Combustion (burners, combustion systems)
96/02922 Retrofitting of Jaenschwalde power station with 3000 MW of electric power based on nitrogen oxide free combustion technology with extensive adherence to the original plant configuration Peter, R. et al., VGBKraftwerkstech., 1995, 75, (9), 805-813. (In German) The steam boiler at the lignite-fired Jaenschwalde power plant in East Germanywas converted in 1991 and recommissioned.The foundation for a successful trial was established by comprehensive measures such as air and fuel gradation, air volume decrease, fuel concentration, and vapour separation. Also a comprehensive boiler and combustion equipment refurbishment programme was undertaken leading to good operating results.
Weld repair of steam drum downcomer nozzle cracking in coal-fired power plant Allen, D. 1. Weld. Met. Fabr., 1995, 63, (6), 225-228. Describes the weld repair recently carried out by PowerGen to a cracked steam drum downcomer nozzle weld in a coal-fired 500MW unit at Cottam Power Station. It illustrates how a major on-site repair may be implemented, including the application of specialized weld repair techniques.
09 COMBUSTION Burners, Combustion Systems 96/02924
Analyzer of unburned coal-dust fuel In the boiler units of thermal power plants Tarasevich, V. N. Elektr. Stn., 1995, (8), 6-13. (In French) The author describes an analyzer for the determination of carbon in fly ash. The method is based on gasification of the ash carbon, followed by thermochemical measurement of CO concentration in gasification products.
Appliance ventilation ducts for room-sealed appliances Baumann, P. et al., Gaz d'aujourd'hui, Jan. 1996, 120, (I), 7-14. (In French) The penetration of natural gas into the multi-family market has always been a preoccupation for Gaz de France. As far as independant heating is concerned, professions involved in the building industry are well acquainted with the advantages of room-sealed appliances. Balanced flued appliances with horizontal flue terminals have been on the market for several years now, and recently, balanced flued appliances with flue terminal projecting above the roof have also appeared on the market. All that was missing from this range was an appliance ventilation duct. The problem has now been solved. This duct is now on the market. The article, after a general introduction to this new system, presents the technical characteristics of three products currently available in France.
96/02926 Assessment of turbulent combustion submodels using linear eddy model Desjardin, P. E. and Frankel, S. H. Combustion & Flame, Feb. 1996, 104, (3), 343-357. Linear eddy model simulations are conducted in order to study turbulencechemistry interactions in a homogeneous, incompressible,stationary turbulent flow with non-premixed reactants. The chemical kinetics model used in this work involves single- and multi-step, reversible and irreversible isothermal reactions. The simulation results are employed to investigate the flame structure and statistics and comparisons are made to several other turbulent combustion models. 96/02927
Asymptotic and numerical study of diffusion flames with variable Lewis number and finite rate chemistry Cuenot, B. and Poinsot, T. Combustion & Flame, Jan. 1996, 104, (1), 111-137. The authors used an an asymptotic method to derive analytical expressions for the profiles of all thermodynamic and chemical quantities of diffusion flame with variable density, nonuniform Lewis number and finite rate chemistry, and for different configurations (unsteady unstrained, steady strained and unsteady strained flames). The accuracy of the results are checked using numerical simulations with the same chemical and transport models. The results are then used to quantify the effects of finite rate chemistry and different Lewis numbers on the flame structure.
96/02928 Burning velocities, Markstein lengths, and flame quenching for spherical methane-aIr flames: A computational study Bradley, D. et al., Combustion & Flame, Jan. 1996, 104, (1), 176-198. Computations are for three modes of spherical laminar flame propagation: explosion, implosion and stationary. The reduced kinetic C" scheme of Mauss and Peters is employed for a range of equivalence ratios under atmospheric conditions, with flame propagation at constant pressure. Save for the richest mixtures, the scheme is fully adequate for present purposes. Two burning velocities are computed, one based on the rate of disapperance of unburned gas, the other on the rate of appearance of burned gas.
Fuel and Energy Abstracts May 1996
The characteristics of pulverized coal combustion in 02/C02 mixtures for CO2 recovery Kimura, N. et al., Energy Converso Mgmt., Juri-Sep. 1995, 36, (6), 805-808. O/CO z blown combustion is a promising technique in the technology of recovering COz from flue gases generated by coal-fired power plants. The fuel in such a system is burned in an Oz/COz mixture instead of air, raising the COz concentration in the flue gas to about 95%. In order to determine the characteristics of pulverized coal combustion in the O/CO z mixture, the authors conducted a benchscale test using a 1.2-MWt tunnel furnace with a coal feed rate of 150 kg/h. This project is proceeding as part of a national project and financial supported by New Energy and Industrial Technology Development Organization (NEDP), Japan.
Chemical kinetic modeling of N2 formation and decomposition during coal combustion Yuan, J. and Feng, B. Huazhong Ligong Daxue Xuebao, 1995, 23, (4), 114-119. (In Chinese) Presents a chemical kinetic modelling of NzO formation and decomposition during the combustion of a single coal particle and volatiles in the freeboard of a fluidized bed combustor.
Chemical structures of fuel-rich flames of transC2H2CI2/CHJAr/0 2 mixtures Castaldi, M. 1. and Senkan, S. M. Combustion & Flame, Jan. 1996, 104, (1),41-50. Temperature and species concentration profiles were obtained for atmospheric-pressure, premixed, laminar, flat flames of trans-CzHzClz/CH4 mixtures under fuel-rich conditions at several Cl/H ratios.
96/02932 Circulating fluld-bed reactor for coal pyrolysis Sciazko, M. and Zielinski, H. Chem. Eng. Technol., 1995, 18, (5), 343-348. Describes a high-temperaturecoal pyrolysis reactor which has been developed and demonstrated at a scale of 8 tons/h. The process, which was considered a partial coal gasification system, was carried out in a circulating fluidized bed at 850-950° and integrated into a demonstration plant for manufacture of briquetted smokeless fuel. 96/02933
Coal combustion under conditions of blast furnace injection Crelling, J. C. Proc. lronmaking Conf., 1995, 73-79. Based on computer modelling results, lower-rank bituminous coal (including coal from the Illinois Basin) compare well in their injection properties with a variety of other bituminous coals, although the replacement ratio improves with increasing rank. Based on petrography analyses of material collected from an active blast furnace, it is clear that a coal-derived semicoke actually enters the raceway of the blast furnace. Results indicate that the semicokes from the lower-rank coals should have a superior burnout rate in the tuyere and should survive in the raceway environment for a shorter time.
Coal particle surface characteristics and the surface smoothness factor in theory of combustion Gu, F. et al., Yingyong Kexue Xuebao, 1995, 13, (2), 127-135. (In Chinese) Discusses the relationship between coal combustion and the particle surface smoothness factor which was established by energy pattern analysis. A measurement system consisting of an ESM and an image computer was developed and used.
96/02935 Coke oven gas combustion systems Cheng, C. L. Nengyuan Jikan, 1995,25, (3), 181-188. (In Chinese) Discusses how staged air concept is used to design a coke oven gas combustor with efficient control of NO, formation. 96/02936 Combined combustion of biomass, municipal sewage sludge and coal in an atmospheric fluidized bed installation Van Doorn, 1. et al., ECN-C Report ECN-C-95-096, 1995, 34 pp. The cofiring of biomass or sewage sludge with coal in a fluidized-bed installation influences the combustion behaviour and the flue gas emissions. In the case of coal/wood co-combustion the concentrates of NO" S02 and CO in the flue gas were lower compared with coal-firing. No operational problems were observed with co-firing wood and coal. In the case of straw and sewage sludge agglomeration of the bed material occurred; adaptations of the combustion conditions are necessary for commercial application. 96/02937
Combustion mechanism of pulverized coal injected into blast furnace and its simulation Sato, M. et al., Rev. Metall./Cah. In! Tech., 1995, 92, (3), 343-349. In order to understand the behaviour of pulverized coal injected into blast furnaces, direct observation of the combustion using high-speed camera was used. It was found that the combustion flame of pulverized coat was not uniform across the cross-section in blowpipe and tuyere. It was found that the flow pattern of pulverized coal particles governed by injection lance arrangement had a significant effect on combustibility.