利用CaO/PAC选择性去除预水解液中木质素

利用CaO结合聚合氯化铝(PAC)来选择性去除预水解液中的木质素。分别探讨了酸化法、碱化法及其结合PAC选择性去除木质素的效果,并分析了PAC选择性去除木质素的机理。结果表明:酸化法pH值为1.5时,木质素去除率最大(杨木15.68%,麦草18.76%);而采用CaO调节pH值为12时,木质素去除率最大(杨木33.33%,麦草30.67%),碱化法去除效果优于酸化法。添加CaO将pH值调至10并使PAC浓度为36 mmol/L时,预水解液中木质素的去除率(杨木50.59%,麦草49.17%)及选择性(杨木86.57%,麦草82.76%)效果最佳。

Selectively Removing Lignin from Pre-hydrolysis Liquor by Combined CaO/PAC Method

A noval process, based on the combination of CaO and polyaluminium chloride (PAC) flocculation, was developed to selectively remove lignin from pre-hydrolysis liquor (PHL).The selective removals of lignin by using acidification, alkalization and combined process were investigated and the mechanism of removal lignin by PAC was investigated.The results showed that the maximum removal rates (poplar chip 15.68% and wheat straw 18.76%) of acidification were obtained at pH value of 1.5 and the removal rates of CaO treatment reached the maximum (poplar chip 33.33% and wheat straw 30.67%) as adjusting the pH value with CaO to 12.After the CaO treatment for the hydrolysate, both the removal rate and selectivity of lignin were higher than those of acidification treatment.Using CaO to adjust pH to 10 and then adding PAC to 36 mmol/L, the removal rate of lignin in pre-hydrolysis liquor reached the maximum, the numbers were 50.59% and 49.17% for poplar chips and wheat straw, respectively.Meanwhile, the selectivites were the best, represents 86.57% and 82.76% for poplar chips and wheat straw, respectively.