Low-temperature alkaline soaking coupled with circulating alkali-oxygen cooking: A novel method for whole utilization of bagasse

Abstract

The addition of oxygen accelerates lignin dissolution and reduces the cooking temperature during alkali-oxygen cooking. However, hemicellulose could oxidized into furan and organic acids, leading to the increasing viscosity of black liquor and hemicellulose loss. To retain the hemicellulose and reduce the circulating black liquor viscosity, low-temperature alkaline soaking before alkali-oxygen cooking was implemented. Alkaline soaking extracted about 70 % of pentose and 62 % of lignin from the bagasse. Further mild alkali-oxygen cooking could gained the 43 % yield pulp with brightness above 50 %, and the viscosity of the circulating black liquor was lower than 0.1 Pa∙s after five time cyclic cooking. The results show that low-temperature alkaline soaking coupled with circulating alkali-oxygen cooking could effectively extracts hemicellulose from bagasse while producing clean pulp with low-viscosity circulating black liquor. This work presents a novel method for realizing total component utilization of bagasse.