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1

Uptake of arsenic by alkaline soils near alkaline coal fly ash disposal facilities.  

UK PubMed Central (United Kingdom)

The attenuation of arsenic in groundwater near alkaline coal fly ash disposal facilities was evaluated by determining the uptake of arsenic from ash leachates by surrounding alkaline soils. Ten different alkaline soils near a retired coal fly ash impoundment were used in this study with pH ranging from 7.6 to 9.0, while representative coal fly ash samples from two different locations in the coal fly ash impoundment were used to produce two alkaline ash leachates with pH 7.4 and 8.2. The arsenic found in the ash leachates was present as arsenate [As(V)]. Adsorption isotherm experiments were carried out to determine the adsorption parameters required for predicting the uptake of arsenic from the ash leachates. For all soils and leachates, the adsorption of arsenic followed the Langmuir and Freundlich equations, indicative of the favorable adsorption of arsenic from leachates onto all soils. The uptake of arsenic was evaluated as a function of ash leachate characteristics and the soil components. The uptake of arsenic from alkaline ash leachates, which occurred mainly as calcium hydrogen arsenate, increased with increasing clay fraction of soil and with increasing soil organic matter of the alkaline soils. Appreciable uptake of arsenic from alkaline ash leachates with different pH and arsenic concentration was observed for the alkaline soils, thus attenuating the contamination of groundwater downstream of the retired coal fly ash impoundment.

Khodadoust AP; Theis TL; Murarka IP; Naithani P; Babaeivelni K

2013-07-01

2

Nitrogen mineralization from sludge in an alkaline, saline coal gasification ash environment.  

Science.gov (United States)

Rehabilitating coal gasification ash dumps by amendment with waste-activated sludge has been shown to improve the physical and chemical properties of ash and to facilitate the establishment of vegetation. However, mineralization of organic N from sludge in such an alkaline and saline medium and the effect that ash weathering has on the process are poorly understood and need to be ascertained to make decisions regarding the suitability of this rehabilitation option. This study investigated the rate and pattern of N mineralization from sludge in a coal gasification ash medium to determine the prevalent inorganic N form in the system and assess the effect of ash weathering on N mineralization. An incubation experiment was performed in which fresh ash, weathered ash, and soil were amended with the equivalent of 90 Mg ha sludge, and N mineralization was evaluated over 63 d. More N (24%) was mineralized in fresh ash than in weathered ash and soil, both of which mineralized 15% of the initial organic N in sludge. More nitrification occurred in soil, and most of the N mineralized in ash was in the form of ammonium, indicating an inhibition of nitrifying organisms in the ash medium and suggesting that, at least initially, plants used for rehabilitation of coal gasification ash dumps will take up N mostly as ammonium. PMID:23673951

Mbakwe, Ikenna; De Jager, Pieter C; Annandale, John G; Matema, Taurai

3

Nitrogen mineralization from sludge in an alkaline, saline coal gasification ash environment.  

UK PubMed Central (United Kingdom)

Rehabilitating coal gasification ash dumps by amendment with waste-activated sludge has been shown to improve the physical and chemical properties of ash and to facilitate the establishment of vegetation. However, mineralization of organic N from sludge in such an alkaline and saline medium and the effect that ash weathering has on the process are poorly understood and need to be ascertained to make decisions regarding the suitability of this rehabilitation option. This study investigated the rate and pattern of N mineralization from sludge in a coal gasification ash medium to determine the prevalent inorganic N form in the system and assess the effect of ash weathering on N mineralization. An incubation experiment was performed in which fresh ash, weathered ash, and soil were amended with the equivalent of 90 Mg ha sludge, and N mineralization was evaluated over 63 d. More N (24%) was mineralized in fresh ash than in weathered ash and soil, both of which mineralized 15% of the initial organic N in sludge. More nitrification occurred in soil, and most of the N mineralized in ash was in the form of ammonium, indicating an inhibition of nitrifying organisms in the ash medium and suggesting that, at least initially, plants used for rehabilitation of coal gasification ash dumps will take up N mostly as ammonium.

Mbakwe I; De Jager PC; Annandale JG; Matema T

2013-05-01

4

Toxicity mitigation and solidification of municipal solid waste incinerator fly ash using alkaline activated coal ash.  

UK PubMed Central (United Kingdom)

Municipal solid waste (MSW) incineration is a common and effective practice to reduce the volume of solid waste in urban areas. However, the byproduct of this process is a fly ash (IFA), which contains large quantities of toxic contaminants. The purpose of this research study was to analyze the chemical, physical and mechanical behaviors resulting from the gradual introduction of IFA to an alkaline activated coal fly ash (CFA) matrix, as a mean of stabilizing the incinerator ash for use in industrial construction applications, where human exposure potential is limited. IFA and CFA were analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD) and Inductive coupled plasma (ICP) to obtain a full chemical analysis of the samples, its crystallographic characteristics and a detailed count of the eight heavy metals contemplated in US Title 40 of the Code of Federal Regulations (40 CFR). The particle size distribution of IFA and CFA was also recorded. EPA's Toxicity Characteristic Leaching Procedure (TCLP) was followed to monitor the leachability of the contaminants before and after the activation. Also images obtained via Scanning Electron Microscopy (SEM), before and after the activation, are presented. Concrete made from IFA, CFA and IFA-CFA mixes was subjected to a full mechanical characterization; tests include compressive strength, flexural strength, elastic modulus, Poisson's ratio and setting time. The leachable heavy metal contents (except for Se) were below the maximum allowable limits and in many cases even below the reporting limit. The leachable Chromium was reduced from 0.153 down to 0.0045 mg/L, Arsenic from 0.256 down to 0.132 mg/L, Selenium from 1.05 down to 0.29 mg/L, Silver from 0.011 down to .001 mg/L, Barium from 2.06 down to 0.314 mg/L and Mercury from 0.007 down to 0.001 mg/L. Although the leachable Cd exhibited an increase from 0.49 up to 0.805 mg/L and Pd from 0.002 up to 0.029 mg/L, these were well below the maximum limits of 1.00 and 5.00 mg/L, respectively.

Diaz-Loya EI; Allouche EN; Eklund S; Joshi AR; Kupwade-Patil K

2012-08-01

5

Injection of alkaline ashes into underground coal mines for acid mine drainage abatement  

International Nuclear Information System (INIS)

The injection of alkaline coal combustion waste products into abandoned underground coal mines for acid mine drainage (AMD) abatement has obvious conceptual appeal. This paper summarizes the findings of the baseline hydrogeologic and water quality evaluations at two sites--one in West Virginia and one in Maryland--where field demonstrations of the technique are being pursued in cooperative efforts among State and Federal agencies and/or private companies. The West Virginia site produces severe AMD from three to seven AMD sources that are spaced over about a 1.2 km stretch of the down-dip side of the mine workings. By completely filling the most problematic portion of the mine workings with coal combustion ashes, the State expects that the costs and problems associated with AMD treatment will be greatly reduced. At the Maryland site, it is expected that the AMD from a relatively small target mine will be eliminated completely by filling the entire mine void with a grout composed of a mixture of fly ash, fluidized-bed combustion ash, and flue gas desulfurization sludge. This project will also demonstrate the potential cost-effectiveness of the technique at other sites, both for the purpose of AMD remediation and control of land subsidence.

1996-01-01

6

Alkaline coal fly ash amendments are recommended for improving rice-peanut crops  

Energy Technology Data Exchange (ETDEWEB)

A field experiment investigating amendments of organic material including farmyard manure, paper factory sludge and crop residues combined with fly ash, lime and chemical fertilizer in a rice-peanut cropping system was conducted during 1997-98 and 1998-99 at the Indian Institute of Technology, Kharagpur, India. The soil was an acid lateritic (Halustaf) sandy loam. For rice, an N:P:K level of 90:26.2:33.3 kg/ha was supplied through the organic materials and chemical fertilizer to all the treatments except control and fly ash alone. The required quantities of organic materials were added to supply 30 kg N/ha and the balance amount of N, P and K was supplied through chemical fertilizer. Amendment materials as per fertilization treatments were incorporated to individual plots 15 days before planting of rice during the rainy season. The residual effects were studied on the following peanut crop with application of N:P:K at 30:26.2:33.3 kg/ha through chemical fertilizer alone in all treatments, apart from the control. An application of fly ash at 10 t/ha in combination with chemical fertilizer and organic materials increased the grain yield of rice by 11% compared to chemical fertilizer alone. The residual effect of both lime and fly ash applications combined with direct application of chemical fertilizer increased peanut yields by 30% and 24%, respectively, compared to chemical fertilizer alone. Treatments with fly ash or lime increased P and K uptake in both the crops and oil content in peanut kernel compared to those without the amendments. Alkaline coal fly ash proved to be a better amendment than lime for improving productivity of an acid lateritic soil and enriching the soil with P and K.

Swain, D.K.; Ghosh, B.C. [Agricultural and Food Engineering Department, Indi an Inst. of Technology, Kharagpur, West Bengal (India); Rautaray, S.K. [RRLRRS, Gerua Via-Hajo, Dist-Kamrup, Assam (India)

2007-05-15

7

Alkaline hydrothermal de-ashing and desulfurization of low quality coal and its application to hydrogen-rich gas generation  

International Nuclear Information System (INIS)

This paper describes experimental research and a fundamental study of alkaline hydrothermal treatment of high-sulfur, high-ash coal from Banten, Java-Indonesia. Experiments were carried out on a laboratory-scale 0.5 L batch reactor. The alkaline hydrothermal treatment gave upgraded clean coal with low sulfur content (about 0.3 wt.%) and low ash content (about 2.1 wt.%). A zero carbon dioxide and pure hydrogen gas were produced at 330 oC by introducing an alkali (sodium hydroxide, NaOH) to the hydrothermal treatment of raw coal. X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were used to test for the removal or reduction of major inorganic elements in the coal, and changes in carbon-functional groups and their properties were determined by Fourier transform infrared spectroscopy (FTIR) and Carbon-13 of nuclear magnetic resonance (13C NMR) tests on the product of the hydrothermal upgrading and demineralization process.

2011-01-01

8

Environmental risks of farmed and barren alkaline coal ash landfills in Tuzla, Bosnia and Herzegovina  

International Nuclear Information System (INIS)

The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH (?12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were -1 whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44 ?g l-1). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR. - Uncontrolled farming and tillage of previously soil-covered coal ash landfills resulted in exposure of ash on the surface.

2008-01-01

9

Processes controlling the variations of pH, alkalinity, and CO2 partial pressure in the porewater of coal ash disposal site  

International Nuclear Information System (INIS)

Alkalinity, pH, and pCO2 are generally regarded as the most important parameters affecting trace element leaching from coal ashes. However, little is known about how those parameters are actually regulated in the field condition. This study investigated the processes controlling those parameters by observing undisturbed porewater chemistry in a closed ash disposal site. The site is now covered with 30-50 cm thick soils according to the management scheme suggested by the Waste Management Law of Korea and our results show the important role of soil cover regulating those parameters in the shallow porewater. Without the soil cover, the shallow porewater shows low pCO2 and alkalinity, and highly alkaline pH. In contrast, the porewater shows much higher alkalinity and near neutral pH range when the site was covered with the low permeability soils. This difference was caused by the CO2 supply condition changes associated with the changes in infiltration rate. The geochemical modeling shows that the calcite precipitations induced by porewater aging, dolomitization, and weathering of solid phases are the main processes controlling alkalinity, pH, and pCO2 in the deep saline porewaters. The weathering of coal ash plays the most important role decreasing the alkalinity in the deep porewater.

2010-09-15

10

Steam gasification of German hard coal using alkaline catalysts: effects of carbon burn-off and ash content  

Energy Technology Data Exchange (ETDEWEB)

Laboratory-scale experiments were performed on chars from German hard coals with potassium carbonate addition. The steam gasification rate at 4 megapascals and 700 C as a function of the amount of catalyst added is described for low- and high-ash char. From the burn-off behaviour the reaction order relative to carbon was determined. For the low-ash char a uniform reaction order was found but the high-ash char indicated a complex interaction of catalytic gasification, catalyst deactivation, and the development of the reacting surface.

Leonhardt, P.; Sulimma, A.; van Heek, K.H.; Juentgen, H.

1983-02-01

11

Processing of coal ash leachate  

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the processing of the coal ash leachate produced in the course of treating coal ash by a combination of water and acid leaching. In wet magnetic separation experiments in which 6.7-14.5 wt% of the test material was retained by the magnet, the leachate contained Ca, Na and K. Only negligible amounts of other elements were eluted. Small quantities of heavy metals were eluted by using dilute hydrochloric acid to leach the material which was not retained by the magnet. Finally, coal ash leachate processing experiments were carried out in which the alkaline leachate obtained by water leaching was gradually added to the acid leachate. This procedure enabled Al, Fe and Cr to be precipitated and removed. Elements such as Ca, Na, K, Cu and Cd remained in solution, while elements such as Mg, Zn and Si were partially separable by precipitation. 6 references.

Ichijoh, M.; Hamada, Y.; Ohsaki, K.; Katoh, S.; Tamakawa, T.; Rokugawa, N.; Kosuge, K.

1984-01-01

12

Environmental risks of farmed and barren alkaline coal ash landfills in Tuzla, Bosnia and Herzegovina.  

Science.gov (United States)

The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH ( approximately 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were <2microgl(-1) whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44microgl(-1)). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR. PMID:17949870

Dellantonio, Alex; Fitz, Walter J; Custovic, Hamid; Repmann, Frank; Schneider, Bernd U; Grünewald, Holger; Gruber, Valeria; Zgorelec, Zeljka; Zerem, Nijaz; Carter, Claudia; Markovic, Mihajlo; Puschenreiter, Markus; Wenzel, Walter W

2007-10-18

13

Environmental risks of farmed and barren alkaline coal ash landfills in Tuzla, Bosnia and Herzegovina  

Energy Technology Data Exchange (ETDEWEB)

The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH (similar to 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were < 2 {mu} g l{sup -1} whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44 {mu} g l{sup -1}). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.

Dellantonio, A.; Fitz, W.J.; Custovic, H.; Repmann, F.; Schneider, B.U.; Grunewald, H.; Gruber, V.; Zgorelec, Z.; Zerem, N.; Carter, C.; Markovic, M.; Puschenreiter, M.; Wenzel, W.W. [University for Natural Resources & Applied Life Science, Vienna (Austria)

2008-06-15

14

Coal ash utilisation in India  

Energy Technology Data Exchange (ETDEWEB)

The paper describes the possible uses for the coal ash produced by Indian coal fired power stations. Aspects covered include: volume of ash produced in India; physico-chemical and mineralogical characterisation of the coal ash; and fly ash based products and their usefulness. Products include Portland pozzolana cement (PPC), fly ash bricks and fly ash concrete. The economic and technical details of using coal fly ash for PPC and brick production are discussed in some detail. Policies to encourage the utilisation of coal ash are suggested. 9 tabs.

Palit, A. (National Thermal Power Corporation Ltd., New Delhi (India). Research and Development Division)

1992-09-01

15

Ash Microspheres for Coal Burning  

International Science & Technology Center (ISTC)

Estimation of perspectives for ash microspheres production at coal burning thermal power stations , development of methods for their quality certification. Creation of a database for ash microspheres in Russian Federation.

16

Coal ash utilization in India  

Energy Technology Data Exchange (ETDEWEB)

This paper describes methods of coal combustion product (CCP) management successfully employed in the US and considers their potential application in India. India produces about 66 million tons per year (mty) of coal ash from the combustion of 220 mty of domestically produced coal, the average ash content being about 30--40 percent as opposed to an average ash content of less than 10 percent in the US In other words, India produces coal ash at about triple the rate of the US. Currently, 95 percent of this ash is sluiced into slurry ponds, many located near urban centers and consuming vast areas of premium land. Indian coal-fired generating capacity is expected to triple in the next ten years, which will dramatically increase ash production. Advanced coal cleaning technology may help reduce this amount, but not significantly. Currently India utilizes two percent of the CCP`s produced with the remainder being disposed of primarily in large impoundments. The US utilizes about 25 percent of its coal ash with the remainder primarily being disposed of in nearly equal amounts between dry landfills and impoundments. There is an urgent need for India to improve its ash management practice and to develop efficient and environmentally sound disposal procedures as well as high volume ash uses in ash haulback to the coalfields. In addition, utilization should include: reclamation, structural fill, flowable backfill and road base.

Michalski, S.R.; Brendel, G.F.; Gray, R.E. [GAI Consultants, Inc., Pittsburgh, PA (United States)

1998-12-31

17

Measuring ash content of coal  

International Nuclear Information System (INIS)

[en] An apparatus for measuring the ash content of coal is claimed. It comprises a means for irradiating a known quantity of coal in a transport container with a known dose of neutrons, a means for detecting ?-rays having a predetermined energy emitted by the irradiated coal, the ?-rays being indicative of the presence of an ash-forming element in the coal, a means for producing a signal related to the intensity of the ?-ray emission and a means responsive to the signal to provide an indication of the concentration of the ash-forming element in the coal

1979-10-02

18

Measuring ash content of coal  

International Nuclear Information System (INIS)

[en] Apparatus for measuring the ash content of coal is claimed. A neutron source is positioned so as to be capable of irradiating coal in transport containers with a known dose of neutrons. Gamma ray emission indicates the presence of an ash-forming element in the coal. There is a means for detecting the gamma rays, means for producing a signal related to the intensity of the gamma-ray emission and means responsive to this signal to provide an indication of the concentration of the ash-forming element in the coal in each transport container

1978-10-02

19

Coal ash utilisation in India  

International Nuclear Information System (INIS)

Coal based thermal power stations have been the major source of power generation in our country in the past and would continue for decades to come. In India, thermal generation which contributes about 72% of the overall power generation of 2,45,000 MU (1989-90) is the main source of power and mainly based on coal firing. Total ash generation in India presently is to the tune of 38 million tonnes per annum. India is fourth in the world as far as coal ash generation is concerned. USSR is first, (100 million tonnes), then come USA (45 million tonnes) and China (41 million tonnes). The basic problem of thermal power station fired with high ash content coal is the generation of huge quantity of coal ash which would pose serious environmental and other related problems. The present paper analyses the extensive scope of utilisation of coal ash and enlightens the strategies to be adopted to overcome the related problems for proper utilisation of coal ash. (author). 9 tabs.

1992-01-01

20

Classification of pulverized coal ash  

International Nuclear Information System (INIS)

[en] The leachability of fifty different pulverized coal ashes from utilities in the Netherlands, Federal Republic of Germany and Belgium has been studied. Five different ashes were analyzed according to the complete standard leaching test and the results were published earlier. The examination of a wide variety of ashes under a wide range of pH and Liquid to Solid ratio (LS) conditions creates the possibility of identifying systematic trends in fly ash leaching behaviour and to identify the mechanisms controlling release. 16 figs., 2 tabs., 3 app., 25 refs

1992-01-01

 
 
 
 
21

Ash-fusion characteristics of Kentucky coals  

Energy Technology Data Exchange (ETDEWEB)

Ash-fusion characteristics are used to predict the behaviour of coal ash under high-temperature conditions and are a major factor in the marketability of coal and in boiler design. Despite the common application of this test within the coal industry, little has been published on variability in ash-fusion temperatures (AFTs). The objective of this study was to evaluate the variability in ash-fusion characteristics of Kentucky coals. The approach was to establish an extensive ash-fusion data base which can be used in detailed statistical analysis of ash-fusion temperatures and chemical composition of coal ashes for both the Western and Eastern Kentucky Coalfields.

Rimmer, S.M.

1989-01-01

22

Coal ash artificial reef demonstration  

International Nuclear Information System (INIS)

[en] This experimental project evaluated the use of coal ash to construct artificial reefs. An artificial reef consisting of approximately 33 tons of cement-stabilized coal ash blocks was constructed in approximately 20 feet of water in the Gulf of Mexico approximately 9.3 miles west of Cedar Key, Florida. The project objectives were: (1) demonstrate that a durable coal ash/cement block can be manufactured by commercial block-making machines for use in artificial reefs, and (2) evaluate the possibility that a physically stable and environmentally acceptable coal ash/cement block reef can be constructed as a means of expanding recreational and commercial fisheries. The reef was constructed in February 1988 and biological surveys were made at monthly intervals from May 1988 to April 1989. The project provided information regarding: Development of an optimum design mix, block production and reef construction, chemical composition of block leachate, biological colonization of the reef, potential concentration of metals in the food web associated with the reef, acute bioassays (96-hour LC50). The Cedar Key reef was found to be a habitat that was associated with a relatively rich assemblage of plants and animals. The reef did not appear to be a major source of heavy metals to species at various levels of biological organization. GAI Consultants, Inc (GAI) of Monroeville, Pennsylvania was the prime consultant for the project. The biological monitoring surveys and evaluations were performed by Environmental Planning and Analysis, Inc. of Tallahassee, Florida. The chemical analyses of biological organisms and bioassay elutriates were performed by Savannah Laboratories of Tallahassee, Florida. Florida Power Corporation of St. Petersburg, Florida sponsored the project and supplied ash from their Crystal River Energy Complex

1991-01-01

23

COAL ASH RESOURCES RESEARCH CONSORTIUM  

Energy Technology Data Exchange (ETDEWEB)

The Coal Ash Resources Research Consortium (CARRC, pronounced ?cars?) is the core coal combustion by-product (CCB) research group at the Energy & Environmental Research Center (EERC). CARRC focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of CCBs. CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCB utilization and ensuring its successful application. CARRC continued the partnership of industry partners, university researchers, and the U.S. Department of Energy (DOE) addressing needs in the CCB industry through technical research and development projects. Technology transfer also continued through distribution and presentation of the results of research activities to appropriate audiences, with emphasis on reaching government agency representatives and end users of CCBs. CARRC partners have evolved technically and have jointly developed an understanding of the layers of social, regulatory, legal, and competition issues that impact the success of CCB utilization as applies to the CCB industry in general and to individual companies. Many CARRC tasks are designed to provide information on CCB performance including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC activities from 1993?1998 included a variety of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCBs. The tasks summarized in this report are 1) The Demonstration of CCB Use in Small Construction Projects, 2) Application of CCSEM (computer-controlled scanning electron microscopy) for Coal Combustion By-Product Characterization, 3) Development of a Procedure to Determine Heat of Hydration for Coal Combustion By-Products, 4) Investigation of the Behavior of High-Calcium Coal Combustion By-Products, 5) Development of an Environmentally Appropriate Leaching Procedure for Coal Combustion By-Products, 6) Set Time of Fly Ash Concrete, 7) Coal Ash Properties Database (CAPD), 8) Development of a Method for Determination of Radon Hazard in CCBs, 9) Development of Standards and Specifications, 10) Assessment of Fly Ash Variability, and 11) Development of a CCB Utilization Workshop. The primary goal of CARRC is to work with industry to solve CCB-related problems and promote the environmentally safe, technically sound, and economical utilization and disposal of these highly complex materials. CARRC 1993?1998 accomplishments included: C Updating the CAPD to a user-friendly database management system, and distributing it to CARRC members. C ASTM standard preparation for a guide to using CCBs as waste stabilization agents. C Preliminary identification of specific mineral transformations resulting from fly ash hydration. C Limited determination of the effects of fly ash on the set time of concrete. C Statistical evaluation of a select set of fly ashes from several regional coal-fired power plants. C Development and presentation of a workshop on CCB utilization focused on government agency representatives and interested parties with limited CCB utilization experience. C Participation in a variety of local, national, and international technical meetings, symposia, and conferences by presenting and publishing CCB-related papers.

NONE

1998-12-01

24

Greener concrete from wood fly ash and coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted to determine the optimum proportions of using wood fly ash in the production of concrete. Two different sources of wood fly ash and two different sources of ASTM C618 Class C coal fly ash were used to develop two mixtures of non-air entrained concrete. The study included 8 different mixture proportions which were compared with a control mixture without any additive fly ash. Three of the mixtures had 15, 25 and 35 per cent fly ash as partial replacement for portland cement, and four mixtures were made with blends of wood and coal ash at levels of 25 and 35 per cent. The performance of concrete with wood ash was considerably different than the control sample. Blending of wood and coal improved the performance of wood fly ash significantly. It was concluded that structural grade concrete can be made with both wood fly ash and with blended wood-coal fly ash as an admixture to cement. Compressive strengths values were measured to be 40 to 50 MPa at 28 and 91 days. 14 refs., 4 tabs., 4 figs.

Naik, T.R.; Kraus, R.N.; Singh, S.S. [Wisconsin-Milwaukee Univ., Milwaukee, WI (United States); Pennock, L.L. [Wisconsin Public Service Corp., Green Bay, WI (United States); Ramme, B.W. [Wisconsin Electric Power Co., Milwaukee, WI (United States)

2001-07-01

25

Changes in biological parameters during co-composting sewage sludge and coal ash residues  

Energy Technology Data Exchange (ETDEWEB)

Coal ash residues, including fly ash (FA) and lagoon ash (LA), were co-composted with dewatered sludge for 100 days in a bench-scale composting system and biological parameters were monitored to evaluate the effect of ash residues on the composting process. Coal ash residue amendment caused a rise in alkalinity and salinity, but had no adverse effect on the population of the thermophilic bacteria except for 25% FA amendment. All enzyme activities decreased with compositing time. Beta-glucosidase and alkaline phosphatase activities were reduced with an increase in ash residue amendment, while no significant reduction was noted for urease and dehydrogenase activities after 20 days of incubation. The paper shows that with the exception of 25% FA-amended sludge compost, addition of coal ash residues in sewage sludge is feasible, showing little effects on metabolic activity during composting process.

Fang, M.; Wong, J.W.C.; Li, G.X.; Wong, M.H. [Hong Kong Baptist University, Hong Kong (China). Dept. of Biology

1998-04-01

26

Ash fusion study of West Virginia coals  

Energy Technology Data Exchange (ETDEWEB)

As more industries and utilities convert to coal, ash fusion information becomes more important for boiler design (waste disposal systems). For example, burning a low fusion temperature coal can cause slagging - the buildup of molten ash on boiler waterwall tubes. Not only is boiler efficiency lowered, but downtime is also increased. Recently, potential buyers of West Virginia coal have inquired frequently about ash fusion. However, the amount of information in the West Virginia Geological and Economic Survey's data base is limited to data from about 800 samples, 50% of which were collected in five counties. Thus, the survey is conducting a study of ash fusion temperatures for the state's coals, to increase available data and its geographic coverage. A Leco AF-500 automated ash fusion analyzer was used in this study, which addresses: 1) reliability of results from an automated analyzer, 2) comparison of automated data with conventional data, 3) techniques of sample preparation, high-temperature ashing, and cone preparation, 4) ash-fusion trends in the state, and 5) research developments. The research sought to develop for West Virginia coal a statistical correlation model relating ash-elemental data with fusion data, and to investigate the relationship between ash color and fusion temperature. (Light-colored ashes generally have higher fusion temperatures than darker ashes.)

Ashton, K.C., Smith, C.J.; Hohn, M.E.

1984-12-01

27

Mechanical characteristics of FBC coal ash  

Energy Technology Data Exchange (ETDEWEB)

The ash generated in a fluidized bed combustion boiler contains a greater quantity of calcium compounds than ash from a pulverized coal boiler, because of the limestone added to the FBC boiler. Time dependent characteristics of 13 FBC coal ash samples were examined using physical, chemical and dynamic tests, X-ray diffraction analysis and scanning electron microscopy. The results indicated that the density of FBC coal ash contributes to strength of hardening and the free CaO/mixed water ratio affects compressive strength. 5 figs., 20 tabs.

Kamata, H.; Horiuchi, S.; Tai, F.; Hosoda, N.; Teramae, T.; Nagataki, S. (Center for Coal Utilization, Japan, Tokyo (Japan))

1993-01-01

28

A geotechnical classification system for coal ashes  

Energy Technology Data Exchange (ETDEWEB)

Most of the existing soil classification systems make use of the plasticity chart for classifying fine-grained soils and some coarse-grained soils as well. They cannot classify those granular materials that are non-plastic through appropriate group symbols indicative of their non-plastic nature without any ambiguity. Coal ashes, consisting of fly ash (known as pulverised fuel ash in the UK), bottom ash and pond ash, are produced in large quantities and are occasionally used in geotechnical applications. As they are non-plastic materials, the existing classification systems fail to classify them appropriately. This paper discusses this issue in detail. A classification system for coal ashes that are essentially non-plastic is formulated and proposed in this paper. It is shown through illustrative examples that the coal ashes can be classified easily and without any ambiguity using the proposed system.

Prakash, K.; Sridharan, A. [S.J. College of Engineering, Mysore (India). Dept. of Civil Engineering

2006-04-15

29

Pulverised coal ash - requirements for utilisation  

Energy Technology Data Exchange (ETDEWEB)

Coal ash is an inherently variable material due to differences in the mineral content of the source coal, combustion conditions, and ash collection and handling methods. This affects the marketability of pulverised coal ash. Markets in different countries are discussed with respect to opportunities and obstacles to their development. Recent publications on applications for pulverised coal ash are reviewed briefly. A knowledge of the chemical, mineralogical and physical properties of fly ash and bottom ash is essential for the more specialised utilisation sectors such as cement and concrete. Methods for the classification of fly ash are reviewed. Standards and specifications used in various countries for use of coal ash in different applications are discussed along with the appropriate test methods. Quality assurance procedures which suppliers use to ensure fly ash meets these specifications are also included. The marketability of fly ash may be improved by a number of beneficiation processes. Processes such as dewatering, blending, agglomeration, grinding, sieving, air classification, flotation, carbon burnout and electrostatic separation are discussed, including some examples of processes which are being actively developed. 217 refs., 29 figs., 23 tabs.

Sloss, L.S.; Smith, I.M.; Adams, D.M.B.

1996-06-01

30

Trends in the use of coal ash  

Energy Technology Data Exchange (ETDEWEB)

This report investigates the physical and chemical characteristics of coal ash resulting from changing practices in plant operation in response to the demands of environmental regulations. The influence of fuel characteristics is summarised, including the effects of cofiring coal with other materials such as biomass and wastes. Effects due to changes in boiler operation are covered as well as the optimised use of reagents and additives in particulate, SO{sub 2} and NOx emissions control systems to maintain the quality of fly ash. More coal ash can be used if its characteristics meet the standards in the construction industry and it is competitive with conventional materials. Data on the production and use of coal ash in different countries and the discernible trends in the approach to ash use are also summarised. 192 refs., 16 figs., 22 tabs.

Sloss, L.L.

1999-10-01

31

Adding coal ash to the composting mixes  

Energy Technology Data Exchange (ETDEWEB)

Coal ash will be one of the feed-stocks used in a Washington State University program to compost 16,500 tons of material generated annually on the Pullman campus. The university`s power plant generates approximately 1,000 tons of coal ash each year during fall and winter when coal is used as a backup to natural gas. Based on results of a pilot study begun in March, 1993, the ash will be mixed with 10,000 tons of manure and 440 tons of pulped food waste from dining halls. Mixed waste paper and landscape trimmings also will be composted. The pilot study used compost and separated cow manure to determine if composting coal ash would ameliorate storage and application problems. The objectives of the study were to determine the amount of coal ash that could be added to compost piles without compromising biological activity; to monitor the chemical composition of compost with additions of coal ash; and to quantify barley grain yields using coal ash compost. 5 refs., 1 fig., 2 tabs.

Beaver, T. [Washington State University, Pullman, WA (United States). Center for Sustaining Agriculture and Natural Resources

1995-03-01

32

Pulverised coal ash: Requirements for utilisation. Final report  

Energy Technology Data Exchange (ETDEWEB)

Coal ash is an inherently variable material due to differences in the mineral content of the source coal, combustion conditions, and ash collection and handling methods. This affects the marketability of pulverised coal ash. Markets in different countries are discussed with respect to opportunities and obstacles to their development. Recent publications on applications for pulverised coal ash are reviewed briefly. A knowledge of the chemical, mineralogical and physical properties of fly ash and bottom ash are reviewed.

Sloss, L.L.; Smith, I.M.; Adams, D.M.B.

1996-06-01

33

Microbial responses to coal fly ash under field conditions  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ash may be a valuable soil amendment because it contains plant nutrients and liming agents and has a silty texture that can improve the water-holding capacities of sandy, drought-prone soils. Short-term laboratory studies have indicated that addition of unweathered fly ash to soil can stress microbial populations and their activities, but effects of fly ash addition at the field scale are not known. In this study, field plots received 0 or 505 Mg fly ash ha{sup -1} (incorporated by conventional tillage to a depth of 40 cm) and were subsequently cropped to a fallow-corn (Zea mays L.)-wheat (Triticum aestivum L.) rotation or continuous fescue (Festuca arundinacea Schreb.). Twenty months later, during the wheat phase of the rotation, the plots were sampled (0-15 cm) and assayed for activity of soil enzymes (dehydrogenase, alkaline phosphatase, arylsulfatase, and denitrifying enzymes); numbers of aerobic heterotrophs, ammonium oxidizers, denitrifiers, and bradyrhizobia; and N mineralization, nitrification, and denitrification potentials. Nitrification potentials doubled in fly ash-amended soils, and numbers of denitrifiers were 200-fold higher in fescue-cropped, fly ash-amended soils relative to fescue-cropped, non-amended soils. No other large differences in microbial populations or activities were found. The lack of detrimental effects on microorganisms in the field was possibly due to reductions in fly ash`s soluble salt and trace element concentrations with time, the mild alkalinity of the fly ash used in this study, and the positive responses of crops to fly ash amendment. 23 refs., 3 tabs.

Schutter, M.E.; Fuhrmann, J.J. [Oregon State University, Corvallis, OR (United States). Dept. of Crop and Soil Science

1999-03-01

34

West Virginia coal: guide to ash-fusion characteristics  

Energy Technology Data Exchange (ETDEWEB)

Ash-fusion temperatures for coal affect how efficiently and dependably electricity is generated. The wrong ash fusion could seriously impact the coal-fired utility. This report includes information about the coal-fired utility, the importance of ash-fusion temperatures, and a data base of ash-fusion temperature information for West Virginia coal seams. Maps are included that were developed using the data base, which show the variation of ash-fusion temperatures in the West Virginia coal seams.

1986-07-01

35

Mineral and chemical composition and some trace element contents in coals and coal ashes from Huaibei coal field, China  

Energy Technology Data Exchange (ETDEWEB)

The mineral and chemical compositions and some trace element contents (As, Ba, Cr, Mn, Mo, Sb, Th, U and V) in coal and coal ash samples from the Huaibei coal field in China were studied. This high volatility bituminous coal has low moisture and S contents, moderate ash yield and high calorific value. The coal ash is abundant in aluminosilicates as the contents of the Fe oxides are relatively similar to the sum of the alkaline earth oxides. The minerals identified in the coal are mainly quartz, kaolinite, pyrite and calcite and, to lesser extents, dolomite, ankerite, illite, chlorite, opal, feldspars, marcasite, gypsum, melanterite and hematite. Common minerals in the high temperature ash (815 C) are original quartz and newly formed anhydrite, lime, hematite and Ca-Mg silicates. Some trace elements such as Cr {gt} Th {gt} V {gt} Mo in the coal (in particular Cr and Th) and Cr {gt} Th {gt} V in the coal ash (in particular Cr) are enriched in comparison with the Clarke concentrations.

Liu, G.J.; Vassilev, S.V.; Gao, L.F.; Zheng, L.G.; Peng, Z.C. [University of Science & Technology China, Anhua (China). Dept. of Earth & Space Science

2005-08-01

36

Mineral and chemical composition and some trace element contents in coals and coal ashes from Huaibei coal field, China  

International Nuclear Information System (INIS)

[en] The mineral and chemical compositions and some trace element contents (As, Ba, Cr, Mn, Mo, Sb, Th, U and V) in coal and coal ash samples from the Huaibei coal field in China were studied. This high volatility bituminous coal has low moisture and S contents, moderate ash yield and high calorific value. The coal ash is abundant in aluminosilicates as the contents of the Fe oxides are relatively similar to the sum of the alkaline earth oxides. The minerals identified in the coal are mainly quartz, kaolinite, pyrite and calcite and, to lesser extents, dolomite, ankerite, illite, chlorite, opal, feldspars, marcasite, gypsum, melanterite and hematite. Common minerals in the high temperature ash (815 deg.. C) are original quartz and newly formed anhydrite, lime, hematite and Ca-Mg silicates. Some trace elements such as Cr > Th > V > Mo in the coal (in particular Cr and Th) and Cr > Th > V in the coal ash (in particular Cr) are enriched in comparison with the Clarke concentrations

2005-01-01

37

Use of coal ash in road sector  

Energy Technology Data Exchange (ETDEWEB)

Based on work done at the Central Road Research Institute, India, it is shown that coal ash can be used in a variety of ways in the road sector. Ash can be utilised in bulk as a fill/embankment material, and also on its own when stabilised with chemical additives. Bottom ash has a great potential for use as a subbase material. 3 refs., 1 tab.

Kumar, A.; Dhawan, P.K.; Murty, A.V.S.R. [Central Road Research Institute, New Delhi (India)

1996-12-31

38

COMPARISON OF LEACHABLE TRACE ELEMENT LEVELS IN COAL GASIFIER ASH WITH LEVELS IN POWER PLANT ASH  

Science.gov (United States)

The paper gives results of a comparison of the levels of 14 trace elements in leachates from three types of ash of a common origin coal. The 1-year study was conducted at the Kosovo plant in Obilic, Yugoslavia, comparing coal gasifier ash with fly ash and bottom ash from a coal-f...

39

Pressurised coal dust firing - accompanying work to the development of separators for fluid ash and alkaline compounds. Final report; Druckkohlenstaubfeuerung - Begleitarbeiten bei der Entwicklung der Abscheideorgane fuer fluessige Asche und Alkaliverbindungen. Schlussbericht  

Energy Technology Data Exchange (ETDEWEB)

The basic idea of combined steam and gas turbine cycles with pressurised coal dust firing is to combust the coal dust under pressure and purify the arising flue gas without cooling and immediately relieve them at a gas turbine. While still hot the flue gas is then used to generate steam in a boiler and thus drive a further turbine, the so-called steam turbine. Before entering the gas turbine the flue gas must be freed of solids and gaseous pollutants so as to make it fit for the turbine. A particularly important part of the process is therefore the hot gas purification stage, where solid and liquid particles as well as certain gaseous pollutants such as alkaline compounds are separated from the flow. The present project comprised the following tasks: Theoretical study of gas and fluid flows in models of fluid ash separators for the purpose of ascertaining the transferability of the concepts to industrial-scale plants; study of the realisability at an industrial scale of the theoretically and experimentally examined separation methods; and the mathematical study of the equilibria between the alkaline substances and their respective getter materials, comparison with measurements obtained on pilot plants, and assessment of the transferability of the results to industrial-scale plants. (orig./SR) [Deutsch] Das Grundkonzept des kombinierten Dampf-/Gasturbinenprozesses mit Druck - Kohlenstaubfeuerung besteht darin, Kohlenstaub unter Druck zu verbrennen und die entstehenden Rauchgase ohne Abkuehlung zu reinigen und unmittelbar ueber eine Gasturbine zu entspannen. Mit dem dann noch heissen Rauchgas wird anschliessend in einem Kessel Dampf erzeugt und damit eine weitere Turbine, die Dampfturbine, betrieben. Das Rauchgas muss vor dem Eintritt in die Gasturbine von Feststoffen und gasfoermigen Schadstoffen soweit befreit werden, dass es turbinenvertraeglich ist. Ein besonderer Schwerpunkt bei dem Verfahren ist daher eine Heissgasreinigung sowohl hinsichtlich der Abscheidung von festen bzw. fluessigen Partikeln als auch von bestimmten gasfoermigen Schadstoffen, wie z.B. Alkaliverbindungen. Im Rahmen des Projekts wurden folgende Arbeiten durchgefuehrt: - Theoretische Untersuchungen der Gas- und Fluessigkeitsstroemung in den modelltechnisch untersuchten Fluessigascheabscheidern mit dem Ziel, die Uebertragbarkeit der Konzepte auf eine Industrieanlage zu verifizieren. - Mit Hilfe von Konstruktionsstudien sollte die Realisierbarkeit der theoretisch und experimentell untersuchten Abscheidemethoden im Industriemassstab ueberprueft werden. - Rechnerische Untersuchungen der Gleichgewichtsverhaeltnisse der Alkalien und den entsprechenden Gettermaterialien, Vergleich mit den Messungen in den Versuchsanlagen und Uebertragbarkeit der Ergebnisse auf die Anlagen in Industriemassstab. (orig./SR)

Vydra, K.

1996-05-01

40

Measurement of the ash content of coal  

International Nuclear Information System (INIS)

[en] A monitor for determining the ash content of coal in wagons consisting of a structure including means for irradiating each wagon as it passes the structure with a known dose of neutrons, means for detecting and measuring the intensities of ?-rays emitted by ash-forming elements in the coal, and means for providing as indication of the concentration of the ash-forming elements. There also are included interlocks for ensuring that the neutron source is only operated when a loaded wagon is in the appropiate position

1978-10-02

 
 
 
 
41

Agglomeration of coal ash in fluidized beds  

Energy Technology Data Exchange (ETDEWEB)

The defluidization behaviour of ash derived from Indian coal by combustion in a fluidized bed has been studied. Sintering temperatures for ash in several ranges of particle size were measured with a dilatometer. In agreement with the earlier work on other coals, it was found that, above the sintering temperature, pairs of complementary, limiting values of fluidization velocity and bed temperatures exist which mark the onset of defluidization when the ash particles are heated in a fluidized bed. A linear relation was observed between bed temperature and limiting defluidization velocity. The constants in the corresponding equations were calculated for two size ranges of particles.

Basu, P.; Sarka, A.

1982-08-01

42

Agglomeration of coal ash in fluidized beds  

Energy Technology Data Exchange (ETDEWEB)

The defluidization behaviour of ash derived from Indian coal by combustion in a fluidized bed has been studied. Sintering temperatures for ash in several ranges of particle size were measured with a dilatometer. In agreement with the earlier work on other coals it was found that above the sintering temperature pairs of complementary, limiting values of fluidization velocity and bed temperatures exist which mark the onset of defluidization when the ash particles are heated in a fluidized bed. A linear relation was observed between bed temperature and limiting defluidization velocity. The constants in the corresponding equations were calculated for two size ranges of particles.

Basu, P.; Sarka, A.

1983-08-01

43

Mutagenicity and genotoxicity of coal fly ash water leachate  

Energy Technology Data Exchange (ETDEWEB)

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals - sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significantconcentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mu m), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.

Chakraborty, R.; Mukherjee, A. [University of Calcutta, Calcutta (India). Dept. of Botany

2009-03-15

44

Coal ash behavior in reducing environments  

Energy Technology Data Exchange (ETDEWEB)

A key factor in the successful design and operation of coal gasification systems is the ability to control and mitigate ash-related problems. Some of the major ash-related problems are slag flow control, slag attack on the refractory, ash deposition on heat-transfer surfaces, corrosion and erosion of equipment materials, and emissions control. Such problems are closely tied to the abundance and association of the inorganic components in coal and the gasification conditions. The CABRE project is a three-year program designed to investigate the transformations and properties of coal ash in reducing environment systems. The CABRE project is organized into a three-task structure which is the backbone of the project's strength. Task 1, Analytical Methods Development, has concentrated on the special needs of analyzing samples produced under a reducing atmosphere as opposed to the more often studied combustion systems. Task 2, Inorganic Partitioning and Ash Deposition, has focused on the production of gasification-type samples under closely controlled conditions for the study of inorganic partitioning that may lead to deposition. Task 3, Ash and Slag Physical Properties, has made large gains in the areas of sintering and strength development of coal ashes under reducing atmospheres for the evaluation of deposition problems.

Erickson, T.A.; Benson, S.A.; Steadman, E.N.; Brekke, D.W.; Folkedahl, B.C.; Tibbetts, J.E.; Nowok, J.

1992-01-01

45

Coal ash behavior in reducing environments  

Energy Technology Data Exchange (ETDEWEB)

A key factor in the successful design and operation of coal gasification systems is the ability to control and mitigate ash-related problems. Some of the major ash-related problems are slag flow control, slag attack on the refractory, ash deposition on heat-transfer surfaces, corrosion and erosion of equipment materials, and emissions control. Such problems are closely tied to the abundance and association of the inorganic components in coal and the gasification conditions. The CABRE project is a three-year program designed to investigate the transformations and properties of coal ash in reducing environment systems. The CABRE project is organized into a three-task structure which is the backbone of the project`s strength. Task 1, Analytical Methods Development, has concentrated on the special needs of analyzing samples produced under a reducing atmosphere as opposed to the more often studied combustion systems. Task 2, Inorganic Partitioning and Ash Deposition, has focused on the production of gasification-type samples under closely controlled conditions for the study of inorganic partitioning that may lead to deposition. Task 3, Ash and Slag Physical Properties, has made large gains in the areas of sintering and strength development of coal ashes under reducing atmospheres for the evaluation of deposition problems.

Erickson, T.A.; Benson, S.A.; Steadman, E.N.; Brekke, D.W.; Folkedahl, B.C.; Tibbetts, J.E.; Nowok, J.

1992-12-01

46

Coal ash parameters by neutron activation  

International Nuclear Information System (INIS)

The coal parameters, ash content and ash slagging index, may be strongly related to the chemical composition of mineral impurities in coal. Based on this assumption the authors have examined the feasibility of neutron activation techniques, both as a laboratory and a well logging method, by recording induced ?-rays in the two energy intervals with the help of a scintillation ?-ray spectrometer. Results from the Upper Silesiab Coal Basin have shown that the method can be used to evaluate the ash content and ash fusion temperature, both in the laboratory and in well logging; the corresponding mean standard deviations being 1.5 wt% and 35oC; and 3 wt% and 45oC respectively. (author)

1994-01-01

47

Coal ash parameters by neutron activation  

Science.gov (United States)

The coal parameters, ash content and ash slagging index, may be strongly related to the chemical composition of mineral impurities in coal. Based on this assumption the authors have examined the feasibility of neutron activation techniques, both as a laboratory and a well logging method, by recording induced ?-rays in the two energy intervals with the help of a scintillation ?-ray spectrometer. Results from the Upper Silesiab Coal Basin have shown that the method can be used to evaluate the ash content and ash fusion temperature, both in the laboratory and in well logging: the corresponding mean standard deviations being 1.5 wt% and 35°C; and 3 wt% and 45°C, respectively.

Chru?ciel, Edward; Chau, Nguyen Dinh; Niewodnicza?ski, Jerzy W.

1994-12-01

48

Acid mine drainage mitigation using bulk blended fly ash/coal refuse mixtures: Column study results  

International Nuclear Information System (INIS)

[en] Many Appalachian coal refuse materials contain significant amounts of pyritic-S and are likely to produce acid mine drainage (AMD). A column technique was designed and implemented to evaluate the effects of various AMD mitigation treatments including fly ash, topsoil, lime, and rock-P. Two types of fly ash were tested, one at four rates of application, the other at two rates. Conventional lime plus topsoil, lime without topsoil, topsoil only, topsoil with fly ash, rock-P, rock-P plus topsoil, and rock-P plus fly ash were also evaluated and compared with pure refuse controls. The drainage from the unamended columns rapidly dropped to pH 2 with very high levels of Fe and Mn. Alkaline fly ash dramatically reduced drainage Fe concentrations as well as Mn when compared with untreated refuse. The rock-P treatment also improved drainage but eventually lost its mitigation capability. Leachate B concentrations were initially high for some of the ash columns, but decreased over time, while the unamended refuse B levels increased with time. Combined treatments of phosphate/ash, ash/topsoil, and pure refuse with topsoil were intermediate between the alkaline ash/lime treatments and unamended refuse in drainage quality. With further analysis, fly ash may prove to be a viable alternative to conventional topsoiling/lime treatments to control AMD if adequate alkalinity is present in the ash/refuse mixture. If fly ash alkalinity is inadequate to balance potential acidity, accelerated leaching of ash bound metals may occur. Therefore, the uncontrolled disposal of fly ash within coal refuse disposal facilities should be discouraged unless acid/base balance concerns are met

1993-01-01

49

Production of lightweight aggregate from coal ash  

Energy Technology Data Exchange (ETDEWEB)

NGK Insulators Engineering Division has developed a process for the production of an inexpensive, lightweight aggregate from the coal ash discharged from pulverized coal fired thermal power stations. The basic process consists of: 1) coal ash homogenization (adjustment of the amount of uncombusted carbon), 2) pelletizing, 3) sintering. Product specifications are as follows: particle size: 5n15 mm diameter; specific gravity: 1.3-1.45; compressive fracture strength: 100-120 kg; production cost: 2120-2660 Yen/t. The lightweight aggregate obtained can be used in concretes for thermal insulation, heat maintenance, sound absorption, sound insulation, water retention and filtration structures.

Kurashima, Y.; Umashima, T.

1983-01-01

50

The synsedimentary alkalinity-volcanic ash derived tonsteins of early Longtan age in South-Western China  

Energy Technology Data Exchange (ETDEWEB)

The stratigraphic and geographic distribution of early tonsteins in later Permian of south-western China has been systematically studied in this report. By means of contrast and research the eight seams' tonsteins characteristics of the petrography, mineralogy and geochemistry, it can be confirmed that all the tonsteins are alkaline-volcanic ash derived tonsteins from a different age. This finding has filled the record gap of alkaline-volcanic ash sediment in the coal formations of the world. Besides, it has important application value and theoretical significance. 8 refs., 4 figs., 1 tab.

Zhou, Y. [Kunming Institute of Coal Science, Kunming (China)

1999-07-01

51

Coal blending to reduce the ash fusion temperature of high fusability Huainan coal  

Energy Technology Data Exchange (ETDEWEB)

The ash fusion temperature of high ash fusability Huainan cleaning coal blended with four low ash fusability coals were studied. The results indicate that the ash fusion point of Huainan coal can be reduced effectively by coal blending. A low ash fusion coal can provide the flux for high ash fusion coal, which can reduce or eliminate the need to add a flux. The changes of ash fusion point for two blended coals are non-additivity. The ash fusion points are influenced largely by the coal ash components. In order to increase the proportion of high fusion Huainan coal in TEXACO coal water mixture (CWM) gasifer, the addition of flux is needed. The effects of coal blending on the features of CWM are also non-additivity. The concentration of CWM can be increased effectively, generally 3% to 5%, by coal blending for coals which present difficulty in slurry preparation. 5 refs., 3 figs., 5 tabs.

Li, H.; Chen, F. [Anhui University of Science and Technology, Huainan (China). Dept of Chemical Engineering

2002-10-01

52

Chlorination of coal ash at Ekibastuz coal field  

Energy Technology Data Exchange (ETDEWEB)

The Ekibastuz coal ash is an evironmentally danagerous mineral waste. Ash utilization is an urgent problem. One of its utilizations is chlorination aimed at obtaining aluminum, silicon, or their alloys. The chlorination residue is of practical interest to the construction industry. Experimental set-ups and methods are described. Based on the experiments, the composition of charges for ash chlorination of the presence of solid reducer was determined. At 1000/sup 0/C, with a charge composed of 85% ash and 15% metallurgical coke, the degree of chlorination of aluminum and silicon oxides was 78.5% and 41% respectively. The Ekisbatuz coal can be used as a reducer for ash chlorination. With a charge composed of 2/3 ash and 1/3 coal, the degree of chlorination of aluminum and silicon oxides was 78.5% and 51% respectively. Aluminum oxide is better to chlorinate from briquetted ashes. Physical and chemical analyses of the chlorination residue indicates the presence of alpha-quartz. Carbon is completely absent in the residue, which is a pure siliceous rock. Experiments with chlorination of pelletized ashes in the presence of solid reducer, particularly Ekibastuz coal, indicate the possibility of obtaining the following valuable components: aluminum and silicon chlorides (which can be reduced to metal or alloys), and pure siliceous stock as furnace residue. Fields of application for these products are chemistry, metallurgy, and the construction and cement industries.

Bikashev, G.K.

1981-01-01

53

Pilot study of coal ash compost  

Energy Technology Data Exchange (ETDEWEB)

Washington State University has begun plans to compost waste manure from the campus dairy farm, waste from the dining hall and waste paper. A study was undertaken to see if fly ash from the university power plant could be added to the compost. Five piles of coal fly and bottom ash (5 to 31% by weight) and manure were composted over a 10 week period and then cured for 3 weeks. A greenhouse bioassay was then conducted using samples of the 8.7% and 31.8% ash-compost. The compost was mixed into potting soil at rates of 0%, 25%, 50% or 100% by volume. Tomato plants were grown and weighed. The potting soil control had the best growth followed by the 25% and 50% ash-composts. The 100% ash-compost had the poorest growth. A field test of the remaining compost planted to barley showed that yields increased with increasing ash content (no replicates so statistical tests were not possible). Increase may be due to the extra micronutrients supplied by the ash. The authors conclude that the addition of coal ash to the compost would not inhibit biological activity and that the final product appears to be enhanced for use in field applications. Further work is required to determine the cause of the poorer performance in the potting soil mixes.

Beaver, T.

1994-12-31

54

Coal ash management in thermal power plants: a case study  

Energy Technology Data Exchange (ETDEWEB)

The various activities involved in the management of fly ash and bottom ash produced in coal-fired power plants are described. Some detail is given of ash management at the Chandrapura thermal power plant of Damodar Valley Corporation which has three ash handling systems designed on the basis of a series of slurry pumps. There are two ash ponds. Financial constraints are discouraging utilisation of coal ash for building materials. 4 refs., 1 tab.

Kumar, S. [Damodar Valley Corporation (DVC), Chandrapura (India)

1999-12-01

55

Development of high-performance coal gasification technology by high ash fusion point coals by coal blending method: behavior of coal ash fusion temperature and gasification characteristics  

Energy Technology Data Exchange (ETDEWEB)

Coals with higher ash fusion temperature tend to have lower gasification performances owing to the operation with higher air ratio, which is necessary to keep high temperature in the entrained flow coal gasifier. Since coal blending method decreases ash fusion temperature, it is possible to gasify high ash fusion point coals at high efficiency. This report presents the behaviour of ash fusion temperature by blending coal and test results of blending coal gasification in a 2T/D bench scale air-blown pressurized entrained flow coal gasifier. As a result, it was confirmed that it was possible to decrease the ash fusion point of a high ash fusion point coal from 1750{degree}C to 1400{degree}C by blending a low ash fusion point coal, and to improve the gasification performances by reducing the amount of air into the gasifier. And the operation performances such as slagging characteristics and handling of coal and char were improved.

Inumaru, J.; Hara, S.; Ashizawa, M.; Hamamatsu, T.; Takegawa, T.; Koyama, T. (CRIEPI, Yokosuka-shi (Japan). Yokosuka Research Lab.)

1991-10-01

56

West Virginia Coal: Guide to Ash-Fusion Characteristics.  

Science.gov (United States)

Ash-fusion temperatures for coal affect how efficiently and dependably electricity is generated. The 'wrong' ash fusion could seriously impact the coal-fired utility. The report includes information about the coal-fired utility, the importance of ash-fusi...

1986-01-01

57

Sensing the ash content of coal  

International Nuclear Information System (INIS)

The ash content of a coal sample is sensed by bombarding it with primary radiation comprising at least two spectrums of energies (46 KeV and 9-17 KeV ? and X-rays) to cause radiative reactions in the coal, sensing the secondary radiation generated by the radiative reactions caused by one of the two spectrums of energies (46 KeV), sensing the secondary radiations at a characteristic fluorescent energy of at least one element (e.g. iron) in the coal sample, the characteristic fluorescent energy being excited by the other of the two spectrums of energies (9-17 KeV), and using the sensed secondary radiations to determine the ash content of the coal. The ? and X-rays may come from a single lead 210 source or from separate sources. (author)

1981-01-01

58

Coal ash utilisation in Indonesia: an opportunity and challenge  

Energy Technology Data Exchange (ETDEWEB)

The installed capacity of coal-fired power plant was 1,600 MW in 1991 and is projected to be 18,566 MW in 2003/2004, where coal consumption of about 61.4 million tons will be required and 4.2 million tons of coal ash will be generated. Since environmental issues in Indonesia have recently become more stringent, the ash handling system, management and utilization of coal ash from power plants (being the largest producers) need to be resolved. At present most of the ashes (furnace bottom ash, pulverized fuel ash and cenosphere) generated by the steam power plants in Indonesia are transported to ash valley for placement and long term storage, and only a small amount of the coal ash is used for cement, aggregate blocks and other civil constructions. As the quality of Indonesian coal varies from one coal mine to another, the coal ash generated will also vary in its composition and characteristics. The need to standardize the quality of coal ash for cement industries is therefore required. In this paper the potential of coal ash, the opportunity for effective use of coal in several areas and the challenge of ash utilization in Indonesia are discussed. 4 refs., 5 tabs.

Panaka, P.

1996-08-01

59

Beneficiation of four metallurgical coals to three specified ash levels  

Energy Technology Data Exchange (ETDEWEB)

Classical washability curves, froth flotation tests, and other data relating to pilot-scale washing of four coals are provided. The four coals tested included: Denison coal, B.P. coal, Fording coal and Cardinal River coal. The results include ash contents and yields for each of the coals.

1980-01-01

60

Coal ash behavior in reducing environments  

Energy Technology Data Exchange (ETDEWEB)

This project is a four-year program designed to investigate the transformations and properties of coal ash in reducing environment systems. This project is currently midway through its third year. The work to date has emphasized four areas of research: (1) the development of quantitative techniques to analyze reduced species, (2) the production of gasification-type samples under closely controlled conditions, (3) the systematic gasification of specific coals to produce information about their partitioning during gasification, and (4) the study of the physical properties of ashes and slags under reducing atmospheres. The project is organized into three tasks which provide a strong foundation for the project. Task 1, Analytical Methods Development, has concentrated on the special needs of analyzing samples produced under a reducing atmosphere as opposed to the more often studied combustion systems. Task 2, Inorganic Partitioning and Ash Deposition, has focused on the production of gasification-type samples under closely controlled conditions for the study of inorganic partitioning that may lead to deposition. Task 3, Ash and Slag Physical Properties, has made large gains in the areas of sintering and strength development of coal ashes under reducing atmospheres for the evaluation of deposition problems. Results are presented for all three tasks.

Benson, S.A.; Erickson, T.A.; Brekke, D.W.; Folkedahl, B.C.; Tibbetts, J.E.; Nowok, J.W.

1994-10-01

 
 
 
 
61

Development of the ash-free coal (Hyper-coal) process: characteristics of the remaining ash  

Energy Technology Data Exchange (ETDEWEB)

Hyper-coal is an ash free (< 200 PPM) and alkali reduced (Na+K<0.5 PPM) coal, which can be directly fired in the high efficiency gas turbine generation system (1350{sup o}C type). A 0.1t/d bench-scale unit is now under construction in the Takasago Works of KOBE Steel Ltd., Hyogo, Japan, and the operation will be started on December 2003. The Hyper-coal sample was produced in a semi-continuous apparatus, which has 30 L of extraction vessel. Several hundred PPM of ash remained in the filtered HPC. This paper focuses the characteristics of such remaining ash. The metallic element component in Hyper-coal is largely different from the raw coal; Fe, Si and Ti occupy the majority in the remaining ash. The existence of organic metals such as siloxanes is confirmed, but the quantity is negligible. A TEM image indicates that the Hyper-coal ash is formed by nano-meter particles. XRD or XPS analysis cannot detect since the crystalline structure is too small. Rich domains of Si, Al, Ca and O appeared on the surface of a Hyper-coal in the SEM-EDX images. It is considered that most of the remaining ash may be the ultra fine particles which are too small to be filtered (pore size; 0.5 {mu}m), and dispersed in the solution. Aggregated metallic compounds may be formed when the solvent is removed by distillation by concentrating the solution. On the other hand, such a rich domain does not appear on Hyper-coal particle when a flasher removes the solvent. This suggests that the organic solids (Hyper-coal) and metallic compounds (ash) are formed separately in the flasher. 4 refs., 8 figs., 4 tabs.

Noriyuki Okuyama; Nobuyuki Komatsu; Takuo Shigehisa; Takao Kaneko [Kobe Steel, Ltd. (Japan)

2003-07-01

62

The fusion characteristics and mineral species of blended coal ash  

Energy Technology Data Exchange (ETDEWEB)

The fusion characteristic temperatures are measured for blended ashes which are a mix of 3 kinds of coal ash at different ratios. XRD is used to study the mineral behavior during heating. The results show that the blended ash fusion characteristic temperatures are not linear with mix ratio. Mineral composition in blended ash at high temperature is consistent with that in the ternary system phase diagram. The main reason why blended ash fusion temperatures are lower than that of a single coal ash is the formation of a low temperature eutectic between the minerals. With blended-coal being more and more utilized for coal combustion and gasification, the slag-bonding caused by their inorganics becomes a more serious problem, which directly influences the safe operation of boilers and gasification furnaces. The behavior of minerals in coal-ash has been widely studied for a single coal ash, and also analyzed with the ternary systems phase diagrams. However, it is rare to do so for blended-coal ash. In this paper, the authors select 3 kinds of single coal ash (Songmuping coal, Huangling coal, and Shenmu coal) to mix into 2 kinds of blended-coal ash, and measure blended-coal ash fusion characteristic temperatures and analyze the ash by XRD. The results are analyzed and discussed using the phase diagram of the ternary system SiO{sub 2}-Al{sub 2}O{sub 3}-CaO. In addition, the authors try to explain blended-coal-ash fusion characteristic from the viewpoint of micro-mineralogical. These results should be helpful for forecasting the blended-coal slag-bonding mechanism.

Li Fan; Zheng Ying; Qiu Jianrong; Zheng Chuguang [National Lab. of Coal Combustion, Wuhan (China)

1997-12-31

63

pH-dependent leaching of dump coal ash - retrospective environmental analysis  

Energy Technology Data Exchange (ETDEWEB)

Trace and major elements in coal ash particles from dump of 'Nikola Tesla A' power plant in Obrenovac near Belgrade (Serbia) can cause pollution, due to leaching by atmospheric and surface waters. In order to assess this leaching potential, dump ash samples were subjected to extraction with solutions of decreasing pH values (8.50, 7.00, 5.50, and 4.00), imitating the reactions of the alkaline ash particles with the possible alkaline, neutral, and acidic (e.g., acid rain) waters. The most recently deposited ash represents the greatest environmental threat, while 'aged' ash, because of permanent leaching on the dump, was shown to have already lost this pollution potential. On the basis of the determined leachability, it was possible to perform an estimation of the acidity of the regional rainfalls in the last decades.

Popovic, A.; Djordjevic, D. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

2009-07-01

64

Fusion of coal ash by thermomechanical analysis  

Energy Technology Data Exchange (ETDEWEB)

The shortcomings of current procedures for determining ash fusion temperatures are well known and documented. Many alternatives have been investigated in an attempt to overcome what is perhaps the major analytical problem faced by the coal industry in many countries. This paper describes how thermomechanical analysis (TMA) can be applied to the ash fusion problem and seeks to demonstrate the effectiveness of this modern instrumental method. A new method for determining ash fusion data based on high temperature TMA is described. The procedure produces a curve of volume contraction against temperature for a small disc of ash compacted under controlled conditions. Temperatures of maximum rate of shrinkage for the major fusion events can be determined from the differential curve. It is demonstrated that repeatability of the test is very good and that changes in sample size, heating rate, sample compression and holder geometry do not change major fusion temperatures by more than approximately 10 degrees C. The new procedure, based on modern instrumentation and Commonwealth Scientific and Industrial Research Organisation (CSIRO) innovation, overcomes the subjectivity, variability and general unsatisfactory nature of current tests for coal ash fusion in use worldwide. (author). 2 tabs., 8 figs., 4 refs.

Saxby, J.D.; Chatfield, S.P. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Coal and Energy Technology

1997-04-01

65

Mechanism of the neutralization of coal ash eluate by soil  

Energy Technology Data Exchange (ETDEWEB)

To assist the evaluation of the environmental effects of using coal ash from coal thermal power-generation for inland land reclamation, a study was made of the mechanism of the neutralization of coal ash eluate by acidic soils. It was discovered that this neutralization is based on the hydrolysis of substituent Al/sup 3 +/ which enters into ion exchange with the Ca/sup 2 +/ in the coal ash eluate. 10 references.

Sakada, M.; Seki, T.; Yokoyama, T.; Satoh, K.

1984-01-01

66

Mechanisms of ash fouling during low-rank coal combustion  

Energy Technology Data Exchange (ETDEWEB)

Four low-rank coals were investigated for fouling severity using bench and pilot combustion testing and microanalytical examination of fouling deposits. The coals contained varying levels of alkali and alkaline-earth elements that are commonly associated with initiating and accelerating ash fouling, including Na, Mg, K, Ca, and Fe. Combustion testing revealed that fouling deposits generated from these coals shared common chemical and physical properties. Four test coals from western US coal fields were selected, including the Beulah and Gascoyne lignites from western North Dakota and the Colstrip subbituminous coal from Montana, and the Utah Wasatch from Utah. Deposits were ranked from low-fouling to severe-fouling based on deposit build-up rate, deposit strength, and liquid-phase viscosity, which was calculated based on the chemistry and the gas temperature near the deposits at the time of quenching. Microanalysis of the deposits using scanning electron microscopy revealed that the gluing material or phase that was responsible for the cementing of the severe-fouling deposits that the gluing material or phase that was responsible for the cementing of the severe-fouling deposits was a low-melting-point sodium-calcium-rich silicate.

McCollor, D.P.; Zygarlicke, C.J.; Benson, S.A. [Univ. of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center

1996-12-31

67

An investigation of coal ash utilization  

Energy Technology Data Exchange (ETDEWEB)

Lists the characteristic values (specific gravity, pH, loss on ignition, flow value, flow gradient, Blaine value) of fly ashes from coal-fired power plants and classifies the uses of the different grades of fly ash. For each use, a corresponding flow chart is given. The following uses are considered: 1) soil substitute; 2) means of reducing the water content (in percent of dry weight) of high water content weak soil; 3) soil stabilization; 4) use as a void filler; 5) use as a filler for asphalt concrete. 7 figs., 3 tabs.

Arai, T.

1985-01-01

68

Slagging and fluidity behavior of coal ash under gasifier environment  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to predict the slagging and fluidity behavior of coal ashes from the physical/chemical properties of parent coals to determine the optimum operating parameter of a slagging-type coal gasifier. Three types of coal samples, such as Alaska Usibelli, China Datong and Posco (blended coal), are analyzed for their ash composition and ash fusion temperature. To investigate the effect of flux addition on ash slagging behavior, optimum quantity of CaO addition is evaluated with considering negative effect of CaO addition on gasification reaction. The effect of blending of Posco coal with Alaska and Datong coal on ash slagging is also investigated to expand the variety and performance of coal types in slagging-type entrained-bed gasifier. The results of the experiment shows that the optimum CaO fluxing quantity is 10%, 20% on Alaska and Dating coal, respectively. However, optimum blending ratio for ash slagging is not found when mixing Posco coal with Alaska or Datong coals. Melting and slagging characteristics of coal ash samples with changing temperature are examined in detail by DTA. ASTM ash melting temperatures as well as critical viscosity temperature are compared with TGA and DTA profiles. DTA experiments illustrate that coal ash starts to melt before the IDT (initial deformation temperature) and that theoretical T{sub CV} is well correlated with DTA profile. Experiment of ash fluidity are also carried on with the Alaska and Datong coal ashes using a high temperature viscometer. The experimental viscosity data is compared with the calculated viscosity and results show good correlation. As a result, viscosity of coal ash could be calculated with the Watt and Fereday equation in the high temperature range. The experimental results from this investigation will be used as reference data for determining optimum operating condition of 3t/d bench scale unit gasifier which is located in Ajou University, Suwon, Korea.

Kim, H.T.; Bae, H.J. [Ajou Univ., Suwon (Korea, Republic of). Energy Dept.; Lee, S.H.; Park, J.S. [Korea Inst. of Energy Research, Daejon (Korea, Republic of); Yun, Y.S.; Chung, S.W. [Inst. of Advanced Engineering, Suwon (Korea, Republic of). Electric Power Systems Lab.

1997-12-31

69

Serial batch leaching procedure for characterization of coal fly ash.  

UK PubMed Central (United Kingdom)

Although many leaching methods have been used for various purposes by research groups, industries, and regulators, there is still a need for a simple but comprehensive approach to leaching coal utilization by-products and other granular materials in order to estimate potential release of heavy metals when these materials are exposed to natural fluids. A serial batch characterization method has been developed at the National Energy Technology Laboratory that can be completed in 2-3 days to serve as a screening tool. The procedure provides an estimate of cumulative metals release under varying pH conditions, and leaching the sample at increasing liquid/solid ratios can indicate the rate at which this process will occur. This method was applied to eight fly ashes, adapted to the acidic or alkaline nature of the ash. The leachates were analyzed for 30 elements. The test was run in quadruplicate, and the relative standard deviation (RSD) was used as a measure of method reproducibility. RSD values are between 0.02 and 0.70, with the majority of the RSD values less than 0.3. The serial batch leaching procedure was developed as a simple, relatively quick, yet comprehensive method of estimating the risk of heavy metal release from fly ash when it is exposed to natural fluids, such as acid rain or groundwater. Tests on a random selection of coal fly ashes have shown it to be a reasonably precise method for estimating the availability and long-term release of cations from fly ash.

Hesbach PA; Kim AG; Abel AS; Lamey SC

2010-09-01

70

Norm in coal, fly ash and cement  

International Nuclear Information System (INIS)

Coal is technologically important materials being used for power generation and its cinder (fly ash) is used in manufacturing of bricks, sheets, cement, land filling etc. 222Rn (radon) and its daughters are the most important radioactive and potentially hazardous elements, which are released in the environment from the naturally occurring radioactive material (NORM) present in coal, fly ash and cement. Thus it is very important to carry out radioactivity measurements in coal, fly ash and cement from the health and hygiene point of view. Samples of coal and fly ash from different thermal power stations in northern India and various fly ash using establishments and commercially available cement samples (O.P.C. and P.P.C.) were collected and analyzed for radon concentration and exhalation rates. For the measurements, alpha sensitive LR-115 type II plastic track detectors were used. The radon concentration varied from 147 Bq/m3 to 443 Bq/m3, the radium concentration varied from 1.5 to 4.5 Bq/kg and radon exhalation rate varied from 11.8 mBq.kg-1.h-1 to 35.7 mBq.kg-1.h-1 for mass exhalation rate and from 104.5 mBq.m-2.h-1 to 314.8 mBq.m-2.h-1 for surface exhalation rate in coal samples. The radon concentration varied from 214 Bq/m3 to 590 Bq/m3, the radium concentration varied from 1.0 to 2.7 Bq/kg and radon exhalation rate varied from 7.8 mBq.kg-1.h-1 to 21.6 mBq.kg-1.h-1 for mass exhalation rate and from 138 mBq m-2h-1 to 380.6 mBq.m-2.h-1 for surface exhalation rate in fly ash samples. The radon concentration varied from 157.62 Bq/m3 to 1810.48 Bq/m3, the radium concentration varied from 0.76 Bq/kg to 8.73 Bq/kg and radon exhalation rate varied from 6.07 mBq.kg-1.hr-1 to 69.81 mBq.kg-1.hr-1 for mass exhalation rate and from 107.10 mBq.m-2.hr-1 to 1230.21 mBq.m-2.hr-1 for surface exhalation rate in different cement samples. The values were found higher in P.P.C. samples than in O.P.C. samples. (authors)

2006-01-01

71

Recent advances in recycling clean-coal ash  

Energy Technology Data Exchange (ETDEWEB)

Clean coal ashes obtained from coal-fired power stations equipped with FBC boilers and control technologies for SOx and NOx are currently under-utilized. This paper presents the laboratory results of a project to develop mixtures of controlled low strength material (CLSM) using such ashes. The laboratory study made use of ash from the North and South Silos at the Manitowoc Public Utilities power station. The primary goal of this study was to find high-volume applications for cement-based products using waste ashes from the combustion of high-sulfur coals. The two phases of the project were described. Fifteen coal ash samples from 8 different sources were characterized for their physical, chemical, mineralogical and microstructural properties. The study showed that structural-grade concrete could be manufactured using large amounts of conventional or clean-coal ash, blended ashes, high-sulfur coal ashes, or coal ash blends. The paper outlined the use of clean-coal ash as a setting time regulator in Portland cement; high performance materials using Illinois coal combustion by-products (CCP); clean-coal ash as a potential source for defined-performance concrete; use of superplasticizers in the production of high-volume fly ash (HVFA) concrete containing clean-coal ash and class F fly ash; the development of high-carbon CCPs and flue gas desulphurization by-products for roadway base construction; and, the use of flue gas desulphurization material and class F CCP in ready-mixed concrete. 177 refs.

Naik, T.R. [Wisconsin Univ., Milwaukee, WI (United States). Dept. of Civil Engineering and Mechanics

2004-07-01

72

Application of coal ash to road earthwork material  

Energy Technology Data Exchange (ETDEWEB)

Japan's coal consumption amount was over 100 million tons in 1988, and accompanied with that coal ash is increased. Effective utilization rate of coal ash is about 40%, and under the present social circumstances it is difficult to secure the place to dispose of ash on a large scale. Electric Power Development Co. has, therefore, decided to study the applicability of coal ash to the road earthwork material with the cooperation of the Public Works Research Institute of the Ministry of Construction and the Public Works Research Center Foundation. The study is made on the oversea coal ash, and aims at applying it to the road bodies which are used in large quantity among road members. Simple substance of coal ash banking tests, the mixture of coal ash and soft and weak earth banking tests, and banking tests of light weight banking materials were conducted. As a result, it was confirmed that the simple substance of coal ash can be used as the earth improving material, and the development of bubble ash as a light-weight banking material succeeded. In the future it is hoped that coal ash will be evaluated as a new material, and that the image of industrial waste will be sweeped off. 4 refs., 21 figs., 6 tabs.

Hirayama, Shuichi; Sato, Yasuaki; Naemura, Shozo (Electric Power Development Co., Ltd., Tokyo, Japan; Ministry of Construction, Tokyo (Japan))

1989-05-30

73

The utilisation of coal ash in hazardous waste management  

Energy Technology Data Exchange (ETDEWEB)

The existing use of coal ash in South Africa for the management of hazardous waste is described. These include the use of fly ash extended cement in the manufacture of concrete encapsulation cells, the use of coarse ash in road making, the use of coal ash as a cover material, the mitigation of hazards associated with flammable wastes and the use of coal ash in the co-disposal of hazardous liquid wastes. The potential utilisation of coal ash in other aspects of hazardous waste management is also described, including: lining of disposal sites, capping and sealing of waste, microencapsulation, remedial measures, mopping up spills, incineration, scrubbing in fluidised beds, zeolites and general drainage purposes. Some factors which have limited the utilisation of coal ash in hazardous waste management have also been listed. 13 refs.

Boswell, J.E.S. [Waste-Tech, Bedfordview (South Africa)

1994-12-31

74

Fly ash formation behavior in pulverized coal combustion  

Energy Technology Data Exchange (ETDEWEB)

The investigation of ash formation behavior is essential to better understand the slagging and fouling phenomena in pulverized coal combustion. In particular, the distribution of fly ash size and chemical composition play a dominant role for the ash deposition properties at boiler wall. The objective of this study is to clarify the ash formation mechanism and to predict fly ash size and chemical composition changes during coal combustion. The transformations of mineral matter during pulverized coal combustion were tracked by CCSEM (Computer Controlled Scanning Electron Microscopy) analysis for several char samples collected in the course of combustion. It is indicated that the included minerals in coal mainly coalesced to form larger fly ash particles, while the fragmentation took place in the liberated minerals. The new method to predict the distribution of fly ash size and chemical composition at some combustion degree was developed using CCSEM data of feed coal. Calculated results gave good agreement with measurement data.

Yamashita, Toru; Teramae, Tsuyoshi; Tominaga, Hiroaki [Idemitsu Kosan Co., Ltd. (Japan)

1998-12-31

75

Soil engineering properties and earthworking problems of coal ash and red mud  

Energy Technology Data Exchange (ETDEWEB)

A study was undertaken of problems encountered in the use of thermal power station coal ash and red mud (an aluminium smelting residue) as a banking or filling material, the aim being the effective utilization of these substances. Like clinker, coal ash and red mud can also be used as improvers, but there are various problems such as absorption swelling, strong alkalinity, and the difficulty of controlling the moisture content. Certain measures have to be carried out in on-site use to combat these problems. (11 refs.)

Ogino, H.; Noto, S.; Shimatani, N.; Kudo, S.

1982-01-01

76

The construction of concrete pavement incorporating coal ash  

Energy Technology Data Exchange (ETDEWEB)

In recent years, many Japanese thermal power plants have been converted from fuel oil to coal firing, with a resulting increase in the production of coal ash. Many ways of utilizing this ash are now applied on a practical basis. The authors report the use of coal ash as an admixture in concrete used for pavement at the site of Joban Joint Thermal Power's power plant. 2 figs., 3 tabs.

Origasa, M.; Itoh, H.

1985-01-01

77

The leaching characteristics of selenium from coal fly ashes  

Energy Technology Data Exchange (ETDEWEB)

The leaching characteristics of selenium from several bituminous and subbituminous coal fly ashes under different pH conditions were investigated using batch methods. Results indicated that pH had a significant effect on selenium leaching from bituminous coal ash. The minimum selenium leaching occurred in the pH range between 3 and 4, while the maximum selenium leaching occurred at pH 12. The release of selenium from subbituminous coal ashes was very low for the entire experimental pH range, possibly due to the high content of calcium which can form hydration or precipitation products as a sink for selenium. The adsorption results for different selenium species indicated that Se(VI) was hardly adsorbable on either bituminous coal ashes or subbitumminous coal ashes at any pH. However, Se(I) was highly adsorbed by bituminous coal ashes under acidic pH conditions and was mostly removed by subbitumminous coal ashes across the entire pH range. This result suggests that the majority of selenium released from the tested fly ashes was Se(IV). A speciation-based model was developed to simulate the adsorption of Se(IV) on bituminous coal fly ash, and the pH-independent adsorption constants of HSeO{sup 3-} and SeO{sub 3}{sup 2-} were determined. The modeling approach is useful for understanding and predicting the release process of selenium from fly ash.

Wang, T.; Wang, J.; Burken, J.G.; Ban, H.; Ladwig, K. [University of Missouri, Rolla, MO (USA). Dept. of Civil Architectural & amp; Environmental Engineering

2007-11-15

78

Technique to measure the temperature of agglomeration of coal ash  

Energy Technology Data Exchange (ETDEWEB)

Examination of deposits from gasification pilot units indicates that agglomerates of fused ash appear to form at temperatures below the initial deformation temperature as defined by the ASTM ash fusion test. A simple method was developed to estimate the temperature at which coal ash will begin to fuse or agglomerate in process equipment. This test confirms that fusion of ash occurs at temperatures below those of the ASTM ash fusion test. The test also offers a method to compare the fusion properties of ashes for several coals. (1 ref.)

Stallmann, J.J.; Neavel, R.C.

1980-08-01

79

Applicability of coal ash as a banking material  

Energy Technology Data Exchange (ETDEWEB)

The authors report laboratory experiments in which coal ash was used to improve high moisture content cohesive soil, and the resulting mixture tested for its suitability as a banking material. The coal ash used had been previously exposed to air and rain. The results of compaction, uniaxial compression and immersion CBR (California bearing ratio) tests indicated that the unconfined compression strength of a mixture of 30% coal ash in cohesive soil was 1.2 to 1.6 times as great as the strength of the soil when simply compacted. It is concluded that the pozzolanic reaction of coal ash can be utilized to achieve higher soil strength. 1 references.

Kurihara, H.; Fukuzawa, E.; Hayazaki, T.

1984-01-01

80

Metal release and speciation changes during wet aging of coal fly ashes.  

UK PubMed Central (United Kingdom)

Introduction of coal fly ash into aquatic systems poses a potential environmental hazard because of its heavy metal content. Here we investigate the relationship between solid phase transformations, fluid composition, and metal release and speciation during prolonged wet aging of a class C and class F coal fly ash. The class C ash causes rapid alkalinization of water that is neutralized over time by CO(2) uptake from air and calcite precipitation. The resulting aqueous metal concentrations are below regulatory limits with the exception of Cr; solubility constraints suggest this is released as chromate. Limited As release is accompanied by no change in solid-phase speciation, but up to 35% of the Zn in the ash dissolves and reprecipitates in secondary phases. Similar processes inhibit Ba and Cu release. In contrast, the class F ash causes rapid acidification of water and initially releases substantial quantities of As, Se, Cr, Cu, Zn, and Ba. Arsenic concentrations decline during aging because of adsorption to the iron oxide-rich ash; this is aided by As(III) oxidation. Precipitation processes lower Ba and Cr concentrations during aging. Se, Cu, and Zn concentrations remain elevated during wet aging and solid-phase Zn speciation is not affected by ash-water reactions. Total metal contents were poor predictors of metal release, which is predominantly controlled by metal speciation and the effects of ash-water reactions on fluid pH. While contact with atmospheric gases has little effect on class F ash, carbonation of class C ash inhibits metal release and neutralizes the alkalinity produced by the ash.

Catalano JG; Huhmann BL; Luo Y; Mitnick EH; Slavney A; Giammar DE

2012-11-01

 
 
 
 
81

Metal release and speciation changes during wet aging of coal fly ashes.  

Science.gov (United States)

Introduction of coal fly ash into aquatic systems poses a potential environmental hazard because of its heavy metal content. Here we investigate the relationship between solid phase transformations, fluid composition, and metal release and speciation during prolonged wet aging of a class C and class F coal fly ash. The class C ash causes rapid alkalinization of water that is neutralized over time by CO(2) uptake from air and calcite precipitation. The resulting aqueous metal concentrations are below regulatory limits with the exception of Cr; solubility constraints suggest this is released as chromate. Limited As release is accompanied by no change in solid-phase speciation, but up to 35% of the Zn in the ash dissolves and reprecipitates in secondary phases. Similar processes inhibit Ba and Cu release. In contrast, the class F ash causes rapid acidification of water and initially releases substantial quantities of As, Se, Cr, Cu, Zn, and Ba. Arsenic concentrations decline during aging because of adsorption to the iron oxide-rich ash; this is aided by As(III) oxidation. Precipitation processes lower Ba and Cr concentrations during aging. Se, Cu, and Zn concentrations remain elevated during wet aging and solid-phase Zn speciation is not affected by ash-water reactions. Total metal contents were poor predictors of metal release, which is predominantly controlled by metal speciation and the effects of ash-water reactions on fluid pH. While contact with atmospheric gases has little effect on class F ash, carbonation of class C ash inhibits metal release and neutralizes the alkalinity produced by the ash. PMID:23035817

Catalano, Jeffrey G; Huhmann, Brittany L; Luo, Yun; Mitnick, Elizabeth H; Slavney, Adam; Giammar, Daniel E

2012-10-12

82

Ionizing collectors and their potential for floating high ash coals  

Energy Technology Data Exchange (ETDEWEB)

Flotation plant feed consisting of fine (-0.5 mm), high ash (35.1%) coal and flocculation feed containing very high ash (67.1%) were subjected to froth flotation tests with conventional and ionizing collectors. Methyl isobutyl carbinol (MIBC) and kerosene were used as conventional collectors, whereas Pamak4 (linoleic + oleic + Rosin oil) was selected as an ionizing collector in consideration of higher HLB (hydrophile-lipophile balance) value due to the oleic acid. The flotation results at the minimum reagent dosage levels for 35.1% ash coal revealed that Pamak4 was more effective than kerosene and MIBC combination, giving 20% higher yield of clean coal at the same ash level (i.e. 15%). At higher dosages Pamak4 continued this trend yield-wise, loosing the comparative benefit ash-wise due to the collector adsorption of clay coated coal particles. The flotation of 67.1% ash coal at the lowest collector dosage with Pamak4 gave 15.4% more yield of clean coal with 4% lower ash than that using kerogen and MIBC combination. It can be concluded from this study that both yield and ash content of clean coal account for the efficiency of flotation process and hence ionizing collectors such as Pamak4, due to their better activity than kerosene, have immense potential for floating fine high ash coals in future. 10 refs., 4 figs., 2 tabs.

Hussain, S.A.; Ozbayoglu, G. [University of Engineering and Technology, Lahore (Pakistan). Mining Engineering Dept.

1994-12-31

83

Mineral and chemical composition of Yanzhou coal and coal ash (China), with volatilisation behaviour to 1000{sup o}C  

Energy Technology Data Exchange (ETDEWEB)

The mineral and chemical composition of the Yanzhou coal and coal ash (China), and the volatilisation behaviour of 16 elements (Al, As, Ca, Cl, Cu, F, Fe, K, Mg, Na, P, Pb, S, Si, Ti, Zn) during gradual heating of this coal (350, 650, 815 and 1000{sup o}C) were studied. This high volatile bituminous coal has low moisture and S contents, moderate ash yield, and high calorific value. The coal ashes belong to SiO{sub 2}-Al2O{sub 3}-Fe2O{sub 3}-CaO system abundant in aluminosilicates, as the contents of Fe oxides are significantly higher than the sum of alkaline earth oxides. The minerals identified in coal (in decreasing order of abundance) are quartz, kaolinite, illite, pyrite + marcasite, calcite, and gypsum, and, to a lesser extent, montmorillonite, dolomite and pyrrhotite. The inorganic phases in coal ash (350-1000{sup o}C) are aluminosilicate glass, quartz, destructed clay minerals, mullite, hematite, magnetite, plagioclase, anhydrite and lime. The volatilisation behaviour of elements during coal combustion shows that the emission ratios of the elements volatilised normally increase gradually with increasing temperatures. The elements studied can be divided into four groups according to their volatilisation at the maximum temperature: high volatile Cl > F (86-90%); moderate volatile S > K > Pb > Cu > Zn (24-42%); slight volatile (Mg,As)> Ca > Si (15-17%); and non-volatile elements such as Al, Fe, Na, P and Ti. The reason for the volatilisation behaviour of the above elements is discussed based on their modes of occurrence in coal and coal ash.

Liu, G.J.; Qi, C.C.; Vassilev, S.V.; Chen, Y.W. [University of Science & Technology China, Anhua (China)

2007-12-15

84

Coal Ash Corrosion Resistant Materials Testing Program  

Energy Technology Data Exchange (ETDEWEB)

The "Coal Ash Corrosion Resistant Materials Testing Program" is being conducted by The Babcock & Wilcox Company (B&W), the U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) at Reliant Energy?s Niles plant in Niles, Ohio to provide full-scale, in-situ testing of recently developed boiler superheater materials. Fireside corrosion is a key issue for improving efficiency of new coal fired power plants and improving service life in existing plants. In November 1998, B&W began development of a system to permit testing of advanced tube materials at metal temperatures typical of advanced supercritical steam temperatures (1100°F and higher) in a boiler exhibiting coal ash corrosive conditions. Several materials producers including Oak Ridge National Laboratory (ORNL) contributed advanced materials to the project. In the spring of 1999 a system consisting of three identical sections, each containing multiple segments of twelve different materials, was installed. The sections are cooled by reheat steam, and are located just above the furnace entrance in Niles? Unit #1, a 110 MWe unit firing high sulfur Ohio coal. In November 2001 the first section was removed for thorough metallurgical evaluation after 33 months of operation. The second and third sections remain in service and the second is expected to be removed in the fall of 2003; the last is tentatively planned for the fall of 2004. This paper describes the program; its importance; the design, fabrication, installation and operation of the test system; materials utilized; experience to date; and results of the evaluation of the first section.

McDonald, D.K.

2003-04-22

85

Coal cleaning and the removal of ash from coal  

Energy Technology Data Exchange (ETDEWEB)

A method is described for treating a coal containing mass to reduce the ash components which comprises: (1) crushing the mass smaller than 20 mesh; (2) slurrying the crushed mass with water and an immiscible heavier-than-water organic media employing an intense mixing sufficient to cause intimate contact of the crushed mass with each liquid component of the slurry without an appreciable attrition; (3) carrying out a mild to substantially quiescent mixing sufficient to allow some initial disengagement of the water phase and its occluded ash from the organic media phase and its occluded coal; (4) separating the water phase from the heavier-than-water media phase including their respective solids in a raked settler; (5) collecting the separated phases and freeing the solids in each phase from its liquid; (6) drying the solids by contact with a heated surface.

Robbins, L.A.

1986-03-11

86

Study of the behaviour of leached components of coal ash  

Energy Technology Data Exchange (ETDEWEB)

Various kinds of coal ash were leached with hydrochloric acid. With the leaching solution at an initial pH of 2 or above, small amounts of Al, Si, Ca, Cr, Mo, and V were eluted. After the termination of leaching, the pH had become alkaline, rising to 9.5-13. Starting with a comparatively strongly acidic leaching solution of pH 1 or less, all twenty elements for which analytic facilities has been provided were eluted. As a result of re-precipitation due to hydrolysis, the elution behaviour of the main elements was very complex. In addition, their behaviour was greatly affected by the properties of the sample being tested. 10 references.

Kosuge, K.; Hamada, Y.; Tamagawa, T.

1984-01-01

87

The physical and chemical characteristics of pulverized coal combustion ashes  

Energy Technology Data Exchange (ETDEWEB)

Japan is the world's largest consumer of coal. Most of it is imported from various countries around the world. While coal generates more CO{sub 2}, which contributes to the greenhouse effect more than other types of fuel, plans are being drawn up to depend more on coal energy in order to maintain diversity in energy sources. Production of coal ash will increase as a result. In Japan, therefore, the public and private sectors are active in both developing and implementing clean, efficient and effective coal utilization technologies. More than 100 types of coal are being burned in Japan at present. For example, a power generating plant burns 20 to 40 different types of coal annually. Since a single type or coal blended with several different types are burned in Japan, the properties of coal ash differ by consuming plant and season. Therefore, understanding coal ash characteristics based on various properties is essential to the effective utilization of coal. The center of Coal Utilization, Japan has researched and developed effective utilization of coal ash as a supplementary project of the Ministry of International Trade and Industry. Chemical, physical, soil, and leaching characteristics, which are fundamental to using pulverized coal ash as a civil engineering material in large quantities, were selected and are described in this report.

Ozasa, Kazuo; Kamijo, Tsunao; Owada, Tetsuo; Hosoda, Nobumichi

1999-07-01

88

Ash transformation during co-firing coal and straw  

DEFF Research Database (Denmark)

Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal quality on fly ash and deposit properties, straw was co-fired with three kinds of coal in an entrained flow reactor. The compositions of the produced ashes were compared to the available literature data to find suitable scaling parameters that can be used to predict the composition of ash from straw and coal co-firing. Reasonable agreement in fly ash compositions regarding total K and fraction of water soluble K was obtained between co-firing in an entrained flow reactor and full-scale plants. Capture of potassium and subsequent release of HCl can be achieved by sulphation with SO2 and more importantly, by reaction with Al and Si in the fly ash. About 70-80% K in the fly ash appears as alumina silicates while the remainder K is mainly present as sulphate. Lignite/straw co-firing produces fly ash with relatively high Cl content. This is probably because of the high content of calcium and magnesium in lignite reacts with silica so it is not available for reaction with potassium chloride. Reduction of Cl and increase of S in the deposits compared to the fly ashes could be attributed to sulphation of the deposits.

Zheng, Yuanjing; Jensen, Peter Arendt

2007-01-01

89

Utilization of coal ash as a road material: a coal ash road that is strong in cold weather  

Energy Technology Data Exchange (ETDEWEB)

A study was made of the use of coarse ash as a road material. Coarse ash forms the greater part of the coal ash that is discharged as waste. Tests of ash that had been disposed of without further treatment and left (established ash) revealed excellent bearing power, workability and resistance to frost heave. This information provides a clue to the development of substitutes for gravel and sand. The author suggests that constructive use of the hydraulicity of ash may be made in general civil engineering as well as in road construction, where the ash is used for ground improvement and control of frost heave.

Igarashi, K.

1982-01-01

90

Sorption and chemical transformation of PAHs on coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Studies to be carried out in this project include: (1) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (2) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (3) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (4) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of surface roughness'' of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles; (5) Identification of the major products of chemical transformation of PAHs on coal ash particles, and examination of any effects that may exist of the nature of the coal ash surface on the identities of PAH transformation products; and (6) Studies of the influence of other sorbed species on the chemical behavior of PAHs and PAH derivatives on fly ash surfaces. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

Mamantov, G.; Wehry, E.L.

1991-01-01

91

Mullitization of black coal fly ashes  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper are presented the results of experiments focused on the study of thermal treatment influence of selected black coal flyashes from the heating plant in Kosice and the power plant in Vojany. The study was realized with original not pretreated samples.The obtained results confirmed that after the thermal treatment of both samples the phase’s change of material occurred. At 1050 °C,the decrease of amorphous phase was remarked, being transformed to the mullite and spinel. This information allow of the use examinedfly ashes samples as the matrix for the mullite composites preparation providing the stoichiometric change of thermally treated mixture.

Mária Kušnierová; Mária Praš?áková; Dalibor Matýsek; Vladimír ?ablík

2011-01-01

92

Geochemistry of coals, coal ashes and combustion wastes from coal-fired power stations  

Energy Technology Data Exchange (ETDEWEB)

Contents, concentration trends, and modes of occurrence of 67 elements in coals, coal ashes, and combustion wastes at eleven Bulgarian thermoelectric power stations (TPS) were studied. A number of trace elements in coal and coal ash have concentrations greater than their respective worldwide average contents (Clarke values). Trace elements are concentrated mainly in the heavy accessory minerals and organic matter in coal. In decreasing order of significance, the trace elements in coal may occur as: element-organic compounds; impurities in the mineral matter; major components in the mineral matter; major and impurity components in the inorganic amorphous matter; and elements in the fluid constituent. A number of trace elements in the waste products, similar to coal ashes, exceed known Clarke contents. Trace elements are mainly enriched in non-magnetic, heavy and fine-grained fractions of fly ash. They are commonly present as impurities in the glass phases, and are included in the crystalline components. Their accessory crystalline phases, element-organic compounds, liquid and gas forms, are of subordinate importance. Some elements from the chalcophile, lithophile and siderophile groups may release into the atmosphere during coal burning. For others, the combustion process appears to be a powerful factor causing their relative enrichment in the fly ash and rarely in the bottom ash and slag. 65 refs., 1 fig., 11 tabs.

Vassilev, S.V.; Vassileva, C.G. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Central Lab. of Mineralogy and Crystallography

1997-03-01

93

Geochemistry of coals, coal ashes and combustion wastes from coal-fired power stations  

International Nuclear Information System (INIS)

[en] Contents, concentration trends, and modes of occurrence of 67 elements in coals, coal ashes, and combustion wastes at eleven Bulgarian thermoelectric power stations (TPS) were studied. A number of trace elements in coal and coal ash have concentrations greater than their respective worldwide average contents (Clarke values). Trace elements are concentrated mainly in the heavy accessory minerals and organic matter in coal. In decreasing order of significance, the trace elements in coal may occur as: element-organic compounds; impurities in the mineral matter; major components in the mineral matter; major and impurity components in the inorganic amorphous matter; and elements in the fluid constituent. A number of trace elements in the waste products, similar to coal ashes, exceed known Clarke contents. Trace elements are mainly enriched in non-magnetic, heavy and fine-grained fractions of fly ash. They are commonly present as impurities in the glass phases, and are included in the crystalline components. Their accessory crystalline phases, element-organic compounds, liquid and gas forms, are of subordinate importance. Some elements from the chalcophile, lithophile and siderophile groups may release into the atmosphere during coal burning. For others, the combustion process appears to be a powerful factor causing their relative enrichment in the fly ash and rarely in the bottom ash and slag. 65 refs., 1 fig., 11 tabs

1997-01-01

94

Fine ash formation during pulverized coal combustion  

Energy Technology Data Exchange (ETDEWEB)

In this study, 15 pulverized coal samples were burnt in a drop-tube furnace to investigate the formation of fine particulates and the influence of coal ash properties on their emission. Coal combustion was carried out at 1673 K in air. Fine particles were collected by a cyclone and a low-pressure impactor. The elemental compositions of the collected particles were analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy. We examined the chemical compositions of the fine particles as a function of particle diameter and examined the proportions of the elements in the parent coal samples. We determined that almost all particles less than 0.22 {mu}m in diameter were formed by means of volatilization-condensation of SiO{sub 2} and Al{sub 2}O{sub 3} in the coal. We also demonstrated that the amount of SiO{sub 2} in particle size less than 0.22 {mu}m in diameter was related to the amount of fine included quartz and clay minerals in the parent coal. The primary components of particles greater than 0.76 {mu}m in diameter were SiO{sub 2} and Al{sub 2}O{sub 3}, and as the diameter of the particles decrease, the mass fractions of iron, magnesium, calcium, and phosphorus increased. However, the particle diameter at which this tendency commenced differed depending on the element. Particles between 0.22 and 0.76 {mu}m in diameter were thought to have been formed by the fragmentation and coalescence of particles in the coal and by the simultaneous condensation of volatilized elements onto other particles. 17 refs., 12 figs., 1 tab.

Tsuyoshi Teramae; Takayuki Takarada [Idemitsu Kosan Company, Limited, Chiba (Japan). Coal and Environmental Research Laboratory

2009-04-15

95

A study of the relationship between ash fusion temperatures and ash chemistry for an Australian coal  

Energy Technology Data Exchange (ETDEWEB)

The relationship between ash fusion temperatures and ash chemistry was investigated for 106 coal samples from the Thiess Dampier Mitsui Coal Pty. Ltd. mine at Moura in Central Queensland. The aim of the study was to investigate the cause of variability in ash fusion temperatures and develop a set of empirical equations whereby these temperatures could be predicted or checked from ash analyses. The method of regression analysis was employed to produce equations with standard errors of prediction comparable to laboratory reproducibility for all of the commonly reported ash fusion temperatures except Initial Deformation Temperature.

Quinn, G.; Farrelly, C.

1992-01-01

96

Multinuclear NMR approach to coal fly ash characterization  

Energy Technology Data Exchange (ETDEWEB)

This report describes the application of various nuclear magnetic resonance (NMR) techniques to study the hydration kinetics and mechanisms, the structural properties, and the adsorption characteristics of coal fly ash. Coal fly ash samples were obtained from the Dave Johnston and Laramie River electric power generating plants in Wyoming. Hydrogen NMR relaxation times were measured as a function of time to observe the kinetics of hydration for the two coal fly ashes at different temperatures and water-to-cement ration. The kinetic data for the hydrated coal fly ashes were compared to the hydration of portland cement. The mechanism used to describe the kinetic data for the hydration of portland cement was applied, with reservation, to describe the hydration of the coal fly ashes. The results showed that the coal fly ashes differ kinetically from that of portland cement and from each other. Consequently, both coal fly ashes were judged to be poorer cementitious materials than portland cement. Carbon-13 NMR CP/MAS spectra were obtained for the anhydrous coal fly ashes in an effort to determine the type of organic species that may be present, either adsorbed on the surface or entrained.

Netzel, D.A.

1991-09-01

97

Utilization of Coal Fly Ash as CO Gas Adsorbent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research focused on coal fly ash fabricated as CO adsorbent. Coal fly ash having grain size of 325 mesh was characterized by XRF, XRD and SEM-EDX. Physical activation was done at temperatures of 5000C, 5200C, 5400C, 5600C, 5800C and...

Dyah Sawitri; Ayu Lasryza

98

Hyper-coal process to produce the ash-free coal  

Energy Technology Data Exchange (ETDEWEB)

Research and process development to produce the ash-free coal (Hyper-coal, HPC) has been carrying out since 1999. A new cost-effective process (Hyper-coal process) by the application of the solvent de-ashing technology can be adopted for the Hyper-coal process. Coal extraction rate achieved almost 70 wt.%daf (based on dry and ash-free coal) from some kinds of coals using two-ring aromatics as the recycle solvent. A gravity settling effectively removed insoluble residue from the solution. A flash separator recovered the solvent completely and produced Hyper-coal as a spherical fine particle, which containing several hundred PPM of ash. It was estimated that the calorie base cost of Hyper-coal would be competitive to a general coal price including its ash disposal cost in Japan.

Okuyama, Noriyuki; Komatsu, Nobuyuki; Shigehisa, Takuo [Coal and Energy Project Department, Technical Development Group, KOBE Steel, Ltd., 2-3-1, Shinhama Arai-cho, Takasago, Hyogo 676-8670 (Japan); Kaneko, Takao [Science and Technology Research Center, Mitsubishi Chemical Corporation, 1000, Kamoshida-cho, Aoba, Yokohama 227-8502 (Japan); Tsuruya, Shigeru [Division of Molecular Science, The Graduate School of Science and Technology, Kobe University, Rokkodai, Nada, Kobe, 657-8501 (Japan)

2004-07-15

99

Norm in coal, fly ash and cement  

Energy Technology Data Exchange (ETDEWEB)

Coal is technologically important materials being used for power generation and its cinder (fly ash) is used in manufacturing of bricks, sheets, cement, land filling etc. {sup 222}Rn (radon) and its daughters are the most important radioactive and potentially hazardous elements, which are released in the environment from the naturally occurring radioactive material (NORM) present in coal, fly ash and cement. Thus it is very important to carry out radioactivity measurements in coal, fly ash and cement from the health and hygiene point of view. Samples of coal and fly ash from different thermal power stations in northern India and various fly ash using establishments and commercially available cement samples (O.P.C. and P.P.C.) were collected and analyzed for radon concentration and exhalation rates. For the measurements, alpha sensitive LR-115 type II plastic track detectors were used. The radon concentration varied from 147 Bq/m{sup 3} to 443 Bq/m{sup 3}, the radium concentration varied from 1.5 to 4.5 Bq/kg and radon exhalation rate varied from 11.8 mBq.kg{sup -1}.h{sup -1} to 35.7 mBq.kg{sup -1}.h{sup -1} for mass exhalation rate and from 104.5 mBq.m{sup -2}.h{sup -1} to 314.8 mBq.m{sup -2}.h{sup -1} for surface exhalation rate in coal samples. The radon concentration varied from 214 Bq/m{sup 3} to 590 Bq/m{sup 3}, the radium concentration varied from 1.0 to 2.7 Bq/kg and radon exhalation rate varied from 7.8 mBq.kg{sup -1}.h{sup -1} to 21.6 mBq.kg{sup -1}.h{sup -1} for mass exhalation rate and from 138 mBq m{sup -2}h{sup -1} to 380.6 mBq.m{sup -2}.h{sup -1} for surface exhalation rate in fly ash samples. The radon concentration varied from 157.62 Bq/m{sup 3} to 1810.48 Bq/m{sup 3}, the radium concentration varied from 0.76 Bq/kg to 8.73 Bq/kg and radon exhalation rate varied from 6.07 mBq.kg{sup -1}.hr{sup -1} to 69.81 mBq.kg{sup -1}.hr{sup -1} for mass exhalation rate and from 107.10 mBq.m{sup -2}.hr{sup -1} to 1230.21 mBq.m{sup -2}.hr{sup -1} for surface exhalation rate in different cement samples. The values were found higher in P.P.C. samples than in O.P.C. samples. (authors)

Kant, K. [K.L.Mehta Dayanand College for Women, Dept. of Physics, Faridabad (India); Upadhyay, S.B. [B.S.A. College, Dept. of Physics, Mathura - 281 001 (U.P.), Mathura (India); Sharma, G.S. [B.S.A. College, Mathura - 281 001 (U.P.), Dept. of Physics, Mathura (India)

2006-07-01

100

The determination of 210Pb in coal, coal ash, coal cinder and soil  

International Nuclear Information System (INIS)

A radiochemical method is described for the determination of 210Pb in coal, coal ash, coal cinder and soil. The procedure includes sample dry ashing, leaching with HCl (1+1), separation with anion-exchange resin, purification as PbS precipitate and 210Bi beta counting. This method provides a good separation of 210Pb from other natural and artificial beta emitters. The half-life of 210Bi determined from the sample sources is 5.50d, which is close to the published value (5.01d). The lower limits of detection are 7.6 x 10-4 Bq/g for 10 g coal sample and 1.5 x 10-3 Bq/g for each and every 5 g of coal ash, coal cinder and soil samples. The 210Pb contents in the analyzed coal, coal ash, coal cinder and soil samples are 0.0316 +- 0.0097, 0.0712 +- 0.0760, 0.0109 +- 0.0035 and 0.0355 +- 0.0173 Bq/g and the chemical yields are 95.1% +- 2.5%, 97.2% +- 2.0%, 93.5% +- 1.6% and 95.7% +- 1.5% respectively. The enrichment factors (Ef) of 210Pb in coal ash, defined as the ratio of the content of 210Pb in coal ash to that in coal, range from 1.60 to 11.8 the method gives precision results. Four samples can be analyzed within 12 h (not including the time for counting). The technique is suitable for sample analysis on the environmental impact assessment of the coal-fuel power plant.

1994-01-01

 
 
 
 
101

Studies on the coal ash with leaching method  

Energy Technology Data Exchange (ETDEWEB)

In order to establish safety treatment and effective reuse technology for coal ash, the fundamental characteristics of the coal ash are first revealed. Next, water leaching applies to fly ash discharged from a coal fired plant, then the behavior of leachate components is examined. Processing of water leachate solution is also studied by blowing air and carbon dioxide gas. In addition, the leaching with hydrochloric acid and sulfuric acid is also tested for checking the behavior of leachates while examining the treatment of acid leachate solution by the neutralization method. For effectively using coal ash, various treatments are tested, including modification to light aggregate or sodium silicate together with the reuse of magnetite obtained by the wet type magnetic separator. Good separation of magnetite, contained in coal ash, and possible applications are confirmed. About 30% of SiO/sub 2/ can be used as a raw material of sodium silicate. (98 figs, 31 tabs, 57 refs, 7 photos)

Hamada, Yoshihisa; Tamagawa, Takeo; Osaki, Kazuo; Kato, Shigeru; Rokukawa, Naganori; Kosuge, Katsunori; Ichijo, Michio; Murayama, Katsuo

1987-03-25

102

Influence of sewage sludge addition on coal ash fusion temperatures  

Energy Technology Data Exchange (ETDEWEB)

The ash fusion characteristics of three types of bituminous coal (A, B, and C), one type of sewage sludge (W), and the corresponding coal-sewage sludge blends (10 and 50 wt % of sludge) were studied. The ash fusibility temperatures of samples in oxidizing atmosphere were measured, and their chemical and mineralogical compositions were determined. The addition of sludge to coal in certain proportions produces blends whose ashes have lower fusibility temperatures than those of coal and sludge. This is related to the differences in chemical composition and modes of elemental combination in both types of materials. The main differences are associated to the elements P, Fe, and Ca. As the sludge is much richer in Ca than the coals, the compositions of the blend ashes pass through low-temperature eutectic regions of the ternary phase diagrams SiO{sub 2}-CaO-Al{sub 2}O{sub 3} and SiO{sub 2}-CaO-Fe{sub 2}O{sub 3}. As a result, for the sludge-coal blend ashes series (one for each coal), the relationships between ash fusibility temperatures and the percentage of sludge ash in blend ashes fit to second-order polynomial functions. The minima of these functions, as well as some sludge-coal blend ashes, are located in the above-mentioned low fusion regions. Differing from coal ashes, in the sludge and 50 wt % blend ashes, the minerals calcium ferrite, larnite, and chloroapatite were found. 17 refs., 6 figs., 6 tabs.

M. Belen Folgueras; R. Maria Diaz; Jorge Xiberta; M. Purificacion Garcia; J. Juan Pis [University of Oviedo, Oviedo (Spain). Department of Energy and Department of Materials Science

2005-12-01

103

An overview of coal fly ash filler applications  

Energy Technology Data Exchange (ETDEWEB)

The sources of coal fly ash and its physical and chemical properties are described. One of the major uses of fly ash is as a filler in ready-mix concrete which represents about 49 per cent of fly ash utilization. When used in asphaltic concrete fly ash replaces limestone/marble dust. Estimated market share in 1999 is about 15 per cent. Fly ash is also used in asphalt roofing shingles, in thermoplastics, in paints, and in metal matrix composites. In metal matrix composites the fly ash can replace SiC, graphite, and alumina. tabs., figs.

Colmar, J.

1998-12-31

104

Active utilization of coal ash for soil stabilization  

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the suitability of the coarse ash and bottom ash components of coal ash as soil stabilizers. Little active use has yet been made of such ashes. The study involved relating the strength characteristics of soil treated with slaked lime and coarse ash (or bottom ash powder) mixtures, to the internal structure (at microscopic level) of the treated soil. 5cm diameter x 10cm long specimens were sealed in polyethylene bags, left to harden, and then subjected to uniaxial compression strength tests. 2 references.

Kawamura, M.; Torii, K.; Hasaba, S.

1983-01-01

105

Geotechnical properties of coal-fired thermal power plant ash  

Energy Technology Data Exchange (ETDEWEB)

This paper highlights that fly ash generated by coal-fired power plants has beneficial geotechnical properties, which could be utilized as a filling material for its adequate disposal. In this paper a typical composition of fly ash and bottom ash generated in the US has been tabulated. ASTM has distinguished the Class F and C ashes based on the concentration of silica, alumina and iron oxide and also as per the percentage of CaO content. It has been observed that dry unit weight of fly ash increases as its specific gravity increases. The bottom ash has indicated greater value of friction angle than sand. 16 refs., 3 tabs.

Roy, S. [National Institute of Rock Mechanics, Kolar Gold Fields (India)

2005-07-01

106

Soil stabilisation using alkaline activation of fly ash for self-compacting rammed earth construction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-earth construction. Different liquid:solid ratios, alkali concentrations and Na2O : ash ratios were tested. Effect of calcium hidroxide, sodium chlori...

Cristelo, Nuno; Glendinning, Stephanie; Miranda, T.; Oliveira, Daniel V.; Silva, Rui André Martins da

107

Solvent de-ashing of coal liquefaction products  

Energy Technology Data Exchange (ETDEWEB)

The two-stage brown coal liquefaction (BCL) process developed by Nippon Brown Coal Liquefaction (NBCL) Co., Ltd., consists of 4 sections: dewatering (DW), primary hydrogenation (PH), de-ashing (DA) and secondary hydrogenation (SH). In order to avoid difficulties with SH, ash contained in the heavy products (Coal Liquid Bottom, CLB) should be removed in DA. The solvent de-ashing under high temperature and high pressure is adopted as de-ashing process in the BCL process because of its high efficiency. The mechanisms of solvent de-ashing and the effects of the conditions such as temperature and CLB concentration on the efficiency of de-ashing are discussed. 1 ref., 7 figs., 1 tab.

Suda, S.; Okuma, O.; Nagae, S.; Okuyama, N.; Matsumura, T. (Kobe Steel Ltd. (Japan). Chemical Technology Research Laboratory)

1989-10-01

108

Sorption and chemical transformation of PAHs on coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. During the past year the following specific aspects of this broad problem area have been investigated: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (b) The use of gas-solid chromatography to measure heats of sorption of PAHS, and PAH derivatives, on coal fly ashes and ash fractions. (c) Identification of the major photoproduct(s) of the photodecomposition of one PAH (benz[a]anthracene) sorbed on model adsorbents; (d) Estimation of fractal dimensions'' of coal fly ash particles by use of specific surface area measurements, with an ultimate objective of using these measurements to assess the importance of inner-filter effects'' on the photodecomposition of PAHs sorbed on fly ash particles. (e) The photochemical transformation of a representative nitro-PAH derivative (1-nitropyrene) sorbed on fly ash. (f) Development of techniques for studying the nonphotochemical reactions of hydroxyl radicals (and other atmospheric constituents) with PAHs sorbed on fly ash. Progress achieved, and problems encountered, in each of these major areas of emphasis is described below.

Mamantov, G.; Wehry, E.L.

1992-01-01

109

Analytical characterization of coal ash: ELSAM - Idemitsu Kosan cooperation project  

Energy Technology Data Exchange (ETDEWEB)

A 1-year collaborative project on comparison of advanced methods for characterizing coal ashes was initiated in 1996 between ELSAM I/S, Denmark and Idemitsu Kosan Co., Ltd., Japan. A worldwide suite of 9 coals, 3 coal blends and 3 fly ashes was defined for analyses including: bulk ash composition; Computer Controlled Scanning Electron Microscopy; standard ash fusion temperatures; Simultaneous Thermal Analysis; High Temperature Light Microscopy (HTLM) analysis; and X-ray Diffraction Analysis. In this study, measurements of coal ash characteristics related to sintering, melting and viscosity were compared. Sintering characteristics were analyzed as linear shrinkage rate of pressed pellets by HTLM. The different coal types showed very different sintering characteristics. A melting behavior as function of temperature was tested using the results of Simultaneous Thermal Analysis (STA) analyses. Melting behavior is considered to be important in evaluation of ash deposition on heat transfer surface. Viscosities of coal ashes have been analyzed and compared with different viscosity models. The Urbain model generally gave satisfactory estimates. This has importance for modeling of ash deposition on heat transfer surface and slag flow characteristics. This paper provides a description of the methods, a comparison and interpretation of the analyses. 13 refs., 2 figs., 2 tabs.

Teramae, T.; Larsen, O.H.; Laursen, K. [Idemitsu Kosan Co., Ltd. (Japan). Coal Research Laboratories

1998-12-01

110

Occurrence, abundance and origin of minerals in coals and coal ashes  

Energy Technology Data Exchange (ETDEWEB)

the mineralogy of coal and coal ash samples from a wide variety of deposits worldwide has been studied by X-ray diffractometry, light microscopy, SEM, TEM and DTA-TGA methods. The common major minerals identified in the crystalline matter of coals are quartz, kaolinite, illite, calcite, pyrite, plagioclase, K-feldspar and gypsum, and occasionally dolomite, ankerite, siderite, Fe oxyhydroxides and sulphates. A number of minor and especially accessory minerals are also present. The modes of occurrence and some genetic peculiarities of the minerals found are described and summarized. Minerals and phases of probable detrital origin include mainly silicates, volcanic glass, oxyhydroxides and phosphates. Authigenic minerals of syngenetic origin may be sulphides, clay minerals, carbonates and rarely sulphates and phosphates. Epigenetic minerals, formed by the infiltration of low-temperature hydrothermal solutions, may include sulphides, carbonates, sulphates, clay minerals, quartz, chlorides, and probably alkaline-earth hydroxides and zeolites. The alteration products of detrital and authigenic minerals may be Fe and Al oxyhydroxides, sulphates, kaolinite, illite, chlorite, muscovite, zeolites and calcite. The behaviour of these minerals and phases during low- and high-temperature ashing is also discussed. 46 refs., 4 figs., 4 tabs.

Vassilev, S.V.; Vassileva, C.G. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Central Lab. of Mineralogy and Crystallography

1996-08-01

111

A study of coal type selection for a coal fired power plant considering coal and fly ash properties  

Energy Technology Data Exchange (ETDEWEB)

In this paper, coal type selection for a coal fired boiler in a thermal power station is investigated. Available data of actually used coal types are too small compared with properties of coal type and fly ash. Classification of coal and fly ash properties is, hence, introduced and the coal and fly ash properties are consolidated into several categories through the factor analysis. Applicability of coal is evaluated by using the multiple regression analysis where the explanatory variables are the factor scores for respective categories. The proposed coal type selection method is applied to a boiler in a thermal power plant and its effectiveness is evaluated.

Goto, S.; Masuda, K.; Nakamura, M.; Sueyoshi, M.; Furue, T.; Uchida, Y.; Hatazaki, H. [Saga University, Saga (Japan)

2009-01-15

112

Natural revegetation of coal fly ash in a highly saline disposal lagoon in Hong Kong  

Energy Technology Data Exchange (ETDEWEB)

Question: What is the relationship of the naturally colonizing vegetation and substrate characteristics in fly ash lagoons? Location: West lagoon, Deep Bay, a 13-ha coastal lagoon in Hong Kong in subtropical Southeast Asia. Methods: Vegetation establishment was examined in a coal fly ash lagoon two years after its abandonment to investigate the distribution of vegetation in relationship to the chemical properties of the fly ash in the lagoon. A greenhouse experiment assessed the limits imposed on plant growth in fly ash. Results: The fly ash was saline, slightly alkaline and very poor in organic matter and nitrogen. Ash from bare and vegetated areas differed significantly in their salinity and extractable concentrations of inorganic nitrogen and various metals. Bare ash had a significantly higher conductivity and extractable sodium, aluminum, manganese, potassium. and lead. In total 11 plant species that belonged to seven families were found growing on the fly ash: all species except the shrub Tamarix chinensis were herbaceous. Using discriminant analysis, the most important factors in distinguishing bare and vegetated ashes were conductivity and sodium. Cluster analysis of bare samples gave two distinct groups, one from the periphery of the lagoon, which had lower sodium, conductivity, organic carbon, potassium and copper, and the other from a second group that contained ashes from the central region of the lagoon. Results of the greenhouse experiment showed that the inhibition of plant growth was significantly correlated with the presence of soluble toxic elements in ash. Conclusion: Toxicity and salinity seem to be the major limiting factors to plant establishment in fly ash, and these factors must be ameliorated for the successful reclamation of these fly ash lagoons.

Chu, L.M. [Chinese University of Hong Kong, Hong Kong (China). Dept. of Biology

2008-08-15

113

Coal de-ashing with the method of spherical agglomeration  

Energy Technology Data Exchange (ETDEWEB)

The paper presents results of an experimental study of de-ashing of coals using spherical agglomeration. The separation effect of the coal mineral matter and the agglomeration characteristic of coal were investigated using different added oils, and varying the mixing speed and other parameters. (12 refs.)

Byeong-wo-Choi; Seong-gyu Kang; Dong-chan Kim

1982-06-01

114

The study on coal gasification process with high ash fusion temperature coal  

Energy Technology Data Exchange (ETDEWEB)

Coal gasification experiment was conducted with high ash fusion temperature coal in an entrained flow gasifier to evaluate the dry-ash removal process. In the conventional entrained type coal gasification process, coal ash was removed as the molten slag at the bottom of gasifier. Therefore, comparatively low fusion ash temperature coal was usually used in these gasification processes. However, it is very important to use the high ash fusion temperature coal in the coal gasification process in the near future to achieve the high power generation efficiency. Form these reasons, new gasification process with high ash fusion temperature was proposed and gasification experiment was conducted. In the proposed process, the ash was removed without melting. Therefore, the gasification condition on each coal characteristics was very important. In this study, the gasification experiment with different operation condition, such as O{sub 2}/Coal, was conducted with two different types of coal. To evaluate the gasification performance and ash behavior, produced gas composition was measured and recovered ash after the gasification experiment was analyzed. 10 refs., 8 figs., 2 tabs.

Nobusuke Kobayashi; Miku Tanaka; Piao Gulin; Jun Kobayashi; Shigenobu Hatano; Yoshinori Itaya; Shigekatsu Mori [Nagoya University, Nagoya (Japan). Dept. of Chemical Engineering

2007-07-01

115

Ignition of ash-coal particles and aerosols  

Energy Technology Data Exchange (ETDEWEB)

The ignition of individual coal particles of different ash content (4.5-72%) has been investigated experimentally and theoretically as well as the ignition of aerosols of such particles. It has been determined that depending on the ash content in coal and the ignition-ash fusion temperatures relation, there are different mechanisms of ignition (thermal or thermal-kinetic), which are similar to the ignition of metal particles with porous or continuous oxide film. The comparison of the experimental and calculated values of the coal particles aerosol ignition temperature is given. 6 refs., 2 figs.

Klyachko, L.A.; Vovchuk, Y.I.; Kiro, S.A.; Zolotko, A.N. [Central Institute of Aviation Motors, Moscow (Russian Federation)

1995-12-31

116

Coal ash - a useful raw material for Portland cement manufacture  

Energy Technology Data Exchange (ETDEWEB)

One necessary ingredient in the manufacture of Portland cement is alumina (Al{sub 2}O{sub 3}). This oxide is normally sourced from naturally occurring materials such as clay, shale or bauxite. It can also be sourced from by-product materials such as anorthosite slimes and coal ash. The concept of mix solution region (MSR) is used to clarify cement raw mix design so that the usefulness of coal ash as a raw material is more easily understood. This paper highlights the important chemical changes in the cement clinker chemistry brought about by switching from shale to coal ash as the source of alumina. 2 refs., 3 figs., 4 tabs.

Kelly, R.J. [Blue Circle Cement (Pty) Ltd., Johannesburg (South Africa)

1994-12-31

117

Characterization and leaching of coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Physical characteristics, chemical composition and leaching behaviour of a waste fly ash from a coal-fired power station are reported. Particle size distribution was studied by the following techniques; sedimentation in a liquid medium; sedimentation in an air flow; and Fraunhofer diffraction of a laser beam. Results obtained by the different methods are in good agreement. Mineralogical content and chemical composition were determined by X-ray diffraction, electronic microprobe and X-ray fluorescence. Acid leaching of the samples was investigated, using the following strong acids in sequence: HCl+HNO[sub 3], H[sub 2]F[sub 2], HClO[sub 4]. Analysis of leachat by atomic absorption shows trace metals In, Tl, Ge, Cu, Ga, Pb, Ni, Co, Mn, Cd, Zn, Cr. In this work, fly ashes from a Spanish power plant are characterized according to the type of particles, size distribution and chemical composition by means of physical methods. Three particle size fractions are leached by acids and analysis of trace elements in the leaching liquor is carried out. The concentration of trace metals is somewhat higher in the particles of smallest size. 12 refs., 4 figs.

Gutierrez, B.; Pazos, C.; Coca, J. (University of Oviedo, Oviedo (Spain). Dept. of Chemical Engineering)

1993-08-01

118

Coal ash - innovative applications of coal combustion products (CCPs)  

Energy Technology Data Exchange (ETDEWEB)

The book provides a concise overview of Coal Combustion Products (CCP) production and use, as well as a sampling of the wide range of CCP applications that can be found throughout the USA and internationally. These selected CCP applications include: concrete products, geotechnical projects, manufactured products, agricultural and environmental uses and examples of CCP applications for highway and building construction. These are well illustrated with colour photographs. A technical section provides an overview of CCP production, physical and chemical characteristics of CCPs, and the wide variety of guidelines, standards and regulations that play a part in the selection of CCPs for a variety of uses. The benefits of membership of the American Coal Ash Association are also briefly reviewed.

Dienhart, G.J.; Stewart, B.R.; Tyson, S.S.

1998-07-01

119

Computer estimation of the ash content of coal strata  

International Nuclear Information System (INIS)

[en] The code ''Zolnost-1'' system has been developed for the determination of the coal ash content by means of gamma logging. The system is based on the statistical relation between the ash content and the measured intensity of the coal bed gamma radiation. The major ash component is represented by alumosilicates whose content is responsible for the enhanced ash content and the intensity of the coal gamma radiation respectively. The above statistical relation discontinues at the enhanced coal bed radioactivity. In this case the method is unsuitable. The technique for gamma logging data input into a computer is described. The operation results of the system are printed out in a digital form. The time spent by the system for data processing for one bed intersection is 15-30 s, and for data preparation 5-7 min

1976-01-01

120

A process for producing a hardened product of coal ash  

Energy Technology Data Exchange (ETDEWEB)

A process for producing a hardened board product of coal ash comprising the steps of treating the coal ash with sulfuric acid, mixing with water and a hydraulic material, and shaping and curing the mixture, characterized by the following steps: - adding sulfuric acid and/or hydrochloric acid to coal ash and allowing them to react with each other to obtain a first reaction mixture; - adding calcium carbonate to the first reaction mixture and allowing the first reaction mixture to react with the calcium carbonate to obtain a second reaction mixture; mixing the second reaction mixture with water and at least one hydraulic material selected from the group consisting of cement, slag, gypsum, slaked lime and quick lime to obtain a third reaction mixture; and shaping and curing the third reaction mixture to obtain the hardened board product of coal ash.

Matsuura, S.; Ando, S.; Kiso, M.

1988-06-29

 
 
 
 
121

Advanced characterisation of coal minerals, ash and slag: applications in coal utilization  

Energy Technology Data Exchange (ETDEWEB)

The nature of mineral matter in coal determines its transformation into ash during combustion and the nature of resulting ash, (eg chemical composition and particle size distribution), and subsequently influences the ash deposition behaviour. The conventional indices for ash deposition based on the chemical composition of ash and the Ash Fusion Temperatures did not prove to be adequate due to the heterogeneous nature of mineral matter. The paper discusses two new techniques required for estimating the performance: the Computer Controlled Scanning Electron Microscopy (CCSEM) and Thermo-Mechanical Analysis (TMA). The behaviour of mineral matter is primarily influenced by three parameters: the mineral type (quartz, siderite, calcite or pyrites), grain size, and whether the mineral grains are within the coal matrix or not. CCSEM of coal provides such information on mineral matter in coal. CCSEM data are, therefore, processed to predict the fouling and slagging characteristics of several coals. TMA describes thermal behaviour of ash deposits over complete range of temperature and gives much more information compared to what standard Ash Fusion Temperatures provide. The analysis from such a technique can be used to characterise the ash deposits in terms of their structure and thermal properties. The two techniques together with the thermodynamic calculations have capabilities of characterising coal in terms of their ash depositional behaviour and the resulting ash deposits in terms of their structure. 22 refs., 4 figs.

Wall, T.F.; Gupta, R.P.; Bryant, G.; Gupta, S.K.; Li Yan [University of Newcastle, Newcastle, NSW (Australia). Department of Chemical Engineering, CRC for Black Coal Utilisation

1998-12-01

122

Elution control of arsenic ion from sewage sludge-ash by coating with coal bottom-ash  

Energy Technology Data Exchange (ETDEWEB)

A unique control method was developed for toxic ion elution from sewage sludge-ash in an acid solution. Coated sewage sludge-ash pellets were prepared by covering with bottom ash from a coal-fired boiler. Since the melting temperature of inner sewage sludge-ash was lower than that of outer coal bottom-ash, coated sewage sludge-ash was heated rapidly in order to melt only the surface of a pellet. The heating conditions were determined based on the observed thermal conductivities of sewage sludge -ash and coal bottom-ash. Elution tests were carried out in hydrochloric acid and nitric acid solution for the sewage sludgeash pellets with and without coal bottom-ash coating. The coating of sewage sludge-ash completely suppressed the elution of arsenic ion in both solutions, whereas the uncoated pellets showed considerable elution.

Enda, Y.; Sugawara, K.; Sugawara, T. [Industrial Technology Center for Akita Prefecture, Akita (Japan)

2003-01-01

123

Chemical Changes During Pelletising of Brown Coal Ash  

International Nuclear Information System (INIS)

[en] Investigation has been made of the pelletising properties of ash from the combustion of three Victorian brown coals. The Moessbauer spectra showed that the pozzolanic reaction of the calcium aluminoferrite to form ferrihydrite and hydrogarnet was the principal determinant of the pellet strength and ash without this phase did not form strong pellets.

2002-01-01

124

Determination of ash-forming elements in lignite coal  

International Nuclear Information System (INIS)

The most important methods are discussed suitable for the determination of ash-forming elements in coal. In this connection questions of the concentrations of elements in lignites, of the sample preparation, and of the selection of methods for the determination of ash-forming elements are addressed. Advantages and disadvantages of different analysis techniques are shown using concrete examples. (author).

1990-01-01

125

A rapid method of estimation of phosphorus in coal ash  

Energy Technology Data Exchange (ETDEWEB)

The method consists in the extraction of phosphorus from coal ash by treatment with concentrated nitric acid containing an optimum proportion of ammonium nitrate followed by precipitation of phosphomolybdate and its estimation in the usual manner. The use of ammonium nitrate in combination with nitric acid selectively extracts phosphorus from coal ash or other selective phosphatic minerals keeping silica in insoluble form. Thus the laborious step of hydrofluorisation involving the use of costly platinum wares is avoided.

Banerjee, D.D.

1981-11-01

126

Improvements in or relating to coal ash monitors  

International Nuclear Information System (INIS)

An improved monitoring system is described for determining the ash content of coal in wagons. Each wagon passes a neutron source and subsequently the intensities of the ?-rays, emitted by the isotopes produced by neutron reactions on the ash-forming elements in the coal, are detected and measured. Interlocks are used to ensure that the neutron source is only operated when a loaded wagon is in the appropriate position. (U.K.).

1980-01-01

127

Beneficiation of coal pond ash by physical separation techniques.  

UK PubMed Central (United Kingdom)

In this study, investigations to develop a beneficiation process for separating coal pond ash into various products were undertaken. To this end, coal pond ash samples with different particle size ranges were tested in terms of their washability characteristics in a float-and-sink analysis. It was found that coal pond ash was heterogeneous in nature consisting of particles that varied in terms of their size and composition. However, it can be made more homogenous using a gravity separation method. Therefore, the possibility of separating coal pond ash was tested on standard equipment typically used for gravity concentration. To increase the separation efficiency, coal ash was separated according to the size of the particles and each size fraction was tested using equipment appropriate for the corresponding sizes. A hindered-settling column and a shaking table were tested for their ability to treat the 1.19 × 0.074 mm size fraction, and a Falcon concentrator was evaluated for its ability to treat the -0.074 mm size fraction. The results showed that various marketable products, such as lightweight aggregate, sand and high-carbon fuel, can be recovered from coal pond ash using simple physical separation techniques.

Lee SJ; Cho HC; Kwon JH

2012-08-01

128

Fly ash of mineral coal as ceramic tiles raw material  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles.

Zimmer, A.; Bergmann, C.P. [Federal University of Rio Grande do Sul, Porto Alegre (Brazil)

2007-07-01

129

Fly ash of mineral coal as ceramic tiles raw material.  

Science.gov (United States)

The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard () regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles. PMID:16540298

Zimmer, A; Bergmann, C P

2006-03-15

130

Fly ash of mineral coal as ceramic tiles raw material.  

UK PubMed Central (United Kingdom)

The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard () regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles.

Zimmer A; Bergmann CP

2007-01-01

131

Environmentally friendly use of non-coal ashes in Sweden.  

UK PubMed Central (United Kingdom)

The Swedish Thermal Engineering Research Institute (Värmeforsk) initiated an applied research program "Environmentally friendly use of non-coal ashes", in 2002. The program aims at increasing knowledge on the by-products of energy production and their application. The goal of formulating technical and environmental guidelines and assessments is a major point of the program, which is supported by about forty authorities and private organisations. The programme has been divided into four areas: recycling of ashes to forests, geotechnical applications, use in landfilling, and environmental aspects and chemistry. Among all results obtained, the following progress is shown: *Evidence for the positive effects of spreading ashes on forest growth. *A proposal for environmental guidelines on the utilisation of ashes in construction. *A handbook for using non-coal fly ashes in unpaved roads. *Technical and environmental assessments of MSWI bottom ashes in road construction. *Development of the use of ashes with municipal wastewater sludge as a cover for landfills and mine tailings. *Use of ashes from bio-fuels in concrete and replacement of cement in stoop mining. *A method to classify those by-products from combustion that have mirror entries in the EWC as a hazardous or non-hazardous compound. The Ash Programme has also made it possible to increase knowledge on ashes as valuable materials, on quality assurance and on markets for recovered materials.

Ribbing C

2007-01-01

132

Environmentally friendly use of non-coal ashes in Sweden.  

Science.gov (United States)

The Swedish Thermal Engineering Research Institute (Värmeforsk) initiated an applied research program "Environmentally friendly use of non-coal ashes", in 2002. The program aims at increasing knowledge on the by-products of energy production and their application. The goal of formulating technical and environmental guidelines and assessments is a major point of the program, which is supported by about forty authorities and private organisations. The programme has been divided into four areas: recycling of ashes to forests, geotechnical applications, use in landfilling, and environmental aspects and chemistry. Among all results obtained, the following progress is shown: *Evidence for the positive effects of spreading ashes on forest growth. *A proposal for environmental guidelines on the utilisation of ashes in construction. *A handbook for using non-coal fly ashes in unpaved roads. *Technical and environmental assessments of MSWI bottom ashes in road construction. *Development of the use of ashes with municipal wastewater sludge as a cover for landfills and mine tailings. *Use of ashes from bio-fuels in concrete and replacement of cement in stoop mining. *A method to classify those by-products from combustion that have mirror entries in the EWC as a hazardous or non-hazardous compound. The Ash Programme has also made it possible to increase knowledge on ashes as valuable materials, on quality assurance and on markets for recovered materials. PMID:17521898

Ribbing, C

2007-05-22

133

The changes of ash fusion temperature as result of coal chemical pretreatment  

Energy Technology Data Exchange (ETDEWEB)

The effects of chemical treatment of coal on the fusion temperature of coal ash were investigated. Coal samples were treated with diluted solutions of hydrochloric acid, ortho-phosphoric acid, sodium hydroxide and calcium hydroxide. The ash fusion temperature was shown to be influenced by ash composition, or content of the main ash-forming oxides. 3 refs., 2 figs., 1 tab.

Korobetskii, I.A.; Ismagilov, M.S.; Shudrikov, E.S. [Clean Coal Technology & Certification Center (COAL-C Ltd.), Kemerovo (Russian Federation)

1999-07-01

134

Growth and elemental accumulation by canola on soil amended with coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO{sub 2} assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits.

Yunusa, I.A.M.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Murray, B.R.; Nissanka, S.P. [University of Technology Sydney, Sydney, NSW (Australia)

2008-05-15

135

Growth and elemental accumulation by canola on soil amended with coal fly ash.  

Science.gov (United States)

To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO2 assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits. PMID:18453446

Yunusa, I A M; Manoharan, V; DeSilva, D L; Eamus, D; Murray, B R; Nissanka, S P

2008-05-02

136

Study on ultra-low ash activated carbon from coal  

Energy Technology Data Exchange (ETDEWEB)

Activated carbons are widely used in modern industrial fields for purification, refinement, recovery and catalysis, etc. The international trade of activated carbon increases by 5% annually, and so does the output, especially in developing countries. Owing to the shortage of vegetable feedstock, the activated carbon products are manufactured more and more from coals. However the quality of the activated carbons from coals is lower than that from vegetable feedstock, therefore the activated carbons from coals are not able to take the place the products from vegetable feedstock completely. One of the problems of coal-based activated carbons is the ash. Nowadays ash is one of the most important indexes in activated carbon trading. Many ways for lowering the ash have been studied, and a now widely-used method is acid-washing. The ash of the activated carbon washed by acid can be lowered to 10%, but it is very difficult to deash further. This paper investigated a new way to deash the activated carbon from coals to an ash level less than 3%, even 1%, depending on the ash of the feed coal. They studied an additive for deashing activated carbons. The additive reacts with the ash in the activated carbon during carbonization and activation, after which the ash can be removed very easily by acid washing. The main components of the additive are nitrates which are blended with an assistant catalyst. The additive not only makes deashing easily carried out but also favors the formation and development of the porosity and decreases the reaction duration of activation markedly. The technique has been tested in an industrial production line. The results are as follows: activation time was decreased by 30%; the ash (just 3.2%) was much lower than common acid-washed products; the surface area reaches more than 1,200 m{sup 2}/g at a lower burnoff (less than 60%) and the cost is decreased by 20% compared with ordinary process.

Zhang Shuangquan Wang Zuna [China Univ. of Mining and Technology, Beijing (China)

1998-12-31

137

Selective electrochemical oxidation of coal in aqueous alkaline electrolyte  

Energy Technology Data Exchange (ETDEWEB)

In this study, the authors report on the selective electrochemical oxidation of coal at room temperature in an alkaline slurry at 1.0 V (vs. SCE) with little or no oxygen production. Electrode activities and selectivities toward coal oxidation and oxygen evolution were determined by monitoring and analyzing anodic and cathodic gas products. The activities of platinum and various nickel surfaces were compared. Results indicate that coal reacts predominantly with OH radicals during the first 300 to 400 C/g of coal at an initial rate of 0.23 A/cm{sup 2} in a slurry containing 14.3 g of coal per liter. After the 400 C/g level is achieved, the rate of coal oxidation begins to decrease, and oxygen evolution becomes appreciable. Coal oxidation continues to greater than 900 C/g coal. The 900 C/g reaction level corresponds to approximately, one electron per six carbon atoms in the coal substrate and exceeds that expected for any type of surface passivation/functionalization, The rate-controlling steps in the coal reaction sequence appear to be OH radical formation on the electrode surface during the first 400 C/g of reaction and contacting of unreacted coal particles with the electrode thereafter. Coal oxidation competes with oxygen evolution, but the latter becomes significant only after the coal substrate has been depleted.

Ahn, S.; Tatarchuk, B.J. [Auburn Univ., AL (United States). Dept. of Chemical Engineering; Kerby, M.C.; Davis, S.M [Exxon Research and Development Labs., Baton Rouge, LA (United States)

1995-03-01

138

Coal and coke - analysis and testing. Coal and coke. Phosphorus. Ash digestion/phosphomolybdovanadate method  

Energy Technology Data Exchange (ETDEWEB)

This Standard sets out a method for the determination of phosphorus in coal and coke, as phosphomolybdovanadate by spectrophotometry. Two alternative methods of sample decomposition are included. This method is also applicable to the determination of phosphorus in coal ash and coke ash.

NONE

2000-01-20

139

Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments  

International Nuclear Information System (INIS)

[en] Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years.

2010-12-15

140

Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments.  

Science.gov (United States)

Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years. PMID:20855159

Mõtlep, Riho; Sild, Terje; Puura, Erik; Kirsimäe, Kalle

2010-08-26

 
 
 
 
141

Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments  

Energy Technology Data Exchange (ETDEWEB)

Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years.

Motlep, Riho, E-mail: riho.motlep@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Sild, Terje, E-mail: terje.sild@maaamet.ee [Estonian Land Board, Mustamaee tee 51, 10621 Tallinn (Estonia); Puura, Erik, E-mail: erik.puura@ut.ee [Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu (Estonia); Kirsimaee, Kalle, E-mail: kalle.kirsimae@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia)

2010-12-15

142

Ash fusion temperatures and the transformations of coal ash particles to slag  

Energy Technology Data Exchange (ETDEWEB)

A mechanistic study is detailed in which coal ash is heated with its shrinkage measured continuously up to a temperature of 1600{degree}C. The temperature corresponding to the rapid rate of shrinkage correspond to the formation of eutectics identified on phase diagrams. Samples were therefore heated to these temperatures, cooled rapidly and examined using a scanning electron microscope (SEM) to identify the associated chemical and physical changes. The progressive changes in the range of chemical composition (from SEM), the extent of undissolved ash particles and porosity were then quantified and related to homogenisation, viscosity and ash fusion mechanisms. Alternate ash fusion temperatures based on different levels of shrinkage have also been suggested to characterise the ash deposition tendency of the coals. 13 refs., 9 figs.

Gupta, S.K.; Wall, T.F.; Creelman, R.A.; Gupta, R.P. [University of Newcastle, Newcastle, NSW (Australia). CRC for Black Coal Utilisation

1998-07-01

143

Coal Ash Corrosion Resistant Materials Testing  

Energy Technology Data Exchange (ETDEWEB)

In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a moderate alkali content (0.2% sodium equivalents), thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that aggressive alkali sulfate constituents were present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. Test Section A was removed in November 2001 after about 24 months of service at the desired steam temperature set point, with about 15.5 months of exposure at full temperature. A progress report, issued in October 2002, was written to document the performance of the candidate alloys in that test section. The evaluation described the condition of each tube sample after exposure. It involved a determination of the rate of wall thickness loss for these samples. In cases where there was more than one sample of a candidate material in the test section, an assessment was made of the performance of the alloy as a function of temperature. Test Sections B and C were examined during the November 2001 outage, and it was decided that, due to excessive wastage, certain tube samples needed to be removed and replaced in order to ensure that Test Sections B and C would have a chance of remaining in the boiler for their intended exposure period. These suspect tube samples were replaced and the two remaining test sections were put back into service. The tube samples that were removed from Test Sections B and C were set aside for later analysis at the end of the planned exposure period. Test Sections B and C were again examined approximately six months later. At that time, measured wall thickness losses raised concerns about additional tube samples. These suspect samples were also removed, set aside for later analysis, and replaced. The test sections then went back into service until the end of the second exposure period, which was concluded in May 2003 when, due to evidence of excessive wastage, the valves were opened increasing cooling steam flow and thereby effectively stopping corrosion. In August 2003, Test Sections B and C were removed for closer examination. Section C had experienced about 42 months of service at the desired team temperature set point with 28.5 months at temperature at full temperature. Additional suspect samples were removed from Test Section B, then, it was re-installed into the boiler (at the location originally occupied by Section C), where it remained in service until the end of the program. Due to this removal history, the samples from Test Section B had a total service duration that varied from a minimum of 15.5 months (for samples that performed poorly) to 37 months for samples the survived for the full intended service exposure for Section B. The figure below shows a schematic of Test Section B and indicates the length of service exposure for different locations. This report provides the results of the evaluation of Test Section B, including the samples that remained in the Test Section for the full exposure period as well as those that were removed early. This report also is intended to compare and summarize the results for all three test sections. The analysis of T

D. K. McDonald; P. L. Daniel; D. J. DeVault

2007-12-31

144

Thermal conductivity of coal ashes and slags  

Energy Technology Data Exchange (ETDEWEB)

Generally, heat in solids is conducted by the free electrons in metals and alloys at low temperatures, by thermal vibrations of atoms that are observed in the stoichiometric dielectrics, by the free electrons and holes as well as lattice vibrations at the sufficiently high temperatures recorded in semiconductors, and also by ions in amorphous materials at high temperatures. In our case, the linear variations of both thermal and electrical conductivities suggest also that ionization of point defects related to nonstoichiometry, impurities, and dopants plays some role in the thermal conductivity at intermediate and high temperatures. They create free carriers, such as electrons and holes, with concentrations that increase with temperature. The magnitude of this electronic component of thermal conductivity is very low, since {sigma}/k is about 10{sup {minus}6}. Also, there is reason to expect the existence of electrically charged ceramic particles in a liquid-phase sintering medium that may introduce free charges. The ionic component in heat transfer, related to the diffusion of alkali ions, does not play any major role in this range of temperature and can be neglected. This component may take place above some critical temperature, across the surface, or through the volume of the material and is strongly dependent on the glass structure. Figure 7 shows the effect of porosity on the thermal conductivity of Beulah coal ash. Thermal conductivity decreases with the increase of porosity.

Steadman, E.N.; Benson, S.A.; Nowok, J.W.

1992-12-01

145

Preparation and characterization of carbon-enriched coal fly ash  

Digital Repository Infrastructure Vision for European Research (DRIVER)

9 pages, 8 figures, 5 tables.-- PMID: 17826888 [PubMed].-- Available online Sep 10, 2007. , Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Siev...

Rubio Villa, Begoña; Izquierdo Pantoja, María Teresa; Mayoral Gastón, María del Carmen; Bona, M. T.; Martínez Tarazona, M.ª Rosa

146

Chemical modification of coal fly ash for the removal of phosphate from aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

This study investigated the chemical modifications of coal fly ash treated with HCl and NaOH. Sorption behavior of phosphate from water solution on treated fly ash was examined. Results showed that the HCl-treated fly ash (TFA-HCl) had a greater specific surface area (SSA) than the NaOH-treated fly ash (TFA-NaOH) and untreated fly ash (FA). The XRF, XRD patterns, and SEM images revealed the decreased CaO content in the TFA-HCl and observed the presence of NaP1 and sodalite zeolites in the TFA-NaOH. The P sorption capacity of all studied fly ashes increased with increasing initial P concentration and mechanisms of P sorption were influenced by the equilibrium pH. Maximum phosphate immobilization capacity obtained from Langmuir model was in the following manner, TFA-NaOH > FA > TFA-HCl (57.14, 23.20, and 6.90 mg P g{sup -1}, respectively). The decreased CaO content and acidic pH in the TFA-HCl were responsible for the lowest capacity of phosphate immobilization, because of unfavorable condition for calcium phosphate precipitation. In contrast, due to alkaline condition and relatively high calcium content, the precipitation of calcium phosphate was a key mechanism for phosphate removal in the FA and TFA-NaOH. The TFA-NaOH had a greatest phosphate immobilization, due to high CaO content and an increased SSA after the conversion of fly ash to zeolite. Both Langmuir and Freundlich models were good fitted for the TFA-NaOH, while was only Langmuir model for the FA and Freundlich model for the TFA-HCl. Results suggested that treating fly ash with alkaline solution was a promising way to enhance phosphate immobilization. 23 refs., 7 figs., 2 tabs.

P. Pengthamkeerati; T. Satapanajaru; P. Chularuengoaksorn [Kasetsart University, Bangkok (Thailand). Environmental Technology Research Unit (EnviTech), Department of Environmental Science

2008-09-15

147

Application of a new ash fusion test to Theodore coals  

Energy Technology Data Exchange (ETDEWEB)

The standard ash fusion test is criticised widely due to its subjective nature. Interlaboratory exercises showed that operators could differ up to 400{degree}C in initial deformation temperature determination in the standard ash fusion test. The improved ash fusion test proved to be a useful tool to resolve ambiguous results from the standard ash fusion test. Good correlations were found between the ash chemistry and major movement temperatures in the new ash fusion test for this data set. Moreover, initial deformation as well as spherical and flow temperatures from the standard ash fusion test showed good correlations with major movement and 85% movement temperatures from the new ash fusion test for this data set. A coal washing exercise showed that ash fusion temperatures in the new test improved significantly. Further, ply blending was found to alter the ash fusion characteristics. Major movement temperatures from the improved ash fusion test were found to be additive in ply blending. 13 refs., 7 figs., 1 tab.

Kahraman, H.; Bos, F.; Reifenstein, A.; Coin, C.D.A [ACIRL Ltd., Booval, Qld. (Australia)

1998-09-01

148

Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey  

International Nuclear Information System (INIS)

Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained 226Ra (coal samples: 89-148 Bq kg-1; ash samples: 15-26 Bq kg-1), 238U (coal samples: 2-4 ?g g-1; ash samples: 9-33 ?g g-1), 232Th (coal samples: 1-9 ?g g-1; ash samples: 8-12?g g-1), and 40K (coal samples: 26-67 Bq kg-1; ash samples: not detected). 134Cs and 137Cs have not been found in the samples. (author)

1999-01-01

149

Enhanced HCl sorption with hydrated coal burnt ash  

Energy Technology Data Exchange (ETDEWEB)

The applicability of hydrated coal burnt ashes as dry gas sorbents for enhanced HCl removal was experimentally studied. In this work, three kinds of coal burnt ash discharged from fluidized bed coal combustion were hydrated with deionized water and with solutions of alcohols such as methanol, ethanol, diethylene glycol, propylene glycol and glycerin at 273 to 353 K. The hydrated sorbent was tested for HCl removal in a fixed bed reactor under simulated conditions of flue gas capture for a municipal waste incinerator (473 K, 1,000 ppmv HCl). It was found that the improvement of HCl sorption was large with higher CaO content in the hydrated coal burnt ash. The increase in the HCl sorption capacity of coal burnt ash increased with hydration temperature. Maximum HCl sorption as obtained with hydration using glycerin. XRD results showed the generation of Ca(OH){sub 2} with higher crystallinity after hydration. Hydration of coal ash caused remarkable increase in surface area of pore, between 0.001 {mu}m and 0.01 {mu}m, which played a significant role in high HCl sorption.

Hirabayashi, D.; Saito, Y.; Ozawa, S.; Matsuda, H.; Tanahashi, N. [Nagoya University, Nagoya (Japan)

2002-11-01

150

Utilisation of coal ash to improve acid soil  

Directory of Open Access Journals (Sweden)

Full Text Available The study on utilization of coal ash to improve acid soil was carried out in a greenhouse at the Land Development Regional Office 1, Pathum Thani Province, Central Thailand, from January-May 2003. Fly ash mixture (fly ash plus gypsum and lime at the proportion 5:4:1) and clinker ash mixture (clinker ash plus gypsum and lime at the proportion 5:4:1) were used as soil amendments at varying rates i.e., 0, 6.25,12.5, 18.75 and 25 t/ha to improve the soil. The aim of this study was to determine the effect of application of coal ash on acid soil and the growth of a vegetable (Chinese kale). Chinese kale cultivars were planted in a randomized complete block design with three replications. Pak Chong soil series (Ultisols) was used as the growth medium. Twenty-day-old seedlings were transplanted in 270 pots (two plants per pot) containing acid soil with different treatments of coal ash mixture which were as follows: 1) control, 2) fly ash mixture 6.25 t/ha, 3) fly ash mixture 12.5 t/ha, 4) fly ash mixture 18.75 t/ha, 5) fly ash mixture 25 t/ha, 6) clinker ash mixture 6.25 t/ha, 7) clinker ash mixture 12.5 t/ha, 8) clinker ash mixture 18.75 t/ha and 9) clinker ash mixture 25 t/ha. Chemical fertilizers were applied at the rate of 250 kg/ha using a grade of 15-15-15 of N, P and K, respectively. Plants were harvested 40 days after transplanting. Among the treatments, application of fly ashmixture at a rate of 25t/ha (4t/rai) substantially increased soil pH up to 5.7. Fly ash was found more effective than clinker ash in increasing soil pH. The highest yield of Chinese kale was also obtained when fly ash mixture was applied at a rate of 25 t/ha followed by fly ash mixture at 18.75 t/ha and clinker ash mixture at 18.75 t/ha with an average yield per plant of 4.980, 3.743 and 3.447 grams, respectively. It can be concluded that the application of coal ash mixture, either fly- or clinker ash, at 18.75-25 t/ha (3-4 t/rai) was the most effective in terms of plant yield. The use of coal ash mixture increased cation exchange capacity, base saturationpercentage and Ca, Mg and S contents in the soil as well as plant uptake of N. The concentrations of heavy metals in the soil (Cd, As, Co, Cr, Cu, Hg, Ni, Pb and Zn) were found to be within permissible levels while Cd, Cr and Ni in the plants were at critical levels for health.

Rungsun Im-Erb; Noparat Bamroongrugsa; Koji Kawashima; Tomoyuki Amano; Shigeru Kato

2004-01-01

151

Chemical composition and some trace element contents in coals and coal ash from Tamnava-Zapadno Polje Coal Field, Serbia  

Energy Technology Data Exchange (ETDEWEB)

The chemical compositions and trace element contents (Zn, Cu, Co, Cr, Ni, Pb, Cd, As, B, Hg, Sr, Se, Be, Ba, Mn, Th, V, U) in coal and coal ash samples from Tamnava-Zapadno Polje coal field in Serbia were studied. The coal from this field belongs to lignite. This high volatility coal has high moisture and low S contents, moderate ash yield, and high calorific value. The coal ash is abundant in alumosilicates. Many trace elements such as Ni > Cd > Cr > B > As > Cu > Co > Pb > V > Zn > Mn in the coal and Ni > Cr > As > B > Cu > Co = Pb > V > Zn > Mn in the coal ash are enriched in comparison with Clarke concentrations.

Vukasinovic-Pesic, V.; Rajakovic, L.J. [University of Montenegro, Podgorica (Montenegro)

2009-07-01

152

Continuous ash monitoring of ROM coal using radioactive sources  

International Nuclear Information System (INIS)

After the positive results obtained in processing plants with radioactive radiation sources for continuous measurement and control of the ash content of coking coal, attempts were made to extend their range of applications to raw coal. Simultaneously with measurements of the dirt content, the total amount of material transported on a belt conveyor will be measured. Further, bulk density and mean grain size of the coal will be determined. Activities in this field in the Seventies are reviewed. (orig.)

1981-01-01

153

Arsenic and nickel enrichment coefficients for crops growing on coal ash  

Energy Technology Data Exchange (ETDEWEB)

Around the city of Tuzla, BiH soil covered coal ash disposal sites have been used for food and fodder production since 1992. To our knowledge this is the first report on the cultivation of coal ash disposal sites for agriculture purposes. We observed high concentrations of As and Ni in alkaline coal ash. In this paper, we investigated arsenic and nickel transport and accumulation in barley and soybean grown on substrates made up of different soil and ash ratios. After three growth in the greenhouse we observed significant differences (p<0.05) between the Ni enrichment coefficients of Dora cultivar of soybean and Rex cultivar of barley, but no significant difference between the As enrichment coefficients of soybean and barley. Dora cultivar of soybean and Rex cultivar of barley showed very low uptake of arsenic, the enrichment coefficient varied between 0.05% and 0.51% depending on the crop and the treatment. The nickel enrichment coefficient of Rex cultivar of barley varied between 0.01% and 0.94%. The enrichment coefficient for Ni in Dora cultivar of soybean indicated higher uptake and varied between 5.64%, and 34.79%.

Zgorelec, Z.; Basic, F.; Kisic, I.; Wenzel, W.W.; Custovic, H. [University of Zagreb, Zagreb (Croatia)

2008-07-01

154

Microwave-assisted zeolite synthesis from coal fly ash in hydrothermal process  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ashes, which include much amount of silica and alumina, can be converted into zeolite by hydrothermal alkaline treatment. In the present work, the effect of microwave irradiation on the zeolite formation was investigated with emphasis on the change in yield of zeolite during the reaction. The fly ash was mixed with 2 M NaOH solution and heated by oil bath or microwave for 2 h. Zeolite Na-P1 formed after the conventional treatment using oil bath, but no zeolitic product was obtained by microwave heating. When microwave was applied in the course of hydrothermal treatment, zeolitization was promoted by the early-stage irradiation. This is due to the stimulated dissolution of SiO{sub 2} and Al{sub 2}O{sub 3} from coal fly ash. On the other hand, the microwave irradiation in the middle to later stage retarded the crystallization of zeolite. The microwave is effective to produce the zeolite from coal fly ash in a short period by control of irradiation schedule in the early stage. 8 refs., 6 figs., 1 tab.

Miki Inada; Hidenobu Tsujimoto; Yukari Eguchi; Naoya Enomoto; Junichi Hojo [Kyushu University, Fukuoka (Japan). Department of Chemistry and Biochemistry, Graduate School of Engineering

2005-09-01

155

Effect of the Hyper-coal (ash-free coal) addition to coal on coke strength  

Energy Technology Data Exchange (ETDEWEB)

Hyper-coal(HPC), which is an ash free coal, can be produced by thermal extractions with organic solvents and separation from the insoluble residue (by the gravity settling and/or the filtration). We estimated the HPC as a coke making material in this report. We obtained various coke samples by carbonization of blended coal containing the HPC, and measured the coke strength as an I-type drum index (IDI). A little addition of the HPC into coal improved the coke quality (IDI). We confirmed that we could substitute some amount of poorly-coking coal for strongly-coking coal without change of the coke IDI. 4 refs., 4 figs., 2 tabs.

Kanji Matsudaira; Yuko Nishibata; Masaru Nishimura; Noriyuki Okuyama; Takuo Shigehisa [The Kansai Coke & Chemicals Co., Ltd., Hyogo (Japan). Research and Development Center

2005-07-01

156

COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS; TOPICAL  

International Nuclear Information System (INIS)

[en] The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems

2001-01-01

157

COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS  

Energy Technology Data Exchange (ETDEWEB)

The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems.

Christopher J. Zygarlicke; Donald P. McCollor; Steven A. Benson; Jay R. Gunderson

2001-04-01

158

Radioactivity of coal ash used in building materials  

International Nuclear Information System (INIS)

[en] In Germany every year about 18 million tonnes of combustion by-products are produced in coal-fired power stations. In 1996 these by-products were boiler slag (about 3 million tonnes), bottom ash (about 3 million tonnes) and above all fly ash (about 12 million tonnes). 7.5 million tonnes result from the burning of bituminous coal and 10.3 million tonnes from lignite. About 98 % of the bituminous coal ash is used in construction and mining industry. The majority of lignite ash is used for the filling and re cultivation of open pit mines, it is utilized either unmixed or mixed with FGD ( flue-gas desulfurization) gypsum and FGD water. The natural radioactivity of coal and also of the ash mainly results from many natural radionuclides in the decay series of uranium-radium, thorium and to an insignificant extent of uranium-actinium, as well as from potassium-40. Because of the age of coal, the activity concentrations of the different radionuclides are in a radioactive equilibrium. 'Therefore it is sufficient to consider the significant radionuclides for the radiation doses in each natural decay series, namely radium-226 and thorium-232 with their daughters radon-222 and radon-220 and also potassium-40. lie contribution of the radionuclides of the uranium-actinium series to the radiation dose can be neglected. (authors)

1997-11-16

159

Fundamental study on release of coal ash components in the coal gasifier  

Energy Technology Data Exchange (ETDEWEB)

It is significant to clarify release characteristics of ash components and condensing behavior of released components in high pressure reducing atmosphere, because these behaviors affect on coal ash properties and change the slagging and fouling characteristics in gasifier. Three brands of pulverized coal were burnt following JLS (Japanese Industrial Standards) regulation to form ash samples, and prepared ash was exposed to hydrogen/argon mixture reducing gas(hydrogen 3%) at temperature ranging from 600 C to 1,460 C for about 2 hours in electric tube furnaces at atmospheric pressure and 900kPa. By analyzing the composition of each sample by XRF, release characteristics of each component was clarified. To obtain referring data, CCSEM analysis was performed. In this paper, the change of ash composition at the temperature in the reductor of gasifier was quantified. The effect of coal brand and pressure on ash composition was found to be remarkable.

Oki, Yuso; Inumaru, Jun

1999-07-01

160

Development of high-performance coal gasification technology for high ash fusion point coals by coal blending method  

Energy Technology Data Exchange (ETDEWEB)

Coals with higher ash fusion temperatures tend to have lower gasification performances owing to the operation at higher air ratios, since more air is necessary to keep higher temperatures in the entrained flow coal gasifier. Since coal blending method can lower the ash fusion temperature, it is possible to gasify high ash fusion point coals at high efficiency. This report presents the behaviour of ash fusion temperature by blending coal and the test results of blended coal gasification in a 2T/D bench scale air-blown pressurized entrained flow coal gasifier. As a result, it was confirmed that it was possible to decrease the ash fusion point of a high ash fusion point coal from 1750{degree}C to 1400{degree}C by blending a low ash fusion point coal, and to improve the gasification performances by reducing the amount of air into the gasifier. Operation performances such as slagging characteristics and handling of coal and char were improved.

Inumaru, J. (and others) (CRIEPI, Yokosuka-shi (Japan). Yokosuka Research Lab.)

1991-01-01

 
 
 
 
161

Method for determining the ash content of coal  

International Nuclear Information System (INIS)

[en] The described method allows to determine the ash content of coal of varying composition with regard to the combustible constituent by combined beta and X-ray backscattering measurements. The intensities of the incident beta and X radiation are adjusted in such a way that the obtained signal resulting from the joint detection of the backscattered radiations depends to as high a degree as possible only on the ash content

1983-10-21

162

Study of agglomeration of coal-ash in fluidized beds  

Energy Technology Data Exchange (ETDEWEB)

Experimental data on agglomeration of coal-ash particles in a fluidized bed are presented. Above the initial sintering temperature, the ash particles are defluidized at velocities above their minimum fluidization velocity. The expression for minimum fluidization velocity is modified by including a force-term due to the phenomenon of sintering in addition to those due to drag, gravity, and kinetic energy. (8 refs.)

Basu, P.

1982-12-01

163

Fly ash and concrete: a study determines whether biomass, or coal co-firing fly ash, can be used in concrete  

Energy Technology Data Exchange (ETDEWEB)

Current US national standards for using fly ash in concrete (ASTM C618) state that fly ash must come from coal combustion, thus precluding biomass-coal co-firing fly ash. The co-fired ash comes from a large and increasing fraction of US power plants due to rapid increases in co-firing opportunity fuels with coal. The fly ashes include coal fly ash, wood fly ash from pure wood combustion, biomass and coal co-fired fly ash SW1 and SW2. Also wood fly ash is blended with Class C or Class F to produce Wood C and Wood E. Concrete samples were prepared with fly ash replacing cement by 25%. All fly ash mixes except wood have a lower water demand than the pure cement mix. Fly ashes, either from coal or non coal combustion, increase the required air entraining agent (AEA) to meet the design specification of the mixes. If AEA is added arbitrarily without considering the amount or existence of fly ash results could lead to air content in concrete that is either too low or too high. Biomass fly ash does not impact concrete setting behaviour disproportionately. Switch grass-coal co-fired fly ash and blended wood fly ash generally lie within the range of pure coal fly ash strength. The 56 day flexure strength of all the fly ash mixes is comparable to that of the pure cement mix. The flexure strength from the coal-biomass co-fired fly ash does not differ much from pure coal fly ash. All fly ash concrete mixes exhibit lower chloride permeability than the pure cement mixes. In conclusion biomass coal co-fired fly ash perform similarly to coal fly ash in fresh and hardened concrete. As a result, there is no reason to exclude biomass-coal co-fired fly ash in concrete.

Wang, Shuangzhen; Baxter, Larry

2006-08-01

164

Production of ceramics from coal fly ash  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa) and sintering (950, 1000...

Angjusheva Biljana; Fidancevska Emilija; Jovanov Vojo

165

Properties of Concrete using Tanjung Bin Power Plant Coal Bottom Ash and Fly Ash  

Directory of Open Access Journals (Sweden)

Full Text Available Coal combustion by-products (CCPs) have been around since man understood that burning coal generates electricity, and its utilization in concrete production for nearly a century. The concept of sustainable development only reawaken our consciousness to the huge amount of CCPs around us and the need for proper reutilization than the current method of disposal which has  severe consequences both to man and the environment. This paper presents the result of utilization of waste from thermal power plants to improve some engineering properties of concrete. Coal bottom ash (CBA) and fly ash were utilized in partial replacement for fine aggregates and cement respectively. The results of compressive strength at 7, 28, 56 & 90 days curing are presented because of the pozzolanic reaction. Other properties investigated include physical properties, fresh concrete properties and density. The results showed that for a grade 35 concrete with a combination of CBA and fly ash can produce 28 day strength above 30 MPa.

Abdulhameed Umar Abubakar; Khairul Salleh Baharudin

2012-01-01

166

Coal ash in Israel: Natural resource or environmental hazard  

Energy Technology Data Exchange (ETDEWEB)

Coal combustion in Israeli power plants produces 1,000,000 tonnes of ash annually. Most of the ash (55%) is used as cement additive. Since the expansion of coal combustion is much faster than the development of cement production, large amounts of fly ash are expected to accumulate in the next decade. Thus the environmental problem may be exacerbated if other means of utilization (e. g. embankments and marine reclamation or utilization as a chemical reagent) will not be possible in the future. Unlike other countries overseas, coal ash is defined in Israel as hazardous material, thus any disposal or utilization scheme requires a special permit. The main concern is that pollution from the ash will leach out and contaminate the proximal ground water. The authors have decided to check the leaching behavior of South-African and Colombian fly ashes (the most abundant in Israel) using the following methods: (a) the improved EPA-TCLP 1311 (used in the US); (b) the EU-CEN/TC292/WG2 (declared recently as the method in the European Community); and (c) the NVN2508 method. The first two methods are batch methods and the third a flow through column method. The main constituents of the ash are listed along with the trace elements found. It has been observed that no appreciable amount of most trace elements are dissolved from the ash except that of chromium which exceeds the drinking water limits. Furthermore most of the leached chromium is in the hexavalent form which is considered as carcinogenic. The effect of different parameters and the risk involved in leaching out of trace elements from the fly ash to the underground water aquifer will be discussed in detail.

Sheps, S.; Davidi, S. [Ben-Gurion Univ. of the Negev (Israel); Cohen, H. [Ben-Gurion Univ. of the Negev (Israel)]|[NRCN, Beer-Sheva (Israel)

1997-12-31

167

Radioisotope instrument for monitoring ash content of coal concentration products  

International Nuclear Information System (INIS)

[en] The PRZ-7605 radioisotope instrument for monitoring the ash content of coal concentration products was developed for operational monitoring of fuel ash content. The ash meter is intended for continuous and contactless measurement of ash content on a conveyor belt in the range from 5 to 35%; at an ash content of less than 10% the absolute error is ±0.8%, at an ash content of 10-35% - no more than ±0.08%. The instrument has two measurement subranges: from 5 to 20 and from 20 to 35% and carries out periodic control of the stability of the ash content readings on a built-in reference sample. The size of the fuel pieces should not exceed 100 mm. The minimal admissible thickness of the bed of material on the conveyor is ? 100 mm. The duration of one measurement cycle is 2 seconds with integration of the output value for fuel ash content from 1 to 10 minutes with a discreteness of 1 minute. The measurement results in the form of a continuous dc electric signal in the range from 0 to 5 or from 4 to 20 mA, and also in the form of a 16-digit binary-decimal code can be sent to a control computer or to secondary recording instruments. The information concerning ash content is output to a four-digit decimal display

1990-01-01

168

Recovery of iron oxide from coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

Dobbins, Michael S. (Ames, IA); Murtha, Marlyn J. (Ames, IA)

1983-05-31

169

Characterization of mutagenic coal fly ash and extracts.  

UK PubMed Central (United Kingdom)

Post-electrostatic precipitator (ESP) fly ash samples were collected from a coal-fired electric power generation plant under three modes of plant operation: normal operation, a low NOx-emission mode of combustion, and operation with the ESP shorted-out. Results of chemical and physical characterization of the ashes were compared with bacterial mutagenicity bioassay to determine parameters or compounds correlating with bioactivity. The general physical properties, ultimate composition, and trace elemental and radiochemical species determined did not correlate with the mutagenicity. Only the presence of aromatic hydrocarbons and chemically derivatizable polar organic compounds appeared to be associated with mutagenicity of the fly ash.

Griest WH; Caton JE; Rao TK; Harmon SH; Yeatts LB Jr; Henderson GM

1982-11-01

170

Catalytic activity of alkaline earth carbonates in the gasification of coal chars by carbon dioxide. Deactivation by mineral matters in coal char  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the coal char gasification by CO/sub 2/ using alkaline earth carbonates. The sample char was prepared by making chars in nitrogen atmosphere from four coals with different ranks of coalification and different contents of ash and a phenolic resin free from inorganic salt. Gasification was made in CO/sub 2/ atmosphere at a heating rate of 5/sup 0/C/min in a thermobalance to obtain thermograms. The starting temperature of gasification is decreased and the rate of conversion is increased by adding the alkaline earth carbonates excluding MgCO/sub 3/. The purification activities of chars with higher content of ash are lower than that of phenolic resin, especially at a lower concentration of catalyst. The activity of deashed char is increased only a little due to the remaining ash. Even the activity of the char with higher content of ash is increased by using a higher level of catalyst than a certain level. Since the catalyst reacts with SiO/sub 2/ and Al/sub 2/O/sub 3/ in the ash to produce silicates and aluminosilicates, it is deactivated. This was identified by the X-ray diffractometry and programmed-temperature X-ray diffractometry. (4 figs, 5 tabs, 38 refs)

Yamada, Tetsuo; Asakura, Tadashi; Takahashi, Atsushi; Suzuki, Tsutomu; Honma, Tsuneyuki

1988-03-20

171

Ash fusion temperatures and the transformations of coal ash particles to slag  

Energy Technology Data Exchange (ETDEWEB)

A mechanistic study is detailed in which coal ash is heated with the shrinkage and electrical resistance measured continuously up to a temperature of 1600{degrees}C. The temperatures corresponding to rapid rates of shrinkage are shown to correspond to the formation of eutectics identified on phase diagrams. Samples where therefore heated to these temperatures, cooled rapidly and examined with an SEM to identify the associated chemical and physical changes. The progressive changes in the range of chemical analysis (from SEM), the extent of undissolved ash particles and porosity are then quantified and related to the shrinkage events and standard ash fusion temperatures.

Wall, T.F.; Creelman, R.A.; Gupta, R.; Gupta, S. [Univ. of Newcastle (Australia)

1996-10-01

172

Long-term evaluation of coal fly ash and mine tailings co-placement: a site-specific study.  

Science.gov (United States)

This study presents the results of a laboratory investigation conducted to evaluate the efficiency of coal fly ash to control the formation of acid mine drainage (AMD) from mine waste. Site-specific materials, coal fly ash from Atikokan Thermal Generating Station and mine tailings from Musselwhite mine, were mixed at different proportions for the investigation of the drainage chemistry and the optimal mix using static testing (acid-base accounting) and kinetic (column) testing. The acid-base accounting (ABA) results indicated that the fly ash possessed strong alkaline (neutralization) potential (NP) and could be used in the management of reactive mine tailings, thus ensuring prevention of AMD in the long-term. Column tests conducted in the laboratory to further investigate long-term performance of fly ash in the neutralization and prevention of acid mine drainage from tailings similarly showed that mixing fly ash with mine tailings reduces dissolution of many heavy metals from tailings by providing alkalinity to the system. It was found that a fly ash to tailings mass ratio equal to or greater than 15% can effectively prevent AMD generation from Musselwhite mine tailings in the co-placement approach. PMID:19744768

Yeheyis, Muluken B; Shang, Julie Q; Yanful, Ernest K

2009-09-10

173

Prediction of ash fusion temperature from ash composition for some New Zealand coals  

Energy Technology Data Exchange (ETDEWEB)

Three improved techniques are presented for predicting the fusibility temperatures of coal ash from ash composition for particular coalfields. The first uses ternary equilibrium phase diagrams where the vertices are percent base, percent fluxing acidic oxides and percent non-fluxing acidic oxides. For reducing conditions FeO is a base, but for oxidizing conditions Fe/sub 2/O/sub 3/ is a non-fluxing acid. Plots of ash fusibility results on these diagrams show the range of behaviour of a particular coal and where low temperatures occur. They can be used to predict behaviour of fresh samples. The second method uses multiple regression equations above and below the minimum in the ash fusion temperature-percent base plot (usually 38% base), using as predictors, percent base (B),B/sup 2/, and acid flux and base flux factors F/sub A/,F/sub B/ (or their logarithms). The third technique, the most accurate, uses stepwise regression, again on split observations above and below the minimum in the ash fusion temperature-percent base plot. With 40 parameters it is possible to identify the significant ash fusion parameters present for each fusion measurement in each coalfield. Two sets of observations which included measurements of borate (B/sub 2/O/sub 3/) showed that it caused a significant but negligible reduction in ash fusion temperature. 28 refs., 4 figs., 2 tabs.

Gray, V.R.

1987-09-01

174

Coal ash composition of Australian low rank coals  

Science.gov (United States)

The iron-containing phases in nine precipitator ashes of widely differing composition have been analyzed by57Fe Mössbauer spectroscopy. The importance of the relative proportion of calcium ferrite to magnesioferrite in determining the ash fusion characteristics was established and a procedure developed which reproduced the observed proportion, starting from the ash chemical analysis data.

Brown, L. J.; Cashion, J. D.; Ledger, R. C.

1992-04-01

175

Research into the utilization of coal ash as a civil engineering material (IX): the density, fluidity and strength of coal ash/volcanic ash/cement slurries  

Energy Technology Data Exchange (ETDEWEB)

The authors report tests of the effect of the addition of sandy soil to coal ash slurries. Specifically, volcanic ash, cement and sea-water were kneaded with wet fly ash and measurements made of slump and unconfined compression strength (qu). The following findings are reported. 1) Qu decreased with increasing void ratio. 2) Qu increased with increasing proportion of coal ash in the slurry. 3) The various constituent materials began to separate when more than 60% volcanic ash was added. 4) To be a satisfactory material for incorporation into soil structure, slurries of the sort under test should have a wet density of 1.7 g/cm/sup 3/, an unconfined compression strength of 3 kgf/cm/sup 2/, and a slump value of 12 cm. 3 references, 6 figures, 1 table.

Horiuchi, S.; Onoue, A.; Yamada, S.

1986-01-01

176

Determination of the ash content of coal using annihilation radiation  

International Nuclear Information System (INIS)

[en] The ash content of coal can be determined by a simple technique based on the simultaneous measurement of 0.511 MeV annihilation radiation and Compton scattered radiation which result from irradiation of a coal sample with ?-rays of energy > 1.022 MeV. The technique has been tested by many laboratory measurements on 57 bulk coal samples, each weighing 100-200 kg, from three different areas of Australia. These measurements were performed using a 60Co source and 7.6 cm x 7.6 cm NaI(T1) detector in a backscatter geometry. The r.m.s. deviations between chemical laboratory ash and ash measured on the backscatter gauge were in the range of 0.46 to 1.37 wt.%. Compared with X-ray methods of ash analysis which depend on a single measurement proportional to the mass absorption coefficient, the annihilation radiation method has the advantages of less sensitivity to high Z elements such as Fe and Ca, less sensitivity to moisture variations and potentially greater depth penetration because of the higher energies used. The main potential applications of the technique are for the continuous analysis of coal on conveyor belts, in chutes or in hoppers. Such analysis is required mainly for the control of coal washeries and blending operations. (orig.)

1981-09-15

177

Process for removing ash from coal  

Energy Technology Data Exchange (ETDEWEB)

Mineral impurities can be effectively removed from coal by introducing oil droplets into an aqueous slurry of pulverized coal. Coal, which is lipophilic, attaches to the surface of the oil droplets and floats upwardly along with the oil droplets utilizing their buoyancy. On the other hand, mineral impurities, which are hydrophilic, are left in the aqueous slurry.

Akimoto, H.; Hishinuma, Y.; Kaji, R.; Kikuchi, H.; Komuro, T.; Muranaka, J.; Nakajima, Y.; Terada, H.

1984-06-26

178

Coal-ash spills highlight ongoing risk to ecosystems  

Energy Technology Data Exchange (ETDEWEB)

Two recent large-scale spills of coal combustion waste have highlighted the old problem of handling the enormous quantity of solid waste produced by coal. Both spills happened at power plants run by the Tennessee Valley Authority (TVA). In December 2008 a holding pond for coal ash collapsed at a power plant in Kingstom, Tenn., releasing coal-ash sludge onto farmland and into rivers: in January 2009 a break in a pipe removing water from a holding pond for gypsum caused a spill at Widows Creek Fossil Plant in Stevenson, Ala. The article discusses the toxic outcome of such disasters on ecosystems, quoting work by Willaim Hopkins at Virginia Polytechnic Institute and State University and recommendations and reports of the US EPA. 2 photos.

Chatterjee, R.

2009-05-01

179

Alkaline leaching of coal by the mechanochemical treatment  

Directory of Open Access Journals (Sweden)

Full Text Available The possibility of application of a new process GACL (Grinding and Aqueous Caustic Leaching) for the reduction of mineral components in the brown coal Nováky was tested. The simultaneous grinding and chemical leaching enable us to extract 41 % total sulphur, 95 % arsenic and to reduce the ash content to 43 %. The process proceeds at the atmospheric pressure, temperature 90oC and in diluted NaOH solutions (5 %).

Balá? Peter; Turèániová ¼udmila

1998-01-01

180

Determination of trace elements in coal and coal ash samples by ICP-MS  

Energy Technology Data Exchange (ETDEWEB)

The determination of several trace elements, including thorium and the lanthanides in coal and coal ashes applying total dissolution and ICP-MS, was studied. The procedures were tested with reference materials (Bituminous Coal NIST 1632a and Fly Ash NIST 1633a). For coal samples, chemical ashing with HNO{sub 3}, HF, and HClO{sub 4} produces reasonable results. For coal ash samples, some difficulties related to the determination of rubidium, cesium, thorium, and the lanthanides were found and a proposed solution is discussed. Finally, coal, bottomash, electrostatic precipitator (ESP), and fly ash samples from a Brazilian coal-fired power plant were analyzed and an enrichment of Mn, Zn, Ge, As, Se, Mo, Cd, Sb, Ag, Pb, Bi, and U in fly ash was observed. The values obtained for refractory elements, such as thorium, cerium, and scandium, in the ESP samples were compared with those obtained by INAA, with good agreement between both results. The use of a large number of elements (57) during the instrument calibration allows the use of the TotalQuant mode as a routine method.

Godoy, M.L.D.P.; Godoy, J.M.; Roldao, L.A. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

2001-07-01

 
 
 
 
181

The reaction of acid mine drainage with fly ash from coal combustion  

Energy Technology Data Exchange (ETDEWEB)

The placement of alkaline fly ash in abandoned, reclaimed or active surface coal mines is intended to reduce the amount of acid mine drainage (AMD) produced at such sites by neutralization, inhibition of acid forming bacteria, encapsulation of the pyrite or water diversion. A continuing concern with this application is the potential release of trace elements from the fly ash when it is placed in contact with AMD. To investigate the possible release of antimony, arsenic, barium, boron, cadmium, chromium, cobalt, copper, lead, nickel, selenium, and zinc from fly ash, a series of column leaching tests were conducted. A one kg fly ash sample, placed in a 5-cm by 1 m acrylic columns, was leached at a nominal rate of 250 mL/d for between 30 and 60 days. The leachant solutions were deionized water, and dilute solutions of sulfuric acid and ferric chloride. Leaching tests have been completed on 28 fly ash samples. leachate data, analyzed as the mass extracted with respect to the concentration in the solid, indicate that the release of trace elements is variable, with only barium and zinc extracted at greater than 50 pct of the amount present in the original sample. As a comparison, water quality changes have been monitored at three sites where fly ash grout was injected after reclamation to control AMD. When compared before and after grouting, small increases in pH and decreases in acidity at discharge points were observed. Concentrations of trace metals were found to be comparable in treated and untreated areas. When grouted and ungrouted areas were compared, the effect of the fly ash was shown to be localized in the areas of injection. These studies indicated that when fly ash is used as a reagent to control of AMD, the release of trace elements is relatively small.

Kim, A.G.

1999-07-01

182

Fusibility and flow properties of coal ash and slag  

Energy Technology Data Exchange (ETDEWEB)

We studied the fusibility and flow properties of laboratory ash and Shell gasifier slag from the same coal sample (Chinese Huainan coal). The physical properties of ash and slag were analyzed with X-ray fluorescence, X-ray diffraction, and scanning electron microscopy. The fusion temperature and the experiment viscosity were measured for the ash and slag with the addition of fluxing CaO. Ash and slag have properties that were approximated by the SiO{sub 2}-Al{sub 2}O{sub 3}-'FeO'-CaO system. The computer software package FactSage was used to predict the proportion of solid phase and the mineral phase formed as a function of the composition and the temperature of the SiO{sub 2}-Al{sub 2}O{sub 3}-'FeO'-CaO system. The results show that the fusion temperatures and the temperature of critical viscosity (Tcv) of ash are always higher than that of slag. Also, the viscosity of ash is always higher than that of slag at the slag tapping temperature range of 1400-1500{sup o}C, and the hysteresis between the heating and cooling cycles for ash is more obvious than that of slag because of different physical properties. The fusion temperature and Tcv of ash and slag decrease with increasing CaO content, whereas those values increase rapidly with CaO content higher than 35%. Also, the sensitivity of the viscosity of the ash and slag with temperature decreases with increasing CaO content because the sensitivity of the phase equilibria of in the SiO{sub 2}-Al{sub 2}O{sub 3}-'FeO'-CaO system to temperature excursions decreases with increasing CaO content.

Wenjia Song; Lihua Tang; Xuedong Zhu; Yongqiang Wu; Yongqiao Rong; Zibin Zhu; Shuntarou Koyama [East China University of Science and Technology, Shanghai (China). Engineering Research Center of Large Scale Reactor Engineering and Technology

2009-02-15

183

Utilization of Atikokan coal fly ash in acid rock drainage control from Musselwhite Mine tailings  

International Nuclear Information System (INIS)

Acid rock drainage (ARD) is the greatest environmental liability facing the mining industry. Mines produce acidic effluents that are generated from the chemical reaction of sulphide containing minerals and atmospheric oxygen. The effluents have a pH value as low as 2 to 4 and their movement is accompanied by heavy metals which damage the ecosystem. This paper described some of the ARD-preventing technologies that are under investigation. In particular, it examined the feasibility of using Atikokan coal fly ash (AFA) as a buffering material to control and mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. Coal fly ash is the residue resulting from the combustion of coal at electric generating plants. It consists of organic and inorganic matter, including silica, alumina, iron and calcium oxide with various amounts of carbon. More than 40,000 tons of fly ash is generated each year from the Atikokan Generating Station located 190 km west of the mine, of which 80 per cent is used for concrete manufacturing. In this study, experiments were conducted to determine the physical, chemical and mineralogical properties of both the fly ash residue and mine tailings. Six kinetic column permeation tests were then performed to monitor the leaching properties of the fly ash and the coal fly ash-mine tailings mixtures to determine the hydraulic conductivities resulting from pozzolanic reactions. The potential impacts of the disposal of AFA and mine tailings were also assessed. The study showed that the hydraulic conductivities of high-calcium AFA and the ash-tailings mixtures were greatly reduced upon contact with ARD. The pH of the pore fluid increased from acidic to alkaline. The concentration of regulated elements in the leachate from the ash-tailings mixtures were also below the limits set by the Ontario Ministry of Environment. The results indicate that AFA could mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. 1 ref., 6 tabs., 10 figs., 1 appendix.

2006-01-01

184

Utilization of Atikokan coal fly ash in acid rock drainage control from Musselwhite Mine tailings  

Energy Technology Data Exchange (ETDEWEB)

Acid rock drainage (ARD) is the greatest environmental liability facing the mining industry. Mines produce acidic effluents that are generated from the chemical reaction of sulphide containing minerals and atmospheric oxygen. The effluents have a pH value as low as 2 to 4 and their movement is accompanied by heavy metals which damage the ecosystem. This paper described some of the ARD-preventing technologies that are under investigation. In particular, it examined the feasibility of using Atikokan coal fly ash (AFA) as a buffering material to control and mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. Coal fly ash is the residue resulting from the combustion of coal at electric generating plants. It consists of organic and inorganic matter, including silica, alumina, iron and calcium oxide with various amounts of carbon. More than 40,000 tons of fly ash is generated each year from the Atikokan Generating Station located 190 km west of the mine, of which 80 per cent is used for concrete manufacturing. In this study, experiments were conducted to determine the physical, chemical and mineralogical properties of both the fly ash residue and mine tailings. Six kinetic column permeation tests were then performed to monitor the leaching properties of the fly ash and the coal fly ash-mine tailings mixtures to determine the hydraulic conductivities resulting from pozzolanic reactions. The potential impacts of the disposal of AFA and mine tailings were also assessed. The study showed that the hydraulic conductivities of high-calcium AFA and the ash-tailings mixtures were greatly reduced upon contact with ARD. The pH of the pore fluid increased from acidic to alkaline. The concentration of regulated elements in the leachate from the ash-tailings mixtures were also below the limits set by the Ontario Ministry of Environment. The results indicate that AFA could mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. 1 ref., 6 tabs., 10 figs., 1 appendix.

Wang, H.L.; Shang, J.Q. [Western Ontario Univ., London, ON (Canada). Dept. of Civil and Environmental Engineering; Kovac, V. [Ontario Power Generation Inc., Toronto, ON (Canada). By-products, Fuel Division; Ho, K.S. [Trow Consulting Engineers, Brampton, ON (Canada)

2006-03-15

185

Comparative analysis of methods for determination of arsenic in coal and coal ash  

Energy Technology Data Exchange (ETDEWEB)

In this paper the comparative analysis of different methods for the preparation and analysis of arsenic content in coal and coal ash have been presented. The suggested method is coal digestion method, i.e., coal ash digestion using the mixture of acids: nitric and sulphuric in presence of vanadium-pentoxide as catalyzer. The comparative analysis of different recording techniques (AAS-GH, AAS-GF and ICP-AES) has also been presented. For arsenic recording the suggested technique is AAS-GF technique. The obtained results show that the method of high precision, high sensitivity and high reproductivity has been obtained.

Vukasinovic-Pesic, V.L.; Blagojevic, N.Z.; Rajakovic, L.V. [University of Montenegro, Podgorica (Montenegro)

2009-07-01

186

Sulfur removal from lignite using alkaline solution from tea waste ash by water extraction  

Energy Technology Data Exchange (ETDEWEB)

Some high-sulfur lignites were extracted with aqueous alkaline solution obtained from the water-soluble fraction of tea waste ash. High-sulfur removal from lignites was possible by this method. The effects of temperature, the amount of tea waste ash used, extraction time, and stirring speed were studied in the ranges 5-35 g, 350-550 K, 0.042-1.7 MPa, 15-60 min, and 300-600 rev/min, respectively. The extents of pyritic and organic sulfur removal were investigated. (Author)

Demirbas, A.

2000-10-01

187

Thermal expansion of slag and fly ash from coal gasification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Integrated gasification in combined cycle (IGCC) is an electrical power generation system, which is characterized to be a clean coal technology different than conventional process in combustible treatment. IGCC process gives rise to inorganic solid wastes in the form of vitreous slag and fly ashes w...

Aineto, Mónica; Acosta, Anselmo; Rincón, Jesús Ma.; Romero, Maximina

188

Using high energy gamma sources for coal ash content control  

International Nuclear Information System (INIS)

[en] The method is based on two effects, viz. multiple diffraction of ?-quanta from a Cs137 source and their subsequent absorption due to a photoeffect. Investigation results are given on the choice of optimum geometry of measurements and spectrum energy region with regard to coal ash content

1976-01-01

189

NOx reduction on coal chars doped with petroleum ashes  

Energy Technology Data Exchange (ETDEWEB)

Discusses the feasibility of using coal chars and the metals contained in ashes obtained from petroleum coke to produce catalyst doped activated carbons to be tested as reducing agents for NOx emissions. Transition metals were effective and they act as reductants and catalyst supports. 6 refs., 2 figs., 1 tab.

Moliner, R.; Lazaro, M.J.; Suelves, I.; Braekman-Danheux, C.; Vassilev, S. [Instituto de Carboquimica, Zaragoza (Spain)

1999-07-01

190

Coal ash usage in environmental restoration at the Hanford Site  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the use of coal ash from Hanford Nuclear Reservation steam plants as codisposal waste rock, landfill, or tank stabilization material; usage as a fuel source for energy recovery, as pipe or foundation backfill, or as an ornamental brick additive; and as aquarium rock, jewelry, or oyster bed stabilization material. Reducing the amount of waste produced is also discussed.

Scanlon, P.L.; Sonnichsen, J.C.; Phillips, S.J. [Westinghouse Hanford Co., Richland, WA (United States)

1995-09-01

191

Fast measurement of ash content in coal washing plant  

International Nuclear Information System (INIS)

[en] The coal filter cake is a product of fine coal after floatation which has an ash content of 7-13%, water content of 30+-2%, and a particle size of less than 1 mm. The ash content was measured by the intensity of the single backscattered gamma-ray, and its accuracy is mainly dependent on the energy of the gamma-ray. The 238Pu low energy photon source is selected in this work. The energy of its gamma-ray is 15 keV, which can result not only in the best sensitivity, but also in the lowest contribution to the environment radiation. The root mean square deviation of the ash measurement is +- 0.33% (+- 1 ?)

1993-01-01

192

Radiometric determination of ash content in brown coal  

International Nuclear Information System (INIS)

The possibilities of ash content determination in brown coal from the ''Turow'' strip mine, using a portable radioisotope X-ray fluorescence analyser have been investigated. Negative results were obtained when the characteristic radiation of iron was measured. Therefore, in further investigations the scattering of X-rays from 238Pu-source was applied. In this case a vanadium filter was used to eliminate fluorescent radiation of iron. The measurements were carried out on 30 coal samples of variable moisture, containing 13-45 per cent of ash. The experiments have shown that, with measurement times of about 1 min. the absolute standard error of ash content determination is about 2 per cent. (author)

1975-01-01

193

Conversion of different ash content brown coal in fluidized bed  

Energy Technology Data Exchange (ETDEWEB)

Available equations used to determine combustion specific rate of coal-derived cokes describe the burning of carbon particles well enough but are not accurate in case of ash-containing coke particles combustion. This study is an attempt to account for the influence of both initial ash content and its increase in the course of carbon conversion in specific rate calculations. The results of experimental study of burn-out dynamics of Volchanskiy field (North Urals) brown coal and its coke with different ash content under conditions of fluidized bed combustion at impulse-type non-gradient reactor RSC-1 and dynamic installation Pyrolysis-M are summarized. Diffusion and heterogeneous (kinetic) components of carbon combustion rate are identified separately by using diffusion and kinetics equation with correction for carbon mass fraction in particles. Burning particle overheating values and heterogeneous combustion rate constants at different temperatures are estimated.

Osipov, P.; Chernyavskiy, N.; Ryzhkov, A.; Remenuk, A. [Ural Federal Univ., Ekaterinburg (Russian Federation). Dept. of Thermal Power Plants; Dulienko, S. [National Academy of Science of Ukraine, Kiev (Ukraine). Coal Energy Technology Inst.

2013-07-01

194

Chemical, mineralogical and morphological changes in weathered coal fly ash: A case study of a brine impacted wet ash dump.  

Science.gov (United States)

The mobility of species in coal fly ash (FA), co-disposed with brine using a wet ash handling system, from a coal fired power generating utility has been investigated. The study was conducted in order to establish if the wet ash dump could act as a salt sink. The ash was dumped as a slurry with 5:1 brine/ash ratio and the dam was in operation for 20 years. Weathered FA samples were collected along three cores at a South African power station's wet ash dump by drilling and sampling the ash at 1.5 m depth intervals. A fresh FA sample was collected from the hoppers in the ash collection system at the power station. Characterization of both fresh FA and weathered FA obtained from the drilled cores S1, S2 and S3 was done using X-ray diffraction (XRD) for mineralogy, X-ray fluorescence (XRF) for chemical composition and scanning electron microscopy (SEM) for morphology. Analysis of extracted pore water and moisture content determination of the fresh FA and the weathered FA obtained from the drilled cores S1, S2 and S3 was done in order to evaluate the physico-chemical properties of the FA. The XRD analysis revealed changes in mineralogy along cores S1, S2 and S3 in comparison with the fresh FA. The SEM analysis revealed spherical particles with smooth outer surfaces for the fresh FA while the weathered ash samples obtained from cores S1, S2 and S3 consisted of agglomerated, irregular particles appearing to be encrusted, etched and corroded showing that weathering and leaching had occurred in the ash dump. The moisture content (MC) analysis carried out on the fresh FA (1.8%) and the weathered FA obtained from the drilled cores S1 (41.4-73.2%), S2 (30.3-94%) and S3 (21.7-76.2%)indicated that the ash dump was water logged hence creating favourable conditions for leaching of species. The fresh fly ash (n = 3) had a pH of 12.38 ± 0.15, EC value of 4.98 ± 0.03 mS/cm and TDS value of 2.68 ± 0.03 g/L, the pH of the drilled core S1 (n = 45) was 10.04 ± 0.50, the EC value was 1.08 ± 0.14 mS/cm and the TDS value was 0.64 ± 0.08 g/L. Core S2 (n = 105) had pH of 10.04 ± 0.23; EC was 1.08 ± 0.06 mS/cm and TDS was 0.64 ± 0.04 g/L, while core S3 (n = 66) had pH of 11.04 ± 0.09; EC was 0.99 ± 0.03 mS/cm and TDS was 0.57 ± 0.01 g/L. The changes in pH values can be attributed to the dissolution and flushing out of alkaline oxides like CaO and MgO from the dumped ash. The variations in pH values shows that the fly ash is acidifying over time and metal mobility can be expected under these conditions. The large decrease of EC in the drilled ash cores S1, S2 and S3 compared to the fresh ash indicated a major loss of ionic species over time in the ash dump. The XRF analysis showed the progressive dissolution of the major aluminosilicate ash matrix which influenced the release of minor and trace elements into the pore water enhancing their mobility as the ash dam acidified over time. Brine co-disposal on the ash may have been responsible for the slight enrichment of some species such as Na (0.27-0.56%), SO4(2-) (0.06-0.08%), Mg (0.57-0.96 %) and K (0.02-0.34%) in the disposed weathered FA. However, there was no significant accumulation of these species in the disposed FA despite continuous addition of large volumes of highly saline brine over the 20 year period that the dump existed, indicating that the ash dam was incapable of holding salts and continually released elements to the environment over the lifetime of the dam. PMID:24013557

Eze, Chuks P; Nyale, Sammy M; Akinyeye, Richard O; Gitari, Wilson M; Akinyemi, Segun A; Fatoba, Olanrewaju O; Petrik, Leslie F

2013-09-06

195

Chemical, mineralogical and morphological changes in weathered coal fly ash: A case study of a brine impacted wet ash dump.  

UK PubMed Central (United Kingdom)

The mobility of species in coal fly ash (FA), co-disposed with brine using a wet ash handling system, from a coal fired power generating utility has been investigated. The study was conducted in order to establish if the wet ash dump could act as a salt sink. The ash was dumped as a slurry with 5:1 brine/ash ratio and the dam was in operation for 20 years. Weathered FA samples were collected along three cores at a South African power station's wet ash dump by drilling and sampling the ash at 1.5 m depth intervals. A fresh FA sample was collected from the hoppers in the ash collection system at the power station. Characterization of both fresh FA and weathered FA obtained from the drilled cores S1, S2 and S3 was done using X-ray diffraction (XRD) for mineralogy, X-ray fluorescence (XRF) for chemical composition and scanning electron microscopy (SEM) for morphology. Analysis of extracted pore water and moisture content determination of the fresh FA and the weathered FA obtained from the drilled cores S1, S2 and S3 was done in order to evaluate the physico-chemical properties of the FA. The XRD analysis revealed changes in mineralogy along cores S1, S2 and S3 in comparison with the fresh FA. The SEM analysis revealed spherical particles with smooth outer surfaces for the fresh FA while the weathered ash samples obtained from cores S1, S2 and S3 consisted of agglomerated, irregular particles appearing to be encrusted, etched and corroded showing that weathering and leaching had occurred in the ash dump. The moisture content (MC) analysis carried out on the fresh FA (1.8%) and the weathered FA obtained from the drilled cores S1 (41.4-73.2%), S2 (30.3-94%) and S3 (21.7-76.2%)indicated that the ash dump was water logged hence creating favourable conditions for leaching of species. The fresh fly ash (n = 3) had a pH of 12.38 ± 0.15, EC value of 4.98 ± 0.03 mS/cm and TDS value of 2.68 ± 0.03 g/L, the pH of the drilled core S1 (n = 45) was 10.04 ± 0.50, the EC value was 1.08 ± 0.14 mS/cm and the TDS value was 0.64 ± 0.08 g/L. Core S2 (n = 105) had pH of 10.04 ± 0.23; EC was 1.08 ± 0.06 mS/cm and TDS was 0.64 ± 0.04 g/L, while core S3 (n = 66) had pH of 11.04 ± 0.09; EC was 0.99 ± 0.03 mS/cm and TDS was 0.57 ± 0.01 g/L. The changes in pH values can be attributed to the dissolution and flushing out of alkaline oxides like CaO and MgO from the dumped ash. The variations in pH values shows that the fly ash is acidifying over time and metal mobility can be expected under these conditions. The large decrease of EC in the drilled ash cores S1, S2 and S3 compared to the fresh ash indicated a major loss of ionic species over time in the ash dump. The XRF analysis showed the progressive dissolution of the major aluminosilicate ash matrix which influenced the release of minor and trace elements into the pore water enhancing their mobility as the ash dam acidified over time. Brine co-disposal on the ash may have been responsible for the slight enrichment of some species such as Na (0.27-0.56%), SO4(2-) (0.06-0.08%), Mg (0.57-0.96 %) and K (0.02-0.34%) in the disposed weathered FA. However, there was no significant accumulation of these species in the disposed FA despite continuous addition of large volumes of highly saline brine over the 20 year period that the dump existed, indicating that the ash dam was incapable of holding salts and continually released elements to the environment over the lifetime of the dam.

Eze CP; Nyale SM; Akinyeye RO; Gitari WM; Akinyemi SA; Fatoba OO; Petrik LF

2013-09-01

196

Retention of sulfur in fly ash from coal-fired boilers  

Energy Technology Data Exchange (ETDEWEB)

Sulphur retention depends on the alkaline metal oxide content of the fly ash. Correlations between retention and the relative concentrations of specific alkaline metal oxides are closer for boilers with similar combustion characteristics and particulate collection systems.

Davis, W.T.; Fiedler, M.A.

1982-04-01

197

Fundamental tests on recovery of valuable matters from coal ash  

Energy Technology Data Exchange (ETDEWEB)

Research results in 1986 were reported on the development project to recover the valuables in coal ash promoted since 1984. As for physical treatment, the fundamental data such as the recovery of fly ash magnetite (FAM) was gathered, and a wet roughing-wet cleaning benchmark equipment was tested. As for a direct acid leaching (DAL) process as chemical treatment, the solubility of fly ash was examined using the mixture of hydrochloric acid and hydrofluoric acid as solvent possible to solve mullite to enhance the extraction of Al, and the separation of Al, Fe and Ti elements in solution was basically tested by a solvent extraction method. While to improve the lower Al extraction of the DAL process, fly ash characteristics and the effects of CaO additives and sintering conditions on sintered products in a calsinter process were examined, and the solvent extraction of valuables from the sintered products was tested using sulfuric acid. 14 refs., 76., 15 tabs.

Murakami, Toru; Kumamoto, Junji; Sasaki, Yutaka (The Coal Mining Research Centre, Japan, Tokyo, Japan; Kobe Steel, Ltd., Tokyo (Japan); Onoda Cement Co., Ltd., Yamaguchi (Japan))

1987-08-01

198

Environmental performance assessment of coal ash use sites: Waukegan ash embankment  

Energy Technology Data Exchange (ETDEWEB)

A highway embankment site in Waukegan, Illinois, was investigated to measure the environmental effects of coal-ash use in highways and roads. Site construction in 1972--73 used about 375,000 metric tons of principally Type F fly ash. The site is a low-lying area a few hundred meters west of Lake Michigan. Field investigations were conducted at the site during 1987--1990. Samples of soil, groundwater, and vegetation were collected and analyzed for selected inorganic constituents. The field effort involved installing of 32 groundwater monitoring wells in the shallow groundwater aquifer, 13 lysimeters in unsaturated zone ash and soils, five trenches or boreholes to collect samples of ash and soils, and five points for vegetation sampling. Five separate sampling efforts were conducted. 27 refs., 32 figs., 19 tabs.

Rehage, J.A.; Holcombe, L.J. (Radian Corp., Austin, TX (USA))

1990-12-01

199

The occurrence of quartz in coal fly ash particles  

Energy Technology Data Exchange (ETDEWEB)

Quartz is present in both coal and residual ash. Ash originates from combustion of pulverised coal and, once removed from the flue gases by electrostatic precipitators (ESPs), it is called pulverized fuel ash (PFA). Thus, occupational exposure to PFA could also include exposure to silica. However, epidemiological studies did not show evidence of progressive massive fibrosis (PMF). In vitro tests demonstrated that PFA is less toxic than silica, and in vivo data of PFA did not support the importance of silica content for toxicity. Commissioned by the Dutch coal-fired power plants, KEMA has started a research project to determine the quartz content in coal and the corresponding PFA. It appears that on average 50% of the alpha-quartz in coal is found again in the total fraction of PFA (D50(ae) 31 {mu}m, where D50(ae) is the aerodynamically mass median diameter), whereas 16% is found in an even finer fraction (D50(ae) 10 {mu}m). The remaining part of the quartz is embedded in a glass phase. Scanning electron microscopy (SEM) with x-ray microanalyses (XMA) of cross-sections of 11,130 ash particles showed that quartz in PFAis present as unmelted sand particles. These quartz particles are angularly shaped. However, two types are to be distinguished: free coarse angular quartz particles (not respirable) and small angular quartz particles within the PFA particles. From the SEM/XMA results, it has to be concluded that the quartz in the respirable fraction is predominantly present within the original molten PFA particle. Since the effects of quartz are surface related, this elucidates the negative results of quartz-related effects of PFA in epidemiological, in vitro and in vivo studies. Besides, the amount of the total alpha-quartz in the respirable fraction of the ashes studied is less than 0.2%, so probably the Dutch occupational quartz standard of 0.075 mg m{sup 3} will not be exceeded.

Meij R.; Nagengast S.; Winkel H.T.

2000-10-15

200

Coal and coke - analysis and testing. Higher rank coal and coke - phosphorus - ash digestion/molybdenum blue method  

Energy Technology Data Exchange (ETDEWEB)

This Standard sets out a method for the determination of phosphorus in higher rank coal and coke or in the ash of these materials, as molybdenum blue, by spectrophotometry. This method is applicable also to the determination of phosphorus as phosphorus pentoxide in coal ash and coke ash.

NONE

2000-01-20

 
 
 
 
201

The use of coal fly ash for soil stabilization  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work was to examine the potential use of Wyoming subbituminous coal fly ash materials for cementation of soil materials. Specimens made from Laramie River (LR) fly ash had higher unconfined compression strength and more brittleness than the Specimens made with Dave Johnston (DJ) fly ash. However, soil/DJ fly ash mixtures that were cured for 28 days had relatively good strengths without the brittleness that the LR specimens developed. These characteristics of the DJ fly ash may be important attributes for road stabilization applications. The detailed mineralogical evaluation provides some insight into which minerals may enhance development of strength in these materials. In general, selective dissolution of the soil/fly ash mixtures shows that many of the potentially toxic elements (e.g., B, Cr, Fe, Mn, Ni, Pb) are associated with the sulfide phase (HNO{sub 3} extractable) and with the residual material. In this study, the dynamics of elemental release from the element pools did not result in toxic conditions. The formation of colloidal material capable of mobilizing potentially toxic elements was not found in the soil/fly ash mixtures. Apparently, the high pH of the materials enhanced immobilization of the high molecular weight material.

Brown, T.H.; Brown, M.A.; Sorini, S.S.; Huntington, G.

1991-12-01

202

Strongly alkaline pH avoidance mediated by ASH sensory neurons in C. elegans.  

UK PubMed Central (United Kingdom)

High pH is a noxious stimulus to animals, and their ability to avoid dangerously alkaline pH is critical for survival. However, the means by which they sense high pH has not been determined. The nematode Caenorhabditis elegans (C. elegans) avoids environmental pH above 10.5. In contrast, C. elegans mutants with structurally, developmentally, and/or functionally abnormal sensory cilia fail to avoid high pH, suggesting that sensory neurons in the cilia participate in sensing. Genetic rescue of the mutants indicates that ASH polymodal sensory neurons play a vital role in the process. Consistently, specific laser ablation of ASH neurons made animals insensitive to high pH. Furthermore, avoidance assays of other mutants also indicated that transient receptor potential vanilloid type (TRPV) ion channels encoded by osm-9 and ocr-2 are involved in sensing. Indeed, genetic rescue of osm-9 mutants by specifically expressing OSM-9 in ASH showed that TRPV channels play an essential role in sensing of high pH. Ca(2+) imaging in vivo also revealed that ASH neurons were activated by high pH stimulation, but ASH of osm-9 or ocr-2 mutants were not. These results demonstrate that in C. elegans, high pH is sensed by ASH nociceptors through opening of OSM-9/OCR-2 TRPV channels.

Sassa T; Murayama T; Maruyama IN

2013-06-01

203

Coal-fired gas turbine and ash separation system  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the application of a coal-fired gas turbine for combined-cycle power generation. A cycle with staged coal treatment, a counterflow combustor and an aerodynamic ash separation cyclone is chosen and its principal components are investigated. Conditions for self-stabilizing char (solid product of coal gasification) combustion are found experimentally and by mineral simulation. It is shown that the obstacle of sticking ash can be obviated by staged combustion of the char and products of mild coal gasification. Experiments carried out with a coal-fired gas turbine at the Technion Combustion Laboratory are described. The main component making it feasible and reliable is an ash separation device, whose performance is analysed experimentally and computationally. Results indicate that the device suffices for the creation of a dynamically stable protective layer on the turbine blades. Efficiency studies indicate good performance of a metal multicyclone with swirl motion of the aerosol initiated by air jets. Simulation of the two-phase flow within the device, explaining its performance, is discussed. 13 refs., 12 figs.

Povitsky, A.; Goldman, Y. [Technion-Israel Institute of Technology, Haifa (Israel). Faculty of Aerospace Engineering

1996-04-01

204

Clay formation and metal fixation during weathering of coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The enormous and worldwide production of coal fly ash cannot be durably isolated from the weathering cycle, and the weathering characteristics of fly ash must be known to understand the long-term environmental impact. The authors studied the weathering of two coal fly ashes and compared them with published data from weathered volcanic ash, it's closest natural analogue. Both types of ash contain abundant aluminosilicate glass, which alters to noncrystalline clay. However, this study reveals that the kinetics of coal fly ash weathering are more rapid than those of volcanic ash because the higher pH of fresh coal fly ash promotes rapid dissolution of the glass. After about 10 years of weathering, the noncrystalline clay content of coal fly ash is higher than that of 250-year-old volcanic ash. The observed rapid clay formation together with heavy metal fixation imply that the long-term environmental impact of coal fly ash disposal may be less severe and the benefits more pronounced than predicted from previous studies on unweathered ash. Their findings suggest that isolating coal fly ash from the weathering cycle may be counterproductive because, in the long-term under conditions of free drainage, fly ash is converted into fertile soil capable of supporting agriculture.

Zevenbergen, C.; Bradley, J.P.; Reeuwijk, L.P. Van; Shyam, A.K.; Hjelmar, O.; Comans, R.N.J.

1999-10-01

205

Clay formation and metal fixation during weathering of coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The enormous and worldwide production of coal fly ash cannot be durably isolated from the weathering cycle, and the weathering characteristics of fly ash must be known to understand the long-term environmental impact. Weathering of two coal fly ashes was compared with published data from weathered volcanic ash, its closest natural analogue. Both types of ash contain abundant aluminosilicate glass, which alters to noncrystalline clay. However, this study reveals that the kinetics of coal fly ash weathering are more rapid than those of volcanic ash because the higher pH of fresh coal fly ash promotes rapid dissolution of the glass. After about 10 years of weathering, the noncrystalline clay content of coal fly ash is higher than that of 250-years old volcanic ash. The observed rapid clay formation together with heavy metal fixation imply that the long-term environmental impact of coal fly ash disposal may be less severe and the benefits more pronounced than predicted from previous studies on unweathered ash. Findings suggest that isolating coal fly ash from the weathering cycle may be counterproductive because in the long-term under conditions of free drainage, fly ash is converted into fertile soil capable of supporting agriculture. 28 refs., 4 figs., 2 tabs.

Zevenbergen C.; Bradley, J.P.; Van Reeuwijk, L.P.; Shyam, A.K.; Hjelmar, O.; Comans, R.N.J. [IMWACO B.V., Rotterdam (Netherlands)

1999-10-01

206

Statistical analysis of automated coal-ash fusion temperatures for West Virginia coals  

Energy Technology Data Exchange (ETDEWEB)

During 1984-1986, the West Virginia Geological and Economic Survey dramatically expanded its coal-ash fusion data base, and conducted statistical studies of the new data. More, better distributed data were obtained for the Survey's computerized data base, which is used in (1) the coal-quality exploration program, (2) mapping, and (3) estimating ash fusion temperature based on ash and sulfur in coal. The new data, obtained using an automated ash fusion analyzer, were subjected to extensive analysis. Along with realizing the major goals of the study, they have three additional findings. (1) Interpolating between reducing-atmosphere softening temperature and reducing-atmosphere fluid temperature has yielded a reliable equation to predict the reducing-atmosphere hemispherical temperature of West Virginia coals. This parameter is missing from many older analyses. (2) Regardless of the care taken, human factors figure heavily in the accuracy of all ash fusion tests performed in nonautomated ash fusion analyses. (3) They have developed improved estimation equations using machine-generated ash fusion analyses that will be more reliable than earlier equations that used a combination of human operator and machine analyses.

McColloch, G.H. Jr.; Ashton, K.C.; Smith, C.J.; Hohn, M.E.

1987-09-01

207

Use of brown coal ashes from Rhenish briquetting coals as mineral lime fertilizers  

Energy Technology Data Exchange (ETDEWEB)

As early as in the fifties fly ash of the RWE Grosskraftwerk Fortuna was utilized as lime fertilizer and mortar binder. In the mine power plants of Rheinbraun AG in the rhenish lignite district low-ash briquetting coal is fired which results in a more even fly ash quality. These ashes are utilized as a mineral lime fertilizer and due to their calcium and magnesium content they are able to nourish the plant. They are suitable for recovery and conservation fertilizing. 5 figs., 3 tabs.

Moehlenbruch, N.; Faber, W.; Paeffgen, H.-P. (Rheinbraun AG, Frechen (Germany). Sibylla Research Centre)

1992-08-01

208

Microwave-assisted sample preparation of coal and coal fly ash for subsequent metal determination  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to review microwave-assisted digestion of coal and coal fly ash. A brief description of microwave heating principles is presented. Microwave-assisted digestion appears currently to be the most popular preparation technique, possibly due to the comparatively rapid sample preparation and the reduction of contamination, compared to the conventional hot-plate digestion methods.

Srogi, K. [Inst. of Chemical Processing of Coal, Zabrze (Poland)

2007-01-15

209

Coal ash parameters by natural radioactivity and neutron activation  

International Nuclear Information System (INIS)

Natural radioactivity of 400 coal and sedimentary rock samples, collected from cores of the wells drilled in the Upper Silesia Coal Basin, has been measured in order to determine the uranium, thorium and potassium concentrations with the use of a scintillation gamma-ray spectrometric system. The determined concentrations were used to identify the lithology of the rocks and evaluate the following hard coal parameters: ash content, calorific value and carbon content. The mean standard deviation of 1.3 wt% for the ash content between 2-35 wt%, 1.3 MJ/kg for the calorific value between 17-32 MJ/kg and 2.5 wt% for the carbon content between 43-72 wt% were obtained. Feasibility of determination of the ash content and the ash fusion temperature via the neutron activation technique has been examined, both in the laboratory and field conditions. The technique is based on recording induced gamma- ray intensities in two energy intervals with the help of a scintillating gamma ray spectrometer. In laboratory and in well logging, the mean standard deviations were 1.5 wt% and 35 deg. C, and 3 wt% and 45 deg. C, respectively. (author). 11 refs, 6 figs, 5 tabs.

1995-01-01

210

Experimental determination of the equivalent thermal diffusivity for porous coal-ash particles  

Energy Technology Data Exchange (ETDEWEB)

The equivalent thermal diffusivity of spherical porous coal-ash particles has been determined by measuring the temperature response curve both in the center and on the surface. In this paper a general relationship between the equivalent thermal diffusivity of the porous coal-ash particles and the ash content within the coal is obtained. Based on this relationship, prediction of the burning rate of a large coal char particle becomes possible.

Fu, W.B.; Zhang, B.L.; Zheng, S.M. (Tsinghua Univ., Beijing, BJ (China))

1992-12-01

211

Measurement of the ash content of coal  

International Nuclear Information System (INIS)

An apparatus suitable for determining the noncombustible content of coal in railroad cars or other transportation containers consists of a neutron source, a detector of gamma rays of a predetermined energy characteristic of aluminum 28 and a readout device.

1978-10-02

212

Structural and hydrological alterations of soil due to addition of coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Purpose: We tested the potential of using coal fly ash for improving the physical and hydrological characteristics of coarse and medium-textured agricultural soils. Materials and methods: Acidic (FWA) and alkaline (FNSW) fly ashes were used to amend a range of representative agricultural soils. In the first experiment, fly ash was applied to the top 10 cm of 1-m long intact cores of a sandy loam soil at rates of 0, 12, 36 or 108 Mg/ha and sown with canola; after harvest, bulk density (BD), aggregate stability and mean weight diameter (MWD) were measured on the soil. In the second experiment, we assessed water retention at field capacity (-300 kPa) and permanent wilting point (-1,500 kPa) for sandy and loamy soils amended with FNSW at 0.0-16% (w/w). The third experiment used rainfall simulation to assess erodibility of sandy and loamy soils mixed with FNSW at rates of 0, 5 or 20 Mg/ha. Results and discussion: In the first experiment, fly ash had no significant effect on MWD of the soil. The BD in the 0-10 cm layer (topsoil) was increased with addition of FWA, while FNSW applied at 108 Mg/ha reduced BD, relative to the control treatment. This was because FNSW had lower particle and bulk densities than FWA and the test soils. Ash addition increased macro-aggregation, significantly so in the 10-20 cm layer (subsurface layer), by reducing the percentages of micro-aggregates and silt + clay particles. Thus, macro-aggregation was positively correlated (p < 0.01) with MWD, but both were inversely correlated (p < 0.01) with micro-aggregates. In the second experiment, addition of fly ash enhanced plant water availability by increasing water retention at field capacity by threefold in the sandy soil and 1.5-fold in the loamy sand, but water retention at permanent wilting point was not affected. In Experiment 3, the addition of ash at 20 Mg/ha, but not at 5 Mg/ha, increased turbidity of runoff water from the amended soil due to the dispersal of fine particles by the impact of the simulated raindrops. Conclusions: Moderate rates of fly ash (< 12 Mg/ha or {<=} 2% w/w) addition can improve aggregation and plant water availability in light to medium-textured soils. Soil applications thus provide a significant end-use for fly ash and can be a part of strategies for minimising environmental footprints from coal-fired power generation. Future studies are needed to further optimise application practices for long-term sustainability. (orig.)

Yunusa, Isa A.M. [New England Univ., Armidale, NSW (Australia). School of Environmental and Rural Sciences; Manoharan, V.; Skilbeck, C. Greg; Eamus, Derek [University of Technology, Sydney, Broadway, NSW (Australia). Dept. of Environmental Science; Odeh, Inakwu O.A. [Sydney Univ., NSW (Australia). Faculty of Agriculture, Food and Natural Resources; Shrestha, Surendra [Western Sydney Univ., Penrith South DC, NSW (Australia). School of Engineering, College of Health and Science

2011-04-15

213

Performance testing with high ash Indian coals and coal washery rejects in an AFBC pilot plant  

Energy Technology Data Exchange (ETDEWEB)

Under a cooperative agreement between the US Agency for International Development (USAID) and the Government of India (GOI), a joint research project in fluidized bed combustion (FBC) is being carried out by the Bharat Heavy Electricals Ltd. (BHEL), India, and the Oak Ridge National Laboratory (ORNL). The project is aimed at obtaining basic engineering data on the combustion of high-ash Indian coals (up to 45% ash), coal washery rejects (up to 70% ash), and high-sulfur (up to 5%) US coals. Quantitative measurements of freeboard combustion, freeboard heat transfer, and freeboard gas composition are of particular interest. A FBC test facility has been erected at BHEL, Trichy. Tests have been conducted on a sub-bituminous Indian coal (38% ash) and a washery reject (65% ash) with and without flyash reinjection. The combustion efficiency was typically 95-98% for the coal and 85-90% for the rejects. Freeboard combustion was 6-9% for the coal and 3-6% for the rejects. 11 refs., 6 figs., 2 tabs.

Krishnan, R.P.; Anthony, J.; Rajavel, M.; Srinivasan, S.; Rao, A.J.; Rajaram, S.

1989-01-01

214

Characterization of coal fly ash by FTIR, XRD and SEM  

Energy Technology Data Exchange (ETDEWEB)

Different characterization techniques such as FTIR (Fourier transform infrared spectroscopy ), XRD (X-ray diffraction), and SEM (scanning electron microscopy) have been applied to analyze the different fractions of fly ash. FTIR studies show the presence of quartz, alumina, hematite, and different mineral matters whereas XRD confirms the presence of these minerals in different fractions of coal fly ash. The morphology has been studied by SEM and it is found that it consists largely of solid or hollow spherical particles of variable size with small bulges of siliceous and aluminous glass with the appearance of cracking at the tip of the bulges. 18 refs., 3 figs., 2 tabs.

Singh, B.K.; Rawat, N.S. [Government Autonomous MH College of Home Science and Science, Jabalpur (India)

1995-12-31

215

Rapid reliable determination of ash and total sulfur in coal  

International Nuclear Information System (INIS)

Radionuclide X-ray fluorescence analyzers manufactured by the PAR company are reliable portable instruments designed for rapid determination of ash and total sulfur in coal at mining facilities. Ash analyzers are manufactured in two basic versions: as autonomous instruments (RPM series) or as instruments to be interfaced to a PC (RPP series). The basic design features and performance parameters of the instruments are highlighted. State-of-the-art sulfurometers are equipped with Si/Li semiconductor detectors, exhibiting a very good spectral resolution. (P.A.).

1998-01-01

216

Radiometric determination of uranium leached biochemically from coal fly ashes  

International Nuclear Information System (INIS)

The method of radiometric determination of uranium leached by Thiobacillus ferrooxidans bacteria from fly ashes of hard and brown coals has been developed. The leached uranium was extracted from leaching medium by using toluene solution of tributylphosphate. To the organic phase containing extracted uranium the scintillation solution Permafluor 1 was added and solution activity was recorded using scintillation counter. The elaborated method enables to determine trace amounts of the leached uranium (?10-7 g/ml) in leaching solution containing bacterial culture Thiobacillus ferrooxidans and suspended ashes. (author).

1983-01-01

217

BIOAVAILABILITY OF 1-NITROPYRENE FROM MODEL COAL FLY ASH AND ITS UPTAKE BY ALVEOLAR MACROPHAGES  

Science.gov (United States)

Alveolar macrophage cultures exposed to coal fly ash vapor-coated with 1-nitropyrene were used as a model system to study the bioavailability and the uptake of a nitroaromatic hydrocarbon from coal combustion emissions. Initially, 1-nitropyrene-coated fly ash and uncoated fly ash...

218

Ash level meter for a fixed-bed coal gasifier  

Energy Technology Data Exchange (ETDEWEB)

An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by a appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500/sup 0/F), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage. 7 figures.

Fasching, G.E.

1982-10-12

219

Effect of coal ash disposal upon an unconfined alluvial system  

International Nuclear Information System (INIS)

Fly and bottom ash from coal combustion has been disposed in four ash ponds in an alluvial valley. Three of the ash ponds are receiving ash and one was filled and closed. Twenty eight monitoring wells ranging in depth from 10 feet to 65 feet have been installed at the site to study groundwater flow and chemistry. Hydraulic heads are influenced by the stage of the Kentucky River, and the flow direction is vertical below the ash ponds and predominantly horizontal a short distance from the pond all the way to the river. Three different groundwater flow zones were observed and have unique water chemistry. The deep zone (near bedrock) has a low Eh ( 100) and lower concentrations of Fe and ammonia nitrogen, median sulfate concentration (114 mg/l), and arsenic is below detection limits. The shallow groundwater zone is through the closed out ash point and has higher concentrations of nearly all cations and anions, including sulfate (888 mg/l) and arsenic (exists as arsenite) at concentration of 0.9 mg/l, low Eh (

1992-01-01

220

Adsorption of herbicides on coal fly ash from aqueous solutions.  

UK PubMed Central (United Kingdom)

Development of low cost adsorbent for pesticide retention is an important area of research in environmental sciences. The present study reports the sorption potential of coal fly ash, a waste from power stations, for removal of metribuzin, metolachlor and atrazine from water. Batch sorption method was used to study the sorption of herbicides from water. The amount of herbicides sorbed increased with increase in the amount of fly ash in the suspension. The maximum capacity of the fly ash to adsorb metribuzin, metolachlor and atrazine was found to be 0.20, 0.28 and 0.38 mg/g by Freundlich equation and 0.56, 1.0 and 3.33 mg/g by Langmuir equation. Freundlich adsorption equation better explained the results of herbicides sorption in fly ash as regression coefficient (R(2)) values were higher from Freundlich equation than the Langmuir equation. Adsorption isotherms were L-type suggesting that the herbicide sorption efficiency of fly ash depend on the initial concentration of herbicide in the solution and maximum removal of herbicide was observed at concentrations less than 10 microg/ml. The results of this study have implications in using the fly ash for removal of these herbicides from industrial and agricultural waste water and can find use as a material in the preparation of biobeds to minimize environmental contamination from pesticide use.

Singh N

2009-08-01

 
 
 
 
221

Ash fusion temperatures and their association with the transformations of coal ash particles to slag  

Energy Technology Data Exchange (ETDEWEB)

Ash deposition on furnace walls in PF (pulverized fuel) furnaces is called slagging when it occurs in the high temperature areas of furnaces directly exposed to flame radiation and fouling in other regions such as tubes in the convection section of the boiler. There are well documented shortcomings of certain approaches relating to their uncertainties as predictive tools for plant performance such as poor repeatability and re-producibility of ash fusion measurements. The nature of physical and chemical changes occurring during melting of coal ash has been investigated in the current study to provide an alternative procedure to the ash fusion test. Shrinkage measurements are frequently used in metallurgy and ceramic science to study the physical properties of materials at high temperatures. The output of this experiment provides three to four `peaks` (maximum rate of shrinkage with temperature) of different intensity and at different temperatures which are related to melting characteristics of the sample. It was concluded that shrinkage extents exceeding 50 percent indicated that the effect of the ash particle size is of secondary importance compared to ash chemistry in determining shrinkage levels, with fine particles giving rapid shrinkage events 10 degrees C lower in temperature. (author). 7 figs., refs.

Gupta, S.K.; Wall, T.F.; Gupta, R.P. [Cooperative Research Centre for Black Coal Utilisation, Newcastle, NSW (Australia); Creelman, R.A. [Creelman (R.A.) and Associates, Sydney, NSW (Australia)

1997-04-01

222

Coal face and stockpile ash analyser for the coal mining industry  

International Nuclear Information System (INIS)

[en] A portable nucleonic instrument was developed for the determination of coal ash on the coal face or the surface of coal stockpiles. The instrument employs the backscattered gamma-gamma technique. There are two ?-ray sources used in this instrument: a 1.1 MBq 133Ba source as the primary source of radiation and a 37 kBq 137Cs for gain stabilization. The instrument is commercially available

2001-01-01

223

Influence of mineral and chemical composition of coal ashes on their fusibility  

Energy Technology Data Exchange (ETDEWEB)

The relationships between ash-fusion temperature (AFT) and mineral and chemical composition of coals and coal ashes from a wide variety of deposits (41) were studied by a melting test, X-ray diffractometry, light microscopy, differential-thermal, thermogravimetric and chemical analyses. A reliable explanation and prediction of AFT only from the total chemical composition of coal ash is inadequate because most important are the modes of elemental combination (minerals and phases) in coal and coal ash, as well as their behaviour during heating. The coals, which have low-melting temperature ashes, are lower rank coals with increased concentrations of S, Ca, Mg, Fe and Na and respectively, sulphates, carbonates, sulphides, oxides, montmorillonite, and feldspars. The coals with high-melting temperature ashes have an advanced rank and increased contents of Si, Al and Ti and respectively, quartz, kaolinite, illite and rutile, as well as some Fe oxides and siderite. The behaviour of chemical components and various coal and coal-ash minerals during heating is discussed, and their refractory and fluxing influence on ash fusibility is described. Lower AFT is related to increased proportions of the fluxing sulphate, silicate and oxide minerals such as anhydrite, acid plagioclases, K feldspars, Ca silicates and hematite in high-temperature coal ashes. Higher AFT is a result of decreased fluxing minerals and increased refractory minerals such as quartz, metakaolinite, mullite, and rutile in these ashes. Defined softening, hemispherical and fluid ash-fusion temperatures fit various processes of inorganic transformations which are discussed. A reliable explanation and prediction of ash-fusion characteristics can be made when the coal and coal-ash minerals and their amounts, as well as their refractory and fluxing action during heating, are known. 31 refs., 7 figs., 5 tabs.

Vassilev, S.V.; Kitano, K.; Takeda, S.; Tsurue, T. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Institute of Applied Mineralogy

1995-10-01

224

JV Task 6 - Coal Ash Resources Research Consortium Research  

Energy Technology Data Exchange (ETDEWEB)

The Coal Ash Resources Research Consortium{reg_sign} (CARRC{reg_sign}, pronounced 'cars') focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of coal combustion by-products (CCBs). CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCB utilization and ensuring its successful application. The U.S. Department of Energy is a partner in CARRC through the EERC Jointly Sponsored Research Program (JSRP), which provides matching funds for industrial member contributions and facilitates an increased level of effort in CARRC. CARRC tasks were designed to provide information on CCB performance, including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC technical research tasks are developed based on member input and prioritization. CARRC special projects are developed with members and nonmembers to provide similar information and to support activities, including the assembly and interpretation of data, support for standards development and technology transfer, and facilitating product development and testing. CARRC activities from 1998 to 2007 included a range of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCBs. CARRC topical reports were prepared on several completed tasks. Specific CARRC 1998B2007 accomplishments included: (1) Development of several ASTM International Standard Guides for CCB utilization applications. (2) Organization and presentation of training courses for CCB professionals and teachers. (3) Development of online resources including the Coal Ash Resource Center, Ash from Biomass in Coal (ABC) of cocombustion ash characteristics, and the Buyer's Guide to Coal-Ash Containing Products. In addition, development of expanded information on the environmental performance of CCBs in utilization settings included the following: (1) Development of information on physical properties and engineering performance for concrete, soil-ash blends, and other products. (2) Training of students through participation in CARRC research projects. (3) Participation in a variety of local, national, and international technical meetings, symposia, and conferences by presenting and publishing CCB-related papers.

Debra Pflughoeft-Hassett; Tera Buckley; Bruce Dockter; Kurt Eylands; David Hassett; Loreal Heebink; Erick Zacher

2008-04-01

225

Determination of ASH content in coals by gamma reflection method  

International Nuclear Information System (INIS)

[en] The effective atomic number Z dependence of the ratio R of the intensity of elastically and inelastically scattered X-ray has been employed in the determination of the ASH contents of some coal samples from Hungary, Poland and Russia. The results obtained by this method compared favorably with those obtained by the combustion method. This fast, simple and nondestructive method can therefore be used for on-line quality control of coal produced in a mine. (author). 4 refs., 3 figs., 3 tabs

1996-01-01

226

Mineralogy and chemistry of conventional and fluidised bed coal ashes  

Directory of Open Access Journals (Sweden)

Full Text Available Coal combustion residues represent very abundant inorganic waste materials. The change from conventional combustion of powdered North Bohemian brown coal to its combustion in fluidised bed boilers in several Czech power and heating plants calls for detailed mineralogical and geochemical characterisation of the combustion residues. The main differences between fly ashes from both combustion systems result from different burning temperatures and differing systems of desulphurisation (coeval with combustion / post-combustion). Both these factors influence the chemical and phase compositions as well as the speciation of trace elements. The study further shows that the validity of the surface enrichment model (Linton et al. 1975) can be limited.

Sulovský P

2002-01-01

227

Determination of the ash content of coal using annihilation radiation  

International Nuclear Information System (INIS)

The ash content of coal can be determined by a simple technique based on the simultaneous measurement of 0.511 MeV annihilation radiation and Compton scattering radiation which result from irradiation of a coal sample with ? rays energy > 1.022 MeV. These measurements are performed using 60Co source and NaI(Tl) detector in a backscatter geometry. The advantages of this method are less sensitivity to high Z elements such as Fe and Ca, less sensitivity to moisture variation and potentially greater depth penetration because of the higher energies used

1998-01-01

228

Laboratory determination of the ash content of some Australian coals using radioisotope techniques  

International Nuclear Information System (INIS)

[en] Two radioisotope techniques suitable for the rapid laboratory determination of the ash content of coal have been tested on unwashed coal samples from four Australian coal seams. In one technique, measurements of backscattered 238Pu L X-rays and iron K X-rays from finely ground coal samples have been combined to determine ash content in unwashed coals to +- 0.5 weight per cent ash for three seams and +- 0.9 weight per cent ash for the fourth. The second technique, which involves measurements of the transmission by the coal of narrow beams of 241Am 60 keV and 133Ba 356 keV ?-rays, requires less sample preparation. The ash was determined to within the range of 0.8 to 2.6 weight per cent for the four seams (unwashed coal). For washed coals, errors are expected to be

1982-01-01

229

Microbial treatment of coals and its effect on ash fusion properties  

Energy Technology Data Exchange (ETDEWEB)

One objective of this study was to characterize the microbial demetalization and desulfurization of coal by the bacterium Thiobacillus ferrooxidans under aerobic conditions. The effects of type of coal, coal particle size, and nutrient concentration on the bacterial leaching of coal were investigated. Ash fusion temperatures of treated and untreated coal samples were measured and an attempt was made to relate variations to the coal and ash properties. Another objective was to determine the extent of dissolution of different metals from coal residues by the action of native autotrophic bacteria under aerobic conditions. The effects of inorganic nutrient supplements were also studied. It was concluded that microbial action on bituminous coals under aerobic conditions can lead to significant reductions in inorganic sulfur, metals and total ash content, as well as considerable increase of ash fusion temperatures of the remaining ash.

Krishna, C.R.; Francis, A.J.

1988-01-01

230

Dry bottom ash technology improves coal fired boiler operations  

Energy Technology Data Exchange (ETDEWEB)

In the Spanish coal fired power plant of Los Barrios, owned and operated by Endesa Generaion, an innovative dry technology has been retrofitted reducing strongly the operating and maintenance costs for the bottom ash and pyrites handling, and in the same time providing a reduction of the environmental impact of the plant. In particular, the use of water in bottom ash handling and the production of waste water has been eliminated completely, and the boiler's heat losses have been reduced, leading to a saving of coal consumption and a reduction of gaseous emissions including CO{sub 2}. Additional benefits of the project include a higher dependability of the system, preventing forced boiler outages, and a better saleability of the bottom ash. In this paper, an analysis of the performance of the power plant's previous wet bottom ash and pyrites handling is provided, leading to the reasons for replacing it by the dry system. Initial operating results of the new dry system are also presented to evaluate the improvements achieved. 5 refs., 3 figs., 2 tabs.

Carrieri, R.; Giraldez, J.A.H. [Magaldi Power S.p.A., Salerno (Italy)

2004-07-01

231

Groundwater impact studies at three Ontario Hydro coal ash landfills  

International Nuclear Information System (INIS)

Ontario Hydro has produced on the order of 21 million Mg of coal fly ash over the past 40 years, of which, 80% has gone to various landfill sites in the province of Ontario. Hydrogeologic investigations have been performed in the vicinity of three Ontario Hydro coal ash landfill sites to assess the environmental impact of fly ash landfilling on the local groundwater regime. Two of the waste management facilities are associated with thermal generating stations (Lambton TGS and Nanticoke TGS) and are founded on relatively impermeable clay deposits. The third site, Birchwood Park, is a former sand and gravel pit for which the landfill design did not incorporate the use of a liner material. The rates of groundwater flow through the overburden materials a the three sites vary from less than 1 cm/a at the Lambton TGS site, to between 3.45 cm/a and 115 cm/a at contaminant transport at these sites also varies from being controlled by molecular diffusion to advection. This paper discusses the migration rates of contaminants from fly ash leachate at each of the three sites with implications to landfill containment and design

1992-01-01

232

Environmental and health aspects of coal co-combustion ash  

Energy Technology Data Exchange (ETDEWEB)

Co-combustion is an important aspect of power generation from coal in the Netherlands and additional European countries. It is important that the environmental and occupational health aspects of fly ash are not negatively influenced by co-combustion activities. Since 1993 KEMA has studied the effect of direct co-combustion in more than fifty test series. In these test series secondary fuels were co-combusted in proportions up to 40 % by dry mass. (orig.)

Winkel, Henk te [KEMA Technical and Operational Services, Arnhem (Netherlands)

2010-07-01

233

Microcomputer technique in on-line measurement of coal ash content  

International Nuclear Information System (INIS)

[en] The on-line measurement of coal ash content is a key technique urgently needed in coal industry. In principle it can be realized using nuclear technology. But it's practice only when microcomputer is introduced. The paper describes the microcomputer technique used in the on-line coal ash content measurement by bi-energy ?-ray transmission method

1995-11-01

234

On-line analyzer of ash content in coal  

International Nuclear Information System (INIS)

[en] The radioisotope method for ash content measurement consists in effective atomic number (Z) determination. The considerable difference between Z of combustible and noncombustible coal phases is used. Due to changeable chemical composition and physical structure of the material, the radiations with two different energies are used and their attenuation and scattering is registered. In order to avoid the impact of the variable size and surface of the material on the transportation line, a wide-surface proportional detector is used. It registers the scattering of X-ray radiation (Pu-238 or Cd-109) from the coal surface of about 0.1 m2. The gamma radiation (Am-241) passing through the coal is registered by a scintillation probe. The developed ash-meter works with a bound torsion scales that continuously transmits signal of the instant load and the total material quantity. The measurement system is developed on the basis of a PC AT industrial type. All system elements, analytical software and the construction itself are Bulgarian made. The sensitivity, accuracy and measurement rate of the equipment are in no way inferior to the best foreign analogues and excel the ash-meters from former East Germany and Czechoslovakia. The analyzer is installed and at present is being tested in real production conditions at Maritza-East-2 Thermal Power Plant. (author)

1993-06-01

235

Adsorption of an acid dye onto coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

In this study, we found the raw coal fly ash (CFA) that had not been subjected to any pretreatment process had superior adsorbing ability for the anionic dye Acid Red 1 (AR1) than did two modified coal fly ashes (CFA-600 and CFA-NaOH). The adsorption capacities followed the order CFA > CFA-600 > CFA-NaOH, and they each increased upon increasing the temperature (60{sup o}C > 45{sup o}C > 30{sup o}C). The adsorptions of AR1 onto CFA, CFA-600, and CFA-NaOH all followed pseudo-second-order kinetics. The isotherms for the adsorption of AR1 onto the raw and modified coal fly ashes fit the Langmuir isotherm quite well; the adsorption capacities of CFA, CFA-600, and CFA-NaOH for AR1 were 92.59-103.09, 32.79-52.63, and 12.66-25.12 mg g{sup -1}, respectively. According to the positive values of {Delta}H{sup o} and {Delta}S{sup o}, these adsorptions were endothermic processes. The ARE and EABS error function methods provided the best parameters for the Langmuir isotherms and pseudo-second-order equations, respectively, in the AR1-CFA adsorption system. 36 refs., 6 figs., 5 tabs.

Ting-Chu Hsu [Vanung University, Chung-Li (Taiwan). Department of Environmental Engineering

2008-10-15

236

The future resources for eco-building materials: II. Fly ash and coal waste  

Energy Technology Data Exchange (ETDEWEB)

To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation, removal of carbon remains and fine comminution, calcining coal waste into kaolin and meta-kaolin with suspension technology, and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.

Hui Li; Delong Xu [Xi' an University of Architecture & Technology, Xi' an (China). China State key Laboratory of Western Architecture & Technology

2009-08-15

237

Determining ash content in power coal by spectrometry of scattered gamma radiation  

International Nuclear Information System (INIS)

[en] Spectrometers are described used for determining ash content in coal of a grain size up to 10 mm. The results obtained showed that spectrometers of scattered gamma radiation could be employed. The amount of ash in coal, this up to 45% of the ash content could be directly assessed from the pulse rate pertaining to the peak of the measured spectrum or from the measured spectra ratios. The accuracy of ash content de--termination was +-2%. (J.B.)

1981-01-01

238

Low-level radiation in coals utilized and ashes produced at New York State electric utilities  

International Nuclear Information System (INIS)

[en] Eight coal-fired power plants in New York State were sampled for coal, fly ash and bottom ash. Samples were analyzed for uranium 238, uranium 235, uranium 234, thorium 232, thorium 230, radium 226, lead 210, polonium 210, radon 222. The leachate of six fly ash samples was analyzed for all of the above except radon 222. Some data on fly ash analysis are included

1981-09-17

239

Evaluation and Treatment of Coal Fly Ash for Adsorption Application  

Directory of Open Access Journals (Sweden)

Full Text Available Many researchers had investigated fly ash as an adsorbent for the uptake of organic compounds from petrochemical waste effluents. The availability, inexpensive and its adsorption characteristic had made it an alternative media for the removal of organic compounds from aqueous solution. The physical property of South African Coal Fly Ash (SACFA) was investigated to determine its adsorption capability and how it can be improved. Chemical treatment using 1M HCl solution in the ratio of (1 g) fly ash to (2 ml) of acid was used and compared with untreated heat-treated samples. The chemically treated fly ash has a higher specific surface area of 5.4116 m2/g than the heat-treated fly ash with 2.9969 m2/g. More attention had to be given to the utilization of SACFA for the treatment of wastewaters containing organic compounds through the application of Liquid phase adsorption process that was considered as an inexpensive and environmentally friendly technology.

Samson Oluwaseyi BADA; Sanja POTGIETER-VERMAAK

2008-01-01

240

Water Retention Characteristics of Porous Ceramics Produced from Waste Diatomite and Coal Fly Ash  

Directory of Open Access Journals (Sweden)

Full Text Available This study examines potential waste diatomite and coal fly ash reuse to prepare water absorption and retain porous ceramics. The operating conditions are constant pressure (5 MPa), sintering temperature (1000-1270°C), sintering time (2 h), waste diatomite containing coal fly ash at different proportions (0-20%), respectively. The porous ceramic samples containing coal fly ash show low thermal conductivity properties (0.278-0.349 W/mK), probably owing to the more pores than those in the concrete (1.458 W/mK). Water release (t1/2 value) by the porous ceramic samples is decelerated by porous ceramic samples containing coal fly ash, due to the synergy effect of high water absorption by the coal fly ash and better than in the foamed glass material (4 h). Porous ceramic samples containing coal fly ash is highly promising for use in water absorption and retention applications.

Kae-Long Lin; Ju-Ying Lan

2013-01-01

 
 
 
 
241

Environmental impacts of the Tennessee Valley Authority Kingston coal ash spill. 2. Effect of coal ash on methylmercury in historically contaminated river sediments.  

UK PubMed Central (United Kingdom)

The Tennessee Valley Authority Kingston coal ash spill in December 2008 deposited approximately 4.1 million m(3) of fly ash and bottom ash into the Emory and Clinch River system (Harriman, Tennessee, U.S.A.). The objective of this study was to investigate the impact of the ash on surface water and sediment quality over an eighteen month period after the spill, with a specific focus on mercury and methylmercury in sediments. Our results indicated that surface water quality was not impaired with respect to total mercury concentrations. However, in the sediments of the Emory River near the coal ash spill, total mercury concentrations were 3- to 4-times greater than sediments several miles upstream of the ash spill. Similarly, methylmercury content in the Emory and Clinch River sediments near the ash spill were slightly elevated (up to a factor of 3) at certain locations compared to upstream sediments. Up to 2% of the total mercury in sediments containing coal ash was present as methylmercury. Mercury isotope composition and sediment geochemical data suggested that elevated methylmercury concentrations occurred in regions where native sediments were mixed with coal ash (e.g., less than 28% as coal ash in the Emory River). This coal ash may have provided substrates (such as sulfate) that stimulated biomethylation of mercury. The production of methylmercury in these areas is a concern because this neurotoxic organomercury compound can be highly bioaccumulative. Future risk assessments of coal ash spills should consider not only the leaching potential of mercury from the wastes but also the potential for methylmercury production in receiving waters.

Deonarine A; Bartov G; Johnson TM; Ruhl L; Vengosh A; Hsu-Kim H

2013-02-01

242

Remediação de drenagem ácida de mina usando zeólitas sintetizadas a partir de cinzas leves de carvão/ Remediation of acid mine drainage using zeolites synthesized from coal fly ash  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Zeolitic material was synthesized from coal fly ashes (baghouse filter fly ash and cyclone filter fly ash) by hydrothermal alkaline activation. The potential application of the zeolitic product for decontamination of waters from acid mine drainage was evaluated. The results showed that a dose of 30 g L-1 of zeolitic material allowed the water to reach acceptable quality levels after treatment. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters.

Fungaro, Denise Alves; Izidoro, Juliana de Carvalho

2006-07-01

243

Remediação de drenagem ácida de mina usando zeólitas sintetizadas a partir de cinzas leves de carvão Remediation of acid mine drainage using zeolites synthesized from coal fly ash  

Directory of Open Access Journals (Sweden)

Full Text Available Zeolitic material was synthesized from coal fly ashes (baghouse filter fly ash and cyclone filter fly ash) by hydrothermal alkaline activation. The potential application of the zeolitic product for decontamination of waters from acid mine drainage was evaluated. The results showed that a dose of 30 g L-1 of zeolitic material allowed the water to reach acceptable quality levels after treatment. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters.

Denise Alves Fungaro; Juliana de Carvalho Izidoro

2006-01-01

244

Radioactivity of coals and ash and slag wastes at coal-fired thermal power plants  

Science.gov (United States)

This paper presents an analysis of published data on the content of radioactive nuclides in coals originating from various coal deposits, and in ash and slag wastes produced at coal-fired thermal power plants, as well as in fly ash emitted from thermal power plants into the atmosphere. Problems related to the use of coals with an elevated content of natural radionuclides (NRNs) and methods of their solution implemented at the Urtuyskoe coalfield are dealt with. Data on the analysis of Transbaikal coals for the NRN content, as well as weighted mean content of uranium and thorium in coals from the Siberian Region, are given. In order to reduce irradiation of plant personnel and the population of the areas where coal producers and coal-fired thermal power plants are located, it is necessary to organize very careful control of the NRN content in both coals and products of their combustion that are released into the environment. To solve the problem related to the control of radioactivity, the centralized approach and creation of a proper normative base are needed. Experience gained in developing the Urtuyskoe coalfield shows that it is possible to create an efficient system of coal quality control with respect to the radiation hygiene factor and provide protection of the environment and health of the population.

Krylov, D. A.; Sidorova, G. P.

2013-04-01

245

Environmental evaluation of coal ash from Chandrapura Thermal Power Station of Damodar Valley Corporation  

International Nuclear Information System (INIS)

This study envisages the environmental assessment of coal ash disposal from Chandrapur thermal power station. Environmental evaluation of coal ash is made through the analysis of leachates from open percolation leaching column experiments and also from the actual ash pond disposal site over a period of 10 months. Results of this study indicated that leachate analysis from open percolation column experiments closely resembles leachate analysis of actual ash pond disposal site. The pH, conductivity, total dissolved solids and trace elements were observed with the regulatory limits. Overall this study reveals that coal ash from this power plant is environmentally benign. (author)

1998-01-01

246

Determination of beryllium and lithium in coal ash by inductively coupled plasma atomic emission spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

The use of graphite furnace atomic absorption spectroscopy for the direct determination of traces of Be in coal ash is shown to be difficult due to matrix interferences. The determination of Be and Li in coal ash by inductively coupled plasma atomic emission spectroscopy is discussed. Samples were prepared in Parr acid digestion bombs using a mixture of HNO/sub 3/ and HF. Results for some South African coal ash samples are presented.

Pougnet, M.A.B.; Orren, M.J.; Haroldsen, L.

1985-01-01

247

The experimental gamma-gamma probe for bulk analysis of ash content in coal  

International Nuclear Information System (INIS)

[en] This paper presents an experimental model of a spectrometric borehole gamma-gamma probe for ash determination in coal. The measurements are carried out on three coal samples with different ash contents. The best configuration of the probe was established. Several spectral parameters were tested and selected in order to find a good dependence on the ash content of coal samples. (author) 3 figs., 5 refs

1995-01-01

248

Removal rate of zinc from coal bottom ash in aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

The leaching of inorganics including heavy metals from coal ashes has recently received extensive attention. This study was undertaken to understand the rate of leaching of metals from coal ash and the significant factors affecting the rate, and to develop an approach to predict leaching rates. The rate of leaching of zinc was characterized quantitatively for one coal bottom ash using a pseudokinetic mechanism. The resulting rate constants were correlated over a pH range of 1.3-9.3.

Roth, J.A.; Debelak, K.A.; Feather, K.F.

1983-01-01

249

Fly ash and coal conversion by-products: characterization, utilization and disposal I  

Energy Technology Data Exchange (ETDEWEB)

24 papers are presented discussing the characterization of fly ash and ash-containing mortars/concrete by x-ray diffraction, scanning electron microscopy and thermal analysis, as well as by petrographic microscopy metallography, and microfocus Raman spectroscopy; the possibility of using coal as a principal aluminum source in the event of a bauxite shortage; the formation of an artificial reef from coal waste, and application in roadbed stabilization; determination of free lime (CaO) in fly ash; characterization of a lignite ash from the METC gasifier, flexural strength and fracture of a fly ash blended cement; and disposal of fly ash in the northern Great Plains.

McCarthy, G.J.; Lauf, R.J. (eds.)

1985-01-01

250

Coal Ash Behavior in Reducing Environments  

Energy Technology Data Exchange (ETDEWEB)

A series of tests have been conducted on two coals with the PDTF under various conditions (temperatures ranging from 1100{degree} to 1500{degree}C, pressures ranging from 50 to 100 psi, O/C ratios ranging from 1.0 to 2.0, and residence times ranging from 5 to 13 seconds). In summary, the results from the pressurized drop-tube furnace testing show differences in the inorganic transformations as a function of temperature residence time and coal type. The gas atmosphere and pressure did not have a visibly substantial effect on the results. It is expected that in a full-scale system that is oxygen- and/or air-blown, the initial atmosphere that the particles see will be similar regardless of amount of oxygen/air, but during the later stages the gas compositions will be significantly different. This would impact the vapor species, such as sodium, the most. The formation of calcium sulfide appears limited by high temperatures and longer residence times. This is primarily due to the instability of calcium sulfide at high temperatures. Iron sulfide, formed form the pyrite content in the coal, has a kinetically limited life in the high temperature regions of a gasification reactor. The iron sulfide decomposes to form metallic iron and iron aluminosilicates. The iron sulfides wet the surfaces of aluminosilicates during gasification to form sticky capture layers on the outside of the particles. Assuming the residence time within the reactor is short, some of the iron sulfide will exit without total decomposition, resulting in a sticky surface for deposition. Sodium, generally organically associated, appears to form sodium sulfide upon initial volatilization and quickly condenses on the surfaces of coalescing clay particles. The sulfide is not stable for long in the environment and results in the formation of sodium aluminosilicates.

Benson, S.A.; Erickson, T.A.; Brekke, D.W.; Folkedahl, B.C.; Tibbetts, J.E.; Nowok, J.W.

1993-09-01

251

Hydrogen production by catalytic gasification of Hyper-coal (ash free coal extract)  

Energy Technology Data Exchange (ETDEWEB)

This paper reports a new study on hydrogen production by steam gasification of Hyper-coal (ash free coal extract) with potassium carbonate as a catalyst. The Hyper-coal was obtained by extraction of coal with 1-methylnaphthalene at 360{degree}C and finally by separation of solvent from the extract. It has been interesting to find that compared to raw coal, the use of Hyper-coal demonstrates threefold important advantages: (1) a much higher gasification rate; (2) much less loss of catalytic activity; (3) higher hydrogen concentration in the resultant gas. The catalytic steam gasification of Hyper-coal would potentially be a more efficient process for production of hydrogen in the future. 4 figs., 1 tab.

Jie Wang; Kinya Sakanishi; Ikuo Saito; Takayuki Takarada [National Institute of Advanced Industrial Science and Technology (Japan). Energy Technology Research Institute National Institute of Advanced Industrial Science and Technology (Japan). Energy Technology Research Institute

2005-07-01

252

Refractories for dry ash coal gasifiers  

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the findings of a 9-yr research program, sponsored by the US Department of Energy and conducted by the Bureau of Mines, to evaluate refractory liner materials for coal gasifier reactors. Commercially available refractories were exposed to coal gasifier reactor environments, reproduced in the laboratory with a high-temperature, high-pressure test facility, followed by extensive postexposure evaluation. Thirty-six castable or gunnable refractories and cements and 24 refractory brick were evaluated. The behavior of castable refractories reinforced with stainless steel fibers was also examined. Gas environments that were evaluated included steam, H/sub 2/, CO/sub 2/, CO, and typical high- and low-Btu gas mixtures. Exposure pressures ranged from 100 to 1,000 psig, temperatures from 500/sup 0/ to 1100/sup 0/C, for periods from 50 h to 2000 h. In some exposures, sodium and/or potassium hydroxide were introduced in order to simulate a high-alkali environment. It was found that intermediate- and low-alumina refractories produced from domestically available raw materials, rather than high-alumina refractories produced from imported raw materials, gave the best service as liner materials and that alkali attack was probably not a serious problem with most refractories. Based on the results of this program, good choices of refractory liner materials for gasifier reactors can be made. 7 references, 25 figures, 30 tables.

Sadler, L.Y. III; Heystek, H.; Raymon, N.S.; Clancy, T.A.

1984-01-01

253

Radioactivity of coals and ashes from Catalagzi coal-fired power plant in Turkey  

International Nuclear Information System (INIS)

The Catalagzi 'dot-less' coal-fired power plant (CFPP) is the Turkish CFPP that uses the hard coals produced in Zonguldak, located in the West Black Sea region of the country. Gamma-ray spectrometry was used to determine 226Ra, 232Th and 40K contents in pulverised coal, bottom ash and fly ash samples. The natural radionuclide concentrations in pulverised coal ranged from 29 to 61 Bq kg-1 for 226Ra, from 32 to 55 Bq kg-1 for 232Th and from 229 to 414 Bq kg-1 for 40K. The fly ash fraction gave concentrations ranging from 80 to 98 Bq kg-1 for 226Ra, from 64 to 85 Bq kg-1 for Th and from 754 to 992 Bq kg-1 for 40K, respectively. The enrichment factors from coal to fly ashes are 1.7, 2.24 and 2.6 for 232Th, 226Ra and 40K, respectively. Therefore, it is advisable to monitor the environmental impact of the power plant. (authors)

2012-01-01

254

Study on the ash fusion temperatures of coal and sewage sludge mixtures  

Energy Technology Data Exchange (ETDEWEB)

The coal, sewage sludge, water and chemical additives are milled to produce coal-sludge slurry as a substitute for coal-water slurry in entrained-flow gasification, co-gasification of coal and sewages sludge can be achieved. The ash fusion temperature is an important factor on the entrained-flow gasifier operation. In this study, the ash fusion temperatures (DT, ST, HT and FT) of three kinds of coals (A, B and C), two kinds of sewage sludges (W1 and W2) and series of coal-sewage blends were determined, and the mineral composition during the ash melting process was analyzed by X-ray diffraction (XRD). The results showed that the ash fusion temperatures of most coal-sewage blends are lower than those of the coals and sewage sludges. The ashes have different mineral composition at different temperature during the heating process. It was found that the mineral composition of AW1 blend ash is located in the low-temperature eutectic region of the ternary phase diagram of SiO{sub 2}-Al{sub 2}O{sub 3}-CaO. The minerals found in BW1 blend ash are almost the same as those in B coal ash. Kyanite is detected in CW1 blend ash, which results in the ash fusion temperatures of CW1 blend ash higher than those of C coal. We found that sodium mineral matters are formed because of NaOH added to W2, which can reduce the ash fusion temperature of coal-sewage blends. 27 refs., 6 figs., 2 tabs.

Li Weidong; Li Ming; Li Weifeng; Liu Haifeng [East China University of Science and Technology, Shanghai (China). Key Laboratory of Coal Gasification of Ministry of Education

2010-07-15

255

Volcanic ash in feed coal and its influence on coal combustion products  

Energy Technology Data Exchange (ETDEWEB)

The US Geological Survey and the University of Kentucky Center for Applied Energy Research are collaborating with an Indiana Utility to determine the physical and chemical properties of feed coal and coal combustion products (CCPs) from a coal-fired power plant. The plant utilizes a low-sulfur (.23--.47 weight percent S) coal from the Powder River Basin, Wyoming. Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analysis of feed coal samples identified two mineral suites. A primary suite (not authigenic) consisting of quartz (detrital and volcanic beta-form grains), biotite, and minor zircon and a secondary authigenic mineral suite containing calcite, alumino-phosphates (crandallite and gorceixite), kaolinite, quartz, anatase, barite, and pyrite. The authigenic minerals are attributed to air-fall and reworked volcanic ash that was deposited in peat-forming mires. The Powder River Basin feed coals contain higher amounts of Ba, Ca, Mg, Na, Sr, and P compared to other analyzed eastern coals. These elements are associated with alumino-phosphate, biotite, calcite, and clay minerals. The element associations are indicative of coal that incorporated volcanic ash during deposition. XRD analysis of CCPs revealed a predominance of glass, perovskite, lime, gehlenite, quartz, and phosphates with minor amounts of periclase, anhydrite, hematite, and spinel group minerals in the fly ash; and quartz, plagioclase (albite and anorthite), pyroxene (augite and fassaite), rhodonite, and akermanite in the bottom ash. Microprobe and SEM analysis of fly ash samples revealed quartz, zircon, monazite, euhedral laths of corundum with merrillite, hematite, dendritic spinels/ferrites, and rounded grains of wollastonite with periclase. The abundant Ca and Mg mineral phases in the fly ashes are related to the presence of carbonate, clay, and phosphate minerals in the feed coal. The Ca- and Mg-rich mineral phases in the CCPs can be attributed to volcanic minerals deposited in the peat-forming mire. Dissolution and alteration of these minerals occurred either in the peat-forming sate or during coalification/diagenesis contributing to the authigenic mineral suite. Additionally, detrital mineral input and epigenetic ground-water flow may have affected the geochemistry of the feed coal.

Brownfield, M.E.; Affolter, R.H.; Cathcart, J.D.; Brownfield, I.K.; Hower, J.C.; Stricker, G.D.; O' Connor, J.T.

2000-07-01

256

Natural radioactivity of coals from Upper Silesian Coal Basin and their ash content  

International Nuclear Information System (INIS)

[en] The results of the study of natural radioactivity of Upper Silesian's coal are presented. The histograms of contents of 226Ra, 228Ra and 40K in the main groups of carbon layers are given. Analysis of correlations between contents of natural radionuclides and ash content in different coal layers was made. The correlations were stated. 12 refs., 7 figs., 4 tabs. (author)

1988-01-01

257

Modification of combustion and fly-ash characteristics by coal blending  

Energy Technology Data Exchange (ETDEWEB)

Pilot-scale boiler trials were carried out to study the combustion and fly-ash precipitation characteristics of a series of two- and three-component bituminous coal blends of US and Canadian coals. It was found that the degree of carbon burn-out was highly dependent on the concentration of unreactive coal macerals in each blend, and that the addition of an unoxidised coal improved the burn-out of both of the oxidised coals tested. The base-to-acid ratio and the potential slagging temperature of the coal input ash provided reliable indicators of the structure of the furnace ash deposits. In all trials, the moderate slagging and fouling tendency of the US coal was reduced by blending with one or both of the high-ash fusion Canadian coals.

Lee, G.K.; Whaley, H.

1983-12-01

258

Magnetic separation of coal fly ash from Bulgarian power plants.  

UK PubMed Central (United Kingdom)

Fly ash from three coal-burning power plants in Bulgaria: 'Maritza 3', 'Republika' and 'Rousse East' were subjected to wet low-intensity magnetic separation. The tests were performed at different combinations of magnetic field intensity, flow velocity and diameter of matrix elements. It was found that all parameters investigated affected the separation efficiency, but their influence was interlinked and was determined by the properties of the material and the combination of other conditions. Among the fly ash characteristics, the most important parameters, determining the magnetic separation applicability, were mineralogical composition and distribution of minerals in particles. The main factors limiting the process were the presence of paramagnetic Fe-containing mineral and amorphous matter, and the existence of poly-mineral particles and aggregates of magnetic and non-magnetic particles. It was demonstrated that the negative effect of both factors could be considerably limited by the selection of a proper set of separation conditions. The dependences between concentration of ferromagnetic iron in the ash, their magnetic properties and magnetic fraction yields were studied. It was experimentally proved that, for a certain set of separation conditions, the yields of magnetic fractions were directly proportional to the saturation magnetization of the ferromagnetic components of the ash. The main properties of typical magnetic and non-magnetic fractions were studied.

Shoumkova AS

2011-10-01

259

Factors influencing acute toxicity of coal ash to rainbow trout (Salmo gairdneri) and bluegill sunfish (Lepomis macrochirus)  

Energy Technology Data Exchange (ETDEWEB)

The potentially toxic components in coal ash (ash particles, heavy metals) were evaluated in laboratory static, acute (96 hr) bioassays, both separately and in various combinations with extreme pH (5.0 and 8.5), using rainbow trout (Salmo gairdneri) and bluegill sunfish (Lepomis macrochirus). Ash particle morphology and metal distribution analysis, using electron microscopy and surface-subsurface analysis by ion microscopy, showed that metals could be either clumped or evenly distributed on the surface of fly ash. Surface enrichment on fly ash particles from electrostatic precipitators, as measured by ion microscopy, was found for cadmium, copper, chromium, nickel, lead, mercury, titanium, arsenic, and selenium. Bottom (heavy) ash was not acutely toxic to either fish species at concentrations of up to 1500 mg/l total suspended solids (TSS) at pH 5.0, 7.5, or 8.5. Fly ash particles were not acutely toxic to bluegill at levels up to 1360 mg/l TSS. Rainbow trout were highly sensitive to fly ash (25 to 60% mortality) at concentrations of 4.3 tp 20.5 mg/l TSS when dissolved metal availability was high but were not sensitive at higher particulate concentrations (58 to 638 mg/l TSS) when dissolved metals were low. When metals were acid-leached from fly ash prior to testing, no rainbow trout mortality occurred at TSS concentrations of up to 2350 mg/l TSS. When the percent of dissolved metal was high (e.g., 50-90 % of the total), fish mortality was increased. Rainbow trout were nearly two orders of magnitude more sensitive than bluegill when subjected to a blend of cadmium, chromium, copper, nickel, lead, and zinc. The two species were similar in their acute sensitivity to acidic pH at level at or below 4.0 and alkaline pH of 9.1.

Cherry, D.S.; Van Hassel, J.H.; Ribbe, P.H.; Cairns, J. Jr.

1987-04-01

260

Elution of coal ash components by leaching with sulfuric acid  

Energy Technology Data Exchange (ETDEWEB)

The leaching is reported of coal ash with 0-0.5 mol/l sulfuric acid solutions. The following results are reported: 1) the amount of elution increases rapidly when the sulfuric acid concentration rises above 0.005 mol/l; 2) elution of all the components studied proceeds rapidly, reaching approximate equilibrium after 15 minutes; 3) the final percentage leaching is not very high. Elution tests using column type permeation/leaching apparatus were also conducted. These showed that the elution characteristics of the various components varied greatly. 4 references, 14 figures, 2 tables.

Tamanaga, T.; Kosuge, K.; Hamada, Y.

1986-01-01

 
 
 
 
261

Mosses accumulate heavy metals from the substrata of coal ash  

Directory of Open Access Journals (Sweden)

Full Text Available Plants that are able to accumulate and tolerate extraordinarily high concentrations of heavy metals (hyperaccumulators) can be used for phytoremediation (removal of contaminants from soils) or phytomining (growing a crop of plants to harvest the metals). Two moss species, Bryum capillare Hedw. and Ceratodon purpureus Hedw., were tested as potential phytoremedies under in vivo conditions on a coal ash disposal site in the surroundings of Obrenovac (NW Serbia). The content of various heavy metals (iron, manganese zinc, lead, nickel, cadmium, and copper) in the mosses and substrata were investigated over a period of three years. Iron and zinc were found to have the highest concentration in the mosses.

Vukojevi? Vanja; Sabovljevi? Marko; Jovanovi? S.

2005-01-01

262

A new apparatus for measuring the ash content of coal  

International Nuclear Information System (INIS)

[en] The author describes the application of multi-channel analysis technique in measuring the ash content of coal in pipe. It analyzes the problems existing in the previous work, designs a new- type apparatus and a fast data acquisition system. Several high efficient methods are adopted to smooth spectrum data, to locate peak, to calculate peak area and to modify counter rate. It also discusses the affection of several factors to the measuring system and gives out the way to overcome them

2000-01-01

263

Floating cultivation of marine cyanobacteria using coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The aim was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. The viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine microalgae was investigated. The marine cyanobacterium Synechococcus sp. NKBC 040607 was found to adhere to floating CFA blocks in liquid culture medium. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

Matsumoto, M.; Yoshida, E.; Takeyama, H.; Matsunaga, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan). Dept. of Biotetechnology

2000-07-01

264

Determination of titanium in coal fly ash by ETAAS  

Energy Technology Data Exchange (ETDEWEB)

A method for the determination of titanium in coal fly ash by electrothermal atomic absorption spectrometry has been developed. Palladium acetate was used as a chemical modifier. The instrumental conditions, graphite furnace program, concentration of the modifier, interferences, the calibration and standard addition graphs were studied. The limit of detection was found to be 0.66 ng and the relative standard deviation was 2.4% for 10 determinations. The reliability of the method has been demonstrated by the spiked recoveries of titanium and by analyzing a standard reference material. 27 refs., 3 figs., 4 tabs.

Bhattacharyya, S.S.; Chakraborty, R.; Das, A.K. (Univ. of Burdwan (India))

1993-02-01

265

Correlation between ash fusion temperatures and chemical composition in Albanian coal ashes  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an analysis of the ash fusion temperatures (AFTs) for 17 Albanian coals. The contribution of oxides to AFTs is investigated by considering oxides from various perspectives: as discrete species, acids and bases, crystal components, fluxing agents, and cement constituents, and in accordance with the periodic table. Empirical correlations use simple and multiple linear equations and polynomial equations, referring to both weight and molar percentages. The shift from the deformation temperature to the flow temperature is accompanied by a shift of influence from basic oxides to acidic oxides. Many predictive correlative equations are obtained. 11 refs., 2 tabs.

Lolja, S.A.; Haxhi, H.; Dhimitri, R.; Drushku, S.; Malja, A. [University of Tirana, Tirana (Albania). Department of Industrial Chemistry

2002-12-01

266

Study on determining the ash content of the coal by low-energy ?-ray transmission techniques  

International Nuclear Information System (INIS)

[en] Single low-energy ?-ray transmission techniques for determining the ash content of the coal have higher sensitivity than the back-scattering method. Transmission techniques are suitable for measuring not only the low ash content, but also the high ash content. The authors deduce the equations determining the ash content of the coal by single low-energy ?-ray transmission techniques and calculate the errors due to the composition changes. The effect of constituent variations on determining the ash by transmission techniques is the same as back-scattering methods. Measurement errors in the laboratory are less than ±0.40%

1989-01-01

267

Investigation of the suitability of coal ash as a banking material  

Energy Technology Data Exchange (ETDEWEB)

Laboratory experiments have furnished noteworthy results relating to the use of coal ash for banking or land-fill in coastal or inland areas. It was found, for example, that the pozzolanic activity of coal ash is enhanced by the use of sea-water, and that the compaction characteristics and strength of ash are markedly improved by prior mixture with high water content (dry weight basis) cohesive soil. It was also found that both the unconfined compression strength and the maximum dry density of soil/ash mixtures increased with increasing ash mixing ratio.

Yamamoto, Y.; Ohki, R.; Hayazaki, T.

1984-01-01

268

Radon and thoron flux densities from some of NSW coal ash dams  

Energy Technology Data Exchange (ETDEWEB)

The use of coal as an energy source can cause some potential environmental and human health hazards associated with radionuclides mobilized by the coal fuel cycle. The objective of this study was to assess environmental significance of radon and thoron emissions from New South Wales coal ash storage dams operated by Pacific Power. To achieve this objective radon and thoron flux densities were measured from selected ash dams and mine spoil areas. It was found that: (i) ash dams currently in operation exhibit significantly lower flux densities than average values for Australian soils, and (ii) ash dams under rehabilitation and mine spoils have flux densities comparable to Australian soil. 18 refs., 2 tabs.

Zahorowski, W.; Whittlestone, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Malfroy, H.; Davies, P. [Pacific Power Ltd., Sydney, NSW (Australia)

1994-12-31

269

Development of the ash content measurement in coal by nuclear technique  

International Nuclear Information System (INIS)

[en] Neuclear techniques used for measuring the ash content in coal are applied extensively in coal industry. The basic principles of various methods for ash determination are introduced. The advantages and disadvantages of these methods and their application conditions are also reviewed

1989-01-01

270

The effect of frothers on beneficiation of high and low ashed Zonguldak coal by column flotation  

Energy Technology Data Exchange (ETDEWEB)

This study analyses the beneficiation of fine Zonguldak coal (80% under 0.500 mm) samples with various ash level by column flotation using different frother reagents. In addition the effects of ash level and different frother reagents on column flotation of fine coal are investigated. 5 refs., 1 fig., 1 tab.

Cocen, I.; Cilingir, Y.; Malayoglu, U. [Dokuz Eylul University, Izmir (Turkey). Dept. of Mining Engineering

1994-12-31

271

Characteristics of fly ash from laboratory combustion of pulverized coal  

Energy Technology Data Exchange (ETDEWEB)

Submicron particles generated from pulverized coal combustion show an enrichment of certain trace elements that may be a health hazard when ingested into the lung. Sieved pulverized coal was entrained in an air/methane/oxygen mixture and burned in an enclosed bunsen type burner fitted with a chimney. Cold secondary air was injected at the chimney exit. The fly ash samples were separated into two size categories (diameter < 2.5 ..mu.. and 2.5 ..mu.. < diameter < 15 ..mu..) and analyzed by x-ray fluorescence. Results show enrichment of several volatile elements in the small size fraction compared to the large size fraction. There is also indication of depletion of some refractory elements. The results support suggestions of several earlier observations which were made on full scale modern boilers.

Parsons, G.; Sherman, P.; Greif, R.; Robben, F.

1981-09-01

272

Characteristics of phosphate adsorption onto granulated coal ash in seawater  

Energy Technology Data Exchange (ETDEWEB)

The deterioration of sediments is a serious environmental problem. Controlling nutrient release fluxes from sediments is important to alleviating eutrophication and to reducing terrigenous nutrient loads. The purpose of this study was to evaluate the phosphate removal performance of granulated coal ash (GCA) from seawater, which is produced from coal thermal electric power generation. Batch experiments were carried out to investigate the removal kinetics of phosphate from seawater under both oxic and anoxic conditions. Phosphate was removed well from seawater under both oxic and anoxic conditions. The adsorption isotherm for phosphate revealed that GCA could remove phosphate effectively from seawater above a concentration of 1.7 {mu} mol L{sup -1}. GCA can reduce the concentration of phosphate in seawater effectively under anoxic conditions where iron type adsorbents cannot be applied. Therefore, GCA could potentially be used to adsorb phosphate in the organically-enriched sediment, which generally occurs under highly reductive conditions.

Asaoka, S.; Yamamoto, T. [Hiroshima University, Higashihiroshima (Japan)

2010-08-15

273

Modification of combustion and fly-ash characteristics by coal blending  

Energy Technology Data Exchange (ETDEWEB)

Pilot-scale boiler trials were conducted to study the combustion and fly-ash precipitation characteristics of a series of two- and three-component bituminous coal blends. The blends consisted of a partially oxidized eastern US coal with selected additions of either a western Canadian oxidized coal and/or a western Canadian unoxidized coal. It was found that the degree of carbon burn-out was highly dependent on the concentration of unreactive coal macerals in each blend. and that additions of the Canadian unoxidized coal improved the burn-out of both the US and Canadian oxidized coals. For blends with about 50% US coal the fly-ash resistivity decreased dramatically as the combustible in fly-ash exceeded 12%. The base-to-acid ratio and the potential slagging temperature of the coal input ash provided reliable indicators of the structure of the furnace ash deposits. In all trials, the moderate slagging and fouling tendency of the US coal was reduced by blending with one or both of the high-ash fusion Canadian coals.

Lee, G.K.; Whaley, H.

1983-12-01

274

Application of coal ash to civil engineering material. Interim report(5) Reclamation of grassland and farmland using coal ash (Part 2). Sekitanbai no dobokuzairyo eno riyo. Chukanhokoku(5)  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the progress of farmland reclamation and cultivationo of crops and the results of improving the Kuroboku-stony trass and heavy clay by coal ash. The following tests were made: reclamation of grassland in the ash landfill of a thermal power plant and in the site of laboratory; relationship between the reclamation of municipal farmland of Ebetsu by coal ash and pH of soil; cultivation of crops at coarse particle-ash blended earth and cultivation of pasture at mixed soil of heavy clay and clinker. When the soil is covered with a thickness of 25 cm or more of ash, less damage caused by drying, normal growth of crops and low pH are expected. It is necessary for applying coal ash to the agricultural ground improvement to lay covered conduit at the bottom of ground in order to prevent the foundation of agricultural land from breaking and to drain off the water derived from a big rainfall. The goal was almost attained in the cultivation of pasture by using the mixed soil of Kuroboku-stony trass and coarse particle ash. The synergistic effect of the effect by exchanging the sandy soil with clinker for improving the heavy clay and the adjustment of pH of soil was observed. The experimental study on the relationship between the chemical substances contained in coal ash and the animals including the human and plants will be needed. (7 figs, 5 tabs, 2 photos)

Igarashi, Kazuhiko; Yoshida, Osamu

1985-12-01

275

Application of Coal Ash to Civil Engineering Material.Interim Report(5) Reclamation of Grassland and Farmland Using Coal Ash (Part 2).  

Science.gov (United States)

This paper presents the progress of farmland reclamation and cultivationo of crops and the results of improving the Kuroboku-stony trass and heavy clay by coal ash. The following tests were made: reclamation of grassland in the ash landfill of a thermal p...

K. Igarashi O. Yoshida

1985-01-01

276

Rapid determination of ash content in coal by X-ray method  

International Nuclear Information System (INIS)

[en] With a 109Cd source, the Compton scattering intensity and the X-ray fluorescence intensity of Fe in coal were used to determine the ash content in coal. The maximum deviation was less than ±1.5% for the ash contents from 6% to 50%, and the relative error in comparison with the gravimetry was less than ±1.5%. In this paper, the use of different radioisotope sources to determine the ash contents was also discussed

1989-01-01

277

Development of a process for the production of lightweight man-made aggregate from coal ash  

Energy Technology Data Exchange (ETDEWEB)

The authors outline a process for the production of lightweight, man-made aggregate from coal ash. The process, aimed at the active utilization of this major waste product, has passed through the research and development stage and is now successfully established. In its final form, it involves the humidified pelletizing of coal ash, followed by spontaneous sintering in a sinter band furnace via the heat released from the uncombusted carbon in the ash. 5 references.

Kawabe, A.; Kurashima, Y.; Umashima, T.; Hamashima, K.; Nagao, S.

1984-01-01

278

Development of a process for the production of man-made, lightweight aggregate from coal ash  

Energy Technology Data Exchange (ETDEWEB)

The authors report the development and successful application of a process for producing a lightweight aggregate from coal ash. The process involves the hot pelletizing of coal ash, followed by spontaneous sintering in a sinter band furnace using the heat released from the combustion of the unburnt carbon present in the ash. The new process uses less energy than existing processes for lightweight aggregate production. 4 references.

Nagao, S.; Kubo, Y.; Toriyao, M.

1984-01-01

279

Composition and morphology of fly ash from fluidized bed combustion of brown coal  

Energy Technology Data Exchange (ETDEWEB)

The chemical composition and morphology of fly ash captured in cyclone, bottom ash and ultrafine particles separated in the low pressure impactor produced by the two modes of combustion (oxidation and reduction conditions) are determined. The two types of brown coal from the North Bohemian basin are characterized by reflectance, maceral, mineralogical and chemical composition. It was found that composition and morphology of fly ash depends on reaction conditions, coal quality and size distribution of particles. (orig.)

Sykorova, I. [Academy of Sciences, Prague (Czech Republic). Inst. of Rock Structure and Mechanics; Smolik, J.; Schwarz, J. [Academy of Sciences, Prague (Czech Republic). Inst. of Chemical Process Fundamentals; Kerkkonen, O. [RAUTARUUKKI OY, Rahe (Finland); Kucera, J.; Havranek, V. [Ceskoslovenska Akademie Ved, Rez (Czechoslovakia). Ustav Jaderne Fyziky

1997-12-31

280

Natural Radionuclides in Slag/Ash Pile from Coal-Fired Power Plant Plomin  

International Nuclear Information System (INIS)

[en] Full text: The coal slag/ash pile contains about one million tons of different (bottom ash, filter ash, gypsum) waste material deposited in vicinity of Plomin coal-fired power plant. Activities of 40K, 228Ra, 226Ra and 238U in materials deposited on slag/ash pile as well as in used coals were occasionally measured during past more than two and half decades of Plomin coal-fired plant operation. The radionuclides content in deposited bottom and filter ash material are related with radionuclide activities and mineral matter fraction in coals used. Up to the middle of nineties, the majority of coal used was anthracite from Istrian local mines. In that period, deposited waste material was characterised with relatively high 226Ra and 238U activities while potassium and thorium content was very low. When Istrian coal has been completely substituted with imported coal, uranium series radionuclide concentrations in deposited waste materials decreased significantly. Meanwhile, potassium and thorium activities in slag/ash pile material increased. It seems that slag/ash pile material generated in the last several years of Plomin coal-fired power plant operation could be generally used in cement industry without any special restriction. (author)

2001-01-01

 
 
 
 
281

Assessing dynamics of ash content formation in coal at a working face in mines  

Energy Technology Data Exchange (ETDEWEB)

Factors which influence ash content in coal mined at a working face are analyzed: ash content in coal, stability of rock layers surrounding a coal seam, mechanical and physical properties of the direct roof. A mathematical model of ash content formation at a working face is described. On the basis of the model a computer program has been constructed. The program is used for calculating the mean value of ash content in coal and the standardized deviation. The program considers all causes of ash fluctuation in coal such as mining conditions, coal seam thickness, fluctuations in coal seam thickness, mechanical and physical properties of rocks surrounding a coal seam, particularly in the direct roof, mining systems, narrow or wide web shearer loaders, powered supports, hydraulic props, timber friction props with timber roof bars or with steel roof bars. A classification of rocks considering roof stability used by the program is described. A scheme of the program is given. Examples of using the program for forecasting ash content in coal and ash content fluctuations in Donbass mines are evaluated. (In Russian)

Maidukov, G.L.; Lobkin, V.M.

1983-05-01

282

Physical properties of cultivated soils mixed with coal ash as ameliorant  

Energy Technology Data Exchange (ETDEWEB)

This study was carried out to promote the utilization of coal ash from coal-fired power plant as soil improving agent by mixing with agricultural soil. Fly ash and bottom ash were mixed with four soils (alluvial soil, volcanic ash soil, Masa soil, and sand) at the mixing rates of 0, 10, 30 and 50% respectively. Physical parameters such as soil texture, bulk density, three phase of soil, hydraulic conductivity, and water retention curve were measured. By fly ash application, there were consistent increases in fine sand and silt ratio, bulk density, solid ratio, and water-holding capacity, and a decrease in hydraulic conductivity (except alluvial soil). By bottom ash application, there were increases in coarse sand ratio, porosity, and hydraulic conductivity in all soils tested. Fly ash application was effective to improve physical properties of sandy soil. Bottom ash was effective to improve physical properties of alluvial and Masa soil.

Okabe, K.

1986-01-01

283

Application of dry separative methods for decreasing content the residues unburned coal and separation Fe from black coal flies ash  

International Nuclear Information System (INIS)

[en] Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss on ignition - LOI. In present, the valid STN and EU standard limits the content of LOI to 3 - 5 %, in national conditions maximum 7 %. Application of processing technologies also has to assure utilization of fly ash that provides a possibility of complex utilization of individual products obtained by modification. By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburned coal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOI of dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conducting product contained 7,72 % of LOI at 73 % of weight yield. (authors)

2008-01-01

284

Fire sand (coal ash derived sand) and whisker sand (coal ash derived sand with carbon fibre reinforcement)  

Energy Technology Data Exchange (ETDEWEB)

Fire sand is prepared from coal ash and cement, while whisker sand is fire sand with 0.5-5% addition of carbon fibre. Fire sand is lightweight, has good heat insulating properties and is strong enough to be used as a building material. Whisker sand retains all these characteristics, and in addition, possesses high flexural strength. Fire sand can be used for filtering feedwater or waste water, for the construction of sand piles (sand drains), and as a soil improver. Whisker sand also has several possible uses, e.g., as a facing material in construction and as a spray-on material. 5 refs., 17 figs., 8 tabs.

Yamamoto, T.

1986-01-01

285

Tests of effective utilization of industrially produced materials: soil engineering properties and earthworking problems of coal ash and red mud  

Energy Technology Data Exchange (ETDEWEB)

An account of problems arising in the use of coal ash and red mud as filling or banking materials. The soil engineering properties of these materials are explained. Problems encountered in on-site use include difficulty in controlling moisture content, absorption swelling and strongly alkaline atmospheres. For long-term use, it will be necessary to minimize the variations in engineering characteristics and in quality that result from the method of discharge and from the raw materials themselves. There must also be thorough quality control during shipment. (7 refs.) (In Japanese)

Ogino, H.; Noto, S.; Shimatani, N.; Kudo, S.

1982-01-01

286

Mineralogy and microstructure of sintered lignite coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Lignite coal fly ash from the 'Nikola Tesla' power plant in Yugoslavia has been characterised, milled, compacted and sintered to form monolithic ceramic materials. The effect of firing at temperatures between 1130 and 1190{sup o}C on the density, water accessible porosity, mineralogy and microstructure of sintered samples is reported. This class C fly ash has an initial average particle size of 82 {mu}m and contains siliceous glass together with the crystalline phases quartz, anorthite, gehlenite, hematite and mullite. Milling the ash to an average particle size of 5.6 m, compacting and firing at 1170{sup o}C for 1 h produces materials with densities similar to clay-based ceramics that exhibit low water absorption. Sintering reduces the amount of glass, quartz, gehlenite and anhydrite, but increases formation of anorthite, mullite, hematite and cristobalite. SEM confirms the formation of a dense ceramic at 1170{sup o}C and indicates that pyroplastic effects cause pore formation and bloating at 1190{sup o}C. 23 refs., 6 figs., 2 tabs.

Marina Ilic; Christopher Cheeseman; Christopher Sollars; Jonathan Knight [Faculty of Technology and Metallurgy, Belgrade (Yugoslavia)

2003-02-01

287

Determination of ash in Turkish coal using backscattering in X ray fluorescence techniques  

International Nuclear Information System (INIS)

X ray fluorescence, using backscattering, was employed in the determination of ash in as-received forms of Turkish coal. Fluorescent intensities from the major components of mineral matter in coal, Ca, Ti, Fe and their combinations were used conjunction with the reciprocal of the backscattering intensity in an empirical relationship. Since the aim was to develop a method of coal ash analysis with a rapid analysis time, 238Pu was chosen as the excitation source. Approximately sixty Turkish coal samples from different seams were analysed by this method; the results show that the ash content in samples varies from 8 to 40%. (author). 10 refs, 4 figs, 2 tabs.

1991-01-01

288

Uranium content in coal and fly ash samples  

International Nuclear Information System (INIS)

[en] In the present study, we have measured the U-content in coal samples of different collieries used as fuel in Thermal Power Plant, Kasimpur (U.P.) and in the fly ash collected from there. The samples were ground very finely and sieved through a 100 mesh sieve. The sample powder and methyl cellulose powder (a binder free from uranium contamination) were mixed in the ratio 1:2 by weight. Thin pellets of this mixture (? 1.3 cm dia) was made by a hydraulic tablet making machine. These pellets were sandwiched between a pair of washed, cleaned and dried plastic track detector (Makrofol KG). These pellets along with a pellet of standard glass of known U-content were irradiated with a thermal neutron dose of 1015 (nvt) in the 'APSARA' reactor at Bhabha Atomic Research Centre, Bombay. After irradiation the detectors were separated and etched in 6.25M KOH at 80 C for 20 minutes. The resulting tracks were counted. The U-content in coal shows a variation of 1.07 to 6.67 ppm in uniform distribution and 26.82 to 46.74 ppm in non-uniform distribution. In fly ash the U-content varies from 6.83 to 9.48 ppm in uniform and from 51.73 to 64.50 ppm in non-uniform distribution. (author). 5 refs., 2 tabs

1991-01-01

289

Selenium in onions grown in media amended with coal fly ashes collected with differing efficiencies  

Energy Technology Data Exchange (ETDEWEB)

Whether the particle size distribution of fly ash influences selenium uptake by onions grown on coal fly ash-amended growth media was investigated. Two fly ashes having differing percentages of finely sized particles were used as plant growth amendments at percentages in the media to yield equal concentrations of selenium. Selenium concentrations in the harvested onion bulbs were found to be independent of fly ash particle size distribution.

Gutenmann, W.H.; Doss, G.J.; Lisk, D.J. [Cornell University, Ithaca, NY (United States). New York State College of Agriculture and Life Sciences, Dept. of Fruit and Vegetable Science

1998-08-01

290

A methodology to evaluate coal ash content using Siderite Moessbauer spectral area  

Energy Technology Data Exchange (ETDEWEB)

A methodology was used to evaluate Low Temperature Ash (LTA) and High Temperature Ash (HTA) through Moessbauer Spectroscopy (MS). Siderite was the only Moessbauer Spectral presenting a good correlation between the spectral area and the ash content obtained by LTA and HTA. The calibration curves obtained for HTA and LTA gave a correlation coefficient of 0.968 and 0.988, respectively. The LTA results present the best correlation, given that this process does not change the original mineral phases. This methodology was the advantageous for easily obtaining coal ash content, through curve ash content vs. MS area, without carrying out ashing processes. Short communication. 5 refs., 3 figs., 2 tabs.

G. Medina; J.A. Tabares; G.A. Perez Alcazara; J.M. Barraza [Universidad del Valle, Cali (Colombia). Department of Physics

2006-03-15

291

Adsorption of indigo carmine from aqueous solution using coal fly ash and zeolite from fly ash  

International Nuclear Information System (INIS)

[en] Coal fly ash, a waste generated at the Figueira coal-fired electric power plant located in Brazil, was used to synthesize zeolite by hydrothermal treatment with NaOH solution at 100 deg C for 24 h. The fly ash (FA) and this synthesized zeolite (ZM) that was characterized predominantly as hydroxy-sodalite were used as adsorbents for anionic dye indigo carmine from aqueous solutions. The samples were analyzed by instrumental neutron activation analysis (INAA) for the determination of As, Co, Fe, La, Mo, Na, Sb, Sc, Sm, Th, U and Zn. Effects of contact time and initial dye concentration were evaluated in the adsorption processes. The kinetics studies indicated that the adsorption followed the pseudo-second order kinetics and that surface adsorption and intraparticle diffusion were involved in the adsorption mechanism for both the adsorbents. The Langmuir isotherm model provided the best correlation of the experimental data. The maximum adsorption capacity was found to be 1.48 mg L-1 for FA and 1.23 mg L-1 for ZM. Laboratory leaching and solubilization tests conducted to classify this ZM as if was a waste residue according to the Brazilian regulation classified it as a residue non-hazardous and non-inert. (author)

2011-01-01

292

Influence of sewage sludge addition on Shenfu coal ash fusion temperatures  

Energy Technology Data Exchange (ETDEWEB)

The ash fusion characteristics of Shenfu coal (A), sewage sludge (WI), modified sewage sludge (W2) and the mixture of coal and sewage sludge (AWI, AW2) were studied. The Shenfu coal with the addition of WI and W2 has lower fusibility temperature than coal and sludge. When 30.74 g WI ash is added to A ash, the ash fusion temperature reduces by 63{sup o}C and reaches the lowest point, and when 51.23 g W2 ash is added to A ash, the ash fusion temperature decreases by 82{sup o}C and reaches the minimum. The analysis of the mineral matter of coal, sewage sludge and mixture was conducted by XRD diffractograms and the transformation of mineral matter in the mixture of AWI, AW2 at different temperatures was compared. The result shows that chloroapatite is formed and the transformation temperature of quartz, anhydrite, and hematite decreases when WI is added to coal; while plenty of sodium in W2 and the transformation of sodium-mineral matters in W A2 coal-sewage sludge mixture at different temperatures are the main reasons for the lowering of ash fusion temperature. 17 refs., 5 figs., 1 tab.

Li Ming; Li Wei-dong; Li Wei-feng; Liu Hai-feng; Yu Zun-hong [East China University of Science and Technology, Shanghai (China). Key Laboratory of Coal Gasification of Education Ministry of China

2009-08-15

293

Monitor of ash content of coal with X-ray source  

International Nuclear Information System (INIS)

[en] The coal ash monitor is used on-line to measure the ash content of raw, washed and blended coals. The instrument consists of a presentation unit and electronic unit. In the presentation unit a compact layer of coal is formed and there is also a radiation measuring system. A plutonium 238 source is used and the backscattered X-rays are detected by a proportional counter. The count rate is processed in the electronic unit and displayed as the ash percentage in the coal. A wide range of Polish coals was analysed. The monitor was tested in a power plant over the period of one year. The ash content in the coal analysed was in the range 5 to 50%. The gauge readings were compared with the pyrolysis results. An accuracy of 3.2% (95% confidence limit) was reached. These results were not corrected for the free moisture content which varied in the range 5 to 15 %. (author)

1982-10-01

294

Design and testing controlled low-strength materials (CLSM) using clean coal ash  

Energy Technology Data Exchange (ETDEWEB)

The major objective of this project was to develop mixture proportions for controlled low-strength material (CLSM) using clean coal ash obtained from atmospheric fluidized bed combustion (AFBC). A clean coal ash is defined as the ash derived from SO{sub x} and NO{sub x} control technologies. The specific ashes used for this project were: (1) circulating fluidized bed boiler fly ash and bottom ash and (2) stoker-type boiler fly ash and bottom ash. These two coal ash samples were characterized for physical and chemical properties. Chemical properties and water leaching tests were also performed on the hardened CLSM. Many initial CLSM mixtures were developed by blending the two types of ash. Tests conducted on the final three selected CLSM mixtures included compressive strength, bleeding, setting and hardening, settlement, length change of hardened CLSM, permeability, mineralogy, and chemical water leach testing. Results show that acceptable CLSM material can be developed by blending the fluidized bed boiler ash with the stoker boiler ash. Recommendations for a pilot scale manufacturing application of the three CLSM mixtures were made based upon the lab test results.

Naik, T.R.; Kraus, R.N. [Univ. of Wisconsin, Milwaukee, WI (United States); Sturzl, R.F. [Manitowoc Public Utilities, WI (United States); Ramme, B.W. [Wisconsin Electric Power Co., Milwaukee, WI (United States)

1998-10-01

295

JV Task 120 - Coal Ash Resources Research Consortium Research  

Energy Technology Data Exchange (ETDEWEB)

The Coal Ash Resources Research Consortium{reg_sign} (CARRC{reg_sign}, pronounced 'cars') is the core coal combustion product (CCP) research group at the Energy & Environmental Research Center (EERC). CARRC focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of CCPs. CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCP utilization and ensuring its successful application. The U.S. Department of Energy is a partner in CARRC through the EERC Jointly Sponsored Research Program, which provides matching funds for industrial member contributions and facilitates an increased level of effort in CARRC. CARRC tasks were designed to provide information on CCP performance, including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC technical research tasks are developed based on member input and prioritization. CARRC special projects are developed with members and nonmembers to provide similar information and to support activities, including the assembly and interpretation of data, support for standards development and technology transfer, and facilitating product development and testing. CARRC activities from 2007 to 2009 included a range of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCPs. The tasks were included in four categories: (1) Environmental Evaluations of CCPs; (2) Evaluation of Impacts on CCPs from Emission Controls; (3) Construction and Product-Related Activities; and (4) Technology Transfer and Maintenance Tasks. All tasks are designed to work toward achieving the CARRC overall goal and supporting objectives. The various tasks are coordinated in order to provide broad and useful technical data for CARRC members. Special projects provide an opportunity for non-CARRC members to sponsor specific research or technology transfer consistent with CARRC goals. This report covers CARRC activities from January 2007 through March 2009. These activities have been reported in CARRC Annual Reports and in member meetings over the past 2 years. CARRC continues to work with industry and various government agencies with its research, development, demonstration, and promotional activities nearing completion at the time of submission of this report. CARRC expects to continue its service to the coal ash industry in 2009 and beyond to work toward the common goal of advancing coal ash utilization by solving CCP-related technical issues and promoting the environmentally safe, technically sound, and economically viable management of these complex and changing materials.

Debra Pflughoeft-Hassett; Loreal Heebink; David Hassett; Bruce Dockter; Kurt Eylands; Tera Buckley; Erick Zacher

2009-03-28

296

The partitioning behaviour of boron from tourmaline during ashing of coal  

Energy Technology Data Exchange (ETDEWEB)

Boron is an environmentally sensitive element that may be present in high concentrations in some coals. Three modes of occurrence for boron in coal are commonly recognised, namely, bound to the organic fraction, locked into clay minerals (mainly illite), and bound within the crystal lattice of tourmaline. The organically bound mode is generally considered to be the most likely. Following combustion in a pulverised fuel utility, boron is generally enriched in the fine fly ash waste, but in some cases, it may also escape with the flue gas, suggesting variable partitioning behaviour. There is concern that boron may be leached from fly ash disposal impounds at concentrations toxic to higher land plants. A coal sample from the D Seam of the Strongman No. 2 Mine, West Coast, South Island, New Zealand has been used to test the hypothesis that boron present in tourmaline is less volatile in coal combustion, implying that mode of occurrence is a key control on the partitioning behaviour of this element. Six sample subsets were doped with increasing amounts of ground tourmaline. One subsample from each set was analysed by prompt gamma INAA to determine the concentration of boron in the coal. Two subsamples were ashed at 1000 C. One ash sample from each set was analysed for boron, while the other ash sample was leached according to Australian standards. It was found that the relationship between boron in the doped coal and boron in the ash is approximately linear (with some losses noted during ashing), indicating boron present in tourmaline was substantially retained in the ash. Furthermore, no relationship was found between the boron content of the ash and boron leached from the ash samples by reagent water. The results suggest boron present in coal as tourmaline is retained in the ash and is unavailable to the environment following fly ash disposal.

Boyd, R.J. [James Cook University, Henderson, KY (Australia)

2002-12-01

297

Microcomputer technique in on-line measurement of the ash content of coal  

International Nuclear Information System (INIS)

[en] The on-line measurement of the ash content of coal is a key technique urgently needed in coal industry. In principle it can be realized using nuclear technology. But it is practical only when microcomputer is introduced. The paper describes the microcomputer technique used in the on-line measurement of the ash content of coal by bi-energy ? ray transmission method

1996-01-01

298

Determination of radioactive trace elements in ashes and fly-ashes from Brazilian coal-fired power plants  

International Nuclear Information System (INIS)

[en] The aim of this work was to apply a epithermal neutron activation technique to determine the uranium and thorium content in coal ashes and fly ashes from Brazilian coal-fired thermoelectric plants and to evaluate the contribution of these elements and their descendents to the environmental radioactivity. Brazil has adopted as short term policy the use of alcohol and coal as alternative sources of energy. With regard to coal, large deposits of this mineral are found in southern states but the serious problem of its utilization is the risk of environmental contamination which can reach dangerous levels because the industrial plants burn several million tons per year. Uranium and thorium contents, determined experimentally, are extrapolated for annual coal consumption and their amounts and the activity of the radium isotopes descendents released to the atmosphere are calculated. The significance of these values and problems in environmental pollution are discussed

1984-01-01

299

Dynamic formation of zeolite synthesized from fly ash by alkaline hydrothermal conversion.  

UK PubMed Central (United Kingdom)

This study was designed to characterize the dynamic formation of zeolite synthesized from fly ash (ZFA) and to identify the zeolitization mechanisms during a 160-h-long hydrothermal alkaline conversion at 95°C by using fly ash (FA) samples collected from four typical thermoelectric power plants in China, with the purpose of improving ZFA quality. The process of synthesizing ZFA can be fundamentally divided into five stages: induction stage (0-0.5 h), accelerating dissolution stage (0.5-12 h), nucleation and/or crystallization stage (12-24 h), crystal growth stage (24-72 h) and crystal transformation stage (72-160 h). The crystal growth stage determined the quality of zeolite crystallization, coupled with functions of re-assembling the silicon-aluminium tetrahedral network and developing submicro- and/or nanometer microstructure. A 48-h-long hydrothermal conversion generated ZFAs that had a greater specific surface area (26.0-89.4 times) and cation exchange capacity (29.6-71.0 times) than FA, which successfully sequestrated 41-95% of ammonium and 75-98% of phosphate from swine manure. However, over-reaction resulted in more stable hydroxysodalite and/or sodalite, surface agglomeration and cracking, and energy wasting. This work suggests that the reuse of recycled synthesis materials should occur during the fourth step (24-72 h).

Zhang Z; Li J; Li H; Wang H; Zhu J; He Q

2013-09-01

300

Coal fly ash and synthetic coal fly ash aggregates as reactive media to remove zinc from aqueous solutions.  

Science.gov (United States)

Coal fly ash (CF) and synthetic coal fly ash aggregates (SCFAs) were evaluated as low-cost reactive media for the remediation of groundwater contaminated with Zn. The SCFAs were prepared by mixing CF, sodium silicate, and deionized (DI) water. Serial batch kinetic and static tests were conducted on both CF and SCFAs, under various conditions (i.e., pH, initial Zn concentration, reaction time, and solid dosage), using Zn(NO(3))(2).6H(2)O solutions. Serial column tests were also conducted on both CF and SCFAs. The final rather than the initial pH of the solution had a greater effect on the removal of Zn. At pH>7.0, the removal of Zn was due to precipitation, whereas at <7.0, the removal of Zn was due to adsorption onto the reactive media. The removal of Zn increased with increasing dosage of the reactive medium and decreasing initial Zn concentration. The results of the column and batch tests were comparable. Preferential flow paths were observed with CF, but not SCFA. The hydraulic conductivity of CF was more significantly decreased than that of SCFA with increasing dry density of the specimen. PMID:18805638

Hong, Jung-Ki; Jo, Ho Young; Yun, Seong-Taek

2008-08-13

 
 
 
 
301

Studying the melting behavior of coal, biomass, and coal/biomass ash using viscosity and heated stage XRD data  

DEFF Research Database (Denmark)

The use of biomass for power generation can result in significant economical and environmental benefits. The greenhouse emissions can be reduced as well as the cost of the produced electricity. However, ash-related problems, including slagging, agglomeration, and corrosion, can cause frequent unscheduled shutdowns, decreasing the availability and increasing the cost of the produced power. In addition, the fouling of the heat exchange surfaces reduces the system efficiency. In this work the melting and rheological properties of various biomass and biomass/ coal ash samples were studied by using a high-temperature rotational viscometer and a hot stage XRD. The produced data were used to calculate the operating temperature of a pilot-scale entrained flow reactor during the cocombustion of biomass/ coal samples in order to ensure the slag flow and to avoid corrosion of the walls due to liquid slag/metal interaction. Biomass ash proved to have significantly different melting behavior compared to that of the coal ash. Furthermore, the addition of biomass to coal ash led to lower viscosity and subsequently to higher stickiness of the produced ash particles. The melting behavior of the slag generated by the cocombustion tests appeared to be somewhat different compared to that of the laboratory-prepared ash samples. The heated stage XRD data provide useful information regarding the reactions among the various ash compounds and the phase transformations during the heating and cooling of the ash samples and helped the explanation of the produced viscosity curves.

Arvelakis, Stelios; Folkedahl, B.

2006-01-01

302

Rheology of fly ashes from coal and biomass co-combustion  

DEFF Research Database (Denmark)

The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of various coal/biomass blends in a pilot scale pf-boiler. The produced data provide information on the melting of the ash and its flow characteristics, as a function of temperature, which may be used to modify the temperature profile of the boiler in order to avoid slagging. Straw co-firing lowers the ash viscosity leading to higher stickiness of the ash particles. Wood co-firing has only minor effects, due to the composition of wood ash and the low percentage of wood in the coal/biomass blend.

Arvelakis, Stelios; Frandsen, Flemming

2010-01-01

303

Physico-chemical characterization and leaching of desulphurization coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Fly ash produced by coal combustion using two types of desulphurization process were studied: a conventional pulverized coal boiler equipped with lime injection (PCL ash), and a circulating fluidized bed combustion boiler with limestone injection (CFBC ash). The ashes were characterized completely: granulometry, morphology, mineralogy, chemical composition and behaviour to water contact. Both PCL ash and CFBC ash present similar features: fine granulometry, presence of anhydrite phase and sulphate content. However, PCL ash also shows lots of spherical particles, unlike CFBC ash, and a much higher lime content, due to the lower desulphurization rate in PC boilers. Unlike CFBC ash, most of the trace elements in PCL ash show an inverse concentration-particle size dependence. Leachates obtained from both samples are rich in soluble salts (CaSO{sub 4} and Ca(OH){sub 2}) and arsenic and selenium are prevented from solubilizing by high lime content. In wetted PCL ash, the formation of ettringite crystals stabilizes calcium and sulphur ions. Simultaneously, arsenate, selenate and chromate anions are trapped in the crystal. CFBC ash does not really harden because the lime content is too low. However, the leached selenium concentration is cut down in wetted CFBC ash samples.

Lecuyer, I.; Bicocchi, S.; Ausset, P.; Lefevre, R. [Electricite de France, Chatou (France). Direction des Etudes et Recherches

1996-02-01

304

Determination physico-chemical properties of fly ash and pond ash of Talcher thermal power plant for stowing in the underground coal mines  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the outcome of the experimental work carried out for the characterization of fly ash and pond ash samples collected from Talcher thermal power station (TTPS) in India to evaluate their suitability as stowing material to be used in the early underground coal mine. After studying their characteristics it was found that both the fly ash and pond ash of TTPS are suitable for stowing in the underground coal mines. However, pond ash is a better stowing material than fly ash. 14 refs., 6 tabs.

Das, S.K.; Mishra, D.P. [Indian Institute of Technology, Kharagpur (India)

2008-07-01

305

Coal-fueled fluidized bed boiler. Part 1: New technologies for the use of coal and coal ashes  

Energy Technology Data Exchange (ETDEWEB)

In a series of three articles the new coal-fueled fluidized bed installation of Akzo will be introduced. This first article deals with the technological developments insofar they are related to the Akzo fluidized bed boiler. The use of coal in furnaces, dryers and industrial steam boilers is discussed. A demonstration installation to investigate fluidized bed technology was developed by TNO (Dutch Organization for Applied Scientific Research) and built by Stork Boilers. A measurement program was set up by Stork Boilers and Akzo. Possibilities to lower NO/sub x/ emission are mentioned. Possibilities and accompanying risks to applicate coal ashes are discussed. 2 figs., 6 refs.

Stork, J.

1988-10-01

306

Coal ash fusion temperatures -- New characterization techniques, and associations with phase equilibria  

Energy Technology Data Exchange (ETDEWEB)

The well-documented shortcomings of the standard technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined with laboratory ash prepared at about 800 C in crucibles, as well as combustion ash sampled from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of peaks in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash.

Wall, T.F.; Gupta, R.P.; Gupta, S. [Univ. of Newcastle, New South Wales (Australia). Dept. of Chemical Engineering; Creelman, R.A. [R.A. Creelman and Associates, Epping, New South Wales (Australia); Coin, C. [ACIRL Ipswich, Booval, Queensland (Australia); Lowe, A. [Pacific Power, Sydney, New South Wales (Australia)

1996-12-31

307

Thermogravimetric investigation on co-combustion characteristics of tobacco residue and high-ash anthracite coal.  

UK PubMed Central (United Kingdom)

The thermal behavior of high-ash anthracite coal, tobacco residue and their blends during combustion processes was investigated by means of thermogravimetric analysis (20 K min(-1), ranging from ambient temperature to 1273 K). Effects of the mixed proportion between coal and tobacco residue on the combustion process, ignition and burnout characteristics were also studied. The results indicated that the combustion of tobacco residue was controlled by the emission of volatile matter; the regions were more complex for tobacco residue (four peaks) than for coal (two peaks). Also, the blends had integrative thermal profiles that reflected both tobacco residue and coal. The incorporation of tobacco residue could improve the combustion characteristics of high-ash anthracite coal, especially the ignition and burnout characteristics comparing with the separate burning of tobacco residue and coal. It was feasible to use the co-combustion of tobacco residue and high-ash anthracite coal as fuel.

Li XG; Lv Y; Ma BG; Jian SW; Tan HB

2011-10-01

308

Comparison of fly ash properties from Afsin-Elbistan coal basin, Turkey  

International Nuclear Information System (INIS)

Afsin-Elbistan (AE) coal fly ashes obtained by burning coal samples from top, middle and bottom sections of the AE coal seam were characterized and their properties were compared. Chemical analysis of the AE coal fly ashes showed that they are mainly composed of CaO, SiO2, Fe2O3 and Al2O3. Quantitative X-ray diffraction (XRD) analyses were carried out using an interactive data processing system (SIROQUANTTM) based on Rietveld interpretation methods. Lime is found in all the samples, ranging from around 7% to just over 38%. Amorphous contents of fly ashes are ranged between 19% and 25%. Different types of AE fly ashes revealed that bottom section coal fly ash is very similar to Class F, while medium and top section coal fly ashes are close to Class C and they might be used as mineral admixture in concrete. But also they do not comply with any of the standard. The results presented here show new possibilities for AE coal fly ashes in a wide range of fields, resulting in great advantages in waste minimization, as well as, resources conservation.

2005-03-17

309

Design and construction of gamma transmission gauge for determination of the ash content in coal  

International Nuclear Information System (INIS)

More than two years research work on design of a dual energy ?-ray transmission gauge is reviewed in this paper. The gauge after construction will be to install in a large coal industry named Kerman District Coal Mines (KDCM). KDCM consists of several coal mines, so that, coal transported on a conveyor belt may be a non-homogenious mixture from one or more mines. Therefore, prior to gauge design, primary investigation is done to identify and evaluate the relationship between the mass absorption coefficient (?-bar) and ash percent of coal for the mixture running on the belt. Results of investigation shows that, coal mixture calibration curve cannot be used accurately for ash estimation in coal of individual mines and, essentially, gauge may work to determine the ash percent with some limitations in this particular region. Therefore, design of gauge was carried out in the laboratory and after setting up, primary experimental calibration curve for the gauge is obtained. The r.m.s. difference between gauge ash and chemical assay is 1.17 wt% ash, for ash in the range of 32-44 (wt%). It is programmed for future to complete and improve the gauge to be able for on-line ash determinations. (author). 5 refs, 7 figs, 2 tabs.

1995-01-01

310

Reduction of metal leaching in brown coal fly ash using geopolymers.  

Science.gov (United States)

Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates. Fourteen metals and heavy metals were targeted during the leaching tests and the results indicate that a geopolymer is effective at reducing the leach rates of many metals from the fly ash, such as calcium, arsenic, selenium, strontium and barium. The major element leachate concentrations obtained from leached fly ash were in general lower than that of precipitator fly ash. Conversely, heavy metal leachate concentrations were lower in precipitator fly ash than leached pond fly ash. The maximum addition of fly ash to this geopolymer was found to be 60wt% for fly ash obtained from the electrostatic precipitators and 70wt% for fly ash obtained from ash disposal ponds. The formation of geopolymer in the presence of fly ash was studied using 29Si MAS-NMR and showed that a geopolymer matrix was formed. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) imaging showed the interaction of the fly ash with the geopolymer, which was related to the leachate data and also the maximum percentage fly ash addition. PMID:15511575

Bankowski, P; Zou, L; Hodges, R

2004-10-18

311

Employing support vector machine to predict the ash fusion temperature of coal blends  

Energy Technology Data Exchange (ETDEWEB)

In order to improve the accuracy of the prediction of ash fusion temperature, a support vector machine and genetic algorithms were combined to model the ash fusion temperature of coal blends. The chemical composition of the coal ash were employed as inputs and the ash fusion temperature as output. The results show that the maximum and average relative predicting errors are 7.4 and 0.678%. The support vector machine can find its application in small sample training. Its calculating speed is fast which can improve the real-time processing performance. 10 refs., 2 figs., 1 tab.

Li, J.; Zhou, H.; Wang, C.; Cen, K. [Zhejiang University, Hangzhou (China)

2007-07-01

312

Physical factors affecting the mutagenicity of fly ash from a coal-fired power plant.  

UK PubMed Central (United Kingdom)

The two finest, most respirable coal fly ash fractions collected from the smokestack of a power plant were more mutagenic than two coarser fractions. Mutagenicity was evaluated in the histidine-requiring bacterial strains TA 1538, TA 98, and TA 100 of Salmonella typhimurium. Ash samples collected from the hoppers of an electrostatic precipitator in the plant were not mutagenic. The mutagens in coal fly ash were resistant to x-ray or ultraviolet irradiation, possibly as a result of stabilization by fly ash surfaces. All mutagenic activity is lost with heating to 350 degrees C.

Fisher GL; Chrisp CE; Raabe OG

1979-05-01

313

Quantum chemistry calculation and experimental study on coal ash fusion characteristics of coal blend  

Energy Technology Data Exchange (ETDEWEB)

The coal ash fusion characteristics of high fusibility coal blending with two low fusibility coals respectively were studied. The data were analyzed using quantum chemistry methods and experiment from micro-and macro-molecular structures. The results show that Ca{sup 2+}, as the electron acceptor, easily enters into the lattice of mullite, causing a transition from mullite to anorthite. Mullite is much more stable than anorthite. Ca{sup 2+} of anorthite occupies the larger cavities with the (SiO{sub 4}){sup 4-} tetrahedral or (AlO{sub 4}){sup 5-} tetrahedral rings respectively. Ca atom linked O weakens Si-O bond, leading ash fusion point to reduce effectively. The chemistry, reactivity sites and bond-formation characteristics of minerals can well explain the reaction mechanism refractory minerals and flux ash melting process at high temperature. The results of experiment are agreed with the theory analysis by using ternary phase diagrams and quantitative calculation. 27 refs., 9 figs., 3 tabs.

Chen Yushuang; Zhang Zhong-xiao; Wu Xiao-jiang; Li Jie; Guang Rong-qing; Yan Bo [University of Shanghai for Science and Technology, Shanghai (China). Department of Power Engineering

2009-07-01

314

Fly ash development from sodium, sulphur and silica during coal combustion  

Energy Technology Data Exchange (ETDEWEB)

A synthetic coal was made from a furfuryl alcohol polymer with appropriate amounts of sodium, sulphur and silica to duplicate the characteristics of a low rank coal. The synthetic coal was burned in a laminar flow (drop-tube) furnace at 900, 1100, 1300 and 1500{degree}C. The resulting fly ash particles were quickly quenched, collected and analysed using a scanning electron microscope to determine size and composition. Below 1100{degree}C, fly ash formation was dominated by coalescence of the mineral matter in the burning particle to form close to one fly ash particle per original coal particle. At higher temperatures, fly ash formation was dominated by fragmentation of the coal/char particle followed by coalescence within the resulting fragments. At the lower temperatures, submicrometre sodium sulphate particles were found adhered to the larger sodium-rich silicate particles. At higher temperatures, the abundance and size of the sodium sulphate particles decreased. 11 refs., 7 figs., 1 tab.

Erickson, T.A.; Ludlow, D.K.; Benson, S.A. (University of North Dakota, Grand Forks, ND (USA). Energy and Environmental Research Center)

1991-01-01

315

Application of dry separative methods for decreasing content the residues unburned coal and separation Fe from black coal flies ash  

Directory of Open Access Journals (Sweden)

Full Text Available Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss onignition - LOI. In present, the valid STN and EU standard limits the content of LOI to 3 – 5 %, in national conditions maximum 7 %.Application of processing technologies also has to assure utilization of fly ash that provides a possibility of complex utilizationof individual products obtained by modification.By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburnedcoal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOIof dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conductingproduct contained 7,72 % of LOI at 73 % of weight yield.

Vladimír Bláha; František Ka?avský

2008-01-01

316

Behaviour of coal mineral matter in sintering and slagging of ash during the gasification process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mineral matter in typical feed coals used in South African gasification processes and the ash derived from gasifying such coals have been investigated using a variety of mineralogical, chemical and electron microscope techniques. The mineral matter in the feed coals consists mainly of kaolinite,...

Matjie, Ratale Henry; French, David; Ward, Colin R.; Pistorius, Petrus Christiaan; Li, Zhongsheng

317

Beneficial use of coal ash in anthracite and bituminous mine reclamation and mine drainage pollution abatement in Pennsylvania  

Energy Technology Data Exchange (ETDEWEB)

The Beneficial Use of Coal Ash has become a common practice in recent years throughout Pennsylvania. Coal ash that was primarily landfilled or dumped on waste piles has now become a viable product for mine reclamation, mine drainage pollution abatement and control, structural fill, construction related products, and various other projects. The promulgation of new residual waste regulations by the Pennsylvania Department of Environmental Protection (DEP) has been one of the main reasons for some of the new coal ash uses, but the utilization of fluidized bed combustion by power plants has also been a significant factor in the development of new beneficial uses for coal ash. Although most coal ash can be utilized for some sort of beneficial use, not all coal ash meets regulatory requirements for beneficial use. For a coal ash to be utilized beneficially it must first meet several regulatory guidelines, parameters and requirements. These regulatory guidelines, parameters and requirements address the chemical and physical properties of the coal ash, and these properties as well as the type of coal or coal refuse being burned, help determine how a specific coal ash can be utilized beneficially. The current beneficial uses of coal ash are consistently being utilized to help solve environmental and safety related problems, and future beneficial uses are being developed for even more environmental and safety related projects. All of these beneficial uses open up significant landfill space, reduce power plant and electrical related production costs; while helping reclaim and correct environmental and safety related problems.

Scheetz, B.E. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.; Menghini, M.J.; Hornberger, R.J.; Owen, T.D. [Pennsylvania Dept. of Environmental Protection, Pottsville, PA (United States). District Mining Operations; Schueck, J. [Pennsylvania Dept. of Environmental Protection, Harrisburg, PA (United States). Bureau of Mining and Reclamation

1997-12-31

318

Main characteristics of the radioactive enrichment in ashes produced in coal-fired power stations  

International Nuclear Information System (INIS)

[en] Under contract with the Spain's 'Nuclear Safety Council', a study is being conducted of the nation's largest nominal output coal-fired power stations. Its purpose is to assess the radiological impact on workers and local populations due to this source of NORM activity. One of the aspects of particular interest is the study of the radioactive enrichment in the combustion wastes relative to the different coals used as fuel (usually local bituminous coal or lignite, or imported coal). These wastes consist of fly ash (mostly fine particles collected in electrostatic precipitators), and bottom ash (larger in size, and collected wet or dry in hoppers below the boilers). In general terms, the enrichment factors measured were between 2 and 18 for the radionuclides 40K, 226Ra, 232Th, and 210Po. The magnitude of this enrichment factor depended mainly on the ash content of each coal, and hence on the type of coal used as fuel and the specific operation cycle in the different power stations. For the radionuclides 40K, 226Ra, and 232Th, the enrichment was relatively similar in value in the fly and bottom ashes produced by the different types of coal used in the power stations studied. For 210Po, however, as was expected, the enrichment was much greater in the fly ash than in the bottom ash for each coal analyzed. (author)

2008-01-01

319

Uranium content of coal ashes from Southern Brazil coal fueled power stations, by the fission track registration technique  

International Nuclear Information System (INIS)

[en] The feasibility of the application of the fission track registration technique for the determination of uranium in coal ashes was shown. The wet method was employed using as detector the Makrofol KG=10 ?m, manufactured by Bayer. The coal ashes were originated from coal-fueled power stations localized in Southern Brazil. The results obtained ranged from 10 to 27 mg U/kg. Since the total error variation was from 18,4% to 23,8%, the method used was considered excellent. The determination of the uranium content in coal ashes is of considerable interest in environmental control in power stations, in their vicinity and wherever these ashes are used or stored. The technique used is the work proved to be very appropriate for the purpose aimed at. (Author)

1981-01-01

320

Densification, shrinkage and strength development in selected coal ashes  

Energy Technology Data Exchange (ETDEWEB)

The densification process was measured in four amorphous coal ashes, as a function of temperature at constant time and as a function of time at constant temperature. Densification increased significantly if samples were sintered above the characteristic temperature {Tau}{sub cr}. Above that temperature the sintering process is governed by the shrinkage of pores and the flow of melts out of the inter-granular spaces into the large and small pores. The characteristic temperature of sintering is defined as the temperature at which the sintering mechanism changes from the formation of necks and pores into pore-shrinkage and pore-filling by melt, which corresponds to low-strength deposits that respond to the pressure created by soot-blowing. 14 refs., 4 figs., 1 tab.

Nowok, J. [University of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center

1996-03-01

 
 
 
 
321

Floating cultivation of marine cyanobacteria using coal fly ash.  

UK PubMed Central (United Kingdom)

The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine micro-algae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0 x 10(8) cells/cm2 was achieved using seawater. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

Matsumoto M; Yoshida E; Takeyama H; Matsunaga T

2000-01-01

322

Determination of selenium species in coal fly ash extracts  

Energy Technology Data Exchange (ETDEWEB)

An ion chromatography method was developed to determine selenite and selenate in the presence of other common anions in extracts from coal fly ash samples. The anions were separated using a Dionex AG5 guard column and an AS4A separator column and then quantified using conductivity detection. The eluant consisted of 2.0 mM sodium carbonate and 1.0 mM sodium hydroxide. This method separates selenite and selenate without interference problems from nitrate, phosphate, and sulfate. The detection limits for selenite and selenate were 0.05 mg/L using a 50-[mu]L sample injection loop and a detector setting of 1 [mu]S full scale. The selenium concentrations detected using ion chromatography were compared to total selenium values obtained on the same leachates using inductively coupled plasma spectroscopy (ICP) analysis. All the leachates analyzed displayed good agreement between IC and ICP values. 7 refs., 1 fig., 3 tabs.

Niss, N.D.; Schabron, J.F.; Brown, T.H. (Western Research Institute, Laramie, WY (USA))

1993-05-01

323

To the method of increasing accuracy of radioisotope analysis of coal ash content  

International Nuclear Information System (INIS)

[en] The method of accuracy increase in radioisotopic analysis of coal ash content, which eliminates destabilizing effect of instability of element composition of coal ash, mainly iron and calcium, is suggested. The method consists in recording not only the dispersed constituent of the spectrum of secondary gamma radiation of iron 55 but in calcium fluorescent radiation (approximately 3.7 keV). Mean quadratic deviation of the method results from the data of chemical analysis constituted 0.32% at Ca amount variation of 2-12% and coal ash content 8-12%

1980-01-01

324

Removal rate of zinc from coal bottom ash in aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

The leaching of inorganics including heavy metals from coal ashes has recently received much attention. This study was undertaken in order to understand the rate of leaching of metals from coal ash and the significant factors affecting the rate, and to develop an approach to predict leaching rates. The rate of leaching of Zn was characterised quantitatively for one coal bottom ash using a pseudo-kinetic mechanism. The resulting rate constants were correlated over a pH range of 1.3 - 9.3.

Roth, J.A.

1983-01-01

325

Hazards from radioactivity of fly ash of Greek coal power plants (CPP)  

International Nuclear Information System (INIS)

[en] Fly ash and fine dispersion releases from coal combustion in Greek coal power plants were studied. Concentrations in the fly ash up to 20 pCi/g and 10 pCi/g were measured for 238U and 226Ra respectively (not in secular equilibrium). Risk from the fly ash derives from its escape in particulate form or fine dispersion and from its use as a substitute for cement in concrete. The new data indicate that coal power plants discharge relatively larger quantities of radioactive material into the atmosphere than nuclear power plants of comparable size, during normal operation. (H.K.)

1980-03-14

326

Optimum ash content of coal charge for the Yasinovka coking plant with different contents of Karaganda coals  

Energy Technology Data Exchange (ETDEWEB)

Karaganda coal is high in ash compared with analogous Donbass coals, so that blend ratios had to be adjusted at Yasinovka to ensure economic coke making. The optimum ash content was determined as 6.8%, and it was necessary to restrict the proportion of Karaganda coal to maintain this figure. Washery jigs had to be adjusted when Karaganda coal was included in the charge, reducing the cut-point from 1.60 1.63 g/cm/SUP/3 to 1.54-1.55 g/cm/SUP/3.

Zhidko, A.S.; Belov, K.A.; Maksimova, M.I.; Trofimova, V.G.; Beizer, V.N.; Litmanovich, I.M.; Statsenko, V.M.

1981-09-01

327

Ash handling systems for coal fired power stations; Sekitan karyoku hatsudensho no haishori gijutsu ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

This paper outlines the latest trends in ash handling systems for coal fired power stations and the Kawasaki`s new technology. In the current ash handling system, the amount of ash to be handled has been increasing and the ash handling systems have been dispersed for arrangement. The ash handling systems must be arranged in cooperation with other facilities and must satisfy the recycle law and operating environmental conditions. Moreover, the outline of ash handling systems (ash conveying equipment, ash storing equipment, and equipment for ash`s final handling) is described. Next, the clinker handling equipment in which a clinker hopper and jet pulsion pump were combined and the fly ash handling equipment based on a low-density pneumatic transportation system are given as an example. Many of the handling equipment above have been delivered by Kawasaki. Clinker transportation technology (Magaldi ash conveyor, submerged chain conveyor, and clinker transportation slurry pump) and fly ash transportation technology (flow dynamic conveyor and reclamation system for fly ash in high-density slurry) are introduced as new technology. 3 refs., 6 figs., 1 tab.

Takahashi, Y. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1996-07-20

328

Prediction of Chinese coal ash fusion temperatures in Ar and H{sub 2} atmospheres  

Energy Technology Data Exchange (ETDEWEB)

The ash fusion temperatures (AFTs) of 21 typical Chinese coal ash samples and 60 synthetic ash samples were measured in Ar and H{sub 2} atmospheres. The computer software package FactSage was used to calculate the temperatures corresponding to different proportions of the liquid phase and predict the phase equilibria of synthetic ash samples. Empirical liquidus models were derived to correlate the AFTs under both Ar and H{sub 2} atmospheres of 60 synthetic ash samples, with their liquidus temperatures calculated by FactSage. These models were used to predict the AFTs of 21 Chinese coal ash samples in Ar and H{sub 2} atmospheres, and then the AFT differences between the atmospheres were analyzed. The results show that, for both atmospheres, there was an apparently linear correlation and good agreement between the AFTs of synthetic ash samples and the liquidus temperatures calculated by FactSage (R > 0.89, and {sigma} < 30{sup o}C). These models predict the AFTs of coal ash samples with a high level of accuracy (SE < 30{sup o}C). Because the iron oxides in coal ash samples fused under a H{sub 2} atmosphere are reduced to metallic iron and lead to changes of mineral species and micromorphology, the AFTs in a H{sub 2} atmosphere are always higher than those with an Ar atmosphere. 34 refs., 9 figs., 7 tabs.

Wen J. Song; Li H. Tang; Xue D. Zhu; Yong Q. Wu; Zi B. Zhu; Shuntarou Koyama [East China University of Science and Technology, Shanghai (China)

2009-04-15

329

Characteristics of emitted fly ash and trace elements from utility boilers fired with pulverized coal  

Energy Technology Data Exchange (ETDEWEB)

For the generation of electricity, coal becomes increasingly more important as a substitute for fuel oil. One of the consequences is an increase in the emission of fly ash and volatile (trace) particles; this emission has been studied for utility boilers that are fired with pulverized coal. The relevant parameters are (1) the type of boiler, (2) the ash-collection devices employed and (3) the type of coal. The study concerns the distribution of trace particles over the various flows: from coal to furnace-bottom ash, pulverized fuel ashes (PFA) as collected in the successive compartments of the electrostatic precipitator (ESP), and the emitted ash (fly ash). It appears that, at increased particulate loadings in the flue gas after the ESP, the contribution of coarse particles will be larger and hence the enrichment of elements that submit to the vaporization-condensation mechanism, will be lower. There is evidence to show that enrichment cannot only be studied from the fly ash, but also from the trends of trace-elements concentration in the PFA collected in the successive compartments of the ESP. In this study, the volatile elements' concentrations in the fly ash are about twice as high as in the PFA from the last ESP compartment. Therefore, the elemental composition of the PFA collected in the last ESP compartment is indicative of the composition of the emitted fly ash.

Meij, R.; van der Kooij, J.; van der Sluys, J.L.G.; Siepman, F.G.C.; van der Sloot, H.A.

1984-01-01

330

Characteristics of emitted fly ash and trace elements from utility boilers fired with pulverized coal  

Energy Technology Data Exchange (ETDEWEB)

For the generation of electricity, coal becomes increasingly more important as a substitute for fuel oil. One of the consequences is an increase in the emission of fly ash and volatile (trace) particles; this emission has been studied for utility boilers that are fired with pulverized coal. The relevant parameters are: the type of boiler, the ash-collection devices employed, and the type of coal. The study concerns the distribution of trace particles over the various flows: from coal to furnace-bottom ash, pulverized fuel ashes (PFA) as collected in the successive compartments of the electrostatic precipitator (ESP), and the emitted ash (fly ash). It appears that, at increased particulate loadings in the flue gas after the ESP, the contribution of coarse particles will be larger and hence the enrichment of elements that submit to the vaporization-condensation mechanism, will be lower. There is evidence to show that enrichment can not only be studied from the fly ash, but also from the trends of trace-element concentration in the PFA collected in the successive compartments of the ESP. In this study, the volatile elements' concentrations in the fly ash are about twice as high as in the PFA from the last ESP compartment. Therefore, the elemental composition of the PFA collected in the last ESP compartment is indicative of the composition of the emitted fly ash.

Meij, R.; van der Kooij, J.; van der Sluys, J.L.G.; Siepman, F.G.C.; van der Sloot, H.A.

1984-01-01

331

Mercury capture by selected Bulgarian fly ashes: Influence of coal rank and fly ash carbon pore structure on capture efficiency  

Energy Technology Data Exchange (ETDEWEB)

Mercury capture by fly ash C was investigated at five lignite- and subbituminous-coal-burning Bulgarian power plants (Republika, Bobov Dol, Maritza East 2, Maritza East 3, and Sliven). Although the C content of the ashes is low, never exceeding 1.6%, the Hg capture on a unit C basis demonstrates that the low-rank-coal-derived fly ash carbons are more efficient in capturing Hg than fly ash carbons from bituminous-fired power plants. While some low-C and low-Hg fly ashes do not reveal any trends of Hg versus C, the 2nd and, in particular, the 3rd electrostatic precipitator (ESP) rows at the Republika power plant do have sufficient fly ash C range and experience flue gas sufficiently cool to capture measurable amounts of Hg. The Republika 3rd ESP row exhibits an increase in Hg with increasing C, as observed in other power plants, for example, in Kentucky power plants burning Appalachian-sourced bituminous coals. Mercury/C decreases with an increase in fly ash C, suggesting that some of the C is isolated from the flue gas stream and does not contribute to Hg capture. Mercury capture increases with an increase in Brunauer-Emmett-Teller (BET) surface area and micropore surface area. The differences in Hg capture between the Bulgarian plants burning low-rank coal and high volatile bituminous-fed Kentucky power plants suggests that the variations in C forms resulting from the combustion of the different ranks also influence the efficiency of Hg capture.

Kostova, I.J.; Hower, J.C.; Mastalerz, M.; Vassilev, S.V. [University of Kentucky, Lexington, KY (United States). Center of Applied Energy Research

2011-01-15

332

Development of high-performance coal gasification technology for high ash fusion point coals by coal blending method. Behavior of coal ash fusion temperature and gasification characteristics; Kontan ni yoru kohaiyutentan koseino gas ka gijutsu no kaihatsu. Haiyuten koka oyobi gas ka kihon tokusei ni kansuru kento  

Energy Technology Data Exchange (ETDEWEB)

In the entrained bed coal gasification method it is necessary to fuse and remove ash in coal, so the higher an ash fusion point of the coal is, the higher a temperature in the coal gasifier should be kept. Therefore, the amount of air into the gasifier is increased. Naturally performance of the gasifier tends to be lowered. At present, about 50% of imported coals for electric power use are high ash fusion point coals. To commercialize this coal gasification method, it is important to develop technology for gasifying high ash fusion point coals at high performance by flux addition, coal blending, etc. This paper studies behaviors of ash fusion point lowering by coal blending using high ash fusion point coal and low ash fusion point coal and basic characteristics of coal blending gasification in a 2T/D coal gasifier. As a result, it is found that it is possible to substantially lower the ash fusion point (approximately 350{degree}C or more) by coal blending. Moreover, from results of the bench-scale gasification in the 2T/D gasifier, it is clarified that slag of high ash fusion point coal is reduced by coal blending, improvement of gasification performance becomes possible by reducing the amount of air into the gasifier, and settlement of the appropriate coal blending ratio improves operational performance. 8 refs., 20 figs., 11 tabs.

Inumaru, J.; Hara, S.; Ashizawa, M.; Hamamatsu, T. [Central Reserach Institute of Electric Power Industry, Tokyo (Japan); Takekawa, T.; Koyama, T. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

1991-02-01

333

Determination of physico-chemical properties of fly ash and pond ash of Talcher thermal power plant for stowing in the underground coal mines  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the outcome of the experimental work carried out for the characterization of fly ash and pond ash samples collected from the Talcher Thermal Power station (TTPS) to evaluate their suitability as stowing material to be used in the nearby underground coal mines. The physical properties like bulk density, specific gravity, particle size analysis, particle morphology, and permeability are determined. The chemical characteristics of the ash samples are studied by using scanning electron microscopy (SEM). Some of the geotechnical properties like compaction and consolidation characteristics of fly ash and pond ash samples are studied. After studying all the foregoing characteristics it is found that both the fly ash and pond ash of TTPS are very much suitable for stowing in the underground coal mines. However, pond ash is a better stowing material as compared to fly ash. 14 figs., 6 tabs.

Das, S.K.; Mishra, D.P. [IIT Kharagpur (India). Dept. of Mining Engineering

2008-07-01

334

Speciation of chromium in feed coals and ash byproducts from Canadian power plants burning subbituminous and bituminous coals  

Energy Technology Data Exchange (ETDEWEB)

The chromium species in the feed coals and ash byproducts from seven Canadian coal-fired power plants were examined using Cr X-ray absorption near-edge spectroscopy. Chromium in the Canadian feed coals is always found as Cr{sup 3+} but generally has a dual occurrence, as Cr{sup 3+} is distributed to varying degrees between the clay mineral illite and a poorly crystallized chromium oxyhydroxide phase associated with the organic fraction. In two subbituminous feed coals from Alberta, chromium is present largely as Cr{sup 3+}/illite, whereas in two other such coals, it is present predominantly as CrOOH. Chromium in a low-sulfur bituminous feed coal from Alberta is found mostly as Cr{sup 3+}/illite, whereas for feed coals from Nova Scotia with high sulfur contents, chromium is distributed between both Cr{sup 3+}/illite and CrOOH. Very little chromium was found in the limestone used in a fluidized-bed combustor. The chromium species in most bottom ash samples from all seven combustion units is predominantly, if not entirely, Cr{sup 3+} associated with aluminosilicate phases. Chromium speciation for subbituminous electrostatic precipitator fly ash is mostly Cr{sup 3+}, but in some cases, it is slightly lessand varies by sampling location at the plant. Chromium in fly ash from the combustion of bituminous feed coals is predominantlyCr{sup 3+}. A unique species of chromium found in one feed coal and an unrelated fly ash is metallic chromium, similar to that in stainless steel. The occurrence of this form of chromium in these materials indicates contamination from machinery, such as the coal milling machine or possibly wearing down of stainless steel parts by the coal or ash. The observation of this unexpected contamination demonstrates the power and usefulness of X-ray absorption fine-structure spectroscopy for speciation determination. 35 refs., 6 figs., 4 tabs.

Fariborz Goodarzi; Frank E. Huggins [Geological Survey of Canada-Calgary Division, Calgary, AB (Canada)

2005-12-01

335

Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review.  

Science.gov (United States)

In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being "a dumping ground for mercury". This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases. PMID:16183102

Mukherjee, Arun B; Zevenhoven, Ron

2005-09-22

336

Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review.  

UK PubMed Central (United Kingdom)

In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being "a dumping ground for mercury". This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases.

Mukherjee AB; Zevenhoven R

2006-09-01

337

Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review  

Energy Technology Data Exchange (ETDEWEB)

In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being 'a dumping ground for mercury'. This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases. (author)

Mukherjee, Arun B. [Department of Biological and Environmental Sciences, Helsinki University, P.O. Box 27, FIN-00014 Helsinki (Finland); Zevenhoven, Ron [Energy Engineering and Environmental Protection, Helsinki University of Technology, P.O. Box 4400, FIN-02015 Espoo (Finland)

2006-09-01

338

Relations between ash-fusion characteristics and depositional environment for an Appalachian Basin coal seam  

International Nuclear Information System (INIS)

This paper reports that ash-fusion characteristics of the Lower Kittanning seam (western Pennsylvania) can be related to environment of deposition. Non-slagging coals (coals with ashes that have ash-fusion temperatures [AFTs] in excess of 2,600 degrees F) are associated with fresh-water environments that occur toward the margins of the basin. Slagging coals (coals with ashes that melt at temperatures less than 2,000 degrees F) occur in the central part of the basin, in areas overlain by shales that have been interpreted to have formed in a brackish environment. Trend-surface analysis indicates that whereas strong basinal trends do exist, locally variability can modify regional trends. High ash-fusion coals are associated with high clay (primarily kaolinite) contents, whereas low-fusion coals are associated with high pyrite and marcasite (and to a lesser extent, siderite) contents. Bivariate analysis of these data shows highly significant negative correlations between AFT and Fe2O3, pyrite, and siderite. Positive correlations exist between AFT and SiO2, Al2O3, TiO2, MgO, and K2O. Illite and kaolinite also correlate positively with AFT. An understanding of the oxide and mineral composition of the ash and the depositional environment of the peat can therefore be useful in the prediction of ash-fusion characteristics

1990-01-01

339

Effects of ash and slag characteristics on the utilisation of Australian coals in IGCC power generation  

Energy Technology Data Exchange (ETDEWEB)

The next generation of coal based power stations, both overseas and in Australia, could well use integrated gasification - combined cycle (IGCC) technology. For bituminous coals, processes based on entrained-flow gasification operated in a slagging mode appear to be of most interest. At the high temperatures prevailing in slagging gasifiers, the total ash content, the ash fusion temperatures, the composition of the ash and the viscosity and crystallisation characteristics of the molten slag, become critical in coal selection. The relatively high ash fusion temperatures of many Australian bituminous coals ({gt}1500{degree}C), are of particular concern and for such coals it will be necessary to add fluxes in order to enable optimum slag tapping. In such cases the type and amount of flux also become important factors in coal selection for IGCC power plants. This paper reviews the coal quality requirements for satisfactory slag tapping. Slag viscosity versus temperature data for selected Australian bituminous coals are compared against these requirements and the use of limestone as the flux examined for a coal with high ash fusion characteristics. 26 refs., 5 figs., 2 tabs.

Patterson, J.H.; Hurst, H.J. [CSIRO, North Ryde, NSW (Australia). Division of Coal and Energy Technology

1994-12-31

340

Determination of ash content of coal on-line on conveyors and in-stream in coal slurries  

International Nuclear Information System (INIS)

[en] Australian work on the determination of ash content of coal on conveyors, based on the combination of measurements of transmission of low- and high-energy ?-rays, is reviewed. Root mean square differences between gauge and chemical assay are 0.3-0.45 wt% for low-ash coal, and usually 0.7-1.5 wt% for as-mined coal of high ash content. The gauges are in routine use in the Australian coal industry. Techniques have been developed for the determination of the solids weight fraction (W) and ash content of coal in slurries of variable voidage. The technique is based on the correlation between solids weight fraction and hydrogen concentration (wt/wt) of the slurry. The technique combines measurements of neutron moderation, ?-ray transmission, X-ray backscatter and iron K X-ray excitation. In laboratory experiments with coal slurries of 5-20 wt% solids, 21-30 wt% ash, and voidage 0-4 vol.%, RMS differences between gauge and conventional assays were 0.54 wt% solids and 0.78 wt% ash. (author)

1986-01-01

 
 
 
 
341

Combined adsorption and oxidation mechanisms of hydrogen sulfide on granulated coal ash.  

UK PubMed Central (United Kingdom)

Hydrogen sulfide is highly toxic to benthic organisms and may cause blue tide with depletion of dissolved oxygen in water column due to its oxidation. The purpose of this study is to reveal the combined adsorption and oxidation mechanisms of hydrogen sulfide on granulated coal ash that is a byproduct from coal electric power stations to apply the material as an adsorbent for hydrogen sulfide in natural fields. Sulfur species were identified in both liquid and solid phases to discuss removal mechanisms of the hydrogen sulfide with the granulated coal ash. Batch experiments revealed that hydrogen sulfide decreased significantly by addition of the granulated coal ash and simultaneously the sulfate ion concentration increased. X-ray absorption fine structure analyses showed hydrogen sulfide was adsorbed onto the granulated coal ash and successively oxidized by manganese oxide (III) contained in the material. The oxidation reaction of hydrogen sulfide was coupling with reduction of manganese oxide. On the other hand, iron containing in the granulated coal ash was not involved in hydrogen sulfide oxidation, because the major species of iron in the granulated coal ash was ferrous iron that is not easily reduced by hydrogen sulfide.

Asaoka S; Hayakawa S; Kim KH; Takeda K; Katayama M; Yamamoto T

2012-07-01

342

Fabrication of Test Tubes for Coal Ash Corrosion Testing  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the fabrication of tube sections of four alloys for incorporating into test sections to be assembled by Babcock & Wilcox (B&W) for installation at Ohio Edison Power, Niles Plant. The primary purpose of the installation was to determine the corrosion behavior of ten different alloys for flue gas corrosion. Ohio Edison Power, Niles Plant is burning an Ohio coal containing approximately 3.4% S (dry basis) and approximately 0.4% alkali which causes chronic coal ash corrosion of the unit?s superheater tubing. The 2.5-in.-OD x 0.4in.-wall x 6-in-long sections of four alloys {type 304H coated with Fe3Al alloy FAS [developed at the Oak Ridge National Laboratory (ORNL)], 310 + Ta, modified 800H, and Thermie alloy} were fabricated at ORNL. Each alloy tubing was characterized in terms of chemical analysis and microstructure. The machined tubes of each of the alloys were inspected and shipped on time for incorporation into the test loop fabricated at B&W. Among the alloys fabricated, Thermie was the hardest to extrude and machine.

Johnson, R.; Judkins, R.R.; Sikka, V.K.; Swindeman, R.W.; Wright, I.G.

1999-05-11

343

Appearance of thermal plasticity with low rank coals by solvent de-ashing  

Energy Technology Data Exchange (ETDEWEB)

This study concerns with the thermal plasticity of 'Hyper-coal' and its applicability for the coke material. Hyper-coal (HPC) is an ashless coal, which is made by applying the solvent de-ashing technology. Coal is extracted with the coal derived recycling solvent, which consists mainly with 2-ring aromatics, at 360-400{sup o}C, and the solid material (Resid coal, RC, insoluble coal including ash) is removed by gravity settling. We can feature the Hyper-coal as an ashless and high heat value ({gt}35 MJ/kg) coal. In addition, we found that Hyper-coal has an excellent thermal plasticity, which is an important characteristic to make a high strength coke for steel producing using blast furnace. Several kinds of bituminous coals, sub-bituminous coals and brown coals were thermally extracted and filtrated in high temperature (250-400{sup o}C). Gieseler plastometer tests were carried out with Hyper-coals. We found that Hyper-coal revealed much more excellent fluidity from lower temperature to higher temperature range than that of the parent coal. Moreover, not only from the coking coal, but also from the low rank coal, which had no thermal plasticity, the produced Hyper-coal revealed an excellent thermal plasticity. In addition, the mixture of HPC and RC also revealed the thermal plasticity, even though the parent coal was brown coal. It is expected that Hyper-coal from low-rank coal will be utilized for a substitute of coking coal or an additive for making high strength coke. 5 refs., 13 figs., 5 tabs.

Noriyuki Okuyama; Atsushi Furuya; Nobuyuki Komatsu; Takuo Shigehisa [Kobe Steel, Ltd., Hyogo (Japan). Coal & Energy Project Dept.

2005-07-01

344

Solvent de-ashing from heavy product of brown coal liquefaction using toluene. 1. Solubility of heavy products and settling velocity of ash  

Energy Technology Data Exchange (ETDEWEB)

The Brown Coal Liquefaction (BCL) process is a two-stage liquefaction (hydrogenation) process developed for Victorian brown coal in Australia. In the BCL process, the heavy product (vacuum residue) derived from the coal in the primary hydrogenation, which is named CLB (coal liquid bottom, boiling point {gt}420{degree}C), is treated in a solvent (CLM/solvent ratio, 1/8-1/4, wt./wt.) under high temperature (200-290{degree}C) and high pressure (4-5 MPa) to remove the ash and heavy preasphaltenes. This solvent de-ashing process uses toluene or coal-derived naphtha as a deashing solvent. After dissolving the CLB into the solvent, insoluble solid particles which consist of the ash and heavy preasphaltenes are settled in a settler by gravity and separated from the solution as an ash-concentrated slurry. The ash-concentrated slurry and the de-ashed solution are withdrawn from the settler as an underflow and overflow, respectively. The de-ashing solvent is recovered from both the overflow and underflow by distillation, and reused in the de-ashing process. The de-ashed heavy product recovered from the solution by eliminating the solvent is further hydrogenated in the secondary hydrogenation. The paper discusses the solubility of the CLB into toluene and settling velocity of the ash under the de-ashing conditions. 28 refs., 14 figs., 4 tabs.

Okuma, O.; Masuda, K.; Okuyama, N.; Hirano, T. [Kobe Steel Ltd., Kobe (Japan). Chemical, Polymer, Bio, Technology Lab.

1997-10-01

345

Adsorption of anionic dyes from aqueous solutions onto coal fly ash and zeolite synthesized from coal fly ash  

International Nuclear Information System (INIS)

Coal fly ash, a waste generated in coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. The fly ash (CL-2) and this synthesized zeolite (ZM-2) that was characterized as hydroxy-sodalite were used as adsorbents for anionic dyes indigo carmine (IC), and reactive orange 16 (RO16) from aqueous solutions. Effects of contact time, initial dye concentration, pH, adsorbent mass, and temperature were evaluated in the adsorption processes. The kinetics studies indicated that the adsorption followed the pseudo-second order kinetics and that surface adsorption and intraparticle diffusion were involved in the adsorption mechanism. The thermodynamics parameters demonstrated that the adsorption was spontaneous for all adsorption processes. The enthalpy data confirmed the endothermic nature for all adsorption processes except for IC/ZM-2 system which was exothermic. The entropy data showed an increased disorder at the solid/solution interface during the adsorption for all systems except for IC/ZM-2 whose negative entropy value indicated a decreased disorder at the interface. The adsorption isotherms were closely fitted to the Langmuir linear equation. The maximum adsorption capacities were 1.48 mg/g for the IC/CL-2 system; 1.13 mg/g for IC/ZM-2; 0.96 mg/g for RO16/CL-2, and 1.14 mg/g for RO16/ZM-2 at room temperature. The desorption study carried out with water, with acid aqueous solutions, and with an alkali aqueous solution showed to be inefficient both for recovering the dyes and regenerating the adsorbents. (author)

2010-01-01

346

Alkaline mine drainage from metal sulphide and coal mines: examples from Svalbard and Siberia  

Energy Technology Data Exchange (ETDEWEB)

This paper presents previously unpublished data from coal mines of the Abakan-Chernogorsk region, Khakassia, Serbia, the coal miens of Longycarbyen, Svalbard, an Arctic archipelago and magnetite mines in the Sayan and Kuznetsk-Alatau Mountains of Siberia to illustrate the chemistry of alkaline mine drainage waters and to discuss the possible mechanisms involved in their generation. 19 refs., 2 figs., 5 tabs.

Banks, D.; Parnachev, V.P.; Frengstad, B. (and others) [Holymoor Consultancy, Chesterfield (United Kingdom)

2002-10-01

347

Tentative mathematical description of the particle size distribution of coal ash  

Energy Technology Data Exchange (ETDEWEB)

An attempt is made to give a mathematical description of the Henry-Reinhardt cumulative float curve by expressing the mass of the floats as a function of the associated floats ash content. This function ceases to be valid for tailings free from middlings. The aim is to obtain a comparable raw material characterisation of coal by standardising the function to a maximum limiting ash content of, for example, 65%, corresponding to a tailings separation of about 2.0 kg/dmEPSILON3 and excluding the pure tailings. The limiting ash content values (separation ash content) are obtained by differentiation of the ash portion with respect to the floats percentage. The ash particle size distribution of a given coal can thus be calculated.

Nehm, G.

1984-08-01

348

Toxicological effects on mice following inhalation exposures to fluidized-bed coal combustor fly ash  

Energy Technology Data Exchange (ETDEWEB)

Toxicological effects of exposure to reaerosolized fly ash from a fluidized-bed coal combustor were evaluated in mice following 500- and 1000-hr inhalation exposures. Alveolar macrophage function, organ histology, and hematopoiesis were assessed following 24-hr/day exposures in two 500-hr experiments. There was little mutagenicity detected by the Ames assay in the samples of the fly ash tested. The chemical characteristics of the fly ash were very similar to those of fly ash produced during conventional coal combustion. However, physical characterization revealed that fluidized-bed combustion fly ash was not fused as is commonly the case in conventionally combusted fly ash, and as a result had a very large surface area. The function of the alveolar macrophages of exposed mice was impaired, and there were significant changes in the histology of the lung, including cellular infiltration and hyperplasia of bronchiolar and alveolar epithelium. These changes are characteristic of pulmonary responses to chronic irritation of the lung.

Kirchner, F.R.; Reilly, C.A. Jr.; Buchholz, D.M.; Pahnke, V.A. Jr.

1983-12-01

349

Surface adhesion of low-rank coal ash: Quarterly report, January 1986-March 1986  

Energy Technology Data Exchange (ETDEWEB)

The percent of ion-exchangeable cations was determined for the San Miguel lignite. The ion-exchanged material was produced by treating the lignite with ammonium acetate solution. The amounts of exchangeable sodium and calcium were found to be 98% and 76%, respectively. The adhesive properties of lignite ash and sub-bituminous ashes were evaluated using the sticking apparatus. ASTM ashes of these coals were suspended on platinum wire and heated in a methane-oxygen flame of adiabatic temperature between 1650/sup 0/ and 1750/sup 0/C. The resultant molten slags were then dropped onto oxidized mild steel and stainless steel surfaces with typical compositions and temperatures corresponding to boiler tubes. The San Miguel and Navajo ashes each formed highly viscous, porous slags which did not wet the steel substrates. Slag viscosity of the low-rank coal ashes may be more important for judging ash sticking tendencies than ASTM ash fusion temperatures. The ash viscosity predicted by empirical composition/viscosity correlations for the tested slags varied by one to two orders of magnitude from ash to ash whereas the ash fusion temperatures were fairly similar. A vertical tube furnace was used to grow deposits using combusted raw and ion-exchanged San Miguel lignite on cooled boiler steel substrates at conditions similar to those in a utility boiler. Strengths of the deposits were measured and correlated with deposit height and temperature. X-ray diffraction analysis was used to determine the crystalline phases present in bulk deposits.

Austin, L.G.; Benson, S.; Conn, R.

1986-08-01

350

Task 5.9 - use of coal ash in recycled plastics and composite materials.  

Science.gov (United States)

The goal of this research project by the Energy & Environmental Research Center (EERC) was to determine the potential for coal ash to serve as a 'functional filler' in plastics and other composite materials, with special emphasis on recycled plastics. The...

D. J. Hassett B. A. Dockter K. E. Eylands D. F. Pflughoeft-Hassett

1995-01-01

351

Coal and coke - Analysis and testing - Higher rank coal ash and coke ash - Major and minor elements - Borate fusion/flame atomic absorption spectrometric method  

Energy Technology Data Exchange (ETDEWEB)

This Standard sets out a method for the determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium, manganese, barium, strontium and zinc in higher rank coal ash and coke ash by flame atomic absorption spectrometry after borate fusion. A spectrophotometric method for the determination of phosphorus and a method for the determination of sulfur are also referenced. This method is suitable for the determination of the above elements (expressed as oxides), in the concentration specified ranges.

NONE

2003-11-14

352

A review of ash in conventional and advanced coal-based power systems  

Energy Technology Data Exchange (ETDEWEB)

Process conditions are briefly described for conventional and advanced power systems. The advanced systems include both combustion and gasification processes. We discuss problems in coal-based power generation systems, including deposition, agglomeration and sintering of bed materials, and ash attack are discussed. We also discuss methods of mitigating ash problems and anticipated changes anticipated in ash use by converting from conventional to advanced systems.

Holcombe, N.T.

1995-12-31

353

A review of ash in conventional and advanced coal-based power systems  

Energy Technology Data Exchange (ETDEWEB)

Process conditions are briefly described for conventional and advanced power systems. The advanced systems include both combustion and gasification processes. The authors discuss problems in coal-based power generation systems, including deposition, agglomeration and sintering of bed materials, and ash attack are discussed. They also discuss methods of mitigating ash problems and anticipated changes anticipated in ash use by converting from conventional to advanced systems.

Holcombe, N.T. [Dept. of Energy, Morgantown, WV (United States). Morgantown Energy Technology Center

1995-12-31

354

Effect of coal ash on growth and metal uptake by some selected ectomycorrhizal fungi in vitro  

Energy Technology Data Exchange (ETDEWEB)

Six isolates of ectomycorrhizal fungi namely, Laccaria fraterna (EM-1083), Pisolithus tinctorius (EM-1081), Pisolithus tinctorius (EM-1290), Pisolithus tinctorius (EM-1293), Scleroderma verucosurn (EM-1283), and Scleroderma cepa (EM-1233), were grown on three variants of coal ash, namely electrostatically precipitated (ESP) ash, pond ash, and bottom ash moistened with Modified Melin-Norkans (MMN) medium in vitro. The colony diameter reflected the growth of the isolates on the coal ash. Metal accumulation in the mycelia was assayed by atomic absorption spectrophotometry. Six metals, namely aluminum, cadmium, chromium, iron, lead, and nickel were selected on the basis of their abundance in coal ash and toxicity potential for the present work. Growth of vegetative mycelium on fly ash variants and metal accumulation data indicated that Pisolithus tinctorius (EM-1290) was the most tolerant among the isolates tested for most of the metals. Since this isolate is known to be mycorrhizal with Eucalyptus, it could be used for the reclamation of coal ash over burdened sites.

Ray, P.; Reddy, U.G.; Lapeyrie, F.; Adholeya, A. [Energy & Resources Institute, New Delhi (India)

2005-07-01

355

Importance of the radiometric ash content determination by means of beta backscattering for coal transformation  

International Nuclear Information System (INIS)

[en] The radiometric method for ash content determination based on beta backscattering has been evaluated from the point of view of quality control and quality assurance in lignite mining and use of lignite. Applying the method, optimum control and distribution to generation of power, briquetting or coal transformation depending on ash content is possible

1986-01-01

356

Task 5.9 use of coal ash in recycled plastics and composite materials. Topical report  

Energy Technology Data Exchange (ETDEWEB)

The goal of this research project by the Energy & Environmental Research Center (EERC) was to determine the potential for coal ash to serve as a {open_quotes}functional filler{close_quotes} in plastics and other composite materials, with special emphasis on recycled plastics. The term functional filler is intended to indicate that the material added to the plastic does more than take up space and extend the use of the polymer. Determining the functional filler potential of ash was not the only intent of this project, since another prime objective was to find a use for materials currently considered waste. The term functional filler also opened a door to the use of cenospheres, which are currently marketed and for which there is sufficient market demand that they do not fit the category of a waste even though they are a product of coal combustion. Cenospheres, hollow spherical ash particles, were selected because of their unique properties. Although they currently have commercial applications, the unique nature of these materials make them an excellent candidate for use as a functional filler in composites. The ability to produce a commercially viable product from waste streams and a recycled material is a positive step toward reducing solid waste. The first task, since there are numerous types of coal ash, was to select suitable ash types for use in this project. Three basic types of material were selected: fly ash, a bottom ash, and a unique form of coal ash known as cenospheres.

Hassett, D.J.; Dockter, B.A.; Eylands, K.E.; Pflughoeft-Hassett, D.F.

1995-11-01

357

Task 5.9 - use of coal ash in recycled plastics and composite materials  

Energy Technology Data Exchange (ETDEWEB)

The goal of this research project by the Energy & Environmental Research Center (EERC) was to determine the potential for coal ash to serve as a {open_quote}functional filler{close_quotes} in plastics and other composite materials, with special emphasis on recycled plastics. The term functional filler is intended to indicate that the material added to the plastic does more than take up space and extend the use of the polymer. Determining the functional filler potential of ash was not the only intent of this project, since another prime objective was to find a use for materials currently considered waste. The term functional filler also opened a door to the use of cenospheres, which are currently marketed and for which there is sufficient market demand that they do not fit the category of a waste even though they are a product of coal combustion. Cenospheres, hollow spherical ash particles, were selected because of their unique properties. Although they currently have commercial applications, the unique nature of these materials make them an excellent candidate for use as a functional filler in composites. The ability to produce a commercially viable product from waste streams and a recycled material is a positive step toward reducing solid waste. The first task, since there are numerous types of coal ash, was to select suitable ash types for use in this project. Three basic types of material were selected: fly ash, a bottom ash, and a unique form of coal ash known as cenospheres.

Hassett, D.J.; Dockter, B.A.; Eylands, K.E.; Pflughoeft-Hassett, D.F.

1995-07-01

358

Rapid determination of coal ash content by means of X-ray fluorescence and scattering  

International Nuclear Information System (INIS)

[en] Determination of the ash content of coal by measuring secondary radiation of samples in three different energy ranges is presented. A simple equipment with proportional counter and a 238Pu source of primary X-rays were used. The experiments were carried out using 72 coal samples from various deposits. A mean standard deviation of about 2.5% of ash content was achieved. (author)

1983-01-01

359

Combustion of coals with high ash fusion temperatures in a cyclone furnace  

Energy Technology Data Exchange (ETDEWEB)

The combustion of coals having high ash fusion temperature was studied experimentally in a horizontal cyclone furnace. The heat release rate, combustion efficiency of the furnace and slagging behaviour were investigated. It was possible to burn Indian coals having a high ash fusion temperature {gt} 1400{degree}C. The performance of the combustor is reported from a combustion view-point only. No studies were made concerning wear or durability of refractory nozzle. 22 refs., 7 figs., 3 tabs.

Parida, A.; Khuntia, S.; Murty, J.S. (Regional Research Laboratory, Bhubaneswar (India))

1990-11-01

360

Characterization of fly ashes from circulating fluidized bed combustion (CFBC) boilers cofiring coal and petroleum coke  

Energy Technology Data Exchange (ETDEWEB)

The chemistry, mineralogy, morphology, and particle size distribution were investigated in fly ashes from the burning of Datong (ShanXi, China) bituminous coal and the cofiring of Mideast high-sulfur petroleum coke (PC) with 30:70 (cal %) and 50:50 (cal %) blends of Datong bituminous coal in two commercial CFBC boilers. With the exception of CaO, the amounts of major oxides in the fly ashes from cofiring PC and coal were close to those of the common coal fly ashes. The PC-coal fly ashes were enriched in Ni, V, and Mo, implying these trace elements were mainly derived from PC. Ni and V, along with several other elements, such as Cr, Cu, Se, Pb, U, Th, and possibly As and Cd, increased in content with a decrease in temperature of the electrostatic precipitator (ESP). The results of chemistry, mineralogy, and morphology studies suggested that the desulfurization rate of the CFBC boilers at current conditions was low, and the PC tends to coarsen the fly ash particles and increase the loss on ignition (LOI) values, making these fly ashes unsuitable for use as a cement additive or a mineral admixture in concrete. Further studies on the combustion status of the CFBC boilers are needed if we want to be able to increase the desulfurization rate and produce high-quality fly ashes for broader and full utilization. 22 refs., 4 figs., 4 tabs.

Feihu Li; Jianping Zhai; Xiaoru Fu; Guanghong Sheng [Nanjing University, Nanjing (China). State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment

2006-08-15

 
 
 
 
361

The emission of fly ash and trace species from pulverized coal fired utility boilers  

Energy Technology Data Exchange (ETDEWEB)

The emission of fly ash and volatile (trace) species from pulverized coal fired utility boilers has been studied. Relevant parameters are type of boiler, the ash collection devices employed and type of coal. The study concerns the distribution of trace species over the various flows: from coal to furnace bottom ash, pulverized fuel ashes (PFA), as collected in the successive compartments of the electrostatic precipitator (ESP), and the emitted ash, the so-called fly ash. It appears that at increased particulate loadings in the flue gas after the ESP the contribution of coarse particles will be larger and hence the enrichment of elements, which submit to vaporization-condensation mechanism, will be lower. Evidence is presented that enrichment cannot only be studied from the fly ash, but also from the trends of trace element concentration in the PFA collected in the successive compartments of the ESP. In this study for the volatile elements the concentrations in the fly ash are about twice as high as in the PFA from the last ESP compartment. Therefore the elemental composition of the PFA collected in the last ESP compartment is indicative for the composition of the (emitted) fly ash.

Meij, R.; Van der Kooij, J.; Van der Sluys, J.L.G.; Siepman, F.G.C.; Van der Sloot, H.A.

1983-01-01

362

Emission of fly ash and trace species from pulverized coal fired utility boilers  

Energy Technology Data Exchange (ETDEWEB)

The emission of fly ash and volatile (trace) species from pulverized coal fired utility boilers has been studied. Relevant parameters are type of boiler, the ash collection devices employed and type of coal. The study concerns the distribution of trace species over the various flows: from coal to furnace bottom ash, pulverized fuel ashes (PFA), as collected in the successive compartments of the electrostatic precipitator (ESP), and the emitted ash, the so-called fly ash. It appears that at increased particulate loadings in the flue gas after the ESP the contribution of coarse particles will be larger and hence the enrichment of elements, which submit to vaporization-condensation mechanism, will be lower. Evidence is presented that enrichment can, not only be studied from the fly ash, but also from the trends of trace element concentration in the PFA collected in the successive compartments of the ESP. In this study for the volatile elements the concentrations in the fly ash are about twice as high as in the PFA from the last ESP compartment. Therefore the elemental composition of the PFA collected in the last ESP compartment is indicative for the composition of the (emitted) fly ash.

Meij, R.; Van der Kooij, J.; Van der Sluys, J.L.G.; Siepman, F.G.C.; Van der Sloot, H.A.

1983-01-01

363

Coal ash fusion temperatures - new characterization techniques and implications for slagging and fouling  

Energy Technology Data Exchange (ETDEWEB)

The ash fusion test (AFT) is the accepted test for the propensity of coal ash to slag in the furnace. The well-documented shortcomings of this technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined here with laboratory ash prepared at about 800{degree}C in crucibles, as well as combustion ash samples from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of `peaks` in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash. A preliminary evaluation of data from nine power stations indicates that shrinkage measurements can provide an alternative approach to characterizing slagging. 15 refs., 9 figs., 2 tabs.

Wall, T.F.; Creelman, R.A.; Gupta, R.P.; Gupta, S.K.; Coin, C.; Lowe, A. [University of Newcastle, Newcastle, NSW (Australia). CRC for Black Coal Utilisation

1998-09-01

364

Development of high-performance coal gasification technology for high ash fusion coals. Study on determination method of flux adding rate and coal blending ratio  

Energy Technology Data Exchange (ETDEWEB)

Coal gasification performance of the entrained-flow coal gasifiers tend to be the lower for coal with higher ash fusion temperature because of the higher air ratio required to evaluate the combustor gas temperature in order to get the stable slag discharging state. Addition of flux and blending of coals with different characters, known effective to reduce the ash fusion temperature, have been investigated with a gasification test facility (2 t/d Process Development Unit) to confirm them in actual gasifiers. This paper reports the proposition of a correlation to predict the ash fluid temperature on the ash acid rate and presents a procedure to decide the suitable rate of flux addition and coal blending. This report also presents the proper selection guidelines of these methods based on the difference in the effects on gasification performance improvements when these methods are applied.

Ashizawa, M.; Inumara, J.; Hara, S.; Ichikawa, K.; Takahashi, T.; Hamamatsu, T. [Central Research Institute of Electric Power Industry, Yokosuka (Japan). Yokosuka Research Lab., Dept. of Thermal Engineering

1997-12-31

365

Development of bricks with incorporation of coal ash and sludge from water treatment plant  

International Nuclear Information System (INIS)

Sludge from treatment water Brazilian plant station are, frequently, disposed and launched directly in the water bodies, causing a negative impact in the environment. Also, coal ashes is produced by burning of coal in coal-fired power stations and is the industrial solid waste most generated in southern Brazil: approximately 4 million tons/y. The efficient disposal of coal ashes is an issue due to its massive volume and harmful risks to the environment. The aim of this work was study the feasibility of incorporating these two industrial wastes in a mass used in the manufacture of ecological bricks. Samples of fly ashes from a cyclone filter from a coal-fired power plant located at Figueira County in Parana State, Brazil and waterworks sludge of Terra Preta County in Sao Paulo State, Brazil, were used in the study. Fly ash-sludge and fly ash-sludge-soil-cement bricks were molded and tested, according to the Brazilians Standards. The materials were characterized by physical-chemical analysis, X-ray diffraction, thermal analysis, morphological analysis, Fourier transform infrared spectroscopy and granulometric analysis. The results indicate that the waterworks sludge and coal ashes have potential to be used on manufacturing soil-cement pressed bricks according to the of Brazilians Standards NBR 10836/94. (author)

2011-01-01

366

Predicting coal ash fusion temperature based on its chemical composition using ACO-BP neural network  

International Nuclear Information System (INIS)

Coal ash fusion temperature is important to boiler designers and operators of power plants. Fusion temperature is determined by the chemical composition of coal ash, however, their relationships are not precisely known. A novel neural network, ACO-BP neural network, is used to model coal ash fusion temperature based on its chemical composition. Ant colony optimization (ACO) is an ecological system algorithm, which draws its inspiration from the foraging behavior of real ants. A three-layer network is designed with 10 hidden nodes. The oxide contents consist of the inputs of the network and the fusion temperature is the output. Data on 80 typical Chinese coal ash samples were used for training and testing. Results show that ACO-BP neural network can obtain better performance compared with empirical formulas and BP neural network. The well-trained neural network can be used as a useful tool to predict coal ash fusion temperature according to the oxide contents of the coal ash.

2007-02-15

367

MULTISTAGE CAUSTIC LEACHING DE-ASHING OF NIGERIAN LAFIA-OBI COAL  

Directory of Open Access Journals (Sweden)

Full Text Available Fractions of the high ash Nigerian Lafia-Obi coal L±250 ground to pass the 250 ?m sieve in threestages were subjected to proximate/ash composition analyses, hot aqueous leaching de-ashingwith water and sodium carbonate in multiple stages and in a H2O-Na2CO3-H2O sequence (withinitial solution homogenization). The results obtained showed that ash contents percent of 24.60,14.70 and 24.07 were obtained for fractions L-250(1), L-250(2) and L+250(2); respectively asagainst 32.55% in the as-received coal. The ash reductions obtained translate to overall averageash removal of about 38.66% at the 19.90% ash content of the concentrates blend at a good 1:20ratio of reagent to coal. The study also showed that a three stage leaching in the sequence H2ONa2CO3-H2O (HSH) produced a higher leaching rate than Na2CO3-H2O-H2O (SHH). The ash contentof the concentrates blend at 19.90% is lower than 23.80% required for coal blends for Indianstandard coking practice, but higher than the maximum of 10% upper limit for the conventionalcokemaking practice. The reduction in ash content obtained at the atmospheric pressure treatmentof Lafia-Obi coal was found to compare favourably with that of a high pressure elevated temperatureautoclave leaching of an Illinois coal. Binary blend formulation between the prime coking westernCanada coal and Lafia-Obi coal as-leached showed that inclusion of 16.63% of the latter wasprobable and this translates to reduction in cost per ton of about $23.67. A successful upgrade ofthe leaching route derived to industrial scale will make Lafia-Obi coal available as a blend componentfor economical cokemaking.

A. A. Adeleke; S. A. Ibitoye; A. A. Afonja; M. M. Chagga

2011-01-01

368

EFFECT OF COAL ASH ON THE MORPHOLOGICAL, THERMAL AND MECHANICAL PROPERTIES OF POLY(METHYL METHACRYLATE)  

Directory of Open Access Journals (Sweden)

Full Text Available Composite materials of Coal ash/ Poly(Methyl Methacrylate) (ash/PMMA) were prepared/synthesized and their properties were studied by scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA) and universal testing machine (UTM). The morphological study presented that the ash particles were well dispersed and embedded within the PMMA matrix. The DSC thermograms showed that the melting temperature (Tm) of pure PMMA is about 166 ºC which was shifted towards lower temperature when ash were incorporated in the polymer matrix. The mechanical properties of the ash/PMMA composites were enhanced up to an optimum level (ash 3 wt %) and then decreased at higher incorporation of large quantity of filler. The TGA thermograms indicated that the thermal stability of the ash/PMMA composite was enhance significantly than pure PMMA.

MUHAMMAD ISHAQ; KHALID SAEED; MUHAMMAD SHAKIRULLAH; IMTIAZ AHMAD; TAYYIBA REHMAN

2012-01-01

369

EFFECT OF COAL ASH ON THE MORPHOLOGICAL, THERMAL AND MECHANICAL PROPERTIES OF POLY(METHYL METHACRYLATE)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Composite materials of Coal ash/ Poly(Methyl Methacrylate) (ash/PMMA) were prepared/synthesized and their properties were studied by scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA) and universal testing machine (UTM). The morphological study presented that the ash particles were well dispersed and embedded within the PMMA matrix. The DSC thermograms showed that the melting te (more) mperature (Tm) of pure PMMA is about 166 ºC which was shifted towards lower temperature when ash were incorporated in the polymer matrix. The mechanical properties of the ash/PMMA composites were enhanced up to an optimum level (ash 3 wt %) and then decreased at higher incorporation of large quantity of filler. The TGA thermograms indicated that the thermal stability of the ash/PMMA composite was enhance significantly than pure PMMA.

ISHAQ, MUHAMMAD; SAEED, KHALID; SHAKIRULLAH, MUHAMMAD; AHMAD, IMTIAZ; REHMAN, TAYYIBA

2012-03-01

370

Chemical and petrographical characterization of feed coal, fly ash and bottom ash from the Figueira Power Plant, Parana, Brazil  

Energy Technology Data Exchange (ETDEWEB)

The aim of the present study is the petrographic and chemical characterization of the coal at the Figueira Power Plant, Parana, Brazil, prior and after the beneficiation process and the chemical characterization of fly and bottom ashes generated in the combustion process. Petrographic characterization was carried out through maceral analysis and vitrinite reflectance measurements. Chemical characterization included proximate analysis, determination of calorific value and sulphur content, ultimate analysis, X-ray diffraction, X-ray fluorescence, Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) analysis, and determination of Total Organic Carbon (TOC) content. Vitrinite reflectance analyses indicate a high volatile B/C bituminous coal (0.61 to 0.73% Rrandom). Maceral analyses show predominance of the vitrinite maceral group (51.6 to 70.9 vol.%, m.m.f). Except of the Run of mine (ROM) coal sample, the average calorific value of the coals is 5205 kcal/kg and ash yields range from 21.4 to 38.1 wt.%. The mineralogical composition (X-ray diffraction) of coals includes kaolinite, quartz, plagioclase and pyrite, whereas fly and bottom ashes are composed by mullite, ettringite, quartz, magnetite, and hematite. Analyses of major elements from coal, fly and bottom ashes indicate a high SiO{sub 2}, Al{sub 2}O{sub 3}, and Fe{sub 2}O{sub 3} content. Trace elements analysis of in-situ and ROM coals by ICP-MS and ICP-AES show highest concentration in Zn and As. Most of the toxic elements such as As, Cd, Cr, Mo, Ni, Pb, and Zn are significantly reduced by coal beneficiation. Considering the spatial distribution of trace elements in the beneficiated coal samples, which were collected over a period of three months, there appears to be little variation in Cd and Zn concentrations, whereas trace elements such as As, Mo, and Pb show a larger variation. In the fly and bottom ashes, the highest concentrations of trace elements were determined for Zn and As. When compared with trace element concentrations in the feed coal, fly ashes show a significant enrichment in most trace elements (As, B, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Tl, and Zn), suggesting a predominantly volatile nature for these elements. In contrast, Sn is distributed evenly within the different ash types, whereas U shows depleted concentration in both bottom and fly ash samples. According to the International Classification of in-seam coals the Cambui coals are of para/ortho bituminous rank of low grade (except for the ROM sample), and are characterized by the predominance of vitrinite macerals. (author)

Levandowski, Janaina; Kalkreuth, Wolfgang [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil)

2009-01-31

371

A radioisotopic method for non-destructive estimation of ash content in coal  

International Nuclear Information System (INIS)

[en] A radioisotopic method, based on the attenuation of 133Ba ?-rays, has been developed and discussed for non-destructive estimation of ash content in coal. Choice of ?-source, its energy, and the effects of moisture, particle size and the iron content of the coal samples have been discussed in detail. Coal samples having ash content upto 47%, with iron content 0 to 15% of ash, have been studied and calibration curves for the same are plotted. Various coal samples from different coal fields like Ranigunj, Jharia, Korba, West Barboni, Bonjomihari, etc have been analysed. The results have been found in good agreement with those obtained by the common method of incineration. (auth.)

1977-02-05

372

Experimental study of sintering behaviour and heat transfer of coal ashes  

Energy Technology Data Exchange (ETDEWEB)

Sintering tests of coal ashes and measurement of thermal conductivity through ash layers were performed to obtain an understanding of ash deposition and agglomerate formation in combustion systems. The ash samples for sintering tests were prepared both by the JIS ashing procedures and by burning in a turbulent flow furnace firing 5-6 kg of coal per hour to obtain fly ash. Linear shrinkage ratio of 12 ashes formed in a cylindrical shape were measured as an index of sintering behaviour. The range of the temperatures that shrinking started was from 700{degree}C to 1100{degree}C and were much lower than the Ash Fusion Temperatures. Scanning electron microscope examination provided information that ash particles have already melted at the sintering temperature. Also thermal conductivity measurements of the fly ash layer were performed. Its mean value ranges from 0.3 W/(mK) at a mean deposit temperature of 300{degree}C to 0.45 W/(mK) at 700{degree}C. Calculation of the thickness of the particulate layer and its surface temperature was carried out using the above values. 2 refs., 6 figs., 1 tab.

Teramae, T. [Idemitsu Kosan, Co., Ltd., Chiba (Japan). Coal Research Laboratories

1997-12-31

373

Ash deposition behavior of cynara-coal blends in a PF pilot furnace  

Energy Technology Data Exchange (ETDEWEB)

Biomass is nowadays considered as a very interesting option to substitute conventional fossil fuels. Although biomass could be burnt alone, it can also be co-fired together with coal in existing power plants, at a lower cost. One of the main problems related with biomass used in thermal applications is its propensity to form ash deposits. Slagging and fouling caused by ash may derive in heat transfer losses, corrosion in the tubes or even boiler shutdown. A deposition probe has been designed and proved to study this phenomenon. Several combustion tests have been performed in a 500 kW{sub th} PF pilot test rig burning cynara blended with two coals at different shares in energy basis. Different analyses have been performed to those ash samples collected during the tests. From the results, it is observed that the quantity of collected ash in the deposition probe did not increase noticeably when increasing the biomass share up to 15% in energy basis. However, the opposite was detected in Spanish coal tests, due to its higher ash content. Major components of ash samples were aluminosilicates coming from coal clays. These components may act as protective ash coal compounds, but inorganic elements such as calcium or potassium also appeared and their presence increased with the biomass share. Although chlorine content in cynara was high, no important presence of this element was encountered in none of the ash samples collected. Experimental results agree with other experimental studies showing that aluminosilicates from coals may act as protective ash compounds, preventing chlorine deposition on heat transfer surfaces. The beneficial effect is also detected at pulverized fuel conditions. (author)

Bartolome, C.; Gil, A.; Ramos, I.

2010-11-15

374

Brick manufacture with fly ash from Illinois coals. Technical report, March 1, 1995--May 31, 1995  

Energy Technology Data Exchange (ETDEWEB)

This investigation seeks to utilize fly ash in fired-clay products such as building and patio bricks, ceramic blocks, field and sewer tile, and flower pots. This goal is accomplished by 1) one or more plant-scale, 5000-brick tests of fly ash mixed with brick clays at the 20% or higher level; 2) a laboratory-scale study to measure the firing reactions of a range of compositions of clay and fly ash mixtures; 3) a preliminary study to evaluate the potential environmental and economic benefits of brick manufacture with fly ash. Bricks and feed materials will be tested for compliance with market specifications and for leachability of pollutants derived from fly ash. The laboratory study will combine ISGS databases, ICCI-supported characterization methods, and published information to improve predictions of the firing characteristics of Illinois fly ash and brick clay mixtures. Because identical methods are used to test clay firing and coal ash fusion, and because melting mechanisms are the same, improved coal ash fusion predictions are and additional expected result of this research. During this quarter we completed a manufacturing run at Colonial Brick Co. and began laboratory testing of samples from that run: clays, fly ash (from Illinois Power Company`s Wood River plant), and green and fired bricks, with and without fly ash. Bricks with 20% fly ash ``scummed`` during firing, and the fly ash failed to increase oxidation rate or water absorption, which were both expected. We obtained chemical and mineralogical analyses of the fireclays and shales at Colonial and Marseilles Brick Companies and began a series of selective dissolution analyses to more accurately determine the composition of the principal clay minerals in brick clays and the components in fly ash. We began related work of calculating normative mineralogical analyses for all clays and fly ashes that we sample.

Hughes, R.E.; Dreher, G.; Moore, D.; Rostam-Abadi, M. [Illinois State Geological Survey, Urbana, IL (United States); Fiocchi, T. [Illinois Power Co. (United States); Swartz, D. [Colonial Brick Co. (United States)

1995-12-31

375

Synchrotron-radiation-induced oxidation of selenite to selenate in coal-derived fly ash  

International Nuclear Information System (INIS)

Systematic changes observed in consecutive XANES spectra of selenium in samples of fly ash from a power plant in Alberta, Canada, burning subbituminous coal have been interpreted as arising from synchrotronradiation- induced oxidation of a selenite species to selenate. It was estimated that about 15-20% of the selenite was oxidized to selenate during the 2 h exposure of the fly ash to the synchrotron beam. In contrast, the XANES spectra of arsenic (and other trace elements not documented herein) showed no variation. It is believed that this is the first time that radiation-induced changes have been observed for an element in coal-derived fly ash. (orig.)

2011-01-01

376

Synchrotron-radiation-induced oxidation of selenite to selenate in coal-derived fly ash  

Energy Technology Data Exchange (ETDEWEB)

Systematic changes observed in consecutive XANES spectra of selenium in samples of fly ash from a power plant in Alberta, Canada, burning subbituminous coal have been interpreted as arising from synchrotronradiation- induced oxidation of a selenite species to selenate. It was estimated that about 15-20% of the selenite was oxidized to selenate during the 2 h exposure of the fly ash to the synchrotron beam. In contrast, the XANES spectra of arsenic (and other trace elements not documented herein) showed no variation. It is believed that this is the first time that radiation-induced changes have been observed for an element in coal-derived fly ash. (orig.)

Huggins, Frank E. [Kentucky Univ., Lexington, KY (United States). CFFS/CME; Sanei, Hamed [Natural Resources Canada, Calgary, AB (Canada)

2011-05-15

377

Radiological significance of coal, slag and fly ash samples from the Eastern Black Sea region  

International Nuclear Information System (INIS)

[en] This work presents a study of natural radioactivity levels in coal and its combustion residues (fly ash and slag) used in the houses in Black Sea Region, Turkey. Coal, fly ash and slag samples were provided from different locations of the region and analyzed by gamma spectroscopy using a high-purity germanium detector (HPGe). Also, chemical analyses of these samples were carried out using energy dispersive X-ray fluorescence spectrometer. The mean 226Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg-1, respectively. The mean 232Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg-1, respectively. The mean 40K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg-1, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Raeq), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (Hex) and internal hazard index (Hin) and compared with the internationally accepted or reference values. The mean Raeq values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg-1 by the Organization for Economic Cooperation and Development (OECD). The overall mean outdoor terrestrial gamma air absorbed dose rate in coal, fly ash and slag samples are 119, 129 and 62 nGy h-1 and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y-1, which is higher than the worldwide average (0.07 mSv y-1), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for 226Ra and 232Th were found 1.14 and 1.01, respectively. (orig.)

2012-01-01

378

Mineral sequestration of CO2 by aqueous carbonation of coal combustion fly-ash  

International Nuclear Information System (INIS)

The increasing CO2 concentration in the Earth's atmosphere, mainly caused by fossil fuel combustion, has led to concerns about global warming. A technology that could possibly contribute to reducing carbon dioxide emissions is the in-situ mineral sequestration (long term geological storage) or the ex-situ mineral sequestration (controlled industrial reactors) of CO2. In the present study, we propose to use coal combustion fly-ash, an industrial waste that contains about 4.1 wt.% of lime (CaO), to sequester carbon dioxide by aqueous carbonation. The carbonation reaction was carried out in two successive chemical reactions, first, the irreversible hydration of lime. CaO + H2O ? Ca(OH)2 second, the spontaneous carbonation of calcium hydroxide suspension. Ca(OH)2 + CO2 ? CaCO3 + H2O A significant CaO-CaCO3 chemical transform