- Email: [email protected]
01713 Flow injection thermal analysis-mass spectrometry: application to studies of carbon gasification reactions
16
Fuel science and technology (fundamental
science, analysis, instrumentation)
Development of coprecipitated nickel-alumina cat99iO1702 alyst for pyrocatalytic gasification of biomass
Garcia, L. et al. Biomass Energy Environ., Proc. Eur. Bioenergv Conf., 9th, 1996, 2, 1359-1364. Edited by Chartier, P., Elsevier, Oxford, UK. Studies concerning the catalytic pyrolysis of biomass in a continuous bench scale fluidized bed reactor at 650 and 700°C are reported. To obtain a high gas yield a crystallized nickel aluminate catalyst prepared by co-precipitation is used. The influence of the reaction temperature has been studied. The differences between the results obtained with and without a catalyst are analysed.
preheating yielded no such agreement, since data taken under transient conditions impair the results. Experimental design guidelines for making reactivity measurements on solid fuels in experimental reactors are given.
Experimental investigation of complex processing of brown coals
90io1709
Butkhareit, L. V. et al. Ugol’U/v. 1996, (9), 8-10. (In Russian) Discusses an experimental plant for complex processing of brown coal and oil shale. The plant includes installations for semi-coking, gas cooling, tar condensation, and tar dewatering.
9alo1703
Does microwave heating have a role in functional group reactions of coal?
9alo1710
Bodman, S. et al. Fuel, 1997, 76, (13), 1315-1318. The application of microwave heating to specific problems in coal science, in particular coal characterization, is briefly reviewed and new data on the removal of organic sulfur are also discussed. The technique can be invaluable in the laboratory for driving heterogeneous reactions involving coal, particularly when side-reactions are minimal. The steric demand of a reagent is an important factor to be considered, as is the accessibility and steric environment of the coal functional groups that are to be reacted. Research so far suggests that optimal conditions for the success of microwave-driven chemicals are achieved by use of silicon- and tincontaining reagents.
Bartusiak, R. et al. Journal of Petroleum Science and Engineering, 1997, 17, (l/2), 19-28. For a number of years, underbalanced perforating has been practised in order to minimize formation damage in and around the perforation tunnel. High transient flow rates are thought to sweep crushed rock and charge debris into the wellbore, leaving a clean tunnel. With sufficient underbalance, formation damage surrounding the tunnel is also reduced. In practice, the minimum underbalance and the volume of surge flow required per perforation become part of the completion design. Recent theoretical studies predict that most of this cleanup process occurs early in the transient flow process, suggesting that large transient flow volumes may not be needed. Using a modified standard test procedure from the American Petroleum Institute, transient flow rates into perforations in Berea Sandstone have been measured, varying underbalances and surge flow volume.
98/01704 catalysts
DRIFTS
studies
on Co/Ti02
Fischer-Tropsch
Mothebe, B. et al. Stud. Surf Sci. Caral., 1997, 107, 187-192. ‘ The paper gives details of a DRIFTS study of CO on Co/TiO2. Results reveal that highly reduced cobalt shows a strong v(C0) absorption at -2010 cm-’ while a partially reduced sample absorbs strongly at -2060 cm-‘. The effect of pressure and temperature on the spectra give predictable results. Thus, absorption intensity increases with pressure and v(C0) absorptions move to higher wavenumber with temperature, presumably due to surface oxidation through CO decomposition. Room temperature reduction by CO of preheated Co(NOs)z/TiOz was observed suggesting the facile nature of the surface Co reduction process. Water was found to oxidize reduced Co at 200°C. DRIFTS studies were also performed over the variously reduced Co/ Ti02 catalysts by reaction of the catalysts with CO/Hz. The more highly reduced catalyst produced higher hydrocarbon yields, as detected by v(CHI) and v(CH3) absorptions. 98/01705
Drying units for flotation wastes recovered from a
settler
Lobanov, A. V. et al. Ugol’Ukr., 1996, (12), 32-34. (In Russian) A pilot plant for drying and granulation of fine coal flotation waste from a settler reduces the moisture content from 28-30 to lo-12 wt% and gives a product containing 39.5% particles 3-6 mm and 40% >6 mm. This product can be used as fuel in coal beneficiation plants.
EFCC-a cycle power stations
98101706
future concept for coal-fired combined
Edelmann, H. and Stuhlmuller, F. VOB Kraftwerkstech., 1997, 77, (7), 537-543. (In German) The externally fired combined cycle (EFCC) concept is presented for coalfired power stations. With an indirect coal-fired ias turbine, the flue gas heat from slag-tap pulverized coal-firing was transferred in a hightemperature heat exchanger to a gas turbine operating regime. This concept achieves net efficiencies of up to 53% from gas turbines. The expected costs for such a plant correspond with those of combined cycle plants with pre-connected coal pressurized gasification. The paper presents demands on further development of the components for a EFCC plant.
Enhanced efficiency power unit operiting on coal :::i707 Vikhrev, Y. B. Energetik, 1997, (8), 22. (In Russian) A 385 MWt power unit, considered to be the most economical in Europe, is described. The unit is installed in the power plant Vestkraft (Esbjerg) [ELSAM system (Denmark)] and has been in operation for several years.
Evaluation shrinking-core models
96iO1700
of char reactivity data by, different
Sorensen, L. H. el al. Fuel, 1996, 75, (ll), 1294-1300. Two entrained flow reactors, two drop tube furnaces and one fluidized bed were used to measure carbon reactivity. The results were interpreted by using three shrinking-core models. A number of minor differences between the models were identified, and the resulting deviations could mostly be ascribed to non-measurable parameters such as particle specific heat capacity as a function of temperature, boundary layer gas composition and Nusselt and Sherwood numbers, together with bulk flow equations and numerical procedure. Using all experimental data, the calculations gave different overall activation energies ranging from 107 to 130 kJ/mol. Under realistic conditions for combustion and for the experiments performed, the differences between the model calculations with respect to overall kinetics were small but significant. A comparison between individual experiments showed that for experiments performed with small coal particles, long residence times or preheated particles, good agreement between model results was obtained. Larger particles, short residence time and no
148
Fuel and Energy Abstracts
March 1999
Experimental investigation of surge flow velocity and volume needed to obtain perforation cleanup
99lo1711 Experimental study on thermal balance in the gasifier with a twin-fluidized-beds Li, Z. et al. Ranshao Kexue Yu Jishu, 1996, 2, (l), 15-22. (In Chinese) The ignition and heating of a twin fluidized bed gasifier, the temperature profile of the twin bed and the heat transfer between the two beds were investigated in a middle scale hot-mode experimental apparatus. The solid particle circulating rate between the beds was calculated from the experimental results. Variables affecting the operation of the gasifier are analysed and a steady base was made for further study of coal gasification.
Experiments on contrail formation from fuels with different sulfur content
90lo1712
Busen, R. et al. Rep. Inst. Physical Atmos., 1996, 68, 5-10. The role of the sulfur contained in kerosene in contrail formation processes has been investigated with a series of tests and experimentation. The last SULFUR 4 experiment dealing with the influence of the fuel sulfur content and different conditions is described in detail: different sulfur mass fractions lead to different particle size spectra. The number of ice particles in the contrail increases by about a factor of 2 for 3000 ppm instead of 6 ppm sulfur fuel content.
Flow injection thermal analysis-mass spectrometv: application to studies of carbon gasification reactions
96101713
Jones, J. M. et al. Carbon, 1997, 35, (2), 217-225. Gasification reactions can be studied with flow injection combined with thermal analysis-mass spectrometry. This method provides a rapid, powerful method of separating the variables of a particular reaction, studying their influence on the reaction products and differential thermal analysis. The present work illustrates the technique using the following examples: (1) the reaction of NO with carbon, and (2) the reaction of NH3 and NO over carbon. In both cases, >99% isotopically pure 13C was used, so that Nz and CO, and also NzO and COz could be mass-resolved. The results illustrate the application of the technique to the study of the effect of oxygen concentration and gasification temperature on the formation of N20 and Nz during the NO-carbon reaction. It was revealed that N20:N2 ratio increases with oxygen concentration while increased temperature decreases the concentration of N20.
99lo1714
Flow velocity of jetsam in a vibrating fluidized bed
99lo1715 models
Fuuy
Jin, H. et al. Ranliao Huaxue Xuebao, 1997, 25, (5), 428432. (In Chinese) The paper presents the movement in a rectangular gas-solid vibrated fluidized bed which is characteristic of jetsam. The effects of vibration strength, vibration angle, bed slope angle on particle motion velocity were investigated. Based on the particle movement equation and the effects of vibration parameters, a theoretical movement velocity was obtained which agrees with the experimental movement velocity. According to the effects of vibration parameters and materials movement velocity on separation efficiency, optimum operating conditions were obtained which will significantly aid the design of an industrial coke-slag separation unit.
data compression for energy optimization
Groscurth, H.-M. and Kress, K.-P. Energy, 1998, 23, (l), l-9. Calculating energy savings and emission-reduction potentials for municipal energy systems requires computer models with high spatial and temporal disaggregation. Consequently, the computational effort necessary to run such models is considerable. For the optimization models ecco, ecco-solar and deeco, this problem has so far been solved by assuming that the time intervals considered are independent of each other and may, therefore, be
Fuel science and technology (fundamental
science, analysis, instrumentation)
Development of coprecipitated nickel-alumina cat99iO1702 alyst for pyrocatalytic gasification of biomass
Garcia, L. et al. Biomass Energy Environ., Proc. Eur. Bioenergv Conf., 9th, 1996, 2, 1359-1364. Edited by Chartier, P., Elsevier, Oxford, UK. Studies concerning the catalytic pyrolysis of biomass in a continuous bench scale fluidized bed reactor at 650 and 700°C are reported. To obtain a high gas yield a crystallized nickel aluminate catalyst prepared by co-precipitation is used. The influence of the reaction temperature has been studied. The differences between the results obtained with and without a catalyst are analysed.
preheating yielded no such agreement, since data taken under transient conditions impair the results. Experimental design guidelines for making reactivity measurements on solid fuels in experimental reactors are given.
Experimental investigation of complex processing of brown coals
90io1709
Butkhareit, L. V. et al. Ugol’U/v. 1996, (9), 8-10. (In Russian) Discusses an experimental plant for complex processing of brown coal and oil shale. The plant includes installations for semi-coking, gas cooling, tar condensation, and tar dewatering.
9alo1703
Does microwave heating have a role in functional group reactions of coal?
9alo1710
Bodman, S. et al. Fuel, 1997, 76, (13), 1315-1318. The application of microwave heating to specific problems in coal science, in particular coal characterization, is briefly reviewed and new data on the removal of organic sulfur are also discussed. The technique can be invaluable in the laboratory for driving heterogeneous reactions involving coal, particularly when side-reactions are minimal. The steric demand of a reagent is an important factor to be considered, as is the accessibility and steric environment of the coal functional groups that are to be reacted. Research so far suggests that optimal conditions for the success of microwave-driven chemicals are achieved by use of silicon- and tincontaining reagents.
Bartusiak, R. et al. Journal of Petroleum Science and Engineering, 1997, 17, (l/2), 19-28. For a number of years, underbalanced perforating has been practised in order to minimize formation damage in and around the perforation tunnel. High transient flow rates are thought to sweep crushed rock and charge debris into the wellbore, leaving a clean tunnel. With sufficient underbalance, formation damage surrounding the tunnel is also reduced. In practice, the minimum underbalance and the volume of surge flow required per perforation become part of the completion design. Recent theoretical studies predict that most of this cleanup process occurs early in the transient flow process, suggesting that large transient flow volumes may not be needed. Using a modified standard test procedure from the American Petroleum Institute, transient flow rates into perforations in Berea Sandstone have been measured, varying underbalances and surge flow volume.
98/01704 catalysts
DRIFTS
studies
on Co/Ti02
Fischer-Tropsch
Mothebe, B. et al. Stud. Surf Sci. Caral., 1997, 107, 187-192. ‘ The paper gives details of a DRIFTS study of CO on Co/TiO2. Results reveal that highly reduced cobalt shows a strong v(C0) absorption at -2010 cm-’ while a partially reduced sample absorbs strongly at -2060 cm-‘. The effect of pressure and temperature on the spectra give predictable results. Thus, absorption intensity increases with pressure and v(C0) absorptions move to higher wavenumber with temperature, presumably due to surface oxidation through CO decomposition. Room temperature reduction by CO of preheated Co(NOs)z/TiOz was observed suggesting the facile nature of the surface Co reduction process. Water was found to oxidize reduced Co at 200°C. DRIFTS studies were also performed over the variously reduced Co/ Ti02 catalysts by reaction of the catalysts with CO/Hz. The more highly reduced catalyst produced higher hydrocarbon yields, as detected by v(CHI) and v(CH3) absorptions. 98/01705
Drying units for flotation wastes recovered from a
settler
Lobanov, A. V. et al. Ugol’Ukr., 1996, (12), 32-34. (In Russian) A pilot plant for drying and granulation of fine coal flotation waste from a settler reduces the moisture content from 28-30 to lo-12 wt% and gives a product containing 39.5% particles 3-6 mm and 40% >6 mm. This product can be used as fuel in coal beneficiation plants.
EFCC-a cycle power stations
98101706
future concept for coal-fired combined
Edelmann, H. and Stuhlmuller, F. VOB Kraftwerkstech., 1997, 77, (7), 537-543. (In German) The externally fired combined cycle (EFCC) concept is presented for coalfired power stations. With an indirect coal-fired ias turbine, the flue gas heat from slag-tap pulverized coal-firing was transferred in a hightemperature heat exchanger to a gas turbine operating regime. This concept achieves net efficiencies of up to 53% from gas turbines. The expected costs for such a plant correspond with those of combined cycle plants with pre-connected coal pressurized gasification. The paper presents demands on further development of the components for a EFCC plant.
Enhanced efficiency power unit operiting on coal :::i707 Vikhrev, Y. B. Energetik, 1997, (8), 22. (In Russian) A 385 MWt power unit, considered to be the most economical in Europe, is described. The unit is installed in the power plant Vestkraft (Esbjerg) [ELSAM system (Denmark)] and has been in operation for several years.
Evaluation shrinking-core models
96iO1700
of char reactivity data by, different
Sorensen, L. H. el al. Fuel, 1996, 75, (ll), 1294-1300. Two entrained flow reactors, two drop tube furnaces and one fluidized bed were used to measure carbon reactivity. The results were interpreted by using three shrinking-core models. A number of minor differences between the models were identified, and the resulting deviations could mostly be ascribed to non-measurable parameters such as particle specific heat capacity as a function of temperature, boundary layer gas composition and Nusselt and Sherwood numbers, together with bulk flow equations and numerical procedure. Using all experimental data, the calculations gave different overall activation energies ranging from 107 to 130 kJ/mol. Under realistic conditions for combustion and for the experiments performed, the differences between the model calculations with respect to overall kinetics were small but significant. A comparison between individual experiments showed that for experiments performed with small coal particles, long residence times or preheated particles, good agreement between model results was obtained. Larger particles, short residence time and no
148
Fuel and Energy Abstracts
March 1999
Experimental investigation of surge flow velocity and volume needed to obtain perforation cleanup
99lo1711 Experimental study on thermal balance in the gasifier with a twin-fluidized-beds Li, Z. et al. Ranshao Kexue Yu Jishu, 1996, 2, (l), 15-22. (In Chinese) The ignition and heating of a twin fluidized bed gasifier, the temperature profile of the twin bed and the heat transfer between the two beds were investigated in a middle scale hot-mode experimental apparatus. The solid particle circulating rate between the beds was calculated from the experimental results. Variables affecting the operation of the gasifier are analysed and a steady base was made for further study of coal gasification.
Experiments on contrail formation from fuels with different sulfur content
90lo1712
Busen, R. et al. Rep. Inst. Physical Atmos., 1996, 68, 5-10. The role of the sulfur contained in kerosene in contrail formation processes has been investigated with a series of tests and experimentation. The last SULFUR 4 experiment dealing with the influence of the fuel sulfur content and different conditions is described in detail: different sulfur mass fractions lead to different particle size spectra. The number of ice particles in the contrail increases by about a factor of 2 for 3000 ppm instead of 6 ppm sulfur fuel content.
Flow injection thermal analysis-mass spectrometv: application to studies of carbon gasification reactions
96101713
Jones, J. M. et al. Carbon, 1997, 35, (2), 217-225. Gasification reactions can be studied with flow injection combined with thermal analysis-mass spectrometry. This method provides a rapid, powerful method of separating the variables of a particular reaction, studying their influence on the reaction products and differential thermal analysis. The present work illustrates the technique using the following examples: (1) the reaction of NO with carbon, and (2) the reaction of NH3 and NO over carbon. In both cases, >99% isotopically pure 13C was used, so that Nz and CO, and also NzO and COz could be mass-resolved. The results illustrate the application of the technique to the study of the effect of oxygen concentration and gasification temperature on the formation of N20 and Nz during the NO-carbon reaction. It was revealed that N20:N2 ratio increases with oxygen concentration while increased temperature decreases the concentration of N20.
99lo1714
Flow velocity of jetsam in a vibrating fluidized bed
99lo1715 models
Fuuy
Jin, H. et al. Ranliao Huaxue Xuebao, 1997, 25, (5), 428432. (In Chinese) The paper presents the movement in a rectangular gas-solid vibrated fluidized bed which is characteristic of jetsam. The effects of vibration strength, vibration angle, bed slope angle on particle motion velocity were investigated. Based on the particle movement equation and the effects of vibration parameters, a theoretical movement velocity was obtained which agrees with the experimental movement velocity. According to the effects of vibration parameters and materials movement velocity on separation efficiency, optimum operating conditions were obtained which will significantly aid the design of an industrial coke-slag separation unit.
data compression for energy optimization
Groscurth, H.-M. and Kress, K.-P. Energy, 1998, 23, (l), l-9. Calculating energy savings and emission-reduction potentials for municipal energy systems requires computer models with high spatial and temporal disaggregation. Consequently, the computational effort necessary to run such models is considerable. For the optimization models ecco, ecco-solar and deeco, this problem has so far been solved by assuming that the time intervals considered are independent of each other and may, therefore, be