Skid-mounted plate heat exchanger automatic backwashing system and method based on oil and gas scene

Abstract

The invention provides an automatic backwashing system and method for a skid-mounted plate heat exchanger based on an oil and gas scene, and the system comprises a controller, a power backwashing device, a natural circulation backwashing electric gate valve, and a backwashing valve. The natural circulation backwashing electric gate valve is connected to the plate heat exchanger, the backwashing valve is respectively connected to the plate heat exchanger and the power backwashing device, and the controller is connected with the plate heat exchanger according to the pressure and temperature information of each pipeline of the plate heat exchanger. Opening and closing of the natural circulation backwashing electric gate valve and the backwashing valve are controlled, so that natural circulation backwashing and power circulation backwashing are carried out. According to the skid-mounted plate heat exchanger automatic backwashing system and method based on the oil and gas scene, the cleaning effect can be improved while manpower and material resources are saved, the risk of each link is reduced, and the service life of equipment is prolonged.

Description

Technical Field

[0001] This invention relates to the field of petrochemical machinery technology, and in particular to an automatic backflushing system and method for skid-mounted plate heat exchangers based on oil and gas scenarios. Background Technology

[0002] Pure titanium plate heat exchangers possess characteristics such as high heat transfer coefficient, small footprint, expandability, and corrosion resistance, making them widely used as core heat exchange equipment in oilfield waste heat recovery systems. The efficient and stable operation of plate heat exchangers directly affects the heat exchange efficiency of the entire waste heat system, while ensuring the temperature requirements for crude oil transportation and the energy efficiency of produced water recovery, effectively reducing crude oil transportation costs and achieving energy conservation and emission reduction goals.

[0003] During the operation of a plate heat exchanger, the softened water from the heat pump exchanges heat with the medium through counter-current flow within the heat exchanger, transferring heat from the high-temperature side to the low-temperature side. Different medium sides present specific problems: the crude oil side is affected by mechanical impurities, flocculent matter, associated gas, and other factors; the produced water side is affected by silt, impurities, wax deposits, scale, and oil sludge adhering to the walls. These factors lead to a decrease in the heat transfer coefficient and reduced economic efficiency, while also causing flow channel blockage and increased pressure resistance, directly impacting the reliability and safety of medium delivery. To ensure the efficient and stable operation of the plate heat exchanger, timely cleaning is necessary.

[0004] The traditional procedure is as follows: 1. Operators first shut down the heat exchanger on-site, isolating softened water and media by closing the manual gate valves on the process pipeline; 2. Then, drain the remaining softened water and media in the plate heat exchanger through the drain valves at the bottom of the heat exchanger inlet and outlet pipelines, and the collected hazardous waste is disposed of by a professional company; 3. Manually disassemble the plate heat exchanger, transport the plates to a professional cleaning facility, and clean both sides of each plate individually by means of chemical soaking and high-pressure water rinsing; 4. The cleaned plates are transported back to the site and installed one by one into the heat exchanger frame; 5. Finally, after passing the water pressure test, the original manual gate valves for softened water and media flow are opened to restore the plate heat exchanger to operation.

[0005] Because disassembly and cleaning involves manpower, hazardous waste disposal, disassembly and transportation, and hydrostatic testing, this cleaning method is complex, time-consuming, and resource-intensive, while also posing environmental risks. The frequency of disassembly and cleaning varies depending on the characteristics of the project's medium. Furthermore, the cumulative number of disassembly and cleaning operations can cause irreversible damage to the heat exchanger plates and sealing strips, leading to a reduction in heat exchange area, decreased heat exchange efficiency, and frequent replacement of sealing strips. This further increases the cost of disassembly and cleaning, reducing the overall heat exchange efficiency and economic viability of the waste heat recovery system.

[0006] Chinese patent application CN202220700953.9 discloses an automatic backwashing system for heat exchangers. The system includes a heat exchanger, an electric four-way valve, and a filter valve. One side of the electric four-way valve is connected to the heat exchanger's inlet and outlet water pipes, while the other side is connected to one end of the filter valve and the inlet water pipe. The other end of the filter valve is connected to the outlet water pipe, and an electric drain valve is located at the bottom of the filter valve. A drain pipe is connected to the bottom of the electric drain valve. A differential pressure transmitter A is installed between the heat exchanger's inlet and outlet water pipes. A differential pressure transducer B is connected in parallel with the filter valve. The system also includes a control cabinet, and the electric four-way valve, filter valve, electric drain valve, differential pressure transmitter A, and differential pressure transmitter B are all connected to the control cabinet. This system can prevent heat exchanger blockage and maintain heat exchange efficiency. However, this application addresses the issues of clean water and impurities in the system, and cannot solve the problems of water-bearing crude oil, produced water, and oil and scale buildup in oilfield scenarios.

[0007] Chinese patent application CN202221725024.X discloses an automatic backwashing system for plate heat exchangers, including a heat exchanger and backwashing equipment. The backwashing equipment includes a control box, an electric four-way valve, a differential pressure transmitter, a water pump, a filter, an electric on / off valve, and an electric drain valve. The heat exchanger medium inlet is connected to port D of the electric four-way valve via a pipeline, the heat exchanger medium outlet is connected to port B of the electric four-way valve via a pipeline, port A of the electric four-way valve is connected to the system medium outlet via a pipeline, and port C of the electric four-way valve is connected to the system medium inlet via a pipeline. The differential pressure transmitter is connected to both the heat exchanger medium inlet and outlet. This application installs a four-way valve on the side of the plate heat exchanger, replacing four large shut-off butterfly valves with a four-way valve. This simplifies the structure, eliminates the need for complex piping arrangements, saves cost and space, and makes wiring and piping more convenient. However, this application is not specifically for oil and gas scenarios and cannot solve the problems of water-containing crude oil, produced water, and oil and scale buildup in the system.

[0008] Chinese patent application CN202321611432.7 discloses a backwashing device for a plate heat exchanger, comprising a heat exchanger body. A water outlet pipe is installed through the right side of the outer wall of the heat exchanger body, and a scale treatment structure is connected below the water outlet pipe. A water inlet pipe is connected to the bottom of the scale treatment structure. An exhaust gas treatment structure is provided on the side of the scale treatment structure, with an air inlet pipe connected to the top of the exhaust gas treatment structure and an air outlet pipe connected to the bottom. A storage structure is provided inside the scale treatment structure, including a pipe cover and a material distribution net. The storage structure facilitates the injection of chemical agents, which, when added directly to the water, prevent scale crystallization and improve the backwashing effect of the heat exchanger body. This application is applicable to scale treatment and is not very suitable for oilfield scenarios.

[0009] The existing technologies described above are significantly different from the present invention and have failed to solve the technical problem we want to address. Therefore, we have invented a new automatic backflushing system and method for skid-mounted plate heat exchangers based on oil and gas scenarios. Summary of the Invention

[0010] The purpose of this invention is to provide an automatic backwashing system and method for skid-mounted plate heat exchangers based on oil and gas scenarios, which realizes programmed operation of automatic backwashing of different plate heat exchangers to solve the adverse effects of existing cleaning methods.

[0011] The objective of this invention can be achieved through the following technical measures: an automatic backwashing system for skid-mounted plate heat exchangers in an oil and gas scenario. This automatic backwashing system includes a controller, a powered backwashing device, a natural circulation backwashing electric gate valve, and a backwashing valve. The natural circulation backwashing electric gate valve is connected to the plate heat exchanger, and the backwashing valve is connected to both the plate heat exchanger and the powered backwashing device. The controller controls the opening and closing of the natural circulation backwashing electric gate valve and the backwashing valve based on the pressure and temperature information of each pipeline of the plate heat exchanger, thereby performing natural circulation backwashing and powered circulation backwashing.

[0012] The objective of this invention can also be achieved through the following technical measures:

[0013] There are two of each of the natural circulation backwash electric gate valve and the backwash valve. The two natural circulation backwash electric gate valves are located between the inlet and return liquid lines of the plate heat exchanger. One end of the first backwash valve is connected to the return liquid line of the plate heat exchanger and the other end is connected to the inlet end of the power backwash device. One end of the second backwash valve is connected to the inlet liquid line of the plate heat exchanger and the other end is connected to the return water end of the power backwash device.

[0014] The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes four electric gate valves, four pressure transmitters, and four temperature transmitters. The four electric gate valves, the four pressure transmitters, and the four temperature transmitters are respectively located on the inlet liquid line, the return liquid line, the return water line, and the inlet water line of the plate heat exchanger.

[0015] The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes an ultrasonic flow meter. The first electric gate valve, the first pressure transmitter, and the first temperature transmitter of the four electric gate valves are connected to the inlet liquid line of the plate heat exchanger. The second electric gate valve, the second pressure transmitter, and the second temperature transmitter of the four electric gate valves are connected to the return liquid line of the plate heat exchanger. The third electric gate valve, the third pressure transmitter, and the third temperature transmitter of the four electric gate valves are connected to the return water line of the plate heat exchanger. The fourth electric gate valve, the fourth pressure transmitter, the fourth temperature transmitter, and the ultrasonic flow meter are connected to the inlet water line of the plate heat exchanger.

[0016] The controller calculates and detects that the pressure difference transmitted by the first pressure transmitter and the second pressure transmitter is greater than 0.05 MPa. Based on the temperature and flow values ​​transmitted by the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has decreased to below 85% of the normal average value. Then, it controls the two natural circulation backwash electric gate valves to open and the first and second electric gate valves to close, so that the inlet becomes the outlet and the outlet becomes the inlet, and natural circulation backwashing is performed.

[0017] The controller calculates and detects that the pressure difference transmitted by the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value based on the temperature and flow values ​​transmitted by the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, or that the natural circulation backwashing duration has reached 24 hours. Then, it controls the first electric gate valve and the second electric gate valve to open, and the two natural circulation backwashing electric gate valves to close, that is, the natural circulation backwashing system is shut down, and normal operation is restored. The system will not control the switching of natural circulation backwashing for 48 hours.

[0018] The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a first chemical tank electric gate valve and a second chemical tank electric gate valve. The first chemical tank electric gate valve is located between the first chemical tank and the power backwashing device, and the second chemical tank electric gate valve is located between the second chemical tank and the power backwashing device.

[0019] The power backwashing device includes a heating module, a circulating water pump, and a water tank. Depending on the characteristics of the crude oil or the produced water, the electric gate valve of the first or second chemical tank is opened to add the corresponding chemical agent to the water tank. The heating module heats the substances in the water tank, and the circulating water pump pumps the heated chemical mixture or clean water into the plate heat exchanger for soaking and backwashing. The heating module can be powered by diesel, an electric motor, or electricity.

[0020] The controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.10 MPa. Based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has decreased to below 70% of the normal average value. Then, the power circulation backwashing process is started.

[0021] When the power circulation backwashing process is started, the electric gate valve of the first chemical tank or the electric gate valve of the second chemical tank is opened according to the medium type of the plate heat exchanger, and the corresponding chemical agent is added to the water tank. After a certain period of time, the electric gate valve of the first chemical tank or the electric gate valve of the second chemical tank is closed.

[0022] After the first or second medicine tank electric gate valve is closed, the power backwashing device is activated, the first and second backwashing valves are opened, and the first and second electric gate valves are closed. The medicine mixture enters the plate heat exchanger through the first backwashing valve and returns to the water tank through the second backwashing valve, performing power circulation backwashing on the plate heat exchanger.

[0023] The controller calculates and detects that the pressure difference transmitted by the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa. Based on the temperature values ​​transmitted by the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value. Alternatively, if the duration of the power backflushing reaches a predetermined value, the first electric gate valve and the second electric gate valve open, and the first backflushing valve and the second backflushing valve close. The power backflushing device stops and returns to normal operation.

[0024] The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a water tank drain valve connected to the drain line of the power backwashing device and a water tank water supply valve connected to the water supply line of the power backwashing device. After the power backwashing device stops, the water tank drain valve is opened and closed when the water level in the tank drops to 0 cm. The water tank water supply valve is opened and closed when the water level in the water tank reaches 100 cm. The system will not control the switching of power circulation backwashing for a predetermined time.

[0025] The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a check valve connected between the power backwashing device and the first backwashing valve to prevent the medium, i.e., oil or produced water, from flowing into the power backwashing device.

[0026] The objective of this invention can also be achieved through the following technical measures: an automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios. This automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios employs an automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios, comprising:

[0027] Step 1: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.05 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has decreased to less than 85% of the normal average value based on the temperature values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, natural circulation backwashing is performed.

[0028] Step 2: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value based on the temperature values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, or the natural circulation backwashing duration has reached 24 hours, then the natural circulation backwashing process is closed.

[0029] Step 3: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.10 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has decreased to less than 70% of the normal average value based on the temperature values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, then the power circulation backwashing process is started.

[0030] Step 4: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value based on the temperature values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, or when the power backflushing duration reaches a predetermined value, the power circulation backflushing process stops and normal operation is restored.

[0031] The objective of this invention can also be achieved through the following technical measures:

[0032] In step 1, two electric gate valves for natural circulation backwashing are opened, and the first and second electric gate valves are closed, so that the inlet becomes the outlet and the outlet becomes the inlet, and natural circulation backwashing is performed.

[0033] In step 2, the first and second electric gate valves are opened, and the two natural circulation backwash electric gate valves are closed, that is, the natural circulation backwash is turned off, the normal operation is restored, and the natural circulation backwash switching is no longer controlled within 48 hours.

[0034] In step 3, when the power circulation backwashing process is started, the first or second chemical tank electric gate valve is opened according to the medium type of the plate heat exchanger, and the corresponding chemical agent is added to the water tank. After a certain period of time, the first or second chemical tank electric gate valve is closed.

[0035] After the first or second medicine tank electric gate valve is closed, the power backwashing device is activated, the first and second backwashing valves are opened, and the first and second electric gate valves are closed. The medicine mixture enters the plate heat exchanger through the first backwashing valve and returns to the water tank through the second backwashing valve, performing power circulation backwashing on the plate heat exchanger.

[0036] In step 4, the first and second electric gate valves are opened, and the first and second backwash valves are closed; the power backwashing device stops and returns to normal operation.

[0037] In step 4, after the power backwashing device stops, the water tank drain valve is opened, and closed when the water level in the tank drops to 0 cm. The water tank water supply valve is opened, and closed when the water level gauge in the tank reaches 100 cm. The power circulation backwashing switch is no longer controlled within a predetermined time.

[0038] This invention presents an automatic backflushing system and method for skid-mounted plate heat exchangers in an oil and gas scenario. For each plate heat exchanger, it utilizes both natural circulation and dynamic backflushing pipelines. Appropriate reagents are added based on the characteristics of the medium, effectively improving the backflushing effect, increasing the heat exchange efficiency and duration of the plate heat exchanger, and improving system energy efficiency. This truly achieves energy conservation and emission reduction, while also reducing the labor intensity of operators. Therefore, this invention effectively overcomes some practical problems in existing technologies, thus possessing high utilization value and practical significance. This automatic backflushing system and method for skid-mounted plate heat exchangers in an oil and gas scenario can improve cleaning effectiveness, reduce risks at each stage, and extend equipment lifespan while saving manpower and resources. Attached Figure Description

[0039] Figure 1 This is a structural diagram of a specific embodiment of the automatic backflushing system for skid-mounted plate heat exchangers based on an oil and gas scenario according to the present invention.

[0040] Figure 2 This is a flowchart of an automatic backflushing method for skid-mounted plate heat exchangers based on an oil and gas scenario, according to a specific embodiment of the present invention. Detailed Implementation

[0041] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0043] like Figure 1 As shown, Figure 1 This is a structural diagram of the automatic backflushing system for skid-mounted plate heat exchangers based on an oil and gas scenario according to the present invention. The automatic backflushing system for skid-mounted plate heat exchangers based on an oil and gas scenario includes a controller, a powered backflushing device, a first electric gate valve JZ1 connected to the inlet pipeline of the plate heat exchanger, and a first pressure transmitter PIT. 101 First temperature transmitter TIT 101 The first natural circulation backflushing electric gate valve FC1, the second electric gate valve JZ2 connected to the return liquid line of the plate heat exchanger, and the second pressure transmitter PIT 102 Second temperature transmitter TIT 102 The second natural circulation backwash electric gate valve FC2, the third electric gate valve HS1 connected to the return water line of the plate heat exchanger, and the third pressure transmitter PIT 202 Third temperature transmitter TIT 202 The fourth electric gate valve LS1 and the fourth pressure transmitter PIT are connected to the inlet water pipeline of the plate heat exchanger. 201 Fourth temperature transmitter TIT 201 Ultrasonic flow meter FE1, power backwashing device, water tank drain valve PS1 connected to the drain line of the power backwashing device, water tank water supply valve BS1 connected to the water supply line of the power backwashing device, first backwash valve DF1, second backwash valve DF2, third backwash valve DFQ1, fourth backwash valve DFQ2, first medicine tank electric gate valve HX1 and first medicine tank electric gate valve HX2.

[0044] One end of the first backflushing valve DF1 is connected to the return liquid line of the plate heat exchanger, and the other end is connected to the inlet of the power backflushing device. One end of the second backflushing valve DF2 is connected to the inlet liquid line of the plate heat exchanger, and the other end is connected to the return water line of the power backflushing device. One end of the third backflushing valve DFQ1 is connected to the inlet of the power backflushing device, and the other end is connected to the return liquid line of other heat exchangers.

[0045] One end of the fourth backwash valve DFQ2 is connected to the return water end of the power backwash device, and the other end is connected to the inlet pipeline of other heat exchangers.

[0046] The first medicine tank electric gate valve HX1 is located between the chemical reagent tank 1 and the power backwashing device.

[0047] The second medicine tank electric gate valve HX2 is located between the chemical agent tank 2 and the power backwashing device.

[0048] The controller controls the opening and closing of each valve based on the received pressure, temperature and flow information, thereby controlling the automatic backwashing system of the skid-mounted plate heat exchanger based on the oil and gas scenario to perform natural circulation backwashing and dynamic circulation backwashing.

[0049] The following are several specific embodiments of the application of the present invention.

[0050] Example 1

[0051] In a specific embodiment 1 of the present invention, the normal operating system flow is as follows: the medium and softened water undergo counter-current convection on both sides of the heat exchanger plates through inlet and outlet pipes connected to the plate heat exchanger. Electric gate valves (JZ1, JZ2, LS1, HS1) and temperature transmitters (TIT) are respectively installed on the inlet and outlet pipes. 101 TIT 102 TIT 201 TIT 202 ), pressure transmitter (PIT) 101 PIT 102 PIT 201 PIT 202 ), Ultrasonic flow meter (FE1), used to start and stop heat exchange equipment and monitor the status of various media parameters.

[0052] The plate heat exchanger is a high-efficiency heat exchanger composed of a series of metal plates with a certain corrugated shape stacked together. Rectangular channels are formed between the plates, and heat exchange between the media occurs through convection.

[0053] The natural circulation backwashing process involves opening the electric gate valves (FC1, FC2) connected to the incoming and outgoing liquid pipelines, and closing the electric gate valves (JZ1, JZ2) in normal operation. This achieves the goal of turning the inlet into the outlet and the outlet into the inlet. The medium fluid enters the heat exchanger through the return liquid pipeline and flows out from the incoming liquid pipeline, circulating in reverse within the heat exchanger to flush away the soft scale adhering to the plate surface and the inlet filter screen.

[0054] The power circulation backwash process involves a power circulation backwash pipeline installed on each plate heat exchanger. This pipeline connects to the power backwash device and is equipped with a check valve ZH1 to prevent the medium (oil or produced water) from flowing into the backwash device when not flushing. The inlet of the power circulation backwash pipeline connects the return pipeline of the plate heat exchanger to the backwash device, while the return pipeline connects the inlet pipeline of the plate heat exchanger to the backwash device. This achieves the goal of the inlet becoming the outlet and the outlet becoming the inlet. Both the inlet and return ends are equipped with electric gate valves (DF1, DF2), which are automatically opened and closed by a controller, initiating the power circulation backwash process.

[0055] The power backflushing device connects multiple plate heat exchangers in parallel through the cleaning pipeline. By opening the inlet and outlet electric gate valves (DF1, DF2 or DFQ1, DFQ2) on the cleaning pipeline of the corresponding heat exchanger, the cleaning fluid is pumped into the plate heat exchanger for power circulation backflushing.

[0056] The power backwashing device has a water supply line and a drainage line, and both the water supply line and the drainage line are equipped with electric gate valves (BS1, PS1).

[0057] The power backflushing device includes a heating module, a circulating water pump, and a water tank. The heating module heats the water in the tank. Based on the characteristics of the crude oil or produced water, appropriate chemicals are added to the tank. The circulating water pump then pumps the heated chemical mixture or clean water into a plate heat exchanger for soaking and backflushing. The heating module can be powered by diesel, an electric motor, or electricity.

[0058] In this embodiment, the power backwashing device uses a combination of a diesel generator, a circulating water pump, and a water tank. After the diesel fuel performs its work, exhaust fumes are emitted. This device incorporates a coiled exhaust duct within the cleaning water tank. The diesel generator exhaust fumes heat the circulating water in the tank via the coil before being discharged into the atmosphere. The water in the cleaning tank is also heated. Increased water temperature improves the cleaning effect. The controller selects appropriate chemicals to add to the water tank based on the characteristics of the crude oil or produced water. The circulating water pump then pumps the heated chemical mixture or clean water into the plate heat exchanger for soaking and backwashing.

[0059] The backwashing system also includes a controller connected to the power backwashing device and backwashing valves (DF1, DF2 or DFQ1, DFQ2). By calculating the heat transfer coefficient of the plate heat exchanger, if the pressure difference of the plate heat exchanger reaches 0.05 MPa and the heat transfer coefficient decreases to 85% of the average heat exchanger coefficient, the natural circulation backwashing process is initiated until the pressure difference of the plate heat exchanger drops below 0.02 MPa and the heat transfer coefficient recovers to above 95%, or the duration reaches 24 hours. Then, normal operation resumes, and natural circulation backwashing is not performed again within 48 hours. If the pressure difference of the plate heat exchanger reaches 0.10 MPa and the heat transfer coefficient decreases to 70% of the average heat exchanger coefficient, the power circulation backwashing process is initiated until the pressure difference of the plate heat exchanger recovers to below 0.02 MPa and the heat transfer coefficient recovers to above 95%, or the duration reaches 6 hours. Then, normal operation resumes, and power circulation backwashing is not performed again within 120 hours. If the heat exchanger's heat transfer coefficient still cannot recover to 70% of the average heat transfer coefficient after natural circulation backwashing and power circulation backwashing, then traditional manual disassembly and cleaning will be performed.

[0060] Example 2

[0061] In a specific embodiment 2 of the present invention, the controller calculates the heat transfer coefficient:

[0062] The heat exchange capacity of this plate heat exchanger is calculated using inlet and outlet temperature transmitters for softened water and an ultrasonic flow meter.

[0063] Q = C × M × ΔT

[0064] Where Q represents the heat exchange;

[0065] C is the specific heat capacity of softened water at this temperature;

[0066] M is the mass of softened water flowing through per unit time, M=ρ×V=ρ×Q×t=Q; where ρ is the density of softened water, t is the unit time, and Q is the flow rate of softened water;

[0067] ΔT is the temperature difference between the inlet and outlet of the softened water, i.e., ΔT = T 201 -T 202 .

[0068] The basic formula for heat transfer is Q = K × A × ΔT. m Calculate the heat transfer coefficient of the heat exchanger:

[0069]

[0070] Where K is the heat transfer coefficient;

[0071] Q represents the heat exchange rate;

[0072] A represents the heat exchange area of ​​the plate heat exchanger;

[0073] ΔT m The logarithmic mean temperature difference between the fluids on both sides of the plate heat exchanger is given by T. 101 It is the inlet temperature on the heat source side, T 102 Heat source side outlet temperature, T 201 Inlet temperature on the cold source side, T 202 It is the outlet temperature on the cold source side.

[0074] Right now

[0075] Combining the above two points, the heat transfer coefficient of the plate heat exchanger under this condition can be obtained.

[0076]

[0077] Example 3

[0078] In a specific embodiment 3 of the present invention, the automatic backflushing system and method for skid-mounted plate heat exchangers based on oil and gas scenarios includes the following steps:

[0079] Please see Figure 1 Under normal production conditions, the incoming liquid medium is heated or heated by the heat pump softened water on the opposite side of the plate heat exchanger, and then discharged through the return pipeline. Electric gate valves JZ1 and JZ2 are open, while the others are closed.

[0080] Step 1: When the control system calculates and detects PIT 101 With PIT 102 When the pressure difference reaches 0.05 MPa or more, and the heat transfer coefficient of the plate heat exchanger drops to below 85% of the normal average value, the FC1 and FC2 electric gate valves will open automatically, and the JZ1 and JZ2 electric gate valves will close automatically, so that the inlet becomes the outlet and the outlet becomes the inlet, and natural circulation backwashing is performed.

[0081] Step 2: When the control system calculates and detects PIT 101 With PIT 102 When the pressure difference returns to below 0.02 MPa and the heat transfer coefficient of the plate heat exchanger returns to above 95% of its normal average value, or when the natural circulation backwashing duration has reached 24 hours, then the electric gate valves JZ1 and JZ2 will automatically open, and the electric gate valves FC1 and FC2 will automatically close. This means the natural circulation backwashing system will be shut down, returning to normal operation, and will not be controlled for natural circulation backwashing switching again within 48 hours.

[0082] Step 3: When the control system calculates and detects PIT 101 With PIT 102If the pressure difference reaches 0.10 MPa or more, and the heat transfer coefficient of the plate heat exchanger drops to below 70% of the normal average value, then the power circulation backflushing process will be started.

[0083] Depending on the medium type in the plate heat exchanger, the HX1 or HX2 electric gate valve opens to add the appropriate chemical agent to the water tank, and the HX1 or HX2 electric gate valve closes after 60 seconds.

[0084] After the HX1 or HX2 electric gate valve is closed, the interlocked diesel generator and circulating water pump will start automatically, the DF1 and DF2 electric gate valves will open automatically, and the JZ1 and JZ2 electric gate valves will close automatically. The chemical mixture enters the plate heat exchanger through DF1 and returns to the water tank through DF2, performing a power circulation backwash on the plate heat exchanger.

[0085] Step 4: When the system detects PIT 101 With PIT 102 When the pressure difference returns to below 0.02 MPa and the heat transfer coefficient of the plate heat exchanger returns to above 95% of its normal average value, or when the power backflushing duration reaches 6 hours, the JZ1 and JZ2 electric gate valves will automatically open, and the DF1 and DF2 electric gate valves will automatically close. The circulating water pump will automatically stop after 10 seconds, and the diesel generator will automatically stop after another 10 seconds, returning to normal operation. 600 seconds after the diesel generator stops, the water tank drain valve PS1 will automatically open and close when the water level in the tank drops to 0 cm. The water supply valve BS1 will automatically open and close when the water level gauge in the tank reaches 100 cm, and will not be controlled to switch to power circulation backflushing for 120 hours.

[0086] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0087] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

Claims

1. An automatic backflushing system for skid-mounted plate heat exchangers in oil and gas scenarios, characterized in that, The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios includes a controller, a powered backwashing device, a natural circulation backwashing electric gate valve, and a backwashing valve. The natural circulation backwashing electric gate valve is connected to the plate heat exchanger, and the backwashing valve is connected to both the plate heat exchanger and the powered backwashing device. The controller controls the opening and closing of the natural circulation backwashing electric gate valve and the backwashing valve based on the pressure and temperature information of each pipeline of the plate heat exchanger, thereby performing natural circulation backwashing and powered circulation backwashing.

2. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 1, characterized in that, There are two of each of the natural circulation backwash electric gate valve and the backwash valve. The two natural circulation backwash electric gate valves are located between the inlet and return liquid lines of the plate heat exchanger. One end of the first backwash valve is connected to the return liquid line of the plate heat exchanger and the other end is connected to the inlet end of the power backwash device. One end of the second backwash valve is connected to the inlet liquid line of the plate heat exchanger and the other end is connected to the return water end of the power backwash device.

3. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 2, characterized in that, The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes four electric gate valves, four pressure transmitters, and four temperature transmitters. The four electric gate valves, the four pressure transmitters, and the four temperature transmitters are respectively located on the inlet liquid line, the return liquid line, the return water line, and the inlet water line of the plate heat exchanger.

4. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 3, characterized in that, The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes an ultrasonic flow meter. The first electric gate valve, the first pressure transmitter, and the first temperature transmitter of the four electric gate valves are connected to the inlet liquid line of the plate heat exchanger. The second electric gate valve, the second pressure transmitter, and the second temperature transmitter of the four electric gate valves are connected to the return liquid line of the plate heat exchanger. The third electric gate valve, the third pressure transmitter, and the third temperature transmitter of the four electric gate valves are connected to the return water line of the plate heat exchanger. The fourth electric gate valve, the fourth pressure transmitter, the fourth temperature transmitter, and the ultrasonic flow meter are connected to the inlet water line of the plate heat exchanger.

5. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 4, characterized in that, The controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.05 MPa. Based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has decreased to below 85% of the normal average value. Then, it controls the two natural circulation backwash electric gate valves to open, and the first electric gate valve and the second electric gate valve to close, so that the inlet becomes the outlet and the outlet becomes the inlet, and natural circulation backwashing is performed.

6. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 5, characterized in that, The controller calculates and detects that the pressure difference transmitted by the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa. Based on the temperature and flow values ​​transmitted by the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value, or the natural circulation backwashing duration has reached 24 hours. Then, it controls the first electric gate valve and the second electric gate valve to open, and the two natural circulation backwashing electric gate valves to close, that is, the natural circulation backwashing system is shut down, and normal operation is restored. The system will not control the switching of natural circulation backwashing for 48 hours.

7. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 4, characterized in that, The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a first chemical tank electric gate valve and a second chemical tank electric gate valve. The first chemical tank electric gate valve is located between the first chemical tank and the power backwashing device, and the second chemical tank electric gate valve is located between the second chemical tank and the power backwashing device.

8. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 7, characterized in that, The power backwashing device includes a heating module, a circulating water pump, and a water tank. Depending on the characteristics of the crude oil or the produced water, the electric gate valve of the first or second chemical tank is opened to add the corresponding chemical agent to the water tank. The heating module heats the substances in the water tank, and the circulating water pump pumps the heated chemical mixture or clean water into the plate heat exchanger for soaking and backwashing. The heating module can be powered by diesel, an electric motor, or electricity.

9. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 8, characterized in that, The controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.10 MPa. Based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has decreased to below 70% of the normal average value. Then, the power circulation backwashing process is started.

10. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 9, characterized in that, When the power circulation backwashing process is started, the electric gate valve of the first chemical tank or the electric gate valve of the second chemical tank is opened according to the medium type of the plate heat exchanger, and the corresponding chemical agent is added to the water tank. After a certain period of time, the electric gate valve of the first chemical tank or the electric gate valve of the second chemical tank is closed. After the first or second medicine tank electric gate valve is closed, the power backwashing device is activated, the first and second backwashing valves are opened, and the first and second electric gate valves are closed. The medicine mixture enters the plate heat exchanger through the first backwashing valve and returns to the water tank through the second backwashing valve, performing power circulation backwashing on the plate heat exchanger.

11. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 10, characterized in that, The controller calculates and detects that the pressure difference transmitted by the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa. Based on the temperature and flow values ​​transmitted by the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter, and the ultrasonic flow meter, it calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value, or that the power backflushing duration has reached a predetermined value. Then, the first electric gate valve and the second electric gate valve open, and the first backflushing valve and the second backflushing valve close; the power backflushing device stops and returns to normal operation.

12. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 11, characterized in that, The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a water tank drain valve connected to the drain line of the power backwashing device and a water tank water supply valve connected to the water supply line of the power backwashing device. After the power backwashing device stops, the water tank drain valve is opened and closed when the water level in the tank drops to 0 cm. The water tank water supply valve is opened and closed when the water level in the water tank reaches 100 cm. The system will not control the switching of power circulation backwashing for a predetermined time.

13. The automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 2, characterized in that, The automatic backwashing system for skid-mounted plate heat exchangers based on oil and gas scenarios also includes a check valve connected between the power backwashing device and the first backwashing valve to prevent the medium, i.e., oil or produced water, from flowing into the power backwashing device.

14. An automatic backflushing method for skid-mounted plate heat exchangers in oil and gas scenarios, characterized in that, The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios adopts the automatic backflushing system for skid-mounted plate heat exchangers based on oil and gas scenarios described in claim 1, including: Step 1: When the controller detects that the pressure difference between the first and second pressure transmitters is greater than 0.05 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has dropped to below 85% of the normal average value based on the temperature and flow values ​​transmitted by the first, second, third, and fourth temperature transmitters and the ultrasonic flow meter, natural circulation backwashing is performed. Step 2: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, or the natural circulation backwashing duration has reached 24 hours, then the natural circulation backwashing process is closed. Step 3: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter is greater than 0.10 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has decreased to less than 70% of the normal average value based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, the power circulation backwashing process is started. Step 4: When the controller calculates and detects that the pressure difference transmitted from the first pressure transmitter and the second pressure transmitter has recovered to below 0.02 MPa, and calculates that the heat transfer coefficient of the plate heat exchanger has recovered to more than 95% of the normal average value based on the temperature and flow values ​​transmitted from the first temperature transmitter, the second temperature transmitter, the third temperature transmitter, the fourth temperature transmitter and the ultrasonic flow meter, or when the power backwashing duration reaches a predetermined value, the power circulation backwashing process stops and normal operation is restored.

15. The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 14, characterized in that, In step 1, two electric gate valves for natural circulation backwashing are opened, and the first and second electric gate valves are closed, so that the inlet becomes the outlet and the outlet becomes the inlet, and natural circulation backwashing is performed.

16. The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 14, characterized in that, In step 2, the first and second electric gate valves are opened, and the two natural circulation backwash electric gate valves are closed, that is, the natural circulation backwash is turned off, the normal operation is restored, and the natural circulation backwash switching is no longer controlled within 48 hours.

17. The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 14, characterized in that, In step 3, when the power circulation backwashing process is started, the first or second chemical tank electric gate valve is opened according to the medium type of the plate heat exchanger, and the corresponding chemical agent is added to the water tank. After a certain period of time, the first or second chemical tank electric gate valve is closed. After the first or second medicine tank electric gate valve is closed, the power backwashing device is activated, the first and second backwashing valves are opened, and the first and second electric gate valves are closed. The medicine mixture enters the plate heat exchanger through the first backwashing valve and returns to the water tank through the second backwashing valve, performing power circulation backwashing on the plate heat exchanger.

18. The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 14, characterized in that, In step 4, the first and second electric gate valves are opened, and the first and second backwash valves are closed; the power backwashing device stops and returns to normal operation.

19. The automatic backflushing method for skid-mounted plate heat exchangers based on oil and gas scenarios according to claim 18, characterized in that, In step 4, after the power backwashing device stops, the water tank drain valve is opened, and closed when the water level in the tank drops to 0 cm. The water tank water supply valve is opened, and closed when the water level gauge in the tank reaches 100 cm. The power circulation backwashing switch is no longer controlled within a predetermined time.

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