(537a) Technoeconomic Comparison of Indirectly Heated and Directly Heated Gasification Processes for Making Mixed Alcohols Via Catalytic Upgrading of Synthesis Gas

Processes to convert renewable lignocellulosic biomass materials such as corn stover, switch grass, or wood into transportation fuels are of significant interest today. Thermochemical routes using gasification and catalytic upgrading of the resulting synthesis gas are promising methods for making liquid transportation fuels and chemicals from biomass. Two major types of high temperature gasification processes are often considered: indirectly heated gasifiers that generate process heat through the combustion of residual char externally to the gasifier vessel (eg. In another vessel), and high pressure, directly heated gasifiers that use oxygen to generate heat in the gasifer by partially oxidizing some of the biomass insitu. Each of these processes has tradeoffs in the capital equipment and operating costs requirements affecting the process economics. This paper will compare the technoeconomics of the indirectly heated and directly heated gasification processes for making mixed alcohols via catalytic upgrading of synthesis gas.