(280b) Application of Graphical Techniques to Coal Gasification: Analysis of Partial Pressure and Target CO:H2 and CO2:H2 Ratios

The technique of graphically representing coal gasification has been proposed by Ngubevana et al¹.This method allows one to make simple assumptions and graphically represent the mass and energy balances around a gasifier. Using this method, one is also able to graphically represent the reaction equilibria. Different gasifier feeds and operating conditions can also be explored using this method. This paper looks at the application of this technique. Changes in possible gasifier product will be explored by looking at how the partial pressures of components change through the gasifier given certain operating conditions. Using this technique, one is also able to map out and determine the partial pressures of the components without actually calculating them; by simply knowing the gasifier product, one can easily determine these. The second and probably most important analysis that is done here is on the possible syngas composition (CO:H₂ and CO₂:H₂ ratios) from the gasifier. The traditional requirement of a CO:H₂ ratio of 2 for Fischer Tropsch (FT) synthesis is explored. Of biggest interest is a new FT chemistry as proposed by Patel et al². This chemistry proposes setting a CO₂:H₂ ratio of 3 as the target for FT synthesis. Some optimisation work is also done on the possible syngas composition for both the traditional and proposed new chemistry routes. The mass and energy balance are of course a very important part of all the analysis done here.

1. Ngubevana L, Hildebrandt D, Glasser D. AICHE National Spring Meeting 2007, Topical 6: 7th Natural Gas Utilization (T6), #30 ? Coal and Gas to Liquids I (T6001) .

2. Patel B, Hildebrandt D, Glasser D, Hausberger B.Thermodynamics Analysis of Processes. 1. Implication of Work Integration. Ind. Eng. Chem. Res. 44 (2005); 3529-3537.