微藻航空燃料的热氧化安定性与热沉

Thermal stability and heat sink of microalgae aviation fuels

航空燃料安定性和热沉对飞机和发动机工作可靠性、飞机飞行安全及战术性能的发挥有重要作用。利用热重-差热分析联用仪研究了2种典型微藻航油的热氧化安定性和热沉,并与标准航空喷气燃料RP-3进行了对比。结果表明:混合生物油的失重终点温度和最大失重点的温度与标准航空喷气燃料RP-3相比均向高温区移动。在失重区间内,除了物理热沉还有化学热沉的贡献。在热重曲线中定义了2个无量纲参数:引发温度和燃尽指数,引发温度表征起始裂解温度,燃尽指数表征沉积特性。2个参数结合可以较好地诠释燃料的热安定性和热沉。球等鞭金藻油高碳数烷烃在提高热沉基础上导致碳沉积的形成,但小球藻油在热沉提高的基础上,并没有形成碳沉积。说明通过有效控制高碳数烷烃分配比例增加其热沉并控制其积碳在理论和技术上是可行的。

The thermal stability and heat sink of aviation fuel play an important role in the reliability,safety and performance of aircraft and engine. Two types of typical microalgae aviation fuel were investigated to assess thermal stability and heat sink by thermo-gravimetric-differential scanning calorimetry in comparison with the standard turbine jetfuels RP-3. The results show that the temperatures of the end point and maximum weight loss point are higher than that of the standard turbine jetfuels RP-3,which indicates that heat sink includes both physical heat sink and chemical heat sink in weight loss interval. The thermo-gravimetric curve defines two dimensionless parameters including initiation temperature and burnout index,which represent the initial decomposition temperature and the deposition characteristics respectively. The combination of the two parameters can be used to assess the thermal stability and heat sink. Isochrysis based blend aviation fuel presented the carbon deposit with the increase of heat sink,while chlorella based blend aviation fuel did not present the carbon deposit with the increase of heat sink. The results indicate that optimizing the composition of alkane with high carbon number could increase heat sink and decrease carbon deposit. It is feasible both theoretically and technically.