Microwave crude oil demulsification oil-water three-phase separation metering device and series connection and parallel connection system

Abstract

The microwave crude oil demulsification oil-water three-phase separation metering device comprises a vertical separation tank, the upper portion of the vertical separation tank is connected with a gas chamber, and the top of the gas chamber is connected with a gas outlet pipeline; a liquid inlet, a water outlet and an oil outlet are further connected to the side wall of the vertical separation tank, a liquid inlet inner vertical pipe is further arranged in the vertical separation tank, and the lower end of the liquid inlet inner vertical pipe is connected with the liquid inlet; the upper end of the liquid inlet inner vertical pipe and the side wall of the vertical separation tank below the oil outlet are respectively connected with a microwave radiation heating device; crude oil which is sprayed out and needs to be output from a tank is heated at an outlet, namely the upper end, of a liquid inlet inner vertical pipe and the lower end of an oil outlet, heating temperature rise and demulsification dehydration are achieved, demulsification oil-water separation of the crude oil is achieved by means of the two characteristics of the heat effect and the non-heat effect of microwaves, oil and water are separated in a natural precipitation mode, and the oil-water separation effect is achieved. And heating can be easily controlled to stop after power failure, and thermal inertia and pollution-free carbon emission are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of oil-gas-water separation in crude oil treatment, and particularly relates to a microwave crude oil demulsification oil-water three-phase separation metering device and series and parallel systems thereof. Background Art

[0002] During the oilfield production process, the main task is to dehydrate the oil-gas-water mixture produced from oil wells to meet the specified water content requirement of commercial crude oil (≤0.5%). In the crude oil gathering and transportation system of oil production plants, the separation of oil, gas, and water mostly adopts large horizontal three-phase separators for centralized treatment. To achieve rapid separation, it is necessary to heat up the crude oil and add demulsifiers. Firstly, for heating up, a heat transfer medium conduction type gas or electric heating furnace is used. The combination of the three-phase separator and the heating furnace has a large volume, with problems such as slow and uneven heat conduction, thermal inertia that is not easy to control, easy scaling in electric heating, poor safety of gas heating furnaces, large maintenance workload, and environmental pollution caused by gas emissions.

[0003] Secondly, although adding demulsifiers can promote the separation of oil and water, the resulting secondary pollution caused by residual suspended solids increases the load on the water treatment system. The oil-containing sewage produced from the oil-water separation does not meet the standards and needs to be deoiled, which brings a series of problems to the crude oil gathering, transportation, and storage. In severe cases, it can cause pollution to soil, surface water, and groundwater. The centralized treatment using three-phase separators has defects such as poor response to large fluctuations in the incoming liquid volume, poor separation effect, and unqualified water quality. If the water separated from the crude oil reaches 100% pure water and the water quality standard can meet the requirements for direct discharge or reinjection into the formation, and the water content of the produced crude oil ≤0.5% is the best separation state.

[0004] Designing and producing a separator that is efficient, time-saving, clean, pollution-free, flexible to use, and easy to control the temperature, and can directly produce qualified oil and water is a difficult problem urgently needed to be solved in the oilfield. Summary of the Invention

[0005] The purpose of the invention is to provide a microwave crude oil demulsification oil-water three-phase separation metering device and series and parallel systems thereof to directly produce qualified oil and water.

[0006] The purpose of the invention is achieved by the following technical means. A microwave crude oil demulsification oil-water three-phase separation metering device includes a vertical separation tank. An air chamber is connected above the vertical separation tank, and an air outlet pipeline is connected to the top of the air chamber. The side wall of the vertical separation tank is also connected with a liquid inlet, a water outlet, and an oil outlet. The liquid inlet and the water outlet are located at the bottom of the side wall and are opposite to each other, and the oil outlet is located at the top of the side wall. An inner liquid inlet riser is also arranged in the vertical separation tank, and the lower end of the inner liquid inlet riser is connected to the liquid inlet. The upper end of the inner liquid inlet riser and the side wall of the vertical separation tank below the oil outlet are respectively connected with a first microwave radiation heating device and a second microwave radiation heating device. It further includes a controller which is electrically connected to two radiation heating devices. The gas chamber is connected to the vertical separation tank through a gas chamber connection flange.

[0007] At the top of the gas chamber, i.e., at the inlet of the gas outlet pipeline, a demister is connected. A pressure transmitter is also connected outside the gas chamber, and a constant pressure valve is connected on the gas outlet pipeline.

[0008] The oil outlet is higher than the liquid inlet, the liquid inlet is higher than the water outlet, and the oil outlet is higher than the upper end of the inner vertical liquid inlet pipe.

[0009] An aqueous probe is further arranged inside the vertical separation tank, and the aqueous probe is electrically connected to the controller.

[0010] The aqueous probe is lower than the upper end of the inner vertical liquid inlet pipe.

[0011] The water outlet is connected to a water outlet pipeline through a flange. A water outlet control valve and a water outlet flowmeter are arranged on the water outlet pipeline, and both the water outlet control valve and the water outlet flowmeter are electrically connected to the controller.

[0012] The oil outlet is a pipeline extending outwardly from the side wall of the vertical separation tank. An aqueous sensor and a temperature transmitter are connected to the pipeline, and both the aqueous sensor and the temperature transmitter are electrically connected to the controller.

[0013] A microwave crude oil demulsification oil-water separation series system includes a plurality of microwave crude oil demulsification oil-water separation devices, namely a primary oil separator, a secondary oil separator, and a water separator. The oil outlet of the primary oil separator is connected to the inlet of the secondary oil separator, and the oil outlets of the secondary oil separator and the water separator are both connected to an external oil pipeline; The water outlets of the primary oil separator and the secondary oil separator are both connected to the inlet of the water separator, and the water outlet of the water separator is connected to an external water pipeline; The gas outlet pipelines of the primary oil separator, the secondary oil separator, and the water separator are all connected to an external gas pipeline; The secondary oil separator and the water separator do not have inner vertical liquid inlet pipes, and the inlets of the secondary oil separator and the water separator are both located above their respective first microwave radiation heating devices.

[0014] A microwave crude oil demulsification oil-water separation parallel system includes a plurality of microwave crude oil demulsification oil-water separation series systems. After the external incoming oil pipeline is branched, it is connected to the liquid inlets of the primary oil separators of each microwave crude oil demulsification oil-water separation series system.

[0015] The beneficial effects of the present invention are as follows: By heating the ejected crude oil and the crude oil to be output in the tank at the outlet of the inner vertical liquid inlet pipe, that is, the upper end, and at the lower end of the oil outlet, heating and temperature increase as well as demulsification and dehydration are achieved. By utilizing the two major characteristics of the thermal effect and non-thermal effect of microwave, demulsification and oil-water separation of crude oil are realized. Then, through the method of natural precipitation, the oil and water are separated. There is no need for a heating furnace and adding demulsifying agent, and the heating is easy to control, stopping immediately when the power is cut off, without thermal inertia and no pollution and carbon emissions. Brief Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of a microwave crude oil demulsification and oil-water separation device; Figure 2 It is a schematic structural diagram of a series system for microwave crude oil demulsification and oil-water separation; Figure 3 It is a schematic structural diagram of a parallel system for microwave crude oil demulsification and oil-water separation; In the figure, 1 is a vertical separation tank, 101 is a liquid inlet, 102 is an inner vertical liquid inlet pipe, 1031 is a first microwave radiation heating device, 1032 is a second microwave radiation heating device, 104 is a gas chamber connection flange, 105 is a demister, 106 is a pressure transmitter, 107 is a constant pressure valve, 108 is a water content sensor, 109 is a temperature transmitter, 110 is a water content probe, 111 is a water outlet flange, 112 is a water outlet control valve, 113 is a water outlet flowmeter, 114 is a controller, 115 is a gas chamber, 116 is an oil outlet, 117 is a gas outlet pipeline; The present invention will be further described in detail below with reference to the drawings and embodiments. Specific Embodiments

[0017] A microwave crude oil demulsification and oil-water three-phase separation and metering device includes a vertical separation tank 1. A gas chamber 115 is connected above the vertical separation tank 1, and a gas outlet pipeline 117 is connected to the top of the gas chamber 115; The side wall of the vertical separation tank 1 is also connected with a liquid inlet 101, a water outlet 111 and an oil outlet 116. The liquid inlet 101 and the water outlet 111 are located at the bottom of the side wall and are opposite in position, and the oil outlet 116 is located at the top of the side wall. An inner vertical liquid inlet pipe 102 is also arranged in the vertical separation tank 1, and the lower end of the inner vertical liquid inlet pipe 102 is connected with the liquid inlet 101; A first microwave radiation heating device 1031 and a second microwave radiation heating device 1032 are respectively connected to the upper end of the inner vertical liquid inlet pipe 102 and the side wall of the vertical separation tank 1 below the oil outlet 116; It also includes a controller 114, and the controller 114 is electrically connected to the first microwave radiation heating device 1031 and the second microwave radiation heating device 1032. As Figure 1As shown in the figure, a vertical stainless steel pipe with a pipe diameter of DN150mm is used as the vertical separation tank 1, with a height of 2000mm. The incoming crude oil is input from the liquid inlet 101 at the bottom of the pipe. Inside the liquid inlet, there is a liquid inlet inner vertical pipe 102 welded. The height of the liquid inlet inner vertical pipe 102 is half of the total length of the stainless steel pipe 1. The first microwave radiation heating device 1031 is installed at the upper part of the liquid inlet inner vertical pipe 102. The crude oil coming in from the liquid inlet inner vertical pipe 102 flows upward, and the first microwave radiation heating device 1031 just radiates and heats it for demulsification. The microwave radiation heating device is not limited to one. For example, there can be multiple first microwave radiation heating devices 1031, and multiple first microwave radiation heating devices 1031 can be arranged upward or relatively arranged; The second microwave radiation heating device 1032 heats the crude oil below the oil outlet 116 to further heat up and demulsify and dehydrate.

[0018] The gas chamber 115 is connected to the vertical separation tank 1 through a gas chamber connection flange 104.

[0019] At the top of the gas chamber 115, that is, at the inlet of the gas outlet pipeline 117, a demister 105 is connected. Outside the gas chamber 115, a pressure transmitter 106 is also connected. A constant pressure valve 107 is also connected to the gas outlet pipeline 117.

[0020] The gas chamber 115 is connected to the vertical separation tank 1 through a gas chamber connection flange 104. A pressure transmitter 106 and a constant pressure valve 107 are installed at the gas outlet. A demister 105 is set at the inlet of the gas outlet to ensure that there is no moisture in the gas entering the gas outlet pipeline 117.

[0021] The oil outlet 116 is higher than the liquid inlet 101, the liquid inlet 101 is higher than the water outlet 111, and the oil outlet 116 is higher than the upper end of the liquid inlet inner vertical pipe 102.

[0022] An aqueous probe 110 is also provided inside the vertical separation tank 1, and the aqueous probe 110 is electrically connected to a controller 114.

[0023] The aqueous probe 110 is lower than the upper end of the liquid inlet inner vertical pipe 102.

[0024] The water outlet 111 is connected to a water outlet pipe through a flange. A water outlet control valve 112 and a water outlet flowmeter 113 are provided on the water outlet pipe. Both the water outlet control valve 112 and the water outlet flowmeter 113 are electrically connected to the controller 114.

[0025] The height of the water-containing probe 110 can be adjusted by adjusting the length of the support rod. Initially, the height of the water-containing probe 110 is adjusted to 300 mm above the water outlet, and a water outlet control valve 112 is provided at the water outlet. Due to the density difference between oil and water, the water in the oil settles naturally by gravity. The crude oil with water after microwave radiation and heat demulsification sinks by gravity, and the low-density crude oil floats and flows through the oil outlet. In this way, pure water gradually settles at the lower part of the separator. The signals of the sensor and the control valve are both connected to the controller 114, and the functions of signal acquisition and valve control are realized through the controller 114.

[0026] The oil outlet 116 is a pipe connected to the side wall of the vertical separation tank 1 and extending outward. A water content sensor 108 and a temperature transmitter 109 are connected to the pipe, and both the water content sensor 108 and the temperature transmitter 109 are electrically connected to the controller 114.

[0027] A water content sensor 108 and a temperature transmitter 109 are installed at the upper oil outlet to monitor the water content and temperature at the oil outlet 116.

[0028] By installing flow meters at the water outlet, gas outlet, and oil outlet, the flow rate is measured while the three-phase separation is carried out.

[0029] The microwave thermal effect heats up the crude oil. The principle of microwave heating is volume heating. The polar molecules in the medium are arranged in a directional and repeated manner along the electric field direction under the action of the electric field torque after an external alternating electric field. The stronger the external electric field, the stronger the molecular friction. The microwave frequency of 2.45 GHz generates 2.45 billion frictions per second, so the heat generation speed is very fast and the heating is uniform inside and outside at the same time. Water is an excellent polar molecule, and the crude oil produced from oil wells is a mixture of oil, gas, and water. The water exists in the form of a fully emulsified emulsion (W / O, O / W), which is more conducive to the molecular volume heating method of microwaves. Microwave heating is easy to control, stopping immediately when the power is cut off, without thermal inertia and no carbon emissions.

[0030] The non-thermal effect of microwaves can change the molecular structure of crude oil, break the long carbon chain solid component molecules in the crude oil into low-carbon chain gas and liquid components, increase the fluidity of the crude oil, and reduce the viscosity of the crude oil and make the emulsified crude oil easier to demulsify and dehydrate without obvious temperature rise. The water molecules in the crude oil have a stronger ability to absorb microwaves than oil molecules. The water droplets expand, and the interfacial film between oil and water becomes thinner under the internal pressure and is easy to break. At the same time, the microwave radiation forms a high-frequency changing electromagnetic field, which can desorb the asphaltenes and resins in the crude oil from the interface, destroy the Zeta potential at the oil-water interface, and the water droplets are easy to collide and coalesce, resulting in oil-water separation. The stronger the radiation power, the more obvious the effect. The demulsification effect is very obvious after 1 - 2 minutes of microwave radiation.

[0031] Crude oil is ejected upward from the liquid inlet 101 through the inner liquid inlet riser 102 from the first microwave radiation heating device 1031. The first microwave radiation heating device 1031 heats and radiates the flowing crude oil. Under the action of microwaves, water molecules gradually flocculate and coalesce to form large liquid droplets. Under the action of gravity, the large liquid droplets sink. The greater the water content of the large liquid droplets, the faster the sedimentation. At the bottom of the vertical separation tank 1 is pure free water with a water content of 100%. The thickness of the free water also accumulates higher and higher. When the water content probe 110 detects a water content of 100%, the height from its lower part to the water outlet 300 mm is pure water. At this time, the water outlet control valve 112 is opened, and the water outlet flowmeter 113 detects the instantaneous flow rate FT. The outer diameter of the inner liquid inlet riser 102 is d. By calculation, the discharge time Tp of the pure water at the bottom 300 mm height is as follows: Tp = 0.3 * 3.14 * (0.075 * 0.075 - d * d) / FT, where 0.075 is the radius of the stainless steel pipe of the vertical separation tank 1.

[0032] When the valve opening time reaches Tp, control to close the water outlet control valve 112. Repeat this control process repeatedly to monitor whether the water content WO value at the oil outlet reaches 0.5%. If it can reach less than 0.5%, continuously control this process to achieve the goal. If the WO value never reaches 0.5%, then adjust the height of the water content probe 110 to increase by 200 mm. The pure water discharge time Tp is: Tp = 0.5 * 3.14 * (0.075 * 0.075 - d * d) / FT, Each time, more pure water is discharged to create a larger oil-water separation space. The control process is the same as above. The height of the water content probe 110 cannot be higher than the height of the inner liquid inlet riser 102. Drain water according to this control method until the water content WO value at the oil outlet reaches less than 0.5%. At this time, there is no need to adjust and a dynamic balance state is maintained.

[0033] As Figure 2 shown, a microwave crude oil demulsification oil-water separation series system includes multiple microwave crude oil demulsification oil-water separation devices, namely a primary oil separator, a secondary oil separator, and a water separator. The oil outlet 116 of the primary oil separator is connected to the inlet of the secondary oil separator. The oil outlets 116 of the secondary oil separator and the water separator are both connected to the external oil pipeline; The water outlets 111 of the primary oil separator and the secondary oil separator are both connected to the inlet of the water separator. The water outlet 111 of the water separator is connected to the external water pipeline; The gas outlet pipelines 117 of the primary oil separator, the secondary oil separator, and the water separator are all connected to the external gas pipeline; The secondary oil separator and the water separator do not have the inner liquid inlet riser 102. The inlets of the secondary oil separator and the water separator are both located above their respective first microwave radiation heating devices 1031.

[0034] If the water content probe 110 still cannot meet the requirement of water content less than 0.5% even when its height reaches that of the liquid inlet inner riser 102, consider adding a secondary oil separator and a water separator. If the secondary oil separator is not enough, more stages can be added continuously.

[0035] The primary oil separator, secondary oil separator, and water separator are all microwave crude oil demulsification oil-water separation devices. The secondary oil separator and water separator have the same structure as the primary oil separator except that they do not have the liquid inlet inner riser 102.

[0036] The gas outlet pipelines 117 of the three separation devices are all connected to the external gas pipeline to discharge the separated gas; The oil output from the primary oil separator enters the secondary oil separator for further separation, and the oil separated by the secondary oil separator is discharged through the oil outlet 116; The water output from the primary and secondary oil separators is sent to the water separator. The oil separated by the water separator is discharged through the oil outlet 116, and the separated water is discharged through the water outlet 111.

[0037] The difference among the three is that the inlet of the secondary oil separator is set in the upper middle part, the inlet of the water separator is set in the upper part, the height of the water content probe 110 at the corresponding bottom is adjusted, and correspondingly, the position of the first microwave radiation heating device 1031 is also changed according to the inlet.

[0038] As Figure 3 shown, a microwave crude oil demulsification oil-water separation parallel system includes multiple microwave crude oil demulsification oil-water separation series systems. After the external incoming oil pipeline is branched, it is connected to the liquid inlet 101 of the primary oil separator of each microwave crude oil demulsification oil-water separation series system.

[0039] For a joint station with a large processing capacity, according to the single-unit processing capacity, multiple units are used in parallel simultaneously. The separation main unit is used, and the incoming liquid is branched and converged according to the incoming liquid volume situation.

[0040] After the upstream incoming liquid is branched by the total branch and convergence mechanism, it is branched into #1 incoming liquid, #2 incoming liquid, etc., and is respectively input into their respective microwave crude oil demulsification oil-water separation series systems. Several microwave crude oil demulsification oil-water separation series systems form a large parallel system.

[0041] Among them Figure 2 and Figure 3 , the oil collecting pipe of the n# separator, the gas outlet of the n# separator, and the water outlet of the n# separator represent the oil outlet, gas outlet, and water outlet of each series system, and can be converged onto a unified output pipeline. For example, the gas outlets of all series systems are uniformly connected to a gas outlet pipeline for external output, and the same applies to the oil outlet and water outlet.

Claims

1. A microwave crude oil demulsification oil-water-gas three-phase separation and metering device, characterized in that: It includes a vertical separation tank (1). An air chamber (115) is connected above the vertical separation tank (1), and an air outlet pipeline (117) is connected to the top of the air chamber (115). The side wall of the vertical separation tank (1) is also connected with a liquid inlet (101), a water outlet (111) and an oil outlet (116). The liquid inlet (101) and the water outlet (111) are located at the bottom of the side wall and are opposite in position. The oil outlet (116) is located at the top of the side wall. An internal liquid inlet riser (102) is also arranged in the vertical separation tank (1), and the lower end of the internal liquid inlet riser (102) is connected with the liquid inlet (101). The upper end of the internal liquid inlet riser (102) and the side wall of the vertical separation tank (1) below the oil outlet (116) are respectively connected with a first microwave radiation heating device (1031) and a second microwave radiation heating device (1032). It also includes a controller (114), and the controller (114) is electrically connected to the two radiation heating devices (103).

2. The microwave crude oil demulsification oil-water-gas three-phase separation and metering device according to claim 1, characterized in that: The air chamber (115) is connected to the vertical separation tank (1) through an air chamber connection flange (104).

3. A microwave crude oil demulsification oil-water-gas three-phase separation metering device according to claim 1 or 2, characterized in that: At the top of the air chamber (114), that is, at the inlet of the air outlet pipeline (117), a demister (105) is connected. A pressure transmitter (106) is also connected outside the air chamber (114), and a constant pressure valve (107) is connected to the air outlet pipeline (117).

4. A microwave crude oil demulsification oil-water-gas three-phase separation and metering device according to claim 1, characterized in that: The oil outlet (116) is higher than the liquid inlet (101), the liquid inlet (101) is higher than the water outlet (111), and the oil outlet (116) is higher than the upper end of the internal liquid inlet riser (102).

5. A microwave crude oil demulsification oil-water-gas three-phase separation and metering device according to claim 1 or 4, characterized in that: An aqueous content probe (110) is also arranged in the vertical separation tank (1), and the aqueous content probe (110) is electrically connected to the controller (114).

6. A microwave crude oil demulsification oil-water-gas three-phase separation and metering device according to claim 5, characterized in that: The aqueous content probe (110) is lower than the upper end of the internal liquid inlet riser (102).

7. A microwave crude oil demulsification oil-water-gas three-phase separation metering device according to claim 1, characterized in that: The water outlet (111) is connected with a water outlet pipeline through a flange. A water outlet control valve (112) and a water outlet flowmeter (113) are arranged on the water outlet pipeline. Both the water outlet control valve (112) and the water outlet flowmeter (113) are electrically connected to the controller (114).

8. A microwave crude oil demulsification oil-water-gas three-phase separation metering device according to claim 1, characterized in that: The oil outlet (116) is a pipeline extending outwardly connected to the side wall of the vertical separation tank (1). An aqueous content sensor (108) and a temperature transmitter (109) are connected to the pipeline. Both the aqueous content sensor (108) and the temperature transmitter (109) are electrically connected to the controller (114).

9. A series system for microwave crude oil demulsification and oil-water separation, characterized in that: It includes a plurality of microwave crude oil demulsification oil-water separation devices, namely a primary oil separator, a secondary oil separator and a water separator. The oil outlet (116) of the primary oil separator is connected to the inlet of the secondary oil separator, and the oil outlets (116) of the secondary oil separator and the water separator are both connected to an external oil pipeline. The water outlets (111) of the primary oil separator and the secondary oil separator are both connected to the inlet of the water separator, and the water outlet (111) of the water separator is connected to an external water pipeline. The air outlet pipelines (117) of the primary oil separator, the secondary oil separator and the water separator are all connected to an external gas pipeline. The secondary oil separator and the water separator do not have an internal liquid inlet riser (102), and the inlets of the secondary oil separator and the water separator are both above their respective first microwave radiation heating devices (1031).

10. A parallel system for microwave crude oil demulsification and oil-water separation, characterized in that: It includes multiple microwave crude oil demulsification and oil-water separation series systems. After the external incoming oil pipeline is branched, it is connected to the liquid inlet (101) of the first-stage oil separator of each microwave crude oil demulsification and oil-water separation series system.

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