Zhongguo youzhi (Apr 2023)
二聚酸抗磨剂对航空煤油润滑性的影响Effects of dimer acid antiwear agent on lubricity of jet fuel
Abstract
为考察二聚酸抗磨剂对加氢精制航空煤油润滑性的改善作用，同时验证不同二聚酸抗磨剂的改善效果，分别采用桐油、棉籽油及妥尔油酸为原料进行了二聚酸的合成与精制，利用液相色谱仪、红外光谱仪、核磁共振波谱仪等验证了桐油基、棉籽油基及妥尔油酸基二聚酸的分子结构，采用球柱润滑性评定仪（BOCLE）法和高频往复试验机（HFRR）法考察了3种不同原料来源的二聚酸对航空煤油润滑性的改善作用，用显微镜分析试验球的磨痕形貌，并提出抗磨机制。结果表明：随着二聚酸添加量的不断增大，磨痕直径、表面划痕及深度不断减小；在BOCLE法中，当二聚酸添加量为20 mg/L时，3种二聚酸均可使航空煤油润滑性磨痕直径从0.92 mm降到0.65 mm以下，满足GB 6537—2018《3号喷气燃料》要求；在HFRR法中，当二聚酸添加量为50 mg/L时，3种二聚酸均可使润滑性磨痕直径降到550 μm 以下，平均摩擦系数降到0.265以下，平均成膜率达到24%以上，且平均摩擦系数和平均成膜率的变化规律与二聚酸对航空煤油润滑性改善规律一致；制备的二聚酸均具有长碳链和羧基官能团，羧基通过强电负性吸附在金属表面，羧基之间的氢键以及非极性端通过范德华力等使二聚酸分子形成平行分子簇，进而在金属表面形成有效的润滑膜，阻止两摩擦副之间发生直接接触与摩擦。综上，3种二聚酸的润滑能力相当，均显示出良好的润滑性能。 In order to investigate the improvement of lubricity of dimer acid antiwear agents on jet fuel and verify the improvement effects of different dimer acids antiwear agents,dimer acids were synthesized and refined from tung oil, cottonseed oil and tall oil fatty acids, respectively, and their molecular structures were verified by liquid chromatography, FT-IR spectrometer and NMR spectrometer. The effects of cottonseed oil-based dimer acid, tung oil-based dimer acid and tall oil fatty acids-based dimer acid on the lubricity of jet fuel were investigated by BOCLE and HFRR tests. The wear scar morphology of the test ball was analyzed by measuring microscope and the antiwear mechanism was proposed. The results showed that with the increase of the dosage of dimer acid, the wear scar diameter, surface scratch and depth decreased. In BOCLE test, 20 mg/L dosage of dimer acids from three different raw materials could reduce the wear scar diameter of jet fuel from 0.92 mm to less than 0.65 mm ,meeting the requirement of GB 6537-2018 No.3 jet fuel. In HFRR test, when the dosage of three dimer acids was 50 mg/L, the wear scar diameter of lubricity and the average friction coefficient could be reduced below 550 μm and 0.265 respectively, and the average film formation rate could reach above 24%. The variation of the average friction coefficient and average film formation rate was consistent with the improvement rule of dimer acid on the lubricity of jet fuel. The dimer acids prepared had long carbon chains and carboxyl functional groups. The carboxyl group was adsorbed on the metal surface through strong electronegativity, the hydrogen bond with carboxyl groups and the non-polar end through Van Der Waals force made the dimer acid molecules form parallel molecular clusters, and then formed an effective lubrication film on the metal surface to prevent direct contact and friction between the two friction pairs. In conclusion, the three dimer acids have the uniform lubrication ability, and show good lubrication performance.
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