DLCA (ch) pretreatment brings economic benefits to both biomass logistics and biomass conversion for low cost cellulosic ethanol production

Abstract Densifying lignocellulosic biomass with chemicals (calcium hydroxide) (DLC(ch)) followed by regular steam autoclave treatment (DLCA(ch)) is a novel pretreatment method, which unlocks highly fermentable sugars and showed great potential. This study investigated the economics of DLCA(ch) based biorefinery for cellulosic ethanol production and studied the effects of solid loading, enzyme dosage, enzyme price and biorefinery scale on the economics. Compared with dilute acid pretreatment based biorefinery, DLCA(ch) based biorefinery showed much lower feedstock logistics cost, and the savings in feedstock logistics almost offset the DLC(ch) pretreatment cost. DLCA(ch) based biorefinery exhibited higher ethanol yield and lower pretreatment costs. When the biorefinery scale was 2000 Mg rice straw per day, the total capital investment and minimum ethanol selling price of DLCA(ch) based biorefinery were 17.9% and 30.0% lower, respectively, compared to dilute acid pretreatment based biorefinery. This work demonstrated the great potential of DLCA(ch) pretreatment for the commercial production of cellulosic ethanol.