Electromagnetic heater and method of descaling
By introducing permanent magnets and electromagnetic coils into the electromagnetic heater to change the type of scaling, and combining this with automated cleaning methods, the scaling problem of electromagnetic heaters was solved, improving thermal efficiency and maintenance efficiency, and reducing energy consumption and maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 克拉玛依红山油田有限责任公司
- Filing Date
- 2026-06-30
- Publication Date
- 2026-07-31
AI Technical Summary
Existing electromagnetic heaters are prone to scaling during the heating of water-containing crude oil, which leads to decreased thermal efficiency and increased maintenance costs. Existing descaling methods are difficult to operate or have low automation, and there is a lack of efficient and suitable cleaning solutions.
An electromagnetic heater structure was designed, including a heating and descaling shell and a slag discharge shell. A permanent magnet assembly and an electromagnetic coil assembly were used to change the type of scale. Hard scale was turned into soft scale by magnetic field interference. The structure was combined with a differential pressure transmitter and cleaning equipment for automated cleaning. Magnetic field and chemical methods were used to remove scale in a coordinated manner.
It effectively reduces the amount of scale buildup on electromagnetic heaters, reduces cleaning frequency, lowers heat loss and system energy consumption, simplifies maintenance procedures, and extends equipment uptime.
Smart Images
Figure CN122486261A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of descaling technology, specifically to an electromagnetic heater and a descaling method. Background Technology
[0002] Electromagnetic heaters are widely used in oil fields for heating crude oil. Typically, to achieve optimal heating performance, the internal heating surface of an electromagnetic heater is designed in a spiral shape, resulting in a rapid heating rate and a long residence time for the heating medium. However, during the heating of water-containing crude oil, electromagnetic heaters are prone to scaling in the internal tube bundles due to various factors such as internal structure and materials. This can affect thermal efficiency and increase maintenance costs.
[0003] Currently, common descaling methods include: high-pressure water jet descaling, mechanical scraping and brushing descaling, ultrasonic descaling, and chemical descaling. Physical descaling methods require disassembling the electromagnetic heater, which is difficult to operate, and repeated disassembly affects the lifespan of the electromagnetic heater. Moreover, the scale on electromagnetic heaters is mostly hard scale, which is not effective with physical descaling methods. Chemical descaling methods often use cleaning equipment to remove scale, but existing cleaning equipment has a low degree of automation and takes a long time to prepare (installation, pressure testing, etc.), resulting in poor anti-scaling effect at the front end of the electromagnetic heater. Furthermore, there is a lack of efficient descaling methods that can be adapted to multiple electromagnetic heaters.
[0004] Chinese patent document CN210772735U discloses an electromagnetic heater, which includes a shell with an inner cavity. The shell has a material inlet and a material outlet at its two ends. The inner cavity of the shell contains multiple tube bundles. The input end of each tube bundle is connected to the material inlet, and the output end of each tube bundle is connected to the material outlet. Magnetic conductors are filled between the inner wall of the shell and the tube bundles, and between each tube bundle. A magnetic induction electromagnetic coil is spirally wound on the outer surface of the shell. The shell, tube bundles, and magnetic conductors are all made of magnetically conductive material. This electromagnetic heater places the electromagnetic coil on the outside of the shell, while there are multiple tube bundles inside the shell, resulting in low thermal efficiency and inconvenience for subsequent maintenance.
[0005] Chinese patent document CN208317043U discloses an explosion-proof electromagnetic heater for both oil and gas applications. The cylindrical electromagnetic heater body consists of a cylindrical body with an external flange at one end and a sealed end at the other. An output pipe connector is installed at the external flange end of the cylinder, and a drain pipe connector is installed at the bottom. A transition section is welded to the flange cover of the finned tube. The jacketed electromagnetic heater rod body is an electromagnetic core-type steel tube with an induction winding electromagnetic coil wound around it. An outer sheath of finned steel tube is fitted around the electromagnetic rod core tube. The finned tube transition section is sealed with a flange connecting to an explosion-proof junction box. A heat transfer medium is filled in the closed cavity between the outer sheath of the finned steel tube and the inner core tube of the electromagnetic rod. This electromagnetic heater has a relatively complex structure and is prone to scale buildup, making cleaning and maintenance extremely difficult once scale accumulates internally.
[0006] Because electromagnetic heaters, as core-shell type equipment, operate in harsh environments of high temperature, high pressure, strong corrosion, and high load for extended periods, their internal core components are prone to wear, scaling, corrosion, aging, or malfunction. The external shell may also experience issues such as aging seals and loosening of interfaces due to prolonged pressure. To ensure the safety and reliability of the equipment and avoid production interruptions, safety accidents, or economic losses caused by equipment failure, it is essential to regularly inspect and replace internal components, clean and maintain internal media, and troubleshoot and eliminate potential hazards. However, these operations often require disassembling the core-shell equipment, completing the necessary procedures, and then reassembling it, making the cleaning process cumbersome. Summary of the Invention
[0007] This invention provides an electromagnetic heater and a descaling method, which overcomes the shortcomings of the prior art and can effectively solve the problem of low descaling effect of existing electromagnetic heaters.
[0008] One of the technical solutions of this invention is achieved through the following measures: an electromagnetic heater includes a heating and descaling housing and a slag discharge housing that are detachably and fixedly installed together from left to right. A sealing head is fixedly installed at the right end of the slag discharge housing. A drain pipe is fixedly connected to the right side of the slag discharge housing, and a drain valve is installed on the drain pipe. An inlet pipe is coaxially fitted inside the heating and descaling housing. A sealing plate is fixedly installed between the outer left side of the inlet pipe and the inner side of the heating and descaling housing. A protective shell is fixedly installed on the outer side of the inlet pipe corresponding to the right side of the sealing plate. The outer side of the protective shell is connected to the heating... An annular liquid outlet channel is formed between the inner sides of the descaling shell. A liquid outlet pipe is fixedly connected to the outer left side of the heated descaling shell. The inner wall of the protective shell and the outer wall of the liquid inlet pipe form a closed annular heating chamber. Several heating coils are wound around the outer side of the liquid inlet pipe in the heating chamber. The ends of the heating coils are sealed and pass through the protective shell and the left side of the sealing plate from the inside to the outside. Several spiral fins are distributed at intervals along the circumference on the outer side of the protective shell. An inlet pipeline is detachably and fixedly installed at the left end of the liquid inlet pipe. An electromagnetic descaling component is provided on the outer side of the inlet pipeline to promote the increase of schist crystal form in calcium carbonate precipitation.
[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: As a preferred embodiment, the electromagnetic descaling assembly may include several permanent magnet groups spaced apart along the length of the inlet pipeline. Each permanent magnet group includes several permanent magnets that are sequentially fixed and installed along the circumferential direction on the outside of the inlet pipeline, with adjacent permanent magnets attracting each other.
[0010] The aforementioned permanent magnets can be arc-shaped with the opening facing inward. A rubber pad is provided between the inner side of the permanent magnet and the outer side of the inlet pipeline, and a clamp is provided on the outer side of each permanent magnet assembly.
[0011] As a preferred embodiment, the electromagnetic descaling assembly may include several turns of an electromagnetic coil wound around the outside of the inlet pipeline.
[0012] The above may also include a controller, with a differential pressure transmitter installed between the inlet pipe and the outlet pipe at the position corresponding to the left side of the sealing plate. The differential pressure transmitter, the electromagnetic coil, the heating coil, and the drain valve are all connected to the controller.
[0013] A slag collection trough can be fixedly installed on the lower inner side of the slag discharge shell at the position corresponding to the right of the liquid inlet pipe. A sewage discharge hole connected to the sewage discharge pipeline is provided on the lower side of the slag collection trough. A perforated plate structure guide plate is fixedly installed between the slag collection trough and the slag discharge shell. Several through holes are staggered on the left side of the perforated plate structure guide plate.
[0014] The outside of the inlet pipe at the left position of the aforementioned protective shell can be fixedly connected to a backwash outlet pipe. The other end of the backwash outlet pipe passes through the outside of the heating and descaling shell in a sealed manner. The outside of the left side of the heating and descaling shell is fixedly connected to a backwash inlet pipe that is connected to the outlet channel. Backwash control valves are installed on both the backwash inlet pipe and the backwash outlet pipe. An inlet valve is installed on the inlet pipe at the left position of the sealing plate, and an outlet valve is installed on the outlet pipe.
[0015] The helix angle of the aforementioned fins can be from 3° to 10°.
[0016] The fins mentioned above can be made of stainless steel.
[0017] The upper outer side of the aforementioned heating and descaling housing may be provided with at least two lifting rings spaced apart on the left and right, and the lower outer side of the heating and descaling housing may be provided with at least two supports spaced apart on the left and right.
[0018] The second technical solution of the present invention is achieved through the following measures: a descaling method, comprising the following steps: The first step is to collect the pressure difference between the inlet and outlet pipes. When the pressure difference is greater than the set value, the cleaning operation will begin. The second step is to close the inlet valve, outlet valve, electromagnetic coil, and heating coil. Third, open the drain valve to drain the electromagnetic heater and then close the drain valve. The fourth step is to connect the backwash inlet line to the cleaning equipment supply line and the backwash outlet line to the cleaning equipment return line. Fifth step: Open the backwash control valve, and the cleaning fluid of the cleaning equipment circulates between the electromagnetic heater and the cleaning equipment; Step 6: If the pressure difference is less than the set value within the set cleaning time, the rinsing operation is successful and rinsing stops; if the pressure difference is greater than or equal to the set value within the set cleaning time, the rinsing operation fails and proceeds to step 7. Step 7: After adding the cleaning agent into the cleaning equipment, perform acid washing on the electromagnetic heater; Step 8: If the differential pressure is less than the set value within the set cleaning time, the pickling operation is successful and the pickling is stopped; if the differential pressure is greater than or equal to the set value within the set cleaning time, the pickling operation fails and the cleaning operation is stopped.
[0019] The following are further optimizations and / or improvements to the second technical solution of the above invention: The cleaning equipment in the fourth step mentioned above may include a skid, a chemical storage tank, a reaction tank, a waste liquid tank, and a circulating pump. The chemical storage tank, the reaction tank, and the waste liquid tank are fixedly installed on the upper side of the skid from left to right. The circulating pump is fixedly installed on the upper right side of the skid corresponding to the position behind the waste liquid tank. A return liquid pipeline is fixedly connected to the upper rear side of the reaction tank. A connecting pipeline is fixedly connected between the lower right side of the reaction tank and the inlet of the circulating pump. A supply liquid pipeline is fixedly connected to the outlet of the circulating pump. A dosing pipeline is fixedly connected between the chemical storage tank and the reaction tank, and a dosing valve is installed on the dosing pipeline. A waste liquid pipeline is fixedly connected between the reaction tank and the lower part of the waste liquid tank, and a drain valve is installed on the waste liquid pipeline. An overflow pipeline is fixedly connected between the upper part of the reaction tank and the waste liquid tank.
[0020] In the fourth step mentioned above, the supply liquid line and the backwash inlet liquid line, as well as the backwash outlet liquid line and the return liquid line of the cleaning equipment, are all connected by flexible hoses.
[0021] In step six above, if the pressure difference is less than 0.05 MPa within 20 minutes, the flushing operation is successful and the flushing is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the flushing operation fails and proceeds to step seven.
[0022] In step 8 above, if the pressure difference is less than 0.05 MPa within 20 minutes, the pickling operation is successful and pickling is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the pickling operation fails and the cleaning operation is stopped.
[0023] In step seven above, during the acid washing process, the pH value in the reaction tank is 2-3.
[0024] This invention features a reasonable and compact structure. Water-containing crude oil enters through the inlet pipeline. A magnetic field is added outside the inlet pipeline, altering the scale type through electromagnetic interference. The scale in the liquid changes from hard scale to soft scale that is less prone to adhesion, improving the scale inhibition effect on the water-containing crude oil. The soft scale is easily flushed away and does not adhere easily. After flowing out of the inlet pipe, the soft scale slows down and settles, allowing it to be periodically discharged through a drain valve, reducing the amount of scale buildup in the equipment. The remaining liquid enters an annular outlet channel, where it is heated to 50°C by fins and a heating coil before finally flowing out through the outlet pipe. This centralized descaling reduces the frequency of electromagnetic heater cleaning, minimizes heat loss, and lowers system energy consumption. Attached Figure Description
[0025] Appendix Figure 1 These are schematic diagrams of the main cross-sectional structure of embodiments one to three of the present invention.
[0026] Appendix Figure 2 This is a schematic diagram of the left-side cross-sectional structure of the inlet pipeline in Embodiments 1 to 3 of the present invention.
[0027] Appendix Figure 3 This is a schematic diagram of the front sectional view of Embodiment 4 of the present invention.
[0028] Appendix Figure 4 This is a three-dimensional structural diagram of the fins in Embodiments 1 to 10 of the present invention.
[0029] Appendix Figure 5 This is a schematic diagram of the left-side structure of the guide plate in embodiments six to ten of the present invention.
[0030] Appendix Figure 6 This is a top view of the cleaning equipment in embodiments 11 to 16 of the present invention.
[0031] The codes in the attached diagram are as follows: 1 is the heating and descaling shell, 2 is the slag discharge shell, 3 is the end cap, 4 is the drain pipe, 5 is the drain valve, 6 is the liquid inlet pipe, 7 is the sealing plate, 8 is the protective shell, 9 is the liquid outlet channel, 10 is the liquid outlet pipe, 11 is the heating chamber, 12 is the permanent magnet, 13 is the electromagnetic coil, 14 is the fin, 15 is the inlet pipe, 16 is the heating coil, 17 is the rubber gasket, 18 is the clamp, 19 is the slag collection tank, 20 is the guide plate, 21 is the through hole, 22 is the... 23 is the lifting ring, 24 is the support, 25 is the backwash outlet line, 26 is the backwash inlet line, 27 is the inlet valve, 28 is the outlet valve, 29 is the skid, 30 is the drug storage tank, 31 is the reaction tank, 32 is the waste liquid tank, 33 is the circulation pump, 34 is the return line, 35 is the connecting line, 36 is the supply line, 37 is the dosing line, 38 is the dosing valve, 39 is the waste liquid line, 40 is the drain valve, and 41 is the overflow line. Detailed Implementation
[0032] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.
[0033] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.
[0034] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figure 1As shown, the electromagnetic heater includes a heating and descaling housing 1 and a slag discharge housing 2, which are detachably and fixedly installed together from left to right. A sealing head 3 is fixedly installed on the right end of the slag discharge housing 2. A drain pipe 4 is fixedly connected to the right side of the slag discharge housing 2, and a drain valve 5 is installed on the drain pipe 4. An inlet pipe 6 is coaxially fitted inside the heating and descaling housing 1. A sealing plate 7 is fixedly installed between the outer left side of the inlet pipe 6 and the inner side of the heating and descaling housing 1. A protective shell 8 is fixedly installed on the outer side of the inlet pipe 6 corresponding to the right side of the sealing plate 7. An annular outlet is formed between the outer side of the protective shell 8 and the inner side of the heating and descaling housing 1. Liquid channel 9, the outer left side of the heating and descaling housing 1 is fixedly connected to the liquid outlet pipe 10, the inner wall of the protective housing 8 and the outer wall of the liquid inlet pipe 6 form a closed annular heating chamber 11, the heating chamber 11 is provided with several heating coils 16 wound around the outer side of the liquid inlet pipe 6, the ends of the heating coils 16 pass through the protective housing 8 and the left side of the sealing plate 7 in sequence from the inside to the outside, and several spiral fins 14 are distributed circumferentially on the outer side of the protective housing 8. The left end of the liquid inlet pipe 6 is detachably and fixedly installed with an inlet pipeline 15, and the outer side of the inlet pipeline 15 is provided with an electromagnetic descaling component to promote the increase of schist crystal form in calcium carbonate precipitation.
[0035] The electromagnetic descaling component can generate a magnetic field within the inlet pipeline 15. After the magnetic field is applied, the crystal structure of each material surface changes. Influenced by the Lorentz force in the magnetic field, the distribution of ions entering the nucleation sites is altered, resulting in different growth rates of calcium carbonate in the water-bearing crude oil at the high-barrier growth points on the nucleus surface. This promotes the transformation of previously formed colloidal amorphous calcium carbonate particles into aragonite crystals. The Lorentz force affects the interaction between calcium carbonate particles and the Ca in the water-bearing crude oil. 2+ and CO3 2- The exchange between free ions leads to changes in the surface composition of calcium carbonate particles, promoting an increase in the schist crystal form of calcium carbonate precipitation, i.e., forming soft scale / loose scale, which is easier to be discharged with water flow. Electromagnetic descaling components can interfere with the scale form, forming soft scale / loose scale to achieve easy cleaning.
[0036] The outer side of the protective shell 8 has six spiral fins 14 arranged at circumferential intervals. The pitch of the fins 14 is 200 mm. The liquid inlet of a single electromagnetic heater is 5 m³. 3The inlet pipeline is DN150 with a flow rate of 0.08 m / s. The residence time of scale-forming ions in the magnetic field within the inlet pipeline 15 is greater than or equal to 2.0 s. Thus, the shortest magnetization distance is 2 * 0.08 = 0.16 m. Considering factors such as magnetic field attenuation, the magnetization distance needs to be designed to be 1 m. The magnetic induction intensity at the center of the pipeline needs to be greater than or equal to 800 Gs to achieve a stable scale inhibition effect. The magnetic induction intensity needs to be greater than 900 Gs after penetrating 20# steel. There is a gap between the rightmost permanent magnet group and the left end of the inlet pipe 6 to avoid interference from the inlet vortex. The electromagnetic descaling component is installed on the outside of the inlet pipeline 15 between 0.3 m and 1.3 m from the inlet (left end of the inlet pipe 6). The protective shell 8 is made of 20# steel, and the inlet pipe 6 is made of 345D material.
[0037] After the water-containing crude oil passes through the inlet pipe 15 in the electromagnetic descaling component, the scale in the incoming liquid changes from hard scale to soft scale that is not easy to adhere to. After the soft scale flows out of the inlet pipe 6, the speed decreases and it settles down. The remaining liquid enters the annular outlet channel 9, is heated to 50°C by the action of the fins 14 and the electromagnetic coil 13, and finally flows out through the outlet pipe 10.
[0038] Inlet pipeline 15 introduces water-containing crude oil (water content below 30%, temperature 25℃). A magnetic field is added outside inlet pipeline 15 to change the scale type through electromagnetic interference, transforming the scale in the liquid from hard scale to soft scale that is not easy to adhere to. This improves the scale inhibition effect of the water-containing crude oil. The soft scale is easy to flush away and does not adhere easily. After the soft scale flows out of inlet pipe 6, its velocity decreases and it settles down. It can be discharged periodically through drain valve 5, reducing the amount of scale on the equipment. The remaining liquid enters the annular outlet channel 9, is heated to 50℃ by the action of fins 14 and heating coil 16, and finally flows out through outlet pipe 10. This centralized descaling reduces the frequency of scale removal by the electromagnetic heater, reduces heat loss, and lowers system energy consumption.
[0039] The above-mentioned electromagnetic heater can be further optimized and / or improved according to actual needs: Example 2: As an optimization of Example 1, as shown in the appendix Figure 1 , 2 As shown, the electromagnetic descaling assembly includes several permanent magnet groups spaced apart along the length of the inlet pipeline 15. Each permanent magnet group includes several permanent magnets 12 that are fixedly installed along the circumferential direction on the outside of the inlet pipeline 15. Adjacent permanent magnets 12 attract each other.
[0040] The permanent magnet 12 is made of high-temperature resistant neodymium iron boron permanent magnet material, grade 35SH / 40SH. During use, it can avoid demagnetization. The permanent magnet group is arranged in 200mm intervals, synchronized with the fluid swirl pitch (fin pitch 14), so that each swirling flow passes through the strong magnetic field area, thus maximizing scale inhibition efficiency. Each group has 4 permanent magnets 12, with the N / S poles of the permanent magnets 12 arranged alternately and evenly to form a closed ring magnetic field. The permanent magnets 12 are externally applied to the inlet pipeline 15, which can interfere with the scale type, forming soft / loose scale for easy cleaning.
[0041] Example 3: As an optimization of the above examples, as shown in the appendix. Figure 1 , 2 As shown, the permanent magnet 12 is an arc shape with the opening facing inward. A rubber pad 17 is provided between the inner side of the permanent magnet 12 and the outer side of the inlet pipeline 15. A clamp 18 is provided on the outer side of each permanent magnet group.
[0042] The magnetic induction intensity of permanent magnet 12 is greater than 900 Gauss. Permanent magnet 12 is an arc shape with an inward opening. The arc of permanent magnet 12 fits the outer wall of inlet pipeline 15, achieving full coverage and high fit for external installation. Four sets of permanent magnets are installed in the range of 300mm to 1300mm from the equipment inlet (left end of liquid inlet pipe 6). A set of circular permanent magnets is installed every 200mm. Thus, 1000 / 200=5 sets of permanent magnets are needed, that is, 5*4=20 permanent magnets 12. Each set of 4 arc-shaped permanent magnets interlock and wrap around inlet pipeline 15 with alternating polarities (NSNS). The same poles must not be adjacent to each other to ensure uniform magnetic field penetration. Each set of permanent magnets is fastened with two 316L stainless steel clamps 18. A 2mm high-temperature resistant silicone pad 17 is used between the inner side of permanent magnet 12 and the outer side of inlet pipeline 15 to prevent the permanent magnet 12 from loosening, wearing, and electrochemical corrosion.
[0043] Example 4: As another optimization of Example 1, as shown in the appendix Figure 3 As shown, the difference between this embodiment and Embodiment 2 lies entirely in the electromagnetic descaling component, which includes several turns of electromagnetic coil 13 wound around the outside of the inlet pipeline 15.
[0044] The electromagnetic descaling component includes an electromagnetic coil 13 with several turns spirally wound around the outside of the inlet pipe 15. The electromagnetic coil 13 has 100 turns, and the heating coil 16 has a frequency of 50kHz-100kHz. To avoid mutual interference, the frequency of the electromagnetic coil 13 is less than or equal to 0.3 times the frequency of the heating coil 16. At 15kHz, the fluid is subjected to 18,900 alternating magnetizations, which is greater than the minimum requirement of 2,000 times. This can fully polarize ions and destroy crystal nucleation, achieving stable and efficient scale inhibition. To prevent wear of the electromagnetic coil 13, a layer of alkali-free glass fiber tape is wound around the outside of the inlet pipe 15. The alkali-free glass fiber tape is wound in one direction (counterclockwise or clockwise), evenly distributed along the axial direction, with uniform winding force, without loosening or stacking. The electromagnetic coil 13 is powered by an independent power supply from a nearby explosion-proof maintenance box.
[0045] Example 5: As an optimization of the above example, it also includes a controller. A differential pressure transmitter is provided between the inlet pipe 6 and the outlet pipe 10 on the left side of the sealing plate 7. The differential pressure transmitter, the electromagnetic coil 13, the heating coil 16 and the drain valve 5 are all connected to the controller.
[0046] A differential pressure transmitter is installed between the outlet pipe 10 and the inlet pipe 6 located to the left of the corresponding fixed plate 16. The heating coil 16 is independently powered by an explosion-proof maintenance box located nearby on site. The controller is installed on the bracket and connected to the heating coil 16 through an oil-resistant shielded cable. The cable is laid separately from the power cable of the heating coil 16. The differential pressure transmitter is a known technology and is convenient for detecting the operating condition of the electromagnetic heater. The controller is a known technology, such as a programmable controller. The differential pressure transmitter can accurately determine the operating condition of the electromagnetic heater and can descale according to the on-site production conditions, saving manpower and improving descaling efficiency.
[0047] The drain valve 5 is an electric valve. The drain operation time is set by the controller, so that the drain valve 5 opens periodically. This allows the function of draining sewage according to the predetermined drain operation time. In this embodiment, the drain operation time (drainage cycle) is 30 days, so sewage is drained once a month. The sewage discharge time is 2 seconds. After the sewage discharge time is over, the drain valve 5 closes.
[0048] Example 6: As an optimization of the above examples, as shown in the appendix Figure 1 , 3 As shown in Figure 5, a slag collection trough 19 is fixedly installed on the lower inner side of the slag discharge shell 2 corresponding to the position to the right of the liquid inlet pipe 6. A sewage discharge hole connected to the sewage discharge pipeline 4 is provided on the lower side of the slag collection trough 19. A perforated plate structure guide plate 20 is fixedly installed between the slag collection trough 19 and the slag discharge shell 2. Several through holes 21 are staggered on the left side of the perforated plate structure guide plate 20.
[0049] The guide plate 20 reduces the flow rate of fluid entering the annular outlet channel 9 from the inlet pipe 6, facilitating the sedimentation of soft scale. Mud and scale enter the slag discharge shell 2 and settle into the slag collection tank 19 after passing through the perforated plate guide plate 20. It is periodically discharged through the sewage pipe 4. The perforated plate guide plate 20 has a diameter of 263 mm, a hole diameter of 8 mm, and a mesh count of 432. Several through holes 21 (triangularly distributed) are staggered on the left side of the perforated plate guide plate 20. The slag collection tank 19 is arranged below the perforated plate guide plate 20. The slag collection tank 19 has dimensions of 200×60×20 mm and a downward-recessed confluence channel with a slope of 10°. Mud and scale are discharged through the sewage pipe 4 and the sewage valve 5.
[0050] In this application, the scale in the liquid will be changed from hard scale to soft scale that is not easy to adhere to. After the soft scale flows out of the liquid inlet pipe 6, its speed decreases and it settles in the slag collection tank 19, so that it can be discharged periodically through the drain valve 5.
[0051] Example 7: As an optimization of the above examples, as shown in the appendix. Figure 1 , 3 As shown, a backwash outlet pipeline 24 is fixedly connected to the outside of the inlet pipe 6 corresponding to the left position of the protective shell 8. The other end of the backwash outlet pipeline 24 passes through the outside of the heating descaling shell 1 in a sealed manner. A backwash inlet pipeline 25 connected to the outlet channel 9 is fixedly connected to the outside of the left part of the heating descaling shell 1. Backwash control valves 26 are installed on both the backwash inlet pipeline 25 and the backwash outlet pipeline 24. An inlet valve 27 is installed on the inlet pipeline 15 corresponding to the left position of the sealing plate 7, and an outlet valve 28 is installed on the outlet pipe 10.
[0052] The inlet valve 27 is installed on the inlet pipe 15 on the left side of the electromagnetic descaling assembly. To ensure normal backwashing even after the interface pipe 15 is removed, a regulating valve is also installed on the inlet pipe 6 between the inlet pipe 15 and the heating descaling housing 1. This arrangement allows for periodic or on-demand cleaning of the inlet pipe 6, fins 14, and heating descaling housing 1, reducing cleaning difficulty and facilitating the maintenance of the electromagnetic heater.
[0053] Example 8: As an optimization of the above examples, as shown in the appendix Figure 1 , 3 As shown in Figure 4, the helix angle of fin 14 is 3° to 10°.
[0054] When the helix angle of fin 14 is between 3° and 10°, the tilt angle of fin 14 is smaller, and the fluid flows along a smaller helix. This continuously disturbs the boundary layer of the fluid, increasing the wall shear force and making it less likely for scale to deposit on the surface of fin 14. When the helix angle is greater than 10°, the fluid swirling phenomenon is too strong, with local backflow zones and low-speed zones, making it easy for scale and oil to accumulate on the surface of fin 14. When the helix angle is less than 3°, there is almost no wall shear effect. In this embodiment, the helix angle of fin 14 can be 7°. Such fin 14 has the advantages of gentle swirling, no dead zones, and continuous disturbance of the boundary layer. Both the leading edge and the tail of fin 14 are provided with rounded chamfers with a radius of 1.0mm-1.5mm. This makes the flow field on the surface of fin 14 smoother, so that there are no eddies or stagnation phenomena when the fluid flows through it, increasing the difficulty of scale formation on the surface of fin 14.
[0055] Example 9: As an optimization of the above examples, as shown in the appendix Figure 1 , 3 As shown in Figure 4, fin 14 is made of stainless steel.
[0056] Fin 14 is made of stainless steel to improve the anti-fouling effect. 316L stainless steel is preferred, but 235B material can also be used for fin 14.
[0057] Example 10: As an optimization of the above embodiments, as shown in the appendix Figure 1 , 3 As shown, at least two lifting rings 22 are provided on the upper outer side of the heating and descaling housing 1 at intervals on the left and right, and at least two supports 23 are provided on the lower outer side of the heating and descaling housing 1 at intervals on the left and right.
[0058] During use, the lifting ring 22 makes it easy to lift the heating and descaling housing 1 and pull out the liquid inlet pipe 6 and fins 14, which is convenient for maintenance. The support 23 can support the heating and descaling housing 1 and prevent the heating and descaling housing 1 from deforming due to excessive load during operation.
[0059] Example 11: As attached Figure 1 , 3 As shown in Figure 6, the cleaning method includes the following steps: The first step is to collect the pressure difference between the inlet pipe 6 and the outlet pipe 10. When the pressure difference is greater than the set value, the cleaning operation will begin. The second step is to close the inlet valve 27, the outlet valve 28, the electromagnetic coil 13, and the heating coil 16. Third step, open drain valve 5 to drain the electromagnetic heater, and close drain valve 5 after draining. The fourth step is to connect the backwash inlet line 25 to the liquid supply line 36 of the cleaning equipment, and connect the backwash outlet line 24 to the return line 34 of the cleaning equipment. Fifth step, open backwash control valve 26, and the cleaning fluid of the cleaning equipment circulates between the electromagnetic heater and the cleaning equipment; Step 6: If the pressure difference is less than the set value within the set cleaning time, the rinsing operation is successful and rinsing stops; if the pressure difference is greater than or equal to the set value within the set cleaning time, the rinsing operation fails and proceeds to step 7. Step 7: After adding the cleaning agent into the cleaning equipment, perform acid washing on the electromagnetic heater; Step 8: If the differential pressure is less than the set value within the set cleaning time, the pickling operation is successful and the pickling is stopped; if the differential pressure is greater than or equal to the set value within the set cleaning time, the pickling operation fails and the cleaning operation is stopped.
[0060] Electromagnetic heater cleaning method and judgment criteria: When the data collected by the differential pressure transmitter is greater than the set value, the pressure difference between the inlet and outlet of the electromagnetic heater is large. At this time, the electromagnetic heater is severely scaled or blocked, requiring cleaning. The electromagnetic heater is manually shut down, and then the liquid inside the electromagnetic heater is drained before starting the cleaning and descaling operation. In this embodiment, when the data collected by the differential pressure transmitter is greater than 0.1 MPa, that is, when the pressure difference between the inlet pipe 6 and the outlet pipe 10 is greater than 0.1 MPa, the alarm module connected to the controller issues an audible and visual alarm, and the cleaning and descaling operation begins.
[0061] The cleaning equipment is connected to the backwash inlet line 25 and backwash outlet line 24 of the electromagnetic heater via a flexible hose. The flexible hose is connected to the backwash inlet line 25 and backwash outlet line 24 of the electromagnetic heater via flanges, forming a circulating cleaning pipeline. If the differential pressure is greater than or equal to the set value within the set cleaning time, the acid washing operation fails, and the cleaning operation is stopped. Other descaling methods are required. This descaling method for the electromagnetic heater is easy to operate, simplifies the maintenance process, shortens maintenance time, and thus extends the normal operating time of the electromagnetic heater.
[0062] The above-mentioned cleaning methods can be further optimized and / or improved according to actual needs: Example 12: As an optimization of the above embodiments, as shown in the appendix Figure 6As shown, the cleaning equipment in the fourth step includes a skid 29, a chemical storage tank 30, a reaction tank 31, a waste liquid tank 32, and a circulating pump 33. The chemical storage tank 30, reaction tank 31, and waste liquid tank 32 are fixedly installed on the upper side of the skid 29 from left to right. The circulating pump 33 is fixedly installed on the upper right side of the skid 29, corresponding to the position behind the waste liquid tank 32. A return liquid pipeline 34 is fixedly connected to the upper rear side of the reaction tank 31. The lower right side of the reaction tank 31 is connected to the inlet of the circulating pump 33. A connecting pipeline 35 is fixedly connected between the outlets; a liquid supply pipeline 36 is fixedly connected to the outlet of the circulating pump 33; a dosing pipeline 37 is fixedly connected between the drug storage tank 30 and the reaction tank 31; a dosing valve 38 is installed on the dosing pipeline 37; a waste liquid pipeline 39 is fixedly connected between the reaction tank 31 and the lower part of the waste liquid tank 32; a drain valve 40 is installed on the waste liquid pipeline 39; and an overflow pipeline 41 is fixedly connected between the upper part of the reaction tank 31 and the waste liquid tank 32.
[0063] The storage tank 30, reaction tank 31, and waste liquid tank 32 can be arranged alternately or fixed together in sequence. The reaction tank 31 is a polytetrafluoroethylene (PTFE) lined water tank, which has the advantages of strong chemical inertness and resistance to cleaning fluid corrosion. It is suitable for operating temperatures of 0-100℃ and pressures of 0-1MPa. The reaction tank 31 is connected to the pipeline via flanges. Both the reaction tank 31 and the storage tank 30 are equipped with level gauges. The dosing valve 38 is an electric valve. The dosing valve 38 and the circulation pump 33 are both connected to the cleaning controller. The cleaning controller is a programmable controller that automatically opens and closes the dosing valve 38 to add liquid from the storage tank 30 to the reaction tank 31. The material of the circulation pump 33 is selected according to the cleaning fluid. Considering the scaling and pressure buildup of the electromagnetic heater, the rated pressure of the circulation pump 33 is 1.2-1.5 times the working pressure. A circulation pump 33 with a pressure of 1.2MPa is selected. The circulation pump 33 adopts frequency conversion control and the circulation flow rate can be set.
[0064] During the rinsing operation, cleaning fluid needs to be added to the reaction tank 31 in advance, and the flow rate and rinsing time of the circulating pump 33 should be set. When the pressure difference between the inlet and outlet of the electromagnetic heater drops to the set value within the rinsing time, the rinsing should be stopped and the original process resumed. If the pressure difference is greater than or equal to the set value within the set rinsing time, the rinsing operation fails and acid washing is required. The dosing valve 38 is opened to control the pH value in the reaction tank 31 within the set concentration range. If the pressure difference is less than the set value within the set rinsing time, the acid washing operation is successful, and the acid washing is stopped and the original process resumed. If the pressure difference is greater than or equal to the set value within the set rinsing time, the acid washing operation fails, the rinsing operation is stopped, and other methods for descaling are required.
[0065] Example 13: As an optimization of the above embodiments, as shown in the appendix Figure 1 , 3As shown in Figure 6, in the fourth step, the liquid supply line 36 and the backwash inlet line 25, and the backwash outlet line 24 and the return line 34 of the cleaning equipment are all connected by flexible hoses.
[0066] To avoid acid corrosion and improve temperature resistance, the hose can be made of metal or non-metal composite pipe, such as DN50 rubber-lined hose or non-metal composite pipe. The hose is connected to the backwash inlet line 25 and backwash outlet line 24 of the electromagnetic heater through flanges.
[0067] Example 14: As an optimization of the above embodiments, as shown in the appendix. Figure 1 , 3 As shown in Figure 6, in step 6, if the pressure difference is less than 0.05 MPa within 20 minutes, the flushing operation is successful and the flushing is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the flushing operation fails and proceeds to step 7.
[0068] Add rinsing solution to reaction tank 31, set the flow rate of circulation pump 33 and the cleaning time to 20 minutes, start circulation pump 33 to backwash the electromagnetic heater. Stop rinsing and resume the original process when the pressure difference between the inlet and outlet of the electromagnetic heater drops to 0.05 MPa within 20 minutes; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the rinsing operation fails and acid washing is required.
[0069] Example 15: As an optimization of the above embodiments, as shown in the appendix. Figure 1 , 3 As shown in Figure 6, in step 8, if the pressure difference is less than 0.05 MPa within 20 minutes, the pickling operation is successful and pickling is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the pickling operation fails and the cleaning operation is stopped.
[0070] The reaction tank 31 is equipped with an online pH meter connected to the cleaning controller, which can detect the pH value of the liquid inside the reaction tank 31 online. Clean water is added to the chemical storage tank 30, and the upper and lower limits of the pH value are set. The change of the pH value monitored by the online pH meter within 10 minutes should not exceed 0.1. If the pressure difference is less than 0.05 MPa within 20 minutes, the acid washing operation is successful, the acid washing is stopped, and the original process is resumed. If the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the acid washing operation fails, the cleaning operation is stopped, and other methods of descaling need to be adopted.
[0071] Example 16: As an optimization of the above embodiments, as shown in the appendix Figure 6 As shown, in step seven, during the acid washing process, the pH value inside reaction tank 31 is 2-3.
[0072] When acid washing is required, the dosing valve 38 is opened, and the pH online detector monitors the pH value of the liquid inside the reaction tank 31. When the pH value in the reaction tank 31 reaches the set concentration (2-3), the dosing valve 38 is closed. This controls the pH value in the reaction tank 31 within the set concentration range. When the pH online detector detects a pH value greater than 3, the dosing valve 38 is opened, and the cleaning solution is added to the reaction tank 31, and the pH value begins to decrease. When the pH online detector detects a pH value of 2, the dosing valve 38 is closed. To ensure thorough cleaning, the pressure difference must be less than 0.05 MPa within 20 minutes, and the pH value monitored by the online detector must not change by more than 0.1 within 10 minutes. Once these conditions are met, the circulation pump 33 stops, and the acid washing operation ends. If these conditions are not met, acid washing continues.
[0073] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
Claims
1. An electromagnetic heater characterised in that The device comprises a heating and descaling housing and a slag discharge housing, which are detachably and fixedly installed together from left to right. A cap is fixedly installed at the right end of the slag discharge housing, and a drain pipe is fixedly connected to the right side of the slag discharge housing. A drain valve is installed on the drain pipe. An inlet pipe is coaxially fitted inside the heating and descaling housing. A sealing plate is fixedly installed between the outer left side of the inlet pipe and the inner side of the heating and descaling housing. A protective shell is fixedly installed on the outer side of the inlet pipe corresponding to the right side of the sealing plate. An annular outlet channel is formed between the outer side of the protective shell and the inner side of the heating and descaling housing. An outlet pipe is fixedly connected to the outer left side of the heating and descaling housing. The inner wall of the protective shell and the outer wall of the inlet pipe form a closed annular heating chamber. Several heating coils are wound around the outer side of the inlet pipe inside the heating chamber. The ends of the heating coils are sealed and pass through the left side of the protective shell and the sealing plate from the inside to the outside. Several spiral fins are distributed circumferentially on the outer side of the protective shell. An inlet pipe is detachably and fixedly installed at the left end of the inlet pipe. An electromagnetic descaling component is provided on the outer side of the inlet pipe to promote the increase of schist crystals in calcium carbonate precipitation.
2. The electromagnetic heater of claim 1, wherein The electromagnetic descaling assembly includes several permanent magnet groups spaced apart along the length of the inlet pipeline. Each permanent magnet group includes several permanent magnets that are sequentially fixed and installed along the circumference of the inlet pipeline. Adjacent permanent magnets attract each other.
3. The electromagnetic heater of claim 2, wherein The permanent magnet is an arc shape with the opening facing inward. A rubber pad is provided between the inner side of the permanent magnet and the outer side of the inlet pipeline. Each permanent magnet assembly is equipped with a clamp on the outer side.
4. The electromagnetic heater of claim 1, wherein The electromagnetic descaling assembly includes several turns of electromagnetic coils wound around the outside of the inlet pipeline; Or / and, it also includes a controller, with a differential pressure transmitter installed between the inlet pipe and the outlet pipe at the position corresponding to the left of the sealing plate. The differential pressure transmitter, electromagnetic coil, heating coil and drain valve are all connected to the controller.
5. The electromagnetic heater of claim 1 or 2 or 3 or 4, wherein A slag collection trough is fixedly installed on the lower inner side of the slag discharge shell corresponding to the position on the right side of the liquid inlet pipe. A sewage discharge hole connected to the sewage discharge pipeline is provided on the lower side of the slag collection trough. A perforated plate structure guide plate is fixedly installed between the slag collection trough and the slag discharge shell. Several through holes are staggered on the left side of the perforated plate structure guide plate. Or / and, a backwash outlet pipeline is fixedly connected to the outside of the inlet pipe at the left position of the protective shell. The other end of the backwash outlet pipeline passes through the outside of the heating descaling shell in a sealed manner. A backwash inlet pipeline connected to the outlet channel is fixedly connected to the outside of the left part of the heating descaling shell. Backwash control valves are installed on both the backwash inlet pipeline and the backwash outlet pipeline. An inlet valve is installed on the inlet pipeline at the left position of the sealing plate, and an outlet valve is installed on the outlet pipe.
6. The electromagnetic heater of claim 1 or 2 or 3 or 4 wherein The helix angle of the fins is 3° to 10°; Or / and, the fin material is stainless steel; Or / and, at least two lifting rings are provided on the upper outer side of the heating and descaling housing at intervals on the left and right, and at least two supports are provided on the lower outer side of the heating and descaling housing at intervals on the left and right.
7. The electromagnetic heater of claim 1 or 2 or 3 or 4 wherein The helix angle of the fins is 3° to 10°; Or / and, the fin material is stainless steel; Or / and, at least two lifting rings are provided on the upper outer side of the heating and descaling housing at intervals on the left and right, and at least two supports are provided on the lower outer side of the heating and descaling housing at intervals on the left and right.
8. A method of descaling for an electromagnetic heater as claimed in any one of claims 5 to 7, characterised in that The steps include the following: The first step is to collect the pressure difference between the inlet and outlet pipes. When the pressure difference is greater than the set value, the cleaning operation will begin. The second step is to close the inlet valve, outlet valve, electromagnetic coil, and heating coil. Third, open the drain valve to drain the electromagnetic heater and then close the drain valve. The fourth step is to connect the backwash inlet line to the cleaning equipment supply line and the backwash outlet line to the cleaning equipment return line. Fifth step: Open the backwash control valve, and the cleaning fluid of the cleaning equipment circulates between the electromagnetic heater and the cleaning equipment; Step 6: If the pressure difference is less than the set value within the set cleaning time, the rinsing operation is successful and rinsing stops; if the pressure difference is greater than or equal to the set value within the set cleaning time, the rinsing operation fails and proceeds to step 7. Step 7: After adding the cleaning agent into the cleaning equipment, perform acid washing on the electromagnetic heater; Step 8: If the differential pressure is less than the set value within the set cleaning time, the pickling operation is successful and the pickling is stopped; if the differential pressure is greater than or equal to the set value within the set cleaning time, the pickling operation fails and the cleaning operation is stopped.
9. The method of claim 8, wherein The cleaning equipment in step four includes a skid, a chemical storage tank, a reaction tank, a waste liquid tank, and a circulating pump. The chemical storage tank, reaction tank, and waste liquid tank are fixedly installed on the upper side of the skid from left to right. The circulating pump is fixedly installed on the upper right side of the skid, corresponding to the position behind the waste liquid tank. A return liquid pipeline is fixedly connected to the upper rear side of the reaction tank. A connecting pipeline is fixedly connected between the lower right side of the reaction tank and the inlet of the circulating pump. A supply liquid pipeline is fixedly connected to the outlet of the circulating pump. A dosing pipeline is fixedly connected between the chemical storage tank and the reaction tank, and a dosing valve is installed on the dosing pipeline. A waste liquid pipeline is fixedly connected between the reaction tank and the lower part of the waste liquid tank, and a drain valve is installed on the waste liquid pipeline. An overflow pipeline is fixedly connected between the upper part of the reaction tank and the waste liquid tank.
10. The descaling method according to claim 8 or 9, characterized in that... In the fourth step, the liquid supply line and the backwash inlet line, as well as the backwash outlet line and the return line of the cleaning equipment, are all connected by flexible hoses. Or / and, in step six, if the pressure difference is less than 0.05 MPa within 20 minutes, the flushing operation is successful and the flushing is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the flushing operation fails and proceeds to step seven. Or / and, in step eight, if the pressure difference is less than 0.05 MPa within 20 minutes, the pickling operation is successful and pickling is stopped; if the pressure difference is greater than or equal to 0.05 MPa within 20 minutes, the pickling operation fails and the cleaning operation is stopped. Or / and, in step seven, during the acid washing process, the pH value in the reaction chamber is 2-3.