摘要
在半连续实验装置上 ,运用非等温动态萃取技术 ,进行了木材亚 超临界乙醇 (有或无水 )萃取特性的研究 ,主要考察了压力和水对木材亚 超临界乙醇萃取过程的影响。研究结果表明 ,木材主要萃取过程可分为两个阶段 ,第 1阶段温度范围为 2 0 0℃～ 2 80℃ ,在 2 5 0℃左右萃取物生成速率有极大值 ;第 2阶段温度范围为 2 80℃～ 380℃ ,在 35 0℃左右萃取物生成速率有极大值 ,该阶段同时生成大量气体。提高压力或增加混合溶剂中水的摩尔分数均能使木材转化率和萃取物产率增加 ,气体产率降低。压力效应主要体现在 2 5 0℃以后 ,而水效应主要体现在 30 0℃以前。通过温度、压力和混合溶剂中水的摩尔分数等过程变量的调控 ,亚
The characteristics of sub and supercritical extraction of wood with ethanol or ethanol water were studied in a semi continuous experimental apparatus using the non isothermal dynamic extraction technique,the effects of pressure and water on the sub and supercritical extraction of wood with ethanol were mainly investigated.The results showed that the main extraction process of wood could be classified as two phases roughly,the temperature range in the first phase was from 200℃ to 280℃,and the extract formation rate had the maximum value at about 250℃.The temperature range in the second phase was from 280℃ to 380℃,and the extract formation rate had the maximum value at about 350℃,a great quantity of gas was generated in this phase simultaneously.Wood conversion and extract yield increased and gas yield decreased with the increasing of pressure and the molar fraction of water in ethanol water mixture.The effect of pressure mainly reflected after 250℃,and the effect of water mainly reflected before 300℃.From an engineering standpoint,the sub and supercritical extraction technology could be suited to the different conversion ways of wood resources through regulating and controlling process variables such as temperature,pressure and the molar fraction of water in ethanol water mixture.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2002年第4期117-124,共8页
Scientia Silvae Sinicae
基金
国家自然科学基金资助项目 (3 9670 5 91)
