Deacidification Of Lube Base Oil

The main component of organic acids contained in crude oil is naphthenic acid, which may lead pipelines to corrosion and even leakage. In the same time, naphthenic acid is a very important and valuable raw material that can be extensively used in various areas of the industry processes and the daily life of people. The Deacidification method of alkali washing, electronic field refining and vitriol neutralization has some disadvantages such as easy forming emulsification of oil and water, generation of the sediment of alkali, serious pollution to environment. Some plants use the method of catalyze hydrogenation, but this method had some disadvantages also, for example, the investment is higher than others and wastes of the useful naphthenic acid, more over other methods are studying.Deacidification of the Base lubricating oil with low TAN is investigated in this paper theoretical and experimental. The complex depickling solvent was selected to remove the naphthenic acid and optimal condition of deacidification was decided. Ammonia, ion liquid and organic alkali and many others chemical agents were compared as depickling solvents, we found that a mixture of organic alkali and assistant solvent performed most well at last. The results indicated that the removal effect is higher than 70% and TAN(total acid number) is lower than 0.03mg KOH/g when the constituents ratio of depickling solvent was 0.8:5:10(A:C:D,v/v), A(organic amine), C, D (alcohol), reaction time 30min, the ratio of solvent to oil over and equal to 1:4, reaction temperature was in the range of 50～60℃, the rate of agitate 200～300r/min, and placing time no less than 120min. The apparent distribute coefficients were decided. A, C, D is 73.27, 5.72, 9.39 respectively. The condition of nitrogen removal was that distillation time more than 20min, vacuum 0.06～0.07MPa, distillation temperature 130～140℃, the content of nitrogen lower than 300μg/g. Commix depickling solvent was applied to continuous experiment in order to industrialize the deacidification process, and the constituents ratio of depickling solvent, conditions of continuous deacidification, the adaptability to other oils were researched. The results show that, when A:C was 3:7, the ratio of solvent to oil 1:5, the pump velocity 190L/h, reaction time 80℃, distillation time more than 40min, vacuum more than 0.07MPa, distillation temperature higher than 130～140℃, the TAN was lower than 0.03mg KOH/g and the content of nitrogen lower than 300μg/g. It is indicated that the deacidification process is suitable for not only 650~# oil, also 150~# oil and 500~# oil.