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02043 Cyclopenta-fused polycyclic aromatic hydrocarbons from brown coal pyrolysis
09 Combustion
00/02040
Coal combustion: pyrolysis and oxidation
Daco, A. Riv. Conthusr.. 1998. 52. (4). 165-189. (In Italian) Approximately 50% of the world’s energy supply is provided by coal combustion. Detailed research has been conducted in order to understand the combustion phenomena. The theoretical concepts of coal pyrolysis and char oxidation are examined. In addition, the principal and simplest kinetic models useful for evaluating different coals are provided. Concerning NO, emission, few concepts on nitrogen evolution during coal combustion have been included, which would allow methods for emissions reduction to be examined.
00/02041 Combustion kinetics and NO and SO1 emission behavior of coke pellet mixed with iimelllmestone Lee, M. S. T&rrrrt Krrntsol; Ho/~+oec,hi, 1998. 36. (II). 1849-1858. (In Korean) This oaner reoorts on exoeriments oerformed to investieate the combustion of coke pellet mixed wiih lime and limestone. The mayn areas focused on were the combustion kinetics and NO and SOz emission behaviour between 700°C and 1300°C under a pure oxygen atmosphere. Intrinsic rate constants for the combustion of carbon. nitroeen. and sulfur were obtained from thermogravimetry and gas analysis data. The amounts of SO2 reduced by lime were virtually 99% below 1100°C and decreased to about 75% at 1300°C. Limestone as a sorbent for SOz was found to be superior to lime because the calcined lime was more active in reaction with SOI than lime. Pelletizing coke with lime/limestone had negligible effect on reducing the amounts of NO emitted during combustion of coke pellet in the experimental ranges. The combustion kinetics of coke pellkt mixed with lime/limestone and that of coke in a pellet composed of pure coke and the measurements were very similar.
00/02042
Combustion research in Kobe steel plant
Suzuki, T. Ner~sho Kenkrrc. 1999. I 15.69-76. (In Japanese) This review reports on combustion research in the Kobe steel plant. The study included coal combustion technology, heat storage regenerative burners, reduction of NO, emission and a fluidized-bed waste incinerator.
Cyclopenta-fused polycyclic aromatlc hydrocarbons from brown coal pyrolysis
(burners, combustion
systems)
formation). In comparison to a baseline case without reburning, the rate of carbon burnout was found to be higher with 20 cm of primary fuel injection, but proceeded very slowly through the reburning zone. At the end of the reactor, burnout was more complete in the baseline case. From the results it was apparent that the species, temperature. and solid sample elemental concentrations were self-consistent and should provide accurate data when comparing with modelling results. 00102045 Effect of coal moisture on particulate emission in a fixed bed combustion appliance Erdol, N. Fat,/ Procc~r. Tcc,/rrto/.. 1999. 5X. (2 ~3). 109 I I7 This investieation is concerned with the effect of moisture on oarticulate emissions of a young peaty (Agacli) coal from Turkey. The study was performed in a 93 kW, half cyclindrical hot water boiler. The boiler was operated under primary and secondary loading conditions. Sampling was realised using an EPA-approved Andersen Universal Sampling system. Experiments were conducted for 15.33%. 21.40% and 38.70% moisture coals of Agacli and 19.90% moisture Agacli-South African mixture coals. In conclusion, it was seen that the highest particulate emissions occurred from the medium moisture coals.
Effects of mineral matter on products and sulfur distributions in hydropyrolysis
00102046
Chen, H. Frrel. 1999. 78. (6). 71.1.-719. A fixed-bed reactor was used to investigate the effects of the mineral matter on the product yield and sulfur distribution in hydropyrolysis and pyrolysis of Chinese Hongmiao lignite. The volatile sulfur-containing gases (H$, COS, CHJH) were also analysed as a function of pyrolysis temperature. Coal samoles were treated with HCliHF or HCliHF mixed with CrCI, solution to eliminate minerals and pyrite respectively. During the hydropyrolysis of demineralized Hongmiao lignne, lower yields of tar and water’were produced than from raw-coal. Demineralizaiion cannot only minimize the fixation effect of basic mineral matter on sulfur-containing gases, but also increase the sulfur distribution of the tar. In addition it is possible to elucidate the contribution of minerals. pyrite and organic sulfur. to the evolution profiles of sulfur-containing gases.
00/02043
Wornat, M. J. S.wp. ffnf.) Conthust.. [Proc.], 1999 27th. 2, 1677-1686. In order to examine certain aspects of coal tar composition, acid-washed Yallourn brown coal was pyrolysed under nitrogen at temperatures of 6001000°C in a fluidized-bed reactor. Analysis of the product tar with reversephase high-performance liquid chromatography with diode-array UVvisible absorption detection, reveals that the tars are composed primarily of polycyclic aromatic compounds, many of which are polycyclic aromatic hydrocarbons (PAH) with peripherally fused cyclopenta rings (CP-PAH). Of the PAH. CP-PAH are of oarticular interest because thev are orone to oxidizing in the environment, ihey have a relatively high biojogica] activity and a postulated role in soot formation. Of the 10 CP-PAH identified in our tar samples, four of the most abundant are acenaphthylene (CtzHk). acephenanthrylene and aceanthrylene (C,,,H,,,), and cyclopental[cd]pyrene (CrsH,,,) - all of which have been detected previously in products of coal pyrolysis and/or combustion. The recent synthesis of several new CP-PAH reference standards, however, has enabled us to also identify, in the brown coal tars, six additional CP-PAH-cyclopent[hi]acephenanthrylene and cyclopenta(cd]fluoranthene (CrsH,,,), dicyclopenta(cd,mn]pyrene and dicyclopenta[cdjk]pyrene (Cz,,Ht,,). benzo[ghi]cyclopenta[cd]perylene (CzdHrz), and cyclopenta(bc]coronene (CzhHIZ) - none of which has ever before been identified in coal products. The mass fractions of individual CP-PAH span a range of four orders of magnitude - from 0.000062 for cyclopenta[bc]coronene to 0.265 for acenaohthvlene in the 1000°C tar sample. The CP-PAHs account for approximately one-third of the mass of the tar produced at 1000°C. The CP-PAH yields show a monotonic increase with pyrolysis temperature, thus confirming that the CP-PAH are not primary products of coai devolatilization but result instead from secondary pyrolytic reactions that occur in the gas phase. A study into possible reaction mechnanisms is also explored.
Detailed measurements in a pulverized coal flame with natural gas reburning
00102044
Nazeer, W. A. Ftrel. 1999. 78, (6). 689-699. Gas compositions and temperature profiles were measured inside a 200 kW, entrained flow, pulverized coal controlled profile reactor. Samples of NO, CO. CO,. NO_. 0, and NH, were collected with a water-cooled and waterquenched stainless steel probe and analysed on a dry basis with online gas analvsers and an ion-sensitive electrode (NH1) over a grid of 36 locations within the reactor. Temperature data were obtained with a suction avrometer usine an S-tvoe shielded thermocouple. An investigation was r,~ ~~ also carried out”into nitrogen oxide reduction with reburning, over a range of residence times and reburning zone stoichiometric ratios to optimize for maximum nitrogen oxide reduction in the flue gases. A decrease in stoichiometric ratio of the reburning zone resulted in an increase in NO reduction uo to a maximum of 79% at a stoichiometric ratio of 0.78. The tertiary air’injector was moved up and down axially, thus varying the residence time in the reburning zone. It was initially beneficial to increase the residence time in the reburning zone. but became unimportant when residence time became longer than 700 ms. The location of the reburning zone was found to be optimal when reburning fuel was directed at the location of highest NO concentration (i.e., immediately following NO
Efficient power generation with Holter’s integrated coal-waste system
00102047
Grabenhorst, U. Aufhcrcir. Tech.. 1999. 40. (4). 181.-1X2.1X4. The coal-waste combustion system is a prime example of how conventional power generation can be combined effectively with the disposal of waste. A grate-firing installation that operates as a satellite parallel to a power station steam generator can convert the chemical energy of municipal waste into thermal energy in the form of hot flue gas. This flue gas was introduced as substitute to coal, into the lower section of the steam generator and supplied some of the necessary thermal energy. A series of economic and ecological advantages were offered by the applrcation of this process.
00102048 Experimental studies on municipal solid waste pyrolysis in a laboratory-scale rotary kiln Li, A. M. E~n,rg.r. 1999. 24. (3). X9-2 IX. An externally heated, rotary-kiln pyrolyser, designed to he used in the laboratory has been constructed. Pyrolysis tests were carried out. Solid wastes (paper, wood, waste plastics including PVC and PE, paperboard, rubber, vegetal materials and orange husk) were experimentally studied. An evaluation of the effects of moisture contents. heating methods and size of waste on the gas yields and compositions from pyrolysis
Fast high temperature reactions of gas/solids suspensions in a downflow tube reactor
00102049
Geier, R. VGE Twh. b’er. Grosvkro/iwd .vherr., / Tq~m,cy/w. 1 I’GB-TB. 1998. A3/1-A3/10. At the Federal lnsitute of Technology in Zurich. Switzerland. experiments were conducted in a downflow tube reactor to assess coal flash pyrolysis. The reaction behaviour of single oarticles. oarticle ezelomerates and strands could be compared in the experimental cnvestigatityn. The operating conditions chosen were typical for both circulating fluidized bed and pulverized fuel combustion.. An analysis was also performed on the solid and gaseous products. An electron microscope was used to investigate the structural changes of the solid matter. It was shown that the solids loading ratio and local solids volume concentration that are known to have considerable influence on the homogeneity of a gas/solids suspension also has an influence on heat and mass transfer during flash pyrolysis. 00102050 Flash hvdroovrolvsls of coal - effect of coal ranks Gu, H. Huut/orr~z Li,&g D;rke ~rwhtro. 1999. 25. (1). I I 14. (in Chinese) In a small. entrained reactor at 750” under atmospheric hydrogen. 14 kinds of Chinese coal, with volatile components ranging from Y.XI% to 44.274, were flash hydropyrolysed. From the results, it is apparent that, there are close correlations between the carbon content of coal and the yields of liquid hydrocarbons, the H/C of coal and the yields of gas hydrocarbons, and the oxygen content of coal and the yields of CO, CO? and HzO. The characteristic values of coal for flash hydropyrolysis are H/C of 0.6 and carbon content of 85%. The coal, of which H/C is lower than 0.6 and carbon content is higher than 85%. ,is usually not suitable for flash hydropyrolysis. It has been discovered that, the influence of coal rank on yields of liquid as well as gas, and total conversion of coal in flash hydropyrolysis can he
Fuel and Energy Abstracts
July 2000
227
00/02040
Coal combustion: pyrolysis and oxidation
Daco, A. Riv. Conthusr.. 1998. 52. (4). 165-189. (In Italian) Approximately 50% of the world’s energy supply is provided by coal combustion. Detailed research has been conducted in order to understand the combustion phenomena. The theoretical concepts of coal pyrolysis and char oxidation are examined. In addition, the principal and simplest kinetic models useful for evaluating different coals are provided. Concerning NO, emission, few concepts on nitrogen evolution during coal combustion have been included, which would allow methods for emissions reduction to be examined.
00/02041 Combustion kinetics and NO and SO1 emission behavior of coke pellet mixed with iimelllmestone Lee, M. S. T&rrrrt Krrntsol; Ho/~+oec,hi, 1998. 36. (II). 1849-1858. (In Korean) This oaner reoorts on exoeriments oerformed to investieate the combustion of coke pellet mixed wiih lime and limestone. The mayn areas focused on were the combustion kinetics and NO and SOz emission behaviour between 700°C and 1300°C under a pure oxygen atmosphere. Intrinsic rate constants for the combustion of carbon. nitroeen. and sulfur were obtained from thermogravimetry and gas analysis data. The amounts of SO2 reduced by lime were virtually 99% below 1100°C and decreased to about 75% at 1300°C. Limestone as a sorbent for SOz was found to be superior to lime because the calcined lime was more active in reaction with SOI than lime. Pelletizing coke with lime/limestone had negligible effect on reducing the amounts of NO emitted during combustion of coke pellet in the experimental ranges. The combustion kinetics of coke pellkt mixed with lime/limestone and that of coke in a pellet composed of pure coke and the measurements were very similar.
00/02042
Combustion research in Kobe steel plant
Suzuki, T. Ner~sho Kenkrrc. 1999. I 15.69-76. (In Japanese) This review reports on combustion research in the Kobe steel plant. The study included coal combustion technology, heat storage regenerative burners, reduction of NO, emission and a fluidized-bed waste incinerator.
Cyclopenta-fused polycyclic aromatlc hydrocarbons from brown coal pyrolysis
(burners, combustion
systems)
formation). In comparison to a baseline case without reburning, the rate of carbon burnout was found to be higher with 20 cm of primary fuel injection, but proceeded very slowly through the reburning zone. At the end of the reactor, burnout was more complete in the baseline case. From the results it was apparent that the species, temperature. and solid sample elemental concentrations were self-consistent and should provide accurate data when comparing with modelling results. 00102045 Effect of coal moisture on particulate emission in a fixed bed combustion appliance Erdol, N. Fat,/ Procc~r. Tcc,/rrto/.. 1999. 5X. (2 ~3). 109 I I7 This investieation is concerned with the effect of moisture on oarticulate emissions of a young peaty (Agacli) coal from Turkey. The study was performed in a 93 kW, half cyclindrical hot water boiler. The boiler was operated under primary and secondary loading conditions. Sampling was realised using an EPA-approved Andersen Universal Sampling system. Experiments were conducted for 15.33%. 21.40% and 38.70% moisture coals of Agacli and 19.90% moisture Agacli-South African mixture coals. In conclusion, it was seen that the highest particulate emissions occurred from the medium moisture coals.
Effects of mineral matter on products and sulfur distributions in hydropyrolysis
00102046
Chen, H. Frrel. 1999. 78. (6). 71.1.-719. A fixed-bed reactor was used to investigate the effects of the mineral matter on the product yield and sulfur distribution in hydropyrolysis and pyrolysis of Chinese Hongmiao lignite. The volatile sulfur-containing gases (H$, COS, CHJH) were also analysed as a function of pyrolysis temperature. Coal samoles were treated with HCliHF or HCliHF mixed with CrCI, solution to eliminate minerals and pyrite respectively. During the hydropyrolysis of demineralized Hongmiao lignne, lower yields of tar and water’were produced than from raw-coal. Demineralizaiion cannot only minimize the fixation effect of basic mineral matter on sulfur-containing gases, but also increase the sulfur distribution of the tar. In addition it is possible to elucidate the contribution of minerals. pyrite and organic sulfur. to the evolution profiles of sulfur-containing gases.
00/02043
Wornat, M. J. S.wp. ffnf.) Conthust.. [Proc.], 1999 27th. 2, 1677-1686. In order to examine certain aspects of coal tar composition, acid-washed Yallourn brown coal was pyrolysed under nitrogen at temperatures of 6001000°C in a fluidized-bed reactor. Analysis of the product tar with reversephase high-performance liquid chromatography with diode-array UVvisible absorption detection, reveals that the tars are composed primarily of polycyclic aromatic compounds, many of which are polycyclic aromatic hydrocarbons (PAH) with peripherally fused cyclopenta rings (CP-PAH). Of the PAH. CP-PAH are of oarticular interest because thev are orone to oxidizing in the environment, ihey have a relatively high biojogica] activity and a postulated role in soot formation. Of the 10 CP-PAH identified in our tar samples, four of the most abundant are acenaphthylene (CtzHk). acephenanthrylene and aceanthrylene (C,,,H,,,), and cyclopental[cd]pyrene (CrsH,,,) - all of which have been detected previously in products of coal pyrolysis and/or combustion. The recent synthesis of several new CP-PAH reference standards, however, has enabled us to also identify, in the brown coal tars, six additional CP-PAH-cyclopent[hi]acephenanthrylene and cyclopenta(cd]fluoranthene (CrsH,,,), dicyclopenta(cd,mn]pyrene and dicyclopenta[cdjk]pyrene (Cz,,Ht,,). benzo[ghi]cyclopenta[cd]perylene (CzdHrz), and cyclopenta(bc]coronene (CzhHIZ) - none of which has ever before been identified in coal products. The mass fractions of individual CP-PAH span a range of four orders of magnitude - from 0.000062 for cyclopenta[bc]coronene to 0.265 for acenaohthvlene in the 1000°C tar sample. The CP-PAHs account for approximately one-third of the mass of the tar produced at 1000°C. The CP-PAH yields show a monotonic increase with pyrolysis temperature, thus confirming that the CP-PAH are not primary products of coai devolatilization but result instead from secondary pyrolytic reactions that occur in the gas phase. A study into possible reaction mechnanisms is also explored.
Detailed measurements in a pulverized coal flame with natural gas reburning
00102044
Nazeer, W. A. Ftrel. 1999. 78, (6). 689-699. Gas compositions and temperature profiles were measured inside a 200 kW, entrained flow, pulverized coal controlled profile reactor. Samples of NO, CO. CO,. NO_. 0, and NH, were collected with a water-cooled and waterquenched stainless steel probe and analysed on a dry basis with online gas analvsers and an ion-sensitive electrode (NH1) over a grid of 36 locations within the reactor. Temperature data were obtained with a suction avrometer usine an S-tvoe shielded thermocouple. An investigation was r,~ ~~ also carried out”into nitrogen oxide reduction with reburning, over a range of residence times and reburning zone stoichiometric ratios to optimize for maximum nitrogen oxide reduction in the flue gases. A decrease in stoichiometric ratio of the reburning zone resulted in an increase in NO reduction uo to a maximum of 79% at a stoichiometric ratio of 0.78. The tertiary air’injector was moved up and down axially, thus varying the residence time in the reburning zone. It was initially beneficial to increase the residence time in the reburning zone. but became unimportant when residence time became longer than 700 ms. The location of the reburning zone was found to be optimal when reburning fuel was directed at the location of highest NO concentration (i.e., immediately following NO
Efficient power generation with Holter’s integrated coal-waste system
00102047
Grabenhorst, U. Aufhcrcir. Tech.. 1999. 40. (4). 181.-1X2.1X4. The coal-waste combustion system is a prime example of how conventional power generation can be combined effectively with the disposal of waste. A grate-firing installation that operates as a satellite parallel to a power station steam generator can convert the chemical energy of municipal waste into thermal energy in the form of hot flue gas. This flue gas was introduced as substitute to coal, into the lower section of the steam generator and supplied some of the necessary thermal energy. A series of economic and ecological advantages were offered by the applrcation of this process.
00102048 Experimental studies on municipal solid waste pyrolysis in a laboratory-scale rotary kiln Li, A. M. E~n,rg.r. 1999. 24. (3). X9-2 IX. An externally heated, rotary-kiln pyrolyser, designed to he used in the laboratory has been constructed. Pyrolysis tests were carried out. Solid wastes (paper, wood, waste plastics including PVC and PE, paperboard, rubber, vegetal materials and orange husk) were experimentally studied. An evaluation of the effects of moisture contents. heating methods and size of waste on the gas yields and compositions from pyrolysis
Fast high temperature reactions of gas/solids suspensions in a downflow tube reactor
00102049
Geier, R. VGE Twh. b’er. Grosvkro/iwd .vherr., / Tq~m,cy/w. 1 I’GB-TB. 1998. A3/1-A3/10. At the Federal lnsitute of Technology in Zurich. Switzerland. experiments were conducted in a downflow tube reactor to assess coal flash pyrolysis. The reaction behaviour of single oarticles. oarticle ezelomerates and strands could be compared in the experimental cnvestigatityn. The operating conditions chosen were typical for both circulating fluidized bed and pulverized fuel combustion.. An analysis was also performed on the solid and gaseous products. An electron microscope was used to investigate the structural changes of the solid matter. It was shown that the solids loading ratio and local solids volume concentration that are known to have considerable influence on the homogeneity of a gas/solids suspension also has an influence on heat and mass transfer during flash pyrolysis. 00102050 Flash hvdroovrolvsls of coal - effect of coal ranks Gu, H. Huut/orr~z Li,&g D;rke ~rwhtro. 1999. 25. (1). I I 14. (in Chinese) In a small. entrained reactor at 750” under atmospheric hydrogen. 14 kinds of Chinese coal, with volatile components ranging from Y.XI% to 44.274, were flash hydropyrolysed. From the results, it is apparent that, there are close correlations between the carbon content of coal and the yields of liquid hydrocarbons, the H/C of coal and the yields of gas hydrocarbons, and the oxygen content of coal and the yields of CO, CO? and HzO. The characteristic values of coal for flash hydropyrolysis are H/C of 0.6 and carbon content of 85%. The coal, of which H/C is lower than 0.6 and carbon content is higher than 85%. ,is usually not suitable for flash hydropyrolysis. It has been discovered that, the influence of coal rank on yields of liquid as well as gas, and total conversion of coal in flash hydropyrolysis can he
Fuel and Energy Abstracts
July 2000
227