CO2-N2 enhanced crude electrostatic desalting method

Abstract

The invention discloses a CO2-N2 enhanced crude electrostatic desalting method and belongs to the technical field of crude oil pretreatment and deep dehydration. The method is characterized by comprising the following steps: 1) performing static mixing on crude oil and water; 2) injecting the mixture into a primary electrostatic desalting device for primary electrostatic desalting after fully mixing, and recovering residual CO2 gas; 3) injecting water again after the primary reaction so as to carry out secondary static mixing; 4) performing secondary electrostatic desalting after fully mixing,and recovering the residual N2 gas; 5) performing at least two-stage flushing, and discharging into a primary tower. According to the method disclosed by the invention, electrostatic desalting dehydration is enhanced by CO2-N2 micro-bubbles, and a manner of adding a demulsifier to perform crude oil dehydrating and desalting is completely replaced, so that the water-cut oil content and chemical oxygen demands (COD) in an electrostatic desalting tank can be obviously decreased, impurities in the crude oil are effectively removed, the water drop coalescence removal rate is obviously improved, the salt content and water-cut oil content of the dehydrated crude oil can be reduced, corrosion and scale of downstream equipment can be effectively retarded, and sewage treatment cost is reduced.

Description

Technical field [0001] A kind of CO 2 -N 2 An enhanced crude oil electric desalination method belongs to the technical field of crude oil pretreatment deep dehydration. Background technique [0002] For petroleum processing enterprises, before the crude oil enters the atmospheric and vacuum unit, it is usually required that the water content of the crude oil is less than 0.3% and the salt content is less than 3mg / L in order to stabilize production, prevent flushing, avoid equipment corrosion and scaling, and avoid Catalyst poisoning, etc. However, as major domestic oilfields have entered the late stage of exploitation, the extensive implementation of tertiary extraction technology has greatly increased the amount of chemical agents in the crude oil extraction process, the degree of crude oil emulsification and water content is very high, and the degree of heavy crude oil deterioration is serious. The traditional electric desalination process is facing great challenges. The elect...

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Problems solved by technology

However, as major oil fields in China have entered into the later stage of exploitation, the extensive implementation of three-stage recovery technology has led to a large increase in the amount of chemicals used in the crude oil extraction process, the degree of emulsification and water content of crude oil is very high, and the degree of heavy and poor quality of crude oil is serious

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