离子交换树脂催化酯化生物油的试验研究

生物油黏稠、稳定性差、热值低、腐蚀性强,需要进行改质与品位提升,将生物油中的有机酸通过酯化的方法转化为中性的酯类可以改善生物油的性能。实验利用模型反应,筛选出了适合于生物油体系的732型和NKC-9型两种树脂作为酯化改质的催化剂。生物油和甲醇在间歇釜内以732和NKC-9为催化剂进行改质以后,酸值分别降低了88.54%和85.95%,表明生物油中的有机酸极大地转化为中性酯类。此外,热值分别提高了32.26%和31.64%,水分分别降低了27.74%和30.87%,密度均降低了21.77%,黏度降低均接近97%。732树脂固定床催化酯化生物油后,酸值降低了92.61%。加速陈化实验和铝片腐蚀性实验结果分别表明,改质生物油的稳定性和腐蚀性能得到了改善。

Experimental study on catalytic esterification of bio-oil by ion exchange resins

Upgradation of bio-oil before utilization is desirable to obtain high grade fuel because of its drawbacks like high viscosity, low heating value, poor stability and high corrosiveness. Organic acids in bio-oils can be converted to their corresponding esters by catalytic esterification and this greatly improved quality of bio-oils. We selected 732 and NKC-9 type ion exchanger resins as esterification catalysts for upgrading bio-oil. The catalytic activity was first investigated by model reaction first. The esterification of bio-oil with methanol was conducted in a batch reactor. Acid numbers of upgraded bio-oil on 732 resin and NKC-9 resin were lowered by 88.54% and 85.95% respectively, which represents the conversion of organic acids to neutral esters; the heating values increased by 32.26% and 31.64% respectively; the H2O contents decreased by 27.74% and 30.87% respectively; the densities were lowered by 21.77% for both and the viscosities fell by approximately 97%. A fixed bed reactor was used for continuous catalytic esterification of bio-oil by 732 resin and the acid number remarkably decreased by 92.61％. The accelerated ageing test showed improvement of stability and the aluminum strip corrosion test showed reduced corrosion rate of bio-oil after upgradation.