Showing papers on "Carbochemistry published in 1996"

Low temperature steam-coal gasification catalysts

Abstract: Shrinking domestic supplies and larger dependence on foreign sources have made an assortment of fossil fuels attractive as possible energy sources The high sulfur and mineral coals of Illinois would be an ideal candidate as possible gasification feedstock Large reserves of coal as fossil fuel source and a projected shortage of natural gas (methane) in the US, have made development of technology for commercial production of high Btu pipeline gases from coal of interest Several coal gasification processes exist, but incentives remain for the development of processes that would significantly increase efficiency and lower cost A major problem in coal/char gasification is the heat required which make the process energy intensive Hence, there is a need for an efficient and thermally neutral gasification process Results are described for the gasification of an Illinois No 6 coal with transition metal catalysts and added potassium hydroxide

Suitability of Australian bituminous coals for use in slagging gasifiers

Abstract: Commercial development of coal based integrated gasification--combined cycle (IGCC) power generation technologies will expand world markets for coals for use in slagging gasifiers. However, the high ash fusion temperatures of Australian export thermal coals pose a concern in such technologies. In this work slag viscosity versus temperature curves have been used to evaluate slag tappability and hence the suitability of bituminous coals for such use. The amount of CaCO{sub 3} required as a flux is used to rank the coals for use in slagging gasifiers. Several coals appear suitable without flux addition. For the other coals tested, flux requirements ranged between 2 and 11% CaCO{sub 3} by weight of coal, for tapping at 1400 C. A number of major operational and developing mines in New South Wales and Queensland appear well placed to compete in this emerging coal market.

Coal liquefaction kinetics

Abstract: Understanding the mechanisms of uncatalyzed direct coal liquefaction by means of reaction kinetics has been a long sought goal. Curran et al. in 1967 and Wiser in 1968 and Neavel in 1976 measured the rates of liquefaction of various coals and postulated a free radical mechanism to explain the data obtained. The kinetics as determined by these and other workers is described in detail by Gorin in Chapter 27 of Elliott`s Second Supplementary Volume to the Chemistry of Coal Series. However, it has been well known that most coals contain some material extractable by organic solvents. The solvents used in direct coal liquefaction would of course be expected to also extract soluble material as well as effect the liquefaction reaction. If the extractable material were a significant quantity in the coal, it would seriously affect the kinetics. Cassidy et al. used a stirred autoclave with a sampling port at the bottom in their kinetic studies. They observed that hot charging the coal rapidly formed an oil which they considered to originate predominantly from the {open_quote}guest component{close_quote}, i.e., extractables, in the lignite they studied. Also, the free radical nature of the liquefaction process would be expected to produce secondary reaction productsmore » which would complicate the kinetics as well as lead to retrograde products. The kinetics of the liquefaction of a bituminous and subbituminous coal are reported.« less