直接精馏法提取纤维素乙醇

采用直接精馏法研究了高固含量(质量分数)、高黏度的玉米秸秆发酵醪液的精馏工艺,设计了带搅拌桨的不锈钢筛板-填料精馏塔,确定了固含量为11.56%的发酵醪液的幂律模型本构方程,进而得到塔釜中发酵醪液的黏度和搅拌桨转速的关系。在进料量为2.7 L/h、进料体积分数为10%左右、进料温度为30℃、操作压力为常压的条件下,考察了进料位置、回流比、搅拌桨转速等操作条件对纤维素乙醇精馏的影响。实验结果表明:第27块塔板进料、操作回流比5.0、搅拌桨转速36 r/min为最佳操作条件,塔顶乙醇收率可达到99%以上。

Extraction of ligno-cellulosic bio-ethanol by direct distillation

The distillation process of corn stover fermentation slurry with high solid loading and high viscosity was studied by direct distillation,and the steel tray-packing distillation column with mixing propeller was designed.The power law module of fermentation slurry with solid loading(mass fraction) of 11.56% was given,and the relation between viscosity of fermentation slurry and rotational speed of mixing impeller was established.The effect of feed location,reflux ratio,rotational speed of mixing propeller on ligno-cellulosic bio-ethanol distillation was observed at feed flow rate 2.7 L/h,feed volume fraction about 10%,feed temperature 30 ℃ and normal pressure.The results show that under the optimum conditions of 27th feed plate,reflux ratio 5.0 and rotational speed of mixing impeller 36 r/min,the overhead ethanol yield can reach above 99%.