生物油/生物柴油混合燃料的热稳定性

Thermal stability of bio-oil/bio-diesel mixture

为了考察生物油/生物柴油混合燃料的热稳定性,分析了该混合燃料在不同的存储温度和存储时间下组分物化性质的变化,并测试了存储前后该混合燃料的黏度、水分含量、酸度、平均分子质量等理化特性.实验结果表明:当存储温度为80℃,存储时间为180 h时,样品的含水量小于0.7%;黏度随存储温度的升高和存储时间的延长变化不大.利用FTIR和GPC分析了样品在存储过程中的化学变化.GPC结果表明,样品的分子质量有所增大,原因可能是在存储过程中发生了聚合或缩合反应.FTIR结果表明,生物油/生物柴油混合燃料中存在O—H伸缩振动、C—H伸缩振动和C=O伸缩振动,这些官能团吸收强度的增加说明在存储过程中发生了酯化、醚化等化学反应.

In order to understand the thermal stability of the bio-oil/bio-diesel mixture,the physicochemical properties of the mixture stored at different temperatures for different time were analyzed.The fuel properties of the bio-oil/bio-diesel mixture,such as viscosity,water content,acid number and average molecular weight,were also measured before and after aging.The experimental results show that the water content is less than 0.7% when the mixtures are aged at 80℃ for 180h.The viscosity changes slightly with the increase of aging temperature and aging time.The chemical changes during the storage were characterized by using the gel permeation chromatography（GPC） and the fourier transform infrared spectrometer（FTIR）.The results of the GPC exhibit a slight increase in the molecular weight,which is possibly due to some polymerization and condensation reactions during the storage.The results of the FTIR show the existence of O—H,C—H and stretch vibration.The increasing of the absorption intensity indicates the reaction of esterification during storage.