Desulfurization of peroxyacid treated Indonesian coals by organic base

0 1 Solid fuels (preparation) of residual char and ash formation. In general, at higher pressures, coal particles burn quicker and form finer ash particles. Increasing reactant pressure enhances char combustion and gasification reaction rate, which can be understood by an adsorption-desorption mechanism. These factors have been applied to the understanding of a practical high-pressure gasifier. Most of the work published has been at the lower temperatures (typically
Preparation 03/00477 Biodesulfurization of coal in stirred reactor. Kinetic models Cara, J. et al. Zngenieria Quimica (Madrid, Spuin), 2002, 34, (386), 231242. (In Spanish) Biodesulfurization of coal using Thiobacillus ferroxidans was studied in stirred reactors to detect reaction kinetics. The specific biodesulfurization velocity is dependent on initial inoculum and on coal type treated and was 0.299 day-‘. 03/00478 Coal drying improves performance and reduces emissions Bullinger, C. et al. Proceedings qf’ the International Technical Conference on Coal Utilization & Fuel Systems, 2002, 2, (27), 639-650. Lignite and subbituminous coals from the western USA are attractive fuels for power plants due their low cost and emissions; however, lignite and PRB coals typically contain high amounts of moisture and/ or ash. When high moisture coals are burned in utility boilers, ~7% of the fuel heat input is used to evaporate fuel moisture. This results in higher fuel flow, higher stack flue gas flow, higher parasitic power, lower plant efficiency, and higher mill maintenance costs vs. lowmoisture coal. Efforts are underway in Europe and Australia to develop efficient coal dewatering and drying processes. Thermal drying and dewatering and mechanical dewatering are used. Thermal processes typically used depend on a high-grade heat to evaporate or remove moisture from coal. Field test results, conducted with dried lignite coal at a 550 MW unit in North Dakota, and a coal drying process that uses a low-grade waste heat to evaporate a portion of fuel moisture from the lignite feedstock, are presented. Process layout, coal drying equipment, and fuel moisture impact, on plant performance and emissions are discussed. Improved boiler and unit performance, achieved during this test by removing 6% of fuel moisture was in 2.6-2.8%. This performance improvement was primarily due to a reduction in moisture evaporation loss, lower stack loss, and decrease in auxiliary power requirements. Assuming a capacity factor of 0.8, this 6% reduction in fuel moisture represents annual savings of $1.3 million for both units at the Coal Creek Station, North Dakota. If implemented on all US lignite and PRB units, it would represent annual savings of 134

Fuel

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Energy

Abstracts

May 2003

$19 million for lignite-fired plants, and $90 million for PRB-tired plants. Field test results were for 6.1% moisture reduction. Future work will include test burns with lower moisture content to detect the impact on boiler operations. This will also make it possible to detect the optimal coal moisture content. 03/00479 Deep cleaning of coal-derived fuel gases at high temperature in the ultra-clean process Slimane, R. B. et al. Proceedings of the International Technical Corzference on Coal Utilization & Fuel S\,stems, 2002. 2, (27). 1033. 1044. The Siemens Westinghouse Power Corporation and the gas Technological Institute are developing an innovative process for hot syngas cleanup, the ‘Ultra-Clean Process’, to meet the needs of advanced IGCC-based co-production of electrical power and chemical or fuel products. This process has two cleanup stages integrated in series and relies on the injection of dry sulfur and halide sorbent fines to accomplish contaminant removal to parts-per-billion levels. This paper reports on the work GTI recently completed to identify and evaluate suitable materials for each stage, their feed rates, and the operating temperature for each stage to satisfy the gas cleaning requirements. 03/00480 Desulfurization of peroxyacid treated Indonesian coals by organic base Ishak, M. A. M. et (11.ACGC Chemical Research Cornmunic,ution,v, 2002, 14, 14-25. Combustion of high sulfur coals is one of the fundamental reasons for problems with sulfur dioxide emissions. In order for high and medium sulfur coals to be utilized as clean fuel, the desulfurization techniques have to effectively remove both the inorganic and organic sulfur forms. Subsequent reaction on the mildly oxidized peroxyacetic acid treated Banjarmasin Haji Ali-Aliansar and Banjarmasin A coals with sodium benzoxide, which is a strong organic base, showed a further organic sulfur removal in both coals of approximately 46% and 30% respectively. The additional organic sulfur removal by the organic base strengthen the assumption that the C-S bonds have been broken due to the weakening of the bonds during the pretreatment oxidation by the formation of sulfones, sulfoxides and sulfonic acid from the divalent sulfur species that are present in the coals. The effect of organic base treatment on the pretreated coals showed that the coals micro-structures were not severely affected, as revealed by scanning electron microscope with energy dispersive X-ray (SEM-EDX). 03/00481 Detailed characterization of heteroatomcontaining molecules in light distillates derived from Tanito Harum coal and its hydrotreated oil Sumbogo Murti, S. D. et ul. Fuel, 2002, 81, (17), 2241-2248. Heteroatom-containing compounds in as-prepared and hydrotreated distillates produced from Tanito Harum coal were identified by the aid of gas chromatography with atomic emission detector (GC-AED) which can detect all the elements (C, H, N, S, 0) contained in the molecules. Alkylated benzothiophenes and dibenzothiophenes were found to be the major sulfur compounds in the original fraction, all of them being completely removed by the hydrotreatment at 350°C 10 MPa, and 60 min. Alkylated anilines, quinoline, indoles, and carbazoles were found in the original oil as nitrogen compounds. Two specific nitrogen compounds survived through the hydrotreatment, being identified as CllHzoN and Ci4H2sN, respectively, according to the calibrated elemental ratios by GC-AED and molecular weights measured by GC-MS (mass spectrometry). Such empirical formulae were quite similar to CiiHigN and C14H23N, respectively, which were detected by high MS and NMR after the concentration by extraction. Some sulfur compounds were observed in the non-aromatic fraction, while all the nitrogen compounds were completely concentrated in the aromatic fraction by the conventional column chromatographic separation. It is also noted that alkylated phenols, benzofurans and dibenzofurans were found as typical oxygen compounds in the distillate. Thus, GC-AED can identify the hetero-atom containing compounds based on the simultaneous multi-element analysis. 03/00482 Fluorine mineralisation from burning coal spoilheaps in the Russian Urals Sokol, E. V. et al. Mineralogy und Petrology, 2002, 75, (l-2), 23-40. Anhydrous iron, aluminum and fluorine-rich paralavas were found in the burned spoil-heaps of the Chelyabinsk coal basin, Russia. The rocks contain tridymite, anorthite, ferroan fluorine-bearing cordierite, fluorine-bearing mullite, periclase, fluorapatite, micas of the F-biotiteF-phlogopite series, fluortopaz, fluorite, and sellaite. The fluorine-rich minerals formed as a result of local thermal reactions of sedimentary carbonates and silicates with gaseous fluorine. During coal combustion fluorine concentrates in the annealed ankeritic marls where the increase of F is hundreds of times over its concentration in the initial sedimentary rocks. The formation of MgF:! and CaF2 promotes local melting at relatively low temperatures (T < 1OOO’C) with the residuum consisting of two immiscible liquids. One crystallizes as fluorides, the