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00729 Influence of granular carbons on pitch properties
04 By-products related to fuels Efficient generation of hydrogen is an important enabling technology for commercialization of fuel cells for homes and cars of the future. A methodology for optimization of an autothermal reactor with respect to system parameters is described. Furthermore, a framework for theoretical interpretation of reforming reactions is developed using an atomic balance approach, which is utilized to determine the reforming reaction space and maximum monolith temperature for a methane reformer.
04/00722 ruthenium
Partial oxidation of methane membrane reactor
in a catalytic
Paturzo, L. et al. Industrial & Engineering Chemistry Research, 2003, 42, (13), 2968-2974. A catalytic ruthenium membrane reactor (CRMR) is analysed with regard to the methane partial oxidation reaction for synthesis gas production. The catalytic membrane consists of a compound ceramic tube, where two different layers of ruthenium nanoparticles have been deposited on the inner surface. The metal deposition was performed by decomposition of a Ru complex under mild conditions. Different operating modes are analysed for CRMR to establish the potentiality of the Ru catalyst deposited on the tubular ceramic support. A comparison in terms of methane conversion at various temperatures is presented. Experimental runs of CRMR containing a one-Ru-layer membrane and a two-Ru-layer membrane have also been compared.
04/00723
Purification
of synthesis
gas
Bancon, S. and Le Bet, R. Fr. Demande FR 2832,141 (Cl. COlB3/56), 16 May 2003, Appl. 2001/14,710. (In French) The invention relates to a process of purification of synthesis gas of a CO/Ha or N2/Hz type which involves elimination of COz and possibly other gas impurities (e.g. HaO) before passage in a cryogenic process. The impurities are adsorbed by passage of the gas flow through a NaLSX-type zeolite bed; desorption is done in a regeneration stage which can be done by a temperature increase (thermal-swing adsorption) and/or by pressure decrease (pressure-swing adsorption or vacuum-swing adsorption).
04/00724 Steam gasification rapid heating
characteristics
Stepwise production of CO-rich syngas and via methane reforming by a WOB-redox catalyst
Kodama, T. et al. Energy, 2003, 28, (1 l), 1055-1068. A two-step cyclic steam reforming of methane by a WOs/ZrOz redox catalyst was performed to produce CO-rich syngas and hydrogen. The two-step cyclic processes could be repeated using a redox system of WOs below 1273 K. The produced CO-rich syngas had the Ha/CO ratios of about two, which was suitable for methanol production. This endothermic syngas-production process will be used as a solar thermochemical process for converting concentrated solar radiation to chemical liquid fuel of methanol in the sun-belt regions. The solar syngas-production process using the WOs/ZrOz catalyst was demonstrated in a laboratory scale under direct irradiation of the catalyst by a solar-simulated, high-flux visible light.
04iOO726 Synthesis gas production state reactor network
in a forced
unsteady
Fissore, D. et al. Industrial & Engineering Chemistry Research, 2003, 42, (12), 2489-2495. The feasibility of producing synthesis gas by the combination of partial oxidation and seam reforming of natural gas on a Pt-based catalyst in forced unsteady-state catalytic reactors was considered by numerical simulations. A network of three reactors with periodical change of the feed position was investigated as an alternative to the well-investigated reverse-flow reactor: these modes of reactor operation may lead to lower syngas manufacturing costs than the conventional unidirectional 96
Fuel
and
Energy
Abstracts
March 2004
04100727 Zinc oxide sorbents sulfide from syngas
for the removal
of hydrogen
ROSSO, I. et al. Industrial t Engineering Chemistry Research, 2003, 42, (8), 1688-1697. Several pure zinc oxide materials, prepared with different methods (combustion synthesis and a modified version of the citrates method) and calcined at different temperatures, were investigated as lowtemperature desulfurizing sorbents from gaseous streams (syngas, in particular). Comparative tests with a sorbent were also carried out. The sulfidation performance was investigated in a fixed-bed reactor in terms of breakthrough curves at 250”. Fresh and sulfided samples were characterized by X-ray diffraction. SEM-energy dispersion spectroscopy, BET, pore volume, pore size, and pore size distribution analyses. The ZnO sorhent prepared by the titrated method calcined at 400” showed the most durable effectiveness in reducing sulfur from 100 to < 1 ppm: its breakthrough time is ~9 h measured at a space velocity of ~10 hIts regeneration ability was evaluated by subsequent sulfidation-thermal regeneration cycles. A numerical model was also developed and validated on the experimental data of the ZnO sorbent calcined at 400” a good agreement was obtained. The internal masstransfer resistance resulted in the rate-limiting step of the process. Sulfur sorption was confined to the external layers of the pellets (because it was difficult for HzS to reach the adsorbent core), and a maximization of internal open porosity to improve the system performance was pointed out as the main route for further developments and improvements.
of coal with
Fushimi, C. et al. Journal of Analytical and Applied Pyrolysis, 2003, 70, (2), 185-197. Time profiles of weight change of coal samples and the evolution of low molecular weight gases (Ha, CH4, CO and COz) in both steam gasification and pyrolysis of Yallourn brown coal and Taiheiyo subbituminous coal were measured using a thermo-balance reactor with a micro GC and a mass spectrometer, in order to examine the reaction mechanism of steam gasification with rapid heating (100 K s-l). It was found that, in the case of slow heating, steam reacted with metaplast and promoted the evolution of tar above 623 K and that a water shift reaction took place above 873 K. Steam gasification of produced char occurred above 1023 K, increasing the evolution of CO, COz and Hz. When the heating rate was high, steam reforming of volatile matter and steam gasification of metaplast took place parallel to metaplast formation and condensation. The char produced by pyrolysis was almost completely gasified and converted into Ha and COz by steam. The chemical energy of coal was mainly converted into hydrogen energy and the gasification efficiency was slightly increased by rapid heating (i.e. 100 K s-l).
04100725 hydrogen
fixed-bed reactor because external heat exchangers are no longer required. A cyclic steady-state condition and autothermal behaviour can be obtained by feeding low-temperature reactants. The influence of the main operating parameters (inlet temperature, switching time, inlet flow rate, and composition) on the performance of the device was investigated, proving that the network can be competitive with traditional technologies, allowing for higher reactant conversion and product selectivity. The possibility of tailoring the Ha/CO ratio to the value required for the production of methanol or Fischer-Tropsch synthesis was addressed.
04 BY-PRODUCTS RELATED TO FUELS 04/00728 A low-voltage carbon particles
spark generator
for production
of
Horvath, H. and Gang], M. Journal of Aerosol Science, 2003, 34, (1 l), 1581-1588. A spark of short duration between two carbon electrodes produces carbon vapour which immediately condenses and forms carbon particles of about 30 nm size. The spark is obtained by discharging a capacitor triggered by a small high-frequency spark by means of a Tesla transformer. Thus the initiation of the spark and the discharge are decoupled. Both the distance of the electrodes, the energy of the discharge and the frequency of the sparks can be varied independently. Furthermore it is possible to charge the capacitor to voltages of only -100 V for the discharge. A very stable and continuous operation of the generator has been achieved for tens of hours, particles sizes between 10 and 100 nm can be produced.
04100729
influence
of granular
carbons
on pitch properties
Mendez, A. et al. Fuel, 2003, 82, (lo), 1241-1250. This paper deals with the study of the variation of properties of four pitches (a commercial impregnating coal tar pitch, an air-blown and two thermally treated pitches) when mixed with four granular carbons (anthracite, graphite, green petroleum coke and foundry coke). As a first step, optical microscopy was used to determine the distribution of the pitch among the granular carbons. The anthracite seems to attract the primary quinoline insolubles present in the commercial and thermally treated pitches. This allows the mesophase spheres to coalesce at unusually low temperatures during the mixing process. In general, the toluene insoluble content of the pitch showed a significant increase after mixing with the granular carbons. This is an indication of the interactions between the different granular carbons and some compounds present in the pitches. Analytical techniques like size exclusion chromatography and differential scanning calorimetric analysis were used in order to obtain information about the characteristics of the components of the pitches that interact with the different granular carbons and their effect on pitch properties. Graphite seems to interact preferentially with the larger molecules whereas the green petroleum coke acts on a wider molecular range.
04/00722 ruthenium
Partial oxidation of methane membrane reactor
in a catalytic
Paturzo, L. et al. Industrial & Engineering Chemistry Research, 2003, 42, (13), 2968-2974. A catalytic ruthenium membrane reactor (CRMR) is analysed with regard to the methane partial oxidation reaction for synthesis gas production. The catalytic membrane consists of a compound ceramic tube, where two different layers of ruthenium nanoparticles have been deposited on the inner surface. The metal deposition was performed by decomposition of a Ru complex under mild conditions. Different operating modes are analysed for CRMR to establish the potentiality of the Ru catalyst deposited on the tubular ceramic support. A comparison in terms of methane conversion at various temperatures is presented. Experimental runs of CRMR containing a one-Ru-layer membrane and a two-Ru-layer membrane have also been compared.
04/00723
Purification
of synthesis
gas
Bancon, S. and Le Bet, R. Fr. Demande FR 2832,141 (Cl. COlB3/56), 16 May 2003, Appl. 2001/14,710. (In French) The invention relates to a process of purification of synthesis gas of a CO/Ha or N2/Hz type which involves elimination of COz and possibly other gas impurities (e.g. HaO) before passage in a cryogenic process. The impurities are adsorbed by passage of the gas flow through a NaLSX-type zeolite bed; desorption is done in a regeneration stage which can be done by a temperature increase (thermal-swing adsorption) and/or by pressure decrease (pressure-swing adsorption or vacuum-swing adsorption).
04/00724 Steam gasification rapid heating
characteristics
Stepwise production of CO-rich syngas and via methane reforming by a WOB-redox catalyst
Kodama, T. et al. Energy, 2003, 28, (1 l), 1055-1068. A two-step cyclic steam reforming of methane by a WOs/ZrOz redox catalyst was performed to produce CO-rich syngas and hydrogen. The two-step cyclic processes could be repeated using a redox system of WOs below 1273 K. The produced CO-rich syngas had the Ha/CO ratios of about two, which was suitable for methanol production. This endothermic syngas-production process will be used as a solar thermochemical process for converting concentrated solar radiation to chemical liquid fuel of methanol in the sun-belt regions. The solar syngas-production process using the WOs/ZrOz catalyst was demonstrated in a laboratory scale under direct irradiation of the catalyst by a solar-simulated, high-flux visible light.
04iOO726 Synthesis gas production state reactor network
in a forced
unsteady
Fissore, D. et al. Industrial & Engineering Chemistry Research, 2003, 42, (12), 2489-2495. The feasibility of producing synthesis gas by the combination of partial oxidation and seam reforming of natural gas on a Pt-based catalyst in forced unsteady-state catalytic reactors was considered by numerical simulations. A network of three reactors with periodical change of the feed position was investigated as an alternative to the well-investigated reverse-flow reactor: these modes of reactor operation may lead to lower syngas manufacturing costs than the conventional unidirectional 96
Fuel
and
Energy
Abstracts
March 2004
04100727 Zinc oxide sorbents sulfide from syngas
for the removal
of hydrogen
ROSSO, I. et al. Industrial t Engineering Chemistry Research, 2003, 42, (8), 1688-1697. Several pure zinc oxide materials, prepared with different methods (combustion synthesis and a modified version of the citrates method) and calcined at different temperatures, were investigated as lowtemperature desulfurizing sorbents from gaseous streams (syngas, in particular). Comparative tests with a sorbent were also carried out. The sulfidation performance was investigated in a fixed-bed reactor in terms of breakthrough curves at 250”. Fresh and sulfided samples were characterized by X-ray diffraction. SEM-energy dispersion spectroscopy, BET, pore volume, pore size, and pore size distribution analyses. The ZnO sorhent prepared by the titrated method calcined at 400” showed the most durable effectiveness in reducing sulfur from 100 to < 1 ppm: its breakthrough time is ~9 h measured at a space velocity of ~10 hIts regeneration ability was evaluated by subsequent sulfidation-thermal regeneration cycles. A numerical model was also developed and validated on the experimental data of the ZnO sorbent calcined at 400” a good agreement was obtained. The internal masstransfer resistance resulted in the rate-limiting step of the process. Sulfur sorption was confined to the external layers of the pellets (because it was difficult for HzS to reach the adsorbent core), and a maximization of internal open porosity to improve the system performance was pointed out as the main route for further developments and improvements.
of coal with
Fushimi, C. et al. Journal of Analytical and Applied Pyrolysis, 2003, 70, (2), 185-197. Time profiles of weight change of coal samples and the evolution of low molecular weight gases (Ha, CH4, CO and COz) in both steam gasification and pyrolysis of Yallourn brown coal and Taiheiyo subbituminous coal were measured using a thermo-balance reactor with a micro GC and a mass spectrometer, in order to examine the reaction mechanism of steam gasification with rapid heating (100 K s-l). It was found that, in the case of slow heating, steam reacted with metaplast and promoted the evolution of tar above 623 K and that a water shift reaction took place above 873 K. Steam gasification of produced char occurred above 1023 K, increasing the evolution of CO, COz and Hz. When the heating rate was high, steam reforming of volatile matter and steam gasification of metaplast took place parallel to metaplast formation and condensation. The char produced by pyrolysis was almost completely gasified and converted into Ha and COz by steam. The chemical energy of coal was mainly converted into hydrogen energy and the gasification efficiency was slightly increased by rapid heating (i.e. 100 K s-l).
04100725 hydrogen
fixed-bed reactor because external heat exchangers are no longer required. A cyclic steady-state condition and autothermal behaviour can be obtained by feeding low-temperature reactants. The influence of the main operating parameters (inlet temperature, switching time, inlet flow rate, and composition) on the performance of the device was investigated, proving that the network can be competitive with traditional technologies, allowing for higher reactant conversion and product selectivity. The possibility of tailoring the Ha/CO ratio to the value required for the production of methanol or Fischer-Tropsch synthesis was addressed.
04 BY-PRODUCTS RELATED TO FUELS 04/00728 A low-voltage carbon particles
spark generator
for production
of
Horvath, H. and Gang], M. Journal of Aerosol Science, 2003, 34, (1 l), 1581-1588. A spark of short duration between two carbon electrodes produces carbon vapour which immediately condenses and forms carbon particles of about 30 nm size. The spark is obtained by discharging a capacitor triggered by a small high-frequency spark by means of a Tesla transformer. Thus the initiation of the spark and the discharge are decoupled. Both the distance of the electrodes, the energy of the discharge and the frequency of the sparks can be varied independently. Furthermore it is possible to charge the capacitor to voltages of only -100 V for the discharge. A very stable and continuous operation of the generator has been achieved for tens of hours, particles sizes between 10 and 100 nm can be produced.
04100729
influence
of granular
carbons
on pitch properties
Mendez, A. et al. Fuel, 2003, 82, (lo), 1241-1250. This paper deals with the study of the variation of properties of four pitches (a commercial impregnating coal tar pitch, an air-blown and two thermally treated pitches) when mixed with four granular carbons (anthracite, graphite, green petroleum coke and foundry coke). As a first step, optical microscopy was used to determine the distribution of the pitch among the granular carbons. The anthracite seems to attract the primary quinoline insolubles present in the commercial and thermally treated pitches. This allows the mesophase spheres to coalesce at unusually low temperatures during the mixing process. In general, the toluene insoluble content of the pitch showed a significant increase after mixing with the granular carbons. This is an indication of the interactions between the different granular carbons and some compounds present in the pitches. Analytical techniques like size exclusion chromatography and differential scanning calorimetric analysis were used in order to obtain information about the characteristics of the components of the pitches that interact with the different granular carbons and their effect on pitch properties. Graphite seems to interact preferentially with the larger molecules whereas the green petroleum coke acts on a wider molecular range.