Study On Deacidification Coupled Desalting Technology For Highly Acid Crude Oil

With the continuous development of global economy, a large number of petroleum resources are consumed, leading to a scarcity of conventional oil resources, in this context, the importance of high acid heavy crude oil is becoming increasingly apparent. Due to the high acid heavy crude oil poor nature, processing difficulties and other shortcomings leading to high cost of refining, oil refining enterprises are reluctant to processing this kind of crude, but at the same time, because in the international crude oil market, the price of crude oil with high acid is low, therefore, if we can find an efficient and environmental protection high acid crude oil processing technology will be to have a significant impact on China’s oil security strategy, and will significantly enhance the competitiveness of our oil refining enterprises.Firstly, the electric desalting process conditions of high acid heavy crude oil were deeply studied. The optimization results showed that, under the conditions of130℃temperature,10%water injection,20μg/g emulsion breaker dosage,～400/-800/-1200V/cm electric field intensity,12min/10min/8min residence time and2-stage desalting process, the salt and water mass fractions of the desalted crude oil were reduced to below3.0mg/L and0.30%respectively, which met the specifications of salt and water in the extra-heavy crude oil for the process unit.On this basis, this paper studied the acid removal of naphthenic acid from high acid crude oil. The research results showed that the depickling solvent adapted to karamay crude oil very well, the deacidification rate was high, and in the process of acid removal without emulsifying phenomenon. In optimal conditions, the acid value of crude oil after deacidification was0.23mgKOH/g, the deacidification rate was94.6%, all these numbers reached the standard of low acid crude oil, and at the same time, the salt content and water content of deacidified oil had both decreased.Based on depickling solvent has a certain ability to dissolve sodium chloride, calcium chloride and some other hydrochlorides from crude oil, this paper proposed a further research of coupling effect under the simulated conditions of electric desalting tank. The results showed that temperature and agent/oil ratio had a large impact on coupling effect, and under the conditions of3000μg/g dosage of sodium hydroxide,125℃temperature,2min mixing time,0.5agent/oil ratio,20min settling time, the acid value of crude oil after deacidification was0.08mgKOH/g, deacidification rate was98.1%, the salt content fell from11.5mgNaCl/L to8.0mgNaCl/L, the coupling effect was obvious.Finally, Paper studied the structure of the naphthenic acid from karamay crude oil by IR, mass spectrometry and some other analysis methods, the data showed that carbon number of naphthenic acid mainly existed between C7and C46, the number of fused ring was less, and carboxyl mainly exists in the form of monoacid.