Technoeconomic assessment of lignocellulosic ethanol production via DME hydrocarbonylation

In this study, a new thermochemical route to produce lignocellulosic ethanol based on DME (dimethyl ether) hydrocarbonylation is proposed and economically assessed. The process is designed and evaluated using current kinetic laboratory data for hydrocarbonylation reactions. Only available technologies or those expected to be available in the short term are considered for the process design, which involves biomass pretreatment and gasification (indirect circulating fluidized bed), gas clean-up and conditioning, methanol synthesis, DME production by methanol dehydration and DME hydrocarbonylation. The process is designed to be both energy self-sufficient and electrical energy neutral. For a plant size of 2140 dry tonnes/day of wood chip (500 MW HHV) the minimum selling price of ethanol (for a 10% rate of return and a biomass price of 66 $/dry tonne) ranges from 0.555 to 0.592 USD 2010/L of automotive grade ethanol with fixed capital costs between 333 and 352 M USD 2010. Energy efficiency of biomass to ethanol ranges from 44.35 to 45.53% (high heating value basis). These results compare favorably with the "state of the art" production of ethanol via biochemical pathway from lignocellulosic biomass, revealing that the DME hydrocarbonylation route is a promising one that could be cost-competitive in the near future.