微拟球藻脂肪热解及对全组分制备生物油的影响

以酸水解法从微拟球藻中提取的粗脂肪为原料,在管式裂解炉中考察不同热解温度下脂肪单组分的热解规律及对微拟球藻全组分各相产率及生物油性能的影响。利用热重分析仪分别考察粗脂肪及全组分的热失重特性,并求出相应的动力学参数。结果表明,脂肪热解能够提高全组分热解有机相产率并改善油品性能。随着温度的升高,粗脂肪与全组分热解后的有机相产率及油品性能的变化趋势相同,且生物油性能均在600℃时达到最佳。经热解,粗脂肪中含氧化合物含量降低,脂肪烃含量显著增加。对比全组分热解,粗脂肪热解后的油品脱氧率及氢、碳元素比例更高,因而增加全组分中脂肪的含量能够促进油品性能的进一步提高。对粗脂肪及全组分的热重数据进行计算,发现两者均满足二级化学反应机理,粗脂肪、全组分的活化能与指前因子分别为64.34 k J/mol与2.94×105min-1,48.13 k J/mol与2.96×103min-1。

Pyrolysis of fat from Nannochloropsis sp.and its effect on bio-oil from pyrolysis of all components

The crude fat was used as raw material, which was extracted from Nannochloropsis sp. by acid hydrolyzation. The pyrolysis characteristic of crude fat and its effect on the yield of each phase and the properties of bio-oil were examined at different temperatures in a bench-scale fixed bed reactor. In addition, the thermogravimetric characteristics of crude fat and all components were studied by means of thermogravimetric analyzer, and corresponding kinetic parameters were determined. The results show that both the yield of organic phase and the properties of bio-oil which is produced from the pyrolysis of all components are enhanced by the pyrolysis of fat. Moreover, with an increase in temperature, the yield of organic phase and the properties of bio-oil from crude fat and all components have same varying trend, and their best properties are obtained at 600 ℃. The content of oxygenated compounds in the crude fat including alcohols, acids and esters decreases and that of aliphatic hydrocarbon severely increases after being pyrolyzed. Compared with the pyrolysis of all components, the deoxidizing ratio and the content of carbon and hydrogen elements in crude fat after being pyrolyzed are higher, therefore the performance could be further improved with the increase of fat in the Nannochloropsis sp.. According to the kinetic data, the pyrolysis of crude fat and all components follows the second order reaction mechanism. The pyrolysis activation energy and pre-exponential factor are 64.34 kJ/mol and 2.94×10⁵ min^-1 for crude fat, and 48.13 kJ/mol and 2.96×10³ min^-1 for all components.