| Abstract:Using hot water prehydrolysis can effectively separate part of hemicelluloses from the wood in dissolving pulp manufacture process. It will provide possibility for wood biorefinery. In this paper, we studied the effect of hot water prehydrolysis on the dissolving of carbohydrate of the pine and saccharides consistence in the hydrolysate. It was found that the order from fast to slow of saccharides dissolution from the wood was arabinose, galactose, mannose, xylose and glucose. During prehydrolysis, the carbohydrates were degraded. Only part of degraded hemicelluloses was removed and dissolved into hydrolysate, most of hemicelluloses would be removed in the subsequent cooking and bleaching processes. At a prehydrolysis temperature of 180℃, the saccharides consistence in the hydrolysate decreased quickly with hydrolysis time, the furfural and hydroxymethylfurfural consistence increased quickly with hydrolysis time, it was unfavorable to hydrolysate fermentation for ethanol production. At last, the effects of 170℃ hot water prehydrolysis on the major constituents of the pine such as pentosan, extractive of benzene-alcohol, holocellulose, lignin and ash were investigated. The results showed that pentosan and ash contents decreased with increasing prehydrolysis time; while the extractive content of benzene-alcohol increased with increasing prehydrolysis time; the holocellulose content decreased rapidly in the first, 90 minutes of prehydrolysis, it almost kept constant afterword; the lignin content decreased first and then increased slightly later. |
