Block automatic oil treatment unit (UPN) of heater-treater type is designed for separation of oil producing well products and oil treatment according to the required quality standards. The unit is used for efficient heating, dehydration, and desalting of oil emulsions and preparation of commercial oil.
Due to versatile functionality, a UPN EOR unit can simultaneously replace several cleaning systems:
-
Dehydration of crude oil;
-
Its separation into oil and by-products;
-
Obtaining refined oil.
Operating principle of heater-treater type UPN
The oil and gas-water mixture enters the tank through an inlet assembly that directs the flow around the flame tubes to the lower section of the unit in order to prevent cold water from entering the flame tubes directly. The inlet assembly is equipped with a removable flow distributor manifold installed along the unit axis to prevent deposits in the intertube space of the flame tubes during operation of the unit with low oil water cut.
The flame tubes transfer heat through the walls and heat the oil and gas-water mixture, and the combustion products are discharged upwards through the chimney. The mixture heating temperature is monitored by a special sensor, the signal from which is also fed to the fuel gas inlet control valve.
Heating the oil and gas-water mixture achieves two goals:
1) the density difference between oil and water increases,
2) the viscosity of the oil decreases.
Both of these factors increase the rate of separation of the oil-gas-water mixture into oil and water. Oil, having a lower density, rises to the surface of the water phase. The oil level and the water-in-oil interface is automatically regulated and measured by means of level sensors that send a signal to the water discharge valve. The process also separates the gas, which is routed to the top of the device.
The heated oil-gas-water mixture enters the coalescence section. The coalescence section is equipped with coalescing plates that form narrow channels for the oil to pass through. Intensive deposition of enlarged water droplets occurs in the channels. The purified oil overflows through the baffle and enters the oil collection section.
The separated oil from the process unit is transferred to the control unit, where the oil level in the dewatering compartment of the process unit is regulated with a control valve. A flow meter is installed on the oil outlet line; a crude oil moisture meter is installed on the oil bypass line, which monitors the water content in the treated oil. The water separated from the oil is distributed in the lower part of the unit and is taken out of the process unit, after which it enters the control unit, where the level of phase separation in the unit is regulated with the control valves and a level sensor.
The gas released from the oil-gas-water mixture is removed from the device through a nozzle installed above the prepared oil collection section. In order to use associated gas as fuel for the flame tube burners, the control unit includes a gas purification unit from dripping moisture, gas pressure regulator, shut-off, cut-off, and safety valves for burner supply.
Washing water under high pressure is supplied through slot nozzles in two levels: some nozzles direct jets of water above the inner surface of the device wall, and the others are directed below to the center of the apparatus. Thus, the walls of the device are flushed on two levels.
Main parts of UPN
The unit considered in this section is a horizontal cylindrical device with elliptical bottoms, V = 115m3 with internal devices, heater with two block burners installed in two flame tubes, with two smoke pipes, piping, shut-off and control valves, instrumentation, most of which are placed in the valve block box with a complete life support system. The unit is mounted on two saddle supports.
A control unit is installed on one end side of the device, which includes pipelines for discharge of separated water, purified oil outlet pipeline, gas outlet pipeline with shut-off and control valves, instrumentation, and fuel gas cleaning unit from droplet moisture. Two covered block burners are installed on the opposite side. Automation system cabinets are installed in the operator's room.
Process-based oil temperature and the phase residence time in the device depend on the physical and chemical properties of the separated media.
Advantages of the heater-treater automated oil treatment unit (UPN):
-
Multifunctionality — the unit can perform multiple oil refining functions;
-
Primary raw material separation in unlimited volume regardless of pressure;
-
Low water concentration (less than 5%) due to upgraded filtration systems;
-
Increased level of fire safety;
-
Automatic safety control system.