The Research Of Deacidification Of The Heavy Crude Oil With High Acid Number By Esterification

With the depth of oil exploration, the crude oil production of high acid value increased year by year. Very serious corrosion to the processing equipments are caused by high-acid crude oil during the course of processing, that effect the safety and the long-period operation of the oil refining equipment, therefore,the research of removal naphthenic acid from the high-acid crude oil became the focus of research projects.In view of the current status of crude oil deacidification research, five kinds of different catalysts were prepared in laboratories according to the composition of the catalyst with the method of solid mixing, and the various of catalysts were characterized. The means of characterization are: X-ray analysis, mensuration of surface area and the pore structure of catalyst, transmission electron microscopy scanning analysis and mechanical compressive strength.The crude oil was washed with water to remove the salines in oil and then was distlled to remove the water left. After above treatment, crude oil can enter the fixed-bed esterification reactor that is loaded with catalysts made in laboratory.The factors that impact of esterification, include: temperature, space velocity, the ratio of alcohol to oil and catalyst made with different ratio were investigated. The acid value of crude oil after esterification fluctuates between 0.4mgKOH/g and 0.6mgKOH/g, when the reaction temperature is excess 300℃, the space velocity 1h^-1 and the ratio of alcohol to oil 2w%.Compared esterification experiments of five kinds of catalysts at the same time, it can be summarized that: with the increase of the active component, the effects of esterification are getting better and better, but the mechanical compressive strength will gradually decrease and the degree of the catalyst bed blocking rate will increase. On the basis of maintaining a certain degree of mechanical compressive strength, the content of active component increase appropriately,the effect of catalytic esterification can be improved.An infrared analysis on the crude oil before and after esterification shows that esterification is fully occurred between naphthenic acid in crude oil and methanol through the fixed-bed catalytic esterification. The naphthenic acid has transformed and generated a large number of esters to achieve the purposes of deacidification from high-acid crude oil and verify that the esterification reaction is the principle of deacidification.The catalyst series made in laboratory have a long service life, and the deactivation catalyst can be regenerated by the way of calcination. The regenerated catalyst still has a high activity. The condition of on-line regeneration of the catalyst were also studied, and the effect of esterification catalyst after regeneration to the original fresh catalyst was studied.The experiments of the atmospheric and vacuum distillation of crude oil after esterification were simulated, the acid value of various components obtained by atmospheric and vacuum distillation is lower than the crude oil before the distillation, which indicates that acid number can not rise during the processing of atmospheric and vacuum distillation. The water vapor stripping experiments show that the water vapor can not make the acid number rise in the distillation.