酸性离子交换树脂催化酯化改质生物油的研究

Upgrading of Bio-oil via Esterification Catalysted with Acidic Ion-exchange Resin

以磺酸型离子交换树脂为催化剂,在模型反应的基础上,探讨了该催化剂在稻壳裂解油及其轻质馏分的催化酯化改质过程中的活性和效果,并通过气-质联用仪对酯化前后的生物油进行了成分分析.结果表明,酯化过程中采用的催化剂可以方便地分离和循环使用;生物油中的有机酸顺利地转化为相应的酯类(主要为乙酸乙酯).通过催化酯化改质后,两种生物油的理化特性均得到了有效改善,热值分别由16.80和12.76MJ/kg提高到20.08和18.33MJ/kg,相应提高了19.5%和43.6%;黏度分别由11.83和1.42mm2/s,下降到3.77和1.12mm2/s;水分分别为23.7%和28.4%,流动性明显增强,理化特性得到了明显提高.为生物油的精制加工提供了一种有效方法.

The corrosiveness of bio-oils is derived from organic acids, and it has limited the applications of bio-oil for current vehicles. But these acids can react with alcohol and convert into esters under mild condition with proper catalysts. The super-acid ion-exchange resin was applied to upgrade bio-oil and its light distillation fraction. The esterifiaction of bio-oils were preformed at 60℃ for 4 h, and the conversion of acetic acid approached 88%. Furthermore, the properties of bio-oils after esterifieation were improved significantly： the higher heating value approached 20. 08 and 18.33 MJ/kg, which improved 19.5% and 43.6%, respectively. The viscosity was decreased from 11.8 and 1.42 mm2/s to 3.77 and 1.12 mm2/s, respectively; and the moisture is about 23.7% and 28.4% （mass fraction）. The results of GC-MS show that organic acids in both bio-oils were successfully transformed into esters, primary ethyl acetate. Furthermore, the ion-exchanged resin could be convenient separated and reused, and would be a promising catalyst for upgrading of bio-oil.