Gasification of coal Apr05

Gasification of coal

Gasification of coal Gasification of coal is a high temperature process which is optimized to produce a fuel gas with a minimum of liquid and solids. This process consists of heating the feed material coal in a vessel with or without the addition of oxygen. Water may or may not be added. Due to decomposition reactions which take place in the vessel, a mixture of gases is produced where H2 and CO gases are prominent. Other gases in the mixture are water, methane and CO2. The mixture of CO and H2 is called synthesis gas or syngas.  After the gasification of coal, petroleum liquid products are produced by Fischer Tropsch process. The basics of the gasification process is given in Fig.1 Fig 1 Basics of the gasification process The gasification process is shown in Fig.2 Fig 2 Gasification process History and present development The original process was developed by the German researchers Franz Fischer and Hans Tropsch at the Kaiser Wilhelm institute in 1920s. The process was used by Germany and Japan during World War II to produce alternative fuels. Since then many adjustments and refinements have taken place and the term Fischer- Tropsch applies to a number of similar processes. Sasol has built a plant at Sasolburg with the prime objective of converting low grade coal into petroleum products and the first liquid was produced from this plant in 1955. Lurgi and Sasol made a joint venture in 2001 and Sasol-Lurgi is presently the sole licensor for Sasol- Lurgi Fixed Bed Dry Bottom (FBDB) gasification. According to a recent survey by the Gasification Technologies Council , there are 161 existing and planned commercial scale gasification plants worldwide. This represents a total of 414 gasifiers with a total synthesis gas production of 446 million...