Optimum Design of Coal Gasification Plants

This paper deals with the optimum design of heat recovery systems using the Texaco Coal Gasification Process (TCGP). TCGP uses an entrained type gasifier and produces hot gases at approximately 2500oF with high heat flux. This heat is removed by using a combination of radiant/convective waste heat boiler or by direct water quench before processing of the raw gas. The selection of an optimum heat recovery system is a function of the product slate, overall economics, and the technical risks associated with the heat recovery equipment. An extensive use of heat recovery equipment is not necessarily more economical than a simpler system with modest thermal efficiency. A full heat recovery mode consisting of radiant and convective boilers along with economizers is recommended for Coal Gasification Combined Cycle to maximize energy efficiency. A water quench mode is suggested for hydrogen production because of the need to adjust the H2O/CO ratio for shift conversion. A partial heat-recovery mode is recommended for power/methanol co-production plant. These heat recovery systems are discussed in detail along with the economics associated with each system