A device for waste heat utilization of carbon dioxide reboiler

Abstract

The application provides a device for waste heat utilization of a carbon dioxide reboiler, and belongs to the field of waste heat utilization.The device for waste heat utilization of the carbon dioxide reboiler comprises a shell-and-tube heat exchanger, a heat storage buffer tank and a base for bearing, the shell side flow channel of the shell-and-tube heat exchanger is a compact flow channel with a small cross-sectional area, the tube side flow channel is a wide flow channel with a large cross-sectional area and capable of resisting fouling, the shell side flow channel of the shell-and-tube heat exchanger is connected with a waste heat fluid inlet pipe and a waste heat fluid outlet pipe, and the tube side flow channel of the shell-and-tube heat exchanger is connected with a cold material inlet pipe and a hot material outlet pipe.In the application, the flow direction of the waste heat fluid is flexibly regulated, the excess waste heat is stored for standby, and the waste heat is supplemented in time when the waste heat supply is insufficient, so that the waste heat is prevented from being wasted, the heating process of the tube side material is continuously and stably ensured, the heat transfer efficiency is strengthened by the heat exchange structure design, the heat exchange area requirement is reduced, and the energy utilization efficiency is further improved.

Description

Technical Field

[0001] This application relates to the field of waste heat utilization, and more specifically, to an apparatus for utilizing waste heat from a carbon dioxide reboiler. Background Technology

[0002] A carbon dioxide reboiler waste heat recovery device is a system that uses core equipment such as heat exchangers and waste heat boilers to recover the high-temperature waste heat generated during the operation of a carbon dioxide reboiler and convert it into hot water, steam, or directly for preheating raw materials as a secondary energy source. Its core function is to reduce energy waste and lower the overall energy consumption and carbon emissions of the device. It is commonly found in industrial scenarios such as chemical and refrigeration industries that rely on carbon dioxide reboilers.

[0003] In response, Chinese patent application number 201620848112.7 discloses a reboiler condensate waste heat recovery system, which includes a first preheater, a second preheater, a reboiler, a hot water tank, a transfer pump, and a column bottom. The reboiler is installed on one side of the lower end of the column bottom, and its upper outlet is connected to the lower part of the column bottom. The condensate outlet is connected to the heating tube inlet of the second preheater, and the heating tube outlet of the second preheater is connected to the upper inlet of the hot water tank. The heating tube outlet of the first preheater is connected to the condensate tank. One end of the first preheater is connected to a feed pipe, and the other end of the first preheater's discharge pipe is connected to the feed pipe of the second preheater via a pipeline. The discharge pipe of the second preheater is connected to the feed inlet of the column bottom. A transfer pump is installed on the pipeline between the hot water tank and the first preheater. The advantages of this reboiler condensate waste heat recovery system are: ingenious design, convenient use, low energy consumption, and improved production efficiency.

[0004] The above scheme also has the following shortcomings: Since the discharge of reboiler condensate is intermittent or fluctuating, the demand of waste heat users may also fluctuate. When the above device is used, it cannot synchronize the two, resulting in the recovery of heat being more or less, the system operation being unstable, and the average efficiency being low. Utility Model Content

[0005] To overcome the above shortcomings, this application provides a device for utilizing waste heat from a carbon dioxide reboiler, which aims to improve the problem of inconsistent heat recovery, which can easily lead to system instability.

[0006] This application provides a device for utilizing waste heat from a carbon dioxide reboiler, including a shell-and-tube heat exchanger, a heat storage buffer tank, and a base for support. The shell-side flow channel of the shell-and-tube heat exchanger is a compact flow channel with a small cross-sectional area, while the tube-side flow channel is a wide, anti-fouling flow channel with a large cross-sectional area. The shell-and-tube heat exchanger is connected to a waste heat fluid inlet pipe and a waste heat fluid outlet pipe, and the tube-side flow channel is connected to a cold material inlet pipe and a hot material outlet pipe.

[0007] In one specific implementation, the tube-side flow path of the shell-and-tube heat exchanger is composed of a large-diameter bare tube, the inner wall of which is coated with a polytetrafluoroethylene coating.

[0008] In the above process, the tube flow channel is composed of large-diameter bare tubes, coupled with a polytetrafluoroethylene coating on the inner wall, which further enhances the tube's anti-fouling and anti-corrosion capabilities, extends the service life of the shell-and-tube heat exchanger, and reduces cleaning and maintenance costs.

[0009] In one specific implementation, a flow meter is provided on the surface of the waste heat fluid inlet pipe, wherein an electromagnetic three-way valve is provided at the tail end of the flow meter, and a heat storage pipe is fixedly connected to the surface of the electromagnetic three-way valve, wherein the heat storage pipe is connected to the inlet of the heat storage buffer tank.

[0010] In the above implementation process, the flow rate of the waste heat fluid can be monitored in real time by the flow meter on the surface of the waste heat fluid inlet pipe. In conjunction with the electromagnetic three-way valve at the tail end and the heat storage pipe, the flow direction of the waste heat fluid can be flexibly controlled. Excess waste heat can be introduced into the heat storage buffer tank through the heat storage pipe to avoid waste heat and improve the flexibility of waste heat utilization in the system.

[0011] In one specific implementation, a circulating water pump is provided between the waste heat fluid inlet pipe and the heat storage buffer tank, wherein the inlet of the circulating water pump is connected to the outlet of the heat storage buffer tank through a pipe.

[0012] In the above implementation process, the outlet of the heat storage buffer tank is connected to the system pipeline by a circulating water pump, which can drive the circulation of the hot fluid stored in the heat storage buffer tank. When the flow rate of the waste heat fluid is insufficient, the waste heat in the tank can be supplemented to the shell and tube heat exchanger to ensure the stability of the heat exchange process and avoid fluctuations in the heating effect of cold materials.

[0013] In one specific implementation, a supplementary pipe is fixedly connected to the surface of the waste heat fluid inlet pipe at the tail end of the electromagnetic three-way valve, wherein the other end of the supplementary pipe is connected to the outlet of the circulating water pump.

[0014] In the above process, when the waste heat fluid flow rate is insufficient, the hot fluid delivered by the circulating water pump can be added to the waste heat fluid inlet pipe through the supplementary pipeline to maintain the stable flow rate of the shell-side fluid in the shell-and-tube heat exchanger.

[0015] In one specific implementation, the surface of the supplementary pipeline is provided with an electromagnetically controlled valve.

[0016] In the above process, by using electromagnetic control valves on the surface of the supplementary pipe, the opening and closing of the supplementary pipe and the amount of fluid supplemented can be precisely controlled, and the system can be flexibly adjusted according to the system requirements to avoid over- or under-supplementation and ensure the stable heat exchange efficiency of the shell-and-tube heat exchanger.

[0017] In one specific implementation, the heat storage buffer tank is equipped with a level gauge inside.

[0018] In the above process, the liquid level inside the heat storage buffer tank can be monitored in real time by the liquid level gauge inside the tank, which can prevent the liquid level from being too high and causing overflow or too low and affecting the normal pumping of the circulating water pump, thus ensuring the stable operation of the heat storage and heat replenishment structure composed of the heat storage buffer tank and the circulating water pump.

[0019] In one specific implementation, the surface of the flow meter is provided with a controller, wherein the flow meter, circulating water pump, electromagnetic control valve, electromagnetic three-way valve and level gauge are all electrically connected to the controller.

[0020] In the above implementation process, the controller on the surface of the flow meter is electrically connected to the flow meter, circulating water pump, electromagnetic control valve, electromagnetic three-way valve and level gauge. It can automatically collect flow and level data, synchronously control the operation of each component, realize the automated and intelligent operation of the system, and reduce manual intervention.

[0021] In one specific implementation, a spiral baffle is provided in the shell-side flow channel of the shell-and-tube heat exchanger.

[0022] In the above process, the flow path of the waste heat fluid in the shell side can be changed by the spiral baffles in the shell side of the shell heat exchanger, which increases the fluid disturbance, improves the heat transfer coefficient between the waste heat fluid and the tube side material, and further enhances the heat exchange efficiency of the shell heat exchanger.

[0023] Compared with the prior art, the beneficial effects of this application are as follows: 1. This application, by flexibly adjusting the flow direction of waste heat fluid, stores excess waste heat for later use, and replenishes it in a timely manner when the waste heat supply is insufficient, thereby avoiding waste of waste heat and ensuring the continuous and stable heating process of the tube-side material. Moreover, the heat exchange structure design can enhance heat transfer efficiency, reduce the heat exchange area requirement, and further improve energy utilization efficiency.

[0024] 2. This application extends the service life of equipment and reduces the frequency and cost of cleaning and maintenance through the anti-scaling and anti-corrosion design of the pipe. The system automatically collects data and coordinates the operation of each component through the controller, eliminating the need for real-time manual monitoring and operation. This reduces the cost of manual intervention and avoids system fluctuations caused by delays in manual operation, thereby improving the convenience and stability of overall operation. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the external structure provided in the embodiments of this application; Figure 2 Provided for the implementation of this application Figure 1 Enlarged structural diagram at point A in the middle; Figure 3 A front view structural diagram provided for an embodiment of this application; Figure 4 A top view of the structure provided for an embodiment of this application; Figure 5 Provided for the implementation of this application Figure 4 Enlarged structural diagram at point B; Figure 6 A side view structural diagram provided for an embodiment of this application; Figure 7 A schematic diagram of the disassembled structure of a shell-and-tube heat exchanger provided for an embodiment of this application; Figure 8 A schematic diagram of the internal structure of a shell-and-tube heat exchanger provided for an embodiment of this application.

[0027] In the diagram: 1. Shell-and-tube heat exchanger; 11. Waste heat fluid inlet pipe; 111. Flow meter; 112. Solenoid three-way valve; 113. Heat storage pipe; 12. Waste heat fluid outlet pipe; 13. Cold material inlet pipe; 14. Hot material outlet pipe; 15. Large-diameter bare pipe; 16. Spiral baffle; 2. Heat storage buffer tank; 3. Circulating water pump; 31. Make-up pipe; 311. Solenoid control valve; 4. Base. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0029] Please see Figure 1-8This application provides a device for utilizing waste heat from a carbon dioxide reboiler, including a shell-and-tube heat exchanger 1, a heat storage buffer tank 2, a base 4 for support, and a circulating water pump 3. The shell-side flow channel of the shell-and-tube heat exchanger 1 is a compact flow channel with a small cross-sectional area, suitable for conveying high-velocity waste heat fluid. A spiral baffle 16 is provided inside the shell-side flow channel of the shell-and-tube heat exchanger 1. The spiral baffle 16 is made of stainless steel and is stamped. Through the spiral baffle 16 inside the shell-side flow channel of the shell-and-tube heat exchanger 1, the lateral scouring of the waste heat fluid can be transformed into spiral flow, changing its flow path in the shell side, while enhancing the fluid turbulence, increasing fluid disturbance, improving the heat transfer coefficient between the waste heat fluid and the tube-side material, and reducing the heat exchange area requirement. Its tube-side flow channel is a wide anti-fouling flow channel with a large cross-sectional area, suitable for conveying materials that are prone to fouling, reducing the risk of fouling and blockage. Waste heat fluid inlet pipe 11 and waste heat fluid outlet pipe 12 are welded to both ends of the shell-side flow channel of the shell-and-tube heat exchanger 1, respectively.

[0030] A flow meter 111 is connected to the surface of the waste heat fluid inlet pipe 11 via a flange. The flow meter 111 can monitor the instantaneous flow rate of the waste heat fluid in real time and transmit the data to the controller. The tail end of the flow meter 111 is fixed with an electromagnetic three-way valve 112 via a thread. The electromagnetic three-way valve 112 is made of stainless steel and can quickly switch the fluid flow direction. One port of the electromagnetic three-way valve 112 is fixedly connected to a heat storage pipe 113 via a clamp. The heat storage pipe 113 is an insulated pipe to prevent heat loss. The end of the heat storage pipe 113 away from the electromagnetic three-way valve 112 is connected to the inlet of the heat storage buffer tank 2. The flow meter 111 on the surface of the waste heat fluid inlet pipe 11 can monitor the flow rate of the waste heat fluid in real time. When the flow rate exceeds the preset value, the controller triggers the electromagnetic three-way valve 112 to switch the flow direction. Excess waste heat can be introduced into the heat storage buffer tank 2 through the heat storage pipe 113 for storage, avoiding direct discharge and waste of waste heat, improving the flexibility of waste heat utilization in the system, and adapting to scenarios with fluctuating waste heat fluid flow.

[0031] A circulating water pump 3 is installed between the waste heat fluid inlet pipe 11 and the heat storage buffer tank 2. The pump body is made of cast iron, and the impeller is made of copper alloy, which is wear-resistant and corrosion-resistant. The shell-and-tube heat exchanger 1, the heat storage buffer tank 2, and the circulating water pump 3 are all fixedly installed on the base 4 with expansion bolts to ensure that the equipment does not shift during operation. The inlet of the circulating water pump 3 is connected to the outlet of the heat storage buffer tank 2 through a flanged pipe. The surface of the pipe is also covered with a heat insulation layer. The circulating water pump 3 connects the outlet of the heat storage buffer tank 2 to the system pipeline, which can drive the circulation of the hot fluid stored in the heat storage buffer tank 2. When the flow meter 111 detects that the flow rate of the waste heat fluid is insufficient, the controller starts the circulating water pump 3 to supplement the waste heat stored in the tank to the shell-side flow channel of the shell-and-tube heat exchanger 1 through the pipeline, ensuring the stability of the heating process of the cold material in the tube side and avoiding fluctuations in the heating effect of the cold material due to insufficient waste heat supply, which would affect the subsequent operating efficiency of the carbon dioxide reboiler.

[0032] The surface of the waste heat fluid inlet pipe 11 is fixedly connected to a replenishment pipe 31 via a tee joint at the tail end of the electromagnetic three-way valve 112. The replenishment pipe 31 is a seamless steel pipe of the same specification as the waste heat fluid inlet pipe 11 and is also wrapped with an insulation layer. The other end of the replenishment pipe 31 is connected to the outlet of the circulating water pump 3 via a flange. The replenishment pipe 31 forms a replenishment loop when the flow rate of the waste heat fluid is insufficient, accurately replenishing the hot fluid delivered by the circulating water pump 3 into the waste heat fluid inlet pipe 11, maintaining a stable flow rate of the shell-side fluid in the shell-and-tube heat exchanger 1, and avoiding the risk of sudden flow drops. To prevent a decrease in the heat transfer coefficient, an electromagnetic control valve 311 is installed on the surface of the supplementary pipe 31 via a flange. The electromagnetic control valve 311 is an electrically adjustable ball valve, and its opening can be remotely controlled by a controller. Through the electromagnetic control valve 311 on the surface of the supplementary pipe 31, the flow difference fed back by the flow meter 111 can be used to precisely control the opening and closing of the supplementary pipe 31 and the amount of fluid supplemented. This allows for flexible adjustment in accordance with the real-time needs of the system, avoiding over-supplementation that could cause the shell-and-tube heat exchanger 1 to overheat or under-supplementation that could lead to a decrease in heat exchange efficiency, thus ensuring the stable heat exchange efficiency of the shell-and-tube heat exchanger 1.

[0033] The tank wall of the heat storage buffer tank 2 is made of stainless steel with passivation treatment on the inner wall. It is wrapped with a 100mm thick polyurethane insulation layer on the outside, and the insulation layer is covered with a color steel plate protective layer to reduce heat loss inside the tank. A liquid level gauge is fixedly installed on the inner side wall of the heat storage buffer tank 2 through the bracket. The liquid level gauge inside the heat storage buffer tank 2 can monitor the liquid level of the fluid in the tank in real time and transmit the liquid level data to the controller. When the liquid level is too high, the controller will issue an alarm and close the heat storage channel of the electromagnetic three-way valve 112 to prevent the fluid from overflowing due to excessive liquid level. When the liquid level is too low, the controller will issue an alarm and reduce the output of the circulating water pump 3 to avoid damage to the circulating water pump 3 due to dry pumping, and ensure the stable operation of the heat storage and heat replenishment structure composed of the heat storage buffer tank 2 and the circulating water pump 3.

[0034] The shell-and-tube heat exchanger 1 has a cold material inlet pipe 13 and a hot material outlet pipe 14 welded to both ends of the tube-side flow channel. Both are seamless steel pipes. The weld joints with the tube-side flow channel are inspected for flaws to ensure a leak-free seal. The tube-side flow channel of the shell-and-tube heat exchanger 1 is composed of multiple large-diameter plain tubes 15 evenly arranged. The inner wall of the large-diameter plain tubes 15 is coated with a polytetrafluoroethylene (PTFE) coating by a spraying process. The PTFE coating has excellent corrosion resistance and non-stick properties. The arrangement of the large-diameter plain tubes 15 in the tube-side flow channel, combined with the PTFE coating on the inner wall, reduces material flow resistance and the probability of scale deposition. On the other hand, the PTFE coating prevents direct contact between the material and the tube wall, thus preventing corrosion and scale adhesion. This further enhances the tube-side anti-scaling and anti-corrosion capabilities, extends the service life of the shell-and-tube heat exchanger 1, and reduces the frequency and cost of regular cleaning and maintenance.

[0035] A controller is fixedly mounted on the surface of the flow meter 111 via a bracket. The controller housing is waterproof and dustproof. The flow meter 111, circulating water pump 3, electromagnetic control valve 311, electromagnetic three-way valve 112, and level gauge are all electrically connected to the controller. Through the controller on the surface of the flow meter 111, real-time data such as the flow rate of waste heat fluid and the level of the heat storage buffer tank 2 can be automatically collected. According to the preset program, the starting and stopping of the circulating water pump 3, the opening degree of the electromagnetic control valve 311, and the flow direction switching of the electromagnetic three-way valve 112 can be controlled synchronously to realize the automated and intelligent operation of the system. There is no need for real-time manual monitoring and operation, which reduces the cost of manual intervention and avoids system fluctuations caused by delays in manual operation, thereby improving the overall operational stability.

[0036] The working principle of this device for utilizing waste heat from a carbon dioxide reboiler is as follows: Waste heat fluid first enters through the waste heat fluid inlet pipe 11 of the shell-and-tube heat exchanger 1. A flow meter 111 on the surface of the waste heat fluid inlet pipe 11 monitors the flow rate in real time and transmits the data to the controller. If the flow rate exceeds a preset value, the controller triggers the electromagnetic three-way valve 112 at the end of the flow meter 111 to switch the flow direction. Part of the waste heat fluid is introduced into the heat storage buffer tank 2 via the heat storage pipe 113 for storage. If the flow rate is insufficient, the controller starts the circulating water pump 3 to replenish the waste heat inlet pipe 11 of the heat storage buffer tank 2 through the supplementary pipe 31, maintaining the flow rate of the shell-and-tube heat exchanger. The shell-side flow rate of heat exchanger 1 is stable. The waste heat fluid entering the shell-side of the shell-and-tube heat exchanger 1 flows in a spiral pattern under the action of the spiral baffle 16, which enhances the heat exchange with the cold material inside the large-diameter bare tube 15 of the tube side. The heated cold material is discharged through the hot material outlet pipe 14. After heat exchange, the waste heat fluid flows out from the waste heat fluid outlet pipe 12. At the same time, the liquid level gauge in the heat storage buffer tank 2 monitors the liquid level in real time and feeds it back to the controller. When the liquid level is too high, the electromagnetic three-way valve 112 heat storage channel is closed. When the liquid level is too low, the output of the circulating water pump 3 is reduced. The entire process is automatically coordinated by the controller to achieve efficient utilization of waste heat and stable operation of the system.

[0037] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A device for utilizing waste heat from a carbon dioxide reboiler, characterized in that, The heat exchanger includes a shell-and-tube heat exchanger (1), a heat storage buffer tank (2), and a base (4) for support. The shell-side flow channel of the shell-and-tube heat exchanger (1) is a compact flow channel with a small cross-sectional area, and the tube-side flow channel is a wide anti-fouling flow channel with a large cross-sectional area. The shell-and-tube heat exchanger (1) is connected to a waste heat fluid inlet pipe (11) and a waste heat fluid outlet pipe (12). The tube-side flow channel of the shell-and-tube heat exchanger (1) is connected to a cold material inlet pipe (13) and a hot material outlet pipe (14).

2. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 1, characterized in that, The tube-side flow path of the shell-and-tube heat exchanger (1) is composed of large-diameter bare tubes (15) arranged together, and the inner wall of the large-diameter bare tubes (15) is coated with polytetrafluoroethylene.

3. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 2, characterized in that, The surface of the waste heat fluid inlet pipe (11) is provided with a flow meter (111), wherein the tail end of the flow meter (111) is provided with an electromagnetic three-way valve (112), wherein the surface of the electromagnetic three-way valve (112) is fixedly connected with a heat storage pipe (113), wherein the heat storage pipe (113) is connected to the inlet of the heat storage buffer tank (2).

4. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 3, characterized in that, A circulating water pump (3) is provided between the waste heat fluid inlet pipe (11) and the heat storage buffer tank (2), wherein the inlet of the circulating water pump (3) is connected to the outlet of the heat storage buffer tank (2) through a pipe.

5. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 4, characterized in that, The surface of the waste heat fluid inlet pipe (11) is fixedly connected to a supplementary pipe (31) at the tail end of the electromagnetic three-way valve (112), wherein the other end of the supplementary pipe (31) is connected to the outlet of the circulating water pump (3).

6. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 5, characterized in that, The surface of the supplementary pipeline (31) is provided with an electromagnetic control valve (311).

7. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 6, characterized in that, The heat storage buffer tank (2) is equipped with a level gauge inside.

8. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 3, characterized in that, The surface of the flow meter (111) is provided with a controller, wherein the flow meter (111), the circulating water pump (3), the electromagnetic control valve (311), the electromagnetic three-way valve (112) and the level gauge are all electrically connected to the controller.

9. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 1, characterized in that, The shell-and-tube heat exchanger (1) is provided with a spiral baffle (16) in the shell-side flow channel.

10. The apparatus for utilizing waste heat from a carbon dioxide reboiler according to claim 1, characterized in that, The shell-and-tube heat exchanger (1), the heat storage buffer tank (2), and the circulating water pump (3) are all fixedly installed on the base (4).

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