03110 Effect of impurities on desulfurization properties of limestone during coal gasification

03110 Effect of impurities on desulfurization properties of limestone during coal gasification

03 Gaseous fuels (derived gaseous fuels) Distributed injection process and apparatus for 99103 108 producing synthesis gas Hershkowitz, F. ef al. ...

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Distributed injection process and apparatus for 99103 108 producing synthesis gas Hershkowitz, F. ef al. PCT Int. Appl. WO 98 49,091 (Cl. COlB3/36), 5 Nov 1998, US Appl. 845,707, 25 Apr 1997, 42 pp. The paper discloses a novel injection reactor apparatus and an efficient process for partial oxidation of light hydrocarbon gases to convert such gases to useful synthesis gas for recovery and/or subsequent hydrocarbon synthesis. Sources comprising a light hydrocarbon gas and Oz or an oxygencontaining gas, preheated and pressurized, are injected through an injector means at high velocity into an admixture with each other in the desired relative proportions. Contacted with mixing nozzles which are open to the partial oxidation zone of a reactor and are uniformly-spaced over the face of the injector means, the sources form a reactant gaseous premix having a pressure 23% lower than the lowest upstream pressure of either of the streams of the individual gases. The gaseous premix is injected in a time period which is less than its auto-ignition time, preferably <9 ms, at a velocity of 25-1000 ft/s, into the partial oxidation zone of the reactor. The gas mixture reacts before or simultaneously with the auto-ignition time delay of the mixture, to reduce the amounts of COz, Hz0 and heat produced by the partial oxidation reaction to form a useful syngas which is cooled and recovered. 99103109 Durability of metal filters in low sulfur gasification gas conditions Nieminen, M. et al. High Temp. Gas Clean., [Pap. ht. Symp. Elrhib. Gas Clean. High Temp./ 3, 1996, 120-131. Edited by Schmidt, E., Institut fuer Mechanische Verfanrenstechnik und Mechanik der Universitaet Karlsruhe (TH), Karlsruhe, Germany Porous sintered metal filters, the subject of this paper, are a possible alternative for ceramic filter elements in fuel gas filtratton of low-sulfur gases, like biomass-derived gasification gas. The main potential advantages achievable by metal filters are good handling, mounting and sealing properties and durability to withstand thermo-mechanical shocks and stresses caused by system vibration. However, gaseous corrosion, mainly by sulfidation, is thought to limit the durability of metal filters in highly reducing, high-temperature and sulfur-bearing gasification atmospheres. The corrosion tendency of four commercial available metal filter materials was tested by carrying out long-term corrosion/durability tests with filter disks. The long-term corrosion tests showed that commercially available stainless steel filters (AISI 310 and AISI 316) can resist corrosion in lowsulfur gasification gas conditions at 400-500°C. The tests were carried out in simulated gas atmospheres on a controlled and reasonable level of HzS but without dust. Results were preliminary verified in realistic process conditions by carrying out a gasification and filtration test with metal filters. However, in long-term use in real gasification conditions other gas impurities, particularly HCI, may lead to corrosion problems when highchlorine fuels are gasified. 99lO3110 Effect of impurities on desulfurization properties of limestone during coal gasification Chang, L. et al. J. Environ. Sci., 1998, 10, (4). 485-490. A series of tests using three different limestones, four kinds of different sodium salts and four kinds different chlorides were conducted by X-ray diffraction and XPS techniques. This was undertaken in order to understand the function of calcium-based sorbents on desulfurization during coal gasification and the effect of impurities on it. The structure of precursory compounds and pre-treatment materials were examined by XRD. The binding energy and relative contents of sulfur, calcium and carbon, which exist in different forms in the residues after coal gasification, were measured by means of XPS. The existing forms of sulfur and calcium vary with impurities in limestone. Sodium or chloride play a promotive role on limestone desulfurization, but this promotion is affected by the chemical environment. 99103111 Effect of silica on iron-based Fischer-Tropsch catalysts Jothimurugesan, K. et al. Stud. Sutf Sci. Catal., 1998, 119, (Natural Gas Conversion V), 215-220. The authors investigated the effect of silica addition via co-precipitation and as a binder to a doubly promoted Fischer-Tropsch (F-T) synthesis iron catalyst (100 Fe/S Cu/4.2 K). The catalysts were prepared by coprecipitation, followed by binder addition and spray drying at 250°C in a 1 m diameter, 2 m tall spray dryer. The binder silica content was varied from 0 to 20 wt%. The highest attrition resistance was found with a catalyst containing 12 wt% binder silica. F-T reaction studies over 100 h in a fiiedbed reactor showed that this catalyst maintained around 95% CO conversion with a methane selectivity of less than 7 wt% and a Cs+ selectivity of greater than 73 wt%. The effect of adding precipitated silica from 0 to 20 parts by weight to this catalyst was also studied. Addition of precipitated silica was found to be detrimental to attrition resistance and resulted in increased methane and reduced wax formation. 99103112 Gas purifying device for fossil fuel gasificationpower generation systems Amaike, A. Jpn. Kokai Tokkyo Koho JP 10 287,885 [98 287,885] (Cl. ClOJ3/20), 27 Ott 1998, Appl. 97/98,930, 16 Apr 1997, 8 pp. (In Japanese) Using a raw gas, obtained by partial oxidation of a fossil fuel in a gasifier, a heat exchanger is used as the heat source. The apparatus also includes a water scrubber for the raw gas exiting the heat exchanger, a means for


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sulfur removal from the scrubbed gas by a dry process after it has been reheated in the heat exchanger and a means for removing dust from the sulfur-removed gas by a dry process. 99103113 Horizontal cylindric cartridge evaporator for hightemperature gas in coal gasification Tsumida, Y. Jpn. Kokai Tokkyo Koho JP IO 300,001 [98 300,001] (Cl. F22B1/18), 13 Nov 1998, Appl. 97/105,669,23 Apr 1997,4 pp. (In Japanese) In the evaporator, a pair of ring-shaped end pipes divide two end sections horizontally and there is a ring-shaped middle pipe with smaller diameter than that of the end pipe, annularly arranged in the central section. Several horizontal pipes and heat-transfer plates connected to the horizontal pipes are included. The evaporator improves stable two-phase flow and is especially suitable for use in the crossover duct between the gas coolers in coal gasification. 99103114 In situ characterization of cobalt based FischerTropsch catalysts: a new approach to the active phase Ducreux, 0. et al. Stud. Surf Sci. Catal., 1998, 119, (Natural Gas Conversion V), 125-130. A close correlation between structure modification and activity in in-situ characterization of cobalt based (Co/SiOz, Co/AlzOs and Co-Ru/TiOz) Fischer-Tropsch catalysts has been observed. Under Fischer-Tropsch reaction conditions cobalt and carbon monoxide can react to form a carbide (Co&), which is related with a deactivation process. 99103115 Influence of precursors on formation of a trimetallic defined structure. Application on Ni catalysts used for syngas obtention Provendier, H. et al. Stud. Surf Sci. Catal., 1998, 118, (Preparation of Catalysts VII), 285-294. For use as catalyst for the manufacture of syngas by methane reforming, a sol-gel preparation of trimetallic perovskites lanthanum-nickel-iron was studied. IR spectroscopic studies showed that the formation of the perovskite mixture, or nickel oxide deposited on LaFeOs as shown by Xray diffraction, depends on the nature of precursors. These structures are active in the partial oxidation of methane to synthesis gas. However, a significant effect of starting materials used in catalyst preparation on steam reforming of methane was observed. The advantage of defined structures in preventing the carbon formation was observed. 99103116 lsoalcohol synthesis from CO/HP feedstocks Apesteguia, C. R. et al. Stud. Surf Sci. Catal., 1998, 119, (Natural Gas Conversion V), 485-490. A study of the synthesis of methanol and isobutanol from synthesis gas over copper-containing Mg,Ce(Y)O, catalysts. The influence of the catalyst component, temperature and contact time on isoalcohol productivity was determined. By adding methanol, ethanol or propanol to the reactant feed the reaction pathway for isoalcohol synthesis was studied. 99103117 Kinetic behavior of the Ru/TiOa catalyst in the reaction of partial oxidation of methane Elmasides, C. et al. Stud. Surf Sci. Cataf., 1998, 119, (Natural Gas Conversion V), 801-806. In the partial oxidation of methane, the kinetic behaviour of the Ru/TiOz catalyst was investigated as a function of temperature and partial pressures of CH+ 02, CO, COz, Hz and HzO. The catalyst promotes, to a large extent, the direct formation of syngas from the reaction of methane and oxygen, while the reforming and water-gas shift reactions are negligible under these conditions. It is proposed that the reaction mechanism over the Ru/TiOz catalyst involves formation of CO-Hz and COz-Hz0 in two in series reaction routes, possibly on different active sites of the ruthenium surface. Part of Hz and, to a lesser extent, of CO is consecutively oxidized by adsorbed oxygen to Hz0 and COz giving the final product distribution. 99103118 Kinetic study of catalytic partial oxidation of methane to synthesis gas over NiILa203 catalyst Tsipouriari, V. A. and Verykios, X. E. Stud. Surf Sci. Catal., 1998, 119, (Natural Gas Conversion V), 795-800. An investigation was carried out into the kinetic behaviour of the Ni/LazOs catalyst in the partial oxidation of methane as a function of temperature and partial pressures of CH4 and Oz. The results suggest that the reaction mechanism over the Ni/LazOs catalyst involves adsorption of methane and oxygen on different sites, while the decomposition of CHI into carbon and hydrogen and the reaction of adsorbed carbon and oxygen towards CO are suggested as the rate determining steps (RDS). 99103119 KTl’s innovative reformer design for hydrogen and syngas plant Giacobbe, F. and Loiacono, 0. Stud. Surf Sci. Carol., 1998, 119, (Natural Gas Conversion V), 937-942. The paper describes the KTI heat exchanger reformer, a regenerative reformer which has a metal sleeve surrounding the catalyst tubes. The flue gas flows downward from the burners to the bottom of the sleeve, then upward inside the sleeve and makes contact with the catalyst tube.