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06292 Combustion characteristics of low-rank bituminous coal
OS Burning vrlocitles and flammability Ilmltr of gasr95/09299 ous mixtures at olrvated temperatures and pressures Shebeko, Y. N. er al., Combustion & Flame, Sep. 1995, 102, (4), 427.437. Burning velocities and flammability limits of gaseous mixtures of combustible gas (hydrogen and meth ), oxidizer (oxygen and air), and diluent ? dioxide. steam. water aerosol formed bv (nitronen. arson. helium. carbo &ooratibn Ef s;nerhea&d water) has bein mea&red at elevated temoera’tures (up to 2505 and pressures’(up to 4.0 MPa). It was found thatrwith increasin tern erature, the flammability region is widened for all the mixtures stuAed. &’Ith increasing pressure, the flammable region for mixtures of hydrogen-oxygen-diluent is narrowed, except where steam or water aerosol is the diluent. A more complicated dependence of flammability limit on pressure is found for mixtures of hydrogen-oxygen-steam. The influence of water aerosol on the flammability limits of methane in air was also investigated. Calcium sulfide formatlon In fluldlzrd bed boilers 95/05290 L ngfelt, A. et al., Can. J. Chem. Eng., 1995, 73, (2), 228-233. e oaoer describes the analvsis of sainoles of bed ash from combustion in d a &&nary fluidized-bed bbiler whicd showed the resence of calcium sulphide. In some of the samples half of the total suPphur was present as sulphide. Changes of propertles and structure of coking SW6291 coals durlng the coking process Jaazho, S. et al., Karbo-Energochem.-Ekol., 19?4,39, (7), 155-162. (In
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Discusses the changes of the physicochemical properties and structure of gas- and gas-coking coals during coking at 300-1500” by X-ray spectroscopy and microscopy. Combustion characteristics of low-rank bltumlSW6292 nous coal Xue, Y. Meitan Zhuanhuq 1995, 18, (l), 531-56.(In Chinese) Discusses studies of the combustion of four low-rank bituminous coals by thermogravimetric analysis.
Combustion (burners, combustion systems)
Comparisons of the soot volume fraction using and light rxtlnctlon techniques . . . Combustion & Flame, Jul. 1995, 102, (l), 161-169. Simultaneous optical and gravimetric measurements were oerformed in the postflame region of an acetylene/air premixed flame wherithe temperature of the soot/gas mixture was reduced to 500 K through nitrogen dilution. By combining gravimetric measurements of the collected soot with soot densit measurements using helium pycnometry, an accurate value of the soot voTume fraction was obtained. 95106299 rhzln$t;
95lo63tm Convective mass transport In a coke oven Klose,W. andNowack,G. Fuel, Sep. 1995, 74, (9), 1369-1374. The 2D convective mass transport mechanism is modelled in a coke oven. Solving the non-steady state energy balance, the local reaction rate of the volatile mattr is calculated by formal kinetics equations for each time steo. The permeability of the c&l charge (equation’of Ergun), of the plas& layer (transwrt model bv diiersion of bubbles) and of the semi-coke laver (fiow‘throigh rough fi-ssur&) is introduced ‘m a non-linear, anistroiic parameter. The total reactor charge is divided into seven zones accordmg to the property function of the charge. In each of these zones, the mass balance is solved. The pressures and the mass flow vectors in the whole charge are presented. 95/05301 Corrosion and erosion Rademakers, P. L. Coal Sci. Technol., 1995. 22. 139-184. A review of corrosion and erosior). 95106302 Detailed klnetlc modeling of C,-C, slkane diffusion flames Leung, K. M. and Lindstedt, R. P. Combustion & Flame, Jul. 1995, 102, (l), 129-160. A study of detailed chemical kinetics in coflow and counterflow diffusion flames is presented. The chemistry of diffusion flames is of fundamental importance from a practical as well as a mechanistic viewpoint. The present study uses systematic reaction path flux and sensitivity analyses lo fatrep the crucial reaction paths in methane and propane diffusion
Combustion of CWM droplets. 2. Estimation of 95106293 mass changes of flying droplets Iki, N. et al., Nivvon Kikai Gakkai Ronbunshy B-hen, 1995, 61, (581). 311-316. (In Japan&e) Describes the combustion of flying coal-water kixture droplets in an electric furnace to obtain basic data on the mass changes of coal-water mixture spray. The calculation mode for the mass reduction of a single coal-water mixture droplet was based on the experimental results on mass changes and combustion periods in the combustion of a suspended droplet.
95106303 Development potential of lignite-fired power statlon technology Bergmann, H. and Bauer, F. VGB Kraffwerkstech., 1995, 75, (2), 134-140. (In German) Discusses the potential efficiency increases of German power generation plants on the basis of brown coal with reference to present technologies with short-term potential for improvements to efficiencies of 43% and 48% for the period following the year 2010, and long-term options allowing efficiencies of ~60%.
Combustion of Imported coal In combined heat and 95lQ6294 power generstion plants Zehner. P. VGB Krafhuerkstech.. 1995. 75. (31. 231-242. (In German1 Discusses the deposits-and reserves of biium&;b c,oal, its &lid fuel cobposition, emissions of combustion gases, utilization of ash and flue gas desulphurization gypsum, and the combustion process.
95106304 Dlagnosls and llfe predlctlon for aging coke oven plants Garin, J. et al., Proc. Ironmaking Co@, 1994, (53), 37-43. The authors discusses how over the last ten years, we have been able to gain a better understanding of the degridation mechanisms and to set up a system for monitoring and evaluating the condition of the ovens, based on constant observations and measurements. This has enabled them to characterize changes in the condition of the batteries in a qualitative and meaningful manner. The various inspections are carried out using a rigorous working method, under codified conditions. This makes it possible lo compare the data for the various batteries.
Combustion of single coal particles 95106296 Pehlivan, D. et al., Turk. J.Eng. Environ. Sci., 1995, 19, (l), 3.5-41. Describes how by using a vertical heated chamber, combustion rate and time measurements were undertaken for single particles, of 1.7-13 mm size range of Zonguldak bituminous coal and Cizre and Tuncbilek lignites at 973 K starting temperature. Power law models were confirmed for both volatiles and char combustion times. Comment on ‘Lamlnar burning velocities and Mark95106296 stein numbers of hydrocarbon/air flames’ by L.-K. Tseng, MA. Ismall, and GM. Faeth ~;~$5S. C. and Smith, D. B. Combustion & Flame, Sep. i995, 102, (4).
Droplet lgnltlon and combustion lncludlng Ilquld95/06305 phase heating s_h;Jgan, N. and Prakash, S. Combusfian & Flame, Jul. 1995, 102, (l),
Commercisl development of advanced PFBC 95106297 technology McClung. J. D. Prevr. Pav.-Am. Chem. SOL Div. Fuel Chem., 1995.40. (2), 308311. . . Describes the commercialization of advanced pressurized fluidized-bed combustion technology. Discusses conceptual design, pilot-scale component testing, integrated system testing, and demonstration.
Heating, ignition, and the subsequent combustion of a liquid droplet are studied in a hot stagnant environment. The transient, coupled liquid-gas phase problem of droplet combustion in one dimension is solved numerically. The pressure is assumed lo be uniform and constant. This assumption is utilized in a novel way to formulate and solve the continuity equation. It is found that ignition occurs as soon as suitable conditions develop in the neighbourhood of the droplet. In fact, the droplet surface heating is intimately connected with ignition. These general conclusions are found to be true for a volatile n-heptane) as well as for a less volatile fuel (n-hexadecane). It is also zound that the radial velocity produced by the evaporation and combustion of the droplet, leads to a local Reynolds number of order one. Convective effects are as important as diffusional effects.
Comparison of Pdf and eddy-dissipation combus95106296 tion models applied to a propane jet flame Lau, J. H. Combustion & Flame, Jul. 1995, 102, (l), 209-2 5. A sample calculation of a turbulent jet flame was performed a*smg a finite volume method and a coupled finite volume-pdf method with a four-step reduced reaction scheme. The results demonstrate that the adopted kinetic mechanism gives a good general representation of the flame, but the CO, CO , and NO concentrations are predicted more accurately when the pdf meth od is incorporated. The models for convection and turbulent diffusion of the notional particles give acceptable results and there does not appear to be any inherent difficulty in extending the calculation procedure to general combustor flows with recirculation.
95106306 The effect of hosphorus chemistry on recomblnation losses in a superson Pc nozzle Twarowski, A. Combustion & Flame, Jul. 1995, 102, (l), 55-63. In previous articles, phosphine combustion products were-shown to catalyze H + OH recombination in equilibrium relaxation experiments. In this work, calculations of heat release and specific impulse- are reported for combustion products expanding at supersonic velocities in a nozzle. The calculations use a reaction set with 11 phosophorus-containing reactions. The addition of several percent by mass phosphine to hydrogen fuel substantially increases the heat release per unit fuel mass calculated for the nozzle. A gain in specific impulse is calculated for fuel-rich combustion of hydrogen fuel with phosphine added.
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Fuel and Energy Abstracts November 1995 445
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Discusses the changes of the physicochemical properties and structure of gas- and gas-coking coals during coking at 300-1500” by X-ray spectroscopy and microscopy. Combustion characteristics of low-rank bltumlSW6292 nous coal Xue, Y. Meitan Zhuanhuq 1995, 18, (l), 531-56.(In Chinese) Discusses studies of the combustion of four low-rank bituminous coals by thermogravimetric analysis.
Combustion (burners, combustion systems)
Comparisons of the soot volume fraction using and light rxtlnctlon techniques . . . Combustion & Flame, Jul. 1995, 102, (l), 161-169. Simultaneous optical and gravimetric measurements were oerformed in the postflame region of an acetylene/air premixed flame wherithe temperature of the soot/gas mixture was reduced to 500 K through nitrogen dilution. By combining gravimetric measurements of the collected soot with soot densit measurements using helium pycnometry, an accurate value of the soot voTume fraction was obtained. 95106299 rhzln$t;
95lo63tm Convective mass transport In a coke oven Klose,W. andNowack,G. Fuel, Sep. 1995, 74, (9), 1369-1374. The 2D convective mass transport mechanism is modelled in a coke oven. Solving the non-steady state energy balance, the local reaction rate of the volatile mattr is calculated by formal kinetics equations for each time steo. The permeability of the c&l charge (equation’of Ergun), of the plas& layer (transwrt model bv diiersion of bubbles) and of the semi-coke laver (fiow‘throigh rough fi-ssur&) is introduced ‘m a non-linear, anistroiic parameter. The total reactor charge is divided into seven zones accordmg to the property function of the charge. In each of these zones, the mass balance is solved. The pressures and the mass flow vectors in the whole charge are presented. 95/05301 Corrosion and erosion Rademakers, P. L. Coal Sci. Technol., 1995. 22. 139-184. A review of corrosion and erosior). 95106302 Detailed klnetlc modeling of C,-C, slkane diffusion flames Leung, K. M. and Lindstedt, R. P. Combustion & Flame, Jul. 1995, 102, (l), 129-160. A study of detailed chemical kinetics in coflow and counterflow diffusion flames is presented. The chemistry of diffusion flames is of fundamental importance from a practical as well as a mechanistic viewpoint. The present study uses systematic reaction path flux and sensitivity analyses lo fatrep the crucial reaction paths in methane and propane diffusion
Combustion of CWM droplets. 2. Estimation of 95106293 mass changes of flying droplets Iki, N. et al., Nivvon Kikai Gakkai Ronbunshy B-hen, 1995, 61, (581). 311-316. (In Japan&e) Describes the combustion of flying coal-water kixture droplets in an electric furnace to obtain basic data on the mass changes of coal-water mixture spray. The calculation mode for the mass reduction of a single coal-water mixture droplet was based on the experimental results on mass changes and combustion periods in the combustion of a suspended droplet.
95106303 Development potential of lignite-fired power statlon technology Bergmann, H. and Bauer, F. VGB Kraffwerkstech., 1995, 75, (2), 134-140. (In German) Discusses the potential efficiency increases of German power generation plants on the basis of brown coal with reference to present technologies with short-term potential for improvements to efficiencies of 43% and 48% for the period following the year 2010, and long-term options allowing efficiencies of ~60%.
Combustion of Imported coal In combined heat and 95lQ6294 power generstion plants Zehner. P. VGB Krafhuerkstech.. 1995. 75. (31. 231-242. (In German1 Discusses the deposits-and reserves of biium&;b c,oal, its &lid fuel cobposition, emissions of combustion gases, utilization of ash and flue gas desulphurization gypsum, and the combustion process.
95106304 Dlagnosls and llfe predlctlon for aging coke oven plants Garin, J. et al., Proc. Ironmaking Co@, 1994, (53), 37-43. The authors discusses how over the last ten years, we have been able to gain a better understanding of the degridation mechanisms and to set up a system for monitoring and evaluating the condition of the ovens, based on constant observations and measurements. This has enabled them to characterize changes in the condition of the batteries in a qualitative and meaningful manner. The various inspections are carried out using a rigorous working method, under codified conditions. This makes it possible lo compare the data for the various batteries.
Combustion of single coal particles 95106296 Pehlivan, D. et al., Turk. J.Eng. Environ. Sci., 1995, 19, (l), 3.5-41. Describes how by using a vertical heated chamber, combustion rate and time measurements were undertaken for single particles, of 1.7-13 mm size range of Zonguldak bituminous coal and Cizre and Tuncbilek lignites at 973 K starting temperature. Power law models were confirmed for both volatiles and char combustion times. Comment on ‘Lamlnar burning velocities and Mark95106296 stein numbers of hydrocarbon/air flames’ by L.-K. Tseng, MA. Ismall, and GM. Faeth ~;~$5S. C. and Smith, D. B. Combustion & Flame, Sep. i995, 102, (4).
Droplet lgnltlon and combustion lncludlng Ilquld95/06305 phase heating s_h;Jgan, N. and Prakash, S. Combusfian & Flame, Jul. 1995, 102, (l),
Commercisl development of advanced PFBC 95106297 technology McClung. J. D. Prevr. Pav.-Am. Chem. SOL Div. Fuel Chem., 1995.40. (2), 308311. . . Describes the commercialization of advanced pressurized fluidized-bed combustion technology. Discusses conceptual design, pilot-scale component testing, integrated system testing, and demonstration.
Heating, ignition, and the subsequent combustion of a liquid droplet are studied in a hot stagnant environment. The transient, coupled liquid-gas phase problem of droplet combustion in one dimension is solved numerically. The pressure is assumed lo be uniform and constant. This assumption is utilized in a novel way to formulate and solve the continuity equation. It is found that ignition occurs as soon as suitable conditions develop in the neighbourhood of the droplet. In fact, the droplet surface heating is intimately connected with ignition. These general conclusions are found to be true for a volatile n-heptane) as well as for a less volatile fuel (n-hexadecane). It is also zound that the radial velocity produced by the evaporation and combustion of the droplet, leads to a local Reynolds number of order one. Convective effects are as important as diffusional effects.
Comparison of Pdf and eddy-dissipation combus95106296 tion models applied to a propane jet flame Lau, J. H. Combustion & Flame, Jul. 1995, 102, (l), 209-2 5. A sample calculation of a turbulent jet flame was performed a*smg a finite volume method and a coupled finite volume-pdf method with a four-step reduced reaction scheme. The results demonstrate that the adopted kinetic mechanism gives a good general representation of the flame, but the CO, CO , and NO concentrations are predicted more accurately when the pdf meth od is incorporated. The models for convection and turbulent diffusion of the notional particles give acceptable results and there does not appear to be any inherent difficulty in extending the calculation procedure to general combustor flows with recirculation.
95106306 The effect of hosphorus chemistry on recomblnation losses in a superson Pc nozzle Twarowski, A. Combustion & Flame, Jul. 1995, 102, (l), 55-63. In previous articles, phosphine combustion products were-shown to catalyze H + OH recombination in equilibrium relaxation experiments. In this work, calculations of heat release and specific impulse- are reported for combustion products expanding at supersonic velocities in a nozzle. The calculations use a reaction set with 11 phosophorus-containing reactions. The addition of several percent by mass phosphine to hydrogen fuel substantially increases the heat release per unit fuel mass calculated for the nozzle. A gain in specific impulse is calculated for fuel-rich combustion of hydrogen fuel with phosphine added.
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.
Fuel and Energy Abstracts November 1995 445