TWO STAGE CONTINUOUS STEAM PRE-TREATMENT OF LIGNOCELLULOSIC BIOMASS

摘要

Disclosed is a method of steam explosion pretreating biomass in a two stage steam pretreatment process for improved carbohydrate fractionation. The first stage steam pretreatment is carried out by heating the biomass to a first stage temperature of 140° C. to 180° C. for a first stage time of 30 minutes to 2 hours at a first stage pressure of 105 to 150 psig. The second stage steam pretreatment is carried out by heating the biomass to a second stage temperature of 190° C. to 210° C. for a second stage time of 2 to 10 minutes at a second stage pressure of 167 to 262 psig. The biomass may be initially conditioned by atmospheric steam heating and adjusting the moisture content of the biomass. Hemicellulose sugars and inhibitors (inhibitory compounds) to downstream hydrolysis and fermentation are preferably removed between the first and second steam pretreating stages, more preferably after each steam pretreatment stage.

主权项

1. A pretreatment process for the fractionation of carbohydrates from lignocellulosic biomass, comprising:
a) conditioning the biomass by atmospheric steam heating to adjust a moisture content of the biomass and generate a conditioned biomass; b) subjecting the conditioned biomass to high pressure steam pretreatment to obtain steam pretreated biomass; c) rapidly depressurizing the steam pretreated biomass to obtain pretreated biomass; and d) separating hemicellulose sugars from the pretreated biomass;wherein the high pressure steam pretreatment is a two stage high pressure steam pretreatment including
i) pretreating the biomass in a first stage at a first severity by heating the biomass to a first stage temperature of 140° C. to 180° C. at a first stage pressure of 105 to 150 psig and for a first stage time of 30 minutes to 2 hours; and ii) pretreating the biomass in a second stage at a second severity higher than the first severity by heating the biomass to a second stage temperature of 190° C. to 210° C., at a second stage pressure of 167 to 262 psig, and for a second stage time of 2 to 10 minutes.