03 Gaseous fuels (transport, storage)
Derived liquid fuels 05100054 Analysis of solvent extracts from coal liquefaction in a flowing solvent reactor El, W-Y. et al. Fuel Processing Technology, 2004, 85, (15), 1671-1687. Point of Ayr coal has been extracted using three solvents, tetralin, quinoline and l-methyl-2-pyrrolidinone (NMP) at two temperatures 350 and 450°C, corresponding approximately to before and after the onset of massive covalent bond scission by pyrolysis. The three solvents differ in solvent power and the ability to donate hydrogen atoms to stabilize free radicals produced by pyrolysis of the coal. The extracts were prepared in a flowing solvent reactor to minimize secondary thermal degradation of the primary extracts. Analysis of the pentaneinsoluble fractions of the extracts was achieved by size exclusion chromatography, UV-fluorescence spectroscopy in NMP solvent and probe mass. With increasing extraction temperature, the ratio of the amount having big molecular weight to that having small molecular weight in tetralin extracts was increased; the tetralin extract yield increased from 12.8% to 75.9%; in quinoline, increasing extraction temperature didn't have an effect on the molecular weight of products but there was a big increase in extract yield. The extracts in NMP showed the enhanced solvent extraction power at both temperatures, with a shift in the ratio of larger molecules to smaller molecules with increasing extraction temperature and with the highest conversion of Point of Ayr coal among these three solvents at both temperatures. Solvent adducts were detected in the tetralin and quinoline extracts by probe mass spectrometry; solvent products were formed from NMP at both temperatures.
05/00055 Poplar wood-water slurry liquefaction in the presence of formic acid catalyst Yilgin, M. and Pehlivan, D. Energy Conversion and Management, 2004, 45, (17), 2687-2696. In this study, the liquefaction of a poplar wood slurry in water with the presence of a formic acid (HCOOH) catalyst was investigated by considering the temperature, reaction time and wood particle size as the basic parameters. The experiments were continued until maximum oil yields were attained at different temperatures (250, 300 and 350°C) and showed that oil yields generally increased with temperature, but only up to a maximum value at each temperature and then were reduced. It was found that the particle size did not affect the liquefaction process, but loading the wood into the reactor as a slurry in water positively affected and increased the oil yields. It was concluded that this increment resulted from the prior penetration of the water into the wood particles.
05•00056 Proposal of a new rhelogical model of a highly loaded coal-water mixture (CWM) Matsuo, S. Kagaku Kogaku Ronbunshu, 2003, 29, (4), 526-533. (In Japanese) Effective use of coal was increasingly highlighted by the growing need for energy sources. Among them low-rank coal including subbituminous coal and brown coal is an abundant resource, but it has not been competitive in thermal coal markets due to its low heating value and a tendency for spontaneous combustion. One solution to this problem is the fluidized method, coal-water mixture (CWM) technique. This paper proposes a new rheological model of CWM. Several reports that have described the importance of a particle size distribution minimizes the void fraction among the coal particles in a low viscosity CWM. This model was semi-empirically derived from the concept of the average thickness of liquid layer among coal particles, and the relative viscosity of the slurry was described as a function of the void fraction and specific surface area of particles. The extension of the model to non-Newtonian fluids based on coagulation process was also discussed. The relative viscosity of CWM estimated by this model was compared with experimental data. The results were in good agreement with the experimental data when the void fraction of sample could be accurately calculated from the particle size distribution. In particular, a sample in which the void fraction of coal particles is minimal does not always show the lowest viscosity. It became clear that in theory, the relative viscosity of CWM is influenced not only by the void fraction but also by the sp. surface area of particles.
05100057 Synthesis and characterization of vegetable oil derived esters: evaluation for their diesel additive properties Dmytryshyn, S. L. et al. Bioresource Technology, 2004, 92, (1), 55 64. Trans-esterification of four vegetable oils; canola oil, greenseed canola oil from heat-damaged seeds, processed waste fryer grease and unprocessed waste fryer grease, was carried out using methanol, and K O H as catalyst. The methyl esters of the corresponding oils were separated from the crude glycerol, purified, and characterized by various methods to evaluate their densities, viscosities, iodine values, acid numbers, cloud points, pour points and gross heat of combustion,
fatty acid and lipid compositions, lubricity properties, and thermal properties. The fatty acid composition suggests that 80-85% of the ester was from unsaturated acids. Substantial decrease in density and viscosity of the methyl esters compared to their corresponding oils suggested that the oils were in their mono or di glyceride form. The lubricity of the methyl esters, when blended at 1 vol% treat rate with ISOPAR a') M reference fuel, showed that the canola methyl ester enhanced the fuel's lubricity number. From the analyses performed, it was determined that the ester with the most potential for being an additive or a substitute for diesel fuel is the canola methyl ester, whose physical and chemical characteristics are similar to diesel fuel.
03
G A S E O U S FUELS Sources, properties, recovery, treatment
05/00058 coal II
Bond forms of methane in porous system of
Weishauptovfi, Z. et al. Fuel, 2004, 83, (13), 1759 1764. Besides methane adsorbed in the porous system of coal, a considerable part is dissolved (absorbed) in macromolecular coal matrix. This part is usually included within the adsorbed methane without discerning the two different types of binding, which is of importance particularly at the gas-bearing assessment. Analysis of the complete sorption isotherm including both processes enabled to derive proportion of the adsorbed and desorbed methane from position and shape of the desorption branch of the isotherm. This analysis has shown that the amount absorbed exceeds the amount adsorbed both for bituminous and brown coal. The absorption in the macromolecular structure of coal matrix represents the fifth type of methane binding in coal. Measuring was carried out by gravimetric method.
05/00059 Geochemistry of natural gases in deep strata of the Songliao Basin, NE China Huang, H. et al. International Journal of Coal Geology, 2004, 58, (4), 231 244. Chemical composition and stable carbon isotopic studies were undertaken for 27 gas samples from deep strata of the Xujiaweizi Depression in the Songliao Basin to investigate their origin. Gas molecular and carbon isotopic compositions show great variety. Methane is the main component for all studied samples and its content ranges from 57.4% to 98.2% with an average of 90.1%. Gas wetness ranges from 0.8% to 16.7% with an average of 2.7%. The main non-hydrocarbon gases are carbon dioxide and nitrogen with an average of 4.0% and 3.2%, respectively. Carbon isotope data suggest that these deep strata gases are mainly coal-type gases mixed with minor amounts of associated (oil-type) gases. Coal-type gases are characterized by heavier carbon isotopic values and drier chemical compositions. These gases were generated from the Lower Cretaceous Shahezi Formation coals interbedded shales with type III kerogen during the postmature stage of hydrocarbon generation. Oil-type gases are characterized by lighter carbon isotope and higher wetness, which were generated from the Lower Cretaceous shales with type II kerogen in the shallow strata during the early mature stage of hydrocarbon generation. Mixing of two different gases causes unusual carbon isotopic distribution patterns, with lighter isotopic values in higher numbered carbons in most gases. The discovery of coal-type gases in the Songliao Basin provides new prospects for the exploration in this region.
Transport, storage 05•00060 A review of hydrogen storage systems based on boron and its compounds Fakiolu, E. et al. International Journal of Hydrogen Energy, 2004, 29, (13), 1371-1376. This work is a survey of utilization of boron for hydrogen storage. Boron is a promising element for hydrogen storage with its chemical hydrides and nanostructural forms. It is also used as an additive in nickel metal hydride battery systems to enhance hydrogen compatibility and performance. This present study will be a brief summary of hydrogen storage technology in general and focus on possible uses of boron and its compounds.
Fuel and Energy Abstracts January 2005
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