A descaling system and cleaning method for plate heat exchangers used in non-purified calcium-type brine.

Abstract

This invention provides a descaling system and cleaning method for plate heat exchangers used with non-purified calcium-type brine, belonging to the field of plate heat exchanger cleaning technology. The descaling device specifically includes a plate heat exchanger assembly, a flow channel switching assembly, an online cleaning assembly, a storage and filling assembly, and an intelligent control center. The flow channel switching assembly is used to switch the main flow of brine between the first and second heat exchange flow channel units. The online cleaning assembly is used to perform online cleaning of the isolated heat exchange flow channel units through both physical flushing and chemical dissolution. The storage and filling assembly is used to store and fill the system with raw brine, heat exchange medium, cleaning fluid, and composite high-efficiency descaling agent. This system realizes non-disassembly online cleaning of the calcium sulfate scale layer on the plate heat exchanger during the preheating process of non-purified calcium-type raw brine, overcoming the defects of traditional manual disassembly, soaking, and brushing methods, such as high labor intensity, harsh working environment, and low efficiency.

Description

Technical Field

[0001] This invention belongs to the field of plate heat exchanger cleaning technology, specifically relating to a descaling system and cleaning method for plate heat exchangers used for non-purified calcium brine. Background Technology

[0002] A plate heat exchanger is a high-efficiency heat exchanger composed of a series of corrugated metal plates stacked together. Thin rectangular channels are formed between the plates, through which heat exchange occurs. Plate heat exchangers are ideal devices for liquid-liquid and liquid-gas heat exchange. They feature high heat exchange efficiency, low heat loss, compact and lightweight structure, small footprint, wide application, and long service life. Under the same pressure loss conditions, their heat transfer coefficient is 3-5 times higher than that of a tubular heat exchanger, their footprint is one-third that of a tubular heat exchanger, and their heat recovery rate can reach over 90%.

[0003] Analysis of existing plate heat exchangers revealed the following problems: The problem of difficult online removal of calcium sulfate scale: In existing technologies, during the preheating process of unpurified calcium-type brine, due to the solubility characteristics of calcium sulfate, dense calcium sulfate scale easily forms on the heat exchange surface. This scale is difficult to remove effectively by conventional online cleaning methods, usually requiring frequent shutdowns and disassembly of the heat exchanger for manual or chemical cleaning, leading to production interruptions, high labor intensity, and high operating costs.

[0004] The problems of continuously declining heat exchange efficiency and short operating cycles: As calcium sulfate scale accumulates on the plate surface, the thermal resistance of the heat exchanger increases, and the heat exchange efficiency drops sharply. At the same time, the scale reduces the flow area and increases flow resistance. Current technology lacks proactive and effective descaling methods, resulting in the need for equipment to be shut down for cleaning in a short period of time, making it impossible to achieve long-term, high-efficiency, continuous and stable operation.

[0005] Existing descaling technologies suffer from poor adaptability and low levels of intelligence: Some existing technologies rely on simple chemical dosing or basic physical cleaning, which are insufficient to accurately address the dynamic process of calcium sulfate scaling. There is a lack of an intelligent, integrated system capable of automatically switching flow channels, initiating cleaning, and adjusting scale inhibition parameters based on the scaling status, thus hindering proactive intervention and fully automated management of the scaling process. Summary of the Invention

[0006] In view of this, the present invention proposes a descaling system and cleaning method for plate heat exchangers used for non-purified calcium brine, which can solve the problems of easy scaling, low efficiency of descaling methods and difficulty in cleaning scale in traditional plate heat exchangers during the preheating treatment of non-purified calcium brine.

[0007] This invention is implemented as follows: This invention proposes a plate heat exchanger descaling system for non-purified calcium-type brine. The system specifically includes a plate heat exchanger assembly, a flow channel switching assembly, an online cleaning assembly, a storage and filling assembly, and an intelligent control center. The plate heat exchanger assembly includes a first heat exchange channel unit and a second heat exchange channel unit arranged in parallel. The flow channel switching component is used to switch the main flow of brine between the first heat exchange flow channel unit and the second heat exchange flow channel unit; The online cleaning component is used to perform online cleaning of the isolated heat exchange channel unit through a combination of physical flushing and chemical dissolution. The storage and filling component is used to store and fill the system with raw brine, heat exchange medium, cleaning fluid and composite high-efficiency descaling agent; The intelligent control center is used to collect system operation data and automatically control flow channel switching, online cleaning and addition of compound high-efficiency descaling agent according to the preset program and the collected data; The intelligent control center controls the flow channel switching component, so that the first heat exchange flow channel unit and the second heat exchange flow channel unit alternately enter the working state and the cleaning state, thereby realizing non-disassembly online cleaning.

[0008] Based on the above technical solution, the plate heat exchanger descaling system for non-purified calcium brine of the present invention can be further improved as follows: Furthermore, the heat exchange channel unit in the plate heat exchanger assembly includes an end plate and an inner plate; There are two end plates, located at the two ends of the heat exchange channel unit respectively; The inner plate is multiple and is clamped and fixedly installed between the two end plates; Both the end plate and the inner plate are provided with multiple large holes and multiple small holes for the flow of raw brine, heat exchange medium and cleaning liquid; The inner plate has recessed chambers on both sides, through which heat exchange medium and raw brine are respectively circulated, for preheating the raw brine. A baffle is provided around each hole on the inner plate to form a hole isolation cavity. A valve port is provided on the baffle, and a solenoid valve that can be controlled individually is sealed and fixed at the valve port to control the communication between the hole and the internal cavity of the inner plate.

[0009] Furthermore, the inner plate is a rectangular plate structure with a recessed flow channel structure on the periphery for installing a sealing ring; the top of the inner plate has a semi-through hole structure and the bottom has a semi-blind hole structure; when the two inner plates are symmetrically stacked, the two semi-through holes at the top are joined to form a through hole, and the two semi-blind holes at the bottom are joined to form a blind hole structure.

[0010] Furthermore, the online cleaning assembly includes a lead screw and a scraper threaded onto the lead screw; the lead screw and the scraper are located in a cavity formed by the inner plate, one end of the lead screw extends out and is connected to a gear transmission, multiple gears mesh with each other, and are driven by a drive motor through the motor gears to drive the scraper to move up and down reciprocally in the cavity.

[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the drive motor drives the lead screw to rotate in both directions, thereby driving the scraper to move up and down in the inner plate cavity, scraping and removing stubborn dirt inside the cavity.

[0012] Furthermore, the storage and filling assembly includes a static mixer, the two inlet ends of which are respectively connected to the raw brine transfer storage tank and the composite high-efficiency descaling agent storage tank, and the outlet end is connected to the raw brine inlet valve, for mixing the composite high-efficiency descaling agent with the raw brine online in a precise ratio and then sending it into the heat exchange channel unit in working condition.

[0013] Furthermore, the intelligent control center includes a controller, and a pressure transmitter, a temperature sensor, and a liquid conductivity sensor, which are electrically connected to the controller respectively; the pressure transmitter is used to detect the pressure difference between the inlet and outlet of the heat exchange channel unit, and the conductivity sensor is used to detect the conductivity of the outlet brine.

[0014] Furthermore, the intelligent control center is configured to automatically trigger a flow channel switching program when the inlet and outlet pressure difference of the heat exchange channel unit in operation reaches a preset threshold, switch the main brine flow to another heat exchange channel unit, and isolate the original working unit for online cleaning.

[0015] Furthermore, the flow channel switching assembly includes a raw brine inlet valve, a raw brine outlet valve, a heat exchange medium inlet valve, a heat exchange medium outlet valve, a cleaning fluid inlet valve, and a cleaning fluid outlet valve, respectively installed on the first heat exchange flow channel unit and the second heat exchange flow channel unit; the intelligent control center realizes the switching and isolation of the flow channels by controlling the opening and closing of the valves.

[0016] This invention also proposes a cleaning method for a plate heat exchanger descaling system for non-purified calcium-type brine. This method is applied to the aforementioned plate heat exchanger descaling system for non-purified calcium-type brine, and the specific steps of the method include: Normal heat exchange and scale inhibition stage: Brine mixed with composite high-efficiency descaling agent is introduced into the first heat exchange channel unit in operation for heat exchange, and the concentration of composite high-efficiency descaling agent is dynamically adjusted by the intelligent control center to delay scale formation; Flow channel switching trigger stage: When the inlet and outlet pressure difference of the first heat exchange flow channel unit reaches a preset threshold, the intelligent control center controls the flow channel switching component to seamlessly switch the main stream of brine to the second heat exchange flow channel unit and isolate the first heat exchange flow channel unit. Offline flow channel cleaning stage: The intelligent control center starts the online cleaning component and the storage and filling component to perform closed-loop circulation cleaning of the isolated first heat exchange flow channel unit by combining physical flushing and chemical dissolution until its flow channel pressure difference returns to the normal threshold. Flow channel reset and standby stage: After cleaning, the first heat exchange flow channel unit is purged and dried, and filled with brine to restore it to the normal pressure standby state, serving as a backup unit.

[0017] Furthermore, the offline flow channel cleaning stage specifically includes: using a servo motor to drive the screw to move the scraper back and forth inside the heat exchange flow channel unit to physically scrape the surface of the inner plate's internal chamber, while simultaneously using the chemical dissolution effect of the cleaning fluid to peel off the scale layer; after cleaning, the scraper is rinsed with clean water and then purged with dry gas in sequence.

[0018] Compared with existing technologies, the beneficial effects of the plate heat exchanger descaling system for non-purified calcium brine provided by this invention are: 1. Achieved long-cycle, uninterrupted continuous production: By setting up two parallel heat exchange channel units and using an intelligent control center to achieve seamless switching between the working channel and the standby channel, the system can still maintain normal operation while cleaning the scaled channel, completely solving the industry problem of frequent shutdowns and disassemblies due to cleaning, and providing a guarantee for the long-cycle continuous operation of the salt production unit.

[0019] 2. Significantly improved descaling efficiency and effectiveness: The online cleaning component combines physical scraping (a screw drives a scraper to move back and forth) with chemical dissolution, forming a dual-action mechanism. Compared to single chemical or physical cleaning, it can more efficiently and thoroughly peel off and dissolve calcium sulfate scale on the plate surface, quickly restoring the heat exchange efficiency and flow capacity of the flow channel.

[0020] 3. Achieved intelligent operation with active scale inhibition and precise control: The intelligent control center monitors key data such as differential pressure and conductivity in real time, dynamically adjusting the concentration of the compound high-efficiency descaling agent to delay scale formation at its source. Simultaneously, the system can automatically trigger flow channel switching and cleaning procedures based on preset differential pressure thresholds, forming a fully automated closed loop of "monitoring-judgment-switching-cleaning-reset," requiring no manual intervention and ensuring stable and reliable operation.

[0021] 4. Improved system stability and safety: After cleaning, the purging, drying and brine filling steps ensure that there is no residual moisture and gas in the standby flow channel, preventing secondary scaling, corrosion or air blockage, ensuring a smooth transition of system pressure and flow during flow channel switching, and improving the stability and safety of the entire preheating system. Attached Figure Description

[0022] Figure 1 This is a front axonometric view of the overall structure; Figure 2 This is a schematic diagram of the rear axonometric side of the overall structure; Figure 3 This is a top view of the overall structure; Figure 4 This is a partial structural diagram; Figure 5 This is a schematic diagram of a plate heat exchanger assembly. Figure 6 This is a cross-sectional view of a plate heat exchanger assembly. Figure 7 This is a schematic diagram of the inner panel and the online cleaning assembly. Figure 8 This is a schematic diagram of the end plate structure; Figure 9 This is a schematic diagram of the inner panel structure.

[0023] 1. Plate heat exchanger assembly; 11. End plate; 12. Inner plate; 121. Baffle; 122. Valve port; 13. Threaded rod; 14. Fastening nut; 2. Flow channel switching assembly; 211. Raw brine inlet valve one; 212. Raw brine inlet valve two; 213. Raw brine outlet valve one; 214. Raw brine outlet valve two; 221. Heat exchange medium inlet valve one; 222. Heat exchange medium inlet valve two; 223. Heat exchange medium outlet valve one; 224. Heat exchange medium outlet valve two; 231. Cleaning fluid inlet valve one; 232. Cleaning fluid inlet valve two; 233. Cleaning fluid outlet valve one; 234. Cleaning fluid outlet valve two; 24. Cover plate; 3. Online cleaning components; 31. Lead screw; 32. Scraper; 33. Gear; 34. Motor gear; 35. Drive motor; 4. Storage and filling components; 41. Heat exchange medium transfer and storage tank; 42. Cleaning fluid storage tank; 421. Fan; 43. Raw brine transfer and storage tank; 44. Composite high-efficiency descaling agent storage tank; 45. Static mixer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] As shown in the figure, this invention provides a descaling system for plate heat exchangers used with unpurified calcium-type brine. This system is a specially designed intelligent, online descaling key device addressing the industry problem of calcium sulfate scale easily precipitating on the heat exchange surface during the preheating process of unpurified calcium-type brine, leading to a sharp decline in heat exchange efficiency and requiring frequent shutdowns for disassembly and cleaning. It deeply integrates the principles of mechanical flow channel switching and descaling with composite high-efficiency descaling agents into the plate heat exchanger system, aiming to achieve proactive intervention and online removal of calcium sulfate scaling, thereby ensuring long-term, high-efficiency, stable, and continuous operation of the preheating system.

[0026] Specifically, the flow channel switching descaling system includes a plate heat exchanger assembly 1, a flow channel switching assembly 2, an online cleaning assembly 3, a storage and filling assembly 4, and an intelligent control center.

[0027] Among them, plate heat exchanger assembly 1 is used to preheat the non-purified calcium brine, providing a structural basis for descaling; flow channel switching assembly 2 is used to receive control commands from the intelligent control center to quickly switch the main flow channel of the brine, achieving seamless connection between the working flow channel and the standby flow channel; online cleaning assembly 3 is used to perform online circulating cleaning of the isolated scaled flow channel unit, dissolving and peeling off the calcium sulfate soft scale and loose scale layer deposited on the plate surface, restoring the heat exchange efficiency and flow capacity of the flow channel; storage and filling assembly 4 is used to store and retrieve non-purified calcium sulfate brine carrying composite high-efficiency descaling agent; the intelligent control center is used to collect the operating data of each unit of the device, and automatically trigger commands such as flow channel switching, online cleaning, and compound high-efficiency descaling agent addition and adjustment according to the preset program and the collected operating data, realizing full-process automation.

[0028] The plate heat exchanger assembly 1 consists of two parallel heat exchange channel units. These two heat exchange channel units are identical and, for ease of description, are referred to as heat exchange channel unit A and heat exchange channel unit B, respectively.

[0029] The heat exchange channel unit mainly consists of end plates 11 located at both ends and multiple inner plates 12 clamped and fixed between the two end plates 11. The two end plates 11 are fastened by threaded rods 13 and locking nuts 14.

[0030] The end plate 11 has five fluid flow holes, including four large holes and one small hole. The four large holes are located in the top and bottom areas of the end plate 11, two at the top and two at the bottom, for the flow of raw halogen and heat exchange medium. The one small hole is located in the middle of the end plate 11 for the flow of cleaning fluid. The holes on the end plate 11 are connected to the pipe wall and flange for easy connection to subsequent pipelines.

[0031] The inner plate 12 is stacked with the end plate 11. At positions completely corresponding to the large holes on the periphery and the small holes in the center of the end plate 11, the inner plate 12 has four large holes of identical size and position, and one small hole in the center, to ensure the unobstructed flow of the raw brine, heat exchange medium, and cleaning fluid. In addition, the inner plate 12 has an extra independent small hole, forming a dual-cleaning branch structure, which can achieve differentiated cleaning or independent flow of multiple cleaning fluids.

[0032] The inner plate 12 is a rectangular plate structure with recessed flow channels along both sides of its interior for the flow of heat exchange medium or halogen, achieving efficient heat exchange between the plate and the medium. When two identical inner plates 12 are symmetrically stacked, the semi-cavity flow channels of the two inner plates interlock to form a complete sealed chamber, providing continuous flow space for the medium.

[0033] The inner plate 12 has multiple sets of through holes, including large and small holes located at the four corners and the center of the plate. Each large and small hole is surrounded by an independent baffle 121. The baffle 121 is integrally formed with or sealed to the inner plate 12, forming a completely enclosed hole isolation cavity that completely separates the internal space of the hole from the recessed flow channel space of the inner plate 12. The height of the baffle 121 is the same as the depth of the recess inside the inner plate 12.

[0034] Each set of baffles 121 is provided with a valve port 122, and a solenoid valve is sealed and fixedly installed at the valve port 122. Each solenoid valve can be controlled independently, and the large hole, small hole and the internal cavity of the inner plate 12 can be connected through the solenoid valve.

[0035] The top of the inner panel 12 has a semi-through hole structure, and the bottom has a semi-blind hole structure. When the two inner panels 12 are symmetrically stacked, the two semi-through holes at the top are connected to each other to form a complete through hole, and the two semi-blind holes at the bottom are connected to each other to form a complete blind hole structure.

[0036] The flow channel switching assembly 2 includes multiple valves fixedly installed outside the large and small holes of the end plate 12, and a cover plate 24 for sealing the flow through the large hole of the end plate 12.

[0037] The valves include: a raw brine inlet valve 211 and a raw brine outlet valve 213 for the inlet and outlet of the raw brine; a heat exchange medium inlet valve 221 and a heat exchange medium outlet valve 223 for the inlet and outlet of the heat exchange medium; and a cleaning liquid inlet valve 231 and a cleaning liquid outlet valve 233 for the inlet and outlet of the cleaning liquid; the above valves are fixedly installed on the heat exchange flow channel unit A. Raw brine inlet valve 212 and raw brine outlet valve 214 are used for entering and exiting the raw brine; heat exchange medium inlet valve 222 and heat exchange medium outlet valve 224 are used for entering and exiting the heat exchange medium; and cleaning liquid inlet valve 232 and cleaning liquid outlet valve 234 are used for entering and exiting the cleaning liquid; the above valves are fixedly installed on the heat exchange flow channel unit B.

[0038] The online cleaning assembly 3 includes a lead screw 31 and two scrapers 32 threaded onto the lead screw 31. Both the lead screw 31 and the scrapers 32 are located within a cavity formed by two identical inner plates 12. The lead screw 31 is sealed within the inner plate 12 via bearings, with one end extending through a top through-hole formed by the two inner plates 12, and a gear 33 is fixedly mounted at the end. Multiple gears 33 mesh with each other, and one of the gears 33 also meshes with a motor gear 34. The motor gear 34 is fixedly mounted at the output end of a drive motor 35, which is fixedly mounted above the inner plate 12.

[0039] The storage and filling assembly 4 includes a heat exchange medium transfer storage tank 41 for storing and adding heat exchange medium to heat exchange channel units A and B. The inlet of the heat exchange medium transfer storage tank is connected to the condensate tank (not shown) of the salt making unit and is used to receive high-temperature condensate generated in the heating chamber of the salt making evaporator. It also includes a cleaning liquid storage tank 42 for storing and adding cleaning liquid to heat exchange channel units A and B; a raw brine transfer storage tank 43 for storing and adding raw brine to heat exchange channel units A and B; and a composite high-efficiency descaling agent storage tank 44 for storing and adding composite high-efficiency descaling agent to heat exchange channel units A and B.

[0040] The heat exchange medium inlet valve 1 221 and the heat exchange medium inlet valve 222 are connected to the bottom outlet of the heat exchange medium transfer and storage tank 41 through the same pipeline.

[0041] Heat exchange medium outlet valve 1 223 and heat exchange medium outlet valve 2 224 are connected to the outdoor air-cooled tower (not shown) through the same pipeline. After being cooled by the air-cooled tower, the heat exchange medium is discharged into the return ore water pool and finally pumped back to the rock salt mine by the return ore water pump as brine extraction water for the mine.

[0042] The cleaning fluid inlet valve 1 231 and the cleaning fluid inlet valve 2 232 are connected to the bottom outlet of the cleaning fluid storage tank 42 through the same pipeline.

[0043] The cleaning fluid inlet valve 1 231 and the cleaning fluid inlet valve 2 232 are connected to the cleaning fluid storage tank 42 by a pipe, and a valve is provided between the blower 421 and the pipe.

[0044] Cleaning fluid outlet valve 233 and cleaning fluid outlet valve 234 are connected to the cleaning fluid discharge area through the same pipeline, so as to discharge the cleaning fluid carrying dirt in an organized manner.

[0045] Raw brine inlet valve 1 (211) and raw brine inlet valve 2 (212) are connected to the outlet of static mixer 45 via the same pipe. One of the two inlets of static mixer 45 is connected to the outlet of raw brine transfer and storage tank 43 via a pipe. The inlet of raw brine transfer and storage tank is connected to the raw brine pump (not shown) of the salt production unit to receive low-temperature raw brine from rock salt mines. The other inlet is connected to the outlet of compound high-efficiency descaling agent storage tank 44 via a pipe. Using the mixing of static mixer 45, a measured amount of compound high-efficiency descaling agent is added to the raw brine in a specific ratio.

[0046] Raw brine outlet valve 1 212 and raw brine outlet valve 2 214 are connected to the main process pipeline through the same pipeline to provide preheated brine for subsequent process flows.

[0047] Both the raw brine transfer storage tank 43 and the compound high-efficiency descaling agent storage tank 44 are equipped with flow sensors at their outlets to detect the amount of liquid being transported, thus accurately quantifying the compound high-efficiency descaling agent contained in the raw brine.

[0048] The intelligent control center includes a controller for controlling the opening and closing of each valve, a pressure transmitter for detecting the pressure difference between the inlet and outlet liquids, a temperature sensor for detecting the temperature of the raw brine at the outlet, and a liquid conductivity sensor for detecting the conductivity of the brine at the outlet. All sensors are electrically connected to the controller.

[0049] Optionally, the inner wall of the inner plate 12 is provided with multiple grooves to improve heat conduction efficiency.

[0050] Optionally, an annular groove is provided around the recessed area inside the inner plate 12, and the same groove is provided at the same position on the end plate 11, for installing a sealing ring to achieve inter-plate sealing.

[0051] Based on the above system, the present invention also proposes a cleaning method for a plate heat exchanger descaling system for non-purified calcium brine, the method specifically including the following steps: Step 1: Normal Heat Exchange and Scale Inhibition Stage—Active scale inhibition as the core, achieving brine heat exchange + scale delay. System initialization: The intelligent control center adjusts the system to normal operation mode. The flow channel switching component 2 receives the command and opens the raw brine inlet valve 211 and raw brine outlet valve 213 of heat exchange flow channel unit A. Simultaneously, the heat exchange medium inlet valve 221 and heat exchange medium outlet valve 223 are opened. All other valves are closed, and heat exchange flow channel unit B is kept in standby state for filling raw brine. The online cleaning component and storage and filling component are in standby state.

[0052] Brine feed and compound high-efficiency descaling agent mixing: Non-purified calcium brine enters from the original brine transfer storage tank 43 and is injected into the static mixer 45 in a precise ratio with the descaling agent discharged from the compound high-efficiency descaling agent storage tank 44. The brine is then fully mixed in the static mixer 45 and directed into the heat exchange flow channel unit A through pipelines and switching valves.

[0053] Normal heat exchange operation: The brine containing the composite high-efficiency descaling agent flows in the inner plate 12 of the heat exchange channel unit A, and completes heat exchange with the heat exchange medium to preheat the brine. The preheated brine flows into the main process pipeline through the outlet and is transported to the downstream evaporation and crystallization system. The intelligent control center collects data such as the pressure difference ΔP, temperature and brine outlet conductivity of the inlet and outlet of the heat exchange channel unit A in real time through sensors, and continuously monitors the operating status.

[0054] Dynamic scale inhibition and adjustment: The control system dynamically adjusts the concentration of the compound high-efficiency descaling agent according to the change in conductivity of the brine outlet; if local micro-scale formation is detected, the short-term pulse backwash of the heat exchange channel unit A is immediately started to further inhibit scale accumulation.

[0055] In the above process, the intelligent control center precisely controls the opening and closing of the solenoid valves inside each valve port 122 in the inner plate 12, controlling the flow path of the raw brine and heat exchange medium inside the inner plate 12.

[0056] Step Two: Flow Channel Switching Trigger Stage – Using differential pressure threshold as the criterion, seamless flow channel switching and continuous production are achieved. Scaling status determination: As the operating time increases, a small amount of scale will slowly accumulate on the surface of the inner plate 12 of the heat exchange flow channel unit A, reducing the flow channel area and causing the inlet and outlet pressure difference ΔP to rise continuously. When ΔP reaches the threshold preset by the intelligent control center, the system determines that the scale has affected the heat exchange efficiency and flow capacity, and immediately triggers the flow channel switching procedure.

[0057] Rapid flow channel switching: The control system sends a linkage command to the intelligent flow channel switching valve group to complete two actions in a very short time: ① Open the raw brine inlet valve 212 and raw brine outlet valve 214 of heat exchange flow channel unit A, and the main flow of brine quickly switches from heat exchange flow channel unit A to heat exchange flow channel unit B. Heat exchange flow channel unit B immediately takes over to complete the brine preheating and heat exchange; ② Close the raw brine inlet valve 211 and raw brine outlet valve 213 of heat exchange flow channel unit A, completely isolating heat exchange flow channel unit A from the main brine process. At this time, heat exchange flow channel unit A is in offline state, and heat exchange flow channel unit B is in new working state.

[0058] Preparation before cleaning: After the valve group completes the switching, it continues to send instructions to heat exchange channel unit A to open the cleaning fluid inlet valve 231 and the cleaning fluid outlet valve 233 of heat exchange channel unit A, and close the redundant connection between heat exchange channel unit A and other components, so that heat exchange channel unit A forms an independent closed cleaning chamber to prepare for subsequent online cleaning; the intelligent control center simultaneously sends a cleaning start signal to the online cleaning components.

[0059] Step 3: Offline channel cleaning stage – physical flushing + chemical dissolution to achieve efficient scale removal and channel performance restoration. Cleaning parameter matching: The intelligent control center automatically determines the thickness and type of scale layer based on the pressure difference rise and running time of heat exchange channel unit A, sends instructions to the online cleaning components, and simultaneously starts the cleaning fluid storage tank 42 to match the corresponding cleaning medium, cleaning flow rate, circulation time and other parameters.

[0060] Closed-loop cleaning: After receiving the command, the online cleaning component starts the cleaning cycle. The drive motor 35 starts and drives the motor gear 34 to rotate in both directions. Through the meshing relationship, the gear 33 rotates, which in turn drives the lead screw 31 to rotate. Since the scraper 32 is threaded to the lead screw 31 and its rotation is limited by the inner plate 21, the scraper 32 moves up and down in the cavity inside the inner plate 21. With the help of the cleaning medium delivered by the cleaning fluid storage tank 42, the loose scale layer on the surface of the plate is peeled off and dissolved through the dual action of chemical dissolution and physical flushing.

[0061] Rinsing and Waste Liquid Treatment: When the cleaning cycle reaches the preset time, the intelligent control center monitors that the pressure difference in the heat exchange channel unit A has returned to the normal threshold. Then, the cleaning medium is switched to process condensate, and the heat exchange channel unit A is rinsed with clean water to remove residual cleaning agent and scale residue in the channel. The cleaning waste liquid and residue after rinsing are discharged into the dedicated waste liquid treatment system through the cleaning liquid outlet valve 233 to avoid environmental pollution.

[0062] Channel purging and drying: After rinsing, the online cleaning component stops supplying liquid and starts the blower 421 to introduce dry gas into the heat exchange channel unit A to thoroughly purge the residual liquid in the channel and prevent residual moisture in the channel from causing secondary scaling or plate corrosion.

[0063] Step 4: Flow channel reset and standby stage – Complete state reset, achieve cyclic switching + long-term stable operation Cleaning component disconnection: After the heat exchange channel unit A is purged, the intelligent control center issues a command, and the channel switching component 2 closes the valve connecting the heat exchange channel unit A and the cleaning fluid storage tank 42, disconnecting the cleaning channel and restoring the heat exchange channel unit A to its sealed state.

[0064] Channel reset filling: Channel switching component 2 opens the original brine inlet valve 211 of heat exchange channel unit A, slowly filling brine into unit A and discharging the purge gas in the channel until the channel of unit A is completely filled with brine and is in a normal pressure standby state.

[0065] Cyclic monitoring operation: After heat exchange channel unit A completes its reset, the intelligent control center marks it as a standby unit and continuously monitors the inlet and outlet pressure difference ΔP, temperature and other operating data of the current heat exchange channel unit B, repeating the normal heat exchange and scale inhibition process in step one; when the pressure difference ΔP of heat exchange channel unit B reaches the preset threshold, the system will trigger the switching procedure again to switch the main brine back to the cleaned heat exchange channel unit A, and perform offline cleaning on heat exchange channel unit B, thereby realizing the periodic cyclic switching and online cleaning of units A and B.

[0066] After offline cleaning, the flow channel is filled with brine to atmospheric pressure to avoid fluctuations in brine flow rate due to sudden pressure changes in the flow channel during switching, ensuring the smoothness of the switching process. At the same time, it prevents air from entering the channel and forming air resistance, which would affect the heat exchange efficiency.

[0067] By alternating operation and cleaning of the two parallel flow channel units A and B, any heat exchange unit is cleaned in time before the scale buildup reaches a level that affects production, thus maintaining the overall heat exchange system in a high-efficiency, low-resistance operating state and enabling long-term continuous operation of the salt production unit.

[0068] As the core command unit, the intelligent control center forms an automated closed loop that links the entire process of monitoring, judgment, switching, cleaning and reset. All actions are completed according to the preset logical sequence without human intervention, ensuring the stability and reliability of equipment operation.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A plate heat exchanger descaling system for non-purified calcium-type brine, characterized in that, Includes a plate heat exchanger assembly (1), a flow channel switching assembly (2), an online cleaning assembly (3), a storage and charging assembly (4), and an intelligent control center: The plate heat exchanger assembly (1) includes a first heat exchange channel unit and a second heat exchange channel unit arranged in parallel. The flow channel switching component (2) is used to switch the main flow of brine between the first heat exchange flow channel unit and the second heat exchange flow channel unit; The online cleaning component (3) is used for online cleaning of the isolated heat exchange channel unit by both physical flushing and chemical dissolution. The storage and filling component (4) is used to store and fill the system with raw brine, heat exchange medium, cleaning fluid and composite high-efficiency descaling agent; The intelligent control center is used to collect system operation data and automatically control flow channel switching, online cleaning and addition of compound high-efficiency descaling agent according to the preset program and the collected data; The intelligent control center controls the flow channel switching component (2) to make the first heat exchange flow channel unit and the second heat exchange flow channel unit alternately in working state and cleaning state, so as to realize non-disassembly online cleaning.

2. The plate heat exchanger descaling system for non-purified calcium-type brine according to claim 1, characterized in that, The heat exchange channel unit in the plate heat exchanger assembly (1) includes an end plate (11) and an inner plate (12). There are two end plates (11), located at the two ends of the heat exchange channel unit respectively; There are multiple inner plates (12), which are clamped and fixedly installed between two end plates (11); Both the end plate (11) and the inner plate (12) are provided with multiple large holes and multiple small holes for the flow of raw brine, heat exchange medium and cleaning liquid; The inner plate (12) has recessed chambers on both sides, through which heat exchange medium and raw brine are respectively circulated, for preheating the raw brine; A baffle (121) is provided around each hole on the inner plate (12) to form a hole isolation cavity. A valve port is provided on the baffle (121), and a solenoid valve that can be controlled independently is sealed and fixed at the valve port to control the communication between the hole and the internal cavity of the inner plate (12).

3. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 2, characterized in that, The inner plate (12) is a rectangular plate structure with a recessed flow channel structure for installing a sealing ring on the periphery; the top of the inner plate (12) is provided with a semi-through hole structure and the bottom is provided with a semi-blind hole structure; when the two inner plates (12) are symmetrically stacked, the two semi-through holes at the top are joined to form a through hole, and the two semi-blind holes at the bottom are joined to form a blind hole structure.

4. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 1, characterized in that, The online cleaning component (3) includes a lead screw (31) and a scraper (32) threaded onto the lead screw (31); the lead screw (31) and the scraper (32) are located in the cavity formed by the inner plate (12), one end of the lead screw (31) extends out and is connected to the gear (33) for transmission, multiple gears (33) mesh with each other and are driven by the drive motor (35) through the motor gear (34) to drive the scraper (32) to move up and down reciprocally in the cavity.

5. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 1, characterized in that, The storage and filling assembly (4) includes a static mixer (45). The two inlet ends of the static mixer (45) are respectively connected to the raw brine transfer storage tank (43) and the composite high-efficiency descaling agent storage tank (44), and the outlet end is connected to the raw brine inlet valve. It is used to mix the composite high-efficiency descaling agent with the raw brine online in a precise ratio and then send it into the heat exchange flow channel unit in working condition.

6. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 1, characterized in that, The intelligent control center includes a controller, and a pressure transmitter, a temperature sensor, and a liquid conductivity sensor, which are electrically connected to the controller respectively. The pressure transmitter is used to detect the pressure difference between the inlet and outlet of the heat exchange channel unit, and the conductivity sensor is used to detect the conductivity of the outlet brine.

7. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 6, characterized in that, The intelligent control center is configured to automatically trigger a flow channel switching program when the inlet and outlet pressure difference of a heat exchange channel unit in operation reaches a preset threshold, thereby switching the main brine flow to another heat exchange channel unit and isolating the original working unit for online cleaning.

8. A plate heat exchanger descaling system for non-purified calcium-type brine according to claim 1, characterized in that, The flow channel switching component (2) includes a raw brine inlet valve, a raw brine outlet valve, a heat exchange medium inlet valve, a heat exchange medium outlet valve, a cleaning fluid inlet valve, and a cleaning fluid outlet valve, which are respectively installed on the first heat exchange flow channel unit and the second heat exchange flow channel unit; the intelligent control center realizes the switching and isolation of the flow channels by controlling the opening and closing of the valves.

9. A cleaning method for a plate heat exchanger descaling system for non-purified calcium-type brine, applied to the plate heat exchanger descaling system for non-purified calcium-type brine as described in any one of claims 1-8, characterized in that, Includes the following steps: Normal heat exchange and scale inhibition stage: Unpurified raw brine containing calcium sulfate impurities is introduced into the first heat exchange channel unit in operation for heat exchange, and the concentration of compound high-efficiency descaling agent is dynamically adjusted by the intelligent control center to delay scale formation. Channel switching trigger stage: When the inlet and outlet pressure difference of the first heat exchange channel unit reaches the preset threshold, the intelligent control center controls the channel switching component (2) to seamlessly switch the main stream of brine to the second heat exchange channel unit and isolate the first heat exchange channel unit; Offline flow channel cleaning stage: The intelligent control center starts the online cleaning component (3) and the storage and filling component (4) to perform closed-loop circulation cleaning of the isolated first heat exchange flow channel unit by combining physical flushing and chemical dissolution until its flow channel pressure difference is restored to the normal threshold. Flow channel reset and standby stage: After cleaning, the first heat exchange flow channel unit is purged and dried, and filled with brine to restore it to the normal pressure standby state, serving as a backup unit.

10. The cleaning method for a plate heat exchanger descaling system for non-purified calcium-type brine according to claim 9, characterized in that, The offline flow channel cleaning stage specifically includes: driving the lead screw (31) through the drive motor (35) to drive the scraper (32) to move back and forth inside the heat exchange flow channel unit, physically scraping the surface of the inner chamber of the inner plate (12), and simultaneously peeling off the scale layer with the chemical dissolution effect of the cleaning liquid; after cleaning, the cleaning is carried out in sequence by rinsing with clean water and blowing with dry gas.

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