Dry dilute acid pretreatment by co-currently feeding of corn stover feedstock and dilute acid solution without impregnation

•Dry dilute acid pretreatment (DDAP) with co-currently feedstock feeding was performed.•DDAP carried out in the reactor with helical agitator to improve mass transfer.•Similar efficiency of DDAP obtained using impregnated and non-impregnated corn stover.

Impregnation of lignocellulose materials with dilute acid solution is a routine operation in conventional dilute acid pretreatment. The dry dilute acid pretreatment (DDAP) at high solids content up to 70% is naturally considered to require longer impregnation time. In this study, a co-currently feeding operation of corn stover and dilute sulfuric acid solution without any impregnation was tested for DDAP. The DDAP pretreated corn stover without impregnation is found to be essentially no difference in pretreatment efficiency compared to those with impregnation in the helically agitated reactor. The yield from cellulose to ethanol in SSF again shows no obvious difference between the DDAP pretreated corn stover with and without impregnation. This study suggests that impregnation in DDAP was not necessary under the helical agitation mixing. The results provided a useful way of cost reduction and process simplification in pretreatment.

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