生物质预处理对半纤维素提取及后续CTMP制浆的影响

Effects of Biomass Pretreatment on the Extraction of Hemicelluloses and the Pulp Quality of the Subsequent CTMP

在化学热磨机械浆(CTMP)制浆前对原料进行预处理,旨在保证浆料质量的前提下,实现生物质资源的充分和高效利用.采用自水解、酸法、碱法不同预处理方式对生物质进行预处理,通过改变预处理强度因子(温度和时间的综合变量),考察预抽提效果及CTMP成浆质量.研究结果表明:随着预处理条件的不断增强,水解木片得率降低,半纤维素溶出量增加,水解后木片中综纤维素、聚戊糖和酸溶木素的含量明显下降,生物酶对麦草葡萄糖的转化率提高.相比未经过预处理的原料,预处理后的原料在制浆过程中压力磨浆能耗和PFI打浆能耗分别降低,同时浆张抗张指数和撕裂指数均提高.

Pretreatment of the raw material before CTMP(Chemi-thermomechanical Pulp)pulping was performed,in order to make full use of biomass resources and produce value-added products,without lowering the pulp quality.Different pre-extraction methods,such as autohydrolysis,acid and alkali pre-extractions,were used for the pretreatment to study the ef-fects of pre-extraction with various severities on the pulp quality of the following CTMP(i.e.,the comprehensive variablesof the pretreatment temperature and time).The results showed that,as the condition aggravated continually,the yield of the hydrolyzed chips decreased and the amount of the dissolved hemicelluloses increased.The contents of holocellulose, pentosan and acid soluble lignin in the hydrolyzed chips decreased dramatically with the increase of the pretreatment severity.The pretreatment shortened the enzymatic hydrolysis time and improved the conversion of glucose of wheat straw.Compared with the original wood chips,the hydrolyzed chips had not only a lower pressurized refining energy con-sumption but also a higher energy saving in PFI refining.In addition,the CTMP made of hydrolyzed chips had a higher ten-sile index and an enhanced tear index.