Instructions for starting and stopping operation of electric desalting of crude oil
1. Start operation of electric desalting
(1) Preparation
1 Notify the maintenance unit such as the electrical instrument to check the electrical, instrument and other equipment belonging to the electric desalting, and it is normal.
2 Check whether the electrode plate is installed in compliance with requirements.
3 Check whether the lead of each electrode plate is well connected, and whether the connection part of the lead and electrode rod and electrode plate is firm.
4 Check whether the insulation rod and the insulation hanger are properly installed. The insulation hanger is clean and free of dirt.
5 Check whether the sundries in the tank are cleaned.
6 Check whether the safety valve, pressure gauge, pressure gauge safety accessories, and the boundary check port and sampling port are complete and functional.
7 No-load test. All checks are normal, contact the electrical no-load test, no-load test is normal, you can contact and close the unit, seal the desalination tank manhole. During no-load test, the scene should set up a warning line, and there is a special person to monitor, and immediately pull the power off after the no-load test.
8. Learn the starting plan well, remove the blind boundary plate, and introduce water, electricity, steam and wind into the device.
(2) Through pressure test
After all the maintenance work is completed and the no-load test of the electrical system is normal, the manhole of the desalination tank is sealed, the relevant desalting process is corrected, and the pressure test is carried out.
When using steam to drill through and test the process of pre-stripping and post-stripping crude oil, it is necessary to open the electric desalting tank and open up the whole process from the outlet of the original oil pump to the initial distillation tower (flash tower). After the whole process is through, close the last valve before entering the initial distillation tower (flash tower) and start the steam pressure test. During the pressure test, check the whole process and contact the relevant units for treatment if any problem is found. At the same time, records should be made, after the pressure test, stop steam, and open the test pipeline at each low point to drain condensate.
The pressure test of the desalting tank, due to the high steam temperature during the test, the electrode rod and the insulation suspension are damaged, and the pressure test with water is generally recommended. Close the safety valve hand valve and the inlet and outlet valve of the desalting tank during the pressure test. After the pressure test is normal, the process is changed and the oil is loaded.
(3) Start oil pumping
All the processes of the electric desalting system are improved, and after the three levels of inspection are correct, the pump is opened to lead the crude oil to the desalting tank. With the desalting tank inlet valve and desalting auxiliary line valve, control the oil loading speed, when the level of the primary desalting tank is indicated, the oil loading speed should be slowed down appropriately, there is a special person on site to monitor the desalting empting situation, once the empting sees oil, immediately close the filling valve, so as not to run oil. During the oil loading process, pay attention to the liquid level of the initial distillation tower (flash tower), and keep the liquid level between 40% and 60%. This is used for secondary desalting of canned oil. After all desalted canned oil is finished, the desalted auxiliary line valve is closed and incorporated into the crude oil system for closed-circuit circulation.
(4) Use electric desalting system
After the closed circuit cycle is normal, contact the electricity and supply power to the desalting tank at all levels. Before the crude oil is switched over, the desalting water injection pump is started to fill water, and the water injection amount should be gradually increased from small to operational indicators. At the same time, start the demulsifier pump to inject demulsifier, and increase the amount of demulsifier to an appropriate range according to the properties of crude oil. In the meantime, timely contact the relevant control instrument of electric desalting, and check the use of each instrument in time, and check the instrument in time.
(5) Adjust the electric desalting operation
Control the desalting boundary, adjust and optimize the operating parameters of electric desalting to make the quality of the removed crude oil qualified.
2. Shutdown operation of electric desalting
(1) Preparation
First of all, carefully study the shutdown plan, and know the main points of the shutdown operation; Secondly, strengthen the backwashing operation of desalting, increase the backwashing intensity; Thirdly, it is necessary to arrange the use of desalting injection agents to avoid waste of chemical reagents.
(2) Stop work and withdraw oil
1 In order to improve the speed of electric desalting and oil withdrawal, the oil can be withdrawn in advance by primary desalting. 8h before the heating furnace is turned off, the secondary water injection is stopped, the purified water is injected into the first stage, the water injection amount of the primary desalting is increased, the primary desalting water is cut off, the desalting boundary is raised, the water is drained to the top of the primary desalting tank, and the primary desalting tank is cut out.
In the process of oil withdrawal, when the transformer trips, the transformer power off, when the device starts to drop, stop the injection of demulsifier.
3 After the atmospheric pressure furnace is turned off, all the electric desalting tanks are cut off, and the boundary of the secondary desalting tank is gradually raised until the water is seen at the top vent. The secondary desalting tank is cut off in time, and a large amount of water is strictly prohibited into the initial distillation tower (flash tower).
After the removal of the 4-point desalination tank, it is necessary to switch the water supply valve and sewage valve repeatedly, backwash each tank, wash the sludge at the bottom of the tank, so as to avoid the storage of oil in the tank and the bottom of the dirt.
5 Gradually release the water stored in the electric desalting tank, each electric desalting tank leads steam to the steam tank, generally the steam tank should be more than 24h, and the steam tank should be prevented from overtemperature in the tank to avoid damage to the insulation equipment.
6 After the steam tank is completed, open the manhole, natural ventilation, and deliver to the maintenance unit for maintenance after the gas analysis and explosive gas analysis are qualified.
