Abstract: To improve the enzymatic saccharification of lignocellulosic biomass, ethylene glycol assisted with hydrochloric acid was used for pretreating hickory shell in this study. After the optimization in oil-bath system, the optimal pretreatment condition was obtained as following:the pretreatment media was hydrochloric acid-ethylene glycol-water (1.2%:88.8%:10%, mass ratio), pretreatment temperature 130℃, and pretreatment time 30min. In order to reduce the pretreatment temperature and time, microwave radiation was employed to assist the pretreatment with hydrochloric acid-ethylene glycol-water (1.2%:88.8%:10%, mass ratio) media, and the optimal pretreatment condition was achieved as following:microwave radiation temperature 100℃, microwave radiation time 5min, and microwave radiation power 200W. These results showed that the saccharification rate of pretreated hickory shell was higher than that of untreated one. After the pretreatment with oil-bath and microwave radiation, the reducing sugar yield from the enzymatic hydrolysis could reach 88.6% (oil bath) and 74.2% (microwave) after 72h. By using electron microscopy (SEM) and infrared spectroscopy (FT-IR) analysis, the structure of pretreated hickory shell was destroyed, the structure became loose, and porous were easier to be enzymatically hydrolyzed, which increased the enzyme accessibility, thereby greatly improving the saccharification rate. Therefore, the pretreatment with hydrochloric acid-ethylene glycol-water solution can improve the efficiency of the enzymatic saccharification of hickory shell.

Key words: waste oil with high acid value, pre-esterification, preparation, biodiesel, scale-up

摘要： 为了有效解决现有酯化体系中存在反应慢、时间长、产能低等问题,提出了一种高温下甲醇连续酯化反应的新技术,并采用该技术以对甲苯磺酸为催化剂催化高酸值废弃油脂预酯化试验研究。系统讨论了不同酯化方法对反应的影响,并着重研究了工艺条件对预酯化效果的影响。实验结果表明:高温下甲醇连续酯化的新技术可显著提高酯化反应效率,在反应温度120℃、甲醇流量4.0mL/min、催化剂加入量0.8%的条件下,酯化率达98.8%以上,可将油脂的酸值降至1.0mgKOH/g以下,满足下一步酯交换制备生物柴油的要求;并基于实验研究的基础上将该技术工艺对不同酸值的废弃油脂进行了放大试验研究,皆取得了较好的酯化效果,为产业化、规模化的应用提供理论依据和参数指导。

关键词: 高酸值废弃油脂, 预酯化, 制备, 生物柴油, 放大