掺混与组分优化提高费托喷气燃料热氧化安定性的机理研究

The Mechanism of Improving Thermal Stability of FT Jet Fuel by Blending and Component Optimization

由于喷气燃料组成受限于原油组成与炼制工艺,高热氧化安定性能喷气燃料逐步走向合成燃料与石油基喷气燃料的掺混与组分优化。通过静态、动态试验对比分析了费托喷气合成燃料(FT)与石油基喷气燃料(RP-3)的热氧化安定性,并采用DTG-DSC同步测试对比了热氧化性和蒸发性。研究发现FT与RP-3掺混比对热氧化沉积量、引发温度的影响是非线性的,对燃料的蒸发性能影响是线性的。研究表明单环烃(甲基环戊烷与甲基环己烷),与双环烃(四氢萘和十氢萘)都不同程度提高FT喷气燃料的热氧化安定性。其中甲基环戊烷、十氢萘在较宽掺混浓度范围内可显著提高FT燃料热氧化安定性。但甲基环己烷与四氢萘只在较窄低浓度掺混区域显著提高FT燃料热氧化安定性。通过层析浓缩获得的热氧化产物解析机理,发现甲基环戊烷提高热氧化安定性能的是由于其氧化产物不易生成具有苯环结构的积碳母体且具有较好的溶剂作用。十氢萘提高热氧化安定性能机理是氧化产物具有良好供氢能力而且其热裂解产物结构稳定。甲基环己烷与四氢萘由于其自身氧化产物不稳定,导致掺混浓度增加提高热氧化安定性的性能下降。

As the composition of petroleum-based jet fuel is confined by its crude oil and refining process, alternative aviation fuel becomes to undertake the composition optimization and blending tech-nology of jet fuel with high thermal oxidation stability. The thermal oxidation stability of FT alterna-tive jet fuel was compared with conventional petroleum-based jet fuel by static and dynamic tests, and the thermal oxidation trend and evaporation performance were investigated by DTG-DSC. The influence of the blending ratio is nonlinear on the weight of thermal oxidation deposition and in-itiation thermal oxidation temperature while is linear on the evaporation performance. The results show that monocyclic hydrocarbons (methylcyclopentane and methylcyclohexane) and dicyclic hydrocarbons (decaline and tetraline) can improve the thermal oxidation stability of FT jet fuel. Among them, the thermal oxidation stability of FT fuel can be significantly improved by a wide mixing concentration range of methyl-cyclopentane and decaline. However, methylcyclohexane and tetraline only significantly improved the thermal oxidation stability of FT fuel in a narrow region with low concentration blending. The methyl-cyclopentane can improve thermal oxidation stability because its oxidation products are not easy to form carbon deposit precursor with benzene ring structure and it possesses the capability of solvent action. The oxidation products derived from decalene still have good hydrogen supply capacity and the structure is stable in the pyrolysis region. When the blending ratios of methyl cyclohexane and tetraline are increasing, the oxidation products derived from those can further pyrolyze and thus decrease the ability of enhancements of thermal oxidation stability.