Study On The New Process Of Distillate Deacidification

In this paper, first of all, laboratory studies were carried out to remove Naphthenic acid from the second line of atmosphenic gas oil with ammonia method and alkali method. Single factor experiments were performed to determine the appropriate processing conditions range of deacidification, then orthogonal experiments were done to optimize the suitable conditions from single factor experiments, and to obtaine the degrees that four factors ( temperature, solvent-oil ratio, ethanol-water ratio, alkali concentration ) influenced on deacidification rate and Naphthenic acid recovery. It was found that, on terms of four factors influence on deacidification rate, same to extraction deacidification technology, the order of ammonia-method deacidification was solvent-oil ratio > alkali concentration > ethanol-water ratio > temperature. On terms of four factors influence on Naphthenic acid recovery, the order of ammonia method was temperature > solvent-oil ratio > alkali concentration > ethanol-water ratio, different from this method, the order of alkali method of ethanol-water ratio > alkali concentration > solvent-oil ratio > temperature.Besides these, according to optimizing process parameters of orthogonal experiments, under the circumstances without ethanol, continuous experiments were carried out to remove Naphthenic acid from raw oil with ammonia method and alkali method. It was found that, in the deacidification process of fiber-membrane-ammonia method, temperature of 50℃, solvent-oil ratio of 0.8:1, single-stage solvent-oil ratio of 0.4:1, ammonia content of 3%, the total Naphthenic acid recovery of 93.5%, the deacidification rate reached to 83.1%. In the deacidification process of fiber membrane-alkali method, temperature of 70℃, solvent-oil ratio of 0.7:1, single-stage solvent-oil ratio of 0.35:1, alkali concentration of 3%, the total Naphthenic acid recovery of 91.0%, the deacidification rate increased to 99.4. Compared to alkali method, the deacidification rate of ammonia method was relatively lower, without using strong acid and base in the experiments, decrease of"Three Wastes"greatly, lightenning burdens of wastewater treatment, so this method was relatively better. In order to improve ulteriorly deacidification rate, fiber membrane-ethanol-ammonia method deacidification experiments were carried out with ethanol, to sum up a conclusion that temperature of 50℃, solvent-oil ratio of 0.8:1, single-stage solvent-oil ratio of 0.4:1, ammonia content of 3%, ethanol-water ratio of 1.5:1, the deacidification rate could reach 92.9. A good result was got to verify the necessity of using fiber membrane-ethanol-ammonia method to remove Naphthenic acid from raw oil.