role and repercussions of model structuring, and examine the implications model structuring decisions have on other parts of the project. We then explain the model structure abstracted from a very large scale industrial modeling project. Finally, we discuss lessons learned....

  17. Preconditioning Large Indefinite Linear Systems

    Directory of Open Access Journals (Sweden)

    Giovanni Fasano

    2011-04-01

    Full Text Available After briefly recalling some relevant approaches for preconditioning large symmetric linear systems, we describe a novel class of preconditioners. Our proposal is tailored for large indefinite linear systems, which arise very frequently in many different contexts of numerical analysis and nonlinear optimization. Our preconditioners are built as a byproduct of the Krylov subspace method used to solve the system. We describe theoretical properties of the proposed class of preconditioners, namely their capability of both shifting some eigenvalues of the system’s matrix to controlled values, and reducing the modulus of the other ones. The results of a numerical experimentation give evidence of the good performance of our proposal.

  18. Dijets at large rapidity intervals

    CERN Document Server

    Pope, B G

    2001-01-01

    Inclusive diet production at large pseudorapidity intervals ( Delta eta ) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large Delta eta in pp collisions at square root s = 1800 and 630 GeV using the DOE detector. The partonic cross section increases strongly with the size of Delta eta . The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alpha /sub BFKL/(20 GeV) = 1.65 +or- 0.07.

  19. Large superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Magnusson, Niklas; Jensen, Bogi Bech

    2012-01-01

    To realize large (>10 MW) direct-driven off-shore wind turbines, a number of steps are needed to reduce weight and cost compared to on-shore technologies. One of the major challenges is to provide drive trains which can comply with the large torque as the turbine rotor diameter is scaled up...... and thereby having a smaller size and weight [1, 2]. A 5 MW superconducting wind turbine generator forms the basics for the feasibility considerations, particularly for the YBCO and MgB2 superconductors entering the commercial market. Initial results indicate that a 5 MW generator with an active weight of 34...

  20. Measurement and modeling of advanced coal conversion processes, Volume I, Part 2. Final report, September 1986--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G. [and others

    1995-09-01

    This report describes work pertaining to the development of models for coal gasification and combustion processes. This volume, volume 1, part 2, contains research progress in the areas of large particle oxidation at high temperatures, large particle, thick-bed submodels, sulfur oxide/nitrogen oxides submodels, and comprehensive model development and evaluation.

  1. Inconsistency in large pharmacogenomic studies

    DEFF Research Database (Denmark)

    Haibe-Kains, Benjamin; El-Hachem, Nehme; Birkbak, Nicolai Juul

    2013-01-01

    Two large-scale pharmacogenomic studies were published recently in this journal. Genomic data are well correlated between studies; however, the measured drug response data are highly discordant. Although the source of inconsistencies remains uncertain, it has potential implications for using thes...... these outcome measures to assess gene-drug associations or select potential anticancer drugs on the basis of their reported results....

  2. Adding large EM stack support

    KAUST Repository

    Holst, Glendon

    2016-12-01

    Serial section electron microscopy (SSEM) image stacks generated using high throughput microscopy techniques are an integral tool for investigating brain connectivity and cell morphology. FIB or 3View scanning electron microscopes easily generate gigabytes of data. In order to produce analyzable 3D dataset from the imaged volumes, efficient and reliable image segmentation is crucial. Classical manual approaches to segmentation are time consuming and labour intensive. Semiautomatic seeded watershed segmentation algorithms, such as those implemented by ilastik image processing software, are a very powerful alternative, substantially speeding up segmentation times. We have used ilastik effectively for small EM stacks – on a laptop, no less; however, ilastik was unable to carve the large EM stacks we needed to segment because its memory requirements grew too large – even for the biggest workstations we had available. For this reason, we refactored the carving module of ilastik to scale it up to large EM stacks on large workstations, and tested its efficiency. We modified the carving module, building on existing blockwise processing functionality to process data in manageable chunks that can fit within RAM (main memory). We review this refactoring work, highlighting the software architecture, design choices, modifications, and issues encountered.

  3. Physics with large extra dimensions

    Indian Academy of Sciences (India)

    Early motivation for large extra dimensions. Attempts to construct a consistent theory for quantum gravity have led only to one candidate: the string theory. The only vacuum of string theory free of any pathologies are supersymmetric. Not being observed in nature, supersymmetry should be broken. In contrast to ordinary ...

  4. Inflating with Large Effective Fields

    CERN Document Server

    Burgess, C P; Quevedo, F; Williams, M

    2014-01-01

    We re-examine large scalar fields within effective field theory, in particular focussing on the issues raised by their use in inflationary models (as suggested by BICEP2 to obtain primordial tensor modes). We argue that when the large-field and low-energy regimes coincide the scalar dynamics is most effectively described in terms of an asymptotic large-field expansion whose form can be dictated by approximate symmetries, which also help control the size of quantum corrections. We discuss several possible symmetries that can achieve this, including pseudo-Goldstone inflatons characterized by a coset $G/H$ (based on abelian and non-abelian, compact and non-compact symmetries), as well as symmetries that are intrinsically higher dimensional. Besides the usual trigonometric potentials of Natural Inflation we also find in this way simple {\\em large-field} power laws (like $V \\propto \\phi^2$) and exponential potentials, $V(\\phi) = \\sum_{k} V_k \\; e^{-k \\phi/M}$. Both of these can describe the data well and give slo...

  5. Energy conservation in large buildings

    Science.gov (United States)

    Rosenfeld, A.; Hafemeister, D.

    1985-11-01

    As energy prices rise, newly energy aware designers use better tools and technology to create energy efficient buildings. Thus the U.S. office stock (average age 20 years) uses 250 kBTU/ft2 of resource energy, but the guzzler of 1972 uses 500 (up×2), and the 1986 ASHRAE standards call for 100-125 (less than 25% of their 1972 ancestors). Surprisingly, the first real cost of these efficient buildings has not risen since 1972. Scaling laws are used to calculate heat gains and losses of buildings to obtain the ΔT(free) which can be as large as 15-30 °C (30-60 °F) for large buildings. The net thermal demand and thermal time constants are determined for the Swedish Thermodeck buildings which need essentially no heat in the winter and no chillers in summer. The BECA and other data bases for large buildings are discussed. Off-peak cooling for large buildings is analyzed in terms of saving peak-electrical power. By downsizing chillers and using cheaper, off-peak power, cost-effective thermal storage in new commercial buildings can reduce U.S. peak power demands by 10-20 GW in 15 years. A further potential of about 40 GW is available from adopting partial thermal storage and more efficient air conditioners in existing buildings.

  6. Large program implementation on minicomputers

    CERN Document Server

    Fonti, L

    1980-01-01

    A method is described to fit a very large program (usually executed on very big mainframes, like a CDC 7600 or IBM 370/168) on a 16-bit minicomputer with memory management support. The method outlined is fully general, even if references are made to a specific example: the implementation of the CERN program HYDRA on a PDP 11/70. (2 refs).

  7. Physics with large extra dimensions

    Indian Academy of Sciences (India)

    The recent understanding of string theory opens the possibility that the string scale can be as low as a few TeV. The apparent weakness of gravitational interactions can then be accounted by the existence of large internal dimensions, in the sub-millimeter region. Furthermore, our world must be confined to live on a brane ...

  8. Large Hadron Collider nears completion

    CERN Multimedia

    2008-01-01

    Installation of the final component of the Large Hadron Collider particle accelerator is under way along the Franco-Swiss border near Geneva, Switzerland. When completed this summer, the LHC will be the world's largest and most complex scientific instrument. It is being constructed by the European Organization for Nuclear Research, one of the world's largest particle physics laboratories.

  9. The very large hadron collider

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This paper reviews the purposes to be served by a very large hadron collider and the organization and coordination of efforts to bring it about. There is some discussion of magnet requirements and R&D and the suitability of the Fermilab site.

  10. Large-scale pool fires

    Directory of Open Access Journals (Sweden)

    Steinhaus Thomas

    2007-01-01

    Full Text Available A review of research into the burning behavior of large pool fires and fuel spill fires is presented. The features which distinguish such fires from smaller pool fires are mainly associated with the fire dynamics at low source Froude numbers and the radiative interaction with the fire source. In hydrocarbon fires, higher soot levels at increased diameters result in radiation blockage effects around the perimeter of large fire plumes; this yields lower emissive powers and a drastic reduction in the radiative loss fraction; whilst there are simplifying factors with these phenomena, arising from the fact that soot yield can saturate, there are other complications deriving from the intermittency of the behavior, with luminous regions of efficient combustion appearing randomly in the outer surface of the fire according the turbulent fluctuations in the fire plume. Knowledge of the fluid flow instabilities, which lead to the formation of large eddies, is also key to understanding the behavior of large-scale fires. Here modeling tools can be effectively exploited in order to investigate the fluid flow phenomena, including RANS- and LES-based computational fluid dynamics codes. The latter are well-suited to representation of the turbulent motions, but a number of challenges remain with their practical application. Massively-parallel computational resources are likely to be necessary in order to be able to adequately address the complex coupled phenomena to the level of detail that is necessary.

  11. Large Scale Glazed Concrete Panels

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    and finally Lene Tranberg and Bøje Lungård’s Elsinore water purification plant. These buildings have qualities that I would like applied, perhaps transformed or most preferably, if possible, interpreted anew, for the large glazed concrete panels I shall develop. The article is ended and concluded...

  12. Large N Expansion. Vector Models

    OpenAIRE

    Nissimov, Emil; Pacheva, Svetlana

    2006-01-01

    Preliminary version of a contribution to the "Quantum Field Theory. Non-Perturbative QFT" topical area of "Modern Encyclopedia of Mathematical Physics" (SELECTA), eds. Aref'eva I, and Sternheimer D, Springer (2007). Consists of two parts - "main article" (Large N Expansion. Vector Models) and a "brief article" (BPHZL Renormalization).

  13. The physics of large eruptions

    Science.gov (United States)

    Gudmundsson, Agust

    2015-04-01

    Based on eruptive volumes, eruptions can be classified as follows: small if the volumes are from less than 0.001 km3 to 0.1 km3, moderate if the volumes are from 0.1 to 10 km3, and large if the volumes are from 10 km3 to 1000 km3 or larger. The largest known explosive and effusive eruptions have eruptive volumes of 4000-5000 km3. The physics of small to moderate eruptions is reasonably well understood. For a typical mafic magma chamber in a crust that behaves as elastic, about 0.1% of the magma leaves the chamber (erupted and injected as a dyke) during rupture and eruption. Similarly, for a typical felsic magma chamber, the eruptive/injected volume during rupture and eruption is about 4%. To provide small to moderate eruptions, chamber volumes of the order of several tens to several hundred cubic kilometres would be needed. Shallow crustal chambers of these sizes are common, and deep-crustal and upper-mantle reservoirs of thousands of cubic kilometres exist. Thus, elastic and poro-elastic chambers of typical volumes can account for small to moderate eruptive volumes. When the eruptions become large, with volumes of tens or hundreds of cubic kilometres or more, an ordinary poro-elastic mechanism can no longer explain the eruptive volumes. The required sizes of the magma chambers and reservoirs to explain such volumes are simply too large to be plausible. Here I propose that the mechanics of large eruptions is fundamentally different from that of small to moderate eruptions. More specifically, I suggest that all large eruptions derive their magmas from chambers and reservoirs whose total cavity-volumes are mechanically reduced very much during the eruption. There are two mechanisms by which chamber/reservoir cavity-volumes can be reduced rapidly so as to squeeze out much of, or all, their magmas. One is piston-like caldera collapse. The other is graben subsidence. During large slip on the ring-faults/graben-faults the associated chamber/reservoir shrinks in volume

  14. Combustion Behaviour of Pulverised Wood - Numerical and Experimental Studies. Part 1 Numerical Study

    Energy Technology Data Exchange (ETDEWEB)

    Elfasakhany, A.; Xue-Song Bai [Lund Inst. of Tech. (Sweden). Dept. of Heat and Power Engineering

    2002-12-01

    This report describes a theoretical/numerical investigation of the particle motion and the particle drying, pyrolysis, oxidation of volatile and char in a pulverised biofuel (wood) flame. This work, along with the experimental measurement of a pulverised wood flame in a vertical furnace at TPS, is supported by the Swedish Energy Agency, STEM. The fundamental combustion process of a pulverised wood flame with determined size distribution and anisotropy character is studied. Comprehensive submodels are studied and some models not available in the literature are developed. The submodels are integrated to a CFD code, previously developed at LTH. The numerical code is used to simulate the experimental flame carried out at TPS (as sub-task 2 within the project). The sub-models describe the drying, devolatilization, char formation of wood particles, and the oxidation reaction of char and the gas phase volatile. At the present stage, the attention is focused on the understanding and modelling of non-spherical particle dynamics and the drying, pyrolysis, and oxidation of volatile and char. Validation of the sub-models against the experimental data is presented and discussed in this study. The influence of different factors on the pulverised wood flame in the TPS vertical furnace is investigated. This includes shape of the particles, the effect of volatile release, as well as the orientation of the particles on the motion of the particles. The effect of particle size on the flame structure (distribution of species and temperature along the axis of the furnace) is also studied. The numerical simulation is in close agreement with the TPS experimental data in the concentrations of species O{sub 2}, CO{sub 2} as well as temperature. Some discrepancy between the model simulations and measurements is observed, which suggests that further improvement in our understanding and modeling the pulverised wood flame is needed.

  15. How large is large? Identifying large corporate ownerships in FIA datasets

    Science.gov (United States)

    Jesse Caputo; Brett Butler; Andy. Hartsell

    2017-01-01

    Forest ownership size is a continuous variable, albeit one with a distinctly nonnormal distribution. Although large corporate forest ownerships are expected to differ in terms of behavior and objectives from smaller corporate ownerships, there is no clear and unambiguous means of defined these two ownership groups. We examined the distribution of the ownership size...

  16. Large-area aircraft scanner

    Science.gov (United States)

    Iddings, Frank A.

    A program to determine the feasibility of present state-of-the-art NDI technology to produce a large-area scanner and to identify commercial equipment available to construct the desired system is presented. Work performed to attain these objectives is described, along with suggested modifications to the existing commercial equipment in order to meet the design criteria as closely as possible. Techniques that show the most promise at present are: D-sight, shearography, and pulse IR thermography (PIRT). D-sight is argued to be inadequate alone, but may well help form a system in conjunction with another technique. Shearography requires additional development in the area of stress application along with interpretation and overall application. PIRT is argued to be satisfactory as a large-area scanner system, at least for thin composite and metal panels.

  17. Chunking of Large Multidimensional Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rotem, Doron; Otoo, Ekow J.; Seshadri, Sridhar

    2007-02-28

    Data intensive scientific computations as well on-lineanalytical processing applications as are done on very large datasetsthat are modeled as k-dimensional arrays. The storage organization ofsuch arrays on disks is done by partitioning the large global array intofixed size hyper-rectangular sub-arrays called chunks or tiles that formthe units of data transfer between disk and memory. Typical queriesinvolve the retrieval of sub-arrays in a manner that accesses all chunksthat overlap the query results. An important metric of the storageefficiency is the expected number of chunks retrieved over all suchqueries. The question that immediately arises is "what shapes of arraychunks give the minimum expected number of chunks over a query workload?"In this paper we develop two probabilistic mathematical models of theproblem and provide exact solutions using steepest descent and geometricprogramming methods. Experimental results, using synthetic workloads onreal life data sets, show that our chunking is much more efficient thanthe existing approximate solutions.

  18. The Large Hadron Collider project

    CERN Document Server

    Engelen, Joseph J

    2005-01-01

    The Large Hadron Collider (LHC) will enable proton-proton collisions at an energy of more than fourteen thousand times the proton mass. This allows the discovery of new elementary particles with very large masses, in particular of the Higgs boson. The Higgs boson is crucial for understanding the mechanism that Nature chose to give mass to particles. The Higgs boson has turned out to be very hard to find but the LHC should allow a decisive step into new territory, unveiling one or even more Higgs bosons. The new energy domain of the LHC also inspires speculations about discoveries relevant for understanding dark matter and about the discovery of new space dimensions, so far hidden to us. In the talk an overview of the physics at LHC and a report on the status of the project, accelerator and experiments, will be presented.

  19. Physics with large extra dimensions

    CERN Document Server

    Antoniadis, Ignatios

    2004-01-01

    The recent understanding of string theory opens the possibility that the string scale can be as low as a few TeV. The apparent weakness of gravitational interactions can then be accounted by the existence of large internal dimensions, in the submillimeter region. Furthermore, our world must be confined to live on a brane transverse to these large dimensions, with which it interacts only gravitationally. In my lecture, I describe briefly this scenario which gives a new theoretical framework for solving the gauge hierarchy problem and the unification of all interactions. I also discuss its main properties and implications for observations at both future particle colliders, and in non-accelerator gravity experiments. Such e®ects are for instance the production of Kaluza-Klein resonances, graviton emission in the bulk of extra dimensions, and a radical change of gravitational forces in the submillimeter range.

  20. Physics with large extra dimensions

    CERN Document Server

    Antoniadis, Ignatios

    2004-01-01

    The recent understanding of string theory opens the possibility that the string scale can be as low as a few TeV. The apparent weakness of gravitational interactions can then be accounted by the existence of large internal dimensions, in the submillimeter region. Furthermore, our world must be confined to live on a brane transverse to these large dimensions, with which it interacts only gravitationally. In my lecture, I describe briefly this scenario which gives a new theoretical framework for solving the gauge hierarchy problem and the unification of all interactions. I also discuss its main properties and implications for observations at both future particle colliders, and in non-accelerator gravity experiments. Such effects are for instance the production of Kaluza-Klein resonances, graviton emission in the bulk of extra dimensions, and a radical change of gravitational forces in the submillimeter range.