Showing papers on "Carbochemistry published in 2000"

Basic Studies of Coal to Enhance Its Development as a Clean Fuel

Abstract: Coal is the most abundant source of energy. However, there is a need to develop cleaner, and more efficient, economical, and convenient coal conversion technologies. It is important to understand the organic chemical structure of coal for achieving real breakthroughs in the development of such coal conversion technologies. A novel computer-assisted modeling technique based on the analysis of {sup 13}C NMR and gel permeation chromatography has been applied to predict the average molecular structure of the acetylated product of a depolymerized bituminous Indian coal. The proposed molecular structure may be of practical use in understanding the mechanism of coal conversions during the processes of liquefaction, gasification, combustion, and carbonization.

Coal Conversion Processes, Gasification

Abstract: Coal gasification is a well-proven technology that provides an excellent way to utilize vast resources of coal efficiently and cleanly. The near-term application of coal gasification is in conjunction with combined cycle systems to generate electricity. Modern coal gasification processes produce high pressure syngas, which can be fed as fuel to a gas turbine. The high efficiency derived from combining gas turbine cycles with steam turbine cycles, along with significant environmental benefits, makes coal gasification combined cycle (CGCC) power plants more attractive than conventional technologies that generate power by coal combustion. Gasification technologies are described for various types of feedstocks. The chemistry of coal gasification is presented and process results are shown for several coals with a focus on gasifier performance and process efficiency. Other potential applications of coal involve the use of syngas chemistry to produce chemicals.

Coal Conversion Processes, Carbonization

Abstract: Carbonization of coal entails heating coal to high temperatures in the absence of oxygen to distill out tars and light oils. This process is used to produce metallurgical coke for use in iron making blast furnaces and other smelting processes. A gaseous by-product referred to as coke oven gas or coal gas is also formed along with ammonia, water, and sulfur compounds. Coke over gas is a valuable heating fuel. Other carbonization by-products are usually refined within the coke plant to produce commodity chemicals. Coking coals and the various coal constituents that lead to the production of high quality cokes are described. The carbonization process, including the coking mechanism and design of coke ovens, is discussed as are coke properties and coke uses. Keywords: Coal; Carbonization; Cokemaking; Coking mechanism; Coke ovens; Battery operation; Formcoke process

Coal Conversion Processes, Liquefaction

Abstract: Coal liquefaction involves taking the solid coal to liquid hydrocarbon and oxygenate products. Both direct and indirect routes, the latter being known as the Fischer-Tropsch process, are known. Direct liquefaction utilizes hydrogenation (hydroliquefaction) or pyrolysis of the coal in a single processing sequence. Indirect liquefaction processes involve the production of synthesis gas, ie, coal gasification, as the first step, followed by catalytic conversion to liquid products. Liquefaction processes that have moved beyond the laboratory are discussed. Flow diagrams, reactor types and conditions, catalytic composition, conversion efficiency, and product make-up are given.