Technoeconomic assessment of ethanol production via thermochemical conversion of biomass by entrained flow gasification

The production of ethanol via entrained flow gasification of biomass and subsequent catalytic synthesis is economically assessed by considering current and future scenarios. In the current scenarios, the process plants proposed only make use of available technologies and state-of-the-art mixed alcohol catalysts (Rh-Mn/SiO₂ and KCoMoS₂ catalysts). In the future scenarios, the effects of improvements in MoS₂ catalyst performance and the availability of pressurized solid biomass feeding systems are assessed. A plant size of 2140 dry tonnes/day of wood chip (500 MW_th) is considered with the criteria of being energy self-sufficient. The economic results are discussed and also compared with state-of-the-art production of biochemical lignocellulosic ethanol.The results reveal that although the Rhodium catalyst presents better performance than MoS₂ catalysts in terms of selectivity to ethanol, the high price of the Rhodium catalyst leads to higher production costs. For current catalysts, the minimum ethanol selling price (including 10% rate of return) is in the range of 0.90-1.25 $/L. In a future scenario, expected improvements in MoS₂ catalyst performance would lead to a decrease in price to 0.71 $/L. Besides, if biomass piston feeders were commercially available, as an alternative for flash pyrolysis pre-treatment, the minimum ethanol selling price would decrease to 0.55 $/L.