Fractionation of herbaceous biomass by ammonia-hydrogen peroxide percolation treatment
1996
Kim, S.B. | Lee, Y.Y.
Treatment with ammonia and hydrogen peroxide was investigated as a means of fractionating herbaceous biomass. The main feature of this process is that aqueous forms of these reagents are pumped simultaneously into a packed-bed flow-through-type reactor (percolation reactor) under a semibatch mode with ammonia being recycled. Experimental tests on corn cobs/stover mixture (CCSM) and switchgrass feedstocks have proven that a high degree of fractionation of biomass into three major components is attainable under this process scheme. The extent of delignification was 94-99%. It was achieved at a representative condition of 170 degrees C, 0.28 g loading of H2O2/g biomass, and 10 wt% ammonia concentration. At the same time, about 80% of total hemicellulose in the biomass was separated out into the effluent primarily in the form of xylose oligomers. Decomposition of sugar components was insignificant. The remaining solids had a composition of 80-93% glucan, 5-10% xylan, and 1-6% lignin. Selected solid samples, obtained under near-optimum conditions, exhibited a chemical composition close to that of commercial alpha-cellulose. The enzymatic digestibilities of these solid samples were substantially higher than that of alpha-cellulose.
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