氧清除剂用于增强吸热型碳氢燃料热氧化安定性

热氧化安定性是吸热型碳氢燃料贮存和使用过程中评价燃料品质的重要性质之一,反映了喷气燃料在260℃以下组分受溶解氧影响的程度和燃料氧化反应进行的深度。为评价氧清除剂,选用一种实验室自制的吸热型燃料,运用加速氧化法,配合滴定、红外光谱、粒度分布和JFTOT等测试方法对燃料的基础物性和热氧化安定性进行评估,比较了三苯基膦(TPP)、二环己基苯基膦(DCP)和1,2,5-三甲基吡咯(TMP)三种氧清除剂对吸热型碳氢燃料自氧化过程的影响,并确定了测试范围内的最佳添加量。结果显示,三种氧清除剂的添加对燃料的组成和基础物性无明显影响;燃料中的溶解氧浓度随添加量增加不断下降,最大可降低溶氧浓度31.95 mg/m~3;加速氧化后,样品的过氧化值和酸值均不同程度下降;胶团粒径分布趋向于更小粒径方向; JFTOT测试结果均满足国标规定。总体上,氧清除剂的添加均能有效提升燃料的热氧化安定性,三者的最优添加量均为质量分数1.5×10~(-5),作用效果优劣顺序为TMPTPP≈DCP。

Enhancement of thermal oxidation stability of endothermic hydrocarbon fuels by using oxygen scavengers

Thermal oxidation stability is one of the important properties for evaluating fuel quality during the storage and use of endothermic hydrocarbon fuels; it reflects the extent to which jet fuel is affected by dissolved oxygen below 260℃ and the depth of oxidation reaction. In this work, the basic properties and thermal stability of endothermic hydrocarbon fuels with oxygen scavengers were evaluated by accelerated oxidation method combined with titration, infrared spectroscopy, particle size distribution and JFTOT. The effect of three oxygen scavengers, viz., triphenylphosphine (TPP), dicyclohexylphenylphosphine (DCP) and 1,2,5-trimethylpyrrole (TMP), on the auto-oxidation process of endothermic hydrocarbon fuels were comparatively investigated and the optimal addition amount within the test range was determined. The results show that there is no significant change in the fuel composition and basic physical properties after the addition of oxygen scavengers. The dissolved oxygen concentration in the fuel decreases with the increase of the amount of oxygen scavengers, and the maximum drop is 31.95 mg/m³. The peroxide value and acid value of the samples show different degrees of decline after accelerated oxidation, and the particle size distribution of the micelles tends to be smaller. The JFTOT test results can meet the national standards. In general, the addition of oxygen scavenger can effectively improve the thermal oxidation stability of the fuel; the effect of three oxygen scavengers follows the order of TMP >TPP ≈ DCP and the optimal addition amount is 1.5×10^-5 (by mass fraction).