Coal gasification chemical reactions

Feldmann, H. F., "The Role of Chemical Reaction Engineering in Coal Gasification," Chemical Reaction Engineering Reviews, Advances in Chemistry, No. 148, pp. 132-155 (1975). 

In Great Britain, the Imperial Chemical Industries, Ltd., has developed a fluidized coal gasification process (32) using combustion of part of the fuel with air to supply the heat necessary for the endothermic steam-carbon reaction. This procedure is divided into three steps carbonization, air-blowing, and steam-blowing. The first and third steps operate with fluidized beds, and the second with a dilute suspension. Powdered coal is fed into the carbonization vessel, where it is heated by combustion of some of the carbonization gases. The powdered char is blown into a feed hopper connected with the air-... 

Of the indirect liquefaction procedures, methanol synthesis is the most straightforward and well developed [Eq. (6)]. Most methanol plants use natural gas (methane) as the feedstock and obtain the synthesis gas by the steam reforming of methane in a reaction that is the reverse of the methanation reaction in Eq. (5). However, the synthesis gas can also be obtained by coal gasification, and this has been and is practiced. In one modern low-pressure procedure developed by Imperial Chemical Industries (ICI), the synthesis gas is compressed to a pressure of from 5 to 10 MPa and, after heating, fed to the top of a fixed bed reactor containing a copper/zinc catalyst. The reactor temperature is maintained at 250 to 270°C by injecting... 

The chemical reactions taking place during the gasification of coal are well known. Some of these are listed in Table 3. 

Coal gasification to produce syngas can be regarded physically as a gas/solid reaction. From a chemical point of view, it can be considered as the partial oxidation of carbon or as the reduction of water with carbon. However the total process is much more complex and only describable using numerous... 

The gasification process involves the combustion of coal with a restricted amount of oxygen. For the most part the oxygen is provided by a separate air separation unit (ASU) rather than air which would otherwise introduce a large amount of nitrogen into the synthesis gas. The principal chemical reactions are ... 

Generally, gasification kinetics research includes the study of rates and mechanisms of gasification reactions and the effect of factors on the reaction rates. Reactions in coal gasification are mainly heterogeneous. Besides the chemical reaction (heterogeneous and homogeneous), some physical processes such as adsorption, diffusion, heat transfer, and fluid mechanics also play important roles in this complicated process. 

In the hydrogen production from fossil fiiels, if it is chemical to chemical conversion such as by tire steam-coal gasification reaction or by tire steam-methane reforming reaction, there is no such thermodynamic limitation by the Carnot efficiency. 

Derm MM, Shiimar R (1987) Coal Gasification Reactors. In Carberry JJ, Varma A (eds) Chemical Reaction and Reactor Engineering, Marcel Dekker Inc, New York, Chap 8, pp 499-543... 

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