Recommendations for conversions of grate fired boilers to fluidising beds; Anvisningar foer konvertering av rosterpannor till fluidiserad baeddteknik

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Lars; Ingman, Rolf [AaF Energikonsult AB, Stockholm (Sweden)

2001-03-01

This report gives advice and recommendations for retrofitting of grate fired boilers to fluidising beds. Nine plants have been visited and experiences from these conversion projects have been gathered and analysed. Among the important points planning, fuel specification, heat balance calculations and clarifying of delivery limits can be mentioned. It is also important not to underestimate the need for education of the operational staff.

Installations of SNCR on bark-fired boilers

International Nuclear Information System (INIS)

Hjalmarsson, A.K.; Hedin, K.; Andersson, Lars

1997-01-01

Experience has been collected from the twelve bark-fired boilers in Sweden with selective non catalytic reduction (SNCR) installations to reduce emissions of nitrogen oxides. Most of the boilers have slope grates, but there are also two boilers with cyclone ovens and two fluidized bed boilers. In addition to oil there are also possibilities to burn other fuel types in most boilers, such as sludge from different parts of the pulp and paper mills, saw dust and wood chips. The SNCR installations seems in general to be of simple design. In most installations the injection nozzles are located in existing holes in the boiler walls. The availability is reported to be good from several of the SNCR installations. There has been tube leakage in several boilers. The urea system has resulted in corrosion and in clogging of one oil burner. This incident has resulted in a decision not to use SNCR system with the present design of the system. The fuel has also caused operational problems with the SNCR system in several of the installations due to variations in the moisture content and often high moisture content in bark and sludge, causing temperature variations. The availability is presented to be high for the SNCR system at several of the plants, in two of them about 90 %. The results in NO x reduction vary between the installations depending on boiler, fuel and operation. The emissions are between 45 and 100 mg NO 2 /MJ fuel input and the NO x reduction rates are in most installations between 30 and 40 %, the lowest 20 and the highest 70 %. 13 figs, 3 tabs

Re-burning of ash in grate boilers; Omfoerbraenning av askor i rosterpannor

Energy Technology Data Exchange (ETDEWEB)

Bergqvist, Kristina; Myringer, Aase; Nordgren, Daniel; Rydberg, Stina [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

2005-03-01

High contents of unburnt carbon in ashes that are dumped or recycled, is questionable from both an economical and an environmental point of view. The content of unburnt carbon in bottom and fly ash from grate boilers varies greatly between different plants but can sometimes exceed 50 %. Re-burning of ash that is separated before a final dust separation, is a relatively cheep and simple method for reducing the content of unburnt carbon in ash, which both reduces the fuel cost and the deposit cost, i.e. the cost of landfilling or recycling. As from 2005 it is prohibited to deposit ash with a too high content of unburnt organic material; the content is limited to 18 weight % of unburnt carbon. The study was carried out in two phases. The aim of the first phase was to map the different techniques used for re-burning ash that are used in grate boilers today. The mapping was done through telephone interviews and comprises technical descriptions of the systems, gathering of operational know-how, installations costs and the effect of the systems on the amount of ash generated at the plants and the content of unburnt carbon in the ash. In order to accomplish a deeper technical and economical evaluation of ash re-burning systems, the second phase involved field studies at two plants. In addition screening tests were done to investigate the connection between the content of unburnt carbon and particle size. The potential of reducing the amount of circulated inorganic material by sieving the ash before bringing it back to the furnace could thereby be determined. 13 plants that utilize re-burning of ash were identified, of which two plants re-burn the bottom ash that floats up to the surface in the wet ash removal system. The remaining 11 plants re-burn fly ash. At three plants the fly ash is first separated in a mesh sieve or similar equipment and only the coarser fly ash is re-burnt. As the amount of bottom ash that surfaces in the wet ash-removal is relatively small

Engineering bed models for solid fuel conversion process in grate-fired boilers

DEFF Research Database (Denmark)

Costa, M.; Massarotti, N.; Indrizzi, V.

2014-01-01

of the syngas predicted by the two models is equal to about 7%. The application to different types of biomass shows that the difference in the predictions increases as the carbon content grows. The phenomenological model, in fact, generally considers higher conversion rates of this element to volatiles......A comparison between two numerical models describing the thermo-chemical conversion process of a solid fuel bed in a grate-fired boiler is presented. Both models consider the incoming biomass as subjected to drying, pyrolysis, gasification and combustion. In the first approach the biomass bed...... is treated as a 0D system, where the thermo-chemical processes are divided in two successive sections: drying and conversion. Phenomenological laws are written to characterize the syngas release as a function of the main governing parameters. The second model is an empirical 1D approach. Temperature, species...

Bed models for solid fuel conversion process in grate-fired boilers

DEFF Research Database (Denmark)

Costa, M.; Massarotti, N.; Indrizzi, V.

2013-01-01

-chemical processes are divided in two successive sections: drying and conversion (which includes pyrolysis, gasification and combustion). The second model is an empirical 1D approach. The two models need input data such as composition, temperature and feeding rate of biomass and primary air. Temperature, species...... to describe the thermo-chemical conversion process of a solid fuel bed in a grate-fired boiler is presented. In this work both models consider the incoming solid fuel as subjected to drying, pyrolysis, gasification and combustion. In the first approach the biomass bed is treated as a 0D system, but the thermo...... concentrations and velocity of the producer gas leaving the fuel bed provided by the two models are compared. A sensitivity analysis with respect to mass flow rate of the primary air is also performed, as well as a further comparison regarding the dependence of the producer gas properties on the initial moisture...

Emission and properties of NO{sub x} generated during coal grate-fired in O{sub 2}/N{sub 2}/CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xu, Li; Gao, Jian-min; Zhao, Lai-fu; Zhao, Guang-bo; Wu, Shaohua [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.

2013-07-01

With the improvement of environmental protection requirements, the problems of NO{sub x} emission from industrial boiler become more and more notable. Flue gas recirculation is a low-NO{sub x} combustion technology. It draws out a part of the flue gas from rear flue and forces it into boiler. So the flue gas can serve the combustion or flow field integration. The drawn flue gas can be forced into the boiler directly, or mixed with the primary air or secondary air. To explore a real effective method of low NO{sub x} combustion, the article discusses the influence of flue gas recirculation on the formation of NO{sub x} in the process of coal grate-fired, in the way of using the unit-boiler, measuring the temperature of coal surface and composition and other important influential parameters. Experimental studies show that under the condition of grate-fired, taking Flue gas recirculation in main combustion zone, coke combustion zone and burn-out zone could notably diminish the amount of NO. And with the promotion of flue gas recirculation rate, the effect can be more noticeable.

An emissions audit of a chain grate stoker burning coal

International Nuclear Information System (INIS)

Jackson, P.M.; King, P.G.

1993-01-01

This report describes the Emissions Audit carried out on a chain-grate stoker boiler burning coal. The boiler rated at 4.6MW(th) was installed at the Senior Foster Wheeler test facility in Wakefield where it had been modified so that it could burn both coal and dRDF. This report is based on test work undertaken as part of a programme to assess the environmental impact of the combustion of a variety of wastes as fuels. Emissions monitoring tests were carried out using coal as the fuel for comparison with the other wastes. Combustion of coal in boilers of this size are regulated by the Clean Air Acts whilst combustion of wastes is regulated by the more recent Environmental Protection Act. (author)

Release of Corrosive Species above the Grate in a Waste Boiler and the Implication for Improved Electrical Efficiency

DEFF Research Database (Denmark)

Bøjer, Martin; Jensen, Peter Arendt; Dam-Johansen, Kim

2010-01-01

A relatively low electrical efficiency of 20−25% is obtained in typical west European waste boilers. Ash species released from the grate combustion zone form boiler deposits with high concentrations of Cl, Na, K, Zn, Pb, and S that cause corrosion of superheater tubes at high temperature....... The superheater steam temperature has to be limited to around 425 °C, and thereby, the electrical efficiency remains low compared to wood or coal-fired boilers. If a separate part of the flue gas from the grate has a low content of corrosive species, it may be used to superheat steam to a higher temperature......, and thereby, the electrical efficiency of the plant can be increased. In this study, the local temperature, the gas concentrations of CO, CO2, and O2, and the release of the volatile elements Cl, S, Na, K, Pb, Zn, Cu, and Sn were measured above the grate in a waste boiler to investigate if a selected fraction...

SRC burn test in 700-hp oil-designed boiler. Annex Volume C. Boiler emission report. Final technical report

Energy Technology Data Exchange (ETDEWEB)

1983-09-01

The Solvent-Refined Coal (SRC) test burn program was conducted at the Pittsburgh Energy Technology Center (PETC) located in Bruceton, Pa. One of the objectives of the study was to determine the feasibility of burning SRC fuels in boilers set up for fuel oil firing and to characterize emissions. Testing was conducted on the 700-hp oil-fired boiler used for research projects. No. 6 fuel oil was used for baseline data comparison, and the following SRC fuels were tested: SRC Fuel (pulverized SRC), SRC Residual Oil, and SRC-Water Slurry. Uncontrolled particulate emission rates averaged 0.9243 lb/10/sup 6/ Btu for SRC Fuel, 0.1970 lb/10/sup 6/ Btu for SRC Residual Oil, and 0.9085 lb/10/sup 6/ Btu for SRC-Water Slurry. On a lb/10/sup 6/ Btu basis, emissions from SRC Residual Oil averaged 79 and 78%, respectively, lower than the SRC Fuel and SRC-Water Slurry. The lower SRC Residual Oil emissions were due, in part, to the lower ash content of the oil and more efficient combustion. The SRC Fuel had the highest emission rate, but only 2% higher than the SRC-Water Slurry. Each fuel type was tested under variable boiler operating parameters to determine its effect on boiler emissions. The program successfully demonstrated that the SRC fuels could be burned in fuel oil boilers modified to handle SRC fuels. This report details the particulate emission program and results from testing conducted at the boiler outlet located before the mobile precipitator take-off duct. The sampling method was EPA Method 17, which uses an in-stack filter.

Researching the Performance of Dual-Chamber Fire-Tube Boiler Furnace

Directory of Open Access Journals (Sweden)

Khaustov Sergei

2015-01-01

Full Text Available Autonomous heating systems equipped with fire-tube or shell boilers show high effectiveness, consistent performance and great technical parameters. But there is a significant limitation of its thermal productivity due to the complexity of durable large diameter fire-tube bottoms implementation. Optimization of combustion aerodynamics can be the way to expand the fire-tube boilers performance limit. In this case lots of problems connected with reducing emissions of toxic substances, providing of burning stability, local heat stresses and aerodynamic resistances should be solved. To resolve the indicated problems, a modified model of dual-chamber fire-tube boiler furnace is proposed. The performance of suggested flame-tube was simulated using the proven computer-aided engineering software ANSYS Multiphysics. Results display proposed flame tube completely filled with moving medium without stagnant zones. Turbulent vortical combustion is observed even with the straight-through fuel supply. Active flue gas recirculation in suggested dual-chamber furnace reduces emissions of pollutants. Diminution of wall heat fluxes allows boiler operation at lower water treatment costs.

Installations of SNCR on bark-fired boilers; Uppfoeljning av SNCR-installationer paa barkpannor

Energy Technology Data Exchange (ETDEWEB)

Hjalmarsson, A.K.; Hedin, K. [AaF-Energikonsult, Stockholm (Sweden); Andersson, Lars [AaF-IPK (Sweden)

1997-01-01

Experience has been collected from the twelve bark-fired boilers in Sweden with selective non catalytic reduction (SNCR) installations to reduce emissions of nitrogen oxides. Most of the boilers have slope grates, but there are also two boilers with cyclone ovens and two fluidized bed boilers. In addition to oil there are also possibilities to burn other fuel types in most boilers, such as sludge from different parts of the pulp and paper mills, saw dust and wood chips. The SNCR installations seems in general to be of simple design. In most installations the injection nozzles are located in existing holes in the boiler walls. The availability is reported to be good from several of the SNCR installations. There has been tube leakage in several boilers. The urea system has resulted in corrosion and in clogging of one oil burner. This incident has resulted in a decision not to use SNCR system with the present design of the system. The fuel has also caused operational problems with the SNCR system in several of the installations due to variations in the moisture content and often high moisture content in bark and sludge, causing temperature variations. The availability is presented to be high for the SNCR system at several of the plants, in two of them about 90 %. The results in NO{sub x} reduction vary between the installations depending on boiler, fuel and operation. The emissions are between 45 and 100 mg NO{sub 2}/MJ fuel input and the NO{sub x} reduction rates are in most installations between 30 and 40 %, the lowest 20 and the highest 70 %. 13 figs, 3 tabs

Ash transformation and deposit build-up during biomass suspension and grate firing: Full-scale experimental studies

DEFF Research Database (Denmark)

Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

2012-01-01

An attractive option for reducing the net CO2 emissions is to substitute coal with biomass in large power plant boilers. However, the presence of chlorine (Cl) and alkali metals (K, Na) in biomassmay induce large operational problems due to ash deposit formation on the superheater tubes. The aim...... of this study was to investigate ash transformation and deposition behavior in two biomass-fired boilers, firing wheat straw and/or wood. The influence of strawfiring technology (grate and suspension) on the ash transformation, deposit formation rate and deposit characteristics has been investigated. Bulk...... elemental analysis of fly ashes revealed that fly ash from suspension firing of straw has high contents of Si, K and Ca, while fly ash from straw firing on grate was rich in the volatile elements K, Cl and S. Investigations of deposit formation ratesweremade in the superheater and convective pass regions...

Particulate and un burned carbon emissions reduction from oil fired boilers using combustion promoters

Energy Technology Data Exchange (ETDEWEB)

Balsiger, Andreas; Carvalho, Jose Guilherme de [ACOTEQ, Rio de Janeiro, RJ (Brazil)

1993-12-31

This paper describes the results obtained in the tests carried out with a combustion promoter on a 530 MW utility boiler, in order to reduce solid particle emissions in steady state and transient operations. Tests have been performed at Unit II of Bahia de Algeciras Power Station, owned by Sevillana de Electricidad. Sevillana de Electricidad activities include the production, transmission and distribution of electric power. The distribution area is 40000 square miles (aprox. 20% of peninsular Spains territory).Companys total capacity is 4400 MW, of which 1476 are fuel-oil fired. The demand for electricity in the market served by Sevillana has been 18345 GWh in 1989. Fuel-oil plants output was only 1,6% of total demand in accordance with Spanish energy policy guidelines. Along tests described in this paper, steady state emission, are expected to be reduced due to depletion of the un burned carbon content in particulates. Transient operation emissions should also be reduced if the boiler is kept clean to eliminating soot blowing requirements. (author) 9 refs., 6 figs., 5 tabs.

Effects of combustion and operating conditions on PCDD/PCDF emissions from power boilers burning salt-laden wood waste.

Science.gov (United States)

Leclerc, Denys; Duo, Wen Li; Vessey, Michelle

2006-04-01

This paper discusses the effects of combustion conditions on PCDD/PCDF emissions from pulp and paper power boilers burning salt-laden wood waste. We found no correlation between PCDD/PCDF emissions and carbon monoxide emissions. A good correlation was, however, observed between PCDD/PCDF emissions and the concentration of stack polynuclear aromatic hydrocarbons (PAHs) in the absence of TDF addition. Thus, poor combustion conditions responsible for the formation of products of incomplete combustion (PICs), such as PAHs and PCDD/PCDF precursors, increase PCDD/PCDF emissions. PAH concentrations increased with higher boiler load and/or low oxygen concentrations at the boiler exit, probably because of lower available residence times and insufficient excess air. Our findings are consistent with the current understanding that high ash carbon content generally favours heterogeneous reactions leading to either de novo synthesis of PCDD/PCDFs or their direct formation from precursors. We also found that, in grate-fired boilers, a linear increase in the grate/lower furnace temperature produces an exponential decrease in PCDD/PCDF emissions. Although the extent of this effect appears to be mill-specific, particularly at low temperatures, the results indicate that increasing the combustion temperature may decrease PCDD/PCDF emissions. It must be noted, however, that there are other variables, such as elevated ESP and stack temperatures, a high hog salt content, the presence of large amounts of PICs and a high Cl/S ratio, which contribute to higher PCDD/PCDFs emissions. Therefore, higher combustion temperatures, by themselves, will not necessarily result in low PCDD/PCDFs emissions.

Improved NOx emissions and combustion characteristics for a retrofitted down-fired 300-MWe utility boiler.

Science.gov (United States)

Li, Zhengqi; Ren, Feng; Chen, Zhichao; Liu, Guangkui; Xu, Zhenxing

2010-05-15

A new technique combining high boiler efficiency and low-NO(x) emissions was employed in a 300MWe down-fired boiler as an economical means to reduce NO(x) emissions in down-fired boilers burning low-volatile coals. Experiments were conducted on this boiler after the retrofit with measurements taken of gas temperature distributions along the primary air and coal mixture flows and in the furnace, furnace temperatures along the main axis and gas concentrations such as O(2), CO and NO(x) in the near-wall region. Data were compared with those obtained before the retrofit and verified that by applying the combined technique, gas temperature distributions in the furnace become more reasonable. Peak temperatures were lowered from the upper furnace to the lower furnace and flame stability was improved. Despite burning low-volatile coals, NO(x) emissions can be lowered by as much as 50% without increasing the levels of unburnt carbon in fly ash and reducing boiler thermal efficiency.

Characterization and Quantification of Deposits Buildup and Removal in Biomass Suspension-Fired Boilers

DEFF Research Database (Denmark)

Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

2010-01-01

Utilization of biomass as wood or straw in large suspension­fired boilers is an efficient method to reduce the use of fossil fuels consumption and to reduce the net CO2 formation. However, the presence of chlorine and alkali metals in biomass (straw) generate ash with a low melting point and induce...... large problems of ash deposit formation on the superheater tubes. Full scale studies on biomass ash deposition and removal had been done on biomass grate boilers, while only limited data is available from biomass suspension­firing. The aim of this study was to investigate deposit mass uptake, heat...... uptake reduction, fly ash and deposit characteristics, and deposit removal by using an advanced online deposit probe in a suspension­fired boiler using wood and straw pellets as fuel. The influence of fuel type and probe exposure time on the ash deposition rate, the heat uptake, the fly ash and deposit...

An emissions audit from a chain-grate stoker burning d-RDF

International Nuclear Information System (INIS)

Jackson, P.M.; King, P.G.

1993-01-01

This report describes the Emissions Audit carried out on a chain-grate stoker shell boiler burning dRDF at the Senior Foster Wheeler test facility in Wakefield to provide design data for gas cleaning equipment. Sampling was therefore performed in the absence of any abatement equipment other than a standard cyclonic grit arrestor. The chain-grate stoker boiler was tested at two steam loads: 40% MCR to represent low load and, 80% MCR to represent high steam load. Acid gas concentrations in the flue gas were unacceptable. The dominant gas being HCl at 850-1000mgm -3 for both tests, was considerably higher than the guideline for new plant of 50mgm -3 . HF was also measured at concentrations in excess of the guidance value. It will be necessary to install acid gas scrubbing equipment before dRDF will be acceptable as a fuel. SO 2 and NO x were both present in measurable concentrations but under current guidance were no cause for concern. (author)

Co-firing of coal with biomass and waste in full-scale suspension-fired boilers

Energy Technology Data Exchange (ETDEWEB)

Dam-Johansen, Kim; Frandsen, Flemming J.; Jensen, Peter A.; Jensen, Anker D. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of chemical and Biochemical Engineering

2013-07-01

The energy policy in Denmark has for many years focused on lowering the net CO{sub 2} emission from heat and power production by replacing fossil fuels by renewable resources. This has been done by developing dedicated grate-fired boilers for biomass and waste fuels but also by developing coal-based suspension-fired boilers to accept still higher fractions of biomass or waste material as fuels. This last development has been challenging of many reasons, including pre-treatment of fuels, and solving potential emission and operational problems during the simultaneous development of supercritical steam cycles with steam temperatures close to 600 C, providing power efficiencies close to 50% (Hein KRG, Sustainable energy supply and environment protection - strategies, resources and technologies. In: Gupta R, Wall T, Hupa M, Wigley F, Tillman D, Frandsen FJ (eds) Proceedings of international conference on impact of fuel quality on power production and the environment, Banff Conference Centre, Banff, Alberta, Canada, 29 Sept-4 Oct, 2008). For 25 years the CHEC (Combustion and Harmful Emission Control) Research Centre at DTU Chemical Engineering, has attained a leading role in research, supporting power producing industry, plant owners and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools. The research conducted has addressed many issues important for co-firing, i.e. fuel processing, ash induced boiler deposit formation and corrosion, boiler chamber fuel conversion and emission formation, influence on flue gas cleaning equipment and the utilization of residual products. This chapter provides an overview of research activities, aiming at increasing biomass shares during co-firing in suspension, conducted in close collaboration with

40 CFR 63.1217 - What are the standards for liquid fuel boilers that burn hazardous waste?

Science.gov (United States)

2010-07-01

... boilers that burn hazardous waste? 63.1217 Section 63.1217 Protection of Environment ENVIRONMENTAL... that burn hazardous waste? (a) Emission limits for existing sources. You must not discharge or cause... paragraph (a)(2)(iii) of this section: (i) When you burn hazardous waste with an as-fired heating value less...

Slagging and fouling evaluation of PC-fired boilers using AshPro{sup SM}

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhanhua; Iman, Felicia; Lu, Pisi [SmartBurn, LLC, Madison, WI (United States)

2013-07-01

SmartBurn {sup registered} applied AshPro{sup SM} model to two 512 MW Tangential-fired (T-fired) boilers firing US western sub- bituminous coals to evaluate the boiler slagging behaviors with different operating conditions and OFA. The boiler convective pass fouling behaviors with three different coals were also evaluated. The slagging evaluation results indicate that the OFA configuration and air flow distribution have dramatically impacts on the ash impaction rates and slagging patterns on the furnace walls. Deposit growth and strength vary at the different regions of the furnace walls. The fouling evaluation reveals that the tube bank configuration, the amount of incoming ash, the profiles of flue gas temperature, velocity, and species all have significant impacts on fouling deposit formation, growth, and strength development. In addition, the varying ash particle sizes and chemical compositions from different coals also play important roles on the fouling deposit strength development and removal. The investigation demonstrated that AshPro{sup SM} model can be used to evaluate localized slagging and fouling problems that are related to specific boiler configuration and operating conditions. It can be used to identify the major causes of ash deposition and can guide changes in boiler operation.

40 CFR 266.110 - Waiver of DRE trial burn for boilers.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Waiver of DRE trial burn for boilers... HAZARDOUS WASTE MANAGEMENT FACILITIES Hazardous Waste Burned in Boilers and Industrial Furnaces § 266.110 Waiver of DRE trial burn for boilers. Boilers that operate under the special requirements of this section...

Simulation of pulverized coal fired boiler: reaction chamber

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, C.P.; Lansarin, M.A.; Secchi, A.R.; Mendes, T.F. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica. Grupo de Modelagem, Simulacao, Controle e Otimizacao de Processos)]. E-mail: {cperdomo, marla, arge, talita}@enq.ufrgs.br

2005-06-15

This work is part of a joint project to built a computational tool for power plant simulation, dealing specifically with the reaction chamber (place of the boiler where the fuel is burned). In order to describe the conversion of chemical energy to thermal energy, an one dimensional pseudo-homogeneous mathematical model, with variable physical properties, and based on mass and energy balances, was developed. The equations were implemented in the gPROMS simulator and the model parameters were estimated using the module gEST of this software, with experimental data from a large-scale coal-fired utility boiler and kinetic data from the open literature. The results showed that the model predicts the composition of the outlet combustion gas satisfactorily. (author)

Boiler conversions for biomass

Energy Technology Data Exchange (ETDEWEB)

Kinni, J [Tampella Power Inc., Tampere (Finland)

1997-12-31

Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

Boiler conversions for biomass

Energy Technology Data Exchange (ETDEWEB)

Kinni, J. [Tampella Power Inc., Tampere (Finland)

1996-12-31

Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

Computer simulation of the fire-tube boiler hydrodynamics

Directory of Open Access Journals (Sweden)

Khaustov Sergei A.

2015-01-01

Full Text Available Finite element method was used for simulating the hydrodynamics of fire-tube boiler with the ANSYS Fluent 12.1.4 engineering simulation software. Hydrodynamic structure and volumetric temperature distribution were calculated. The results are presented in graphical form. Complete geometric model of the fire-tube boiler based on boiler drawings was considered. Obtained results are suitable for qualitative analysis of hydrodynamics and singularities identification in fire-tube boiler water shell.

Feasibility of applying coal-fired boiler technology to process heaters

Energy Technology Data Exchange (ETDEWEB)

O' Sullivan, T F

1978-01-01

The preponderance of coal in US fossil fuel reserves has raised the question of the conversion of hydrocarbon process heaters to coal firing. A review undertaken in 1977 by an API sub-committee concluded that neither existing heaters nor existing heater designs were capable of modification or revision to burn coal, and that new coal-fired design consistent with process requirements would be needed for this purpose. In recognition of this need a cooperative investigation was undertaken by Combustion Engineering and Lummus. The present paper, reporting on this investigation, reviews existing coal-fired boiler equipment and techniques and describes their adaptation to the development of a design concept for a coal-fired process heater. To this end, the design parameters for both steam boilers and fired heaters have been compared and have been incorporated into a workable coal-fired process heater design which includes the following features; a coutant bottom for ash removal, an ash-hopper located under both radiant and convection chambers, a tangent type finned wall construction, a straight through gas flow pattern, a vertical tube convection section, horizontal firing using round burners, and an overall geometry allowing a coil arrangement capable of accommodating varying numbers of parallel serpentine coils. These features are integrated into a conceptual heater design which is detailed in a series of illustrations.

DEMONSTRATION OF SORBENT INJECTION TECHNOLOGY ON A TANGENTIALLY COAL-FIRED UTILITY BOILER (YORKTOWN LIMB DEMONSTRATION)

Science.gov (United States)

The report summarizes activities conducted and results achieved in an EPA-sponsored program to demonstrate Limestone Injection Multistage Burner (LIMB) technology on a tangentially fired coal-burning utility boiler, Virginia Power's 180-MWe Yorktown Unit No. 2. his successfully d...

Gas fired boilers and atmospheric pollution

International Nuclear Information System (INIS)

Chiaranello, J.M.

1991-01-01

A general analysis concerning atmospheric pollution is presented: chemical composition and vertical distribution of atmosphere and pollutants, chemical reactions, ozone destruction and production cycles, COx, NOx and SOx pollutions. The gas fired boiler number and repartition in France are presented and the associated pollution is analyzed (CO2, CO, NOx) and quantified. Various pollution control technics concerning gas fired boiler pollutants are described and a pollution criterion for clean gas fired generators is proposed

Analysis and study on the membrane method of CO2 removal of coal-fired boilers

International Nuclear Information System (INIS)

Fangqin, Li; Henan, Li; Jianxing, Ren; Jiang, Wu; Zhongzhu, Qiu

2010-01-01

Carbon dioxide (CO 2 ) is one kind of harmful substances from the burning process of fossil fuel. CO 2 emissions cause serious pollution on atmospheric environment, especially greenhouse effect. In this paper, CO 2 formation mechanism and control methods were researched. Membrane technology was studied to control CO 2 emissions from coal-fired boilers. The relationship between CO 2 removal efficiency and parameters of membrane contactor was analyzed. Through analysis and study, factors affecting on CO 2 removal efficiency were gotten. How to choose the best parameters was known. This would provide theoretical basis for coal-fired utility boilers choosing effective way of CO 2 removal. (author)

Ash transformation in suspension fired boilers co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

In this literature report is provided a status for the present knowledge level on ash properties when co-firing coal and biomass. The fly ash formed in boilers using co-firing of coal and straw do have a large influence on ash deposit formation, boiler corrosion, fly ash utilization and operation...

Utilization of coal-water fuels in fire-tube boilers

International Nuclear Information System (INIS)

Sommer, T.M.; Melick, T.A.

1991-01-01

The Energy and Environmental Research Corporation (EER), in cooperation with the University of Alabama and Jim Walter Resources, has been awarded a DOE contract to retrofit an existing fire-tube boiler with a coal-water slurry firing system. Recognizing that combustion efficiency is the principle concern when firing slurry in fire-tube boilers, EER has focused the program on innovative approaches for improving carbon burnout without major modifications to the boiler. This paper reports on the program which consists of five tasks. Task 1 provides for the design and retrofit of the host boiler to fire coal-water slurry. Task 2 is a series of optimization tests that will determine the effects of adjustable parameters on boiler performance. Task 3 will perform about 1000 hours of proof-of-concept system tests. Task 4 will be a comprehensive review of the test data in order to evaluate the economics of slurry conversions. Task 5 will be the decommissioning of the test facility if required

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

Science.gov (United States)

Xu, Jiao; Li, Mei; Shi, Guoliang; Wang, Haiting; Ma, Xian; Wu, Jianhui; Shi, Xurong; Feng, Yinchang

2017-11-15

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size. Mass spectra signatures of two samples were studied by analyzing the average mass spectrum of each particle cluster extracted by ART-2a in different size ranges. In conclusion, BBB sample mostly consists of OC and EC containing particles, and a small fraction of K-rich particles in the size range of 0.2-0.5μm. In 0.5-1.0μm, BBB sample consists of EC, OC, K-rich and Al_Silicate containing particles; CBB sample consists of EC, ECOC containing particles, while Al_Silicate (including Al_Ca_Ti_Silicate, Al_Ti_Silicate, Al_Silicate) containing particles got higher fractions as size increase. The similarity of single particle mass spectrum signatures between two samples were studied by analyzing the dot product, results indicated that part of the single particle mass spectra of two samples in the same size range are similar, which bring challenge to the future source apportionment activity by using single particle aerosol mass spectrometer. Results of this study will provide physicochemical information of important sources which contribute to particle pollution, and will support source apportionment activities. Copyright © 2017. Published by Elsevier B.V.

High Temperature Corrosion in Biomass-Fired Boilers

DEFF Research Database (Denmark)

Henriksen, Niels; Montgomery, Melanie; Hede Larsen, Ole

2002-01-01

condense on superheater components. This gives rise to specific corrosion problems not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. To avoid such high corrosion rates, woodchip...... has also been utilised as a fuel. Combustion of woodchip results in a smaller amount of ash, and potassium and chlorine are present in lesser amounts. However, significant corrosion rates were still seen. A case study of a woodchip fired boiler is described. The corrosion mechanisms in both straw-fired...... and woodchip fired boilers are discussed....

46 CFR 62.35-20 - Oil-fired main boilers.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Oil-fired main boilers. 62.35-20 Section 62.35-20... AUTOMATION Requirements for Specific Types of Automated Vital Systems § 62.35-20 Oil-fired main boilers. (a) General. (1) All main boilers, regardless of intended mode of operation, must be provided with the...

Advanced technique for computing fuel combustion properties in pulverized-fuel fired boilers

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (Russian Federation))

1992-03-01

Reviews foreign technical reports on advanced techniques for computing fuel combustion properties in pulverized-fuel fired boilers and analyzes a technique developed by Combustion Engineering, Inc. (USA). Characteristics of 25 fuel types, including 19 grades of coal, are listed along with a diagram of an installation with a drop tube furnace. Characteristics include burn-out intensity curves obtained using thermogravimetric analysis for high-volatile bituminous, semi-bituminous and coking coal. The patented LFP-SKM mathematical model is used to model combustion of a particular fuel under given conditions. The model allows for fuel particle size, air surplus, load, flame height, and portion of air supplied as tertiary blast. Good agreement between computational and experimental data was observed. The method is employed in designing new boilers as well as converting operating boilers to alternative types of fuel. 3 refs.

Analysis and study on the performance variation of SCR DeNOx catalyst of Coal-Fired Boilers

International Nuclear Information System (INIS)

Jianxing, Ren; Fangqin, Li; Jiang, Wu; Qingrong, Liu; Yongwen, Yang; Zhongzhu, Qiu

2010-01-01

Nitrogen oxides (NO x ) are one kind of harmful substances from the burning process of fossil fuel and air at high temperature. NO x emissions cause serious pollution on atmospheric environment. In this paper, coal-fired utility boilers were chosen as the object, NO x formation mechanism and control were studied, and SCR deNO x technology was used to control NO x emissions from coal-fired boilers. Analyzed the relationship between deNO x efficiency and characteristics of SCR DeNO x catalyst. Through analysis, affecting SCR DeNO x catalyst failure factors, change law of catalytic properties and technical measures to extend the service life of the catalyst were gotten. (author)

Wood burning stoves and small boilers - particle emissions and reduction initiatives; Braendeovne og smae kedler - partikelemissioner og reduktionstiltag

Energy Technology Data Exchange (ETDEWEB)

Illerup, J B; Capral Henriksen, T; Lundhede, T [Danmarks Miljoeundersoegelser, Aarhus Universitet, Aarhus (Denmark); Breugel, C van; Zoellner Jensen, N [Miljoestyrelsen, Copenhagen (Denmark)

2007-06-15

Pollution from burning wood in private households, and the environmental and health consequences of this is determined in practice by a complicated interaction between a number of factors, including firing habits, fuel, type of stove/boiler, chimney and location of the chimney in relation to the surroundings. This report maps out the technologies used today for burning wood in private households, how these technologies contribute to particle emissions and which technologies may potentially reduce emissions of particles from burning wood in households in Denmark. Moreover, the possible emissions reductions and the financial costs incurred by consumers from different initiatives have been estimated. This report does not deal with possible initiatives for improvement of firing habits, fuel quality and chimneys. (au)

Estimating the fuel moisture content to control the reciprocating grate furnace firing wet woody biomass

International Nuclear Information System (INIS)

Striūgas, N.; Vorotinskienė, L.; Paulauskas, R.; Navakas, R.; Džiugys, A.; Narbutas, L.

2017-01-01

Highlights: • Combustion of biomass with varying moisture content might lead to unstable operation of a furnace. • Method for automatic control of a furnace fired with wet biomass was developed. • Fuel moisture is estimated by cost-effective indirect method for predictive control. • Fuel moisture estimation methods and furnace control algorithm were validated in an industrial boiler. - Abstract: In small countries like Lithuania with a widespread district heating system, 5–10 MW moving grate biomass furnaces equipped with water boilers and condensing economisers are widely used. Such systems are designed for firing biomass fuels; however, varying fuel moisture, mostly in the range from 30% to 60%, complicates the automated operation. Without manual adjustment of the grate motion mode and other parameters, unstable operation or even extinction of the furnace is possible. To ensure stable furnace operation with moist fuel, the indirect method to estimate the fuel moisture content was developed based on the heat balance of the flue gas condensing economiser. The developed method was implemented into the automatic control unit of the furnace to estimate the moisture content in the feedstock and predictively adjust the furnace parameters for optimal fuel combustion. The indirect method based on the economiser heat balance was experimentally validated in a 6 MW grate-fired furnace fuelled by biomass with moisture contents of 37, 46, 50, 54 and 60%. The analysis shows that the estimated and manually measured values of the fuel moisture content do not differ by more than 3%. This deviation indicates that the indirect fuel moisture calculation method is sufficiently precise and the calculated moisture content varies proportionally to changes in the thermal capacity of the economiser. By smoothing the data using sliding weighted averaging, the oscillations of the fuel moisture content were identified.

Introduction of low-temperature swirl technology of burning as a way of increase in ecological of low power boilers

Science.gov (United States)

Trinchenko, A. A.; Paramonov, A. P.

2017-10-01

Work is devoted to the solution of problems of energy efficiency increase in low power boilers at combustion of solid fuel. The technological method of nitrogen oxides decomposition on a surface of carbon particles with education environmentally friendly carbonic acid and molecular nitrogen is considered during the work of a low-temperature swirl fire chamber. Based on the analysis of physical and chemical processes of a fuel chemically connected energy transition into thermal, using the diffusive and kinetic theory of burning modern approaches the technique, mathematical model and the settlement program for assessment of plant ecological indicators when using a new method are developed. Alternative calculations of furnace process are carried out, quantitative assessment of nitrogen oxides emissions level of the reconstructed boiler is executed. The results of modeling and experimental data have approved that the organization of swirl burning increases overall performance of a fire chamber and considerably reduces emissions of nitrogen oxides.

The effect of water jet lancing on furnace wall tubes of high slagged deposit fuel-fired boilers

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, V V; Kovalevitch, I A; Maidanik, M N [All-Union Heat Engineering Institute, Siberian Branch, Krasnoyarsk (USSR)

1990-01-01

In this paper the results of investigating the effectiveness of water jet lancing on furnace wall tubes of slagged deposits fuels fired boilers type E-500, P-64, P-67 are given. The boilers of these types are designed to burn Jugoslavian lignites are Beresovo lignites of the Kansk-Achinsk deposits. Recommendations for usage of low retractable, long retractable and long-range water blowers, depending on the design, produced in the USSR, the furnace dimension and stability of deposits are given as well.

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

Energy Technology Data Exchange (ETDEWEB)

Rissler, Jenny; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology

2005-02-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K{sub 2}SO{sub 4}, and K{sub 2}CO{sub 3}). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be {approx}2.5.

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

International Nuclear Information System (INIS)

Rissler, Jenny; Swietlicki, Erik; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Strand, Michael; Lillieblad, Lena; Sanati, Mehri

2005-01-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K 2 SO 4 , and K 2 CO 3 ). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be ∼2.5

An emissions audit of a chain grate stoker burning shredded tyres

International Nuclear Information System (INIS)

Jackson, P.M.; Jones, H.H.; King, P.G.

1993-01-01

This report describes the Emissions Audit carried out on a chain-grate stoker shell boiler burning shredded tyres at the Byker Heat Station. The unit has a thermal output of 5.75 MW. At the time of the audit the unit had no pollution abatement equipment fitter other than a cyclone grit arrestor. Combustion gas concentrations were good with test averages of CO and THC at -3 and -3 respectively. CO 2 and O 2 concentrations were steady throughout both tests. However, improvements in CO concentrations could be achieved by further optimisation. Acid gas concentrations were relatively steady throughout the test periods, the dominant gas being SO 2 at about 1450 mgm -3 . There are at present no concentration guidelines for SO 2 emissions for a unit of this size, however, the concentrations were well in excess of guidelines for units burning more than one tonne per hour of tyres. HCl concentrations at -3 were well below the guidelines, a reflection of the low Cl content of tyres. (Author)

Computational fluid dynamic simulations of coal-fired utility boilers: An engineering tool

Energy Technology Data Exchange (ETDEWEB)

Efim Korytnyi; Roman Saveliev; Miron Perelman; Boris Chudnovsky; Ezra Bar-Ziv [Ben-Gurion University of the Negev, Beer-Sheva (Israel)

2009-01-15

The objective of this study was to develop an engineering tool by which the combustion behavior of coals in coal-fired utility boilers can be predicted. We presented in this paper that computational fluid dynamic (CFD) codes can successfully predict performance of - and emission from - full-scale pulverized-coal utility boilers of various types, provided that the model parameters required for the simulation are properly chosen and validated. For that purpose we developed a methodology combining measurements in a 50 kW pilot-scale test facility with CFD simulations using the same CFD code configured for both test and full-scale furnaces. In this method model parameters of the coal processes are extracted and validated. This paper presents the importance of the validation of the model parameters which are used in CFD codes. Our results show very good fit of CFD simulations with various parameters measured in a test furnace and several types of utility boilers. The results of this study demonstrate the viability of the present methodology as an effective tool for optimization coal burning in full-scale utility boilers. 41 refs., 9 figs., 3 tabs.

Efficient boiler operations sourcebook

Energy Technology Data Exchange (ETDEWEB)

Payne, F.W. (comp.)

1985-01-01

This book emphasizes the practical aspects of industrial and commercial boiler operations. It starts with a comprehensive review of general combustion and boiler fundamentals and then deals with specific efficiency improvement methods, and the cost savings which result. The book has the following chapter headings: boiler combustion fundamentals; boiler efficiency goals; major factors controlling boiler efficiency; boiler efficiency calculations; heat loss; graphical solutions; preparation for boiler testing; boiler test procedures; efficiency-related boiler maintenance procedures; boiler tune-up; boiler operational modifications; effect of water side and gas side scale deposits; load management; auxillary equipment to increase boiler efficiency; air preheaters and economizers; other types of auxillary equipment; combustion control systems and instrumentation; boiler O/sub 2/ trim controls; should you purchase a new boiler.; financial evaluation procedures; case studies. The last chapter includes a case study of a boiler burning pulverized coal and a case study of stoker-fired coal.

Characteristics of particulate-bound polycyclic aromatic hydrocarbons emitted from industrial grade biomass boilers.

Science.gov (United States)

Yang, Xiaoyang; Geng, Chunmei; Sun, Xuesong; Yang, Wen; Wang, Xinhua; Chen, Jianhua

2016-02-01

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic or mutagenic and are important toxic pollutants in the flue gas of boilers. Two industrial grade biomass boilers were selected to investigate the characteristics of particulate-bound PAHs: one biomass boiler retro-fitted from an oil boiler (BB1) and one specially designed (BB2) biomass boiler. One coal-fired boiler was also selected for comparison. By using a dilution tunnel system, particulate samples from boilers were collected and 10 PAH species were analyzed by gas chromatography-mass spectrometry (GC-MS). The total emission factors (EFs) of PAHs ranged from 0.0064 to 0.0380 mg/kg, with an average of 0.0225 mg/kg, for the biomass boiler emission samples. The total PAH EFs for the tested coal-fired boiler were 1.8 times lower than the average value of the biomass boilers. The PAH diagnostic ratios for wood pellets and straw pellets were similar. The ratio of indeno(1,2,3-cd)pyrene/[indeno(1,2,3-cd)pyrene+benzo(g,h,i)perylene] for the two biomass boilers was lower than those of the reference data for other burning devices, which can probably be used as an indicator to distinguish the emission of biomass boilers from that of industrial coal-fired boilers and residential stoves. The toxic potential of the emission from wood pellet burning was higher than that from straw pellet burning, however both of them were much lower than residential stove exhausts. Copyright © 2015. Published by Elsevier B.V.

GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS

Energy Technology Data Exchange (ETDEWEB)

Nsakala ya Nsakala; Gregory N. Liljedahl

2003-05-15

Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB units results in significant Boiler Island cost savings. Additionally, ALSTOM has identified several advanced/novel plant configurations, which improve the efficiency and cost of the CO{sub 2} product cleanup and compression process. These advanced/novel concepts require long development efforts. An economic analysis indicates that the proposed oxygen-firing technology in circulating fluidized boilers could be developed and deployed economically in the near future in enhanced oil recovery (EOR) applications or enhanced gas recovery (EGR), such as coal bed methane recovery. ALSTOM received a Cooperative Agreement from the US

Low NO{sub x} burner modifications to front-fired pulverized coal boilers

Energy Technology Data Exchange (ETDEWEB)

Broderick, R G; Wagner, M

1998-07-01

Madison Gas and Electric Blount Street Station Units 8 and 9 are Babcock and Wilcox pulverized coal fired and natural gas fired boilers. These boilers were build in the late 1950's and early 1960's with each boiler rated at 425,000 lb./hr of steam producing 50 MW of electricity. The boilers are rated at 9,500 F at 1,350 psig. Each unit is equipped with one Ljungstroem air heater and two B and W EL pulverizers. These units burn subbituminous coal with higher heating value of 10,950 Btu/LB on an as-received basis. The nitrogen content is approximately 1.23% with 15% moisture. In order to comply with the new Clean Air Act Madison Gas and Electric needs to reduce NO{sub x} on these units to less than .5 LB/mmBtu. Baseline NO{sub x} emissions on these units range between .8--.9 lb./mmBtu. LOIs average approximately 8%. Madison Gas and Electric contracted with RJM Corporation to modify the existing burners to achieve this objective. These modifications consisted of adding patented circumferentially and radially staged flame stabilizers, modifying the coal pipe, and replacing the coal impeller with a circumferentially staged coal spreader. RJM Corporation utilized computational fluid dynamics modeling in order to design the equipment to modify these burners. The equipment was installed during the March 1997 outage and start-up and optimization was conducted in April 1997. Final performance results and economic data will be included in the final paper.

40 CFR 270.22 - Specific part B information requirements for boilers and industrial furnaces burning hazardous...

Science.gov (United States)

2010-07-01

... requirements for boilers and industrial furnaces burning hazardous waste. 270.22 Section 270.22 Protection of... requirements for boilers and industrial furnaces burning hazardous waste. When an owner or operator of a cement kiln, lightweight aggregate kiln, solid fuel boiler, liquid fuel boiler, or hydrochloric acid...

Research, Development and Demonstration of Bio-Mass Boiler for Food Industry

Energy Technology Data Exchange (ETDEWEB)

Fisher, Steve [Burns & McDonnell, Inc., Kansas City, MO (United States); Knapp, David [Burns & McDonnell, Inc., Kansas City, MO (United States)

2012-07-01

Frito-Lay is working to reduce carbon emissions from their manufacturing plants. As part of this effort, they invested in a biomass-fired boiler at the Topeka, Kansas, plant. Frito-Lay partnered with Burns & McDonnell Engineering, Inc. and CPL Systems, Inc., to design and construct a steam producing boiler using carbon neutral fuels such as wood wastes (e.g. tree bark), shipping pallets, and used rubber vehicle tires. The U.S. Department of Energy (DOE) joined with Frito-Lay, Burns & McDonnell, and CPL to analyze the reductions in carbon dioxide (CO₂) emissions that result from use of biomass-fired boilers in the food manufacturing environment. DOE support provided for the data collection and analysis, and reporting necessary to evaluate boiler efficiencies and reductions in CO₂ emissions. The Frito-Lay biomass-fired boiler has resulted in significant reductions in CO₂ emissions from the Topeka production facility. The use of natural gas has been reduced by 400 to 420 million standard cubic feet per year with corresponding reductions of 24,000 to 25,000 tons of CO₂. The boiler does require auxiliary functions, however, that are unnecessary for a gas-fired boiler. These include heavy motors and fans for moving fuel and firing the boiler, trucks and equipment for delivering the fuel and moving at the boiler plant, and chippers for preparing the fuel prior to delivery. Each of these operations requires the combustion of fossil fuels or electricity and has associated CO₂ emissions. Even after accounting for each of these auxiliary processes, however, the biomass-fired boiler results in net emission reductions of 22,500 to 23,500 tons of CO₂ per year.

Global Burned Area and Biomass Burning Emissions from Small Fires

Science.gov (United States)

Randerson, J. T.; Chen, Y.; vanderWerf, G. R.; Rogers, B. M.; Morton, D. C.

2012-01-01

In several biomes, including croplands, wooded savannas, and tropical forests, many small fires occur each year that are well below the detection limit of the current generation of global burned area products derived from moderate resolution surface reflectance imagery. Although these fires often generate thermal anomalies that can be detected by satellites, their contributions to burned area and carbon fluxes have not been systematically quantified across different regions and continents. Here we developed a preliminary method for combining 1-km thermal anomalies (active fires) and 500 m burned area observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate the influence of these fires. In our approach, we calculated the number of active fires inside and outside of 500 m burn scars derived from reflectance data. We estimated small fire burned area by computing the difference normalized burn ratio (dNBR) for these two sets of active fires and then combining these observations with other information. In a final step, we used the Global Fire Emissions Database version 3 (GFED3) biogeochemical model to estimate the impact of these fires on biomass burning emissions. We found that the spatial distribution of active fires and 500 m burned areas were in close agreement in ecosystems that experience large fires, including savannas across southern Africa and Australia and boreal forests in North America and Eurasia. In other areas, however, we observed many active fires outside of burned area perimeters. Fire radiative power was lower for this class of active fires. Small fires substantially increased burned area in several continental-scale regions, including Equatorial Asia (157%), Central America (143%), and Southeast Asia (90%) during 2001-2010. Globally, accounting for small fires increased total burned area by approximately by 35%, from 345 Mha/yr to 464 Mha/yr. A formal quantification of uncertainties was not possible, but sensitivity

Multi-objective Optimization of Coal-fired Boiler Combustion Based on NSGA-II

OpenAIRE

Tingfang Yu; Hongzhen Zhu; Chunhua Peng

2013-01-01

NOx emission characteristics and overall heat loss model for a 300MW coal-fired boiler were established by Back Propagation (BP) neural network, by which the the functional relationship between outputs (NOx emissions & overall heat loss of the boiler) and inputs (operational parameters of the boiler) of a coal-fired boiler can be predicted. A number of field test data from a full-scale operating 300MWe boiler were used to train and verify the BP model. The NOx emissions & heat loss pr...

Exergetic Modelling of Oil-Fired Steam Boilers | Ohijeagbon ...

African Journals Online (AJOL)

The performance variables and potential for energy savings in oil-fired industrial steam boilers were studied. Operational parameters of steam boilers using low pour fuel oil (LPFO) and diesel were used to determine thermodynamic properties of material streams and exergetic parameters. Analysis of thermodynamic ...

Co-firing of Coal with Biomass and Waste in Full-scale Suspension-fired Boilers

DEFF Research Database (Denmark)

Dam-Johansen, Kim; Jappe Frandsen, Flemming; Jensen, Peter Arendt

2013-01-01

and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools....... The research conducted has addressed many issues important for co-firing, i.e. fuel processing, ash induced boiler deposit formation and corrosion, boiler chamber fuel conversion and emission formation, influence on flue gas cleaning equipment and the utilization of residual products. This paper provides...... research has provided results with implications for operation of milling and burner equipment, appropriate fuel mixing strategies, minimization of ash deposit formation and corrosion, minimization of NO formation, appropriate operation of SCR catalyst equipment and utilization of residual products...

46 CFR 52.01-35 - Auxiliary, donkey, fired thermal fluid heater, and heating boilers.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Auxiliary, donkey, fired thermal fluid heater, and... (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-35 Auxiliary, donkey, fired thermal... requirements for miscellaneous boiler types, such as donkey, fired thermal fluid heater, heating boiler, etc...

Characterization and quantification of deposits build up and removal in straw suspension fired boilers

DEFF Research Database (Denmark)

Jensen, Peter Arendt; Shafique Bashir, Muhammad; Wedel, Stig

This project deals with ash deposit formation in suspension fired biomass power plant boilers. The project has been conducted in a tight collaboration between Vattenfall and the CHEC Research Centre at DTU Department of Chemical Engineering. A large part of the project has been performed by condu......This project deals with ash deposit formation in suspension fired biomass power plant boilers. The project has been conducted in a tight collaboration between Vattenfall and the CHEC Research Centre at DTU Department of Chemical Engineering. A large part of the project has been performed...... by conducting advanced probe measurements at the Amagerværkets Vattenfall owed boilers. It was the objective of the project to provide an improved understanding of ash deposit formation and removal in biomass suspension fired boilers. The project have provided a large amount of knowledge on the following issues......: 1) The influence of local boiler conditions on deposit formation in suspension fired boilers using wood or co-firing straw and wood, 2) quantification of deposit removal in biomass suspension firing boilers with regards both to natural shedding and soot blower induced shedding, 3) established...

Influence of declivitous secondary air on combustion characteristics of a down-fired 300-MWe utility boiler

Energy Technology Data Exchange (ETDEWEB)

Zhengqi Li; Feng Ren; Zhichao Chen; Zhao Chen; Jingjie Wang [Harbin Institute of Technology, Harbin (China). School of Energy Science and Engineering

2010-02-15

Industrial experiments were performed with a 300-MWe full-scale down-fired boiler. New data is reported for (i) gas temperature distributions within the primary air and coal mixture flows, (ii) gas compositions, such as O{sub 2}, CO, CO{sub 2} and NOx, and (iii) gas temperatures within the near-wall region. The data complements previously-obtained data from the same utility boiler before being modified by declination of the F-tier secondary air. By directing secondary air under the arches, the region where the primary air and pulverized coal mixture is ignited is brought forward within the boiler. Gas temperatures rose in the fuel-burning zone and fell in the fuel-burnout zone. As a result the quantity of unburned carbon in fly ash and the gas temperature at the furnace outlet were both lowered. 20 refs., 7 figs., 2 tabs.

Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Adams, Bradley [Univ. of Utah, Salt Lake City, UT (United States); Davis, Kevin [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shim [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Eddings, Eric [Univ. of Utah, Salt Lake City, UT (United States); Paschedag, Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cox, William [Brigham Young Univ., Provo, UT (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

2013-09-30

Reaction Engineering International (REI) managed a team of experts from University of Utah, Siemens Energy, Praxair, Vattenfall AB, Sandia National Laboratories, Brigham Young University (BYU) and Corrosion Management Ltd. to perform multi-scale experiments, coupled with mechanism development, process modeling and CFD modeling, for both applied and fundamental investigations. The primary objective of this program was to acquire data and develop tools to characterize and predict impacts of CO{sub 2} flue gas recycle and burner feed design on flame characteristics (burnout, NO{sub x}, SO{sub x}, mercury and fine particle emissions, heat transfer) and operational concerns (fouling, slagging and corrosion) inherent in the retrofit of existing coal-fired boilers for oxy-coal combustion. Experimental work was conducted at Sandia National Laboratories’ Entrained Flow Reactor, the University of Utah Industrial Combustion Research Facility, and Brigham Young University. Process modeling and computational fluid dynamics (CFD) modeling was performed at REI. Successful completion of the project objectives resulted in the following key deliverables: 1) Multi-scale test data from 0.1 kW bench-scale, 100 kW and 200 kW laboratory-scale, and 1 MW semi-industrial scale combustors that describe differences in flame characteristics, fouling, slagging and corrosion for coal combustion under air-firing and oxygen-firing conditions, including sensitivity to oxy-burner design and flue gas recycle composition. 2) Validated mechanisms developed from test data that describe fouling, slagging, waterwall corrosion, heat transfer, char burnout and sooting under coal oxy-combustion conditions. The mechanisms were presented in a form suitable for inclusion in CFD models or process models. 3) Principles to guide design of pilot-scale and full-scale coal oxy-firing systems and flue gas recycle configurations, such that boiler operational impacts from oxy-combustion retrofits are minimized. 4

Biomass co-firing

DEFF Research Database (Denmark)

Yin, Chungen

2013-01-01

Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized-bed combus......Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized......-bed combustion (FBC) systems, and grate-firing systems, which are employed in about 50%, 40% and 10% of all the co-firing plants, respectively. Their basic principles, process technologies, advantages, and limitations are presented, followed by a brief comparison of these technologies when applied to biomass co...

Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature

Energy Technology Data Exchange (ETDEWEB)

Saqib, Naeem, E-mail: naeem.saqib@oru.se; Bäckström, Mattias, E-mail: mattias.backstrom@oru.se

2014-12-15

Highlights: • Different solids waste incineration is discussed in grate fired and fluidized bed boilers. • We explained waste composition, temperature and chlorine effects on metal partitioning. • Excessive chlorine content can change oxide to chloride equilibrium partitioning the trace elements in fly ash. • Volatility increases with temperature due to increase in vapor pressure of metals and compounds. • In Fluidized bed boiler, most metals find themselves in fly ash, especially for wood incineration. - Abstract: Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine

Co-firing Coal and Straw in a 150 MWe Utility Boiler: Deposition Propensities

DEFF Research Database (Denmark)

Andersen, Karin Hedebo; Hansen, Peter Farkas Binderup; Wieck-Hansen, Kate

1996-01-01

In order to meet a 20 % reduction in CO2 emissions, based on 1988 levels, by the year 2005, the Danish Government has committed the power companies in Denmark to burn 1.2 million tons of straw per year from the year 2000. A conventional pf-fired boiler at the Danish Power Company Midtkraft has been...... on temperature controlled probes and in-situ measurements of flue gas temperature, flue gas compositions including alkali metal concentrations and particle and aerosol loading and composition. The study is carried out as collaborative research projects between the Midtkraft Power Company and the Combustion...

Analysis of residual swirl in tangentially-fired natural gas-boiler

International Nuclear Information System (INIS)

Hasril Hasini; Muhammad Azlan Muad; Mohd Zamri Yusoff; Norshah Hafeez Shuaib

2010-01-01

This paper describes the investigation on residual swirl flow in a 120 MW natural gas, full-scale, tangential-fired boiler. Emphasis is given towards the understanding of the behavior of the combustion gas flow pattern and temperature distribution as a result of the tangential firing system of the boiler. The analysis was carried out based on three-dimensional computational modeling on full scale boiler with validation from key design parameter as well as practical observation. Actual operating parameters of the actual boiler are taken as the boundary conditions for this modeling. The prediction of total heat flux was found to be in agreement with the key design parameter while the residual swirl predicted at the upper furnace agrees qualitatively with the practical observation. Based on this comparison, detail analysis was carried out for comprehensive understanding on the generation and destruction of the residual swirl behavior in boiler especially those with high capacity. (author)

Regulation of hazardous air pollutants emitted from fossil-fired boilers

International Nuclear Information System (INIS)

Hendrickson, P.L.; Daellenbach, K.K.

1993-01-01

The changes made in section 112 of the Clean Air Act by the 1990 Amendments to the Act will affect the regulation of hazardous air pollutants (HAPs) emitted by fossil-fired boilers. The 1990 Amendments designated 189 chemicals/compounds as HAPS. Major and area sources of these pollutants in categories designated by the Environmental Protection Agency (EPA) will be subject to emission standards set by EPA. Industrial and institutional/commercial boilers are two such categories of HAPs designated by EPA for which emission standards will be issued. Fossil-fired boilers can emit a variety of HAPS. All or a portion of such emissions that exceed designated thresholds are likely to be regulated. This paper discusses how the 1990 amendments impact fossil-fired boilers. The steps are outlined which can be taken by owners of industrial and institutional/commercial boilers before the final emission standards are issued. These steps include participation in EPA's standard setting process, participation in EPA's early reduction program to delay the time when compliance with the maximum achievable control technology (MACT) standard is required, and consideration of any planned modifications to a facility which might subject that facility to a MACT standard set in advance of the EPA-set standard

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

International Nuclear Information System (INIS)

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

2001-01-01

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

Emissions from three wood-fired domestic central heating boilers - heat load dependence

International Nuclear Information System (INIS)

Karlsson, M.L.

1992-01-01

The flue gases from three wood-fired domestic central heating boilers have been characterized. Measurements were made at three part loads; 3, 7 and 15 kW. Two of the boilers were modern multi-fuel boilers, with inverse firing and natural draught. The third boiler was a single-fuel wood boiler, with inverse firing and combustion air supply through a fan. All boilers were environmentally approved; the tar emissions were below 30 mg/MJ at nominal heat load. The following parameters were measured: - CO, CO 2 , NO x , total hydrocarbons (THC), - tar and particulates, - twelve volatile organic compounds (VOC). The limit value for tar emission was heavily exceeded for all three boilers at the part loads at which they were tested. For the two multi-fuel boilers the tar emissions decreased with increasing load level, while the opposite was found for the wood boiler with a fan. The NO x emissions varied between 20 and 120 mg/MJ. The multi-fuel boilers showed increasing NO x emissions with increasing heat load. The single-fuel wood boiler showed NO x emissions at about 60 mg/MJ, independent of load level. The CO and THC levels in general were high. The CO levels varied between 1000 and 2000 mg/MJ. While the THC levels varied between 300 and 4000 mg/MJ. Broadly speaking, the CO and THC levels decreased with increasing load levels for the multi-fuel boilers. For the single-fuel wood boiler the CO and THC levels were roughly the same at all load levels. Out of the twelve VOC compounds which were measured, the following could be detected and quantified. With FTIR analysis: Methane, ethylene, propene and acetylene. With GC analysis: Methanol, phenol and acetic acid. (1 ref., 31 figs., 7 tabs.)

APPLICATION OF REBURNING TO COAL-FIRED INDUSTRIAL BOILERS IN TAIWAN

Science.gov (United States)

The paper gives an overview of the characteristics of coal-fired industrial boilers in Taiwan and projections of the cost and performance data for retrofitting several boilers with reburning. The impacts of reburning fuel type on the reburning system design and cost effectivenes...

A novel direct-fired porous-medium boiler

Science.gov (United States)

Prasartkaew, Boonrit

2018-01-01

Nowadays, power and heat generation systems pay an important role in all economic sectors. These systems are mainly based on combustion reaction and operated under the second law of thermodynamics. A conventional boilers, a main component of heat and power generators, have thermal efficiency in the range of 70 to 85%, mainly owing to they have flue gas heat loss. This paper proposes a novel type of boiler, called a Direct-fired Porous-medium Boiler (DPB). Due to being operated without flue gas heat loss, its thermal efficiency cloud be approximately close to 100%. The steam produced from the proposed boiler; however, is not pure water steam. It is the composite gases of steam and combustion-product-gases. This paper aims at presenting the working concept and reporting the experimental results on the performance of the proposed boiler. The experiments of various operating parameters were performed and collected data were used for the performance analysis. The experimental results demonstrated that the proposed boiler can be operated as well as the conceptual design and then it is promising. It can be possibly further developed to be a high efficiency boiler by means of reducing or suppressing the surface heat loss with better insulator and/or refractory lined.

Biomass Cofiring in Coal-Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

2004-06-01

Cofiring biomass-for example, forestry residues such as wood chips-with coal in existing boilers is one of the easiest biomass technologies to implement in a federal facility. The current practice is to substitute biomass for up to 20% of the coal in the boiler. Cofiring has many benefits: it helps to reduce fuel costs as well as the use of landfills, and it curbs emissions of sulfur oxide, nitrogen oxide, and the greenhouse gases associated with burning fossil fuels. This Federal Technology Alert was prepared by the Department of Energy's Federal Energy Management Program to give federal facility managers the information they need to decide whether they should pursue biomass cofiring at their facilities.

Oil fired boiler/solar tank- and natural gas burner/solar tank-units

DEFF Research Database (Denmark)

Furbo, Simon; Vejen, Niels Kristian; Frederiksen, Karsten Vinkler

1999-01-01

During the last few years new units consisting of a solar tank and either an oil fired boiler or a natural gas burner have been introduced on the Danish market. Three different marketed units - two based on a natural gas burner and one based on an oil fired boiler - have been tested in a heat...

Innovative clean coal technology (ICCT): demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emission from high-sulfur, coal-fired boilers - economic evaluation of commercial-scale SCR applications for utility boilers

International Nuclear Information System (INIS)

Healy, E.C.; Maxwell, J.D.; Hinton, W.S.

1996-09-01

This report presents the results of an economic evaluation produced as part of the Innovative Clean Coal Technology project, which demonstrated selective catalytic reduction (SCR) technology for reduction of NO x emissions from utility boilers burning U.S. high-sulfur coal. The document includes a commercial-scale capital and O ampersand M cost evaluation of SCR technology applied to a new facility, coal-fired boiler utilizing high-sulfur U.S. coal. The base case presented herein determines the total capital requirement, fixed and variable operating costs, and levelized costs for a new 250-MW pulverized coal utility boiler operating with a 60-percent NO x removal. Sensitivity evaluations are included to demonstrate the variation in cost due to changes in process variables and assumptions. This report also presents the results of a study completed by SCS to determine the cost and technical feasibility of retrofitting SCR technology to selected coal-fired generating units within the Southern electric system

A study of burning processes of fossil fuels in straitened conditions of furnaces in low capacity boilers by an example of natural gas

Science.gov (United States)

Roslyakov, P. V.; Proskurin, Y. V.; Khokhlov, D. A.; Zaichenko, M. N.

2018-03-01

The aim of this work is to research operations of modern combined low-emission swirl burner with a capacity of 2.2 MW for fire-tube boiler type KV-GM-2.0, to ensure the effective burning of natural gas, crude oil and diesel fuel. For this purpose, a computer model of the burner and furnace chamber has been developed. The paper presents the results of numerical investigations of the burner operation, using the example of natural gas in a working load range from 40 to 100%. The basic features of processes of fuel burning in the cramped conditions of the flame tube have been identified to fundamentally differ from similar processes in the furnaces of steam boilers. The influence of the design of burners and their operating modes on incomplete combustion of fuel and the formation of nitrogen oxides has been determined.

Performance of a pellet boiler fired with agricultural fuels

International Nuclear Information System (INIS)

Carvalho, Lara; Wopienka, Elisabeth; Pointner, Christian; Lundgren, Joakim; Verma, Vijay Kumar; Haslinger, Walter; Schmidl, Christoph

2013-01-01

Highlights: ► Performance evaluation of a pellet boiler operated with different agricultural fuels. ► Agricultural fuels could be burn in the tested boiler for a certain period of time. ► All the fuels (except straw and Sorghum) satisfied the European legal requirements. ► Boilers for burning agricultural fuels should have a flexible control system. - Abstract: The increasing demand for woody biomass increases the price of this limited resource, motivating the growing interest in using woody materials of lower quality as well as non-woody biomass fuels for heat production in Europe. The challenges in using non-woody biomass as fuels are related to the variability of the chemical composition and in certain fuel properties that may induce problems during combustion. The objective of this work has been to evaluate the technical and environmental performance of a 15 kW pellet boiler when operated with different pelletized biomass fuels, namely straw (Triticum aestivum), Miscanthus (Miscanthus × giganteus), maize (Zea mays), wheat bran, vineyard pruning (from Vitis vinifera), hay, Sorghum (Sorghum bicolor) and wood (from Picea abies) with 5% rye flour. The gaseous and dust emissions as well as the boiler efficiency were investigated and compared with the legal requirements defined in the FprEN 303-5 (final draft of the European standard 303-5). It was found that the boiler control should be improved to better adapt the combustion conditions to the different properties of the agricultural fuels. Additionally, there is a need for a frequent cleaning of the heat exchangers in boilers operated with agricultural fuels to avoid efficiency drops after short term operation. All the agricultural fuels satisfied the legal requirements defined in the FprEN 303-5, with the exception of dust emissions during combustion of straw and Sorghum. Miscanthus and vineyard pruning were the best fuels tested showing comparable emission values to wood combustion

Application of Coal Thermal Treatment Technology for Oil-Free Firing of Boilers

Science.gov (United States)

Aliyarov, B.; Mergalimova, A.; Zhalmagambetova, U.

2018-04-01

The theoretical and practical introduction of this kind of firing boiler units in coal thermal power plants is considered in the article. The results of an experimental study of three types of coals are presented in order to obtain the required gaseous fuel. The aim of the study is to develop a new, economically and ecologically more acceptable method for firing boilers at thermal power plants, which is able to exclude the use of expensive and inconvenient fuel oil. The tasks of the experiment are to develop a technological scheme of kindling of boilers at thermal power plants, using as a type of ignition fuel volatile combustible substances released during the heating of coal, and to investigate three types of coal for the suitability of obtaining gaseous fuels, in sufficient volume and with the required heat of combustion. The research methods include the analysis of technical and scientific-methodological literature on the problem of the present study, the study of the experience of scientists of other countries, the full-scale experiment on the production of volatile combustible substances. During the full-scale experiment, the coal of 3 fields of Kazakhstan has been studied: Shubarkul, Maikuben and Saryadyr. The analysis has been performed and the choice of the most convenient technology for boiler kindling and maintenance of steady burning of the torch has been made according to the proposed method, as well as the corresponding technological scheme has been developed. As a result of the experiment, it can be stated that from coal in the process of its heating (without access to oxygen), it is possible to obtain a sufficient amount of combustible volatile substances. The released gaseous fuel has the necessary parameters and is quite capable of replacing an expensive fuel oil. The resulting gaseous fuel is quite convenient to use and environmentally cleaner. The piloting scheme developed as a result of the experiment can be introduced in pulverized

Advanced In-Furnace NOx Control for Wall and Cyclone-Fired Boilers

International Nuclear Information System (INIS)

Sarv, Hamid

2009-01-01

A NO x minimization strategy for coal-burning wall-fired and cyclone boilers was developed that included deep air staging, innovative oxygen use, reburning, and advanced combustion control enhancements. Computational fluid dynamics modeling was applied to refine and select the best arrangements. Pilot-scale tests were conducted by firing an eastern high-volatile bituminous Pittsburgh No.8 coal at 5 million Btu/hr in a facility that was set up with two-level overfire air (OFA) ports. In the wall-fired mode, pulverized coal was burned in a geometrically scaled down version of the B and W DRB-4Z(reg sign) low-NO x burner. At a fixed overall excess air level of 17%, NO x emissions with single-level OFA ports were around 0.32 lb/million Btu at 0.80 burner stoichiometry. Two-level OFA operation lowered the NO x levels to 0.25 lb/million Btu. Oxygen enrichment in the staged burner reduced the NO x values to 0.21 lb/million Btu. Oxygen enrichment plus reburning and 2-level OFA operation further curbed the NO x emissions to 0.19 lb/million Btu or by 41% from conventional air-staged operation with single-level OFA ports. In the cyclone firing arrangement, oxygen enrichment of the cyclone combustor enabled high-temperature and deeply staged operation while maintaining good slag tapping. Firing the Pittsburgh No.8 coal in the optimum arrangement generated 112 ppmv NO x (0.15 lb/million Btu) and 59 ppmv CO. The optimum emissions results represent 88% NO x reduction from the uncontrolled operation. Levelized costs for additional NO x removal by various in-furnace control methods in reference wall-fired or cyclone-fired units already equipped with single-level OFA ports were estimated and compared with figures for SCR systems achieving 0.1 lb NO x /10 6 Btu. Two-level OFA ports could offer the most economical approach for moderate NO x control, especially for smaller units. O 2 enrichment in combination with 2-level OFA was not cost effective for wall-firing. For cyclone units

Control Properties of Bottom Fired Marine Boilers

DEFF Research Database (Denmark)

Solberg, Brian; Andersen, Palle; Karstensen, Claus M. S.

2005-01-01

This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearised versions of the model are analysed to determine how gain, time constants and right half plane zeros (caused by the shrink-and-swell phenomenon) depend on the steam flow load. Furthermore...... the interactions in the system are inspected to analyse potential benefit from using a multivariable control strategy in favour of the current strategy based on single loop theory. An analysis of the nonlinear model is carried out to further determine the nonlinear characteristics of the boiler system...

Development of a dynamic drying model for for a combustion grate; Framtagande av en dynamisk torkmodell foer en foerbraenningsrost

Energy Technology Data Exchange (ETDEWEB)

Broden, Henrik; Ramstroem, Erik [TPS Termiska Processer AB, Nykoeping (Sweden)

2005-02-01

Combustion of wet wood fuel at high grate loading requires good control of the burnout position to avoid unacceptably high content of unburnt fuel in the ash. To control the burn-out position, control actions on the grate feeding must be made with sufficient range and anticipation. One way to improve the understanding of the dynamic fuel bed response on changes in control system parameters is mathematical modelling. The research task has been to develop a mathematical model of a drying fuel bed on a moving grate. The model includes a simplified description of drying, pyrolysis and char combustion and also pusher/grate movement and primary air flow/distribution. The objectives of the project have been to establish the most likely mechanism for drying and ignition of a wet fuel bed on a moving grate by the use of mathematical modelling and also to create a tool for simulation of control system step responses. The target group for the project are individuals working in the area of control system development of grate fired boilers. Three different assumptions on drying and ignition front propagation in a bio fuel bed with 50 and 53 % moisture have been modelled: 1. Drying and ignition from an underlying char layer in a co-current primary air flow 2. Drying and ignition from an overlaying char layer in counter-current primary air flow 3. Drying and ignition from both an underlying and overlaying char layer The model with drying and ignition driven by an underlying char layer is the projection, which gives the fastest and time-wise the most similar course to what one normally sees in grate fired boilers. The model with drying and ignition from above is not capable of upholding a stable diffusion controlled burning char layer since too small quantities of heat is transferred into the fuel bed. The model with drying and ignition from both directions results in similar combustion rate as the first model. The similar course of combustion is due to the energy for drying

Ash transformation in suspension fired boilers co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

To study the influence of local conditions on the reaction between gaseous KCl and kaolin or coal fly ash experiments were done on CHECs electrically heated entrained flow reactor, which can simulate the local conditions in suspension fired boilers. The experimental results were compared with mod...

Development and test of small-scale batch-fired straw boilers in Denmark

International Nuclear Information System (INIS)

Kristensen, E.F.; Kristensen, J.K.

2004-01-01

In Denmark, government subsidies for the testing and installation of biomass-fired boilers were available for the period from 1995 until 2002. Each boiler type had to pass an official approval test to achieve subsidy. The combustion abilities of the boiler were optimized prior to the test. The main aim of this subsidy was to encourage the development of energy-efficient and environmentally friendly boilers. The scheme was therefore organized in such a way that the greatest subsidies were awarded for boilers with high efficiency and low emissions. This goal has in effect been achieved for batch-fired straw boilers, where the typical efficiency has been increased from about 75% in 1995 to about 87% in 2002. Similarly, the carbon monoxide emissions have been reduced from 5000 ppm (reference value 10% O 2 ) in 1995 to less than 1000 ppm in 2002. These improvements are mainly due to better insulation inside the combustion chamber, more efficient techniques for supplying air to the combustion process, improved cooling of the flue gas, and optimization of the electronic control unit for the air supply

Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

Directory of Open Access Journals (Sweden)

Majid Asnavandi

2017-01-01

Full Text Available The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tubes is not uniform which suggests that fire-side corrosion has happened on the tubes. Fire-side corrosion is caused by the reaction of combustion products with oxide layers on the tube surface resulting in metal loss and consequently tubes fracture. However, the tubes corrosion behaviour did not follow the conventional models of the fire-side corrosion. Given that, using the corrosion monitoring techniques for these boiler tubes seems essential. As a result, the thickness of the boiler tubes in different parts of the boiler has been recorded and critical points are selected accordingly. Such critical points are selected for installation of corrosion monitoring probes.

Control Properties of Bottom Fired Marine Boilers

DEFF Research Database (Denmark)

Solberg, Brian; Andersen, Palle; Karstensen, Claus M. S.

2007-01-01

This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearized versions of the model are analyzed and show large variations in system gains at steady state as function of load whereas gain variations near the desired bandwidth are small. An analys...

Innovative coupling of cogeneration units with fire tube boilers: thermo-fluid dynamics of the fire tubes

Science.gov (United States)

Cioccolanti, L.; Arteconi, A.; Bartolini, C. M.; Polonara, F.

2017-11-01

Nowadays the thermal energy demand in the industrial sector is usually satisfied by means of fire tube boilers while electricity is supplied from the grid. Alternatively cogeneration units could be adopted for thermal and electrical energy self-production, whilst installing boilers only as back-up units. However, even when cogeneration is profitable, it is not widespread because industries are usually unwilling to accept cogeneration plants for reliability and high investment costs issues. In this work a system aimed at overcoming the above mentioned market difficulties is proposed. It consists of an innovative coupling of a combined heat and power unit with a modified fire tube boiler. In particular, a CFD analysis was carried out by the authors in order to address the most critical aspects related with the coupling of the two systems. More precisely, the following aspects were evaluated in detail: (i) pressure losses of the exhausts going from the prime mover to the boiler due to the sudden cross-section area variations; (ii) thermal power recoverable from the exhausts in the tubes of the boiler; (iii) dependence of the system on the final users’ specification.

NOx Control Options and Integration for US Coal Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Mike Bockelie; Marc Cremer; Kevin Davis; Martin Denison; Adel Sarofim; Connie Senior; Hong-Shig Shim; Dave Swenson; Bob Hurt; Eric Suuberg; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker

2006-06-30

This is the Final Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project was to develop cost-effective analysis tools and techniques for demonstrating and evaluating low-NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) provided co-funding for this program. This project included research on: (1) In furnace NOx control; (2) Impacts of combustion modifications on boiler operation; (3) Selective Catalytic Reduction (SCR) catalyst testing and (4) Ammonia adsorption/removal on fly ash. Important accomplishments were achieved in all aspects of the project. Rich Reagent Injection (RRI), an in-furnace NOx reduction strategy based on injecting urea or anhydrous ammonia into fuel rich regions in the lower furnace, was evaluated for cyclone-barrel and PC fired utility boilers. Field tests successfully demonstrated the ability of the RRI process to significantly reduce NOx emissions from a staged cyclone-fired furnace operating with overfire air. The field tests also verified the accuracy of the Computational Fluid Dynamic (CFD) modeling used to develop the RRI design and highlighted the importance of using CFD modeling to properly locate and configure the reagent injectors within the furnace. Low NOx firing conditions can adversely impact boiler operation due to increased waterwall wastage (corrosion) and increased soot production. A corrosion monitoring system that uses electrochemical noise (ECN) corrosion probes to monitor, on a real-time basis, high temperature corrosion events within the boiler was evaluated. Field tests were successfully conducted at two plants. The Ohio Coal Development Office provided financial assistance to perform the field tests. To investigate soot behavior, an advanced model to predict soot production and destruction was implemented into an existing reacting CFD modeling tool. Comparisons between experimental data collected

Slagging in a pulverised-coal-fired boiler

Energy Technology Data Exchange (ETDEWEB)

Devir, G.P.; Pohl, J.H.; Creelman, R.A. [University of Queensland, St. Lucia, Qld. (Australia). Dept. of Chemical Engineering

2000-07-01

This paper describes a technique to evaluate the severity of slagging of a coal in a pulverised-coal-fired boiler. There are few data in the literature on the nature of in-situ boiler slags, their rate of growth and/or their strength properties relevant to sootblowing. The latter is thought to be of more concern to boiler operators and gives rise to the significance of selecting suitable strength tests. As well as standardised methods for characterising pulverised coal performance in a boiler, several novel and less popular techniques are discussed in detail. A suite of three sub-bituminous coals from the Callide Coalfields, Biloela (600 km north of Brisbane), has been selected for slagging tests in the 350 MW{sub e} units of Callide 'B' power station. Disposable air-cooled mild steel slagging probes have been constructed to simulate the conditions for deposit formation in the boiler region. To date, tests for one of these coals has been completed and preliminary results are presented. Once testing for the remaining coals has been completed, it is anticipated that the differences exhibited in deposit growth and strength may be correlated with typical variations in physical and chemical properties of the pulverised coal.

Apparatus and method of controlling the thermal performance of an oxygen-fired boiler

Science.gov (United States)

Levasseur, Armand A.; Kang, Shin G.; Kenney, James R.; Edberg, Carl D.

2017-09-05

Disclosed herein is a method of controlling the operation of an oxy-fired boiler; the method comprising combusting a fuel in a boiler; producing a heat absorption pattern in the boiler; discharging flue gases from the boiler; recycling a portion of the flue gases to the boiler; combining a first oxidant stream with the recycled flue gases to form a combined stream; splitting the combined stream into several fractions; and introducing each fraction of the combined stream to the boiler at different points of entry to the boiler.

Ash transformation in suspension fired boilers co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

The properties of the ash from co-firing of coal and straw have a large influence on boiler operation, flue gas cleaning equipment and appropriate utilization of the fly ash. A study on the fuel composition and local conditions influence on fly ash properties has been done by making entrained flo...

Cofiring of biofuels in coal fired boilers: Results of case study analysis

Energy Technology Data Exchange (ETDEWEB)

Tillman, D.A. [Ebasco Environmental, Sacramento, CA (United States); Hughes, E. [Electric Power Research Institute, Palo Alto, CA (United States); Gold, B.A. [TVA, Chattanooga, TN (United States)

1993-12-31

Ebasco Environmental and Reaction Engineering, under contract to EPRI, performed a case study analysis of cofiring biomass in coal-fired boilers of the Tennessee Valley Authority (TVA). The study was also sponsored by DOE. This analysis included evaluating wood fuel receiving, preparation, and combustion in pulverized coal (PC) boilers and cyclone furnaces and an assessment of converting wood into pyrolysis oil or low Btu gas for use in a new combined cycle combustion turbine (CCCT) installation. Cofiring wood in existing coal-fired boilers has the most immediate potential for increasing the utilization of biofuels in electricity generation. Cofiring biofuels with coal can potentially generate significant benefits for utilities including: (1) reducing emissions of SO{sub 2} and NO{sub x}; (2) reducing the net emissions of CO{sub 2}; (3) potentially reducing the fuel cost to the utility depending upon local conditions and considering biomass is potentially exempt from the proposed Btu tax and may get a 1.5 cent/kWh credit for energy generated by wood combustion; (4) supporting local industrial forest industry; and (5) providing a long term market for the development of a biofuel supply and delivery industry. Potential benefits are reviewed in the context of cofiring biofuel at a rate of 15% heat input to the boiler, and compares this cofiring strategy and others previously tested or developed by other utilities. Other issues discussed include: (1) wood fuel specifications as a function of firing method; (2) wood fuel receiving and preparation system requirements; (3) combustion system requirements for cofiring biofuels with coal; (4) combustion impacts of firing biofuels with coal; (5) system engineering issues; (6) the economics of cofiring biofuel with coal. The Allen, TN 330 MW(e) cyclone boiler and Kingston, TN 135 MW(e) Boiler {number_sign}1, a tangentially fired PC unit, case studies are then summarized in the paper, highlighting the cofiring opportunities.

Advanced char burnout models for the simulation of pulverized coal fired boilers

Energy Technology Data Exchange (ETDEWEB)

T. Severin; S. Wirtz; V. Scherer [Ruhr-University, Bochum (Germany). Institute of Energy Plant Technology (LEAT)

2005-07-01

The numerical simulation of coal combustion processes is widely used as an efficient means to predict burner or system behaviour. In this paper an approach to improve CFD simulations of pulverized coal fired boilers with advanced coal combustion models is presented. In simple coal combustion models, first order Arrhenius rate equations are used for devolatilization and char burnout. The accuracy of such simple models is sufficient for the basic aspects of heat release. The prediction of carbon-in-ash is one aspect of special interest in the simulation of pulverized coal fired boilers. To determine the carbon-in-ash levels in the fly ash of coal fired furnaces, the char burnout model has to be more detailed. It was tested, in how far changing operating conditions affect the carbon-in-ash prediction of the simulation. To run several test cases in a short time, a simplified cellnet model was applied. To use a cellnet model for simulations of pulverized coal fired boilers, it was coupled with a Lagrangian particle model, used in CFD simulations, too. 18 refs., 5 figs., 5 tabs.

Indication of the incineration situation using image analysis of the grate boilers fireplace; Indikation av foerbraenningssituationen genom bildanalys av rostens eldstad

Energy Technology Data Exchange (ETDEWEB)

Persson, Anna; Helgesson, Johan [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

2004-12-01

Vattenfall Utveckling AB has earlier performed tests where the incineration situation in a black liquor recovery boiler (BLRB) has been investigated using a simple water-cooled camera. It was also shown possible to repress emission lines for e.g., sodium. These results led to wishes of performing the same tests in a grate boiler. Initially in the project, an investigation about what effect optical filters has on the image from a camera that captures the incineration situation in a grate boiler. The goal was to improve the conditions for flame front detection using image analysis, i.e., to increase the contrast between flames (the flame front) and no flames (bed, ashes, walls etc.). The result was that the image improvement optical filters were predicted to give, did not happen. The conclusion of the investigation is therefore that the best result is achieved when no information-reducing filters are used in front of the camera. However, for cameras using automatic shutter, intensity-reducing filters are recommended. After that, an image analysis algorithm to automatically detect the location of the flame front on the bed was implemented. The evaluation of the algorithm was successfully performed on movies from three grate boilers. This method should be possible to implement for all types of grate boilers, regardless of size and fuel type. However, the material (e.g., wide angle objective) and the placement of the camera have to be individually adjusted. In a future project, the goal is to be able to reconnect this information about the instant incineration situation to the control system to control e.g., the air supply or the fuel feed. This could lead to lower emissions, higher efficiency and an operation less sensitive against changes in fuel quality.

Demonstration of SCR technology for the control of NOx emissions from high-sulfur coal-fired utility boilers

Energy Technology Data Exchange (ETDEWEB)

Hinton, W.S. [W.S. Hinton and Associates, Cantonment, FL (United States); Maxwell, J.D.; Healy, E.C.; Hardman, R.R. [Southern Company Services, Inc., Birmingham, AL (United States); Baldwin, A.L. [Dept. of Energy, Pittsburgh, PA (United States)

1997-12-31

This paper describes the completed Innovative Clean Coal Technology project which demonstrated SCR technology for reduction of flue gas NO{sub x} emissions from a utility boiler burning US high-sulfur coal. The project was sponsored by the US Department of Energy, managed and co-funded by Southern Company Services, Inc. on behalf of the Southern Company, and also co-funded by the Electric Power Research Institute and Ontario Hydro. The project was located at Gulf Power Company`s Plant Crist Unit 5 (a 75 MW tangentially-fired boiler burning US coals that had a sulfur content ranging from 2.5--2.9%), near Pensacola, Florida. The test program was conducted for approximately two years to evaluate catalyst deactivation and other SCR operational effects. The SCR test facility had nine reactors: three 2.5 MW (5,000 scfm), and operated on low-dust flue gas. The reactors operated in parallel with commercially available SCR catalysts obtained from suppliers throughout the world. Long-term performance testing began in July 1993 and was completed in July 1995. A brief test facility description and the results of the project are presented in this paper.

A review: Fly ash and deposit formation in PF fired biomass boilers

DEFF Research Database (Denmark)

Jensen, Peter Arendt; Jappe Frandsen, Flemming; Wu, Hao

2016-01-01

In recent years suspension fired boilers have been increasingly used for biomass based heat and power production in several countries. This has included co-firing of coal and straw, up to 100% firing of wood or straw and the use of additives to remedy problems with biomass firing. In parallel...

Howden-Microcoal system for the conversion of industrial oil or gas fired boilers

Energy Technology Data Exchange (ETDEWEB)

Cooper, J

1985-01-01

The technical and economic aspects of the conversion of an industrial boiler designed for oil firing at Courtaulds plc Greenfield site in North Wales to Howden-Microcoal firing are discussed. The production of Howden-Micro coal (an ultrafine or 'micronised' coal) is described and the Howden-Microcoal processor is compared with other fluid energy and mechanical mills. A typical boiler installation and modifications required for conversion to Howden-Microcoal firing are presented along with the main results of the Courtauld's tests. Cost, conversion time and the effect on average steam generation costs are considered.

Successful experience with limestone and other sorbents for combustion of biomass in fluid bed power boilers

Energy Technology Data Exchange (ETDEWEB)

Coe, D.R. [LG& E Power Systems, Inc., Irvine, CA (United States)

1993-12-31

This paper presents the theoretical and practical advantages of utilizing limestone and other sorbents during the combustion of various biomass fuels for the reduction of corrosion and erosion of boiler fireside tubing and refractory. Successful experiences using a small amount of limestone, dolomite, kaolin, or custom blends of aluminum and magnesium compounds in fluid bed boilers fired with biomass fuels will be discussed. Electric power boiler firing experience includes bubbling bed boilers as well as circulating fluid bed boilers in commercial service on biomass fuels. Forest sources of biomass fuels fired include wood chips, brush chips, sawmill waste wood, bark, and hog fuel. Agricultural sources of biomass fuels fired include grape vine prunings, bean straw, almond tree chips, walnut tree chips, and a variety of other agricultural waste fuels. Additionally, some urban sources of wood fuels have been commercially burned with the addition of limestone. Data presented includes qualitative and quantitative analyses of fuel, sorbent, and ash.

Improving global fire carbon emissions estimates by combining moderate resolution burned area and active fire observations

Science.gov (United States)

Randerson, J. T.; Chen, Y.; Giglio, L.; Rogers, B. M.; van der Werf, G.

2011-12-01

In several important biomes, including croplands and tropical forests, many small fires exist that have sizes that are well below the detection limit for the current generation of burned area products derived from moderate resolution spectroradiometers. These fires likely have important effects on greenhouse gas and aerosol emissions and regional air quality. Here we developed an approach for combining 1km thermal anomalies (active fires; MOD14A2) and 500m burned area observations (MCD64A1) to estimate the prevalence of these fires and their likely contribution to burned area and carbon emissions. We first estimated active fires within and outside of 500m burn scars in 0.5 degree grid cells during 2001-2010 for which MCD64A1 burned area observations were available. For these two sets of active fires we then examined mean fire radiative power (FRP) and changes in enhanced vegetation index (EVI) derived from 16-day intervals immediately before and after each active fire observation. To estimate the burned area associated with sub-500m fires, we first applied burned area to active fire ratios derived solely from within burned area perimeters to active fires outside of burn perimeters. In a second step, we further modified our sub-500m burned area estimates using EVI changes from active fires outside and within of burned areas (after subtracting EVI changes derived from control regions). We found that in northern and southern Africa savanna regions and in Central and South America dry forest regions, the number of active fires outside of MCD64A1 burned areas increased considerably towards the end of the fire season. EVI changes for active fires outside of burn perimeters were, on average, considerably smaller than EVI changes associated with active fires inside burn scars, providing evidence for burn scars that were substantially smaller than the 25 ha area of a single 500m pixel. FRP estimates also were lower for active fires outside of burn perimeters. In our

Experimental investigation and mathematical modelling of wood combustion in a moving grate boiler

International Nuclear Information System (INIS)

Zhang, Xiaohui; Chen, Qun; Sharifi, Vida; Swithenbank, Jim; Bradford, Richard

2010-01-01

The use of biomass to generate energy offers significant environmental advantages for the reduction in emissions of greenhouse gases. The main objective of this study was to investigate the performance of a small scale biomass heating plant: i.e. combustion characteristics and emissions. An extensive series of experimental tests was carried out at a small scale residential biomass heating plant i.e. wood chip fired boiler. The concentrations of CO, NO x , particulate matter in the flue gas were measured. In addition, mathematical modelling work using FLIC and FLUENT codes was carried out in order to simulate the overall performance of the wood fired heating system. Results showed that pollutant emissions from the boiler were within the relative emission limits. Mass concentration of CO emission was 550-1600 mg/m 3 (10% O 2 ). NO x concentration in the flue gas from the wood chips combustion varied slightly between 28 and 60 ppmv. Mass concentration of PM 10 in the flue gas was 205 mg/m 3 (10% O 2 ) The modelling results showed that most of the fuel was burnt inside the furnace and little CO was released from the system due to the high flue gas temperature in the furnace. The injection of the secondary air provided adequate mixing and favourable combustion conditions in the over-bed chamber in the wood chips fired boiler. This study has shown that the use of wood heating system result in much lower CO 2 emissions than from a fossil fuel e.g. coal fired heating system. (author)

Hazardous emissions, operating practices, and air regulations at industrial wood-fired facilities in Wisconsin

International Nuclear Information System (INIS)

Hubbard, A.J.

1993-01-01

Since October of 1988 the State of Wisconsin Department of Natural Resources has regulated over four hundred substances as hazardous air pollutants. The rule regulates new as well as existing sources of air pollution in Wisconsin. Consequently, all permits to operate an air pollution source in Wisconsin must address the hazardous air emissions potential of the source. While widely perceived as a clean-burning fuel, wood is often burned in a manner which clearly results in significant emissions of very hazardous air pollutants. Research conducted on a 20 million BTU per hour wood-fired spreader stoker boiler in northern Wisconsin showed that this boiler has the potential to emit 0.022 pound of benzene and 0.012 pound of formaldehyde per ton (lb/ton) of wood fired. Recent stack tests at more than a dozen other small industrial wood-fired facilities in Wisconsin show a range of formaldehyde emissions of 0.0007--0.1950 lb/ton. Work at Birchwood Lumber ampersand Veneer showed that the benzene and formaldehyde emission rates under good firing conditions are an order of magnitude lower than the benzene and formaldehyde emission rates under poor firing conditions. This finding has supported Wisconsin's regulatory approach of encouraging wood-fired facilities to enhance the quality of the combustion process as a technique to minimize the hazardous air pollution potential of industrial wood combustion. The Wisconsin strategy is to define open-quotes good combustion technologyclose quotes through easily measurable combustion parameters rather than emission standards. This paper presents several techniques in use in Wisconsin to comply with open-quotes good combustion technologyclose quotes for industrial wood-fired furnaces. These techniques include fuel blending overfire air, furnace insulation, and proper grate design

Wood-Fired Boiler System Evaluation at Fort Stewart, GA

National Research Council Canada - National Science Library

Potts, Noel

2002-01-01

Part of the plan to modernize the central energy plant (CEP) at Fort Stewart, GA is focused on the installations wood-fired boiler, which provides steam for heating, cooling, and domestic hot water. The U.S...

40 CFR Appendix A to Part 76 - Phase I Affected Coal-Fired Utility Units With Group 1 or Cell Burner Boilers

Science.gov (United States)

2010-07-01

... Units With Group 1 or Cell Burner Boilers A Appendix A to Part 76 Protection of Environment... 1 or Cell Burner Boilers Table 1—Phase I Tangentially Fired Units State Plant Unit Operator ALABAMA... Vertically fired boiler. 2 Arch-fired boiler. Table 3—Phase I Cell Burner Technology Units State Plant Unit...

Burn Severities, Fire Intensities, and Impacts to Major Vegation Types from the Cerro Grande Fire

International Nuclear Information System (INIS)

Balice, R.G.; Bennett, K.D.; Wright, M.A.

2005-01-01

The Cerro Grande Fire resulted in major impacts and changes to the ecosystems that were burned. To partially document these effects, we estimated the acreage of major vegetation types that were burned at selected burn severity levels and fire intensity levels. To accomplish this, we adopted independently developed burn severity and fire intensity maps, in combination with a land cover map developed for habitat management purposes, as a basis for the analysis. To provide a measure of confidence in the acreage estimates, the accuracies of these maps were also assessed. In addition, two other maps of comparable quality were assessed for accuracy: one that was developed for mapping fuel risk and a second map that resulted from a preliminary application of an evolutionary computation software system, called GENIE. According to the burn severity map and the fire intensity map, the Cerro Grande Fire is estimated to have covered 42,885.4 acres and 42,854.7 acres, respectively. Of this, 57.0 percent was burned at low severity and 34.7 percent was burned at high severity. Similarly, 40.0 percent of the Cerro Grande Fire burned at high fire intensity, greater than 70 percent mortality, while 33.1 percent burned at moderately low intensity, 10 to 40 percent mortality. The most frequently burned cover types over the entire Cerro Grande Fire were ponderosa pine forest and mixed conifer forest, at approximately 43 percent each. However, portions of the fire that burned on Los Alamos National Laboratory (LANL) property were predominantly in ponderosa pine forests, whereas the Cerro Grande Fire burned primarily in mixed conifer forests on lands managed by other agencies. Some of the polygons of burn severities and fire intensities were extensive. The two largest burn severity polygons were 10,111 acres and 10,903 acres and these were burned at low severity. The next two largest polygons were 8999 acres (14 square miles) and 1551 acres (2.4 square miles) and both of these polygons

Firing a sub-bituminous coal in pulverized coal boilers configured for bituminous coals

Energy Technology Data Exchange (ETDEWEB)

N. Spitz; R. Saveliev; M. Perelman; E. Korytni; B. Chudnovsky; A. Talanker; E. Bar-Ziv [Ben-Gurion University of the Negev, Beer-Sheva (Israel)

2008-07-15

It is important to adapt utility boilers to sub-bituminous coals to take advantage of their environmental benefits while limiting operation risks. We discuss the performance impact that Adaro, an Indonesian sub-bituminous coal with high moisture content, has on opposite-wall and tangentially-fired utility boilers which were designed for bituminous coals. Numerical simulations were made with GLACIER, a computational-fluid-dynamic code, to depict combustion behavior. The predictions were verified with full-scale test results. For analysis of the operational parameters for firing Adaro coal in both boilers, we used EXPERT system, an on-line supervision system developed by Israel Electric Corporation. It was concluded that firing Adaro coal, compared to a typical bituminous coal, lowers NOx and SO{sub 2} emissions, lowers LOI content and improves fouling behavior but can cause load limitation which impacts flexible operation. 21 refs., 7 figs., 3 tabs.

Influence of the overfire air ratio on the NO(x) emission and combustion characteristics of a down-fired 300-MW(e) utility boiler.

Science.gov (United States)

Ren, Feng; Li, Zhengqi; Chen, Zhichao; Fan, Subo; Liu, Guangkui

2010-08-15

Down-fired boilers used to burn low-volatile coals have high NO(x) emissions. To find a way of solving this problem, an overfire air (OFA) system was introduced on a 300 MW(e) down-fired boiler. Full-scale experiments were performed on this retrofitted boiler to explore the influence of the OFA ratio (the mass flux ratio of OFA to the total combustion air) on the combustion and NO(x) emission characteristics in the furnace. Measurements were taken of gas temperature distributions along the primary air and coal mixture flows, average gas temperatures along the furnace height, concentrations of gases such as O(2), CO, and NO(x) in the near-wall region and carbon content in the fly ash. Data were compared for five different OFA ratios. The results show that as the OFA ratio increases from 12% to 35%, the NO(x) emission decreases from 1308 to 966 mg/Nm(3) (at 6% O(2) dry) and the carbon content in the fly ash increases from 6.53% to 15.86%. Considering both the environmental and economic effect, 25% was chosen as the optimized OFA ratio.

Integrating multi-objective optimization with computational fluid dynamics to optimize boiler combustion process of a coal fired power plant

International Nuclear Information System (INIS)

Liu, Xingrang; Bansal, R.C.

2014-01-01

Highlights: • A coal fired power plant boiler combustion process model based on real data. • We propose multi-objective optimization with CFD to optimize boiler combustion. • The proposed method uses software CORBA C++ and ANSYS Fluent 14.5 with AI. • It optimizes heat flux transfers and maintains temperature to avoid ash melt. - Abstract: The dominant role of electricity generation and environment consideration have placed strong requirements on coal fired power plants, requiring them to improve boiler combustion efficiency and decrease carbon emission. Although neural network based optimization strategies are often applied to improve the coal fired power plant boiler efficiency, they are limited by some combustion related problems such as slagging. Slagging can seriously influence heat transfer rate and decrease the boiler efficiency. In addition, it is difficult to measure slag build-up. The lack of measurement for slagging can restrict conventional neural network based coal fired boiler optimization, because no data can be used to train the neural network. This paper proposes a novel method of integrating non-dominated sorting genetic algorithm (NSGA II) based multi-objective optimization with computational fluid dynamics (CFD) to decrease or even avoid slagging inside a coal fired boiler furnace and improve boiler combustion efficiency. Compared with conventional neural network based boiler optimization methods, the method developed in the work can control and optimize the fields of flue gas properties such as temperature field inside a boiler by adjusting the temperature and velocity of primary and secondary air in coal fired power plant boiler control systems. The temperature in the vicinity of water wall tubes of a boiler can be maintained within the ash melting temperature limit. The incoming ash particles cannot melt and bond to surface of heat transfer equipment of a boiler. So the trend of slagging inside furnace is controlled. Furthermore, the

Influence of Deposit Formation on Corrosion at a Straw Fired boiler

DEFF Research Database (Denmark)

Hansen, Lone Aslaug; Michelsen, Hanne Philbert; Frandsen, Flemming

2000-01-01

Straw-fired boilers generally experience severe problems with deposit formation and are expected to suffer from severe superheater corrosion at high steam temperatures due to the large alkali and chlorine content in straw. In this study, deposits collected (1) on air-cooled probes and (2) directly...... at the existing heat transfer surfaces of a straw-fired boiler have been examined. Deposits collected on air-cooled probes were found to consist of an inner layer of KCl and an outer layer of sintered fly ash. Ash deposits formed on the heat transfer surfaces all had a characteristic layered structure......, with a dense layer of K2SO4 present adjacent to the metal surface. It is argued that the K2SO4 layer present adjacent to the metal surface may lead to reduced corrosion rates at this boiler. A discussion of the deposit structure, the K2SO4 layer formation mechanism, and the influence of the inner layer...

GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS: PHASE II--PILOT SCALE TESTING AND UPDATED PERFORMANCE AND ECONOMICS FOR OXYGEN FIRED CFB WITH CO2 CAPTURE

Energy Technology Data Exchange (ETDEWEB)

Nsakala ya Nsakala; Gregory N. Liljedahl; David G. Turek

2004-10-27

Because fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this Phase II study, ALSTOM Power Inc. (ALSTOM) has investigated one promising near-term coal fired power plant configuration designed to capture CO{sub 2} from effluent gas streams for sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}, along with some moisture, nitrogen, oxygen, and trace gases like SO{sub 2} and NO{sub x}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB plants results in significant Boiler Island cost savings resulting from reduced component The overall objective of the Phase II workscope, which is the subject of this report, is to generate a refined technical and economic evaluation of the Oxygen fired CFB case (Case-2 from Phase I) utilizing the information learned from pilot-scale testing of this concept. The objective of the pilot-scale testing was to generate detailed technical data needed to establish advanced CFB design requirements and performance when firing coals and

SOURCE SAMPLING FINE PARTICULATE MATTER: WOOD-FIRED INDUSTRIAL BOILER

Science.gov (United States)

The report provides a profile for a wood-fired industrial boiler equipped with a multistage electrostatic precipitator control device. Along with the profile of emissions of fine particulate matter of aerodynamic diameter of 2.5 micrometers or less (PM-2.5), data are also provide...

SEM Investigation of Superheater Deposits from Biomass-Fired Boilers

DEFF Research Database (Denmark)

Jensen, Peter Arendt; Frandsen, Flemming; Hansen, Jørn

2004-01-01

, mature superheater deposit samples were extracted from two straw-fired boilers, Masnedø and Ensted, with fuel inputs of 33 MWth and 100 MWth, respectively. SEM (scanning electron microscopy) images and EDX (energy dispersive X-ray) analyses were performed on the deposit samples. Different strategies...

Temporal trends and spatial variation characteristics of primary air pollutants emissions from coal-fired industrial boilers in Beijing, China

International Nuclear Information System (INIS)

Xue, Yifeng; Tian, Hezhong; Yan, Jing; Zhou, Zhen; Wang, Junling; Nie, Lei; Pan, Tao; Zhou, Junrui; Hua, Shenbing; Wang, Yong; Wu, Xiaoqing

2016-01-01

Coal-fired combustion is recognized as a significant anthropogenic source of atmospheric compounds in Beijing, causing heavy air pollution events and associated deterioration in visibility. Obtaining an accurate understanding of the temporal trends and spatial variation characteristics of emissions from coal-fired industrial combustion is essential for predicting air quality changes and evaluating the effectiveness of current control measures. In this study, an integrated emission inventory of primary air pollutants emitted from coal-fired industrial boilers in Beijing is developed for the period of 2007–2013 using a technology-based approach. Future emission trends are projected through 2030 based on current energy-related and emission control policies. Our analysis shows that there is a general downward trend in primary air pollutants emissions because of the implementation of stricter local emission standards and the promotion by the Beijing municipal government of converting from coal-fired industrial boilers to gas-fired boilers. However, the ratio of coal consumed by industrial boilers to total coal consumption has been increasing, raising concerns about the further improvement of air quality in Beijing. Our estimates indicate that the total emissions of PM 10 , PM 2.5 , SO 2 , NO x , CO and VOCs from coal-fired industrial boilers in Beijing in 2013 are approximately 19,242 t, 13,345 t, 26,615 t, 22,965 t, 63,779 t and 1406 t, respectively. Under the current environmental policies and relevant energy savings and emission control plans, it may be possible to reduce NO x and other air pollutant emissions by 94% and 90% by 2030, respectively, if advanced flue gas purification technologies are implemented and coal is replaced with natural gas in the majority of existing boilers. - Highlights: • A unit-based emission inventory of coal-fired industrial boilers is developed. • Temporal trend of historical period 2007–2013 and the future till 2030 is

Studies of the fate of sulfur trioxide in coal-fired utility boilers based on modified selected condensation methods.

Science.gov (United States)

Cao, Yan; Zhou, Hongcang; Jiang, Wu; Chen, Chien-Wei; Pan, Wei-Ping

2010-05-01

The formation of sulfur trioxide (SO(3)) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM(2.5). Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(3) during SO(3) sampling. A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO(3), was applied in SO(3) tests in three full-scale utility boilers. For the two units burning bituminous coal, SO(3) levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO(2) to SO(3,) and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO(3) estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO(3) removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO(3) across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO(3).

[Emission Characteristics of Water-Soluble Ions in Fumes of Coal Fired Boilers in Beijing].

Science.gov (United States)

Hu, Yue-qi; Ma, Zhao-hui; Feng, Ya-jun; Wang, Chen; Chen, Yuan-yuan; He, Ming

2015-06-01

Selecting coal fired boilers with typical flue gas desulfurization and dust extraction systems in Beijing as the study objects, the issues and characteristics of the water-soluble ions in fumes of coal fired boilers and theirs influence factors were analyzed and evaluated. The maximum mass concentration of total water-soluble ions in fumes of coal fired boilers in Beijing was 51.240 mg x m(-3) in the benchmark fume oxygen content, the minimum was 7.186 mg x m(-3), and the issues of the water-soluble ions were uncorrelated with the fume moisture content. SO4(2-) was the primary characteristic water-soluble ion for desulfurization reaction, and the rate of contribution of SO4(2-) in total water-soluble ions ranged from 63.8% to 81.0%. F- was another characteristic water-soluble ion in fumes of thermal power plant, and the rate of contribution of F- in total water-soluble ions ranged from 22.2% to 32.5%. The fume purification technologies significantly influenced the issues and the emission characteristics of water-soluble ions in fumes of coal fired boilers. Na+ was a characteristic water-soluble ion for the desulfurizer NaOH, NH4+ and NO3+ were characteristic for the desulfurizer NH4HCO3, and Mg2+ was characteristic for the desulfurizer MgO, but the Ca2+ emission was not increased by addition of the desulfurizer CaO or CaCO3 The concentrations of NH4+ and NO3- in fumes of thermal power plant were lower than those in fumes of industrial or heating coal fired boilers. The form of water-soluble ions was significantly correlated with fume temperature. The most water-soluble ions were in superfine state at higher fume temperature and were not easily captured by the filter membrane.

Fiber Bragg Grating Array as a Quasi Distributed Temperature Sensor for Furnace Boiler Applications

Science.gov (United States)

Reddy, P. Saidi; Prasad, R. L. N. Sai; Sengupta, D.; Shankar, M. Sai; Srimannarayana, K.; Kishore, P.; Rao, P. Vengal

2011-10-01

This paper presents the experimental work on distributed temperature sensing making use of Fiber Bragg grating (FBG) array sensor for possible applications in the monitoring of temperature profile in high temperature boilers. A special sensor has been designed for this purpose which consists of four FBGs (of wavelengths λB1 = 1547.28 nm, λB2 = 1555.72 nm, λB3 = 1550.84 nm, λB4 = 1545.92 nm) written in hydrogen loaded fiber in line with a spacing of 15 cm between them. All the FBGs are encapsulated inside a stainless steel tube for avoiding micro cracks using rigid probe technique. The spatial distribution of temperature profile inside a prototype boiler has been measured experimentally both in horizontal and vertical directions employing the above sensor and the results are presented.

Optimalisasi Of Efficiency Terms And Test The Value Kalor Of Perfomansi Boiler Use The Energi Biomassa Upon Which Burn Alternative

Directory of Open Access Journals (Sweden)

Imam Kholiq

2015-08-01

Full Text Available ABSTRACTION Especial Fuel used by Boiler PG MODJO PANGGUNG TULUNGAGUNG PTPN X is bagasse and oil burn the residu MFO. A lot of PG in Indonesia which exactly use the very costly fossil fuel so that generate the inefisiensi. Research by enhancing fiber cangkang fiber chaff to efficiency termis perfomansi and performance of boiler PG MODJO PODIUM. Assess the kalor of every-every fuel calculated given the composition of every fuel by using existing equation from literature calculation consume the fuel space volume burn the efficiency from every fuel to boiler and expense efficiency from every fuel used. From calculation of every fuel is hence got by result that Fuel efficiency use the smaller dregs fuel compared to from fuel of fiber and oil burn the residu MFO. LaterThen from facetof material cost burn the bagasse more efficient from at fuel of fiber and oil burn the residu MFO. To reply the the problem hence researcher use the indirect method. This method own the advantage that is can know the balance of complete and energi substance to eachevery stream which can facilitate in identifying opdon to increase is optimal of efficiency of termis boiler.

Chemical and physical properties of cyclone fly ash from the grate-fired boiler incinerating forest residues at a small municipal district heating plant (6MW).

Science.gov (United States)

Pöykiö, R; Rönkkömäki, H; Nurmesniemi, H; Perämäki, P; Popov, K; Välimäki, I; Tuomi, T

2009-03-15

In Finland, the new limit values for maximal allowable heavy metal concentrations for materials used as an earth construction agent came into force in July 2006. These limit values are applied if ash is utilized, e.g. in roads, cycling paths, pavements, car parks, sport fields, etc. In this study we have determined the most important chemical and physical properties of the cyclone fly ash originating from the grate-fired boiler incinerating forest residues (i.e. wood chips, sawdust and bark) at a small municipal district heating plant (6 MW), Northern Finland. This study clearly shows that elements are enriched in cyclone fly ash, since the total element concentrations in the cyclone fly ash were within 0.2-10 times higher than those in the bottom ash. The total concentrations of Cd (25 mg kg(-1); d.w.), Zn (3630 mg kg(-1); d.w.), Ba (4260 mg kg(-1); d.w.) and Hg (1.7 mg kg(-1); d.w.) exceeded the limit values, and therefore the cyclone fly ash cannot be used as an earth construction agent. According to the leached amounts of Cr (38 mg kg(-1); d.w.), Zn (51 mg kg(-1); d.w.) and sulphate (50,000 mg kg(-1); d.w.), the cyclone fly ash is classified as a hazardous waste, and it has to be deposited in a hazardous waste landfill.

Application of the decree 2910 for coal fired boilers; Application de l`arrete 2910 aux chaudieres a charbon

Energy Technology Data Exchange (ETDEWEB)

Hing, K. [CDF Energie, Charbonnages de France, 92 - Rueil-Malmaison (France)

1997-12-31

The impacts of the new French decree 2910 concerning the classification of all combustion equipment with regards to their energy sources, energy efficiency and pollution control, on 2 to 20 MW coal-fired boilers, are discussed, with emphasis on their pollutant emissions (SO{sub 2}, NO{sub x} and ashes). The compositions of several coals is presented and the various types of coal-fired boilers adapted to the new decree are presented: automatic boilers, dense fluidized bed boilers, vibrating and chain grids with fume tubes and water tubes

NOX EMISSION CONTROL OPTIONS FOR COAL-FIRED ELECTRIC UTILITY BOILERS

Science.gov (United States)

The paper reviews NOx control options for coal-fired electric utility boilers. (NOTE: Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, revision of the New Source Performance Standards (NSPS) for NOx emissions from utility sources, and Ozone Transpor...

Assessing the Exergy Costs of a 332-MW Pulverized Coal-Fired Boiler

Directory of Open Access Journals (Sweden)

Victor H. Rangel-Hernandez

2016-08-01

Full Text Available In this paper, we analyze the exergy costs of a real large industrial boiler with the aim of improving efficiency. Specifically, the 350-MW front-fired, natural circulation, single reheat and balanced draft coal-fired boiler forms part of a 1050-MW conventional power plant located in Spain. We start with a diagram of the power plant, followed by a formulation of the exergy cost allocation problem to determine the exergy cost of the product of the boiler as a whole and the expenses of the individual components and energy streams. We also define a productive structure of the system. Furthermore, a proposal for including the exergy of radiation is provided in this study. Our results show that the unit exergy cost of the product of the boiler goes from 2.352 to 2.5, and that the maximum values are located in the ancillary electrical devices, such as induced-draft fans and coil heaters. Finally, radiation does not have an effect on the electricity cost, but affects at least 30% of the unit exergy cost of the boiler’s product.

Steam generation: fossil-fired systems: utility boilers; industrial boilers; boiler auxillaries; nuclear systems: boiling water; pressurized water; in-core fuel management; steam-cycle systems: condensate/feedwater; circulating water; water treatment

International Nuclear Information System (INIS)

Anon.

1982-01-01

A survey of development in steam generation is presented. First, fossil-fired systems are described. Progress in the design of utility and industrial boilers as well as in boiler auxiliaries is traced. Improvements in coal pulverizers, burners that cut pollution and improve efficiency, fans, air heaters and economisers are noted. Nuclear systems are then described, including the BWR and PWR reactors, in-core fuel management techniques are described. Finally, steam-cycle systems for fossil-fired and nuclear power plants are reviewed. Condensate/feedwater systems, circulating water systems, cooling towers, and water treatment systems are discussed

Identifying individual fires from satellite-derived burned area data

CSIR Research Space (South Africa)

Archibald, S

2009-07-01

Full Text Available An algorithm for identifying individual fires from the Modis burned area data product is introduced for southern Africa. This algorithm gives the date of burning, size of fire, and location of the centroid for all fires identified over 8 years...

Risk of hospitalization for fire-related burns during extreme cold weather.

Science.gov (United States)

Ayoub, Aimina; Kosatsky, Tom; Smargiassi, Audrey; Bilodeau-Bertrand, Marianne; Auger, Nathalie

2017-10-01

Environmental factors are important predictors of fires, but no study has examined the association between outdoor temperature and fire-related burn injuries. We sought to investigate the relationship between extremely cold outdoor temperatures and the risk of hospitalization for fire-related burns. We carried out a time-stratified case-crossover study of 2470 patients hospitalized for fire-related burn injuries during cold months between 1989 and 2014 in Quebec, Canada. The main exposure was the minimum outdoor temperature on the day of and the day before the burn. We computed odds ratios (OR) and 95% confidence intervals (CI) to evaluate the relationship between minimum temperature and fire-related burns, and assessed how associations varied across sex and age. Exposure to extreme cold temperature was associated with a significantly higher risk of hospitalization for fire-related burns. Compared with 0°C, exposure to a minimum temperature of -30°C was associated with an OR of 1.51 (95% CI 1.22-1.87) for hospitalization for fire-related burns. The associations were somewhat stronger for women, youth, and the elderly. Compared with 0°C, a minimum temperature of -30°C was associated with an OR for fire-related burn hospitalization of 1.65 for women (95% CI 1.13-2.40), 1.60 for age fire-related burns. Measures to prevent fires should be implemented prior to the winter season, and enhanced during extreme cold. Copyright © 2017 Elsevier Inc. All rights reserved.

Modelling of limestone injection for SO2 capture in a coal fired utility boiler

International Nuclear Information System (INIS)

Kovacik, G.J.; Reid, K.; McDonald, M.M.; Knill, K.

1997-01-01

A computer model was developed for simulating furnace sorbent injection for SO 2 capture in a full scale utility boiler using TASCFlow TM computational fluid dynamics (CFD) software. The model makes use of a computational grid of the superheater section of a tangentially fired utility boiler. The computer simulations are three dimensional so that the temperature and residence time distribution in the boiler could be realistically represented. Results of calculations of simulated sulphur capture performance of limestone injection in a typical utility boiler operation were presented

Ash fouling monitoring and key variables analysis for coal fired power plant boiler

Directory of Open Access Journals (Sweden)

Shi Yuanhao

2015-01-01

Full Text Available Ash deposition on heat transfer surfaces is still a significant problem in coal-fired power plant utility boilers. The effective ways to deal with this problem are accurate on-line monitoring of ash fouling and soot-blowing. In this paper, an online ash fouling monitoring model based on dynamic mass and energy balance method is developed and key variables analysis technique is introduced to study the internal behavior of soot-blowing system. In this process, artificial neural networks (ANN are used to optimize the boiler soot-blowing model and mean impact values method is utilized to determine a set of key variables. The validity of the models has been illustrated in a real case-study boiler, a 300MW Chinese power station. The results on same real plant data show that both models have good prediction accuracy, while the ANN model II has less input parameters. This work will be the basis of a future development in order to control and optimize the soot-blowing of the coal-fired power plant utility boilers.

A Pulverized Coal-Fired Boiler Optimized for Oxyfuel Combustion Technology

Directory of Open Access Journals (Sweden)

Tomáš Dlouhý

2012-01-01

Full Text Available This paper presents the results of a study on modifying a pulverized coal-fired steam boiler in a 250 MWe power plant for oxygen combustion conditions. The entry point of the study is a boiler that was designed for standard air combustion. It has been proven that simply substituting air by oxygen as an oxidizer is not sufficient for maintaining a satisfactory operating mode, not even with flue gas recycling. Boiler design optimization aggregating modifications to the boiler’s dimensions, heating surfaces and recycled flue gas flow rate, and specification of a flue gas recycling extraction point is therefore necessary in order to achieve suitable conditions for oxygen combustion. Attention is given to reducing boiler leakage, to which external pre-combustion coal drying makes a major contribution. The optimization is carried out with regard to an overall power plant conception for which a decrease in efficiency due to CO2 separation is formulated.

Combustion and NOx emission characteristics of a retrofitted down-fired 660 MWe utility boiler at different loads

Energy Technology Data Exchange (ETDEWEB)

Li, Z.Q.; Liu, G.K.; Zhu, Q.Y.; Chen, Z.C.; Ren, F. [Harbin Institute of Technology, Harbin (China)

2011-07-15

Industrial experiments were performed for a retrofitted 660 MWe full-scale down-fired boiler. Measurements of ignition of the primary air/fuel mixture flow, the gas temperature distribution of the furnace and the gas components in the furnace were conducted at loads of 660, 550 and 330 MWe. With decreasing load, the gas temperature decreases and the ignition position of the primary coal/air flow becomes farther along the axis of the fuel-rich pipe in the burner region under the arches. The furnace temperature also decreases with decreasing load, as does the difference between the temperatures in the burning region and the lower position of the burnout region. With decreasing load, the exhaust gas temperature decreases from 129.8{sup o}C to 114.3{sup o}C, while NOx emissions decrease from 2448 to 1610 mg/m{sup 3}. All three loads result in low carbon content in fly ash and great boiler thermal efficiency higher than 92%. Compared with the case of 660 MWe before retrofit, the exhaust gas temperature decreased from 136 to 129.8{sup o}C, the carbon content in the fly ash decreased from 9.55% to 2.43% and the boiler efficiency increased from 84.54% to 93.66%.

Does fire severity influence shrub resprouting after spring prescribed burning?

Science.gov (United States)

Fernández, Cristina; Vega, José A.; Fonturbel, Teresa

2013-04-01

Prescribed burning is commonly used to reduce the risk of severe wildfire. However, further information about the associated environmental effects is required to help forest managers select the most appropriate treatment. To address this question, we evaluated if fire severity during spring prescribed burning significantly affects the resprouting ability of two common shrub species in shrubland under a Mediterranean climate in NW Spain. Fire behaviour and temperatures were recorded in tagged individuals of Erica australis and Pterospartum tridentatum during prescribed burning. The number and length of resprouted shoots were measured three times (6, 12 and 18 months) after the prescribed burning. The influence of a series of fire severity indicators on some plant resprouting vigour parameters was tested by canonical correlation analysis. Six months and one year after prescribed burning, soil burn severity (measured by the absolute reduction in depth of the organic soil layer, maximum temperatures in the organic soil layer and the mineral soil surface during burning and the post-fire depth of the organic soil layer) reduced the resprouting vigour of E. australis and P. tridentatum. In contrast, direct measurements of fire effects on plants (minimum branch diameter, duration of temperatures above 300 °C in the shrub crown and fireline intensity) did not affect the post-fire plant vigour. Soil burn severity during spring prescribed burning significantly affected the short-term resprouting vigour in a mixed heathland in Galicia. The lack of effects eighteen months after prescribed burning indicates the high resilience of these species and illustrates the need to conciliate fire prevention and conservation goals.

NO{sub x} controls for coal-fired utility boilers in East Central Europe

Energy Technology Data Exchange (ETDEWEB)

Eskinazi, D. [Electric Power Research Inst., Washington, DC (United States); Tavoulareas, E.S. [Energy Technologies Enterprises Corp., McLean, VA (United States)

1995-12-01

Increasing environmental pressures worldwide, including East Central Europe are placing greater emphasis on NO{sub x} emission controls in utility power plants. Western Europe, Japan and the U.S. have significant experience in applying NO{sub x} controls, especially in boilers firing hard coal. Some countries in Europe (i.e., Germany and Austria), have gained experience in applying NO{sub x} controls in boilers firing low-rank coal. This experience can be applied to East Central European countries in providing the basis for planning NO{sub x} control projects, suggesting cost-effective solutions, and providing lessons learned. However, while the experience is generally applicable to East Central European countries, differences in boiler design, operation and coal characteristics also need to be considered. This paper begins with a comparison of the NO{sub x} regulations, identifies the key NO{sub x} control technologies and the worldwide experience with them, and discusses the achievable NO{sub x} reduction, O&M impacts, and retrofit costs for each technology. Emphasis is placed on retrofit applications for existing boilers, because new coal-fired power plants are not expected to be built for the next 5-10 years. This paper also focuses on technologies with relatively low cost and operational simplicity: combustion system tuning/optimization. low-NO{sub x} burners (LNB), overfire air (OFA), selective non-catalytic reduction (SNCR), and reburning.

Deciding Where to Burn: Stakeholder Priorities for Prescribed Burning of a Fire-Dependent Ecosystem

Directory of Open Access Journals (Sweden)

Jennifer K. Costanza

2011-03-01

Full Text Available Multiagency partnerships increasingly work cooperatively to plan and implement fire management. The stakeholders that comprise such partnerships differ in their perceptions of the benefits and risks of fire use or nonuse. These differences inform how different stakeholders prioritize sites for burning, constrain prescribed burning, and how they rationalize these priorities and constraints. Using a survey of individuals involved in the planning and implementation of prescribed fire in the Onslow Bight region of North Carolina, we examined how the constraints and priorities for burning in the longleaf pine (Pinus palustris ecosystem differed among three stakeholder groups: prescribed burn practitioners from agencies, practitioners from private companies, and nonpractitioners. Stakeholder groups did not differ in their perceptions of constraints to burning, and development near potentially burned sites was the most important constraint identified. The top criteria used by stakeholders to decide where to burn were the time since a site was last burned, and a site's ecosystem health, with preference given to recently burned sites in good health. Differences among stakeholder groups almost always pertained to perceptions of the nonecological impacts of burning. Prescribed burning priorities of the two groups of practitioners, and particularly practitioners from private companies, tended to be most influenced by nonecological impacts, especially through deprioritization of sites that have not been burned recently or are in the wildland-urban interface (WUI. Our results highlight the difficulty of burning these sites, despite widespread laws in the southeast U.S. that limit liability of prescribed burn practitioners. To avoid ecosystem degradation on sites that are challenging to burn, particularly those in the WUI, conservation partnerships can facilitate demonstration projects involving public and private burn practitioners on those sites. In summary

Thermal Effects by Firing Oil Shale Fuel in CFB Boilers

Science.gov (United States)

Neshumayev, D.; Ots, A.; Parve, T.; Pihu, T.; Plamus, K.; Prikk, A.

It is well known that during firing of oil shale fuel the amount of heat released during its combustion per kg of fuel is significantly affected by the endothermic and exothermic processes taking place in mineral matter. These thermal effects are calcite and dolomite decomposing, marcasite FeS2 oxidising, CaO sulphation and formation of the new minerals. The given paper deals with the experimental study of the influence of these thermal effects of oil shale fuel having different heating value on total amount of heat released during combustion in calorimetric bomb, circulating fluidized bed (CFB) and pulverized-firing boiler (PFB). The large-scale (250 MWth) experiments were performed in the K11-1 CFB boiler of the Balti Power Plant. During experiments low heating value of a fuel varied within the range 8.5-11 MJ/kg. At the end some conclusions were drawn.

Healthcare costs of burn patients from homes without fire sprinklers.

Science.gov (United States)

Banfield, Joanne; Rehou, Sarah; Gomez, Manuel; Redelmeier, Donald A; Jeschke, Marc G

2015-01-01

The treatment of burn injuries requires high-cost services for healthcare and society. Automatic fire sprinklers are a preventive measure that can decrease fire injuries, deaths, property damage, and environmental toxins. This study's aim was to conduct a cost analysis of patients with burn or inhalation injuries caused by residential fires and to compare this with the cost of implementing residential automatic fire sprinklers. We conducted a cohort analysis of adult burn patients admitted to our provincial burn center (1995-2012). Patient demographics and injury characteristics were collected from medical records and clinical and coroner databases. Resource costs included average cost per day at our intensive care and rehabilitation program, transportation, and property loss. During the study period, there were 1557 residential fire-related deaths province-wide and 1139 patients were admitted to our provincial burn center as a result of a flame injury occurring at home. At our burn center, the average cost was CAN$84,678 per patient with a total cost of CAN$96,448,194. All resources totaled CAN$3,605,775,200. This study shows the considerable healthcare costs of burn patients from homes without fire sprinklers.

Control Properties of Bottom Fired Marine Boilers

DEFF Research Database (Denmark)

Solberg, Brian; Andersen, Palle; Karstensen, Claus M. S.

2005-01-01

This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearised versions of the model are analysed to determine how gain, time constants and right half plane zeros (caused by the shrink-and-swell phenomenon) depend on the steam flow load. Furthermore...... the interactions in the system are inspected to analyse potential benefit from using a multivariable control strategy in favour of the current strategy based on single loop theory. An analysis of the nonlinear model is carried out to further determine the nonlinear characteristics of the boiler system...... and to verify whether nonlinear control is needed. Finally a controller based on single loop theory is used to analyse if input constraints become active when rejecting transient behaviour from the disturbance steam flow. The model analysis shows large variations in system gains at steady state as function...

Towards a generic, reliable CFD modelling methodology for waste-fired grate boilers

DEFF Research Database (Denmark)

Rajh, Boštjan; Yin, Chungen; Samec, Niko

of the increased CO2 and H2O vapour concentrations on radiative heat transfer in the boiler. The impacts of full buoyancy on turbulence are also investigated. As a validation effort, the temperature profiles at different ports inside the furnace are measured and the experimental values are compared with the CFD...

Fire-tube boiler optimization criteria and efficiency indicators rational values defining

Science.gov (United States)

Batrakov, P. A.; Mikhailov, A. G.; Ignatov, V. Yu

2018-01-01

Technical and economic calculations problems solving with the aim of identifying the opportunity to recommend the project for industrial implementation are represented in the paper. One of the main determining factors impacting boiler energy efficiency is the exhaust gases temperature, as well as the furnace volume thermal stress. Fire-tube boilers with different types of furnaces are considered in the study. The fullest analysis of the boiler performance thermal and technical indicators for the following engineering problem: Q=idem, M=idem and evaluation according to η, B is presented. The furnace with the finned ellipse profile application results in the fuel consumption decrease due to a more efficient heat exchange surface of the furnace compared to other examined ones.

Emission Characteristics of Gas-Fired Boilers based on Category-Specific Emission Factor from Field Measurements in Beijing, China

Science.gov (United States)

Itahashi, S.; Yan, X.; Song, G.; Yan, J.; Xue, Y.

2017-12-01

Gas-fired boilers will become the main stationary sources of NOx in Beijing. However, the knowledge of gas-fired boilers in Beijing is limited. In the present study, the emission characteristics of NOx, SO2, and CO from gas-fired boilers in Beijing were established using category-specific emission factors (EFs) from field measurements. In order to obtain category-specific EFs, boilers were classified through influence analysis. Factors such as combustion mode, boiler type, and installed capacity were considered critical for establishing EFs because they play significant roles in pollutant formation. The EFs for NOx, CO, and SO2 ranged from 1.42-6.86 g m-3, 0.05-0.67 g m-3 and 0.03-0.48 g m-3. The emissions of NOx, SO2, and CO for gas-fired boilers in Beijing were 11121 t, 468 t, and 222 t in 2014, respectively. The emissions were spatially allocated into grid cells with a resolution of 1 km × 1 km, and the results indicated that top emitters were in central Beijing. The uncertainties were quantified using a Monte Carlo simulation. The results indicated high uncertainties in CO (-157% to 154%) and SO2 (-127% to 182%) emissions, and relatively low uncertainties (-34% to 34%) in NOx emission. Furthermore, approximately 61.2% and 96.8% of the monitored chamber combustion boilers (CCBs) met the standard limits for NOx and SO2, respectively. Concerning NOx, low-NOx burners and NOx emission control measures are urgently needed for implementing of stricter standards. Adopting terminal control measures is unnecessary for SO2, although its concentration occasionally exceeds standard limits, because reduction of its concentration can be achieved thorough control of the sulfur content of natural gas at a stable low level. Furthermore, the atmospheric combustion boilers (ACBs) should be substituted with CCBs, because ACBs have a higher emission despite lower gross installed capacity. The results of this study will enable in understanding and controlling emissions from gas-fired

Global burned area and biomass burning emissions from small fires

NARCIS (Netherlands)

Randerson, J.T; Chen, Y.; van der Werf, G.R.; Rogers, B.M.; Morton, D.C.

2012-01-01

In several biomes, including croplands, wooded savannas, and tropical forests, many small fires occur each year that are well below the detection limit of the current generation of global burned area products derived from moderate resolution surface reflectance imagery. Although these fires often

Fuel characterization requirements for cofiring biomass in coal-fired boilers

International Nuclear Information System (INIS)

Prinzing, D.E.; Tillman, D.A.; Harding, N.S.

1993-01-01

The cofiring of biofuels with coal in existing boilers, or the cofiring of biofuels in combined cycle combustion turbine (CCCT) systems presents significant potential benefits to utilities, including reductions in SO 2 and NO x emissions as a function of reducing the mass flow of sulfur and nitrogen to the boiler, reducing CO 2 emissions from the combustion of fossil fuels; potentially reducing fuel costs both by the availability of wood residues and by the fact that biofuels are exempt from the proposed BTU tax; and providing support to industrial customers from the forest products industry. At the same time, cofiring requires careful attention to the characterization of the wood and coal, both singly and in combination. This paper reviews characterization requirements associated with cofiring biofuels and fossil fuels in boilers and CCCT installations with particular attention not only to such concerns as sulfur, nitrogen, moisture, and Btu content, but also to such issues as total ash content, base/acid ratio of the wood ash and the coal ash, alkali metal content in the wood ash and wood fuel (including converted fuels such as low Btu gas or pyrolytic oil), slagging and fouling indices, ash fusion temperature, and trace metal contents in the wood and coal. The importance of each parameter is reviewed, along with potential consequences of a failure to adequately characterize these parameters. The consequences of these parameters are reviewed with attention to firing biofuels with coal in pulverized coal (PC) and cyclone boilers, and firing biofuels with natural gas in CCCT installations

Effect of kind of solid fuel onto noxious compound emissions in the firing up process of a low output water boiler

International Nuclear Information System (INIS)

Wilk, R.; Szymczyk, J.; Zielinski, Z.; Wystemp, E.

1992-01-01

NO x , SO 2 , CO and polynuclear aromatic hydrocarbon emission tests were carried out during the firing up process of a low output boiler for three kinds of smokeless solid fuels and boiler coal. It has been stated that the use of low emissive fuels in low output boilers did not protect against noxious compound emissions during firing up the boiler. (author). 13 refs, 8 figs, 4 tabs

Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Adams, Bradley R. [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew R. [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance L. [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shig [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

2010-06-01

This report summarizes Year 2 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Year 2 focused extensively on obtaining experimental data from the bench-scale, lab-scale and pilot-scale reactors. These data will be used to refine and validate submodels to be implemented in CFD simulations of full-scale boiler retrofits. Program tasks are on schedule for Year 3 completion. Both Year 2 milestones were completed on schedule and within budget.

Ice & Fire: the Burning Question

DEFF Research Database (Denmark)

van Gelderen, Laurens; Jomaas, Grunde

2017-01-01

With the Arctic opening up to new shipping routes and increased oil exploration and production due to climate change, the risk of an Arctic oil spill is increasing. Of the classic oil spill response methods (mechanical recovery, dispersants and in-situ burning), in-situ burning is considered...... to be particularly a suitable response method in the Arctic. In-situ burning aims to remove the oil from the marine environment by burning it from the water surface. A recent Ph.D. thesis from the Technical University of Denmark has provided some new insights with respect to the fire science behind this response...

Experimental investigation on a 0.35 MWth coal-fired horizontal circulating fluidized bed boiler

Energy Technology Data Exchange (ETDEWEB)

Meng, Aihong; Li, Qinghai; Zhang, Yanguo; Wang, Zhaojun; Dang, Wenda [Tsinghua Univ., Beijing (China); Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering

2013-07-01

The capacities of industrial coal-fired boilers are normally less than 20-30 MWe. And these coal-fired boilers of low capacity are facing the severe situation of low efficiency and heavy environmental pollution. Hence, an innovative horizontal circulating fluidized bed (HCFB) boiler was developed to enhance heat efficiency and reduce pollutant emission of industrial boilers in China. The chamber in the HCFB boiler consists of primary combustion chamber, secondary combustion chamber and burnout chamber, which were combined horizontally side by side. To verify the conception of horizontal fluidized circulation and to obtain the characteristic data, a 0.35 MWth coal-combustion HCFB boiler was designed and installed to perform some experiments of combustion and mass circulation. In the boiler there were two mass circulating paths, one is inner circulating through the inertia separator and another was external circulating through the cyclone separator. The connection bottom of the secondary chamber and the burnout chamber was designed as an inertia separator, in which separated and collected solid materials were returned to the primary combustion. In fact the secondary separator was a small cyclone separator connecting to the exit of the burnout chamber. Heat efficiency and separating efficiency of the experimental boiler were measured and analyzed. Furthermore, mass and temperature distribution along the chambers height were also investigated. The results showed that the heat efficiency of the bare boiler was 82%. The mass balance based on ash content was measured and analyzed. Separating efficiency of the inertia separator and cyclone separator was 60 and 99.9%, respectively. It showed that the two stage material separation and circulation enhanced coal combustion in the HCFB boiler and help to minimize the height of the furnace.

Application of programmable controllers to oil fired boiler light-off system

International Nuclear Information System (INIS)

Copeland, H.C.; Gallaway, E.N.

1978-01-01

A programmable controller has been used to improve the reliability of an oil-fired boiler burner control system. An outdated and failing Germanium discrete transistor logic control system was replaced with a modern solid state large scale integrated circuit programmable controller. The ease of making this conversion at a modest expenditure during a limited boiler outage is explained, as well as pitfalls and problems encountered. Light-off reliability with fuel savings were prime objectives. The boiler, rated at 575,000 lb/hr at 450 psig, is used as a backup steam supply for the dual purpose N Reactor at Hanford, Washington, which supplies 860 MWe to the Bonneville Power Administration and weapons grade Plutonium for the Department of Energy. High reliability in light-off and load ascension from standby is required of the boiler which serves as the backup power supply for the reactor

Nature of fireside deposits in a bagasse and groundnut shell fired 20 MW thermal boiler

International Nuclear Information System (INIS)

Srikanth, S.; Das, S.K.; Ravikumar, B.; Rao, D.S.; Nandakumar, K.; Vijayan, P.

2004-01-01

The nature of deposit formation on the fireside surfaces of the boiler tubes in the various parts (water walls, platen superheater, final superheater, economizer, electrostatic precipitator etc.) of a commercial 20 MW stoker-fired boiler being fired with a mixture of 80% bagasse and 20% groundnut shell has been analyzed. The deposits in the various portions of the boiler were characterized by particle size analysis, chemical analysis, X-ray diffraction and scanning electron microscopy. The deposits were found to be mainly quartz, alkali and alkaline earth silicates and sulfates. From the phase constitution and other microscopic characteristics of the deposit, it can be inferred that the silicates in the deposit formed through inertial impaction and the sulfates formed by vapor phase deposition

Nature of fireside deposits in a bagasse and groundnut shell fired 20 MW thermal boiler

Energy Technology Data Exchange (ETDEWEB)

Srikanth, S.; Rao, D.S. [National Metallurgical Laboratory Madras Centre, Chennai (India); Swapan, S.K.; Das, K.; Ravikumar, B. [National Metallurgical Laboratory, Jamshedpur (India). Materials Characterization Division; Nandakumar, K.; Vijayan, P. [Bharat Heavy Electricals Limited, Tiruchirappalli (India). Research and Development Section

2004-10-01

The nature of deposit formation on the fireside surfaces of the boiler tubes in the various parts (water walls, platen superheater, final superheater, economizer, electrostatic precipitator etc.) of a commercial 20 MW stoker-fired boiler being fired with a mixture of 80% bagasse and 20% groundnut shell has been analyzed. The deposits in the various portions of the boiler were characterized by particle size analysis, chemical analysis, X-ray diffraction and scanning electron microscopy. The deposits were found to be mainly quartz, alkali and alkaline earth silicates and sulfates. From the phase constitution and other microscopic characteristics of the deposit, it can be inferred that the silicates in the deposit formed through inertial impaction and the sulfates formed by vapor phase deposition. (author)

Optimization of grate combustion by means of an IR camera. Final report; Optimering af risteforbraending IR-kamera. Slut rapport

Energy Technology Data Exchange (ETDEWEB)

Didriksen, H.; Jensen, Joergen Peter; Hansen, Joergen (DONG Energy, Fredericia (Denmark)); Clausen, Soennik; Larsen, Henning (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark))

2010-09-15

The target of the project has been to improve the control and regulation of grate-fired straw boilers by involving measuring signals from a specially developed IR camera in a new regulation concept. The project was carried out with the straw boiler at the Avedoere power station. The conclusion has been that it is a very demanding task to develop an IR camera, including software, which must function as a process measuring device for continuous on-line measuring under very demanding conditions in a straw fired boiler. The result showed that this was not possible within the framework of this project. The developed camera has on the other hand proved to be very well suited for measuring campaigns, where the camera is ''manned''/continuously monitored. (Energy 11)

Microfine coal firing results from a retrofit gas/oil-designed industrial boiler

Energy Technology Data Exchange (ETDEWEB)

Patel, R.; Borio, R.W.; Liljedahl, G. [Combustion Engineering, Inc., Windsor, CT (United States)] [and others

1995-11-01

Under US Department of Energy, Pittsburgh Energy Technology Center (PETC) support, the development of a High Efficiency Advanced Coal Combustor (HEACC) has been in progress since 1987 at the ABB Power Plant Laboratories. The initial work on this concept produced an advanced coal firing system that was capable of firing both water-based and dry pulverized coal in an industrial boiler environment.

Landscape Patterns of Burn Severity in the Soberanes Fire of 2016

Science.gov (United States)

Potter, Christopher

2016-01-01

The Soberanes Fire started on July 22, 2016 in Monterey County on the California Central Coast from an illegal campfire. This fire burned for 10 weeks at a record cost of more than $208 million for protection and control. A progressive analysis of the normalized burn ratio from the Landsat satellite showed that the final high burn severity (HBS) area for the Soberanes Fire comprised 22 percent of the total area burned, whereas final moderate burn severity (MBS) area comprised about 10 percent of the total area burned of approximately 53,470 ha (132,130 acres). The resulting landscape pattern of burn severity classes from the 2016 Soberanes Fire revealed that the majority of HBS area was located in the elevation zone between 500 and 1000 m, in the slope zone between 15 percent and 30 percent, or on south-facing aspects.

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

DEFF Research Database (Denmark)

Allegrini, Elisa; Boldrin, Alessio; Jansson, S.

2014-01-01

The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed...... characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements......, polychlorinated dibenzo-. p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections...

Reduction of Nitrogen Oxides Emissions from a Coal-Fired Boiler Unit

Science.gov (United States)

Zhuikov, Andrey V.; Feoktistov, Dmitry V.; Koshurnikova, Natalya N.; Zlenko, Lyudmila V.

2016-02-01

During combustion of fossil fuels a large amount of harmful substances are discharged into the atmospheres of cities by industrial heating boiler houses. The most harmful substances among them are nitrogen oxides. The paper presents one of the most effective technological solutions for suppressing nitrogen oxides; it is arrangement of circulation process with additional mounting of the nozzle directed into the bottom of the ash hopper. When brown high-moisture coals are burnt in the medium power boilers, generally fuel nitrogen oxides are produced. It is possible to reduce their production by two ways: lowering the temperature in the core of the torch or decreasing the excess-air factor in the boiler furnace. Proposed solution includes the arrangement of burning process with additional nozzle installed in the lower part of the ash hopper. Air supply from these nozzles creates vortex involving large unburned fuel particles in multiple circulations. Thereby time of their staying in the combustion zone is prolonging. The findings describe the results of the proposed solution; and recommendations for the use of this technological method are given for other boilers.

Occurrence of polycyclic aromatic hydrocarbons in dust emitted from circulating fluidized bed boilers.

Science.gov (United States)

Kozielska, B; Konieczyńiski, J

2008-11-01

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in granulometric fractions of dust emitted from a hard coal fired circulating fluidized bed (CFB) boiler was investigated. The dust was sampled with the use of a Mark III impactor. In each fraction of dust, by using gas chromatography (GC), 16 selected PAHs and total PAHs were determined and the toxic equivalent B(a)P (TE B(a)P) was computed. The results, recalculated for the standard granulometric fractions, are presented as concentrations and content of the determined PAHs in dust. Distributions of PAHs and their profiles in the granulometric dust fractions were studied also. The PAHs in dust emitted from the CFB boiler were compared with those emitted from mechanical grate boilers; a distinctly lower content of PAHs was found in dust emitted from the former.

Increased combustion stability in modulating biomass boilers for district heating systems

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Gunnar; Hermansson, Roger (eds.) [Lulea Univ. of Technology (Sweden)

2002-09-01

{sub x} and the other with emissions close to the set limits. The Glow Guard worked as desired and will be a useful tool for control of combustion on the grate. The simulation of the processes inside the combustion chamber matches the experimental results well in terms of velocity and temperature. Species concentration were reasonable well described at the exit from the combustion chamber but were poorly described above the fuel bed. The dynamic model based on statistics is capable of reproducing the over-all dynamic behaviour of biofuel-fired boilers.

Analysis of todays best available technology for biomass fired heating plants in the interval 0.5 to 10 MW

International Nuclear Information System (INIS)

Karlsson, Mats-Lennart; Gustavsson, Lennart; Maartensson, D.; Leckner, B.

1998-01-01

The purpose of the present project has been to study today's best available technology for biomass fired heating plants in the interval 0.5 to 10 MW from an emission point of view. Emission measurements have been conducted at 21 plants of different types and sizes, i.e. one stationary fluidized bed, fourteen boilers with moving grates, four boilers with fixed grates, one pellet burner and one boiler with a gasification oven. The plants were fired with different fuels: native fuels like wood chips, bark/sawdust, grass and refined fuels like briquettes and pellets. The plants were chosen to represent the best available and/or the most common technology. The flue gases were analyzed for CO, NO x , Total Hydrocarbons (THC), methane, ethylene, acetylene, ammonia, nitrous oxide, CO 2 and O 2 . The measurements were usually made at the heat loads and operating conditions given at the time of testing. However, in a few cases measurements were made at different loads and air settings

Boiler tube failure prevention in fossil fired boilers

International Nuclear Information System (INIS)

Townsend, R.D.

1993-01-01

It is the common experience of power generating companies worldwide that the main causes of forced outages on power plant are those due to boiler tube failures on fossil units. The main reason for the large number of failures are the severe environmental conditions in fossil boilers as the effects of stress, temperature, temperature gradients, corrosion, erosion and vibration combine to produce degradation of the tube steel. Corrosion by oxidation, by combustion products and by impure boiler water can significantly reduce the tube wall thickness and result in failure of a tube many years before its designed service life. Errors can also occur in the design manufacturer, storage, operation, and maintenance of boiler tubing and the wrong material installed in a critical location can lead to premature failure. Altogether, experts in the US and UK, from many different disciplines, have identified seven broad categories of boiler tube failure mechanisms. 1 tab., 2 figs

Spread and burning behavior of continuous spill fires

DEFF Research Database (Denmark)

Zhao, Jinlong; Huang, Hong; Jomaas, Grunde

2017-01-01

Spill fire experiments with continuous discharge on a fireproof glass sheet were conducted to improve the understanding of spill fire spread and burning. Ethanol was used as the fuel and the discharge rate was varied from 2.8. mL/s to 7.6. mL/s. Three ignition conditions were used...... in the experiments; no ignition, instantaneous ignition and delayed ignition. The spread rate, regression rate, penetrated thermal radiation and the temperature of the bottom glass were analyzed. The experiments clearly show the entire spread process for spill fires. Further, the regression rate of spill fires...... at the quasi-steady burning was lower than that of pool fires and the ratio of the spill fires' regression rate to the pool fires' regression rate was found to be approximately 0.89. With respect to the radiative penetration and the heat conduction between the fuel layer and the glass, a regression rate...

500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide emissions from coal-fired boilers

Energy Technology Data Exchange (ETDEWEB)

Sorge, J.N.; Larrimore, C.L.; Slatsky, M.D.; Menzies, W.R.; Smouse, S.M.; Stallings, J.W.

1997-12-31

This paper discusses the technical progress of a US Department of Energy Innovative Clean Coal Technology project demonstrating advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. The primary objectives of the demonstration is to determine the long-term NOx reduction performance of advanced overfire air (AOFA), low NOx burners (LNB), and advanced digital control optimization methodologies applied in a stepwise fashion to a 500 MW boiler. The focus of this paper is to report (1) on the installation of three on-line carbon-in-ash monitors and (2) the design and results to date from the advanced digital control/optimization phase of the project.

Online Monitoring System of Air Distribution in Pulverized Coal-Fired Boiler Based on Numerical Modeling

Directory of Open Access Journals (Sweden)

Żymełka Piotr

2017-12-01

Full Text Available Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS data.

Online Monitoring System of Air Distribution in Pulverized Coal-Fired Boiler Based on Numerical Modeling

Science.gov (United States)

Żymełka, Piotr; Nabagło, Daniel; Janda, Tomasz; Madejski, Paweł

2017-12-01

Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airflow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air flow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-fired boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass flow rates of secondary air to individual burners and to overfire air (OFA) nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS) data.

Fire hazard after prescribed burning in a gorse shrubland: implications for fuel management.

Science.gov (United States)

Marino, Eva; Guijarro, Mercedes; Hernando, Carmen; Madrigal, Javier; Díez, Carmen

2011-03-01

Prescribed burning is commonly used to prevent accumulation of biomass in fire-prone shrubland in NW Spain. However, there is a lack of knowledge about the efficacy of the technique in reducing fire hazard in these ecosystems. Fire hazard in burned shrubland areas will depend on the initial capacity of woody vegetation to recover and on the fine ground fuels existing after fire. To explore the effect that time since burning has on fire hazard, experimental tests were performed with two fuel complexes (fine ground fuels and regenerated shrubs) resulting from previous prescribed burnings conducted in a gorse shrubland (Ulex europaeus L.) one, three and five years earlier. A point-ignition source was used in burning experiments to assess ignition and initial propagation success separately for each fuel complex. The effect of wind speed was also studied for shrub fuels, and several flammability parameters were measured. Results showed that both ignition and initial propagation success of fine ground fuels mainly depended on fuel depth and were independent of time since burning, although flammability parameters indicated higher fire hazard three years after burning. In contrast, time since burning increased ignition and initial propagation success of regenerated shrub fuels, as well as the flammability parameters assessed, but wind speed had no significant effect. The combination of results of fire hazard for fine ground fuels and regenerated shrubs according to the variation in relative coverage of each fuel type after prescribed burning enabled an assessment of integrated fire hazard in treated areas. The present results suggest that prescribed burning is a very effective technique to reduce fire hazard in the study area, but that fire hazard will be significantly increased by the third year after burning. These results are valuable for fire prevention and fuel management planning in gorse shrubland areas. Copyright © 2010 Elsevier Ltd. All rights reserved.

Development of Cost Effective Oxy-Combustion Retrofitting for Coal-Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Hamid Farzan

2010-12-31

The overall objective of this project is to further develop the oxy-combustion technology for commercial retrofit in existing wall-fired and Cyclone boilers by 2012. To meet this goal, a research project was conducted that included pilot-scale testing and a full-scale engineering and economic analysis.

Waterwall corrosion evaluation in coal-fired boilers using electrochemical measurements

Energy Technology Data Exchange (ETDEWEB)

Davis, K.; Lee, C.; Seeley, R.; Harding, S.; Heap, M.; Cox, W.

2000-07-01

Until recently, waterwall corrosion in North American coal-fired boilers was uncommon and relatively mild. However, the introduction of combustion modifications to reduce in-furnace NOx formation has led to notable increases in the frequency and severity of waterwall wastage. Reaction Engineering International (REI) has worked with the Department of Energy and EPRI to improve predictive capabilities and provide solutions for furnace wall wastage for a wide range of coal-fired furnaces. To date, this work has emphasized computational simulations. More recently, REI in partnership with Corrosion Management has begun complementary efforts to improve their services by evaluating technologies capable of determining the location/rate of high water wall wastage resulting from corrosion. After an evaluation of commercially available options, electrochemical noise (EN) technology has been chosen for continued development. This approach has been successfully applied to corrosion-related problems involving acid dewpoint corrosion in flue gas ductwork, FGD systems, cooling water systems, oil and gas production, and acid cleaning (Cox et al, 1999). This paper presents the results of preliminary testing of an EN probe in a high temperature environment typical of the lower furnace of a cyclone-fired boiler operating under staged conditions. The relationship between electrochemical responses and (1) stoichiometry and (2) local hydrogen sulfide concentration is investigated and the qualitative and quantitative usefulness of the approach for on-line risk management is considered.

Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

Energy Technology Data Exchange (ETDEWEB)

None

2006-06-01

This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

Reduction of Nitrogen Oxides Emissions from a Coal-Fired Boiler Unit

Directory of Open Access Journals (Sweden)

Zhuikov Andrey V.

2016-01-01

Full Text Available During combustion of fossil fuels a large amount of harmful substances are discharged into the atmospheres of cities by industrial heating boiler houses. The most harmful substances among them are nitrogen oxides. The paper presents one of the most effective technological solutions for suppressing nitrogen oxides; it is arrangement of circulation process with additional mounting of the nozzle directed into the bottom of the ash hopper. When brown high-moisture coals are burnt in the medium power boilers, generally fuel nitrogen oxides are produced. It is possible to reduce their production by two ways: lowering the temperature in the core of the torch or decreasing the excess-air factor in the boiler furnace. Proposed solution includes the arrangement of burning process with additional nozzle installed in the lower part of the ash hopper. Air supply from these nozzles creates vortex involving large unburned fuel particles in multiple circulations. Thereby time of their staying in the combustion zone is prolonging. The findings describe the results of the proposed solution; and recommendations for the use of this technological method are given for other boilers.

CONTROL OF NOX EMISSIONS FROM U.S. COAL-FIRED ELECTRIC UTILITY BOILERS

Science.gov (United States)

The paper discusses the control of nitrogen oxide (NOx) emissions from U.S. coal-fired electric utility boilers. (NOTE: In general, NOx control technologies are categorized as being either primary or secondary control technologies. Primary technologies reduce the amount of NOx pr...

Advancing grate-firing for greater environmental impacts and efficiency for decentralized biomass/wastes combustion

DEFF Research Database (Denmark)

Yin, Chungen; Li, Shuangshuang

2017-01-01

to well suit decentralized biomass and municipal/industrial wastes combustion. This paper discusses with concrete examples how to advance grate-firing for greater efficiency and environmental impacts, e.g., use of advanced secondary air system, flue gas recycling and optimized grate assembly, which...

Burn Severities, Fire Intensities, and Impacts to Major Vegetation Types from the Cerro Grande Fire

Energy Technology Data Exchange (ETDEWEB)

Balice, Randy G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, Kathryn D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wright, Marjorie A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2004-12-15

The Cerro Grande Fire resulted in major impacts and changes to the ecosystems that were burned. To partially document these effects, we estimated the acreage of major vegetation types that were burned at selected burn severity levels and fire intensity levels. To accomplish this, we adopted independently developed burn severity and fire intensity maps, in combination with a land cover map developed for habitat management purposes, as a basis for the analysis. To provide a measure of confidence in the acreage estimates, the accuracies of these maps were also assessed. In addition, two other maps of comparable quality were assessed for accuracy: one that was developed for mapping fuel risk and a second map that resulted from a preliminary application of an evolutionary computation software system, called GENIE.

Fire behavior, weather, and burn severity of the 2007 Anaktuvuk River tundra fire, North Slope, Alaska

Science.gov (United States)

Benjamin M. Jones; Crystal A. Kolden; Randi Jandt; John T. Abatzoglu; Frank Urban; Christopher D. Arp

2009-01-01

In 2007, the Anaktuvuk River Fire (ARF) became the largest recorded tundra fire on the North Slope of Alaska. The ARF burned for nearly three months, consuming more than 100,000 ha. At its peak in early September, the ARF burned at a rate of 7000 ha d-1. The conditions potentially responsible for this large tundra fire include modeled record high...

Natural forest fires and controlled burning - a study of the literature

International Nuclear Information System (INIS)

Hoernsten, L.; Nohlgren, E.; Aldentun, Y.

1995-01-01

A study of the literature was made to elucidate the history of forest fires in Sweden. Both the frequency of natural forest fires and the extent of controlled burning as a forest-management technique were examined. The literature revealed that natural forest fires occurred every 40 to 160 years, depending on the type of site and the climatic conditions. Natural forest fires are an unusual occurrence nowadays, mainly thanks to effective fire-fighting methods but also because of the reduction in the quantity of combustible materials left in the stands in modern forestry practice. The report describes the factors influencing the occurrence and frequency of forest fires and the impact these have on flora and fauna. Controlled burning has a long history of use as a method of site preparation prior to natural regeneration. Peak usage of the method occurred in the 1950s and 1960s, since when it has steadily declined. An account is given of the methods used for controlled burning. In parallel with the study, we conducted a questionnaire survey among forest enterprises to identify current interest in controlled burning. The techniques used and the costs involved are discussed. In addition to Sweden, we also looked at controlled burning in Canada, Finland and the USA. Finland is closest to Sweden when it comes to the history of controlled burning and the current interest in fire for conservation purposes. 103 refs, 18 figs

PROTOTYPE SCALE TESTING OF LIMB TECHNOLOGY FOR A PULVERIZED-COAL-FIRED BOILER

Science.gov (United States)

The report summarizes results of an evaluation of furnace sorbent injection (FSI) to control sulfur dioxide (SO2) emissions from coal-fired utility boilers. (NOTE: FSI of calcium-based sorbents has shown promise as a moderate SO2 removal technology.) The Electric Power Research I...

Assessment of the economics of basic natural gas cofiring in coal-fired stoker boilers. Topical report, June 1991-June 1992

International Nuclear Information System (INIS)

Bluestein, J.

1992-06-01

The report analyzes the possible benefits of basic gas cofiring in coal-fired stoker boilers. It presents data on the population of stoker boilers, the potential benefits of basic cofiring in stoker boilers and their value to the boiler operator. In particular, it quantifies the economic value of environmental and operational benefits known or thought to arise from cofiring

Effects of Different Fuel Specifications and Operation Conditions on the Performance of Coated and Uncoated Superheater Tubes in Two Different Biomass-Fired Boilers

DEFF Research Database (Denmark)

Wu, Duoli; Dahl, Kristian V.; Madsen, Jesper L.

2018-01-01

Fireside corrosionis a serious concern in biomass firing powerplants such that the efficiency of boilers is limited by high temperature corrosion. Application of protective coatings on superheater tubes is a possible solution to combat fireside corrosion. The current study investigates the corros......Fireside corrosionis a serious concern in biomass firing powerplants such that the efficiency of boilers is limited by high temperature corrosion. Application of protective coatings on superheater tubes is a possible solution to combat fireside corrosion. The current study investigates...... the corrosion performance of coated tubes compared to uncoated Esshete 1250 and TP347H tubes, which were exposed in two different biomass-fired boilers for one year. Data on the fuel used, temperature of the boilers, and temperature fluctuations are compared for the two boilers, and how these factors influence...... deposit formation, corrosion, and the stability of the coatings is discussed. The coatings (Ni and Ni2Al3) showed protective behavior ina wood-fired plant where the outlet steam temperature was 520 °C. However, at the plant that fired straw with an outlet steam temperature of 540 °C and where severe...

Advanced modelling and testing of a 13 MWth waste wood-fired grate boiler with recycled flue gas

DEFF Research Database (Denmark)

Rajh, Boštjan; Yin, Chungen; Samec, Niko

2016-01-01

as an innovative attempt to improve the boiler performance, a refined weighted-sum-of-grey-gases-model of greater accuracy is developed to better address the impacts of the elevated CO2 and H2O vapour concentrations on radiative heat transfer in the boiler. The impacts of full buoyancy on the turbulent flow...

Mitsubishi latest coal fired USC boiler technology (CFE Pacifico 700 MW)

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T.; Sakamoto, K. [Mitsubishi Heavy Industries, Ltd., Nagasaki (Japan). Power Systems; Fujitab, M. [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan). Power Systems

2013-07-01

Mitsubishi Heavy Industries, Ltd. (MHI) has successfully completed commissioning work for CFE (Comision Federal de Electricidad) Pacifico 700 MW coal-fired unit in March 2010 which is the first supercritical unit in Latin America. This supercritical boiler was designed with state of the art technologies such as low NOx burners, high fineness pulverizers, advanced vertical furnace wall technology and so on. Especially the advanced vertical furnace wall technology with some improvements is a key technology to realize swift load changes such as 5% load per minute ramping rate with assuring dynamic characteristics. Recently the requirement of the high efficiency and the swift load changes for the power boilers has been increased so that even a coal-fired unit needs flexible operation characteristics for balancing variety of power sources. One of the challenges for the swift load change is to keep the furnace wall metal temperature low during the load change, which the advanced vertical furnace wall could realize. The report describes the features of the unit and commissioning result including load swing test results in details.

Increase of Ecological Safety, Reliability and Efficiency of Coal-Fired Boilers

Directory of Open Access Journals (Sweden)

Volkov E.P.

2017-04-01

Full Text Available The changes of environmental legislation of the Russian Federation will lead to a drastic increase of the ecological payments for environmental pollution in excess of technological standards. Significant excess in relative emissions of nitrogen oxides take place in burning solid fuel with liquid slag-tap removal. The purpose of this article was to develop technical solutions for low-cost reconstruction of the boilers to ensure efficient combustion of the fuel and technological standards of emissions of nitrogen oxides. As shown the use of straight-flow burners with compulsory optimization of the aerodynamics of the furnace and the organization of staged combustion of fuel will provide low nitrogen oxide emissions and efficient fuel combustion. Research on physical models has demonstrated the feasibility of increasing the angle of the pulverized coal burners down to 65-70o, and also achieved a more uniform distribution and increase the speed of the jets coming from upper and lower tertiary air vertical compartments of nozzles through the installation of the vertical extra sheets, which guide the flow in a space between jets. The results obtained allow the transfer of existing boilers with slag-tag removal to a solid with the installation of direct-flow burners and optimization of the aerodynamics of the furnace, which provides regulations for energy efficiency and ecological safety corresponding to the best, achieved technologies, and dramatically reduces environmental payments. The proposed technology in boiler BKZ-210-140F allowed reducing emissions of nitrogen oxides by more than 2 times when burning highly reactive Kuznetsk coal, as shown as an example.

Understorey fire frequency and the fate of burned forests in southern Amazonia.

Science.gov (United States)

Morton, D C; Le Page, Y; DeFries, R; Collatz, G J; Hurtt, G C

2013-06-05

Recent drought events underscore the vulnerability of Amazon forests to understorey fires. The long-term impact of fires on biodiversity and forest carbon stocks depends on the frequency of fire damages and deforestation rates of burned forests. Here, we characterized the spatial and temporal dynamics of understorey fires (1999-2010) and deforestation (2001-2010) in southern Amazonia using new satellite-based estimates of annual fire activity (greater than 50 ha) and deforestation (greater than 10 ha). Understorey forest fires burned more than 85 500 km(2) between 1999 and 2010 (2.8% of all forests). Forests that burned more than once accounted for 16 per cent of all understorey fires. Repeated fire activity was concentrated in Mato Grosso and eastern Pará, whereas single fires were widespread across the arc of deforestation. Routine fire activity in Mato Grosso coincided with annual periods of low night-time relative humidity, suggesting a strong climate control on both single and repeated fires. Understorey fires occurred in regions with active deforestation, yet the interannual variability of fire and deforestation were uncorrelated, and only 2.6 per cent of forests that burned between 1999 and 2008 were deforested for agricultural use by 2010. Evidence from the past decade suggests that future projections of frontier landscapes in Amazonia should separately consider economic drivers to project future deforestation and climate to project fire risk.

Backstepping-based nonlinear adaptive control for coal-fired utility boiler-turbine units

International Nuclear Information System (INIS)

Fang, Fang; Wei, Le

2011-01-01

The control system of boiler-turbine unit plays an important role in improving efficiency and reducing emissions of power generation unit. The nonlinear, coupling and uncertainty of the unit caused by varying working conditions should be fully considered during the control system design. This paper presents an efficient control scheme based on backstepping theory for improving load adaptability of boiler-turbines in wide operation range. The design process of the scheme includes model preprocessing, control Lyapunov functions selection, interlaced computation of adaptive control laws, etc. For simplification and accuracy, differential of steam pipe inlet pressure and integral terms of target errors are adopted. Also, to enhance practicality, implementation steps of the scheme are proposed. A practical nonlinear model of a 500 MW coal-fired boiler-turbine unit is used to test the efficiency of the proposed scheme in different conditions.

New fuel air control strategy for reducing NOx emissions from corner-fired utility boilers at medium-low loads

DEFF Research Database (Denmark)

Zhao, Sinan; Fang, Qingyan; Yin, Chungen

2017-01-01

Due to the rapidly growing renewable power, the fossil fuel power plants have to be increasingly operated under large and rapid load change conditions, which can induce various challenges. This work aims to reduce NOx emissions of large-scale corner-fired boilers operated at medium–low loads....... The combustion characteristics and NOx emissions from a 1000 MWe corner-fired tower boiler under different loads are investigated experimentally and numerically. A new control strategy for the annular fuel air is proposed and implemented in the boiler, in which the secondary air admitted to the furnace through...... the air annulus around each coal nozzle tip is controlled by the boiler load, instead of being controlled by the output of the connected mill as commonly used in this kind of power plant. Both the experimental and simulation results show that the new control strategy reduces NOx emissions at the entrance...

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant.

Science.gov (United States)

Allegrini, E; Boldrin, A; Jansson, S; Lundtorp, K; Fruergaard Astrup, T

2014-04-15

The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits. Copyright © 2014 Elsevier B.V. All rights reserved.

Detailed investigation of Cl-corrosion initiated by deposits formed in biomass-fired boilers. Final report

Energy Technology Data Exchange (ETDEWEB)

Frandsen, Flemming J.; Lith, S. van

2009-10-15

The aim was to investigate deposit-induced Cl-corrosion under well-controlled laboratory conditions, simulating the conditions in biomass-fired boilers. This has been done by exposing pieces of superheater tubes, covered by synthetic salts, at temperatures and gas mixtures simulating biomass-fired conditions. The corroded specimens have been studied in detail using a Scanning Electron Microscope (SEM), in order to determine the corrosion rate, and to investigate the chemistry and morphology of the corrosive attack. The project has been divided into four activities: A1: Relationship between the Cl-concentration in the deposit, and the corrosion rate. A2: Influence of cation type (K+ and Na+) on the mobility of Cl in the deposit. A3: Influence of metal temperature on the corrosion rate. A4: Critical evaluation of the existing experience for minimizing corrosion in full-scale boilers firing totally or partly with biomass. (LN)

Optimized scheme in coal-fired boiler combustion based on information entropy and modified K-prototypes algorithm

Science.gov (United States)

Gu, Hui; Zhu, Hongxia; Cui, Yanfeng; Si, Fengqi; Xue, Rui; Xi, Han; Zhang, Jiayu

2018-06-01

An integrated combustion optimization scheme is proposed for the combined considering the restriction in coal-fired boiler combustion efficiency and outlet NOx emissions. Continuous attribute discretization and reduction techniques are handled as optimization preparation by E-Cluster and C_RED methods, in which the segmentation numbers don't need to be provided in advance and can be continuously adapted with data characters. In order to obtain results of multi-objections with clustering method for mixed data, a modified K-prototypes algorithm is then proposed. This algorithm can be divided into two stages as K-prototypes algorithm for clustering number self-adaptation and clustering for multi-objective optimization, respectively. Field tests were carried out at a 660 MW coal-fired boiler to provide real data as a case study for controllable attribute discretization and reduction in boiler system and obtaining optimization parameters considering [ maxηb, minyNOx ] multi-objective rule.

NOx Control Options and Integration for US Coal Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding; Robert Hurt

2003-12-31

This is the fourteenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. Using the initial CFD baseline modeling of the Gavin Station and the plant corrosion maps, six boiler locations for the corrosion probes were identified and access ports have been installed. Preliminary corrosion data obtained appear consistent and believable. In situ, spectroscopic experiments at BYU reported in part last quarter were completed. New reactor tubes have been made for BYU's CCR that allow for testing smaller amounts of catalyst and thus increasing space velocity; monolith catalysts have been cut and a small reactor that can accommodate these pieces for testing is in its final stages of construction. A poisoning study on Ca-poisoned catalysts was begun this quarter. A possible site for a biomass co-firing test of the slipstream reactor was visited this quarter. The slipstream reactor at Rockport required repair and refurbishment, and will be re-started in the next quarter. This report describes the final results of an experimental project at Brown University on the fundamentals of ammonia / fly ash interactions with relevance to the operation of advanced NOx control technologies such as selective catalytic reduction. The Brown task focused on the measurement of ammonia adsorption isotherms on commercial fly ash samples subjected to a variety of treatments and on the chemistry of dry and semi-dry ammonia removal processes.

Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Bradley Adams; Andrew Fry; Constance Senior; Hong Shim; Huafeng Wang; Jost Wendt; Christopher Shaddix

2009-06-30

This report summarizes Year 1 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Through the course of Year 1 activities, great progress was made toward understanding the issues associated with oxy-combustion retrofit of coal-fired boilers. All four Year 1 milestones and objectives have been, or will be, completed on schedule and within budget. Progress in the four milestone areas may be summarized as follows: • University of Utah has performed size segregated ash composition measurements in the Oxy-Fuel Combustor (OFC). These experiments indicate that oxy-combustion retrofit may impact ash aerosol mineral matter composition. Both flame temperature and flue gas composition have been observed to influence the concentration of calcium, magnesium and iron in the fine particulate. This could in turn impact boiler fouling and slagging. • Sandia National Labs has shown that char oxidation rate is dependent on particle size (for sizes between 60 and 100 microns) by performing fundamental simulations of reacting char particles. These predictions will be verified by making time-resolved optical measurements of char particle temperature, velocity and size in bench-scale experiments before the end of Year 1. • REI and Siemens have completed the design of an oxy-research burner that will be mounted on University of Utah’s pilot-scale furnace, the L1500. This burner will accommodate a wide range of O2, FGR and mixing strategies under conditions relevant for utility boiler operation. Through CFD modeling of the different burner designs, it was determined that the key factor influencing flame stabilization location is particle heat-up rate. The new oxy-research burner and associated equipment is scheduled for delivery before the end of Year 1. • REI has completed a literature survey of slagging and

Prescribed burning with spot fires in the Georgia Coastal Plain

Science.gov (United States)

R. W. Johansen

1984-01-01

The use of prescribed fire in the management of pine forests is common throughout much of the South, but one recurring problem that worries the forest landowner is not having enough suitable burning weather to satisfactorily complete all scheduled fires. Being able to burn areas considerably faster, without causing undue damage, could be a solution.

Intelligent emissions controller for substance injection in the post-primary combustion zone of fossil-fired boilers

Science.gov (United States)

Reifman, Jaques; Feldman, Earl E.; Wei, Thomas Y. C.; Glickert, Roger W.

2003-01-01

The control of emissions from fossil-fired boilers wherein an injection of substances above the primary combustion zone employs multi-layer feedforward artificial neural networks for modeling static nonlinear relationships between the distribution of injected substances into the upper region of the furnace and the emissions exiting the furnace. Multivariable nonlinear constrained optimization algorithms use the mathematical expressions from the artificial neural networks to provide the optimal substance distribution that minimizes emission levels for a given total substance injection rate. Based upon the optimal operating conditions from the optimization algorithms, the incremental substance cost per unit of emissions reduction, and the open-market price per unit of emissions reduction, the intelligent emissions controller allows for the determination of whether it is more cost-effective to achieve additional increments in emission reduction through the injection of additional substance or through the purchase of emission credits on the open market. This is of particular interest to fossil-fired electrical power plant operators. The intelligent emission controller is particularly adapted for determining the economical control of such pollutants as oxides of nitrogen (NO.sub.x) and carbon monoxide (CO) emitted by fossil-fired boilers by the selective introduction of multiple inputs of substances (such as natural gas, ammonia, oil, water-oil emulsion, coal-water slurry and/or urea, and combinations of these substances) above the primary combustion zone of fossil-fired boilers.

Comparison of different testing methods for gas fired domestic boiler efficiency determination

International Nuclear Information System (INIS)

De Paepe, M.; T'Joen, C.; Huisseune, H.; Van Belleghem, M.; Kessen, V.

2013-01-01

As the Energy Performance of Buildings Directive is being implemented throughout the European Union, a clear need for certification of boiler and domestic heating devices has arisen. Several ‘Notified Bodies’ exist, spread around the different member states. They are acting as the notified body of that member state and focus on local certification. A boiler manufacturer has its equipment tested according to the ‘Boiler Efficiency directive 92/42/EC’. Recently, tests done by several notified bodies in sequence on an identical unit of a manufacturer showed that results could differ depending on which notified body performed the test. In cooperation with ‘Technigas’ (Notified Body in Belgium) a detailed study was done of the measurement setup and devices for determining boiler efficiencies. Several aspects were studied: measurement devices (absolute or differential types), their location within the test setup (focussing on accuracy and their overall impact on the result) and the measurement strategy (measuring on the primary or the secondary water side). The study was performed for both full load and part load scenarios of a gas fired domestic boiler (smaller than 70 kW [4]). The results clearly indicate that temperature measurements arecritical for assessing boiler efficiency. Secondly the test setup using secondary circuit measurements should be preferred. Tests were performed at ‘Technigas’ on different setups in order to validate the findings. - Highlights: ► Labelling of boiler is now obliged by European standards. ► Error propagation is analysed for different methods of boiler performance testing. ► Secondary water side measurement with separate calibration of has highest quality. ► A sensitivity analysis showed that the water temperatures are important factors.

Neural networks improve performance of coal-fired boilers

Energy Technology Data Exchange (ETDEWEB)

Radl, B.J. [Pegasus Technologies Ltd., Painesville, OH (United States)

1999-03-01

Work sponsored by the US Department of Energy through its NICE{sup 3} programme, and co-funded by industry partners First Energy Corp. (host organisation and co-funder) and Pegasus Technologies (inventor, developer and supplier), has resulted in the development of online, real-time neural networks which help coal-fired utility boilers to dynamically adjust combustion setpoints. The payoff is a system which helps reduce NOx emissions up to 60%, while improving heat rate up to 2% overall. The system has avoided or postponed large capacity expenditures while meeting environmental compliance requirements. 3 figs., 1 tab.

Characterization of biomass burning aerosols from forest fire in Indonesia

Science.gov (United States)

Fujii, Y.; Iriana, W.; Okumura, M.; Lestari, P.; Tohno, S.; Akira, M.; Okuda, T.

2012-12-01

Biomass burning (forest fire, wild fire) is a major source of pollutants, generating an estimate of 104 Tg per year of aerosol particles worldwide. These particles have adverse human health effects and can affect the radiation budget and climate directly and indirectly. Eighty percent of biomass burning aerosols are generated in the tropics and about thirty percent of them originate in the tropical regions of Asia (Andreae, 1991). Several recent studies have reported on the organic compositions of biomass burning aerosols in the tropical regions of South America and Africa, however, there is little data about forest fire aerosols in the tropical regions of Asia. It is important to characterize biomass burning aerosols in the tropical regions of Asia because the aerosol properties vary between fires depending on type and moisture of wood, combustion phase, wind conditions, and several other variables (Reid et al., 2005). We have characterized PM2.5 fractions of biomass burning aerosols emitted from forest fire in Indonesia. During the dry season in 2012, PM2.5 aerosols from several forest fires occurring in Riau, Sumatra, Indonesia were collected on quartz and teflon filters with two mini-volume samplers. Background aerosols in forest were sampled during transition period of rainy season to dry season (baseline period). Samples were analyzed with several analytical instruments. The carbonaceous content (organic and elemental carbon, OC and EC) of the aerosols was analyzed by a thermal optical reflectance technique using IMPROVE protocol. The metal, inorganic ion and organic components of the aerosols were analyzed by X-ray Fluorescence (XRF), ion chromatography and gas chromatography-mass spectrometry, respectively. There was a great difference of chemical composition between forest fire and non-forest fire samples. Smoke aerosols for forest fires events were composed of ~ 45 % OC and ~ 2.5 % EC. On the other hand, background aerosols for baseline periods were

Comparative study of computational intelligence approaches for NOx reduction of coal-fired boiler

International Nuclear Information System (INIS)

Wei, Zhongbao; Li, Xiaolu; Xu, Lijun; Cheng, Yanting

2013-01-01

This paper focuses on NO x emission prediction and operating parameters optimization for coal-fired boilers. Support Vector Regression (SVR) model based on CGA (Conventional Genetic Algorithm) was proposed to model the relationship between the operating parameters and the concentration of NO x emission. Then CGA and two modified algorithms, the Quantum Genetic Algorithm (QGA) and SAGA (Simulated Annealing Genetic Algorithm), were employed to optimize the operating parameters of the coal-fired boiler to reduce NO x emission. The results showed that the proposed SVR model was more accurate than the widely used Artificial Neural Network (ANN) model when employed to predict the concentration of NO x emission. The mean relative error and correlation coefficient calculated by the proposed SVR model were 2.08% and 0.95, respectively. Among the three optimization algorithms implemented in this paper, the SAGA showed superiority to the other two algorithms considering the quality of solution within a given computing time. The SVR plus SAGA method was preferable to predict the concentration of NO x emission and further to optimize the operating parameters to achieve low NO x emission for coal-fired boilers. - Highlights: • The CGA based SVR model is proposed to predict the concentration of NO x emission. • The CGA based SVR model performs better than the widely used ANN model. • CGA and two modified algorithms are compared to optimize the parameters. • The SAGA is preferable for its high quality of solution and low computing time. • The SVR plus SAGA is successfully employed to optimize the operating parameters

Desulphurization in peat-fired circulating and bubbling fluidized bed boilers

Energy Technology Data Exchange (ETDEWEB)

Kouvo, P. [Imatran Voima Oy, Vantaa (Finland); Salmenoja, K. [Kvaerner Pulping Oy, Tampere (Finland)

1997-12-31

The new emission limit values for large combustion plants are under consideration both at the EU level and in Finland. Peat and wood are the only indigenous fuels of Finland. In 1995 appr. 8 % of electricity was produced with peat. The lower heating value of peat is around 10 MJ/kg. The moisture content varies between 35-55 % and sulphur content in dry solids between 0.15-0.35 %. The total peat power capacity of Finland in 1995 was 1400 MW. Because there was not enough information available about the desulphurization of the flue gases from peat-fired fluidized bed boilers, a group of Finnish companies and Ministry of Trade and Industry decided to carry out the full-scale desulphurisation study. In the project the desulphurization with limestone injection into the furnace of two types of peat-fired boilers were studied. The goal of the project was to investigate: what the technically and economically feasible emission level is by limestone injection in the fluidized bed combustion; how the limestone injection affects the other flue gas emissions and the fouling of the boiler and, what the economy of desulphurisation is. The tests were carried out at Kokkola and Kemi power plants in Finland. At Kokkola (108 MW{sub f}) circulating fluidized bed boiler, the emission limit of 200 mg/m{sup 3}n was leached at a Ca/S-molar ratio of appr. 10, with limestone containing 92 % of calcium carbonate, CaCO{sub 3}. At Kemi (267 MW{sub f}) bubbling fluidized bed boiler, the emission limit of 280 mg/m{sup 3}n with limestone containing appr. 95 % of CaCO{sub 3} was reached at a Ca/S-molar ratio of appr. 7.0. Emissions of NO{sub x}, N{sub 2}O, NH{sub 3} and dust after the ESP were not elevated due to the limestone feed. At the Kokkola power plant the NO{sub x} emissions varied from 300 to 400 mg/m{sup 3}n, and, at the Kemi power station the NO{sub x} emissions were around 200 mg/m{sup 3}n. The fouling of the Kemi boiler was found to be significant in the scheduled outage after the test

Pellet wood gasification boiler / Combination boiler. Market review. 7. ed.; Scheitholzvergaser-/Kombikessel. Marktuebersicht

Energy Technology Data Exchange (ETDEWEB)

Uth, Joern

2010-08-15

In the market review under consideration on pellet wood gasification boilers and combination boilers, the Federal Ministry of Food, Agriculture and Consumer Protection (Bonn, Federal Republic of Germany) report on planning and installation of wood-fired heating systems, recommendations regarding to the technical assessment of boiler systems, buffers/combination boilers, prices of pellet wood gasification boilers, data sheets of the compared pellet wood gasification boilers, pellet wood combination boilers, prices of pellet wood combination boilers, data sheets of the compared pellet wood gasification boilers, list of providers.

Market review. Pellet wood gasification boiler / combination boiler. 8. ed.; Marktuebersicht. Scheitholzvergaser-/Kombikessel

Energy Technology Data Exchange (ETDEWEB)

Uth, Joern

2012-01-15

In the market review under consideration on pellet wood gasification boilers and combination boilers, the Federal Ministry of Food, Agriculture and Consumer Protection (Bonn, Federal Republic of Germany) reports on planning and installation of wood-fired heating systems, recommendations regarding to the technical assessment of boiler systems, buffers/combination boilers, prices of pellet wood gasification boilers, data sheets of the compared pellet wood gasification boilers, pellet wood combination boilers, prices of pellet wood combination boilers, data sheets of the compared pellet wood gasification boilers, list of providers.

Environmental performance assessment of utility boiler energy conversion systems

International Nuclear Information System (INIS)

Li, Changchun; Gillum, Craig; Toupin, Kevin; Park, Young Ho; Donaldson, Burl

2016-01-01

Highlights: • Sustainability analyses of utility boilers are performed. • Natural gas fired boilers have the least CO_2 emissions in fossil fueled boilers. • Solar boilers rank last with an emergy yield ratio of 1.2. • Biomass boilers have the best emergy sustainability index. - Abstract: A significant amount of global electric power generation is produced from the combustion of fossil fuels. Steam boilers are one of the most important components for steam and electricity production. The objective of this paper is to establish a theoretical framework for the sustainability analysis of a utility boiler. These analyses can be used by decision-makers to diagnose and optimize the sustainability of a utility boiler. Seven utility boiler systems are analyzed using energy and embodied solar energy (emergy) principles in order to evaluate their environmental efficiencies. They include a subcritical coal fired boiler, a supercritical coal fired boiler, an oil fired boiler, a natural gas fired boiler, a concentrating solar power boiler utilizing a tower configuration, a biomass boiler, and a refuse derived fuel boiler. Their relative environmental impacts were compared. The results show that the natural gas boiler has significantly lower CO_2 emission than an equivalent coal or oil fired boiler. The refuse derived fuel boiler has about the same CO_2 emissions as the natural gas boiler. The emergy sustainability index of a utility boiler system is determined as the measure of its sustainability from an environmental perspective. Our analyses results indicate that the natural gas boiler has a relatively high emergy sustainability index compared to other fossil fuel boilers. Converting existing coal boilers to natural gas boilers is a feasible option to achieve better sustainability. The results also show that the biomass boiler has the best emergy sustainability index and it will remain a means to utilize the renewable energy within the Rankine steam cycle. Before

Gain-Scheduled Control of a Fossil-Fired Power Plant Boiler

DEFF Research Database (Denmark)

Hangstrup, M.; Stoustrup, Jakob; Andersen, Palle

1999-01-01

-scheduling which interpolates between unstable controllers is not allowed using traditional schemes. The results show that a considerable optimization of the conventional controlled system is obtainable. Also the gain-scheduled optimizing controller is seen to have a superior performance compared to the fixed LTI......In this paper the objective is to optimize the control of a coal fired 250 MW power plant boiler. The conventional control system is supplemented with a multivariable optimizing controller operating in parallel with the conventional control system. Due to the strong dependence of the gains...... and dynamics upon the load, it is beneficial to consider a gain-scheduling control approach. Optimization using complex mu synthesis results in unstable LTI controllers in some operating points of the boiler. A recent gain-scheduling approach allowing for unstable fixed LTI controllers is applied. Gain...

Oxy-Combustion Boiler Material Development

Energy Technology Data Exchange (ETDEWEB)

Gagliano, Michael; Seltzer, Andrew; Agarwal, Hans; Robertson, Archie; Wang, Lun

2012-01-31

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year

Oxy-Combustion Boiler Material Development

Energy Technology Data Exchange (ETDEWEB)

Michael Gagliano; Andrew Seltzer; Hans Agarwal; Archie Robertson; Lun Wang

2012-01-31

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO{sub 2} level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to

COST OF SELECTIVE CATALYTIC REDUCTION (SCR) APPLICATION FOR NOX CONTROL ON COAL-FIRED BOILERS

Science.gov (United States)

The report provides a methodology for estimating budgetary costs associated with retrofit applications of selective catalytic reduction (SCR) technology on coal-fired boilers. SCR is a postcombustion nitrogen oxides (NOx) control technology capable of providing NOx reductions >90...

Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

OpenAIRE

Asnavandi, Majid; Kahram, Mohaddeseh; Rezaei, Milad; Rezakhani, Davar

2017-01-01

The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tu...

The largest forest fires in Portugal: the constraints of burned area size on the comprehension of fire severity.

Science.gov (United States)

Tedim, Fantina; Remelgado, Ruben; Martins, João; Carvalho, Salete

2015-01-01

Portugal is a European country with highest forest fires density and burned area. Since beginning of official forest fires database in 1980, an increase in number of fires and burned area as well as appearance of large and catastrophic fires have characterized fire activity in Portugal. In 1980s, the largest fires were just a little bit over 10,000 ha. However, in the beginning of 21st century several fires occurred with a burned area over 20,000 ha. Some of these events can be classified as mega-fires due to their ecological and socioeconomic severity. The present study aimed to discuss the characterization of large forest fires trend, in order to understand if the largest fires that occurred in Portugal were exceptional events or evidences of a new trend, and the constraints of fire size to characterize fire effects because, usually, it is assumed that larger the fire higher the damages. Using Portuguese forest fire database and satellite imagery, the present study showed that the largest fires could be seen at the same time as exceptional events and as evidence of a new fire regime. It highlighted the importance of size and patterns of unburned patches within fire perimeter as well as heterogeneity of fire ecological severity, usually not included in fire regime description, which are critical to fire management and research. The findings of this research can be used in forest risk reduction and suppression planning.

Straw combustion on slow-moving grates - a comparison of model predictions with experimental data

Energy Technology Data Exchange (ETDEWEB)

Kaer, S.K. [Aalborg Univ. (Denmark). Inst. of Energy Technology

2005-03-01

Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ''walking-column'' approach and includes the energy equations for both the fuel and the gas accounting for heat transfer between the two phases. The model gives important insight into the combustion process and provides inlet conditions for a computational fluid dynamics analysis of the freeboard. The model predictions indicate the existence of two distinct combustion modes. Combustion air temperature and mass flow-rate are the two parameters determining the mode. There is a significant difference in reaction rates (ignition velocity) and temperature levels between the two modes. Model predictions were compared to measurements in terms of ignition velocity and temperatures for five different combinations of air mass flow and temperature. In general, the degree of correspondence with the experimental data is favorable. The largest difference between measurements and predictions occurs when the combustion mode changes. The applicability to full-scale is demonstrated by predictions made for an existing straw-fired boiler located in Denmark. (author)

Quantifying soil burn severity for hydrologic modeling to assess post-fire effects on sediment delivery

Science.gov (United States)

Dobre, Mariana; Brooks, Erin; Lew, Roger; Kolden, Crystal; Quinn, Dylan; Elliot, William; Robichaud, Pete

2017-04-01

Soil erosion is a secondary fire effect with great implications for many ecosystem resources. Depending on the burn severity, topography, and the weather immediately after the fire, soil erosion can impact municipal water supplies, degrade water quality, and reduce reservoirs' storage capacity. Scientists and managers use field and remotely sensed data to quickly assess post-fire burn severity in ecologically-sensitive areas. From these assessments, mitigation activities are implemented to minimize post-fire flood and soil erosion and to facilitate post-fire vegetation recovery. Alternatively, land managers can use fire behavior and spread models (e.g. FlamMap, FARSITE, FOFEM, or CONSUME) to identify sensitive areas a priori, and apply strategies such as fuel reduction treatments to proactively minimize the risk of wildfire spread and increased burn severity. There is a growing interest in linking fire behavior and spread models with hydrology-based soil erosion models to provide site-specific assessment of mitigation treatments on post-fire runoff and erosion. The challenge remains, however, that many burn severity mapping and modeling products quantify vegetation loss rather than measuring soil burn severity. Wildfire burn severity is spatially heterogeneous and depends on the pre-fire vegetation cover, fuel load, topography, and weather. Severities also differ depending on the variable of interest (e.g. soil, vegetation). In the United States, Burned Area Reflectance Classification (BARC) maps, derived from Landsat satellite images, are used as an initial burn severity assessment. BARC maps are classified from either a Normalized Burn Ratio (NBR) or differenced Normalized Burned Ratio (dNBR) scene into four classes (Unburned, Low, Moderate, and High severity). The development of soil burn severity maps requires further manual field validation efforts to transform the BARC maps into a product more applicable for post-fire soil rehabilitation activities

BPACK -- A computer model package for boiler reburning/co-firing performance evaluations. User`s manual, Volume 1

Energy Technology Data Exchange (ETDEWEB)

Wu, K.T.; Li, B.; Payne, R.

1992-06-01

This manual presents and describes a package of computer models uniquely developed for boiler thermal performance and emissions evaluations by the Energy and Environmental Research Corporation. The model package permits boiler heat transfer, fuels combustion, and pollutant emissions predictions related to a number of practical boiler operations such as fuel-switching, fuels co-firing, and reburning NO{sub x} reductions. The models are adaptable to most boiler/combustor designs and can handle burner fuels in solid, liquid, gaseous, and slurried forms. The models are also capable of performing predictions for combustion applications involving gaseous-fuel reburning, and co-firing of solid/gas, liquid/gas, gas/gas, slurry/gas fuels. The model package is conveniently named as BPACK (Boiler Package) and consists of six computer codes, of which three of them are main computational codes and the other three are input codes. The three main codes are: (a) a two-dimensional furnace heat-transfer and combustion code: (b) a detailed chemical-kinetics code; and (c) a boiler convective passage code. This user`s manual presents the computer model package in two volumes. Volume 1 describes in detail a number of topics which are of general users` interest, including the physical and chemical basis of the models, a complete description of the model applicability, options, input/output, and the default inputs. Volume 2 contains a detailed record of the worked examples to assist users in applying the models, and to illustrate the versatility of the codes.

Application of an empirical model in CFD simulations to predict the local high temperature corrosion potential in biomass fired boilers

International Nuclear Information System (INIS)

Gruber, Thomas; Scharler, Robert; Obernberger, Ingwald

2015-01-01

To gain reliable data for the development of an empirical model for the prediction of the local high temperature corrosion potential in biomass fired boilers, online corrosion probe measurements have been carried out. The measurements have been performed in a specially designed fixed bed/drop tube reactor in order to simulate a superheater boiler tube under well-controlled conditions. The investigated boiler steel 13CrMo4-5 is commonly used as steel for superheater tube bundles in biomass fired boilers. Within the test runs the flue gas temperature at the corrosion probe has been varied between 625 °C and 880 °C, while the steel temperature has been varied between 450 °C and 550 °C to simulate typical current and future live steam temperatures of biomass fired steam boilers. To investigate the dependence on the flue gas velocity, variations from 2 m·s −1 to 8 m·s −1 have been considered. The empirical model developed fits the measured data sufficiently well. Therefore, the model has been applied within a Computational Fluid Dynamics (CFD) simulation of flue gas flow and heat transfer to estimate the local corrosion potential of a wood chips fired 38 MW steam boiler. Additionally to the actual state analysis two further simulations have been carried out to investigate the influence of enhanced steam temperatures and a change of the flow direction of the final superheater tube bundle from parallel to counter-flow on the local corrosion potential. - Highlights: • Online corrosion probe measurements in a fixed bed/drop tube reactor. • Development of an empirical corrosion model. • Application of the model in a CFD simulation of flow and heat transfer. • Variation of boundary conditions and their effects on the corrosion potential

30 CFR 57.13030 - Boilers.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boilers. 57.13030 Section 57.13030 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13030 Boilers. (a) Fired pressure vessels (boilers) shall be equipped with water level gauges, pressure...

Co-firing straw and coal in a 150-MWe utility boiler: in situ measurements

DEFF Research Database (Denmark)

Hansen, P. F.B.; Andersen, Karin Hedebo; Wieck-Hansen, K.

1998-01-01

A 2-year demonstration program is carried out by the Danish utility I/S Midtkraft at a 150-MWe PF-boiler unit reconstructed for co-firing straw and coal. As a part of the demonstration program, a comprehensive in situ measurement campaign was conducted during the spring of 1996 in collaboration...... with the Technical University of Denmark. Six sample positions have been established between the upper part of the furnace and the economizer. The campaign included in situ sampling of deposits on water/air-cooled probes, sampling of fly ash, flue gas and gas phase alkali metal compounds, and aerosols as well...... deposition propensities and high temperature corrosion during co-combustion of straw and coal in PF-boilers. Danish full scale results from co-firing straw and coal, the test facility and test program, and the potential theoretical support from the Technical University of Denmark are presented in this paper...

Design of 500kW grate fired test facility using CFD

DEFF Research Database (Denmark)

Rosendahl, Lasse Aistrup; Kær, Søren Knudsen; Jørgensen, K.

2005-01-01

A 500kW vibrating grate fired test facility for solid biomass fuels has been designed using numerical models including CFD. The CFD modelling has focussed on the nozzle layout and flowpatterns in the lower part of the furnace, and the results have established confidence in the chosen design...

Assessment of fire-damaged mesquite trees 8 years following an illegal burn

Science.gov (United States)

Gerald J. Gottfried; Peter F. Ffolliott; Pablo Garcia; Diego Valdez-Zamudio; Akram Al-Khouri

2003-01-01

Effects of an illegal burn on the Santa Rita Experimental Range on mesquite (Prosopis velutina) survival in the semidesert grass-shrub ecosystem was initially assessed in terms of firedamage classes 18 months after the fire and again 8 years after the burn. While many of the mesquite trees on the burned site were damaged by the fire, some of the trees appear to have...

Further development of recovery boiler; Soodakattilan kehitystyoe

Energy Technology Data Exchange (ETDEWEB)

Janka, K.; Siiskonen, P.; Sundstroem, K. [Tampella Power Oy, Tampere (Finland)] [and others

1996-12-01

The global model of a recovery boiler was further developed. The aim is to be able to model the velocity, temperature and concentration fields in a boiler. At this moment the model includes submodels for: droplet drying, pyrolysis, char burning, gas burning and for droplet trajectory. The preliminary study of NO{sub x} and fly ash behaviour in a boiler was carried out. The study concerning flow field in the superheater area was carried out a 2-dimensional case in which the inflow parameters were taken from global model of a recovery boiler. Further the prediction methods of fouling in a recovery boiler were developed based on theoretical calculations of smelting behaviour of multicomponent mixtures and measurements at operating recovery boilers. (author)

30 CFR 56.13030 - Boilers.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boilers. 56.13030 Section 56.13030 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13030 Boilers. (a) Fired pressure vessels (boilers) shall be equipped with water level gauges, pressure gauges...

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

International Nuclear Information System (INIS)

Allegrini, E.; Boldrin, A.; Jansson, S.; Lundtorp, K.; Fruergaard Astrup, T.

2014-01-01

Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

Energy Technology Data Exchange (ETDEWEB)

Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Boldrin, A. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark); Jansson, S. [Umeå University, Department of Chemistry, Umeå SE-901 87 (Sweden); Lundtorp, K. [Babcock and Wilcox Vølund A/S, Göteborg (Sweden); Fruergaard Astrup, T. [Technical University of Denmark, Department of Environmental Engineering, Building 115, Lyngby 2800 (Denmark)

2014-04-01

Highlights: • Ash was sampled at 10 different points of the boiler of a waste-to-energy plant. • Samples were analysed for the chemical composition, PCDD/F and leaching behaviour. • Enrichment trends of elements were investigated in relation to boiler conditions. • No significant differences were found between boiler ash samples. - Abstract: The Danish waste management system relies significantly on waste-to-energy (WtE) plants. The ash produced at the energy recovery section (boiler ash) is classified as hazardous waste, and is commonly mixed with fly ash and air pollution control residues before disposal. In this study, a detailed characterization of boiler ash from a Danish grate-based mass burn type WtE was performed, to evaluate the potential for improving ash management. Samples were collected at 10 different points along the boiler's convective part, and analysed for grain size distribution, content of inorganic elements, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF), and leaching of metals. For all samples, PCDD and PCDF levels were below regulatory limits, while high pH values and leaching of e.g. Cl were critical. No significant differences were found between boiler ash from individual sections of the boiler, in terms of total content and leaching, indicating that separate management of individual ash fractions may not provide significant benefits.

Burn Severity Dominates Understory Plant Community Response to Fire in Xeric Jack Pine Forests

Directory of Open Access Journals (Sweden)

Bradley D. Pinno

2016-04-01

Full Text Available Fire is the most common disturbance in northern boreal forests, and large fires are often associated with highly variable burn severities across the burnt area. We studied the understory plant community response to a range of burn severities and pre-fire stand age four growing seasons after the 2011 Richardson Fire in xeric jack pine forests of northern Alberta, Canada. Burn severity had the greatest impact on post-fire plant communities, while pre-fire stand age did not have a significant impact. Total plant species richness and cover decreased with disturbance severity, such that the greatest richness was in low severity burns (average 28 species per 1-m2 quadrat and plant cover was lowest in the high severity burns (average 16%. However, the response of individual plant groups differed. Lichens and bryophytes were most common in low severity burns and were effectively eliminated from the regenerating plant community at higher burn severities. In contrast, graminoid cover and richness were positively related to burn severity, while forbs did not respond significantly to burn severity, but were impacted by changes in soil chemistry with increased cover at pH >4.9. Our results indicate the importance of non-vascular plants to the overall plant community in this harsh environment and that the plant community is environmentally limited rather than recruitment or competition limited, as is often the case in more mesic forest types. If fire frequency and severity increase as predicted, we may see a shift in plant communities from stress-tolerant species, such as lichens and ericaceous shrubs, to more colonizing species, such as certain graminoids.

Composition and Structure of Forest Fire Refugia: What Are the Ecosystem Legacies across Burned Landscapes?

Directory of Open Access Journals (Sweden)

Garrett W. Meigs

2018-05-01

Full Text Available Locations within forest fires that remain unburned or burn at low severity—known as fire refugia—are important components of contemporary burn mosaics, but their composition and structure at regional scales are poorly understood. Focusing on recent, large wildfires across the US Pacific Northwest (Oregon and Washington, our research objectives are to (1 classify fire refugia and burn severity based on relativized spectral change in Landsat time series; (2 quantify the pre-fire composition and structure of mapped fire refugia; (3 in forested areas, assess the relative abundance of fire refugia and other burn severity classes across forest composition and structure types. We analyzed a random sample of 99 recent fires in forest-dominated landscapes from 2004 to 2015 that collectively encompassed 612,629 ha. Across the region, fire refugia extent was substantial but variable from year to year, with an annual mean of 38% of fire extent and range of 15–60%. Overall, 85% of total fire extent was forested, with the other 15% being non-forest. In comparison, 31% of fire refugia extent was non-forest prior to the most recent fire, highlighting that mapped refugia do not necessarily contain tree-based ecosystem legacies. The most prevalent non-forest cover types in refugia were vegetated: shrub (40%, herbaceous (33%, and crops (18%. In forested areas, the relative abundance of fire refugia varied widely among pre-fire forest types (20–70% and structural conditions (23–55%. Consistent with fire regime theory, fire refugia and high burn severity areas were inversely proportional. Our findings underscore that researchers, managers, and other stakeholders should interpret burn severity maps through the lens of pre-fire land cover, especially given the increasing importance of fire and fire refugia under global change.

NOVEL ECONOMICAL HG(0) OXIDATION REAGENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED BOILERS

Science.gov (United States)

The authors have developed a novel economical additive for elemental mercury (Hg0) removal from coal-fired boilers. The oxidation reagent was rigorously tested in a lab-scale fixed-bed column with the Norit America's FGD activated carbon (DOE's benchmark sorbent) in a typical PRB...

DEMONSTRATION OF SORBENT INJECTION TECHNOLOGY ON A WALL-FIRED UTILITY BOILER (EDGEWATER LIMB DEMONSTRATION)

Science.gov (United States)

The report gives results of the full-scale demonstration of Limestone Injection Multistage Burner (LIMB) technology on the coal-fired, 105 MW, Unit 4 boiler at Ohio Edison's Edgewater Station. eveloped as a technology aimed at moderate levels of sulfur dioxide (SO2) and nitrogen ...

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 2: Residual-fired nocogeneration process boiler

Science.gov (United States)

Knightly, W. F.

1980-01-01

Computer generated data on the performance of the cogeneration energy conversion system are presented. Performance parameters included fuel consumption and savings, capital costs, economics, and emissions of residual fired process boilers.

Burning behavior in a poor-ventilation compartment fire - ghosting fire

International Nuclear Information System (INIS)

Sugawa, Osami; Kawagoe, Kunio; Oka, Yasushi

1991-01-01

We investigated compartment fire behavior under poor-ventilation conditions using a methyl alcohol pool fire as the source with a diameter of 30 cm set in a tight box of 2 m (W)x3 m(L)x0.6 m(H). The temperatures in the box and the fuel, gas concentrations of CO, CO 2 , and O 2 , and the fuel consumption rate were measured simultaneously. The burning fuel surface level was kept constant during the test by means of an automatic fuel supply system. It was found that the flame begun to detach from the fuel surface as the oxygen concentration decreased to about 16%, and the color changed to pale blue. The flame detached completely from the fuel and a 'ghosting flame' was observed just under the ceiling which showed a thin pale blue flame and looked line an aurora. The oxygen concentration measured in the ghosting period under the ceiling was 9-10 vol%, and CO 2 was 4.5 vol% so that the oxygen of such concentration acted as in inert gas. CO 2 gas concentration looked almost a single-layer with gradient in the upper half part in ghosting period. Temperatures in the same layer decreased after ghosting occurred with gradient. For poor-ventilated fires, air exchange rate as 1.6-2.4 times/hr was estimated in the test; the burning rate decreased finally to about 1/6 of the fuel controlled fire. It has been tacitly assumed that the flame (reaction zone) and pyrolyzing material area (fuel) exit in almost the same zone, but ghosting fire is not necessarily the case. Therefore, extinguishment of ghosting fire which may occur in an enclosure with fuel and energy rich but poor-ventilation such as a power plant will be extremely difficult. (orig.)

Environment protection by coupling of a municipal waste incinerator to an existing coal fire steam boiler

Energy Technology Data Exchange (ETDEWEB)

Ionel, I.; Stanescu, P.D.O.; Gruescu, C.; Savu, A.; Ungureanu, C. [University of Politehnic Timisoara, Timisoara (Romania)

2006-12-15

The paper offers an analysis of the potential coupling of a municipal waste incinerator in Romania, to an existing coal fired steam boiler. Considering the retention of heavy metals as well as HCl from the waste flue gases before entering the boiler, the simulation analysis of the boiler, under the situation that the gases from the scrubber are introduced, are presented As general conclusion one notes that it is possible to apply the concept even if the analysed case is of less importance, but more potential application are viewed for larger industrial application, for new concepts of modern power plants, to meet EU environmental regulations, especially for CO{sub 2} reduction.

The Fire Locating and Modeling of Burning Emissions (FLAMBE) Project

Science.gov (United States)

Reid, J. S.; Prins, E. M.; Westphal, D.; Richardson, K.; Christopher, S.; Schmidt, C.; Theisen, M.; Eck, T.; Reid, E. A.

2001-12-01

The Fire Locating and Modeling of Burning Emissions (FLAMBE) project was initiated by NASA, the US Navy and NOAA to monitor biomass burning and burning emissions on a global scale. The idea behind the mission is to integrate remote sensing data with global and regional transport models in real time for the purpose of providing the scientific community with smoke and fire products for planning and research purposes. FLAMBE is currently utilizing real time satellite data from GOES satellites, fire products based on the Wildfire Automated Biomass Burning Algorithm (WF_ABBA) are generated for the Western Hemisphere every 30 minutes with only a 90 minute processing delay. We are currently collaborating with other investigators to gain global coverage. Once generated, the fire products are used to input smoke fluxes into the NRL Aerosol Analysis and Prediction System, where advection forecasts are performed for up to 6 days. Subsequent radiative transfer calculations are used to estimate top of atmosphere and surface radiative forcing as well as surface layer visibility. Near real time validation is performed using field data collected by Aerosol Robotic Network (AERONET) Sun photometers. In this paper we fully describe the FLAMBE project and data availability. Preliminary result from the previous year will also be presented, with an emphasis on the development of algorithms to determine smoke emission fluxes from individual fire products. Comparisons to AERONET Sun photometer data will be made.

Relations between combustion, deposition, flue gas temperatures and corrosion in straw-fired boilers

DEFF Research Database (Denmark)

Montgomery, Melanie

2004-01-01

ABSTRACT: Additives trials in three different plants, Sønderborg waste incineration plant and Ensted woodchip and straw firing boiler, are described. Both aluminium silicate containing additives and ammonium sulphate was tested. At Sønderborg, there was a drastic decrease in Cl deposition when...... using an aluminium silicate additive, however the relative chlorine content of the deposits was unchanged. At Ensted woodchip plant, a dosage level of additives was reached which reduced the chlorine flux. For straw firing where the chlorine level in the fuel is higher and the fuel load is greater...

NOx Control Options and Integration for US Coal Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Mike Bockelie; Kevin Davis; Connie Senior Darren Shino; Dave Swenson; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

2004-09-30

This is the seventeenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. The SCR slipstream reactor was assembled and installed at Plant Gadsden this quarter. Safety equipment for ammonia had not been installed at the end of the quarter, but will be installed at the beginning of next quarter. The reactor will be started up next quarter. Four ECN corrosion probes were reinstalled at Gavin and collected corrosion data for approximately one month. Two additional probes were installed and removed after about 30 hours for future profilometry analysis. Preliminary analysis of the ECN probes, the KEMA coupons and the CFD modeling results all agree with the ultrasonic tube test measurements gathered by AEP personnel.

Previous fires moderate burn severity of subsequent wildland fires in two large western US wilderness areas

Science.gov (United States)

Sean A. Parks; Carol Miller; Cara R. Nelson; Zachary A. Holden

2014-01-01

Wildland fire is an important natural process in many ecosystems. However, fire exclusion has reduced frequency of fire and area burned in many dry forest types, which may affect vegetation structure and composition, and potential fire behavior. In forests of the western U.S., these effects pose a challenge for fire and land managers who seek to restore the ecological...

Research into properties of dust from domestic central heating boiler fired with coal and solid biofuels

Directory of Open Access Journals (Sweden)

Konieczyński Jan

2017-06-01

Full Text Available The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.

Boilers, evaporators, and condensers

International Nuclear Information System (INIS)

Kakac, S.

1991-01-01

This book reports on the boilers, evaporators and condensers that are used in power plants including nuclear power plants. Topics included are forced convection for single-phase side heat exchangers, heat exchanger fouling, industrial heat exchanger design, fossil-fuel-fired boilers, once through boilers, thermodynamic designs of fossil fuel-first boilers, evaporators and condensers in refrigeration and air conditioning systems (with respect to reducing CFC's) and nuclear steam generators

Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications

Energy Technology Data Exchange (ETDEWEB)

Levasseur, Armand

2014-01-01

This Topical Report outlines guidelines and key considerations for design and operation of pulverized coal-fired boilers for oxy-combustion. The scope addressed includes only the boiler island, not the entire oxy-fired CO{sub 2} capture plant. These guidelines are primarily developed for tangential-fired boilers and focus on designs capable of dual air and oxy-fired operation. The guidelines and considerations discussed are applicable to both new units and existing boiler retrofits. These guidelines are largely based on the findings from the extensive 15 MW{sub th} pilot testing and design efforts conducted under this project. A summary level description is provided for each major aspect of boiler design impacted by oxy-combustion, and key considerations are discussed for broader application to different utility and industrial designs. Guidelines address the boiler system arrangement, firing system, boiler thermal design, ducting, materials, control system, and other key systems.

CFD analysis of temperature imbalance in superheater/reheater region of tangentially coal-fired boiler

Science.gov (United States)

Zainudin, A. F.; Hasini, H.; Fadhil, S. S. A.

2017-10-01

This paper presents a CFD analysis of the flow, velocity and temperature distribution in a 700 MW tangentially coal-fired boiler operating in Malaysia. The main objective of the analysis is to gain insights on the occurrences in the boiler so as to understand the inherent steam temperature imbalance problem. The results show that the root cause of the problem comes from the residual swirl in the horizontal pass. The deflection of the residual swirl due to the sudden reduction and expansion of the flow cross-sectional area causes velocity deviation between the left and right side of the boiler. This consequently results in flue gas temperature imbalance which has often caused tube leaks in the superheater/reheater region. Therefore, eliminating the residual swirl or restraining it from being diverted might help to alleviate the problem.

Modelling fire frequency and area burned across phytoclimatic regions in Spain using reanalysis data and the Canadian Fire Weather Index System

Science.gov (United States)

Bedia, J.; Herrera, S.; Gutiérrez, J. M.

2013-09-01

We develop fire occurrence and burned area models in peninsular Spain, an area of high variability in climate and fuel types, for the period 1990-2008. We based the analysis on a phytoclimatic classification aiming to the stratification of the territory into homogeneous units in terms of climatic and fuel type characteristics, allowing to test model performance under different climatic and fuel conditions. We used generalized linear models (GLM) and multivariate adaptive regression splines (MARS) as modelling algorithms and temperature, relative humidity, precipitation and wind speed, taken from the ERA-Interim reanalysis, as well as the components of the Canadian Forest Fire Weather Index (FWI) System as predictors. We also computed the standardized precipitation-evapotranspiration index (SPEI) as an additional predictor for the models of burned area. We found two contrasting fire regimes in terms of area burned and number of fires: one characterized by a bimodal annual pattern, characterizing the Nemoral and Oro-boreal phytoclimatic types, and another one exhibiting an unimodal annual cycle, with the fire season concentrated in the summer months in the Mediterranean and Arid regions. The fire occurrence models attained good skill in most of the phytoclimatic zones considered, yielding in some zones notably high correlation coefficients between the observed and modelled inter-annual fire frequencies. Total area burned also exhibited a high dependence on the meteorological drivers, although their ability to reproduce the observed annual burned area time series was poor in most cases. We identified temperature and some FWI system components as the most important explanatory variables, and also SPEI in some of the burned area models, highlighting the adequacy of the FWI system for fire modelling applications and leaving the door opened to the development a more complex modelling framework based on these predictors. Furthermore, we demonstrate the potential usefulness

Performance of double source boiler with coal-fired and solar power tower heat for supercritical power generating unit

International Nuclear Information System (INIS)

Zhang, Maolong; Du, Xiaoze; Pang, Liping; Xu, Chao; Yang, Lijun

2016-01-01

An approach of high-efficiency utilization of solar energy was proposed, by which the high concentrated heat received by the solar tower was integrated to the supercritical coal-fired boiler. Two schemes that solar energy was used to heat superheat steam or subcooled feed water were presented. The thermodynamic and heat transfer models were established. For a practical 660 MW supercritical power generating unit, the standard coal consumption of power generation could be decreased by more than 17 g/kWh by such double source boiler. The drawbacks of both schemes were found and then were amended by adding a flue gas bypass to the boiler. It also can be concluded that the maximum solar contribution of two schemes for the gross power generation are 6.11% and 4.90%, respectively. The solar power efficiency of the re-modified designs were demonstrated be superior to that of PS10. In terms of turbine efficiency, the comparisons with Solar Two plant having similar initial temperature found that the efficiency of Scheme I was 5.25% higher than that of Solar Two while the advantage of Scheme II was existing either. Additionally, in two schemes with flue bypass when the medium was extracted, the thermal efficiency of boiler could be improved as well. - Highlights: • High concentrated solar tower heat is integrated to the supercritical coal-fired boiler. • The double source boiler can use solar energy to heat superheat steam or subcooled feed water. • Power generating coal consumption can be reduced by more than 17 g/kWh by the double source boiler. • The solar contribution of double source boiler for the gross power generation can be as high as 6.11%.

Evaluating spatially explicit burn probabilities for strategic fire management planning

Science.gov (United States)

C. Miller; M.-A. Parisien; A. A. Ager; M. A. Finney

2008-01-01

Spatially explicit information on the probability of burning is necessary for virtually all strategic fire and fuels management planning activities, including conducting wildland fire risk assessments, optimizing fuel treatments, and prevention planning. Predictive models providing a reliable estimate of the annual likelihood of fire at each point on the landscape have...

Burning in Banksia Woodlands: How Does the Fire-Free Period Influence Reptile Communities?

Science.gov (United States)

Valentine, Leonie E.; Reaveley, Alice; Johnson, Brent; Fisher, Rebecca; Wilson, Barbara A.

2012-01-01

Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8–12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis) and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii) preferred long unburnt melaleuca sites (>16 years since last fire, YSLF) compared to recently burnt sites (16 YSLF). The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (35 YSLF) banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF) melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats. PMID:22496806

Burning in banksia woodlands: how does the fire-free period influence reptile communities?

Directory of Open Access Journals (Sweden)

Leonie E Valentine

Full Text Available Fire is an important management tool for both hazard reduction burning and maintenance of biodiversity. The impact of time since last fire on fauna is an important factor to understand as land managers often aim for prescribed burning regimes with specific fire-free intervals. However, our current understanding of the impact of time since last fire on fauna is largely unknown and likely dependent on vegetation type. We examined the responses of reptiles to fire age in banksia woodlands, and the interspersed melaleuca damplands among them, north of Perth, Western Australia, where the current prescribed burning regime is targeting a fire-free period of 8-12 years. The response of reptiles to fire was dependent on vegetation type. Reptiles were generally more abundant (e.g. Lerista elegans and Ctenophorus adelaidensis and specious in banksia sites. Several species (e.g. Menetia greyii, Cryptoblepharus buchananii preferred long unburnt melaleuca sites (>16 years since last fire, YSLF compared to recently burnt sites (16 YSLF. The terrestrial dragon C. adelaidensis and the skink Morethia obscura displayed a strong response to fire in banksia woodlands only. Highest abundances of the dragon were detected in the recently burnt (35 YSLF banksia woodlands, while the skink was more abundant in older sites. Habitats from a range of fire ages are required to support the reptiles we detected, especially the longer unburnt (>16 YSLF melaleuca habitat. Current burning prescriptions are reducing the availability of these older habitats.

Tree-centered spot firing - a technique for prescribed burning beneath standing trees.

Science.gov (United States)

C. Phillip Weatherspoon; George A. Almond; Carl N. Skinner

1989-01-01

Prescribed burning beneath standing trees normally requires efforts to protect residual trees from excessive fire damage. Damage to both crowns and boles is strongly influenced by flame length, a fire characteristic functionally related to fireline intensity (Albini 1976). In a good prescribed burn, therefore, the prescription specifies desired or maximum flame lengths...

Emission of nitrogen oxides from small biomass-fired grate boilers - a literature survey

International Nuclear Information System (INIS)

Olsson, Daniel

1999-05-01

A literature study has been carried out to find mechanisms for control of nitrogen oxide emissions from small-scale biomass fired combustion devices. The underlying nitrogen chemistry has been studied. Three paths of nitrogen oxide formation has been identified: 1. Thermal NO x , 2, Prompt NO x , and, 3. Fuel NO x . Out of these three mechanisms only fuel NO x is of interest, and the others are neglected at the temperature level concerned. The results from this study have been used to identify limitations and possibilities for NO x and CO abatement. A beacon has been to find efficient methods for NO x abatement at the same time as complete burn-out of the fuel is of greatest importance. The NO x abatement work of many of the Swedish manufacturers of small-scale combustion devices is described. This gives valuable insight in the practical possibilities and limitations in strive for low NOx emissions. From the literature and the contacts with manufacturers some factors of great importance for NO x emission control have been identified. These are: * The fuel (nitrogen content, shape, size, the height of the fuel layer and the tendency of the fuel to stick), * The stoichiometry in the volume above the fuel bed (should be 0.6 - 0.8), * The mixing of the gases above the fuel bed, * The mixing of tertiary air into the main gas flow, and * The thermal load of the combustion chamber (residence time). All the secondary measures studied but selective catalytic reduction have been rejected. Selective catalytic reduction could be a possible solution to the NO x emission problem if it is necessary to further lower the emissions from these small-scale biomass combustion devices despite the cost Project report from the program: Small scale combustion of biofuels. 22 refs, 30 figs, 4 tabs

Use of multi-sensor active fire detections to map fires in the United States: the future of monitoring trends in burn severity

Science.gov (United States)

Picotte, Joshua J.; Coan, Michael; Howard, Stephen M.

2014-01-01

The effort to utilize satellite-based MODIS, AVHRR, and GOES fire detections from the Hazard Monitoring System (HMS) to identify undocumented fires in Florida and improve the Monitoring Trends in Burn Severity (MTBS) mapping process has yielded promising results. This method was augmented using regression tree models to identify burned/not-burned pixels (BnB) in every Landsat scene (1984–2012) in Worldwide Referencing System 2 Path/Rows 16/40, 17/39, and 1839. The burned area delineations were combined with the HMS detections to create burned area polygons attributed with their date of fire detection. Within our study area, we processed 88,000 HMS points (2003–2012) and 1,800 Landsat scenes to identify approximately 300,000 burned area polygons. Six percent of these burned area polygons were larger than the 500-acre MTBS minimum size threshold. From this study, we conclude that the process can significantly improve understanding of fire occurrence and improve the efficiency and timeliness of assessing its impacts upon the landscape.

PIV measurements of the turbulence integral length scale on cold combustion flow field of tangential firing boiler

Energy Technology Data Exchange (ETDEWEB)

Wu, Wen-fei; Xie, Jing-xing; Gong, Zhi-jun; Li, Bao-wei [Inner Mongolia Univ. of Science and Technology, Baotou (China). Inner Mongolia Key Lab. for Utilization of Bayan Obo Multi-Metallic Resources: Elected State Key Lab.

2013-07-01

The process of the pulverized coal combustion in tangential firing boiler has prominent significance on improving boiler operation efficiency and reducing NO{sub X} emission. This paper aims at researching complex turbulent vortex coherent structure formed by the four corners jets in the burner zone, a cold experimental model of tangential firing boiler has been built. And by employing spatial correlation analysis method and PIV (Particle Image Velocimetry) technique, the law of Vortex scale distribution on the three typical horizontal layers of the model based on the turbulent Integral Length Scale (ILS) has been researched. According to the correlation analysis of ILS and the temporal average velocity, it can be seen that the turbulent vortex scale distribution in the burner zone of the model is affected by both jet velocity and the position of wind layers, and is not linear with the variation of jet velocity. The vortex scale distribution of the upper primary air is significantly different from the others. Therefore, studying the ILS of turbulent vortex integral scale is instructive to high efficiency cleaning combustion of pulverized coal in theory.

Particle Emission Characteristics of Modern and Old-Type Residential Boilers Fired with Wood Logs and Wood Pellets

International Nuclear Information System (INIS)

Johansson, L.S.; Gustavsson, L.; Tullin, C.; Potter, A.; Leckner, B.

2005-01-01

Residential biofuel combustion for heating can be performed in two ways: in a stove heating the surrounding room, or in a boiler heating water to be circulated through a piping system to heat an entire house. In contrast to stoves, wood boilers can be connected to heat storage tanks, which is an advantage from an emission point of view. The present work focuses on comparing emissions from old-type and modern boilers by means of systematic variation of combustion device, fuel quality, firing behaviour, and the influence of heat storage tank. User habits are simulated in a schematic way. The purpose of the comparison is to determine the emission differences between old-type and modern residential biofuel boilers and to quantify emission characteristics of different kind of biofuel combustion

Model based control of grate combustion; Modellbaserad roststyrning

Energy Technology Data Exchange (ETDEWEB)

Broden, Henrik; Kjellstroem, Bjoern; Niklasson, Fredrik; Boecher Poulsen, Kristian

2006-12-15

An existing dynamic model for grate combustion has been further developed. The model has been used for studies of possible advantages that can be gained from utilisation of measurements of grate temperatures and fuel bed height for control of a boiler after disturbances caused by varying fuel moisture and fuel feeding. The objective was to asses the possibilities to develop a control system that would adjust for such disturbances quicker than measurements of steam output and oxygen in the exhaust. The model is based on dividing the fuel bed into three layers, where the different layers include fuel being dried, fuel being pyrolysed and char reacting with oxygen. The grate below the fuel bed is also considered. A mass balance, an energy balance and a volume balance is considered for each layer in 22 cells along the grate. The energy balances give the temperature distribution and the volume balances the bed height. The earlier version of the model could not handle layers that are consumed. This weakness has now been eliminated. Comparisons between predicted grate temperatures and measurements in a 25 MW boiler fuelled with biofuel have been used for validation of the model. The comparisons include effects of variations in primary air temperature, fuel moisture and output power. The model shows good agreement with observations for changes in the air temperature but the ability of the model to predict effects of changed fuel moisture is difficult to judge since the steam dome pressure control caused simultaneous changes of the primary air flow, which probably had a larger influence on the grate temperature. A linearised, tuned and reduced version of the model was used for design of a linear quadratic controller. This was used for studies of advantages of using measurements of grate temperatures and bed height for control of pusher velocity, grate speed, primary air flow and air temperature after disturbances of fuel moisture and fuel flow. Measurements of the grate

Combustion performance of pyrolysis oil/ethanol blends in a residential-scale oil-fired boiler

Science.gov (United States)

A 40 kWth oil-fired commercial boiler was fueled with blends of biomass pyrolysis oil (py-oil) and ethanol to determine the feasibility of using these blends as a replacement for fuel oil in home heating applications. An optimal set of test parameters was determined for the combustion of these blend...

On changes in bed-material particles from a 550 MWth CFB boiler burning coal, bark and peat

Energy Technology Data Exchange (ETDEWEB)

Vesna Barisic; Mikko Hupa [Aabo Akademi Process Chemistry Centre, Turku (Finland). Combustion and Materials Chemistry

2007-02-15

This paper presents our observations on coating build up, morphology and the elemental composition of bed-material particles collected from a 550 MWth CFB boiler burning coal, bark and peat fuel/fuel mixture. The special focus was on the changes of the elemental composition of coating layer on bed-material particles when different fuels were burned. The results were obtained using a scanning electron microscope coupled with an energy depressive X-ray analyser (SEM/EDX). The results clearly show that properties of bed-material particles are a result of complex interaction between the fuels burned previously, and the fuels used at the time of sampling. Short communication. 8 refs., 1 fig., 2 tabs.

Challenges of assessing fire and burn severity using field measures, remote sensing and modelling

Science.gov (United States)

Penelope Morgan; Robert E. Keane; Gregory K. Dillon; Theresa B. Jain; Andrew T. Hudak; Eva C. Karau; Pamela G. Sikkink; Zachery A. Holden; Eva K. Strand

2014-01-01

Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing...

The burning and smoke release rates of sodium pool fires

International Nuclear Information System (INIS)

Newman, R.N.; Payne, J.F.B.

1976-10-01

The burning rates and smoke release fractions of sodium pool fires have been measured over the pool temperature range 250 0 C to 750 0 C. A theoretical model is derived which satisfactorily predicts the burning rate over the above temperature range. The theory further predicts that the burning rate should be independent of pool diameter, a prediction supported by a comparison of burning rate data from this study and available data from other studies. (author)

A review on biomass as a fuel for boilers

Energy Technology Data Exchange (ETDEWEB)

Saidur, R.; Abelaziz, E.A.; Demirbas, A.; Hossain, M.S.; Mekhilef, S. [University of Malaya, Kuala Lumpur (Malaysia). Dept. of Mechanical Engineering

2011-06-15

Currently, fossil fuels such as oil, coal and natural gas represent the prime energy sources in the world. However, it is anticipated that these sources of energy will deplete within the next 40-50 years. Moreover, the expected environmental damages such as the global warming, acid rain and urban smog due to the production of emissions from these sources have tempted the world to try to reduce carbon emissions by 80% and shift towards utilizing a variety of renewable energy resources (RES) which are less environmentally harmful such as solar, wind, biomass etc. in a sustainable way. Biomass is one of the earliest sources of energy with very specific properties. In this review, several aspects which are associated with burning biomass in boilers have been investigated such as composition of biomass, estimating the higher heating value of biomass, comparison between biomass and other fuels, combustion of biomass, co-firing of biomass and coal, impacts of biomass, economic and social analysis of biomass, transportation of biomass, densification of biomass, problems of biomass and future of biomass. It has been found that utilizing biomass in boilers offers many economical, social and environmental benefits such as financial net saving, conservation of fossil fuel resources, job opportunities creation and CO{sub 2} and NO emissions reduction. However, care should be taken to other environmental impacts of biomass such as land and water resources, soil erosion, loss of biodiversity and deforestation. Fouling, marketing, low heating value, storage and collections and handling are all associated problems when burning biomass in boilers. The future of biomass in boilers depends upon the development of the markets for fossil fuels and on policy decisions regarding the biomass market.

Detecting post-fire burn severity and vegetation recovery using multitemporal remote sensing spectral indices and field-collected composite burn index data in a ponderosa pine forest

Science.gov (United States)

Chen, Xuexia; Vogelmann, James E.; Rollins, Matt; Ohlen, Donald; Key, Carl H.; Yang, Limin; Huang, Chengquan; Shi, Hua

2011-01-01

It is challenging to detect burn severity and vegetation recovery because of the relatively long time period required to capture the ecosystem characteristics. Multitemporal remote sensing data can providemultitemporal observations before, during and after a wildfire, and can improve the change detection accuracy. The goal of this study is to examine the correlations between multitemporal spectral indices and field-observed burn severity, and to provide a practical method to estimate burn severity and vegetation recovery. The study site is the Jasper Fire area in the Black Hills National Forest, South Dakota, that burned during August and September 2000. Six multitemporal Landsat images acquired from 2000 (pre-fire), 2001 (post-fire), 2002, 2003, 2005 and 2007 were used to assess burn severity. The normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized burn ratio (NBR), integrated forest index (IFI) and the differences of these indices between the pre-fire and post-fire years were computed and analysed with 66 field-based composite burn index (CBI) plots collected in 2002. Results showed that differences of NDVI and differences of EVI between the pre-fire year and the first two years post-fire were highly correlated with the CBI scores. The correlations were low beyond the second year post-fire. Differences of NBR had good correlation with CBI scores in all study years. Differences of IFI had low correlation with CBI in the first year post-fire and had good correlation in later years. A CBI map of the burnt area was produced using regression tree models and the multitemporal images. The dynamics of four spectral indices from 2000 to 2007 indicated that both NBR and IFI are valuable for monitoring long-term vegetation recovery. The high burn severity areas had a much slower recovery than the moderate and low burn areas.

40 CFR 266.101 - Management prior to burning.

Science.gov (United States)

2010-07-01

... storage units that store mixtures of hazardous waste and the primary fuel to the boiler or industrial... MANAGEMENT FACILITIES Hazardous Waste Burned in Boilers and Industrial Furnaces § 266.101 Management prior to burning. (a) Generators. Generators of hazardous waste that is burned in a boiler or industrial furnace...

Probe Measurements of Ash Deposit Formation Rate and Shedding in a Biomass Suspension-Fired boiler

DEFF Research Database (Denmark)

Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension-fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...

Post-Fire Regeneration and Diversity Response to Burn Severity in Pinus halepensis Mill. Forests

Directory of Open Access Journals (Sweden)

Sonsoles González-De Vega

2018-05-01

Full Text Available In recent decades, fire regimes have been modified by various factors such as changes in land use, global change or forest management policies. The vulnerability of Mediterranean terrestrial ecosystems is increasing due to more severe and frequent droughts. This study aimed to determine the plant response of ecosystems during the short-term post-fire period by relating alpha diversity, floristic richness and tree recruitment dynamics to burn severity 5 years after a wildfire. Our results conclude that in the short term, Pinus halepensis Mill. stands in southeastern Spain quickly recovered alpha diversity values, mainly in areas burned with low severity. We observed that moderate and high severities affected the ecosystem more significantly, showing higher values for the Shannon Index but lower for the Simpson index. Pine recruitment was higher in burned areas, and we found the highest number of Aleppo pine seedlings under a moderate burn severity. Post-fire regeneration functional groups (obligate seeders and resprouters were promoted under moderate and high burn severity, increasing their abundance. Annual species (mainly herbs colonized burned areas, persisting with higher presence under moderate burn severity. Restoration tools should be focused on reducing fire severity, mainly in areas at high risk of desertification, and promoting resistance, vulnerability and resilience of these ecosystems.

Effects of Burn Severity and Environmental Conditions on Post-Fire Regeneration in Siberian Larch Forest

Directory of Open Access Journals (Sweden)

Thuan Chu

2017-03-01

Full Text Available Post-fire forest regeneration is strongly influenced by abiotic and biotic heterogeneity in the pre- and post-fire environments, including fire regimes, species characteristics, landforms, hydrology, regional climate, and soil properties. Assessing these drivers is key to understanding the long-term effects of fire disturbances on forest succession. We evaluated multiple factors influencing patterns of variability in a post-fire boreal Larch (Larix sibirica forest in Siberia. A time-series of remote sensing images was analyzed to estimate post-fire recovery as a response variable across the burned area in 1996. Our results suggested that burn severity and water content were primary controllers of both Larch forest recruitment and green vegetation cover as defined by the forest recovery index (FRI and the fractional vegetation cover (FVC, respectively. We found a high rate of Larch forest recruitment in sites of moderate burn severity, while a more severe burn was the preferable condition for quick occupation by vegetation that included early seral communities of shrubs, grasses, conifers and broadleaf trees. Sites close to water and that received higher solar energy during the summer months showed a higher rate of both recovery types, defined by the FRI and FVC, dependent on burn severity. In addition to these factors, topographic variables and pre-fire condition were important predictors of post-fire forest patterns. These results have direct implications for the post-fire forest management in the Siberian boreal Larch region.

[Combustion zone investigation and modelling in fuel flexible suspension fired boilers]. Result summary and status

Energy Technology Data Exchange (ETDEWEB)

Lovmand Hvid, S.

2011-12-15

The project has been designed to obtain data from a power plant boiler with co-combustion, partly to gain greater knowledge of particle turnover in the fuel zone, partly to support the development of modeling tools. Data collection occurred at Studstrup Power Station Unit 4, where the fuel is a combination of coal and biomass. The boiler is equipped with 24 dust burners, four of which have been converted to firing with biomass. Measurements have been carried out in the flame zone with different fuels: coal alone, coal + straw and coal + wood. During the experiments velocity fields, temperature fields and gas concentration fields were measured in the firing zone. Also, particle samples from the flame zone ware collected. Several measurements are performed with well-known techniques, but in addition, the project developed new optical measurement methods based on UV spectroscopy. They allow measuring other gases than the hitherto known methods and allow you to gain insight into the dynamic variations beyond just mean fields. The collection of particle samples from the boiler was, as expected, a very challenging task under the given conditions, but was carried out with a largely satisfactory result. Analysis of the samples has initially failed to lead to an increased recognition of the speed of the conversion process, but the samples will be analyzed in more detail in other projects. (LN)

Pre-fire treatment effects and post-fire forest dynamics on the Rodeo-Chediski burn area, Arizona

Science.gov (United States)

Barbara A. Strom

2005-01-01

The 2002 Rodeo-Chediski fire was the largest wildfire in Arizona history at 189,000 ha (468,000 acres), and exhibited some of the most extreme fire behavior ever seen in the Southwest. Pre-fire fuel reduction treatments of thinning, timber harvesting, and prescribed burning on the White Mountain Apache Tribal lands (WMAT) and thinning on the Apache-Sitgreaves National...

Burning transformations: Fire history effects on organic matter processing from hillslopes to streams

Science.gov (United States)

Barnes, R. T.; Gilbertson, A.; Maxwell, K.

2017-12-01

Disturbance strongly regulates material and energy flows, changing ecosystem pattern and process. An increase in the size and severity of fire, particularly in the Intermountain West, over the last several decades is expected to continue due to a warming climate. Predicting how fire will alter the net ecosystem carbon balance requires us to understand how carbon is stored, processed, and transferred. Here we present results from paired watersheds focused on five 2002 severe fires in Colorado to examine how organic matter is processed along the hillslope and within the stream. Comparing soil samples and water extractable organic matter (WEOM) between burned and unburned sites illustrates the impact of fire: burned soils have 50% organic matter (OM) content as unburned soils, regardless of geomorphic position. While a smaller pool, soil OM (SOM) in burned sites is more susceptible to microbial degradation (pmineral rich, organic poor, portion of the soil. Interestingly, the systematic shifts in OM amounts and quality (as measured by SUVA, E2:E3, and fluorescence) within the terrestrial system in response to fire, are not seen in stream exports. As such, while there are significant relationships (p<0.05) between stream DOM quality, DOM bioavailability, and stream metabolism, burned watersheds are not exporting DOM that is more bioavailable. In addition, despite different terrestrial OM pools, burned and unburned watersheds export statistically similar amounts of DOM per unit area, suggesting that a larger fraction of OM is transferred from the terrestrial to aquatic ecosystem within fire affected landscapes.

40 CFR 761.71 - High efficiency boilers.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false High efficiency boilers. 761.71... PROHIBITIONS Storage and Disposal § 761.71 High efficiency boilers. (a) To burn mineral oil dielectric fluid containing a PCB concentration of ≥50 ppm, but boiler shall comply with the following...

Burned Area Detection and Burn Severity Assessment of a Heathland Fire in Belgium Using Airborne Imaging Spectroscopy (APEX

Directory of Open Access Journals (Sweden)

Lennert Schepers

2014-02-01

Full Text Available Uncontrolled, large fires are a major threat to the biodiversity of protected heath landscapes. The severity of the fire is an important factor influencing vegetation recovery. We used airborne imaging spectroscopy data from the Airborne Prism Experiment (APEX sensor to: (1 investigate which spectral regions and spectral indices perform best in discriminating burned from unburned areas; and (2 assess the burn severity of a recent fire in the Kalmthoutse Heide, a heathland area in Belgium. A separability index was used to estimate the effectiveness of individual bands and spectral indices to discriminate between burned and unburned land. For the burn severity analysis, a modified version of the Geometrically structured Composite Burn Index (GeoCBI was developed for the field data collection. The field data were collected in four different vegetation types: Calluna vulgaris-dominated heath (dry heath, Erica tetralix-dominated heath (wet heath, Molinia caerulea (grass-encroached heath, and coniferous woodland. Discrimination between burned and unburned areas differed among vegetation types. For the pooled dataset, bands in the near infrared (NIR spectral region demonstrated the highest discriminatory power, followed by short wave infrared (SWIR bands. Visible wavelengths performed considerably poorer. The Normalized Burn Ratio (NBR outperformed the other spectral indices and the individual spectral bands in discriminating between burned and unburned areas. For the burn severity assessment, all spectral bands and indices showed low correlations with the field data GeoCBI, when data of all pre-fire vegetation types were pooled (R2 maximum 0.41. Analysis per vegetation type, however, revealed considerably higher correlations (R2 up to 0.78. The Mid Infrared Burn Index (MIRBI had the highest correlations for Molinia and Erica (R2 = 0.78 and 0.42, respectively. In Calluna stands, the Char Soil Index (CSI achieved the highest correlations, with R2 = 0

MODIS derived fire characteristics and aerosol optical depth variations during the agricultural residue burning season, north India

International Nuclear Information System (INIS)

Vadrevu, Krishna Prasad; Ellicott, Evan; Badarinath, K.V.S.; Vermote, Eric

2011-01-01

Agricultural residue burning is one of the major causes of greenhouse gas emissions and aerosols in the Indo-Ganges region. In this study, we characterize the fire intensity, seasonality, variability, fire radiative energy (FRE) and aerosol optical depth (AOD) variations during the agricultural residue burning season using MODIS data. Fire counts exhibited significant bi-modal activity, with peak occurrences during April-May and October-November corresponding to wheat and rice residue burning episodes. The FRE variations coincided with the amount of residues burnt. The mean AOD (2003-2008) was 0.60 with 0.87 (+1σ) and 0.32 (-1σ). The increased AOD during the winter coincided well with the fire counts during rice residue burning season. In contrast, the AOD-fire signal was weak during the summer wheat residue burning and attributed to dust and fossil fuel combustion. Our results highlight the need for 'full accounting of GHG's and aerosols', for addressing the air quality in the study area. - Highlights: → MODIS data could capture rice and wheat residue burning events. → The total FRP was high during the rice burning season than the wheat. → MODIS AOD variations coincided well with rice burning events than wheat. → AOD values exceeding one suggested intense air pollution. - This research work highlights the satellite derived fire products and their potential in characterizing the agricultural residue burning events and air pollution.

What determines area burned in large landscapes? Insights from a decade of comparative landscape-fire modelling

Science.gov (United States)

Geoffrey J. Cary; Robert E. Keane; Mike D. Flannigan; Ian D. Davies; Russ A. Parsons

2015-01-01

Understanding what determines area burned in large landscapes is critical for informing wildland fire management in fire-prone environments and for representing fire activity in Dynamic Global Vegetation Models. For the past ten years, a group of landscape-fire modellers have been exploring the relative influence of key determinants of area burned in temperate and...

Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

Science.gov (United States)

Saqib, Naeem; Bäckström, Mattias

2014-12-01

Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Satellite versus ground-based estimates of burned area: A comparison between MODIS based burned area and fire agency reports over North America in 2007

Science.gov (United States)

Stephane Mangeon; Robert Field; Michael Fromm; Charles McHugh; Apostolos Voulgarakis

2015-01-01

North American wildfire management teams routinely assess burned area on site during firefighting campaigns; meanwhile, satellite observations provide systematic and global burned-area data. Here we compare satellite and ground-based daily burned area for wildfire events for selected large fires across North America in 2007 on daily timescales. In a sample of 26 fires...

Spreaders, igniters, and burning shrubs: plant flammability explains novel fire dynamics in grass-invaded deserts.

Science.gov (United States)

Fuentes-Ramirez, Andres; Veldman, Joseph W; Holzapfel, Claus; Moloney, Kirk A

2016-10-01

Novel fire regimes are an important cause and consequence of global environmental change that involve interactions among biotic, climatic, and human components of ecosystems. Plant flammability is key to these interactions, yet few studies directly measure flammability or consider how multiple species with different flammabilities interact to produce novel fire regimes. Deserts of the southwestern United States are an ideal system for exploring how novel fire regimes can emerge when fire-promoting species invade ecosystems comprised of species that did not evolve with fire. In these deserts, exotic annual grasses provide fuel continuity across landscapes that did not historically burn. These fires often ignite a keystone desert shrub, the fire-intolerant creosote bush, Larrea tridentata (DC.) Coville. Ignition of Larrea is likely catalyzed by fuels produced by native plants that grow beneath the shrubs. We hypothesize that invasive and native species exhibit distinct flammability characteristics that in combination determine spatial patterns of fire spread and intensity. We measured flammability metrics of Larrea, two invasive grasses, Schismus arabicus and Bromus madritensis, and two native plants, the sub-shrub Ambrosia dumosa and the annual herb Amsinckia menziesii. Results of laboratory experiments show that the grasses carry fire quickly (1.32 cm/s), but burn for short duration (0.5 min) at low temperatures. In contrast, native plants spread fire slowly (0.12 cm/s), but burn up to eight times longer (4 min) and produced hotter fires. Additional experiments on the ignition requirements of Larrea suggest that native plants burn with sufficient temperature and duration to ignite dead Larrea branches (time to ignition, 2 min; temperature at ignition 692°C). Once burning, these dead branches ignite living branches in the upper portions of the shrub. Our study provides support for a conceptual model in which exotic grasses are "spreaders" of fire and native

A decadal glimpse on climate and burn severity influences on ponderosa pine post-fire recovery

Science.gov (United States)

Newingham, B. A.; Hudak, A. T.; Bright, B. C.; Smith, A.; Khalyani, A. H.

2016-12-01

Climate change is predicted to affect plants at the margins of their distribution. Thus, ecosystem recovery after fire is likely to vary with climate and may be slowest in drier and hotter areas. However, fire regime characteristics, including burn severity, may also affect vegetation recovery. We assessed vegetation recovery one and 9-15 years post-fire in North American ponderosa pine ecosystems distributed across climate and burn severity gradients. Using climate predictors derived from downscaled 1993-2011 climate normals, we predicted vegetation recovery as indicated by Normalized Burn Ratio derived from 1984-2012 Landsat time series imagery. Additionally, we collected field vegetation measurements to examine local topographic controls on burn severity and post-fire vegetation recovery. At a regional scale, we hypothesized a positive relationship between precipitation and recovery time and a negative relationship between temperature and recovery time. At the local scale, we hypothesized southern aspects to recovery slower than northern aspects. We also predicted higher burn severity to slow recovery. Field data found attenuated ponderosa pine recovery in hotter and drier regions across all burn severity classes. We concluded that downscaled climate data and Landsat imagery collected at commensurate scales may provide insight into climate effects on post-fire vegetation recovery relevant to ponderosa pine forest managers.

Performance of casting aluminum-silicon alloy condensing heating exchanger for gas-fired boiler

Science.gov (United States)

Cao, Weixue; Liu, Fengguo; You, Xue-yi

2018-01-01

Condensing gas boilers are widely used due to their high heat efficiency, which comes from their ability to use the recoverable sensible heat and latent heat in flue gas. The condensed water of the boiler exhaust has strong corrosion effect on the heat exchanger, which restricts the further application of the condensing gas boiler. In recent years, a casting aluminum-silicon alloy (CASA), which boasts good anti-corrosion properties, has been introduced to condensing hot water boilers. In this paper, the heat transfer performance, CO and NOx emission concentrations and CASA corrosion resistance of a heat exchanger are studied by an efficiency bench test of the gas-fired boiler. The experimental results are compared with heat exchangers produced by Honeywell and Beka. The results show that the excess air coefficient has a significant effect on the heat efficiency and CO and NOx emission of the CASA water heater. When the excess air coefficient of the CASA gas boiler is 1.3, the CO and NOx emission concentration of the flue gas satisfies the design requirements, and the heat efficiency of water heater is 90.8%. In addition, with the increase of heat load rate, the heat transfer coefficient of the heat exchanger and the heat efficiency of the water heater are increased. However, when the heat load rate is at 90%, the NOx emission in the exhaust gas is the highest. Furthermore, when the temperature of flue gas is below 57 °C, the condensation of water vapor occurs, and the pH of condensed water is in the 2.5 5.5 range. The study shows that CASA water heater has good corrosion resistance and a high heat efficiency of 88%. Compared with the heat exchangers produced by Honeywell and Beka, there is still much work to do in optimizing and improving the water heater.

Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

Science.gov (United States)

Oksa, M.; Metsäjoki, J.; Kärki, J.

2015-01-01

There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

Low cost combustion tuning and fuel nozzles modification to reduce NOx emission in large coal-fired boilers

Energy Technology Data Exchange (ETDEWEB)

B. Chudnovsky; L. Levin; A. Talanker; E. Bar-Ziv; A. Vikhansky; A.F. Sarofim [Israel Electric Corporation (IEC), Haifa (Israel)

2003-07-01

This work focuses on low-cost combustion tuning to reduce NOx emission in coal-fired tangential boilers, testing the furnace in various operation modes. We have also experimented different coal nozzle types. The measurements were accompanied by computer simulations of the combustion process. We also used an on-line supervision system. The data obtained from 575 MW boilers show that with tuning and modified nozzles NOx was considerably reduced. The emission of NOx was reduced from 1200 to 570 mg/dNm{sup 3} at 6% O{sub 2} for South African coal at full load. At partial load NOx emission dropped from 1400 to 750-850 mg/dNm{sup 3} at 6% O{sub 2}. High volatile coal firing led to additional NOx reduction. A series of tests were performed with Colombian and Indonesian coals as well, dropping NOx emission to 400-450 mg/dNm{sup 3} at6% O{sub 2} at full load. Sootblowing optimization using the supervision system enabled us to further reduce NOx emission by approximately 10%. The boiler and unit performance was not influenced by any of the techniques used for NOx reduction. In such a manner, the results presented in this work clearly show that technological methods for reduction NOx are available and capable of obtaining the required NOx emission. We believe that the conclusions of the present study are general and may be applied to other utility boilers as well. 13 refs., 12 figs., 7 tabs.

Experimental on fly ash recirculation with bottom feeding to improve the performance of a circulating fluidized bed boiler co-burning coal sludge

Energy Technology Data Exchange (ETDEWEB)

Duan, Lunbo; Xu, Guiling; Liu, Daoyin; Chen, Xiaoping; Zhao, Changsui [Southeast Univ., Nanjing (China). School of Energy and Environment

2013-07-01

With the aim of reducing carbon content in fly ash, fly ash recirculation with bottom feeding (FARBF) technology was applied to a 75 t/h Circulating Fluidized Bed (CFB) boiler burning mixture of coal and coal sludge. And industrial experiments were carried out to investigate the influence of FARBF technology on the combustion performance and pollutant emission characteristics of the CFB boiler. Results show that as the recirculation rate of fly ash increases, the CFB dense bed temperature decreases while the furnace outlet temperature increases, and the temperature distribution in the furnace becomes uniform. Compared with the conditions without fly ash recirculation, the combustion efficiency increases from 92 to 95% when the recirculation rate increases to 8 t/h, and the desulfurization efficiency also increases significantly. As the recirculation rate increases, the emissions of NO and CO decrease, but the particulate emission increases. The present study indicates that FARBF technology can improve the combustion performance and desulfurization efficiency for the CFB boilers burning coal sludge, and this can bring large economical and environmental benefits in China.

Normalized burn ratios link fire severity with patterns of avian occurrence

Science.gov (United States)

Rose, Eli T.; Simons, Theodore R.; Klein, Rob; McKerrow, Alexa

2016-01-01

ContextRemotely sensed differenced normalized burn ratios (DNBR) provide an index of fire severity across the footprint of a fire. We asked whether this index was useful for explaining patterns of bird occurrence within fire adapted xeric pine-oak forests of the southern Appalachian Mountains.ObjectivesWe evaluated the use of DNBR indices for linking ecosystem process with patterns of bird occurrence. We compared field-based and remotely sensed fire severity indices and used each to develop occupancy models for six bird species to identify patterns of bird occurrence following fire.MethodsWe identified and sampled 228 points within fires that recently burned within Great Smoky Mountains National Park. We performed avian point counts and field-assessed fire severity at each bird census point. We also used Landsat™ imagery acquired before and after each fire to quantify fire severity using DNBR. We used non-parametric methods to quantify agreement between fire severity indices, and evaluated single season occupancy models incorporating fire severity summarized at different spatial scales.ResultsAgreement between field-derived and remotely sensed measures of fire severity was influenced by vegetation type. Although occurrence models using field-derived indices of fire severity outperformed those using DNBR, summarizing DNBR at multiple spatial scales provided additional insights into patterns of occurrence associated with different sized patches of high severity fire.ConclusionsDNBR is useful for linking the effects of fire severity to patterns of bird occurrence, and informing how high severity fire shapes patterns of bird species occurrence on the landscape.

ASSESSMENT OF CONTROL TECHNOLOGIES FOR REDUCING EMISSIONS OF SO2 AND NOX FROM EXISTING COAL-FIRED UTILITY BOILERS

Science.gov (United States)

The report reviews information and estimated costs on 15 emissioncontrol technology categories applicable to existing coal-fired electric utility boilers. he categories include passive controls such as least emission dispatching, conventional processes, and emerging technologies ...

[Hazard evaluation modeling of particulate matters emitted by coal-fired boilers and case analysis].

Science.gov (United States)

Shi, Yan-Ting; Du, Qian; Gao, Jian-Min; Bian, Xin; Wang, Zhi-Pu; Dong, He-Ming; Han, Qiang; Cao, Yang

2014-02-01

In order to evaluate the hazard of PM2.5 emitted by various boilers, in this paper, segmentation of particulate matters with sizes of below 2. 5 microm was performed based on their formation mechanisms and hazard level to human beings and environment. Meanwhile, taking into account the mass concentration, number concentration, enrichment factor of Hg, and content of Hg element in different coal ashes, a comprehensive model aimed at evaluating hazard of PM2.5 emitted by coal-fired boilers was established in this paper. Finally, through utilizing filed experimental data of previous literatures, a case analysis of the evaluation model was conducted, and the concept of hazard reduction coefficient was proposed, which can be used to evaluate the performance of dust removers.

Intensification of combustion in wood product industry; Huonekaluteollisuuden laemmityskattiloiden polton tehostaminen

Energy Technology Data Exchange (ETDEWEB)

Larjava, K.; Siltanen, T. [VTT Chemical Technology, Espoo (Finland); Metsae, A. [Suomen Puututkimus Oy, Espoo (Finland); Tormonen, K. [VTT Chemical Technology, Espoo (Finland); Kolsi, A.; Orjala, M. [VTT Energy, Jyvaeskylae (Finland); Muurinen, M. [Enemi Oy, Lahti (Finland)

1995-12-31

The study involved optimization of the burning process in furniture industry boilers and reduction of noxious emissions by simple remedies and adjustments. This was realized in four boilers whose initial concentration of carbon monoxide (CO) in the flue gas was 1500-2000 ppm. In addition some other similar boilers were measured and tuned. As a result, emissions due to incomplete burning diminished. The concentration of carbon monoxide in flue gas during the turning off phase was in the range 3 000 - 30 000 ppm in the on/off controlled boilers. It was observed that the CO-level in the flue gas correlated with the amount of fuel left on the grate at the end of each full output sequence. The emissions during the turning-off phase could not be reduced. Grate and control equipment showed defects and malfunction originating from negligence of maintenance and lack of proper operating instructions. The emissions from maintained boilers were reduced by adjusting the fuel stream and the primary and secondary air flows, with brickwork in the furnace over the grate and by insulating the secondary burning chamber. The flow adjustments were carried out on the basis of flue gas analysis. Mounting a catalyst into the convection part of one tested boiler reduced the CO concentration in of flue gas from the initial value 500 ppm to 300 ppm. However the tested catalyst was poisoned by pollutants in the wood chips. In addition to improving the burning phase, the total emissions of one boiler were minimised by removing the turning off phase completely and changing the burning to a continuous process. This required that the boiler automation was renewed and new automation equipment

Intensification of combustion in wood product industry; Huonekaluteollisuuden laemmityskattiloiden polton tehostaminen

Energy Technology Data Exchange (ETDEWEB)

Larjava, K; Siltanen, T [VTT Chemical Technology, Espoo (Finland); Metsae, A [Suomen Puututkimus Oy, Espoo (Finland); Tormonen, K [VTT Chemical Technology, Espoo (Finland); Kolsi, A; Orjala, M [VTT Energy, Jyvaeskylae (Finland); Muurinen, M [Enemi Oy, Lahti (Finland)

1996-12-31

The study involved optimization of the burning process in furniture industry boilers and reduction of noxious emissions by simple remedies and adjustments. This was realized in four boilers whose initial concentration of carbon monoxide (CO) in the flue gas was 1500-2000 ppm. In addition some other similar boilers were measured and tuned. As a result, emissions due to incomplete burning diminished. The concentration of carbon monoxide in flue gas during the turning off phase was in the range 3 000 - 30 000 ppm in the on/off controlled boilers. It was observed that the CO-level in the flue gas correlated with the amount of fuel left on the grate at the end of each full output sequence. The emissions during the turning-off phase could not be reduced. Grate and control equipment showed defects and malfunction originating from negligence of maintenance and lack of proper operating instructions. The emissions from maintained boilers were reduced by adjusting the fuel stream and the primary and secondary air flows, with brickwork in the furnace over the grate and by insulating the secondary burning chamber. The flow adjustments were carried out on the basis of flue gas analysis. Mounting a catalyst into the convection part of one tested boiler reduced the CO concentration in of flue gas from the initial value 500 ppm to 300 ppm. However the tested catalyst was poisoned by pollutants in the wood chips. In addition to improving the burning phase, the total emissions of one boiler were minimised by removing the turning off phase completely and changing the burning to a continuous process. This required that the boiler automation was renewed and new automation equipment

NOx Control Options and Integration for US Coal Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

2004-03-31

This is the fifteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. At AEP's Gavin Plant, data from the corrosion probes showed that corrosion rate increased as boiler load was increased. During an outage at the plant, the drop in boiler load, sensor temperature and corrosion rate could all be seen clearly. Restarting the boiler saw a resumption of corrosion activity. This behavior is consistent with previous observations made at a 600MWe utility boiler. More data are currently being examined for magnitudes of corrosion rates and changes in boiler operating conditions. Considerable progress was made this quarter in BYU's laboratory study of catalyst deactivation. Surface sulfation appears to partially suppress NO adsorption when the catalyst is not exposed to NH3; NH3 displaces surface-adsorbed NO on SCR catalysts and surface sulfation increases the amount of adsorbed NH3, as confirmed by both spectroscopy and TPD experiments. However, there is no indication of changes in catalyst activity despite changes in the amount of adsorbed NH3. A monolith test reactor (MTR), completed this quarter, provided the first comparative data for one of the fresh and field-exposed monolith SCR catalysts yet developed in this project. Measurements of activity on one of the field-exposed commercial monolith catalysts do not show significant changes in catalyst activity (within experimental error) as compared to the fresh catalyst. The exposed surface of the sample contains large amounts of Ca and Na, neither of which is present in the fresh sample, even after removal of visibly obvious fouling deposits. However, these fouling compounds do

Assessing variability and long-term trends in burned area by merging multiple satellite fire products

Directory of Open Access Journals (Sweden)

L. Giglio

2010-03-01

Full Text Available Long term, high quality estimates of burned area are needed for improving both prognostic and diagnostic fire emissions models and for assessing feedbacks between fire and the climate system. We developed global, monthly burned area estimates aggregated to 0.5° spatial resolution for the time period July 1996 through mid-2009 using four satellite data sets. From 2001–2009, our primary data source was 500-m burned area maps produced using Moderate Resolution Imaging Spectroradiometer (MODIS surface reflectance imagery; more than 90% of the global area burned during this time period was mapped in this fashion. During times when the 500-m MODIS data were not available, we used a combination of local regression and regional regression trees developed over periods when burned area and Terra MODIS active fire data were available to indirectly estimate burned area. Cross-calibration with fire observations from the Tropical Rainfall Measuring Mission (TRMM Visible and Infrared Scanner (VIRS and the Along-Track Scanning Radiometer (ATSR allowed the data set to be extended prior to the MODIS era. With our data set we estimated that the global annual area burned for the years 1997–2008 varied between 330 and 431 Mha, with the maximum occurring in 1998. We compared our data set to the recent GFED2, L3JRC, GLOBCARBON, and MODIS MCD45A1 global burned area products and found substantial differences in many regions. Lastly, we assessed the interannual variability and long-term trends in global burned area over the past 13 years. This burned area time series serves as the basis for the third version of the Global Fire Emissions Database (GFED3 estimates of trace gas and aerosol emissions.

Test firing and emissions analysis of densified RDF (d-RDF) in a small power boiler

International Nuclear Information System (INIS)

Olson, B.A.; Chehaske, J.T.; Meadows, F.; Owens, H.J.; Yoest, H.H.

1991-01-01

A test program to determine the feasibility of burning densified refuse-derived fuel in a small power boiler has been successfully completed. The first phase of the contract entailed assembly and assessment of information on d-RDF combustion from other studies, compilation of existing and proposed regulations for the seven sponsoring Great Lakes states: Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio, and Wisconsin, location of d-RDF and waste paper pellet manufacturers in the region, and fuel supply/test site selection. The second phase entailed conducting test burns with two types of d-RDF composed of municipal solid waste (MSW) and one type of d-RDF composed of waste cardboard. The tests were conducted at a small boiler located at Dordt College in Sioux Center, Iowa. The boiler is not equipped with any pollution control equipment and the emission measurements therefore represent those from an uncontrolled source. Results demonstrated that a particulate control system is required to meet the standard set by Iowa for less than 0.6 lbs particulate matter per million BTU heat input. With the planned addition of a baghouse system for control, the facility should meet all existing State limits for emissions levels. Air toxics concentrations including metals, dioxins, furans, and PCBs were low relative to other municipal waste combustors and will be further reduced after installation of baghouse filter equipment. The key remaining concerns relate to the acceptable level of HCl emissions which are a strong function of the plastic content of fuel raw material and SO 2 which varies widely with fuel raw material composition

Quantification of Ash Deposit Build-up and Removal in a Straw and Wood Suspension-Fired Boiler

DEFF Research Database (Denmark)

Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

2011-01-01

The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension­fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...

Fire Resistant Materials

Science.gov (United States)

1982-01-01

Fire hazard is greater in atmospheres containing a high percentage of oxygen under pressure. NASA intensified its fire safety research after a 1967 Apollo fire. A chemically treated fabric called Durette developed by Monsanto Company, which will not burn or produce noxious fumes, was selected as a material for Apollo astronaut garments. Monsanto sold production rights for this material to Fire Safe Products (FSP). Durette is now used for a wide range of applications such as: sheets, attendants' uniforms in hyperbaric chambers; crew's clothing, furniture and interior walls of diving chambers operated by the U.S. Navy and other oceanographic companies and research organizations. Pyrotect Safety Equipment, Minneapolis, MN produces Durette suits for auto racers, refuelers and crew chiefs from material supplied by FSP. FSP also manufactures Durette bags for filtering gases and dust from boilers, electric generators and similar systems. Durette bags are an alternative to other felted fiber capable of operating at high temperature that cost twice as much.

Forest fires in Mediterranean countries: CO2 emissions and mitigation possibilities through prescribed burning.

Science.gov (United States)

Vilén, Terhi; Fernandes, Paulo M

2011-09-01

Forest fires are an integral part of the ecology of the Mediterranean Basin; however, fire incidence has increased dramatically during the past decades and fire is expected to become more prevalent in the future due to climate change. Fuel modification by prescribed burning reduces the spread and intensity potential of subsequent wildfires. We used the most recently published data to calculate the average annual wildfire CO(2) emissions in France, Greece, Italy, Portugal and Spain following the IPCC guidelines. The effect of prescribed burning on emissions was calculated for four scenarios of prescribed burning effectiveness based on data from Portugal. Results show that prescribed burning could have a considerable effect on the carbon balance of the land use, land-use change and forestry (LULUCF) sector in Mediterranean countries. However, uncertainty in emission estimates remains large, and more accurate data is needed, especially regarding fuel load and fuel consumption in different vegetation types and fuel layers and the total area protected from wildfire per unit area treated by prescribed burning, i.e. the leverage of prescribed burning.

The performance of oil-fired boilers: The influence of fuel sulfur on emissions and appliance integrity

International Nuclear Information System (INIS)

Lee, S.W.

1997-01-01

ASHRAE research project RP-757 examined the impact of distillate fuel sulfur content on the energy and emission performance of oil-fired boilers. The project involved construction of a combustion test rig housed in a constant-temperature test room; installation of a 102.5 kW (350,000 Btu/h) capacity, steel hot water boiler equipped with a special test section to simulate boiler heat exchanger surfaces; introduction of continuous emission analyzers and data-acquisition/control systems; and preparation of specific test fuel oils in the 0.01% to 1.2% sulfur range. The combustion experiments provided comprehensive data including flue gas composition, total deposit weight on test heat exchanger surfaces, pH, sulfite and sulfate in the flue gas condensate and soluble deposits, and iron and sulfur in soluble and insoluble deposits. Controlled combustion experiments using the experimental boiler and fuels have provided the following observations for a systematic increase of boiler fuel sulfur: the flue gas SO 2 increased linearly; the acidity and concentrations of sulfite and sulfate in flue gas condensate and the soluble deposits increased; total surface deposits, which are made up of the soluble and insoluble portions, increased linearly; higher amounts of soluble iron sulfates formed with apparent increased corrosion potential of metal surfaces; and the boiler efficiency remained unchanged during the short-term combustion experiments

A bottom-up method to develop pollution abatement cost curves for coal-fired utility boilers

International Nuclear Information System (INIS)

Vijay, Samudra; DeCarolis, Joseph F.; Srivastava, Ravi K.

2010-01-01

This paper illustrates a new method to create supply curves for pollution abatement using boiler-level data that explicitly accounts for technology cost and performance. The Coal Utility Environmental Cost (CUECost) model is used to estimate retrofit costs for five different NO x control configurations on a large subset of the existing coal-fired, utility-owned boilers in the US. The resultant data are used to create technology-specific marginal abatement cost curves (MACCs) and also serve as input to an integer linear program, which minimizes system-wide control costs by finding the optimal distribution of NO x controls across the modeled boilers under an emission constraint. The result is a single optimized MACC that accounts for detailed, boiler-specific information related to NO x retrofits. Because the resultant MACCs do not take into account regional differences in air-quality standards or pre-existing NO x controls, the results should not be interpreted as a policy prescription. The general method as well as NO x -specific results presented here should be of significant value to modelers and policy analysts who must estimate the costs of pollution reduction.

Advanced process control for solid fuel boilers. Phase 2; Avancerad processtyrning av fastbraensleeldade rostpannor. Etapp 2

Energy Technology Data Exchange (ETDEWEB)

Ehleskog, Rickard; Lundborg, Rickard; Schuster, Robert; Wrangensten, Lars [AaF-Energikonsult AB, Stockholm (Sweden)

2002-04-01

AaF-Energikonsult AB runs within the research programme 'Applied combustion technology' a bigger project under the title 'Possibilities to improved operation of forest-industrial bark boilers by optimised combustion control'. In the project several measures have been identified, that can help to improve the conditions favourable for the combustion and fluid dynamic, for four selected reference grate boilers and grate boilers in general. The boiler at Billerud's paper mill, which is underlying to this project in several ways, is now being rebuilt. During the modifications of the boiler the existing control system will be modified with modern technique to enable operation with low emissions. The new control system consists of several parts, of witch the IR-based ones for fuel input and grate feeding are two totally separated systems. The pressure of the dome, i.e. the effect of the boiler, is the most superior parameter, and is regulated with the combustion air. Amounts of secondary and tertiary air are quoted to the total combustion airflow. The primary oxygen level is primarily regulated with the tertiary air. But if this won't be done without the tertiary air to diverge from de defined working area, the secondary air will assist. The oxygen set point is constantly decreasing until the CO-level exceeds a defined level. Then, the set point will be momentary increased. CFD-calculations have been performed for the modified boiler in Karlsborg for two different loads. The simulations clearly show that the flue gases have a more even retention time in the modified boiler and that the flow pattern is significantly improved. However, concentration gradients of oxygen and temperature gradients still exist. The conclusion is that there is a potential for further improving of the air and flue gas control strategies. The following new control strategies are proposed in the project based on conventional analyse technology; If the furnace

The impact of antecedent fire area on burned area in southern California coastal ecosystems

Science.gov (United States)

Price, Owen F.; Bradstock, Ross A.; Keeley, Jon E.; Syphard, Alexandra D.

2012-01-01

Frequent wildfire disasters in southern California highlight the need for risk reduction strategies for the region, of which fuel reduction via prescribed burning is one option. However, there is no consensus about the effectiveness of prescribed fire in reducing the area of wildfire. Here, we use 29 years of historical fire mapping to quantify the relationship between annual wildfire area and antecedent fire area in predominantly shrub and grassland fuels in seven southern California counties, controlling for annual variation in weather patterns. This method has been used elsewhere to measure leverage: the reduction in wildfire area resulting from one unit of prescribed fire treatment. We found little evidence for a leverage effect (leverage = zero). Specifically our results showed no evidence that wildfire area was negatively influenced by previous fires, and only weak relationships with weather variables rainfall and Santa Ana wind occurrences, which were variables included to control for inter-annual variation. We conclude that this is because only 2% of the vegetation burns each year and so wildfires rarely encounter burned patches and chaparral shrublands can carry a fire within 1 or 2 years after previous fire. Prescribed burning is unlikely to have much influence on fire regimes in this area, though targeted treatment at the urban interface may be effective at providing defensible space for protecting assets. These results fit an emerging global model of fire leverage which position California at the bottom end of a continuum, with tropical savannas at the top (leverage = 1: direct replacement of wildfire by prescribed fire) and Australian eucalypt forests in the middle (leverage ∼ 0.25).

Vegetation fires, absorbing aerosols and smoke plume characteristics in diverse biomass burning regions of Asia

International Nuclear Information System (INIS)

Vadrevu, Krishna Prasad; Lasko, Kristofer; Giglio, Louis; Justice, Chris

2015-01-01

In this study, we explored the relationships between the satellite-retrieved fire counts (FC), fire radiative power (FRP) and aerosol indices using multi-satellite datasets at a daily time-step covering ten different biomass burning regions in Asia. We first assessed the variations in MODIS-retrieved aerosol optical depths (AOD’s) in agriculture, forests, plantation and peat land burning regions and then used MODIS FC and FRP (hereafter FC/FRP) to explain the variations in AOD characteristics. Results suggest that tropical broadleaf forests in Laos burn more intensively than the other vegetation fires. FC/FRP-AOD correlations in different agricultural residue burning regions did not exceed 20% whereas in forest regions they reached 40%. To specifically account for absorbing aerosols, we used Ozone Monitoring Instrument-derived aerosol absorption optical depth (AAOD) and UV aerosol index (UVAI). Results suggest relatively high AAOD and UVAI values in forest fires compared with peat and agriculture fires. Further, FC/FRP could explain a maximum of 29% and 53% of AAOD variations, whereas FC/FRP could explain at most 33% and 51% of the variation in agricultural and forest biomass burning regions, respectively. Relatively, UVAI was found to be a better indicator than AOD and AAOD in both agriculture and forest biomass burning plumes. Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations data showed vertically elevated aerosol profiles greater than 3.2–5.3 km altitude in the forest fire plumes compared to 2.2–3.9 km and less than 1 km in agriculture and peat-land fires, respectively. We infer the need to assimilate smoke plume height information for effective characterization of pollutants from different sources. (letter)

Optimization of a lignite-fired open pulverizing system boiler process based on variations in the drying agent composition

International Nuclear Information System (INIS)

Ma, Youfu; Zhang, Hua; Yuan, Yichao; Wang, Zhiyun

2015-01-01

This paper evaluates three lignite-fired OPSB (open pulverizing system boiler) processes, named OPSB-A, OPSB-B and OPSB-C, corresponding to three options of drying agents used for the pulverizing systems. OPSB-B is similar to our previous work [18] on drying agent composition. Performances of the three OPSBs were calculated and compared with a 600 MW lignite-fired boiler as the reference. The results showed that the coal savings of OPSB-A and OPSB-C were 5.41% and 4.06% in comparison with the reference boiler, whereas for OPSB-B, the savings was 2.57%. Accordingly, emissions of each OPSB could be reduced in proportion to the coal savings. Among the three OPSBs, OPSB-C showed the best performance of water recovery from mill-exhausts because it had the highest mill-exhaust water dew point of 73.2 °C, whereas the exhaust dew points of OPSB-A and OPSB-B were 63.9 °C and 70.9 °C, respectively. Both OPSB-C and OPSB-B are beneficial for achieving a high mill-exhaust humidity ratio, which facilitates water recovery from the mill-exhaust, and a low oxygen content in mill-exhaust, which improves the operating safety of the pulverizing systems, whereas OPSB-A is relatively inferior in these respects. The OPSB-C process is recommended for engineering applications because of its favorable overall performances. - Highlights: • Three lignite-fired OPSB processes are analyzed based on a conventional 600 MW boiler. • OPSB-A, OPSB-B and OPSB-C show coal savings of 5.41%, 2.57 and 4.06%, respectively. • All OPSBs have a great advantage of water recovery from the flue gas, especially OPSB-C. • OPSB-C process is recommended in view of its favorable overall performances

Examination of flame length for burning pulverized coal in laminar flow reactor

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Dong; Kim, Gyu Bo; Chang, Young June; Song, Ju Hun; Jeon, Chung Hwan [Pusan National University, Busan (Korea, Republic of)

2010-12-15

Because there has been a recent increase in the use of low calorific coal compared to standard coal, it is crucial to control the char flame length governing the burning life-time of coal in a coal-fired utility boiler. The main objective of this study is to develop a simplified model that can theoretically predict the flame length for burning coal in a laboratory-scale entrained laminar flow reactor (LFR) system. The char burning behavior was experimentally observed when sub-bituminous pulverized coal was fed into the LFR under burning conditions similar to those in a real boiler: a heating rate of 1000 K/s, an oxygen molar fraction of 7.7 %, and reacting flue gas temperatures ranging from 1500 to 2000 K. By using the theoretical model developed in this study, the effect of particle size on the coal flame length was exclusively addressed. In this model, the effect of particle mass was eliminated to compare with the experimental result performed under a constant mass feeding of coal. Overall, the computed results for the coal flame length were in good agreement with the experimental data, particularly when the external oxygen diffusion effect was considered in the model

Examination of flame length for burning pulverized coal in laminar flow reactor

International Nuclear Information System (INIS)

Kim, Jae Dong; Kim, Gyu Bo; Chang, Young June; Song, Ju Hun; Jeon, Chung Hwan

2010-01-01

Because there has been a recent increase in the use of low calorific coal compared to standard coal, it is crucial to control the char flame length governing the burning life-time of coal in a coal-fired utility boiler. The main objective of this study is to develop a simplified model that can theoretically predict the flame length for burning coal in a laboratory-scale entrained laminar flow reactor (LFR) system. The char burning behavior was experimentally observed when sub-bituminous pulverized coal was fed into the LFR under burning conditions similar to those in a real boiler: a heating rate of 1000 K/s, an oxygen molar fraction of 7.7 %, and reacting flue gas temperatures ranging from 1500 to 2000 K. By using the theoretical model developed in this study, the effect of particle size on the coal flame length was exclusively addressed. In this model, the effect of particle mass was eliminated to compare with the experimental result performed under a constant mass feeding of coal. Overall, the computed results for the coal flame length were in good agreement with the experimental data, particularly when the external oxygen diffusion effect was considered in the model

Radiological investigation in the boiler's maintenance operations in a Coal-Fired power plant

International Nuclear Information System (INIS)

Robles, Beatriz; Mora, Juan C.; Cancio, David; Baeza, Antonio; Corbacho, Jose A.

2008-01-01

As part of a study being performed in the four biggest coal-fired power plants in Spain, the formation of scales of radioisotopes in parts of the heat recovery system was investigated. This effect should be more important in the case of 210 Po and 210 Pb. Thereby, it is likely in given specific chemical conditions that scales could be formed with a high concentration of 210 Pb, probably in secular equilibrium with 210 Po and 210 Bi. Those scales could reach activity concentrations of some hundreds of Bq g -1 . In order to study within the boiler this scale formation, an investigation during the maintenance operations programmed in the 'Compostilla' coal-fired power plant (Ponferrada-Spain) was carried out. Those operations are performed each 2-3 years and last for around 30 or 40 days. Measurements of ambient dose equivalent (H * (10)) in the boiler before and after the entrance of the operators, together with beta surface contamination on the bottom ashes attached in the walls and on the tubes, were performed. The last measurements were carried out for screening purposes in order to select those areas on the tubes which could present Po scales. Even if chemical conditions are in general oxidising within the boiler, since conditions are not homogeneous, some zones were localized in which surface contamination was measured. In these spots, samples were collected and then measured in the laboratory. Moreover, an analysis of maintenance tasks, used personal protection equipment, working times and other important parameters was also carried out. This analysis is important in order to perform radiological evaluations, as realistic as possible, of the effective doses that could be received by maintenance operators. In the present study, the values of the measurements performed and the results of the assessment of the effective doses for the workers are presented. (author)

Correlation of the corrosion rates of steels in a straw fired boiler with the thermodynamically predicted trend of KOH(g) in the flue gases

International Nuclear Information System (INIS)

Blomberg, Tom

2012-01-01

The thermodynamic stability of KOH(g) in flue gases without sulfur and chlorine compounds was studied. Relatively good correlation of the thermodynamically predicted trend of KOH(g) in the flue gases and the literature data of the corrosion rates of different steels in a straw fired boiler was found. A discussion on a possible, physically reasonable mechanism is also presented. However, the causality of the found correlation requires further studies. Highlights: ► Corrosion rates in a straw boiler correlate with the predicted trend of KOH(g). ► KOH(g) impinging the surface may be an important factor in corrosion in straw fired boilers. ► The proposed mechanism may be relevant also to other biomass fuels that release potassium hydroxide during combustion.

Physical characterization of biomass fuels prepared for suspension firing in utility boilers for CFD modelling

DEFF Research Database (Denmark)

Rosendahl, Lasse; Yin, Chungen; Kær, Søren Knudsen

2007-01-01

A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boiler has been analyzed for the purpose of generating size and shape distribution functions applicable to numerical modelling of combustion processes involving biomass, characterised by highly anisotropic...... shapes. The sample is subdivided by straw type, and coherent size, type and mass distribution parameters are reported for the entire sample. This type of data is necessary in order to use CFD reliably as a design and retrofit tool for co-firing biomass with fossil fuels, as the combustion processes...

Scaling of the burning efficiency for multicomponent fuel pool fires

DEFF Research Database (Denmark)

van Gelderen, Laurens; Farahani, Hamed Farmahini; Rangwala, Ali S.

In order to improve the validity of small scale crude oil burning experiments, which seem to underestimate the burning efficiency obtained in larger scales, the gasification mechanism of crude oil was studied. Gasification models obtained from literature were used to make a set of predictions for...... an external heat source to simulate the larger fire size are currently in process....

MINIMIZATION OF NO EMISSIONS FROM MULTI-BURNER COAL-FIRED BOILERS

Energy Technology Data Exchange (ETDEWEB)

E.G. Eddings; A. Molina; D.W. Pershing; A.F. Sarofim; T.H. Fletcher; H. Zhang; K.A. Davis; M. Denison; H. Shim

2002-01-01

The focus of this program is to provide insight into the formation and minimization of NO{sub x} in multi-burner arrays, such as those that would be found in a typical utility boiler. Most detailed studies are performed in single-burner test facilities, and may not capture significant burner-to-burner interactions that could influence NO{sub x} emissions. Thus, investigations of such interactions were made by performing a combination of single and multiple burner experiments in a pilot-scale coal-fired test facility at the University of Utah, and by the use of computational combustion simulations to evaluate full-scale utility boilers. In addition, fundamental studies on nitrogen release from coal were performed to develop greater understanding of the physical processes that control NO formation in pulverized coal flames--particularly under low NO{sub x} conditions. A CO/H{sub 2}/O{sub 2}/N{sub 2} flame was operated under fuel-rich conditions in a flat flame reactor to provide a high temperature, oxygen-free post-flame environment to study secondary reactions of coal volatiles. Effects of temperature, residence time and coal rank on nitrogen evolution and soot formation were examined. Elemental compositions of the char, tar and soot were determined by elemental analysis, gas species distributions were determined using FTIR, and the chemical structure of the tar and soot was analyzed by solid-state {sup 13}C NMR spectroscopy. A laminar flow drop tube furnace was used to study char nitrogen conversion to NO. The experimental evidence and simulation results indicated that some of the nitrogen present in the char is converted to nitric oxide after direct attack of oxygen on the particle, while another portion of the nitrogen, present in more labile functionalities, is released as HCN and further reacts in the bulk gas. The reaction of HCN with NO in the bulk gas has a strong influence on the overall conversion of char-nitrogen to nitric oxide; therefore, any model that

Physical and combustion characteristics of biomass particles prepared by different milling processes for suspension firing in utility boilers

DEFF Research Database (Denmark)

Yin, Chungen; Momenikouchaksaraei, Maryam; Kær, Søren Knudsen

2016-01-01

close to suspension-fired boilers. The ignition, devolatilization and burnout times of the milled particles under different combustion conditions are analysed. A one-dimensional transient model, properly accounting for the particle-ambient flow interaction and appropriately addressing the key sub...

Modelling and simulating fire tube boiler performance

DEFF Research Database (Denmark)

Sørensen, K.; Condra, T.; Houbak, Niels

2003-01-01

A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

GASIFICATION BASED BIOMASS CO-FIRING - PHASE I

Energy Technology Data Exchange (ETDEWEB)

Babul Patel; Kevin McQuigg; Robert F. Toerne

2001-12-01

Biomass gasification offers a practical way to use this locally available fuel source for co-firing traditional large utility boilers. The gasification process converts biomass into a low Btu producer gas that can be fed directly into the boiler. This strategy of co-firing is compatible with variety of conventional boilers including natural gas fired boilers as well as pulverized coal fired and cyclone boilers. Gasification has the potential to address all problems associated with the other types of co-firing with minimum modifications to the existing boiler systems. Gasification can also utilize biomass sources that have been previously unsuitable due to size or processing requirements, facilitating a reduction in the primary fossil fuel consumption in the boiler and thereby reducing the greenhouse gas emissions to the atmosphere.

Study of flue-gas temperature difference in supercritical once-through boiler

Science.gov (United States)

Kang, Yanchang; Li, Bing; Song, Ang

2018-02-01

The 600 MW coal-fired once-through Boilers with opposed firing at a power plant are found to experience marked temperature variation and even overtemperature on the wall of the heating surface as a result of flue-gas temperature (FGT) variation in the boiler. In this study, operational adjustments were made to the pulverizing, combustion, and secondary air box systems in these boilers, in order to solve problems in internal combustion. The adjustments were found to reduce FGT difference and optimize the boiler’ combustion conditions. The results of this study can provide a reference for optimization of coal-fired boiler of the same type in similar conditions.

Allowing a wildfire to burn: estimating the effect on future fire suppression costs

Science.gov (United States)

Rachel M. Houtman; Claire A. Montgomery; Aaron R. Gagnon; David E. Calkin; Thomas G. Dietterich; Sean McGregor; Mark Crowley

2013-01-01

Where a legacy of aggressive wildland fire suppression has left forests in need of fuel reduction, allowing wildland fire to burn may provide fuel treatment benefits, thereby reducing suppression costs from subsequent fires. The least-cost-plus-net-value-change model of wildland fire economics includes benefits of wildfire in a framework for evaluating suppression...

Evaluation of Gas Reburning and Low N0x Burners on a Wall Fired Boiler

Energy Technology Data Exchange (ETDEWEB)

None

1998-07-01

Under the U.S. Department of Energy's Clean Coal Technology Program (Round 3), a project was completed to demonstrate control of boiler NOX emissions and to a lesser degree, due to coal replacement, SO2 emissions. The project involved combining Gas Reburning with Low NOX Burners (GR-LNB) on a coal-fired electric utility boiler to determine if high levels of NO, reduction (70VO) could be achieved. Sponsors of the project included the U.S. Depatiment of Energy, the Gas Research Institute, Public Service Company of Colorado, Colorado Interstate Gas, Electric Power Research Institute, and the Energy and Environmental Research Corporation. The GR-LNB demonstration was petformed on Public Service Company of Colorado's (PSCO) Cherokee Unit #3, located in Denver, Colorado. This unit is a 172 MW~ wall-fired boiler that uses Colorado bituminous, low-sulfur coal. It had a baseline NO, emission level of 0.73 lb/1 OG Btu using conventional burners. Low NOX burners are designed to yield lower NOX emissions than conventional burners. However, the NOX control achieved with this technique is limited to 30-50Y0. Also, with LNBs, CO emissions can increase to above acceptable standards. Gas Reburning (GR) is designed to reduce NO, in the flue gas by staged fuel combustion. This technology involves the introduction of' natural gas into the hot furnace flue gas stream. When combined, GR and LNBs minimize NOX emissions and maintain acceptable levels of CO emissions. A comprehensive test program was completed, operating over a wide range of boiler conditions. Over 4,000 hours of operation were achieved, providing substantial data. Measurements were taken to quantify reductions in NOX emissions, the impact on boiler equipment and operability and factors influencing costs. The GR-LNB technology achieved good NO, emission reductions and the goals of the project were achieved. Although the performance of the low NOX burners (supplied by others) was less than expected, a NOX

Metallurgical Analysis of Cracks Formed on Coal Fired Boiler Tube

Science.gov (United States)

Kishor, Rajat; Kyada, Tushal; Goyal, Rajesh K.; Kathayat, T. S.

2015-02-01

Metallurgical failure analysis was carried out for cracks observed on the outer surface of a boiler tube made of ASME SA 210 GR A1 grade steel. The cracks on the surface of the tube were observed after 6 months from the installation in service. A careful visual inspection, chemical analysis, hardness measurement, detailed microstructural analysis using optical and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy were carried out to ascertain the cause for failure. Visual inspection of the failed tube revealed the presence of oxide scales and ash deposits on the surface of the tube exposed to fire. Many cracks extending longitudinally were observed on the surface of the tube. Bulging of the tube was also observed. The results of chemical analysis, hardness values and optical micrographs did not exhibit any abnormality at the region of failure. However, detailed SEM with EDS analysis confirmed the presence of various oxide scales. These scales initiated corrosion at both the inner and outer surfaces of the tube. In addition, excessive hoop stress also developed at the region of failure. It is concluded that the failure of the boiler tube took place owing to the combined effect of the corrosion caused by the oxide scales as well as the excessive hoop stress.

Burning issues

Energy Technology Data Exchange (ETDEWEB)

Ashmore, C.

1998-10-01

Coal is world`s most abundant source of energy. Turning this potential pollutant into a clean, cost-effective fuel for power production has become a matter for global concern. Some problems and their solutions are highlighted in this article. Environmental problems caused by the giant Mae Moh plant in Thailand were overcome with an extensive retrofit programme that included flue gas desulfurisation systems. For new and smaller coal-fuelled plant, boilers using circulating fluidised bed (CFB) technology provide a cost effective and efficient system which meets environmental standards. A large independent power plant at Colver, Pennsylvania, USA uses CFB technology to burn bituminous gob. AMM and Alstom can provide turnkey packages for coal-fired power plant using a modular concept based on CFB technology. 2 photos.

A method for mapping the motion and temperature history of fuel particles in grate boilers and waste incinerators - stage 1; Metod foer kartlaeggning av braenslepartiklars roerelse och temperaturhistorik i rosterpannor/avfallsugnar - etapp 1

Energy Technology Data Exchange (ETDEWEB)

Gustavsson, Lennart; Blom, Elisabeth; Hald Pedersen, Niels; Moritz, Anders; Maardsjoe, Olle; Oskarsson, Jan; Petersson, Mats

2000-04-01

A feasibility study has been conducted where methods using radioactive tracer techniques for studying the behaviour of fuel particles on a grate are proposed and assessed. The following topics are addressed: - the possibility to continuously register the position of a single fuel particle on a grate from the fuel feed to burn-out; - the possibility to determine when a single fuel particle reach a certain temperature; and - the possibility to study drying and pyrolysis processes for a single fuel particle. In addition, a method to determine the height and density profiles of a fuel bed on a grate is proposed. The method for continuous determination of position is based on including a radiation source of the isotope {sup 24}Na in a fuel particle which is then supplied to the fuel feed. The gamma radiation emitted is registered by a number of detectors, mounted on the outside of the boiler. Since the radiation registered is dependent on both the distance between the source and detector and on the materials in the pathway, it is possible to continuously calculate the position of the fuel particle with the aid of Monte Carlo simulation. The inaccuracy in the determination is estimated to less than 5 cm. This is deemed to be accurate enough to be interesting. In order to study when a fuel particle reach a certain temperature, it is proposed that vials, manufactured in materials that will be broken at a defined temperature, is filled with the isotope {sup 85}Kr and mounted in fuel particles. When this noble gas is released, it follows the flue gases through the boiler and can be detected in the flue gas duct through its beta emission. The drying process of a fuel particle is proposed to be studied through impregnating fuel particles with tritium-containing water. The tritium-containing water is evaporated as the fuel particle dries and through analysing the tritium content of the flue gases the drying process can be followed. The feasibility study also deals with the

Burn Severity and Its Impact on Soil Properties: 2016 Erskine Fire in the Southern Sierra Nevada

Science.gov (United States)

Haake, S.; Guo, J.; Krugh, W. C.

2017-12-01

Wildfire frequency in the southern Sierra Nevada has increased over the past decades. The effects of wildfires on soils can increase the frequency of slope failure and debris flow events, which pose a greater risk to people, as human populations expand into foothill and mountainous communities of the Sierra Nevada. Alterations in the physical properties of burned soils are one such effect that can catalyze slope failure and debris flow events. Moreover, the degree of a soil's physical alteration resulting from wildfire is linked to fire intensity. The 2016 Erskine fire occurred in the southern Sierra Nevada, burning 48,019 acres, resulting in soils of unburned, low, moderate, and high burn severities. In this study, the physical properties of soils with varying degrees of burn severity are explored within the 2016 Erskine fire perimeter. The results constrain the effects of burn severity on soil's physical properties. Unburned, low, moderate, and high burn severity soil samples were collected within the Erskine fire perimeter. Alterations in soils' physical properties resulting from burn severity are explored using X-ray diffractometry analysis, liquid limit, plastic limit, and shear strength tests. Preliminary results from this study will be used to assess debris flow and slope failure hazard models within burned areas of the Kern River watershed in the southern Sierra Nevada.

Deposit Formation in a 150 MWe Utility PF-Boiler during Co-combustion of Coal and Straw

DEFF Research Database (Denmark)

Andersen, Karin Hedebo; Frandsen, Flemming; Hansen, P. F. B.

2000-01-01

A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part of the demon......A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part...... problematic deposits. Go-firing straw also caused a change in the structure of the upstream deposits. During coal combustion an ordered, "finger" structure of the larger particles with small particles between was observed, whereas during co-combustion a more random deposition of the larger particles among...... arise when burning other coals, particularly coals with a high S or alkali metal content or a low content of ash. The behavior of K, Ca, S, and Cl was evaluated by use of thermodynamic calculations. The thermodynamically stable species agree with the observed behavior in the experiments, i.e. formation...

Failure analysis of boiler tube

International Nuclear Information System (INIS)

Mehmood, K.; Siddiqui, A.R.

2007-01-01

Boiler tubes are energy conversion components where heat energy is used to convert water into high pressure superheated steam, which is then delivered to a turbine for electric power generation in thermal power plants or to run plant and machineries in a process or manufacturing industry. It was reported that one of the tubes of a fire-tube boiler used in a local industry had leakage after the formation of pits at the external surface of the tube. The inner side of the fire tube was working with hot flue gasses with a pressure of 10 Kg/cm/sup 2/ and temperature 225 degree C. The outside of the tube was surrounded by feed water. The purpose of this study was to determine the cause of pits developed at the external surface of the failed boiler tube sample. In the present work boiler tube samples of steel grade ASTM AI61/ASTM A192 were analyzed using metallographic analysis, chemical analysis, and mechanical testing. It was concluded that the appearance of defects on the boiler tube sample indicates cavitation type corrosion failure. Cavitation damage superficially resembled pitting, but surface appeared considerably rougher and had many closely spaced pits. (author)

Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications. Task 4 - Testing in Alstom's 15 MW_th Boiler Simulation Facility

Energy Technology Data Exchange (ETDEWEB)

Levasseur, Armand

2014-04-30

Alstom Power Inc. (Alstom), under U.S. DOE/NETL Cooperative Agreement No. DE-NT0005290, is conducting a development program to generate detailed technical information needed for application of oxy-combustion technology. The program is designed to provide the necessary information and understanding for the next step of large-scale commercial demonstration of oxy combustion in tangentially fired boilers and to accelerate the commercialization of this technology. The main project objectives include: Design and develop an innovative oxyfuel system for existing tangentially-fired boiler units that minimizes overall capital investment and operating costs; Evaluate performance of oxyfuel tangentially fired boiler systems in pilot scale tests at Alstom’s 15 MWth tangentially fired Boiler Simulation Facility (BSF); Address technical gaps for the design of oxyfuel commercial utility boilers by focused testing and improvement of engineering and simulation tools; Develop the design, performance and costs for a demonstration scale oxyfuel boiler and auxiliary systems; Develop the design and costs for both industrial and utility commercial scale reference oxyfuel boilers and auxiliary systems that are optimized for overall plant performance and cost; and, Define key design considerations and develop general guidelines for application of results to utility and different industrial applications. The project was initiated in October 2008 and the scope extended in 2010 under an ARRA award. The project is scheduled for completion by April 30, 2014. Central to the project is 15 MWth testing in the BSF, which provided in-depth understanding of oxy-combustion under boiler conditions, detailed data for improvement of design tools, and key information for application to commercial scale oxy-fired boiler design. Eight comprehensive 15 MWth oxy-fired test campaigns were performed with different coals, providing detailed data on combustion, emissions, and thermal behavior over a matrix of

Spatial and temporal corroboration of a fire-scar-based fire history in a frequently burned ponderosa pine forest.

Science.gov (United States)

Farris, Calvin A; Baisan, Christopher H; Falk, Donald A; Yool, Stephen R; Swetnam, Thomas W

2010-09-01

Fire scars are used widely to reconstruct historical fire regime parameters in forests around the world. Because fire scars provide incomplete records of past fire occurrence at discrete points in space, inferences must be made to reconstruct fire frequency and extent across landscapes using spatial networks of fire-scar samples. Assessing the relative accuracy of fire-scar fire history reconstructions has been hampered due to a lack of empirical comparisons with independent fire history data sources. We carried out such a comparison in a 2780-ha ponderosa pine forest on Mica Mountain in southern Arizona (USA) for the time period 1937-2000. Using documentary records of fire perimeter maps and ignition locations, we compared reconstructions of key spatial and temporal fire regime parameters developed from documentary fire maps and independently collected fire-scar data (n = 60 plots). We found that fire-scar data provided spatially representative and complete inventories of all major fire years (> 100 ha) in the study area but failed to detect most small fires. There was a strong linear relationship between the percentage of samples recording fire scars in a given year (i.e., fire-scar synchrony) and total area burned for that year (y = 0.0003x + 0.0087, r2 = 0.96). There was also strong spatial coherence between cumulative fire frequency maps interpolated from fire-scar data and ground-mapped fire perimeters. Widely reported fire frequency summary statistics varied little between fire history data sets: fire-scar natural fire rotations (NFR) differed by or = 25% of study area burned) were identical between data sets (25.5 yr); fire-scar MFIs for all fire years differed by 1.2 yr from documentary records. The known seasonal timing of past fires based on documentary records was furthermore reconstructed accurately by observing intra-annual ring position of fire scars and using knowledge of tree-ring growth phenology in the Southwest. Our results demonstrate clearly

"Fire Moss" Cover and Function in Severely Burned Forests of the Western United States

Science.gov (United States)

Grover, H.; Doherty, K.; Sieg, C.; Robichaud, P. R.; Fulé, P. Z.; Bowker, M.

2017-12-01

With wildfires increasing in severity and extent throughout the Western United States, land managers need new tools to stabilize recently burned ecosystems. "Fire moss" consists of three species, Ceratodon purpureus, Funaria hygrometrica, and Bryum argentum. These mosses colonize burned landscapes quickly, aggregate soils, have extremely high water holding capacity, and can be grown rapidly ex-situ. In this talk, I will focus on our efforts to understand how Fire Moss naturally interacts with severely burned landscapes. We examined 14 fires in Arizona, New Mexico, Washington, and Idaho selecting a range of times since fire, and stratified plots within each wildfire by winter insolation and elevation. At 75+ plots we measured understory plant cover, ground cover, Fire Moss cover, and Fire Moss reproductive effort. On plots in the Southwest, we measured a suite of soil characteristics on moss covered and adjacent bare soil including aggregate stability, shear strength, compressional strength, and infiltration rates. Moss cover ranged from 0-75% with a mean of 16% across all plots and was inversely related to insolation (R2 = .32, p = stability and infiltration rates as adjacent bare ground. These results will allow us to model locations where Fire Moss will naturally increase postfire hillslope soil stability, locations for targeting moss restoration efforts, and suggest that Fire Moss could be a valuable tool to mitigate post wildfire erosion.

CFD modeling of small biomass-fired boilers, second stage; CFD-modellering av mindre biobraenslepannor, etapp 2

Energy Technology Data Exchange (ETDEWEB)

Loennermark, A. [Swedish National Testing and Research Inst., Boraas (Sweden); Leckner, B. [Chalmers Univ. of Techn., Goeteborg (Sweden). Dept. of Energy Technology

2001-11-01

The purpose of the project is to study how the design of the gas combustion chamber in a small boiler for biomass affects the emissions and how computer simulations can be used to decrease harmful emissions. The aim of the first part of the project was to investigate how phenomena and processes, important for the combustion, depend on various parameters. Within the frame of that part the temperature distribution, the flow pattern and the mixing processes have been studied. In the second part the combustion and the different reactions have been studied. A number of well-equipped combustion experiments in a small biomass-fired boiler have also been conducted to obtain better information about the boundary conditions. The results have been used to verify the simulations. The gas combustion chamber of a modern boiler using down draught firing has been simulated by using two Computational Fluid Dynamics codes, SOFIE and FLUENT. The results from the simulations show that with literature values for the reaction parameters, the reaction rates are controlled by mixing. This means that the reactions are fast and all the CO and the hydrocarbons were consumed. By varying the activation energy, it is possible to reach data that are more comparable with experimental data. The effects of the bowl in the gas combustion chamber on the combustion and mixing are discussed. The effects of the temperature and the radiation are also presented.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

Science.gov (United States)

Knapp, E.E.; Keeley, J.E.

2006-01-01

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

Is proportion burned severely related to daily area burned?

International Nuclear Information System (INIS)

Birch, Donovan S; Morgan, Penelope; Smith, Alistair M S; Kolden, Crystal A; Hudak, Andrew T

2014-01-01

The ecological effects of forest fires burning with high severity are long-lived and have the greatest impact on vegetation successional trajectories, as compared to low-to-moderate severity fires. The primary drivers of high severity fire are unclear, but it has been hypothesized that wind-driven, large fire-growth days play a significant role, particularly on large fires in forested ecosystems. Here, we examined the relative proportion of classified burn severity for individual daily areas burned that occurred during 42 large forest fires in central Idaho and western Montana from 2005 to 2007 and 2011. Using infrared perimeter data for wildfires with five or more consecutive days of mapped perimeters, we delineated 2697 individual daily areas burned from which we calculated the proportions of each of three burn severity classes (high, moderate, and low) using the differenced normalized burn ratio as mapped for large fires by the Monitoring Trends in Burn Severity project. We found that the proportion of high burn severity was weakly correlated (Kendall τ = 0.299) with size of daily area burned (DAB). Burn severity was highly variable, even for the largest (95th percentile) in DAB, suggesting that other variables than fire extent influence the ecological effects of fires. We suggest that these results do not support the prioritization of large runs during fire rehabilitation efforts, since the underlying assumption in this prioritization is a positive relationship between severity and area burned in a day. (letters)

BEHAVE: fire behavior prediction and fuel modeling system-BURN Subsystem, part 1

Science.gov (United States)

Patricia L. Andrews

1986-01-01

Describes BURN Subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.

Economic evaluation of a coal fired boiler

International Nuclear Information System (INIS)

Briem, J.J.

1983-01-01

This paper provides basic information on boiler economics which will assist steam users in analyzing the feasibility of using coal to generate steam - in either new or existing facilities. The information presented covers boilers ranging in size from 10,000 to 100,000 pounds per hour steaming capacity

DEVELOPMENT AND TESTING OF COMPOUND FUEL CHAMBER WITHOUT A GRATE FOR HOUSEHOLD FURNACE

Directory of Open Access Journals (Sweden)

Shevyakov Vladimir Viktorovich

2018-02-01

Full Text Available In hearth furnaces, the firewood is burned more cleanly with less carbon monoxide at the outlet. The disadvantage of such fireboxes is a longer process of coal burnout than in grate-fired furnaces. In furnaces with a grate, the burnout time of coals is less, which makes it possible to finish the combustion process more quickly and close the outlet latch. This increases the efficiency of the furnace but to further reduce the time of burning out the coals they have to be raked and burned on the grate. This complicates the process of operating the furnace itself. The proposed design of the compound firebox allows us to improve characteristics of both the firebox itself and the entire furnace. Research objectives: creation and study of a compound firebox that increases the efficiency of the furnace and simplifies the furnace maintenance process with the values of carbon monoxide at the outlet comparable to hearth furnaces. Materials and methods: a detailed analysis of hearth fuel chambers ECO+ was carried out according to the amount of carbon monoxide at the outlet. The results of the analysis are used for comparison with compound fuel chamber. The structure of the compound firebox was chosen based on the results of preliminary tests of several fuel chambers proposed and tested by the author in the furnace PDKSh-2.0. A peculiarity of the structure of the compound firebox is the absence of a grate and the presence of a narrow slit in the lower part of the firebox through which the incoming air enters the firewood. Between the walls of the firebox and firewood, skids are installed, forming an air gap, through which the inlet air is uniformly supplied to the entire firewood supply. With gradual combustion of firewood and formation of coal, the firewood descends to the bottom of the firebox, where they intensively burn out in the maximum air flow. Compound firebox consists of several parts, it is made of steel with a thickness of 4.0 mm and installed

ULTRA LOW NOx INTEGRATED SYSTEM FOR NOx EMISSION CONTROL FROM COAL-FIRED BOILERS

Energy Technology Data Exchange (ETDEWEB)

Galen H. Richards; Charles Q. Maney; Richard W. Borio; Robert D. Lewis

2002-12-30

ALSTOM Power Inc.'s Power Plant Laboratories, working in concert with ALSTOM Power's Performance Projects Group, has teamed with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient NOx control technologies for retrofit to pulverized coal fired utility boilers. The objective of this project was to develop retrofit NOx control technology to achieve less than 0.15 lb/MMBtu NOx (for bituminous coals) and 0.10 lb/MMBtu NOx (for subbituminous coals) from existing pulverized coal fired utility boilers at a cost which is at least 25% less than SCR technology. Efficient control of NOx is seen as an important, enabling step in keeping coal as a viable part of the national energy mix in this century, and beyond. Presently 57% of U.S. electrical generation is coal based, and the Energy Information Agency projects that coal will maintain a lead in U.S. power generation over all other fuel sources for decades (EIA 1998 Energy Forecast). Yet, coal-based power is being strongly challenged by society's ever-increasing desire for an improved environment and the resultant improvement in health and safety. The needs of the electric-utility industry are to improve environmental performance, while simultaneously improving overall plant economics. This means that emissions control technology is needed with very low capital and operating costs. This project has responded to the industry's need for low NOx emissions by evaluating ideas that can be adapted to present pulverized coal fired systems, be they conventional or low NOx firing systems. The TFS 2000{trademark} firing system has been the ALSTOM Power Inc. commercial offering producing the lowest NOx emission levels. In this project, the TFS 2000{trademark} firing system served as a basis for comparison to other low NOx systems evaluated and was the foundation upon which refinements were made to further

Staged fluidized-bed coal combustor for boiler retrofit

International Nuclear Information System (INIS)

Rehmat, A.; Dorfman, L.; Shibayama, G.; Waibel, R.

1991-01-01

The Advanced Staged Fluidized-Bed Coal Combustion System (ASC) is a novel clean coal technology for either coal-fired repowering of existing boilers or for incremental power generation using combined-cycle gas turbines. This new technology combines staged combustion for gaseous emission control, in-situ sulfur capture, and an ash agglomeration/vitrification process for the agglomeration/vitrification of ash and spent sorbent, thus rendering solid waste environmentally benign. The market for ASC is expected to be for clean coal-fired repowering of generating units up to 250 MW, especially for units where space is limited. The expected tightening of the environmental requirements on leachable solids residue by-products could considerably increase the marketability for ASC. ASC consists of modular low-pressure vessels in which coal is partially combusted and gasified using stacked fluidized-bed processes to produce low-to-medium-Btu, high-temperature gas. This relatively clean fuel gas is used to repower/refuel existing pulverized-coal, natural gas, or oil-fired boilers using bottom firing and reburning techniques. The benefits of ASC coal-fired repowering include the ability to repower boilers without obtaining additional space while meeting the more stringent environmental requirements of the future. Low NO x , SO x , and particulate levels are expected while a nonleachable solid residue with trace metal encapsulation is produced. ASC also minimizes boiler modification and life-extension expenditures. Repowered efficiencies can be restored to the initial operating plant efficiency, and the existing boiler capacity can be increased by 10%. Preliminary cost estimates indicate that ASC will have up to a $250/kW capital cost advantage over existing coal-fired repowering options. 4 figs., 4 tabs

Investigations of combustion process in combined cooker-boiler fired on solid fuels

Directory of Open Access Journals (Sweden)

Stojiljković Dragoslava D.

2006-01-01

Full Text Available The aim of the investigation was to make some reconstructions on the existing stove used for cooking and baking and to obtain the combined cooker-boiler which will fulfill the demands of European standard EN 12815. Implementation of modern scientific achievements in the field of combustion on stoves and furnaces fired on solid fuels was used. During the investigations four various constructions were made with different fresh air inlet and secondary air supply with the intention to obtain more complete combustion with increased efficiency and reduced CO emission. Three different fuels were used: firewood, coal, and wood briquette. A numerous parameters were measured: fuel weight changes during the combustion process, temperature of inlet and outlet water, flue gas composition (O2, CO, SO2, CO2, NOx, flue gas temperature, ash quantity etc. The result of the investigations is the stove with the efficiency of more than 75% - boiler Class 1 (according EN 12815 and CO emission of about 1% v/v. The results obtained during the measurements were used as parameters for modeling of combustion process. .

Probabilistic approach to determining the optimum replacement of a superheater stage in 680 MW coal-fired boiler

Energy Technology Data Exchange (ETDEWEB)

Bos, Robert; Star, Ruud van der [Nuon Power Generation, Amsterdam (Netherlands)

2009-07-01

The boiler of the NUON power plant HW08 that went into operation in 1993 is designed as Benson boiler and mainly fired with hard coal. A creep-related tube failure occurred in the tertiary superheater that had been due to increased wall temperature caused by steam side formation of oxide layers. The theoretical lifetime of the components was calculated with the aid of the results of steam side oxide measurements and condition evaluation of the tertiary superheater with the aid of tube samples. The objective is to establish an operation and maintenance schedule for the desired operating lifetime of 300,000 hours. (orig.)

Straw combustion on slow-moving grates

DEFF Research Database (Denmark)

Kær, Søren Knudsen

2005-01-01

Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ‘‘walking......-column’’ approach and includes the energy equations for both the fuel and the gas accounting for heat transfer between the two phases. The model gives important insight into the combustion process and provides inlet conditions for a computational fluid dynamics analysis of the freeboard. The model predictions...... indicate the existence of two distinct combustion modes. Combustion air temperature and mass flow-rate are the two parameters determining the mode. There is a significant difference in reaction rates (ignition velocity) and temperature levels between the two modes. Model predictions were compared...

The influence of weather and fuel type on the fuel composition of the area burned by forest fires in Ontario, 1996-2006.

Science.gov (United States)

Podur, Justin J; Martell, David L

2009-07-01

Forest fires are influenced by weather, fuels, and topography, but the relative influence of these factors may vary in different forest types. Compositional analysis can be used to assess the relative importance of fuels and weather in the boreal forest. Do forest or wild land fires burn more flammable fuels preferentially or, because most large fires burn in extreme weather conditions, do fires burn fuels in the proportions they are available despite differences in flammability? In the Canadian boreal forest, aspen (Populus tremuloides) has been found to burn in less than the proportion in which it is available. We used the province of Ontario's Provincial Fuels Database and fire records provided by the Ontario Ministry of Natural Resources to compare the fuel composition of area burned by 594 large (>40 ha) fires that occurred in Ontario's boreal forest region, a study area some 430,000 km2 in size, between 1996 and 2006 with the fuel composition of the neighborhoods around the fires. We found that, over the range of fire weather conditions in which large fires burned and in a study area with 8% aspen, fires burn fuels in the proportions that they are available, results which are consistent with the dominance of weather in controlling large fires.

Experiment research of slag renovation in the corner-fired boiler

Energy Technology Data Exchange (ETDEWEB)

Gong, Zhijun; Wu, Wenfei [Inner Mongolia Univ. of Science and Technology, Baotou (China). School of Energy and Environment

2013-07-01

Aiming at serious slag on the water wall around the burner of corner-fired boiler with low-ash-fusion-point coal, cold experimental model has been established. In this experiment, particle image velocimetry (PIV) has been employed to accurately measure aerodynamic field of burner region, and the experimental research of furnace slag renovation has been conducted through changing the burner jet arrangement. The experiment results show that it has significantly effect on aerodynamic field in the furnace by changing burner jet deflection angle. A reasonable actual tangential circle diameter can be formed through adjusting the burner jet deflection angle, to prevent primary air attacking the wall, and further more, to effectively prevent serious slag on the water wall around the burner.

GASIFICATION BASED BIOMASS CO-FIRING - PHASE I; SEMIANNUAL

International Nuclear Information System (INIS)

Babul Patel; Kevin McQuigg; Robert F. Toerne

2001-01-01

Biomass gasification offers a practical way to use this locally available fuel source for co-firing traditional large utility boilers. The gasification process converts biomass into a low Btu producer gas that can be fed directly into the boiler. This strategy of co-firing is compatible with variety of conventional boilers including natural gas fired boilers as well as pulverized coal fired and cyclone boilers. Gasification has the potential to address all problems associated with the other types of co-firing with minimum modifications to the existing boiler systems. Gasification can also utilize biomass sources that have been previously unsuitable due to size or processing requirements, facilitating a reduction in the primary fossil fuel consumption in the boiler and thereby reducing the greenhouse gas emissions to the atmosphere

Investigation for the sodium leak in Monju. Sodium leak and fire test-1

International Nuclear Information System (INIS)

Kawata, Koji; Ohno, Shuji; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi

2000-08-01

As a part of the work for investigating the sodium leak accident which occurred in the Monju reactor (hereinafter referred to as Monju) on December 8, 1995, three tests, (1) a sodium leak test, (2) a sodium leak and fire test-1, and (3) a sodium leak and fire test-II, were carried out at OEC/PEC. The main objectives of these tests were to confirm the leak and burning behavior of sodium from the damaged thermometer, and the effects of the sodium fire on the integrity of the surrounding structure. This report describes the results of the sodium fire test-I carried out as a preliminary test. The test was performed using the SOLFA-2 (Sodium Leak, Fire and Aerosol) facility on April 8, 1996. In this test, sodium heated to 480degC was leaked for approximately 1.5 hours from a leak simulating apparatus and caused to drop onto a ventilation duct and a grating with the same dimensions and layout as those in Monju. The main conclusions obtained from the test are shown below: 1) Observation from video cameras in the test revealed that in the early stages of the sodium leak, sodium dripped out of the flexible tube of the thermometer. This dripping and burning expanded in range as the sodium splashed on the duct. 2) No damage to the duct itself was detected. However, the aluminum louver frame of the ventilation duct's lower inlet was damaged. Its machine screws came off, leaving half of the grill (on the grating side) detached. 3) No large hole, like the one seen at Monju, was found when the grating was removed from the testing system for inspection, although the area centered on the point were the sodium dripped was damaged in a way indicating the first stages of grating failure. The 5mm square lattice was corroded through in some parts, and numerous blades (originally 3.2 mm thick) had become sharpened like the blade of a knife. 4) The burning pan underside thermocouple near the leak point measured 700degC in within approximately 10 minutes, and for the next hour remained

Coal utilization in industrial boilers in China - a prospect for mitigating CO2 emissions

International Nuclear Information System (INIS)

Fang, J.; Zeng, T.; Yang, L.I.S.; Oye, K.A.; Sarofim, A.F.; Beer, J.M.

1999-01-01

It is estimated from GEF statistical data for 1991 that more than 500,000 industrial boilers (mostly stoker-fired) in China consume over 400 million tons of coal per year. Each year, because of low boiler efficiency, 75 million tons of coal is wasted and 130 million tons of excess CO 2 are emitted. An analysis of 250 boiler thermal-balance test certificates and 6 field visits in three provinces have shown that: (1) boilers with efficiencies of less than 70% account for 75% of the total boiler-population; (2) the main causes of the low efficiencies are high excess air and unburned carbon in the slag and fly ash. The effect of unburned carbon on CO 2 emission is a balance of positive and negative contributions: while the unburned carbon does not produce CO 2 emissions, its replacement carbon, burned at a low efficiency, contributes to a net increase in CO 2 emissions. It seems from the analysis that the average boiler efficiency can be raised to 73% by relatively simple means, such as the size grading of the coal, improved boiler operating practice and some inexpensive equipment modifications. This could then result in savings each year of 34 million tons of coal and a reduction in CO 2 emissions of 63 million tons at an estimated cost of $10 per ton of CO 2 . (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Burn and they will come! The western regional birds and burns study examines bird responses to prescribed fire

Science.gov (United States)

Jonathan Thompson; John Lehmkuhl

2008-01-01

Although prescribed fire is increasingly being used in ponderosa pine forests as a management tool to reduce the risk of future high-severity wildfire, its effects on wildlife habitat have rarely been examined. The Birds and Burns Network was created to assist managers in planning prescribed fire projects that will reduce fuels and enhance bird habitat. Researchers...

Recovery Act: Oxy-Combustion Techology Development for Industrial-Scale Boiler Applications

Energy Technology Data Exchange (ETDEWEB)

Levasseur, Armand

2014-04-30

Alstom Power Inc. (Alstom), under U.S. DOE/NETL Cooperative Agreement No. DE-NT0005290, is conducting a development program to generate detailed technical information needed for application of oxy-combustion technology. The program is designed to provide the necessary information and understanding for the next step of large-scale commercial demonstration of oxy combustion in tangentially fired boilers and to accelerate the commercialization of this technology. The main project objectives include: • Design and develop an innovative oxyfuel system for existing tangentially-fired boiler units that minimizes overall capital investment and operating costs. • Evaluate performance of oxyfuel tangentially fired boiler systems in pilot scale tests at Alstom’s 15 MWth tangentially fired Boiler Simulation Facility (BSF). • Address technical gaps for the design of oxyfuel commercial utility boilers by focused testing and improvement of engineering and simulation tools. • Develop the design, performance and costs for a demonstration scale oxyfuel boiler and auxiliary systems. • Develop the design and costs for both industrial and utility commercial scale reference oxyfuel boilers and auxiliary systems that are optimized for overall plant performance and cost. • Define key design considerations and develop general guidelines for application of results to utility and different industrial applications. The project was initiated in October 2008 and the scope extended in 2010 under an ARRA award. The project completion date was April 30, 2014. Central to the project is 15 MWth testing in the BSF, which provided in-depth understanding of oxy-combustion under boiler conditions, detailed data for improvement of design tools, and key information for application to commercial scale oxy-fired boiler design. Eight comprehensive 15 MWth oxy-fired test campaigns were performed with different coals, providing detailed data on combustion, emissions, and thermal behavior over a

Electron beam technology for multipollutant emissions control from heavy fuel oil-fired boiler.

Science.gov (United States)

Chmielewski, Andrzej G; Ostapczuk, Anna; Licki, Janusz

2010-08-01

The electron beam treatment technology for purification of exhaust gases from the burning of heavy fuel oil (HFO) mazout with sulfur content approximately 3 wt % was tested at the Institute of Nuclear Chemistry and Technology laboratory plant. The parametric study was conducted to determine the sulfur dioxide (SO2), oxides of nitrogen (NO(x)), and polycyclic aromatic hydrocarbon (PAH) removal efficiency as a function of temperature and humidity of irradiated gases, absorbed irradiation dose, and ammonia stoichiometry process parameters. In the test performed under optimal conditions with an irradiation dose of 12.4 kGy, simultaneous removal efficiencies of approximately 98% for SO2, and 80% for NO(x) were recorded. The simultaneous decrease of PAH and one-ringed aromatic hydrocarbon (benzene, toluene, and xylenes [BTX]) concentrations was observed in the irradiated flue gas. Overall removal efficiencies of approximately 42% for PAHs and 86% for BTXs were achieved with an irradiation dose 5.3 kGy. The decomposition ratio of these compounds increased with an increase of absorbed dose. The decrease of PAH and BTX concentrations was followed by the increase of oxygen-containing aromatic hydrocarbon concentrations. The PAH and BTX decomposition process was initialized through the reaction with hydroxyl radicals that formed in the electron beam irradiated flue gas. Their decomposition process is based on similar principles as the primary reaction concerning SO2 and NO(x) removal; that is, free radicals attack organic compound chains or rings, causing volatile organic compound decomposition. Thus, the electron beam flue gas treatment (EBFGT) technology ensures simultaneous removal of acid (SO2 and NO(x)) and organic (PAH and BTX) pollutants from flue gas emitted from burning of HFO. This technology is a multipollutant emission control technology that can be applied for treatment of flue gas emitted from coal-, lignite-, and HFO-fired boilers. Other thermal processes such

Understory response to varying fire frequencies after 20 years of prescribed burning in an upland oak forest

Science.gov (United States)

Burton, J.A.; Hallgren, S.W.; Fuhlendorf, S.D.; Leslie, David M.

2011-01-01

Ecosystems in the eastern United States that were shaped by fire over thousands of years of anthropogenic burning recently have been subjected to fire suppression resulting in significant changes in vegetation composition and structure and encroachment by invasive species. Renewed interest in use of fire to manage such ecosystems will require knowledge of effects of fire regime on vegetation. We studied the effects of one aspect of the fire regime, fire frequency, on biomass, cover and diversity of understory vegetation in upland oak forests prescribe-burned for 20 years at different frequencies ranging from zero to five fires per decade. Overstory canopy closure ranged from 88 to 96% and was not affected by fire frequency indicating high tolerance of large trees for even the most frequent burning. Understory species richness and cover was dominated by woody reproduction followed in descending order by forbs, C3 graminoids, C4 grasses, and legumes. Woody plant understory cover did not change with fire frequency and increased 30% from one to three years after a burn. Both forbs and C3 graminoids showed a linear increase in species richness and cover as fire frequency increased. In contrast, C4 grasses and legumes did not show a response to fire frequency. The reduction of litter by fire may have encouraged regeneration of herbaceous plants and helped explain the positive response of forbs and C3 graminoids to increasing fire frequency. Our results showed that herbaceous biomass, cover, and diversity can be managed with long-term prescribed fire under the closed canopy of upland oak forests. ?? 2011 Springer Science+Business Media B.V.

High Temperature Behavior of Cr3C2-NiCr Coatings in the Actual Coal-Fired Boiler Environment

Science.gov (United States)

Bhatia, Rakesh; Sidhu, Hazoor Singh; Sidhu, Buta Singh

2015-03-01

Erosion-corrosion is a serious problem observed in steam-powered electricity generation plants, and industrial waste incinerators. In the present study, four compositions of Cr3C2-(Ni-20Cr) alloy coating powder were deposited by high-velocity oxy-fuel spray technique on T-91 boiler tube steel. The cyclic studies were performed in a coal-fired boiler at 1123 K ± 10 K (850 °C ± 10 °C). X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis and elemental mapping analysis techniques were used to analyze the corrosion products. All the coatings deposited on T-91 boiler tube steel imparted hot corrosion resistance. The 65 pctCr3C2 -35 pct (Ni-20Cr)-coated T-91 steel sample performed better than all other coated samples in the given environment.

Exploration of burning plasmas in FIRE

International Nuclear Information System (INIS)

Meade, D.M.; Kessel, C.E.; Hammett, G.W.

2003-01-01

The Advanced Reactor Innovation Evaluation Studies (ARIES) have identified the key physics and technical issues that must be resolved before attractive fusion reactors can be designed and built. The Fusion Ignition Research Experiment (FIRE) design study has been undertaken to define the lowest cost facility to address the key burning plasma and advanced tokamak physics issues identified in the ARIES studies. The configuration chosen for FIRE is similar to that of ARIES-AT, a steady-state advanced tokamak reactor based on a high-βand high-bootstrap-current operating regime. The key advanced tokamak features of FIRE are: strong plasma shaping, double-null pumping divertors, low toroidal field ripple ( cr ). A longer term goal of FIRE is to explore 'steady-state' high-β advanced tokamak regimes with high bootstrap fractions (f BS ) ∼ 75% at β N ∼ 4 and moderate fusion gain (Q ∼ 5 to 10) under quasi-steady-state conditions for ∼ 3 τ cr . FIRE activities have focused on the physics and engineering assessment of a compact, high-field, cryogenic-copper-coil tokamak with: R o = 2.14 m, a = 0.595 m, B t (R o ) = 6 to 10T, I p = 4.5 to 7.7 MA with a flat top time of 40 to 20 s for 150 MW of fusion power. FIRE will utilize only metal plasma facing components; Be coated tiles for the first wall and W brush divertors to reduce tritium retention as required for fusion reactors. FIRE will be able to test divertor and plasma facing components under reactor relevant power densities since the fusion power density of 6 MWm -3 and neutron wall loading of 2.3 MWm -2 approach those expected in a reactor. (author)

Statewide ban on recreational fires resulted in a significant decrease in campfire-related summer burn center admissions.

Science.gov (United States)

Hoang, David Manh; Reid, Dixie; Lentz, Christopher William

2013-01-01

Every summer, there is an increase in the number of burn injuries caused by accidents around campfires. Because of the prevalence of drought, high winds, and uncontrolled wild fires, a statewide ban on recreational fires was instituted in New Mexico from June to July 2011. We hypothesized that this legislation would have a significant impact on burn admissions caused by campfire-related injuries. A retrospective review of summer admissions to a state burn center was conducted to assess the effect of this ban on recreational fire injuries, and these data were compared with that of the previous summer when no ban was in effect. All burn admissions to a state burn center were reviewed from Memorial Day to Labor Day in 2010 and 2011. Data collected included cause, % TBSA, age, days of hospitalization, intensive care unit days, and total surface area grafted. Nonparametric statistical analysis was performed with Fisher exact test for dichotomous data and Mann-Whitney test for continuous data with significance at P fires during the study period (n = 14 [17%] in 2010 and 4 [5%] in 2011; P = .02). This resulted in a decrease in the number of patient-days from 91 in 2010 to 25 in 2011. Half of the camp fire admissions required skin grafts to definitively close the wounds (6/14 in 2010 and 2/4 in 2011). Recreational fire bans targeted at controlling wildfires during conditions favoring rapid spread were associated with a 3- to 4-fold decrease in campfire-related burn admissions. Compared with a summer when no fire ban was in effect, the number of patient-days decreased from 91 to 25.

Role of burning season on initial understory vegetation response to prescribed fire in a mixed conifer forest

Science.gov (United States)

Knapp, E.E.; Schwilk, D.W.; Kane, J.M.; Keeley, J.E.

2007-01-01

Although the majority of fires in the western United States historically occurred during the late summer or early fall when fuels were dry and plants were dormant or nearly so, early-season prescribed burns are often ignited when fuels are still moist and plants are actively growing. The purpose of this study was to determine if burn season influences postfire vegetation recovery. Replicated early-season burn, late-season burn, and unburned control units were established in a mixed conifer forest, and understory vegetation was evaluated before and after treatment. Vegetation generally recovered rapidly after prescribed burning. However, late-season burns resulted in a temporary but significant drop in cover and a decline in species richness at the 1 m 2 scale in the following year. For two of the several taxa that were negatively affected by burning, the reduction in frequency was greater after late-season than early-season burns. Early-season burns may have moderated the effect of fire by consuming less fuel and lessening the amount of soil heating. Our results suggest that, when burned under high fuel loading conditions, many plant species respond more strongly to differences in fire intensity and severity than to timing of the burn relative to stage of plant growth. ?? 2007 NRC.

NOx Control Options and Integration for US Coal Fired Boilers

Energy Technology Data Exchange (ETDEWEB)

Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

2003-06-30

This is the twelfth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. During this quarter, a new effort was begun on the development of a corrosion management system for minimizing the impacts of low NOx combustion systems on waterwalls; a kickoff meeting was held at the host site, AEP's Gavin Plant, and work commenced on fabrication of the probes. FTIR experiments for SCR catalyst sulfation were finished at BYU and indicated no vanadium/vanadyl sulfate formation at reactor conditions. Improvements on the mass-spectrometer system at BYU have been made and work on the steady state reactor system shakedown neared completion. The slipstream reactor continued to operate at AEP's Rockport plant; at the end of the quarter, the catalysts had been exposed to flue gas for about 1000 hours. Some operational problems were addressed that enable the reactor to run without excessive downtime by the end of the quarter.

Decoupled numerical simulation of a solid fuel fired retort boiler

International Nuclear Information System (INIS)

Ryfa, Arkadiusz; Buczynski, Rafal; Chabinski, Michal; Szlek, Andrzej; Bialecki, Ryszard A.

2014-01-01

The paper deals with numerical simulation of the retort boiler fired with solid fuel. Such constructions are very popular for heating systems and their development is mostly based on the designer experience. The simulations have been done in ANSYS/Fluent package and involved two numerical models. The former deals with a fixed-bed combustion of the solid fuel and free-board gas combustion. Solid fuel combustion is based on the coal kinetic parameters. This model encompasses chemical reactions, radiative heat transfer and turbulence. Coal properties have been defined with user defined functions. The latter model describes flow of water inside a water jacked that surrounds the combustion chamber and flue gas ducts. The novelty of the proposed approach is separating of the combustion simulation from the water flow. Such approach allows for reducing the number of degrees of freedom and thus lowering the necessary numerical effort. Decoupling combustion from water flow requires defining interface boundary condition. As this boundary condition is unknown it is adjusted iteratively. The results of the numerical simulation have been successfully validated against measurement data. - Highlights: • New decoupled modelling of small scale boiler is proposed. • Fixed-bed combustion model based on kinetic parameters is introduced. • Decoupling reduced the complexity of the model and computational time. • Simple and computationally inexpensive coupling algorithm is proposed. • Model is successfully validated against measurements

MINIMIZATION OF NO EMISSIONS FROM MULTI-BURNER COAL-FIRED BOILERS; FINAL

International Nuclear Information System (INIS)

E.G. Eddings; A. Molina; D.W. Pershing; A.F. Sarofim; T.H. Fletcher; H. Zhang; K.A. Davis; M. Denison; H. Shim

2002-01-01

The focus of this program is to provide insight into the formation and minimization of NO(sub x) in multi-burner arrays, such as those that would be found in a typical utility boiler. Most detailed studies are performed in single-burner test facilities, and may not capture significant burner-to-burner interactions that could influence NO(sub x) emissions. Thus, investigations of such interactions were made by performing a combination of single and multiple burner experiments in a pilot-scale coal-fired test facility at the University of Utah, and by the use of computational combustion simulations to evaluate full-scale utility boilers. In addition, fundamental studies on nitrogen release from coal were performed to develop greater understanding of the physical processes that control NO formation in pulverized coal flames-particularly under low NO(sub x) conditions. A CO/H(sub 2)/O(sub 2)/N(sub 2) flame was operated under fuel-rich conditions in a flat flame reactor to provide a high temperature, oxygen-free post-flame environment to study secondary reactions of coal volatiles. Effects of temperature, residence time and coal rank on nitrogen evolution and soot formation were examined. Elemental compositions of the char, tar and soot were determined by elemental analysis, gas species distributions were determined using FTIR, and the chemical structure of the tar and soot was analyzed by solid-state(sup 13)C NMR spectroscopy. A laminar flow drop tube furnace was used to study char nitrogen conversion to NO. The experimental evidence and simulation results indicated that some of the nitrogen present in the char is converted to nitric oxide after direct attack of oxygen on the particle, while another portion of the nitrogen, present in more labile functionalities, is released as HCN and further reacts in the bulk gas. The reaction of HCN with NO in the bulk gas has a strong influence on the overall conversion of char-nitrogen to nitric oxide; therefore, any model that

Grate monitoring systems, state of the art; Metoder foer rosteroevervakning, dagslaegesbestaemning

Energy Technology Data Exchange (ETDEWEB)

Blom, Elisabet [Aaf Processdesign AB, Linkoeping (Sweden)

2001-01-01

During a number of years research and development projects have been made to present methods of monitoring the grate in a grate fired boiler. The monitoring is interesting in order to be able to increase efficiency, increase burn-out of ash, improve the status of emissions, improve transportation of ash and fuel through the furnace, reduce costs for operation and maintenance, handle greater loads etc. Improvement of the combustion has been concentrated to the development of the gas phase combustion. In the past few years the computer development has progressed rapidly and the use of optical monitoring methods have been made possible for monitoring grates. To analyse state of the art of optical grate monitoring systems three different methods have been used, literature search, inquiry where plant owners were asked if they have used grate monitoring systems and if so what experiences they have, and interviews with scientists and users. The inquiry investigation was made during spring 2000 and supplemented with a few known users of grate monitoring systems in august 2000. The interviews were made during august 2000. The methods which have been examined are: Video monitoring; Computer vision; IR-pyrometry; IR-camera technology; Laser measuring methods; Acoustic pyrometry. The survey showed that video monitoring is useful to monitor the fuel bed and an aid to the operators. A good cooling and cleansing system is essential to make the system reliable. If the system is aided with computer vision the computer will show numbers which can be used in the control system. These have been tried at a couple of sites but the system is still being developed and no sites uses this function fully automated. Infrared measurements have been tried in number of research projects. The IR-pyrometer technique is good for measuring temperature but the reliability is too low for some of the users. IR-cameras are used in several waste incineration plants to control the combustion. The systems

Quantitative risk assessment of continuous liquid spill fires based on spread and burning behaviours

DEFF Research Database (Denmark)

Zhao, Jinlong; Huang, Hong; Li, Yuntao

2017-01-01

Spill fires usually occur during the storage and transportation of hazardous materials, posing a threat to the people and environment in their immediate proximity. In this paper, a classical Quantitative Risk Assessment (QRA) method is used to assess the risk of spill fires. In this method......, the maximum spread area and the steady burning area are introduced as parameters to clearly assess the range of influence of the spill fire. In the calculations, a modified spread model that takes into consideration the burning rate variation is established to calculate the maximum spread area. Furthermore......, large-scale experiments of spill fires on water and a glass sheet were conducted to verify the accuracy and application of the model. The results show that the procedure we developed can be used to quantitatively calculate the risk associated with a continuous spill fire....

Cleaning of biomass derived product gas for engine applications and for co-firing in PC-boilers

Energy Technology Data Exchange (ETDEWEB)

Kurkela, E; Staahlberg, P; Laatikainen-Luntama, J [VTT Energy, Espoo (Finland). Energy Production Technologies; and others

1997-10-01

The conventional fluidized-bed combustion has become commercially available also to relatively small scale (5 MWe), but this technology has rather low power-to-heat ratio and consequently it`s potential is limited to applications where district or process heat is the main product. Thus, there seems to be a real need to develop more efficient methods for small-scale power production from biomass. Gasification diesel power plant is one alternative for the small-scale power production, which has clearly higher power-to-heat ratio than can be reached in conventional steam cycles. The main technical problem in this process is the gas cleaning from condensable tars. In addition to the diesel-power plants, there are several other interesting applications for atmospheric-pressure clean gas technology. One alternative for cost-effective biomass utilization is co-firing of biomass derived product gas in existing pulverized coal fired boilers (or other types of boilers and furnaces). The aim of the project is to develop dry gas cleaning methods for gasification-diesel power plants and for other atmospheric-pressure applications of biomass and waste gasification. The technical objectives of the project are as follows: To develop and test catalytic gas cleaning methods for engine. To study the removal of problematic ash species of (CFE) gasification with regard to co-combustion of the product gas in PC boilers. To evaluate the technical and economical feasibility of different small-scale power plant concepts based on fixed-bed updraft and circulating fluidized- bed gasification of biomass and waste. (orig.)

Thermal remote sensing of active vegetation fires and biomass burning events [Chapter 18

Science.gov (United States)

Martin J. Wooster; Gareth Roberts; Alistair M.S. Smith; Joshua Johnston; Patrick Freeborn; Stefania Amici; Andrew T. Hudak

2013-01-01

Thermal remote sensing is widely used in the detection, study, and management of biomass burning occurring in open vegetation fires. Such fires may be planned for land management purposes, may occur as a result of a malicious or accidental ignition by humans, or may result from lightning or other natural phenomena. Under suitable conditions, fires may spread rapidly...

Effect of Thermal Storage on the Performance of a Wood Pellet-fired Residential Boiler

Energy Technology Data Exchange (ETDEWEB)

Thomas, Butcher [Brookhaven National Laboratory (BNL), Upton, NY (United States). Sustainable Energy Technologies Dept.

2017-08-31

Interest in the direct use of biomass for thermal applications as a renewable technology is increasing as is also focus on air pollutant emissions from these sources and methods to minimize the impact. This work has focused on wood pellet-fired residential boilers, which are the cleanest fuel in this category. In the residential application the load varies strongly over the course of a year and a high fraction of the load is typically under 15% of the maximum boiler capacity. Thermal storage can be used even with boilers which have modulation capacity typically to 30% of the boiler maximum. One common pellet boiler was tested at full load and also at the minimum load used in the U.S. certification testing (15%). In these tests the load was steady over the test period. Testing was also done with an emulated load profile for a home in Albany, N.Y. on a typical January, March, and April day. In this case the load imposed on the boiler varied hourly under computer control, based on the modeled load for the example case used. The boiler used has a nominal output of 25 kW and a common mixed hardwood/softwood commercial pellet was used. Moisture content was 3.77%. A dilution tunnel approach was used for the measurement of particulate emissions, in accordance with U.S. certification testing requirements. The test results showed that the use of storage strongly reduces cycling rates under part load conditions. The transients which occur as these boilers cycle contribute to increased particulate emissions and reduced efficiency. The time period of a full cycle at a given load condition can be increased by increasing the storage tank volume and/or increasing the control differential range. It was shown that increasing the period strongly increased the measured efficiency and reduced the particulate emission (relative to the no storage case). The impact was most significant at the low load levels. Storage tank heat loss is shown to be a significant factor in thermal efficiency

Effects of a fast-burning spring fire on the ground-dwelling spider ...

African Journals Online (AJOL)

Fire is widely used as a management strategy in grasslands to maintain vegetation structure and improve grazing quality for large herbivores. The impacts of burning on invertebrates in South Africa remain poorly understood. A study was initiated in spring 2005 to determine the impact of a fast hot burn on ground-dwelling ...

Educational materials used for education in forest fires and preventive burning in Baccalaureate

Directory of Open Access Journals (Sweden)

S. Montoya

2013-09-01

Full Text Available This work includes various aspects of teaching in Secondary Education and Baccalaureate rarely on the agenda: forest fires and prescribed burns. It includes a proposal of training materials for the study and awareness of students about the serious problem posed by wildfires and how we can avoid them. Within the latter, the importance of controlled burning for preventing these fires is highlighted, which, as it has been shown when trying, is an unknown aspect for them. This test was to see if after the educational intervention previous ideas were modified.

Improved combustion performance of waste-fired FB-boilers -The influence of the dynamics of the bed on the air-/fuel interaction; Foerbaettrad foerbraenningsprestanda vid avfallsfoerbraenning i FB-pannor -Baeddynamikens inverkan paa luft-/braensleomblandningen

Energy Technology Data Exchange (ETDEWEB)

Olsson, Johanna (Hoegskolan i Boraas (Sweden)); Pallares, David; Thunman, Henrik; Johnsson, Filip (Chalmers (Sweden)); Andersson, Bengt-Aake (E.on/Hoegskolan i Boraas (Sweden)); Victoren, Anders (Metso Power AB (Sweden)); Johansson, Andreas (SP, Boraas (Sweden))

2010-07-01

One of the key benefits of fluidized bed combustion is that the bed - through mixing of fuel and air and accumulated heat - facilitates combustion at low stoichiometry and with low emissions. Even so, it is not unusual that waste-fired FB-boilers are operated at 6-8% oxygen that corresponds to 30-40% higher flows of gas than theoretically needed. In addition to that and in comparison to grate furnaces, FB-boiler can cause high pressure drop losses because of the fluidization of the bottom bed, which in turn are associated with high costs for power (fans). This work aims therefore at increasing the knowledge for how the dynamics of the bed affects the air and fuel mixture. Methods to explain and characterize the phenomenon have been derived within this work showing: - Distribution of air in a bed for various cases and the influence of pressure drop, bed height and fluidization velocity - A semi-empiric method to calculate an even bubble distribution - The relation between fluidization and fuel distribution for various fluidization flows and fuels - Dispersion rates for various fuels - Volatilization rates for waste in relation to biomass The result can be useful when optimizing units, for instance through finding as low pressure drops as possible with an even bubble distribution, low risk for sintering and unwanted emissions. The work has thereby reached its ultimate goal of increasing the generic knowledge about waste combustion in FB-boiler

EFFICIENCY IMPROVEMENT IN INDUSTRIAL BOILER BY FLUE GAS DUCT INSULATION

OpenAIRE

Sanjay H. Zala

2017-01-01

Now a days in industry major losses are find out so here we calculate these losses and find out efficiency of boiler. Boiler efficiency and energy losses from boiler are important parameter for any industry using boiler. In this work a detailed analysis was carried out for boiler at Anish Chemicals Bhavnagar. It is a combined water and fire tube boiler using biomass coal as fuel. Boiler efficiency calculated by direct method is in range of (78.5% to 81.6%). Major losses from boiler are heat ...

Numerical investigation on the flow, combustion, and NOX emission characteristics in a 660 MWe tangential firing ultra-supercritical boiler

Directory of Open Access Journals (Sweden)

Wenjing Sun

2016-02-01

Full Text Available A three-dimensional numerical simulation was carried out to study the pulverized-coal combustion process in a tangentially fired ultra-supercritical boiler. The realizable k-ε model for gas coupled with discrete phase model for coal particles, P-1 radiation model for radiation, two-competing-rates model for devolatilization, and kinetics/diffusion-limited model for combustion process are considered. The characteristics of the flow field, particle motion, temperature distribution, species components, and NOx emissions were numerically investigated. The good agreement of the measurements and predictions implies that the applied simulation models are appropriate for modeling commercial-scale coal boilers. It is found that an ideal turbulent flow and particle trajectory can be observed in this unconventional pulverized-coal furnace. With the application of over-fire air and additional air, lean-oxygen combustion takes place near the burner sets region and higher temperature at furnace exit is acquired for better heat transfer. Within the limits of secondary air, more steady combustion process is achieved as well as the reduction of NOx. Furthermore, the influences of the secondary air, over-fire air, and additional air on the NOx emissions are obtained. The numerical results reveal that NOx formation attenuates with the decrease in the secondary air ratio (γ2nd and the ratio of the additional air to the over-fire air (γAA/γOFA was within the limits.

Joint simulation of regional areas burned in Canadian forest fires: A Markov Chain Monte Carlo approach

Science.gov (United States)

Steen Magnussen

2009-01-01

Areas burned annually in 29 Canadian forest fire regions show a patchy and irregular correlation structure that significantly influences the distribution of annual totals for Canada and for groups of regions. A binary Monte Carlo Markov Chain (MCMC) is constructed for the purpose of joint simulation of regional areas burned in forest fires. For each year the MCMC...

Post-fire burn severity and vegetation response following eight large wildfires across the Western United States

Science.gov (United States)

Leigh B. Lentile; Penelope Morgan; Andrew T. Hudak; Michael J. Bobbitt; Sarah A. Lewis; Alistair M. S. Smith; Peter R. Robichaud

2007-01-01

Vegetation response and burn severity were examined following eight large wildfires that burned in 2003 and 2004: two wildfires in California chaparral, two each in dry and moist mixed-conifer forests in Montana, and two in boreal forests in interior Alaska. Our research objectives were: 1) to characterize one year post-fire vegetation recovery relative to initial fire...

Analysis of an effective solution to excessive heat supply in a city primary heating network using gas-fired boilers for peak-load compensation

Energy Technology Data Exchange (ETDEWEB)

Wang, Hai-Chao; Jiao, Wen-Ling; Zou, Ping-Hua; Liu, Jing-Cheng [School of Municipal and Environmental Engineering, Harbin Institute of Technology, mail box 2645, 202 Haihe Road, Nangang District, Harbin 150090 (China)

2010-11-15

Through investigation of the Dengfeng heating network in the city of Daqing, China, for the 2007-2008 heating season, we found serious problems of excessive heat supply in the primary heating network. Therefore, we propose the application of gas-fired boilers in underperforming heating substations as peak-load heat sources to effectively adapt to the regulation demands of seasonal heat-load fluctuations and reduce the excessive heat supply. First, we calculated the excessive heat supply rates (EHSRs) of five substations using detailed investigative data. We then discussed the feasibility of the proposed scheme providing energy savings from both energetic and exergetic points of view. The results showed that the average EHSR of the five substations between January and March was 20.57% of the gross heat production but consequently reduced to 6.24% with the installation of the gas-fired boilers. Therefore, the combined heating scheme with coal as the basic heat-source and gas-fired boilers as peak-load heat sources is energy-efficient to some extent, although requires the use of natural gas. Meanwhile, the exergy decreased by 10.97%, which indicates that the combined heating scheme effectively reduces the primary energy consumption and pollutant emission of the heating systems. (author)

Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin, USA

Directory of Open Access Journals (Sweden)

Kimberly Yazzie

2017-02-01

Full Text Available This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB, Oregon, using the precipitation runoff modeling system. Ten global climate models using Coupled Intercomparison Project Phase 5 experiments with Representative Concentration Pathways (RCP 4.5 and 8.5 were used to simulate the effects of climate and fire-burns on runoff behavior throughout the 21st century. We observed the center timing (CT of flow, seasonal flows, snow water equivalent (SWE and basin recharge. In the upper URB, hydrologic regime shifts from a snow-rain-dominated to rain-dominated basin. Ensemble mean CT occurs 27 days earlier in RCP 4.5 and 33 days earlier in RCP 8.5, in comparison to historic conditions (1980s by the end of the 21st century. After forest cover reduction in the 2080s, CT occurs 35 days earlier in RCP 4.5 and 29 days earlier in RCP 8.5. The difference in mean CT after fire-burns may be due to projected changes in the individual climate model. Winter flow is projected to decline after forest cover reduction in the 2080s by 85% and 72% in RCP 4.5 and RCP 8.5, in comparison to 98% change in ensemble mean winter flows in the 2080s before forest cover reduction. The ratio of ensemble mean snow water equivalent to precipitation substantially decreases by 81% and 91% in the 2050s and 2080s before forest cover reduction and a decrease of 90% in RCP 4.5 and 99% in RCP 8.5 in the 2080s after fire-burns. Mean basin recharge is 10% and 14% lower in the 2080s before fire-burns and after fire-burns, and it decreases by 13% in RCP 4.5 and decreases 22% in RCP 8.5 in the 2080s in comparison to historical conditions. Mixed results for recharge after forest cover reduction suggest that an increase may be due to the size of burned areas, decreased canopy interception and less evaporation occurring at the watershed surface, increasing the potential for infiltration. The effects of fire on the watershed system are

Corrosion behaviour of boiler tube materials during combustion of fuels containing Zn and Pb

Energy Technology Data Exchange (ETDEWEB)

Bankiewicz, D.

2012-11-01

Many power plants burning challenging fuels such as waste-derived fuels experience failures of the superheaters and/or increased waterwall corrosion due to aggressive fuel components already at low temperatures. To minimize corrosion problems in waste-fired boilers, the steam temperature is currently kept at a relatively low level which drastically limits power production efficiency. The elements found in deposits of waste and waste-derived fuels burning boilers that are most frequently associated with high-temperature corrosion are: Cl, S, and there are also indications of Br; alkali metals, mainly K and Na, and heavy metals such as Pb and Zn. The low steam pressure and temperature in waste-fired boilers also influence the temperature of the waterwall steel which is nowadays kept in the range of 300 deg C - 400 deg C. Alkali chloride (KCl, NaCl) induced high-temperature corrosion has not been reported to be particularly relevant at such low material temperatures, but the presence of Zn and Pb compounds in the deposits have been found to induce corrosion already in the 300 deg C - 400 deg C temperature range. Upon combustion, Zn and Pb may react with Cl and S to form chlorides and sulphates in the flue gases. These specific heavy metal compounds are of special concern due to the formation of low melting salt mixtures. These low melting, gaseous or solid compounds are entrained in the flue gases and may stick or condense on colder surfaces of furnace walls and superheaters when passing the convective parts of the boiler, thereby forming an aggressive deposit. A deposit rich in heavy metal (Zn, Pb) chlorides and sulphates increases the risk for corrosion which can be additionally enhanced by the presence of a molten phase. The objective of this study was to obtain better insight into high-temperature corrosion induced by Zn and Pb and to estimate the behaviour and resistance of some boiler superheater and waterwall materials in environments rich in those heavy metals

Burning radionuclide question. What happens to iodine, cesium and chlorine in biomass fires?

International Nuclear Information System (INIS)

Amiro, B.D.; Sheppard, S.C.; Johnston, F.L.; Evenden, W.G.; Harris, D.R.

1996-01-01

Fires can mobilize radionuclides from contaminated biomass through suspension of gases and particles in the atmosphere or solubilization and enrichment of the ash. Field and laboratory burns were conducted to determine the fate of I, Cs and Cl in biomass fires. Straw, wood, peat, dulse (seaweed) and radish plants were combusted with temperatures varying from 160 to 1000C, representing the normal range of field fire temperatures. Loss to the atmosphere increased with fire temperature and during a typical field fire, 80 - 90% of the I and Cl, and 40 - 70% of the Cs was lost to the atmosphere. The remainder was left behind in the ash and was soluble. Typically, the ash was enriched in I by a factor of two to three, with higher enrichments of Cs and lower enrichments of Cl, when compared to the initial fuel concentration during field burns. Most of the I was lost to the atmosphere as a gas. If the elements were radioactive isotopes, such as 129 I, 137 Cs and 36 Cl, fires could cause an increased radiological dose to people through inhalation, exposure to ash, or ingestion of plants because of increased uptake of ash leachate

Field performance of wood-burning and coal-burning appliances in Crested Butte during the 1989-90 heating season. Final report

International Nuclear Information System (INIS)

Jaasma, D.R.; Champion, M.R.; Gundappa, M.

1991-10-01

The field performance of woodburning and coalburning appliances in and around Crested Butte, CO, has been evaluated. Measurements included particulate matter (PM), carbon monoxide (CO), and weekly average burn rates. Woodburning appliances included conventional airtight stoves, EPA-certified catalytic stoves, and EPA-certified noncatalytic stoves. Compared to the emissions measured from conventional stoves, the certified stoves reduced PM emission factors (g/kg) by 53% and CO emission factors by 49%. Coalburning appliances included a commercial scale boiler, a residential stoker, and hand-fired coalstove. The coalburning appliances were compared to conventional woodstoves on a grams of pollutant per joule of heat output basis. The automatically stoked coal appliances reduced PM and CO emissions by roughly 84% and 85%, respectively. The hand-fired stove was cleaner than expected, reducing PM by 55% and CO by 27%

Spatial interpolation and simulation of post-burn duff thickness after prescribed fire

Science.gov (United States)

Peter R. Robichaud; S. M. Miller

1999-01-01

Prescribed fire is used as a site treatment after timber harvesting. These fires result in spatial patterns with some portions consuming all of the forest floor material (duff) and others consuming little. Prior to the burn, spatial sampling of duff thickness and duff water content can be used to generate geostatistical spatial simulations of these characteristics....

The influence of burn severity on post-fire vegetation recovery and albedo change during early succession in North American boreal forests

Science.gov (United States)

Jin, Y.; Randerson, J. T.; Goetz, S. J.; Beck, P. S.; Loranty, M. M.; Goulden, M.

2011-12-01

Severity of burning can influence multiple aspects of forest composition, carbon cycling, and climate forcing. We quantified how burn severity affected vegetation recovery and albedo change during early succession in Canadian boreal regions by combining satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Canadian Large Fire Data Base (LFDB). We used the difference Normalized Burn Ratio (dNBR) and changes in spring albedo derived from MODIS 500m albedo product as measures of burn severity. We found that the most severe burns had the greatest reduction in summer EVI in first year after fire, indicating greater loss of vegetation cover immediately following fire. By 5-7 years after fire, summer EVI for all severity classes had recovered to within 90-110% of pre-fire levels. Burn severity had a positive effect on the increase of post-fire spring albedo during the first 7 years after fire, and a shift from low to moderate or moderate to severe fires led to amplification of the post-fire albedo increase by approximately 30%. Fire-induced increases in both spring and summer albedo became progressively larger with stand age from years 1-7, with the trend in spring albedo likely driven by continued losses of needles and branches from trees killed by the fire (and concurrent losses of black carbon coatings on remaining debris), and the summer trend associated with increases in leaf area of short-stature herbs and shrubs. Our results suggest that increases in burn severity and carbon losses observed in some areas of boreal forests (e.g., Turetsky et al., 2011) may be at least partly offset by increases in negative forcing associated with changes in surface albedo.

Staged combustion - main method for suppressing nitrogen oxides in pulverized-coal fired boilers

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (USSR))

1989-08-01

Describes principles behind staged combustion, which is based on organizing furnace operations so that only part of the air from the fuel is taken into the furnace. The remaining air, which is needed for combustion, is fed as a tertiary blast jet into the intermediate flame zone. Following inflammation and combustion of the volatile matter, the oxygen concentration in the flame drops sharply causing a retardation of the oxidation reactions forming NO and an intensification of the reactions causing the nitrogen-containing radicals NH{sub i} and CN to be converted into N{sub 2}. When the reducing agents CO, H{sub 2} and CH{sub 4} are present in certain flame zones, even the nitrogen oxide is reduced to N{sub 2}. The NO concentrations in the flame are reduced until the jet of tertiary air is introduced. Discusses with reference to practice in the USA and Western Europe how to achieve maximum effect of this method for different types of boiler and presents the results of observations of the introduction of staged combustion to the BKZ-210-140 boiler burning Kuznetsk gassy coal. 5 refs.

Assessment of nitrogen oxide emission for designing boilers fired with coal dust

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.; Gusev, L.N.; Babii, V.I.

1983-09-01

A method for forecasting emission of nitrogen oxides from steam boilers fired with coal is described. The method produces accurate results when nitrogen oxide emission from furnaces with straight-flow burners and turbulent-type burners fired with coal dusts is forecast. Oxides formed by decomposition of chemical compounds in coal (so-called 'fuel' nitrogen oxides) and nitrogen oxides formed by oxidation of molecular nitrogen by atomic oxygen (so-called 'thermal' nitrogen oxides) are evaluated. Zones in which the two types of nitrogen oxide are formed in flames are characterized. Factors which influence formation of nitrogen oxides in a furnace are evaluated: excess air, flue gas recirculation, design of a furnace and burners, movement of air and coal dust mixture in a furnace, temperature, methods for coal dust preparation, coal dust properties. Equations for forecasting emission of nitrogen oxides from furnaces are derived. Nomograms for easy calculation of emission are also given. Examples of using the method for forecasting emission of nitrogen oxides from furnaces fired with coal from the Kuzbass, the Donbass and Ehkibastuz are discussed. Comparisons of emission of nitrogen oxides calculated on the basis of the method and emission determined experimentally show that forecasting accuracy is high and errors do not exceed 10%. 5 references.

Computational intelligence approach for NOx emissions minimization in a coal-fired utility boiler

International Nuclear Information System (INIS)

Zhou Hao; Zheng Ligang; Cen Kefa

2010-01-01

The current work presented a computational intelligence approach used for minimizing NO x emissions in a 300 MW dual-furnaces coal-fired utility boiler. The fundamental idea behind this work included NO x emissions characteristics modeling and NO x emissions optimization. First, an objective function aiming at estimating NO x emissions characteristics from nineteen operating parameters of the studied boiler was represented by a support vector regression (SVR) model. Second, four levels of primary air velocities (PA) and six levels of secondary air velocities (SA) were regulated by using particle swarm optimization (PSO) so as to achieve low NO x emissions combustion. To reduce the time demanding, a more flexible stopping condition was used to improve the computational efficiency without the loss of the quality of the optimization results. The results showed that the proposed approach provided an effective way to reduce NO x emissions from 399.7 ppm to 269.3 ppm, which was much better than a genetic algorithm (GA) based method and was slightly better than an ant colony optimization (ACO) based approach reported in the earlier work. The main advantage of PSO was that the computational cost, typical of less than 25 s under a PC system, is much less than those required for ACO. This meant the proposed approach would be more applicable to online and real-time applications for NO x emissions minimization in actual power plant boilers.

DESIGN REPORT: LOW-NOX BURNERS FOR PACKAGE BOILERS

Science.gov (United States)

The report describes a low-NOx burner design, presented for residual-oil-fired industrial boilers and boilers cofiring conventional fuels and nitrated hazardous wastes. The burner offers lower NOx emission levels for these applications than conventional commercial burners. The bu...

The experience of burning the high-moistured waste of biomass conversion

Energy Technology Data Exchange (ETDEWEB)

Fincker, F.Z.; Zysin, L.V.; Kubyshkin, I.B. [MGVP Polytechenergo, St. Petersburg (Russian Federation)

1993-12-31

Industrially developed countries have a large stock of operating boiler plants to utilize timber industry waste materials (bagasse, bark, wood chips, hydrolytic lignine, sawdust, etc.) for biogenesis of energy. Standard combustion methods employing a bed or flare process cannot guarantee a reliable and economic boiler plant operation with abruptly changing biomass characteristic features. The moisture content in bark or lignin can vary from 50 to 75% during an hour. Particle sizes can vary from powdered to very large, and can have a hundred thousand times size difference. Large metal and mineral inclusions into the starting fuel also complicate the process. The low-temperature whirling combustion technology developed in Russia was taken as a basic. An economical and stable operation of boilers has been achieved by means of up-to-date vortex chamber aerial dynamics, the use of unique devices of fuel feed and preparation with screening the waste materials into sizes. The firing chamber is equipped with a multi-chamber device where screening and fuel particles preparation with the removal of noncombustible inclusions take place. At presenting the firing chamber with multi-step process of burning is in operation with 20 boilers. The firm {open_quotes}POLYTECHENERGO,{close_quotes} a developer and producer of such equipment, carries out the modernization of the boiler plant without changes in the its thermal circuit. In most of cases no replacement of draught means is needed. Competitive with the proposed low-temperature whirling technological process can be only a fluidized bed process, but due to the complexity in service, low reliability, high energy expenditures, such chambers at present are very few. The capital expenses one existing boilers updating for a fluidized bed process exceed the expenses on a low-temperature whirling process by 15--20 fold.

Start-up emissions from residential down-draught wood log boilers

Energy Technology Data Exchange (ETDEWEB)

Pettersson, E. (Luleaa Univ. of Technology (Sweden). Energy Technology Centre in Piteaa), Email: esbjorn.pettersson@ltu.se

2009-07-01

Start-up emissions can be substantial and even dominating in real use. There are few published investigations regarding the relative importance of different parameters on the start-up emissions. It has though recently been stated that for down-draught boilers, best results are achieved if the wood charge is ignited fairly close to the secondary chamber. The objective of the experimental work was to evaluate the effect of different fuel and design parameters on the start-up emissions, using experimental design which enables a direct comparison between different parameters, using three levels of preheating of secondary air, electric preheating of primary air, different moisture and size of the start wood as well as different amounts of birch bark, which was used to spread the fire during the start. The boiler did not use a bypass damper and the full fuel charge was added before igniting the start wood through an ignition door situated slightly above the grate. The only significant results for the four parameters were that smaller and drier start wood gave lower start-up emissions. Extra amount of birch bark gave the same result. The most important parameters are the fuel parameters, which mean that the result is generally applicable. (orig.)

Temperature and burning history affect emissions of greenhouse gases and aerosol particles from tropical peatland fire

Science.gov (United States)

Kuwata, Mikinori; Kai, Fuu Ming; Yang, Liudongqing; Itoh, Masayuki; Gunawan, Haris; Harvey, Charles F.

2017-01-01

Tropical peatland burning in Asia has been intensifying over the last decades, emitting huge amounts of gas species and aerosol particles. Both laboratory and field studies have been conducted to investigate emission from peat burning, yet a significant variability in data still exists. We conducted a series of experiments to characterize the gas and particulate matter emitted during burning of a peat sample from Sumatra in Indonesia. Heating temperature of peat was found to regulate the ratio of CH4 to CO2 in emissions (ΔCH4/ΔCO2) as well as the chemical composition of particulate matter. The ΔCH4/ΔCO2 ratio was larger for higher temperatures, meaning that CH4 emission is more pronounced at these conditions. Mass spectrometric analysis of organic components indicated that aerosol particles emitted at higher temperatures had more unsaturated bonds and ring structures than that emitted from cooler fires. The result was consistently confirmed by nuclear magnetic resonance analysis. In addition, CH4 emitted by burning charcoal, which is derived from previously burned peat, was lower by at least an order of magnitude than that from fresh peat. These results highlight the importance of both fire history and heating temperature for the composition of tropical peat-fire emissions. They suggest that remote sensing technologies that map fire histories and temperatures could provide improved estimates of emissions.

Life extension of boilers using weld overlay protection

Energy Technology Data Exchange (ETDEWEB)

Lai, G; Hulsizer, P [Welding Services Inc., Norcross, GA (United States); Brooks, R [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

1999-12-31

The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

Life extension of boilers using weld overlay protection

Energy Technology Data Exchange (ETDEWEB)

Lai, G.; Hulsizer, P. [Welding Services Inc., Norcross, GA (United States); Brooks, R. [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

1998-12-31

The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

Continental-scale simulation of burn probabilities, flame lengths, and fire size distribution for the United States

Science.gov (United States)

Mark A. Finney; Charles W. McHugh; Isaac Grenfell; Karin L. Riley

2010-01-01

Components of a quantitative risk assessment were produced by simulation of burn probabilities and fire behavior variation for 134 fire planning units (FPUs) across the continental U.S. The system uses fire growth simulation of ignitions modeled from relationships between large fire occurrence and the fire danger index Energy Release Component (ERC). Simulations of 10,...

Computational fluid dynamics (CFD) modelling of coal/biomass co-firing in pulverised fuel boilers

Energy Technology Data Exchange (ETDEWEB)

Moghtaderi, B.; Meesri, C. [University of Newcastle, Callaghan, NSW (Australia). CRC for Coal in Sustainable Development, Dept. of Chemical Engineering

2002-07-01

The present study is concerned with computational fluid dynamics (CFD) modelling of coal/biomass blends co-fired under conditions pertinent to pulverised fuel (PF) boilers. The attention is particularly focused on the near burner zone to examine the impact of biomass on the flame geometry and temperature. The predictions are obtained by numerical solution of the conservation equations for the gas and particle phases. The gas phase is solved in the Eulerian domain using steady-state time-averaged Navier-Stokes equations while the solution of the particle phase is obtained from a series of Lagrangian particle tracking equations. Turbulence is modelled using the {kappa}-{epsilon} and Reynolds Stress models. The comparison between the predictions and experimental measurement reported in the literature resulted in a good agreement. Other influences of biomass co-firing are observed for fuel devolatilisation and burnout. 19 refs., 6 figs.

Ultrasonic boiler inspection and economic analysis guidelines

International Nuclear Information System (INIS)

Anon.

1987-01-01

Boiler tube failures cause approximately 6% availability loss of large fossil-fired power generating plants. This loss can be reduced by systematic approaches using ultrasonic examination and root cause failure analysis methods. Two projects sponsored by EPRI have provided utility engineers with guidelines for performing ultrasonic examinations and with details on 22 types of tube failure mechanisms. A manual has been published that provides descriptions of typical locations, superficial appearances, damage mechanisms, metallurgy, microstructural changes, likely root causes, and potential corrective actions. Application of the principles in the manual is being demonstrated in an EPRI-funded project at 10 electric utilities over the next two years. Guidelines have been published that prescribe the activities necessary for ultrasonic examinations of boiler tubes. Eight essential elements of a boiler examination should be performed to assure that possible economic benefits are obtained. Work was supported by EPRI under RP 1890 and RP 1865. A software package has been developed for effectively planning inspections for wall thinning in fossil-fired boiler tubing. The software assists in minimizing costs associated with maintenance, such as inspection and repair, while the life of the boiler is maximized

Social and Ecological Factors Influencing Attitudes Toward the Application of High-Intensity Prescribed Burns to Restore Fire Adapted Grassland Ecosystems

Directory of Open Access Journals (Sweden)

David Toledo

2013-12-01

Full Text Available Fire suppression in grassland systems that are adapted to episodic fire has contributed to the recruitment of woody species in grasslands worldwide. Even though the ecology of restoring these fire prone systems back to grassland states is becoming clearer, a major hurdle to the reintroduction of historic fires at a landscape scale is its social acceptability. Despite the growing body of literature on the social aspects of fire, an understanding of the human dimensions of applying high-intensity prescribed burns in grassland and savanna systems is lacking. We used structural equation modeling to examine how landowners' attitudes toward high-intensity prescribed burns are affected by previous experience with burning, perceptions of brush encroachment, land condition, proximity constraints, risk orientation, fire management knowledge and skill, access to fire management equipment, and subjective norms. Our results suggest that experience, risk taking orientation, and especially social norms, i.e., perceived support from others, when implementing prescribed burns play an important role in determining the attitudes of landowners toward the use of high-intensity prescribed burns. Concern over lack of skill, knowledge, and insufficient resources have a moderately negative effect on these attitudes. Our results highlight the importance of targeted engagement strategies to address risk perceptions, subjective norms, and landowner's concerns. With these concerns allayed, it is possible to increase the adoption of high-intensity prescribed burns that lead to landscape-scale grassland restoration and conservation.

Development of Computational Capabilities to Predict the Corrosion Wastage of Boiler Tubes in Advanced Combustion Systems

Energy Technology Data Exchange (ETDEWEB)

Kung, Steven; Rapp, Robert

2014-08-31

A comprehensive corrosion research project consisting of pilot-scale combustion testing and long-term laboratory corrosion study has been successfully performed. A pilot-scale combustion facility available at Brigham Young University was selected and modified to enable burning of pulverized coals under the operating conditions typical for advanced coal-fired utility boilers. Eight United States (U.S.) coals were selected for this investigation, with the test conditions for all coals set to have the same heat input to the combustor. In addition, the air/fuel stoichiometric ratio was controlled so that staged combustion was established, with the stoichiometric ratio maintained at 0.85 in the burner zone and 1.15 in the burnout zone. The burner zone represented the lower furnace of utility boilers, while the burnout zone mimicked the upper furnace areas adjacent to the superheaters and reheaters. From this staged combustion, approximately 3% excess oxygen was attained in the combustion gas at the furnace outlet. During each of the pilot-scale combustion tests, extensive online measurements of the flue gas compositions were performed. In addition, deposit samples were collected at the same location for chemical analyses. Such extensive gas and deposit analyses enabled detailed characterization of the actual combustion environments existing at the lower furnace walls under reducing conditions and those adjacent to the superheaters and reheaters under oxidizing conditions in advanced U.S. coal-fired utility boilers. The gas and deposit compositions were then carefully simulated in a series of 1000-hour laboratory corrosion tests, in which the corrosion performances of different commercial candidate alloys and weld overlays were evaluated at various temperatures for advanced boiler systems. Results of this laboratory study led to significant improvement in understanding of the corrosion mechanisms operating on the furnace walls as well as superheaters and reheaters in

Assessing the Impact of Fires on Air Quality in the Southeastern U.S. with a Unified Prescribed Burning Database

Science.gov (United States)

Garcia Menendez, F.; Afrin, S.

2017-12-01

Prescribed fires are used extensively across the Southeastern United States and are a major source of air pollutant emissions in the region. These land management projects can adversely impact local and regional air quality. However, the emissions and air pollution impacts of prescribed fires remain largely uncertain. Satellite data, commonly used to estimate fire emissions, is often unable to detect the low-intensity, short-lived prescribed fires characteristic of the region. Additionally, existing ground-based prescribed burn records are incomplete, inconsistent and scattered. Here we present a new unified database of prescribed fire occurrence and characteristics developed from systemized digital burn permit records collected from public and private land management organizations in the Southeast. This bottom-up fire database is used to analyze the correlation between high PM2.5 concentrations measured by monitoring networks in southern states and prescribed fire occurrence at varying spatial and temporal scales. We show significant associations between ground-based records of prescribed fire activity and the observational air quality record at numerous sites by applying regression analysis and controlling confounding effects of meteorology. Furthermore, we demonstrate that the response of measured PM2.5 concentrations to prescribed fire estimates based on burning permits is significantly stronger than their response to satellite fire observations from MODIS (moderate-resolution imaging spectroradiometer) and geostationary satellites or prescribed fire emissions data in the National Emissions Inventory. These results show the importance of bottom-up smoke emissions estimates and reflect the need for improved ground-based fire data to advance air quality impacts assessments focused on prescribed burning.

Up-date on cyclone combustion and cyclone boilers

Energy Technology Data Exchange (ETDEWEB)

Carmo, Felipe Alfaia do; Nogueira, Manoel Fernandes Martins; Rocha, Rodrigo Carnera Castro da; Gazel, Hussein Felix; Martins, Diego Henrique dos Reis [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Campus Universitario Jose da Silveira Netto], E-mails: mfmn@ufpa.br, mfmn@ufpa.br

2010-07-01

The boiler concept has been around for more than 70 years, and there are many types available. Boilers provide steam or hot water for industrial and commercial use. The Federal University of Para (UFPA) through the research group EBMA (Energy,Biomass and Environment) has been developing cyclonic furnace with a water wall, a boiler, aiming to use regional timbers (sawdust) and agro-industries residues as fuel to produce steam to be used in industrial processes as well as in power generation,. The use of cyclonic combustion for burning waste instead of burning in a fixed bed is mainly due to two factors efficiency improvement causing a more compact boiler and less risk of explosion, since their process does not generate an accumulation of volatile. Present state-of-art for commercial cyclone boilers has as set up a cyclone combustor with two combustion chambers, in fluid communication, where there ducts for supplying air and fuel directly into the first chamber and for forming a cyclonic flow pattern and a heat exchanger surrounding the second chamber for keeping low combustion temperature in both chambers. This paper shows the results of a literature review about design, construction and operation of cyclonic boilers using solid, liquid or gaseous fuel. This information has been used for the design of a cyclone boiler to be constructed at UFPA for research purposes and its basic concept is presented at the end of this article. (author)

Electrical design requirements for electrode boilers for nuclear plants

International Nuclear Information System (INIS)

Kempker, M.J.

1979-01-01

Medium-voltage steam electrode boilers, in the 20- to 50-MW range, have become an attractive alternative to comparable fossil-fueled boilers as a source of auxiliary steam during the startup and normal shutdown of nuclear power plants. The electrode boiler represents a favorable option because of environmental, fire protection, and licensing considerations. However, this electrical option brings some difficult design problems for which solutions are required in order to integrate the electrode boiler into the plant low resistance grounded power system. These considerations include the effects of an unbalanced electrode boiler on the performance of polyphase induction motors, boiler grounding for personnel safety, boiler neutral grounding, and ground relaying

Biomass Burning Emissions from Fire Remote Sensing

Science.gov (United States)

Ichoku, Charles

2010-01-01

Knowledge of the emission source strengths of different (particulate and gaseous) atmospheric constituents is one of the principal ingredients upon which the modeling and forecasting of their distribution and impacts depend. Biomass burning emissions are complex and difficult to quantify. However, satellite remote sensing is providing us tremendous opportunities to measure the fire radiative energy (FRE) release rate or power (FRP), which has a direct relationship with the rates of biomass consumption and emissions of major smoke constituents. In this presentation, we will show how the satellite measurement of FRP is facilitating the quantitative characterization of biomass burning and smoke emission rates, and the implications of this unique capability for improving our understanding of smoke impacts on air quality, weather, and climate. We will also discuss some of the challenges and uncertainties associated with satellite measurement of FRP and how they are being addressed.

Assessment of fire emission inventories during the South American Biomass Burning Analysis (SAMBBA) experiment

Science.gov (United States)

Pereira, Gabriel; Siqueira, Ricardo; Rosário, Nilton E.; Longo, Karla L.; Freitas, Saulo R.; Cardozo, Francielle S.; Kaiser, Johannes W.; Wooster, Martin J.

2016-06-01

Fires associated with land use and land cover changes release large amounts of aerosols and trace gases into the atmosphere. Although several inventories of biomass burning emissions cover Brazil, there are still considerable uncertainties and differences among them. While most fire emission inventories utilize the parameters of burned area, vegetation fuel load, emission factors, and other parameters to estimate the biomass burned and its associated emissions, several more recent inventories apply an alternative method based on fire radiative power (FRP) observations to estimate the amount of biomass burned and the corresponding emissions of trace gases and aerosols. The Brazilian Biomass Burning Emission Model (3BEM) and the Fire Inventory from NCAR (FINN) are examples of the first, while the Brazilian Biomass Burning Emission Model with FRP assimilation (3BEM_FRP) and the Global Fire Assimilation System (GFAS) are examples of the latter. These four biomass burning emission inventories were used during the South American Biomass Burning Analysis (SAMBBA) field campaign. This paper analyzes and inter-compared them, focusing on eight regions in Brazil and the time period of 1 September-31 October 2012. Aerosol optical thickness (AOT550 nm) derived from measurements made by the Moderate Resolution Imaging Spectroradiometer (MODIS) operating on board the Terra and Aqua satellites is also applied to assess the inventories' consistency. The daily area-averaged pyrogenic carbon monoxide (CO) emission estimates exhibit significant linear correlations (r, p > 0.05 level, Student t test) between 3BEM and FINN and between 3BEM_ FRP and GFAS, with values of 0.86 and 0.85, respectively. These results indicate that emission estimates in this region derived via similar methods tend to agree with one other. However, they differ more from the estimates derived via the alternative approach. The evaluation of MODIS AOT550 nm indicates that model simulation driven by 3BEM and FINN

Source profiles of particulate matter emissions from a pilot-scale boiler burning North American coal blends.

Science.gov (United States)

Lee, S W

2001-11-01

Recent awareness of suspected adverse health effects from ambient particulate matter (PM) emission has prompted publication of new standards for fine PM with aerodynamic diameter less than 2.5 microm (PM2.5). However, scientific data on fine PM emissions from various point sources and their characteristics are very limited. Source apportionment methods are applied to identify contributions of individual regional sources to tropospheric particulate concentrations. The existing industrial database developed using traditional source measurement techniques provides total emission rates only, with no details on chemical nature or size characteristics of particulates. This database is inadequate, in current form, to address source-receptor relationships. A source dilution system was developed for sampling and characterization of total PM, PM2.5, and PM10 (i.e., PM with aerodynamic diameter less than 10 pm) from residual oil and coal combustion. This new system has automatic control capabilities for key parameters, such as relative humidity (RH), temperature, and sample dilution. During optimization of the prototype equipment, three North American coal blends were burned using a 0.7-megawatt thermal (MWt) pulverized coal-fired, pilot-scale boiler. Characteristic emission profiles, including PM2.5 and total PM soluble acids, and elemental and carbon concentrations for three coal blends are presented. Preliminary results indicate that volatile trace elements such as Pb, Zn, Ti, and Se are preferentially enriched in PM2.5. PM2.5 is also more concentrated in soluble sulfates relative to total PM. Coal fly ash collected at the outlet of the electrostatic precipitator (ESP) contains about 85-90% PM10 and 30-50% PM2.5. Particles contain the highest elemental concentrations of Si and Al while Ca, Fe, Na, Ba, and K also exist as major elements. Approximately 4-12% of the materials exists as soluble sulfates in fly ash generated by coal blends containing 0.2-0.8% sulfur by mass

Co-firing coal and hospital waste in a circulating fluidized bed boiler

International Nuclear Information System (INIS)

Coulthard, E.J.; Korenberg, J.; Oswald, K.D.

1991-01-01

The Department of Energy - Morgantown Energy Technology Center and the Pennsylvania Energy Development Authority are co-funding a project which will demonstrate the reduction of infectious hospital waste to an environmentally safe disposable ash by cofiring the waste with coal in a circulating fluidized bed (CFB). The main objective of this paper is increased utilization of coal but the project also provides a solution to a problem which has grown rapidly and become very visible in recent years (e.g., hospital waste washed up on beaches). The application of CFB boilers in hospitals introduces an economical clean coal technology into a size range and market dominated by gas and oil combustion systems. The use of CFB represents the utilization of state-of-the-art technology for burning coal in an environmentally benign manner. SO 2 , NO x , CO and particulate emissions lower than the latest New Source Performance Standards have proven to be achievable in CFB combustion systems. By processing the infectious waste in a steam generation system which operates continuously, the problem of creating excessive gaseous emissions during repeated start-ups (as is the case with current incinerator technology) is avoided. The operating conditions with respect to residence time, temperature and turbulence that are inherent to a CFB combustion system, provide an excellent environment for complete combustion and destruction of potentially hazardous solid and gaseous emissions (e.g., dioxins). The limestone, which is injected into the combustion system to reduce SO 2 emissions, will also react with chlorine. Thus chlorine compound emissions and the corrosive nature of the flue gas are reduced. The work efforts to date indicate that infectious waste thermal processing in a coal-fired CFB is a technically and economically viable on-site disposal option

Demonstration of coal reburning for cyclone boiler NO{sub x} control. Appendix, Book 1

Energy Technology Data Exchange (ETDEWEB)

1994-06-01

Based on the industry need for a pilot-scale cyclone boiler simulator, Babcock Wilcox (B&W) designed, fabricated, and installed such a facility at its Alliance Research Center (ARC) in 1985. The project involved conversion of an existing pulverized coal-fired facility to be cyclone-firing capable. Additionally, convective section tube banks were installed in the upper furnace in order to simulate a typical boiler convection pass. The small boiler simulator (SBS) is designed to simulate most fireside aspects of full-size utility boilers such as combustion and flue gas emissions characteristics, fireside deposition, etc. Prior to the design of the pilot-scale cyclone boiler simulator, the various cyclone boiler types were reviewed in order to identify the inherent cyclone boiler design characteristics which are applicable to the majority of these boilers. The cyclone boiler characteristics that were reviewed include NO{sub x} emissions, furnace exit gas temperature (FEGT) carbon loss, and total furnace residence time. Previous pilot-scale cyclone-fired furnace experience identified the following concerns: (1) Operability of a small cyclone furnace (e.g., continuous slag tapping capability). (2) The optimum cyclone(s) configuration for the pilot-scale unit. (3) Compatibility of NO{sub x} levels, carbon burnout, cyclone ash carryover to the convection pass, cyclone temperature, furnace residence time, and FEGT.

Seasonal performance and energy costs of oil or gas-fired boilers and furnaces

Energy Technology Data Exchange (ETDEWEB)

Berlad, A.L.; Lin, H.C.; Batey, J.; Salzano, F.J.; Yu, W.S.; Hoppe, R.J.; Allen, T.

1977-03-01

The seasonal operating cost of a small oil or gas-fired boiler or furnace depends upon the intrinsic merits of the device itself, the appropriateness of its capacity and cycle characteristics to the imposed load conditions, the weather characteristics and heat loss characteristics of the building being heated, and the control philosophy employed. The current study provides the bases for comparing quantitatively the seasonal operating costs of various specific space heating and/or domestic hot water systems, as influenced by the device specifics and device interaction with the space conditioned system that it serves. The resulting formalism is applied to various space-heating systems. Quantitative cost comparisons are presented.

BARRIER ISSUES TO THE UTILIZATION OF BIOMASS

Energy Technology Data Exchange (ETDEWEB)

Bruce C. Folkedahl; Jay R. Gunderson; Darren D. Schmidt; Greg F. Weber; Christopher J. Zygarlicke

2002-09-01

The Energy & Environmental Research Center (EERC) has completed a project to examine fundamental issues that could limit the use of biomass in small industrial steam/power systems in order to increase the future use of this valuable domestic resource. Specifically, the EERC attempted to elucidate the ash-related problems--grate clinkering and heat exchange surface fouling--associated with cofiring coal and biomass in grate-fired systems. Utilization of biomass in stoker boilers designed for coal can be a cause of concern for boiler operators. Boilers that were designed for low-volatile fuels with lower reactivities can experience problematic fouling when switched to higher-volatile and more reactive coal-biomass blends. Higher heat release rates at the grate can cause increased clinkering or slagging at the grate due to higher temperatures. Combustion and loss of volatile matter can start much earlier for biomass fuels compared to design fuel, vaporizing alkali and chlorides which then condense on rear walls and heat exchange tube banks in the convective pass of the stoker, causing noticeable increases in fouling. In addition, stoker-fired boilers that switch to biomass blends may encounter new chemical species such as potassium sulfates, various chlorides, and phosphates. These species in combination with different flue gas temperatures, because of changes in fuel heating value, can adversely affect ash deposition behavior. The goal of this project was to identify the primary ash mechanisms related to grate clinkering and heat exchange surface fouling associated with cofiring coal and biomass--specifically wood and agricultural residuals--in grate-fired systems, leading to future mitigation of these problems. The specific technical objectives of the project were: (1) Modification of an existing pilot-scale combustion system to simulate a grate-fired system. (2) Verification testing of the simulator. (3) Laboratory-scale testing and fuel characterization to

BARRIER ISSUES TO THE UTILIZATION OF BIOMASS; SEMIANNUAL

International Nuclear Information System (INIS)

Bruce C. Folkedahl; Darren D. Schmidt; Greg F. Weber; Christopher J. Zygarlicke

2001-01-01

The Energy and Environmental Research Center (EERC) is conducting a project to examine the fundamental issues limiting the use of biomass in small industrial steam/power systems in order to increase the future use of this valuable domestic resource. Specifically, the EERC is attempting to elucidate the ash-related problems-grate clinkering and heat exchange surface fouling-associated with cofiring coal and biomass in grate-fired systems. Utilization of biomass in stoker boilers designed for coal can be a cause of concern for boiler operators. Boilers that were designed for low volatile fuels with lower reactivities can experience damaging fouling when switched to higher volatile and more reactive lower-rank fuels, such as when cofiring biomass. Higher heat release rates at the grate can cause more clinkering or slagging at the grate because of higher temperatures. Combustion and loss of volatile matter can start too early for biomass fuels compared to the design fuel, vaporizing alkali and chlorides which then condense on rear walls and heat exchange tube banks in the convective pass of the stoker, causing noticeable increases in fouling. In addition, stoker-fired boilers that switch to biomass blends may encounter new chemical species such as potassium sulfates and various chlorides, in combination with different flue gas temperatures because of changes in fuel heating value which can adversely affect ash deposition behavior. The goal of this project is to identify the primary ash mechanisms related to grate clinkering and heat exchange surface fouling associated with cofiring coal and biomass-specifically wood and agricultural residuals-in grate-fired systems, leading to future mitigation of these problems. The specific technical objectives of the project are: Modification of an existing EERC pilot-scale combustion system to simulate a grate-fired system; Verification testing of the simulator; Laboratory-scale testing and fuel characterization to determine ash

Measurement of gas species, temperatures, coal burnout, and wall heat fluxes in a 200 MWe lignite-fired boiler with different overfire air damper openings