Gasification of Coal

2.1 Background .................................................................................................... 26 2.2 Syngas Classification Based on its Heating Value ........................................ 28 2.2.1 Low-Btu Gas ...................................................................................... 29 2.2.2 Medium-Btu Gas................................................................................ 29 2.2.3 High-Btu Gas ..................................................................................... 29 2.3 Coal Gasification Reactions........................................................................... 30 2.3.1 Steam Gasification ............................................................................. 31 2.3.2 Carbon Dioxide Gasification ............................................................. 33 2.3.3 Hydrogasification ............................................................................... 34 2.3.4 Partial Oxidation ................................................................................ 35 2.3.5 Water Gas Shift (WGS) Reaction...................................................... 36 2.4 Syngas Generation via Coal Gasification...................................................... 38 2.4.1 Classification of Gasification Processes ............................................ 38 2.4.2 Historical Background of Coal Gasification and Its Commercialization ............................................................................. 39 2.4.3 General Aspects of Gasification ........................................................ 40 2.4.4 Gasification Processes........................................................................ 41 2.4.4.1 Lurgi Gasification ............................................................... 41 2.4.4.1.1 Lurgi Dry-Ash Gasifier .................................... 42 2.4.4.1.2 Slagging Lurgi Gasifier .................................... 44 2.4.4.2 Koppers-Totzek Gasification .............................................. 44 2.4.4.2.1 Koppers-Totzek Gasifier................................... 45 2.4.4.2.2 Features of the Koppers-Totzek Process.......... 46 2.4.4.2.3 Process Description of Koppers-Totzek Gasification....................................................... 47 2.4.4.3 Shell Gasification................................................................ 49 2.4.4.4 Texaco Gasification ............................................................ 50 2.4.4.5 In Situ Gasification ............................................................. 51 2.4.4.5.1 Potential Possibility of Using Microbial Processes for In Situ Gasification .................... 53 2.4.4.5.2 Underground Gasification System ................... 53 2.4.4.5.3 Methods for Underground Gasification ........... 55 2.4.4.5.4 Potential Problem Areas with In Situ Gasification....................................................... 56