Cleansing device and method for a tube bundle of a cumene oxidation feed heater

Abstract

The cumene oxidation feed heater tube bundle cleaning device includes a shell-and-tube heater. The tube inlets of the shell-and-tube heater are connected to both an isopropylbenzene feed line and a solution feed line. The inlet of the solution feed line is connected to the outlet of the cleaning solution tank via a solution booster pump. The outlet of the shell-and-tube heater is connected to both an isopropylbenzene outlet line and a solution circulation line. The outlet of the solution circulation line is connected to a solution separation tank. The oil phase outlet of the solution separation tank is connected to the isopropylbenzene outlet line via an oil phase recovery line. The bottom outlet of the solution separation tank is connected to a sludge settling tank. The top outlet of the sludge settling tank is connected to the oil phase recovery line via an oil phase return line. The bottom outlet of the sludge settling tank is connected to a crystallization collection tank. The cleaning method includes cleaning solution preparation, high-pressure cleaning, and solution separation steps. This solution provides good sodium hydroxide crystallization cleaning effect, high cleaning efficiency, and low cost.

Description

Technical Field

[0001] This invention relates to the field of CHPPO production technology, specifically to a cleaning device and method for the tube bundle of the cumene oxidation feed heater. Background Technology

[0002] In the cumene oxidation unit of the CHPPO plant (a chemical production unit for producing propylene oxide from cumene via hydrogen peroxide), cumene feed is preheated to 80-90°C by a shell-and-tube heater at 0.8-0.9 MPaG and 65°C before entering the cumene oxidation reaction. The tube side carries the cumene material, while the shell side carries 0.4 MPaG heating steam. The heat exchange efficiency directly determines the rate, conversion rate, and stable operation of subsequent processes in the cumene oxidation reaction. To suppress side reactions in the cumene oxidation, a trace amount of sodium hydroxide is added to the raw material alkaline washing system as a solvent for washing phenol. However, during the operation of the shell-and-tube heater, the cumene material in the tube side is affected by factors such as temperature gradient changes, localized low flow rates, and varying concentrations of sodium hydroxide from the upstream feed. Sodium hydroxide is easily heated by superheated steam and readily crystallizes and precipitates on the inner wall of the tube bundle, gradually adhering and accumulating, causing narrowing of the tube flow channels or even localized blockage.

[0003] The accumulation of sodium hydroxide crystals within the tube bundle directly leads to a significant decrease in the effective utilization rate of the tube-side heat exchange area and an increase in material flow resistance. This not only prevents the preheating temperature of the cumene feed from reaching the process requirement of 80-90℃, severely affecting the oxidation reaction efficiency, but also causes a sharp increase in the pressure difference between the inlet and outlet of the shell-and-tube heater, triggering abnormal operating conditions such as equipment vibration. Existing methods for dealing with this sodium hydroxide crystal blockage mainly involve offline disassembly and cleaning of the shell-and-tube heater after it is removed from the system, or single-flow flushing after removal. Both methods require interrupting the normal heat exchange process, causing fluctuations in the production load of the cumene oxidation unit, high production costs due to reduced load, and the sodium hydroxide crystal blockage is prone to rapid re-formation after cleaning and restarting. Meanwhile, there is no existing technology that can adapt to the 0.8-0.9 MPaG cumene feed pressure condition without cutting off the online cleaning solution. It is impossible to complete the sodium hydroxide crystallization cleaning under the premise of maintaining normal feed and continuous heat exchange in the steam shell side of the shell and tube heater. Moreover, due to the high pressure characteristics of cumene feed, conventional low-pressure circulation schemes cannot achieve effective flow of the solution and crystallization contact in the tube bundle. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a cleaning device and method for the tube bundle of a cumene oxidation feed heater. This method can achieve sodium hydroxide crystallization cleaning without cutting out the tube heater, resulting in high cleaning efficiency and good effect, and effectively reducing production costs.

[0005] Sodium hydroxide crystals are water-soluble and have the characteristic of rapidly dissolving in alcohol-water mixtures. A high-pressure external dissolution and cleaning system can be added to the existing drainage structure of the cumene feed inlet pipeline of the shell-and-tube heater. Matching the cumene feed pressure of 0.8-0.9 MPaG, the online dissolution, circulation flushing and discharge of sodium hydroxide crystals in the tube bundle can be achieved without disconnecting the shell-and-tube heater and maintaining normal heat exchange, thus fundamentally solving the crystal blockage problem.

[0006] This invention provides the following technical solution: The cumene oxidation feed heater tube bundle cleaning device includes a shell-and-tube heater. The tube-side inlet of the shell-and-tube heater is connected to an isopropylbenzene feed line and a solution feed line, respectively. The inlet end of the solution feed line is connected to the outlet end of the cleaning solution tank via a solution booster pump. The outlet of the shell-and-tube heater is connected to an isopropylbenzene outlet line and a solution circulation line, respectively. The outlet end of the solution circulation line is connected to a solution separation tank. The oil phase outlet of the solution separation tank is connected to the isopropylbenzene outlet line via an oil phase recovery line. The bottom outlet of the solution separation tank is connected to a sludge settling tank. The top outlet of the sludge settling tank is connected to the oil phase recovery line via an oil phase return line. The bottom outlet of the sludge settling tank is connected to a crystallization collection tank. The shell side of the shell-and-tube heater is connected to a heat exchange line.

[0007] The technical solution of the present invention also includes that the feed end of the cleaning solution tank is connected to a solution preparation line and a hot water supply line, and the cleaning solution tank contains an alcohol-water mixed solution.

[0008] The technical solution of the present invention also includes that the tube side inlet of the shell-and-tube heater is connected to a three-way interface, and both the cumene feed line and the solution feed line are connected to the three-way interface.

[0009] The technical solution of the present invention also includes that the cumene feed pipeline and the cumene discharge pipeline are both equipped with differential pressure transmitters, the cleaning solution tank and the solution separation tank are both equipped with solubility sensors, and the differential pressure transmitters, concentration sensors and solution booster pumps are all connected to the PLC control cabinet.

[0010] The technical solution of the present invention also includes that the solution feed line, solution circulation line, cumene feed line, cumene discharge line, oil phase recovery line, and oil phase return line are all equipped with flow valves controlled by the PCL control cabinet, and the solution feed line is also equipped with a filter.

[0011] The technical solution of the present invention also includes that the cleaning solution tank is equipped with a stirring device, the effective volume of the cleaning solution tank is 0.5-1m3, the effective volume of the solution separation tank is 0.5-1m3, and the effective volume of the sewage settling tank is 0.5m3.

[0012] The technical solution of the present invention also includes that the tube side of the shell and tube heater, the cleaning solution tank, the solution separation tank, the solution feed pipeline, the solution circulation pipeline, the sewage settling tank, and the crystallization collection tank are all made of stainless steel.

[0013] The technical solution of the present invention also includes that the tube side of the shell-and-tube heater contains 0.8-0.9 MPaG of cumene at 65°C, and the shell side of the shell-and-tube heater contains 0.4 MPaG of steam.

[0014] A method for cleaning the tube bundle of a cumene oxidation feed heater includes the following steps: (1) Prepare the cleaning solution in the cleaning solution tank and turn on the stirring device. The cleaning solution is a mixture of alcohol and water. (2) Cumene enters the tube bundle of the shell-and-tube heater through the cumene feed line. The alcohol-water mixture solution is pressurized by the solution booster pump and then enters the tube bundle of the shell-and-tube heater through the solution feed line and flows in the same direction as the cumene. The pipeline pressure of the cumene feed line is 0.8-0.9 MPaG, and the pipeline pressure of the solution feed line is 1.0-1.2 MPaG. The shell side of the shell-and-tube heater is connected to the heat exchange pipeline. (3) Under high pressure, the alcohol-water mixture solution comes into full contact with the sodium hydroxide crystals adhering to and accumulating on the inner wall of the tube bundle, converting the sodium hydroxide crystals into a liquid alkaline solution and detaching them from the inner wall of the tube bundle; (4) The alkaline solution and cumene enter the solution separation tank together. The separated oil phase is discharged into the cumene discharge pipeline through the oil phase recovery line. The non-oil phase is discharged into the sewage settling tank through the bottom of the solution separation tank. The sewage settling tank uses the settling principle to transport the residual oil phase to the oil phase recovery line through the oil phase return line for oil phase recovery. The cleaning solution containing sodium hydroxide crystals is discharged into the crystallization collection tank.

[0015] As a preferred embodiment, the technical solution of the present invention further includes that the mass ratio of alcohol to water in the alcohol-water mixed solution is 5%-10% alcohol and 90%-95% water.

[0016] The beneficial effects of this invention are: (1) Achieve directional and efficient cleaning of sodium hydroxide crystals: In view of the water-soluble characteristics of sodium hydroxide crystals in the tube bundle, the solid sodium hydroxide crystals are rapidly and directionally dissolved by the alcohol-water mixed solution, and completely removed from the inner wall of the tube bundle. The cleaning efficiency is much higher than that of ordinary water washing. Moreover, the solution is compatible with the cumene system, with no secondary side reactions and no risk of equipment corrosion.

[0017] (2) Adaptable to high-pressure conditions, truly achieving online cleaning without cutting out: A 1.0-1.2 MPaG solution booster pump is used, matched with a 0.8-0.9 MPaG feed pressure for cumene, ensuring that the solution can effectively enter the tube bundle without the need for an additional feed bypass, the need to cut out the shell-and-tube heater, and without interrupting the main feed process of cumene. Under the premise that the shell-and-tube heater maintains normal steam heat exchange and the cumene oxidation unit continues to feed, the sodium hydroxide crystallization cleaning in the tube bundle is completed, which completely solves the problem of production load fluctuation and capacity loss caused by traditional cutting out cleaning. The capacity loss caused by cutting out cleaning can be reduced by ≥5% per year for a single heater, which is fully compatible with the continuous production requirements of the CHPPO unit.

[0018] (3) Adaptation to existing equipment: The original low-point drain port of the cumene feed inlet pipeline of the shell and tube heater is modified by a three-way valve. The main structure of the shell and tube heater is not changed, and the original heat exchange process of material flow in the tube side and steam flow in the shell side is not changed. The added cleaning module has a small installation space and low modification cost. It can be directly adapted to the shell and tube heater of the cumene oxidation unit of the existing CHPPO plant and has a wide range of industrial application value.

[0019] (4) High-pressure circulation does not interfere with the main process, and the cleaning process is safe and stable: The circulation pressure of the alcohol-water mixed solution is always higher than the pressure of the cumene main feed pipeline. The solution enters the tube bundle in the same direction as the main feed flow. The high-pressure circulation flow formed will not cause any interference to the material conveying and temperature control of the main process. During the cleaning process, the preheating effect of the shell and tube heater gradually recovers. There are no fluctuations in operating conditions and no safety risks, which meet the standard requirements for stable operation of chemical production.

[0020] (5) Dual protection of cleaning and prevention, greatly reducing the frequency of sodium hydroxide crystal blockage: It realizes the rapid and timely cleaning without cutting out after sodium hydroxide crystal blockage, reducing the local micro-aggregation, adhesion and accumulation of crystals from the root, reducing the frequency of sodium hydroxide crystal blockage in the tube bundle of the shell and tube heater by more than 80%, maintaining the heating effect for a long time, and controlling the fluctuation range of cumene discharge temperature within ±1℃, ensuring the efficient and stable progress of subsequent oxidation reactions.

[0021] (6) High degree of automation and convenient operation and maintenance: The entire device is fully automated by PLC control cabinet. From the judgment of sodium hydroxide crystal blockage to high-pressure circulation dissolution and cleaning, the whole process is automated. Only manual periodic inspection and replenishment of alcohol-water mixed solution are required. The maintenance cost is low and it is suitable for large-scale industrial application.

[0022] (7) No secondary pollution, centralized treatment of waste liquid: The alkaline waste liquid and a small amount of residue after dissolving sodium hydroxide crystals are uniformly discharged into the waste liquid collection and treatment system through the slag discharge valve to achieve centralized treatment. There is no on-site leakage or secondary pollution, which meets the environmental protection requirements of chemical production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the tube bundle cleaning device for the cumene oxidation feed heater in a specific embodiment.

[0025] Among them, 1 is a shell and tube heater, 2 is a three-way interface, 3 is a solution feed pipeline, 4 is a solution booster pump, 5 is a cleaning solution tank, 6 is a solution circulation pipeline, 7 is a solution separation tank, 8 is a sewage settling tank, 9 is a crystallization collection tank, 10 is a heat exchange pipeline, 11 is a differential pressure transmitter, 12 is a PCL control cabinet, 13 is a flow valve, and 14 is a filter. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0027] In the description of this invention, it should be understood that the terms "center", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this invention and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] As shown in the attached diagram, the cumene oxidation feed heater tube bundle cleaning device includes a tubular heater 1. The inlet of the tubular heater 1 is connected to a tee port 2. Both the cumene feed line and the solution feed line 3 are connected to the tee port 2. The inlet end of the solution feed line 3 is connected to the outlet end of the cleaning solution tank 5 via a solution booster pump 4. The inlet end of the cleaning solution tank 5 is connected to a solution preparation line and a hot water supply line. The cleaning solution tank 5 contains an alcohol-water mixed solution and is equipped with a stirring device. The effective volume of the cleaning solution tank 5 is 0.5-1 m³.

[0029] The outlet of the shell-and-tube heater 1 is connected to the cumene discharge pipeline and the solution circulation pipeline 6. The outlet of the solution circulation pipeline 6 is connected to the solution separation tank 7, which has an effective volume of 0.5-1 m3. The oil phase outlet of the solution separation tank 7 is connected to the cumene discharge pipeline through the oil phase recovery line. The bottom outlet of the solution separation tank is connected to the sludge settling tank 8, which has an effective volume of 0.5 m3. The top outlet of the sludge settling tank 8 is connected to the oil phase recovery line through the oil phase return line. The bottom outlet of the sludge settling tank 8 is connected to the crystallization collection tank 9. The shell side of the shell-and-tube heater 1 is connected to the heat exchange pipeline.

[0030] Both the cumene feed line and the cumene discharge line are equipped with differential pressure transmitters 11. The cleaning solution tank 5 and the solution separation tank 7 are each equipped with a solubility sensor. The differential pressure transmitters 11, concentration sensors, and solution booster pump 4 are all connected to the PLC control cabinet 12. The solution feed line 3, solution circulation line 6, cumene feed line, cumene discharge line, oil phase recovery line, and oil phase return line are all equipped with flow valves 13 controlled by the PLC control cabinet 12. The solution feed line 3 is also equipped with a filter 14.

[0031] The tubes of the tubular heater that come into contact with the alcohol-water mixture, the cleaning solution tank, the solution separation tank, the solution feed line, the solution circulation line, the sludge settling tank, and the crystallization collection tank are all made of stainless steel.

[0032] A method for cleaning the tube bundle of a cumene oxidation feed heater includes the following steps: (1) Prepare the cleaning solution in the cleaning solution tank and turn on the stirring device. The cleaning solution is an alcohol-water mixture with a mass ratio of 5%-10% alcohol and 90%-95% water. (2) Cumene enters the tube bundle of the shell-and-tube heater through the cumene feed line. The alcohol-water mixture solution is pressurized by the solution booster pump and then enters the tube bundle of the shell-and-tube heater through the solution feed line and flows in the same direction as the cumene. The pipeline pressure of the cumene feed line is 0.8-0.9 MPaG, and the pipeline pressure of the solution feed line is 1.0-1.2 MPaG. The shell side of the shell-and-tube heater is connected to the heat exchange pipeline. (3) Under high pressure, the alcohol-water mixture solution comes into full contact with the sodium hydroxide crystals adhering to and accumulating on the inner wall of the tube bundle, converting the sodium hydroxide crystals into a liquid alkaline solution and detaching them from the inner wall of the tube bundle; (4) The alkaline solution and cumene enter the solution separation tank together. The separated oil phase is discharged into the cumene discharge pipeline through the oil phase recovery line. The non-oil phase is discharged into the sewage settling tank through the bottom of the solution separation tank. The sewage settling tank uses the settling principle to transport the residual oil phase to the oil phase recovery line through the oil phase return line for oil phase recovery. The cleaning solution containing sodium hydroxide crystals is discharged into the crystallization collection tank.

[0033] The operating principle of this solution is as follows: The core of this solution is that the shell-and-tube heater remains operational without being shut down, and the main process continues to run. Under the premise that cumene feed passes normally through the tube side of the shell-and-tube heater and the shell side is continuously supplied with 0.4 MPaG steam for heat exchange, when sodium hydroxide crystal blockage is detected inside the tube bundle, an alcohol-water mixed dissolving solution is introduced through the inlet pipeline tee interface. This forms a high-pressure circulating dissolving flow in the tube bundle that is in the same direction as the main cumene feed flow. Utilizing the water solubility of sodium hydroxide crystals, the dissolving solution rapidly and directionally dissolves the sodium hydroxide crystals on the inner wall of the tube bundle during the circulation process. The dissolved alkaline solution is returned to the solution separation tank, realizing the online dissolution, flushing, and discharge of sodium hydroxide crystals until the shell-and-tube heater returns to normal operation.

[0034] The system is divided into a normal heating mode and a non-cut-out circulation cleaning mode. The two modes can be automatically switched by the PLC control cabinet according to the monitoring parameters. The switching process is undisturbed and does not affect the main production process of the CHPPO unit. The specific operation process is as follows: 1. Normal heating mode: The sodium hydroxide crystallization dissolution and cleaning module is in standby mode, the solution booster pump is stopped, and the flow valve and slag discharge valve are closed; cumene enters the tube side of the shell-and-tube heater, and 0.4 MPaG heating steam is introduced into the shell side. Through heat exchange between the shell-side steam and the tube-side cumene, the cumene is preheated to 80-90℃ and then sent to the oxidation reaction process; the condensate formed after steam heat exchange is discharged through the heat exchange pipeline; the PCL control cabinet monitors and collects parameters such as the inlet and outlet pressure difference of the shell-and-tube heater and the discharge temperature in real time. When all parameters are within the process threshold range, it is determined that there is no obvious accumulation of sodium hydroxide crystals in the tube bundle, and the system continues to maintain the normal heating mode.

[0035] 2. Non-cut-out circulation cleaning mode: When the online monitoring module detects that the pressure difference between the inlet and outlet of the cumene in the shell and tube heater is ≥0.3MPa, or the discharge temperature is below 80℃ and the shell-side steam flow has been adjusted to the maximum value, it is determined that sodium hydroxide crystals have accumulated in the tube bundle and formed a blockage. The PLC control cabinet automatically triggers the cleaning program, keeping the shell and tube heater non-cut-out throughout the process, the main cumene feed flow continues to run, and the shell side continuously passes 0.4MPaG steam for heat exchange.

[0036] The specific steps are as follows: (1) High-pressure liquid delivery: The PLC control cabinet issues a command to start the solution booster pump and slowly open the flow valve. The dissolution flow rate is automatically adjusted according to the pressure difference value (1-5 m³ / h, the flow rate is larger when the crystallization blockage is more serious). The alcohol-water mixed solution enters the feed inlet pipeline of the shell and tube heater from the original low point drain port through the precision filter and the three-way interface. Because the output pressure of the solution booster pump is higher than the pressure of the cumene feed pipeline, the alcohol-water mixed solution can effectively enter the tube bundle of 0.8-0.9 MPaG to form a high-pressure circulating dissolution flow without interfering with the material conveying and heat exchange of the main process.

[0037] (2) Directional dissolution and crystallization: The dissolving liquid flows in the same direction as the cumene main feed flow in the tube bundle and comes into full contact with the sodium hydroxide crystals attached and accumulated on the inner wall of the tube bundle. The water solubility of sodium hydroxide crystals is used to achieve rapid and directional dissolution, converting the solid sodium hydroxide crystals into a liquid alkaline solution and detaching them from the inner wall of the tube bundle.

[0038] (3) Continuous rinsing and solution renewal: The dissolved alkaline solution flows back to the solution separation tank in the low-pressure zone at the bottom of the tube bundle. The stirring device in the cleaning solution tank runs continuously to ensure uniform concentration of the solution and continuously dissolve the remaining sodium hydroxide crystals in the tube bundle. At the same time, the concentration sensor monitors the sodium hydroxide concentration in the solution separation tank in real time. If the concentration is ≥5%, it is determined that the solution has failed due to the dissolution of a large number of crystals. The PLC control cabinet automatically opens the slag discharge valve at the bottom of the solution separation tank and replenishes the storage tank with new alcohol-water mixed solution to ensure the crystal dissolution effect. It should also be noted that the discharge end of the tube side of the shell and tube heater can also be connected to the cleaning solution tank to achieve circulation cleaning.

[0039] (4) Shutdown and standby: When the pressure difference between the inlet and outlet of the tube heater drops below 0.1MPa and the discharge temperature returns to the process range of 80-90℃, it is determined that the sodium hydroxide crystals in the tube bundle have been cleaned up and the heat exchange effect has returned to normal; the PLC control cabinet automatically closes the flow valve, stops the solution booster pump, the system returns to the normal heating mode, and the sodium hydroxide crystal dissolution and cleaning module re-enters the standby state, waiting for the next cleaning trigger.

[0040] (5) Crystallization prevention: Set a timed micro-circulation program in the PLC control cabinet. Start the sodium hydroxide crystallization dissolution and circulation cleaning module every 6-8 hours for 5-10 minutes. Introduce the dissolving liquid into the tube bundle at a small flow rate of 1m³ / h to gently flush the inner wall of the tube bundle and remove the trace amount of sodium hydroxide crystals in time. Reduce the adhesion and accumulation of crystals from the source and reduce the frequency of blockage.

[0041] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. 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 also be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A cumene oxidation feed heater tube bundle cleaning apparatus characterized by, The system includes a shell-and-tube heater. The tube-side inlet of the shell-and-tube heater is connected to both an isopropylbenzene feed line and a solution feed line. The inlet end of the solution feed line is connected to the outlet end of a cleaning solution tank via a solution booster pump. The outlet of the shell-and-tube heater is connected to both an isopropylbenzene outlet line and a solution circulation line. The outlet end of the solution circulation line is connected to a solution separation tank. The oil phase outlet of the solution separation tank is connected to the isopropylbenzene outlet line via an oil phase recovery line. The bottom outlet of the solution separation tank is connected to a sludge settling tank. The top outlet of the sludge settling tank is connected to the oil phase recovery line via an oil phase return line. The bottom outlet of the sludge settling tank is connected to a crystallization collection tank. The shell side of the shell-and-tube heater is connected to a heat exchange line.

2. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The feed end of the cleaning solution tank is connected to a solution preparation line and a hot water supply line, and the cleaning solution tank contains an alcohol-water mixed solution.

3. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The tube-side inlet of the tubular heater is connected to a tee connector, and both the cumene feed line and the solution feed line are connected to the tee connector.

4. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The cumene feed line and cumene discharge line are both equipped with differential pressure transmitters. The cleaning solution tank and the solution separation tank are both equipped with solubility sensors. The differential pressure transmitter, concentration sensor, and solution booster pump are all connected to the PLC control cabinet.

5. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The solution feed line, solution circulation line, cumene feed line, cumene discharge line, oil phase recovery line, and oil phase return line are all equipped with flow valves controlled by the PCL control cabinet, and the solution feed line is also equipped with a filter.

6. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The cleaning solution tank is provided with a stirring device, and the effective volume of the cleaning solution tank is 0.5-1m 3 , the effective volume of the solution separation tank is 0.5-1m 3 , and the effective volume of the sewage sedimentation tank is 0.5m 3 .

7. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The tubes of the shell-and-tube heater, the cleaning solution tank, the solution separation tank, the solution feed line, the solution circulation line, the sewage settling tank, and the crystallization collection tank are all made of stainless steel.

8. The tube bundle cleaning device for the cumene oxidation feed heater as described in claim 1, characterized in that, The tube side of the shell-and-tube heater contains 0.8-0.9 MPaG of cumene at 65°C, and the shell side contains 0.4 MPaG of steam.

9. A method for cleaning the tube bundle of a cumene oxidation feed heater, characterized in that, Includes the following steps: Prepare the cleaning solution in the cleaning solution tank and turn on the stirring device. The cleaning solution is a mixture of alcohol and water. Cumene enters the tube bundle of the shell-and-tube heater through the cumene feed line. The alcohol-water mixture solution is pressurized by the solution booster pump and then enters the tube bundle of the shell-and-tube heater through the solution feed line, flowing in the same direction as the cumene. The pressure of the cumene feed line is 0.8-0.9 MPaG, and the pressure of the solution feed line is 1.0-1.2 MPaG. The shell side of the shell-and-tube heater is connected to the heat exchange line. Under high pressure, the alcohol-water mixture comes into full contact with the sodium hydroxide crystals adhering to and accumulating on the inner wall of the tube bundle, converting the sodium hydroxide crystals into a liquid alkaline solution that detaches from the inner wall of the tube bundle. The alkaline solution, along with cumene, enters the solution separation tank. The separated oil phase is discharged into the cumene discharge pipeline via the oil phase recovery line, while the non-oil phase is discharged into the sludge settling tank via the bottom of the solution separation tank. The sludge settling tank, through the principle of sedimentation, transports the residual oil phase to the oil phase recovery line via the oil phase return line for oil phase recovery. The cleaning solution containing sodium hydroxide crystals is discharged into the crystallization collection tank.

10. The cleaning method for the tube bundle of the cumene oxidation feed heater as described in claim 9, characterized in that, The mass ratio of alcohol to water in the alcohol-water mixture is 5%-10% alcohol and 90%-95% water.

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