A Research On Crude Oil Electrical Desalting Equipment With Intelligent Response

Due to the constraints of the mining environment and the production process, crude oil contains water and salts inevitable. The salts of crude oil severely harm the refinery production. They can form scaling, reduce heat transfer efficiency and increase energy consumption. They can corrode equipment and affect production safety. They can cause catalyst failure, reduce product quality, increase production cost and pollute the environment. But, the crude oil into refinery is affected by various unfavorable factors of influence and increasingly becomes heavier and poorer quality. Moreover, the refinery requires in-depth processing technology of crude oil for improving efficiency and reducing the cost, and the traditional equipment has not well met these needs. So, this topic research the crude oil electrical desalting equipment with intelligent response.The author first studied the mechanism of high pressure field to crude oil emulsion and desalination processes. Combined with data analysis results of the field and laboratory, we found the mixing intensity of crude oil and infusing water directly determined the desalting efficiency when multistage desalination. But, the traditional mechanical mixing method can not meet this need because of low efficiency. So, the author put forward his own electric field adjustment scheme according to the theory of electrical dispersion and electrostatic mixed.Electrical desalting system generally includes three parts: electrical desalting power with intelligent response, transformer and desalination cans. The main work is the electrical desalting power design. First, using our accumulated technical advantages on crude oil dehyd ration power supply with alternating rectangular-wave, we design the main circuit structure of power supply. The power supply has two working mode: manual and automatic. The automatic specially is designed for desalination process, and has designed intelligent response system in the voltage control circuit. In this system, MCU intelligently responds to the user's requirements for setting working parameters, controls D/A transition chip and output analog voltage control signal. This control signal input the feedback input of TL494, PWM control chip. Through it, we can control the IGBT module's duty cycle of the half bridge converter, and then realize the adjustment of desalination electric field. In addition, the MCU is equipped with external data storage, which is used to ensure not losing parameters'information when the power is interrupt. The data communication between the MCU and the computer is achieved by the RS232 data interface.Using VC++6.0 programming language, we designed a computer window for the user's operating conveniently.The system's hardware and software were completed, then we did desalination experiment. the effect of multistage desalting is good and the efficiency is high, after desalination, the salt rate is below 5mg/L and good crude oil is below 3mg/L, the system can satisfy the customer's requirement. Based on the same design principle, the writer designed high-power electrical desalting equipment and have did field experiment. Field experiment indicates that the equipment can work stably and reliably, the effect of desalting and dehydration is good, water content can decline to 0.1～0.2% and the salt rate fall below 5mg/L. It meets the requirement of the design and has a significant effect on energy saving. There is a good application prospect.