微波-酸化汽爆木质纤维素预处理试验研究

Experimental Study on Microwave-Acidification Steam Explosion Pretreatment for Lignocellulose

为提高木质纤维素预处理的原料利用率及经济效益,提出了微波-酸化汽爆预处理并对其进行了试验研究。以玉米芯为例,对比研究了木质纤维素类原料微波-酸化汽爆预处理和酸化汽爆预处理后水解液中糖的相对比例,分析了残余固形物中纤维素的含量,讨论了微观结构的变化情况,优化了前者的微波处理功率和微波处理时间。试验结果显示,相比酸化汽爆预处理,微波-酸化汽爆预处理后水解液中糖的相对比例更高;在压力不足以使纤维素降解时,残余固形物中纤维素的含量更高;原料微观结构更加疏松多孔,比表面积更大;随着微波处理功率增大和微波处理时间延长,水解液中木糖和总糖的相对比例以及残余固形物中纤维素相对比例均先增大后减小。研究结果为原料利用率更高、成本更低的木质纤维素预处理技术的开发提供了新的思路。

To improve utilization rate of the raw material and economic benefit during the process of lignocellulose pretreatrnent, the microwave-acidification steam explosion pretreatment was proposed and the experiment research on it was performed. The percentage of sugar in the hydrolysate, the cellulose content in the residual solid and the change of microstructure after the microwave-acidification steam explosion pretreatment and the acidification steam explosion pretreatment for lignocelluloses was compared, taking the corn cob as an example. The power and the time of the microwave-acidification steam explosion pretreatrnent was optimized. The experimental results revealed that the percentage of the sugar in the hydrolysate was higher, the cellulose content in the residual solid was higher if the pressure was not enough to make cellulose degrade, the microstructure of the raw material was more porous and specific surface area was bigger, in contrast to the acidification steam explosion pretreatment. The percentage of xylose and total sugar in the hydrolysate and cellulose in the residual solid first increased then decreased with the increment of microwave power and extension of microwave time. Results of the study provided a new idea to develop the lignocellulose pretreatment technology with higher utilization rate of the raw material and the lower cost.