| With the improvement of environmental protection requirements,the production of diesel oil developed towards low sulfur and non-sulfur.With the removal of sulfur,some components with function of lubrication were also removed,the lubricating properties of diesel oil became worse,the diesel engine was abrased in using.Adding lubricant additives(anti-wear agent)in diesel oil was an effective way to reduce abrasion.The preparation of fatty ester and fatty acid ester anti-wear agent was introduced and its lubrication performance was evaluated in this paper.Soybean oleic acid,tall oleic acid and cottondseed oleic acid were used as raw material,the acid anti-wear agent was prepared by the multistage freezing filter method to refine oleic acid.The conditions of continuous freezing pressure filtration: filtration pressure is 0.2 ~ 0.4 MPa,filter cloth aperture is 25 ?m,freezing time is 20~24 hours,freezing times is 3,the first level freezing temperature 3~4?,the secondary freezing temperature-6 ~-8?,third stage freezing temperature-12 ~-15?.The freezing temperature of three kinds of oleic acid was slightly different,the temperature near freezing point was best.After purification,the yield of three kinds of oleic acid was over 80%.Three kinds of raw materials and products was characterized by gas chromatography,the results showed that the unsaturated fatty acid content in the raw material was about 90% and the content of unsaturated fatty acid in the products was more than 99%.Saturated fatty acids were removed,the cloud point and pour point were in line with the requirements of acid type anti-wear agent technology requirements.The HFRR method was used to evaluate the lubricating property of the three kinds of products,the results showed that the wear scar diameter conformed to the requirement of acid anti-wear agent of sinopec was lower than 420 ?m,when 150mg/kg was added in to two kinds of low sulfur diesel oil.The main ingredient of ester type anti-wear agent is unsaturated fatty acids polyol ester.The mixture of two and three oleic acid glycerides was synthesized by using oleic acid and glycerol as raw materials,p-toluene sulfonic acid as catalyst,toluene as water carrying agent.The effects of reaction time,amount of the catalyst,reaction temperature and molar ratio of alcohol to acid on the esterification were investigated,and the product structure was characterized by IR spectrum.The experimental results show that a more than 99.4 percent of esterification rate can reached when the molar ratio of alcohol to acid is 0.7:1,reaction temperature is 155 ~ 160 ?,reaction time is 9 h,thedosage of catalyst is 5% and the dosage of water carrying agent is 20%.The acid value of the product of esterification was less than 2 mg KOH/g.The antiwear properties of the product were evaluated by HFRR.The result showed that the wear scar diameter of two kinds diesel was decreased from 598 ?m and 580 ?m to 386.6 ?m and 377.4 ?m when 300 mg/kg was added into low sulfur diesel,and it accord with standard of sinopec.The character of anti-wear agent was stable,homemade anti-wear agent were added into two kinds of evaluated diesel.The viscosity,density,oxidation stability and low temperature fluidity of diesel oil were almost unchanged when the amount of additives were 150 mg/kg.The addition of ester anti-wear agent had no effects on the acidity of diesel oil,after added acid type anti-wear agent,the acidity of diesel oil increased obviously,the result was still lower than the national standard of 7mg KOH/100 mL. |
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