Novel vertical multi-stage evaporation reboiler

Abstract

The utility model provides a novel vertical multi-stage evaporation reboiler which comprises a reboiler shell, a plurality of liquid collecting tanks are mounted in the reboiler shell, a gas channel is arranged between one end of each liquid collecting tank and the inner side of the reboiler shell, and a heat exchange tube is mounted in each liquid collecting tank; a feed liquid distributor is correspondingly arranged at the upper part of the uppermost liquid collecting tank or a feed liquid distributor is correspondingly arranged at the upper part of each liquid collecting tank; the feed liquid distributors are connected with the bottom of the reboiler shell through feed liquid pipelines; the lower part of the reboiler shell is connected with a liquid inlet pipeline, and the upper part of the reboiler shell is connected with a gas outlet pipeline; a plurality of liquid collecting tanks are designed, so that step-by-step heating of fluid can be realized; therefore, the reboiler has higher boiling heat transfer efficiency under a lower heat transfer temperature difference, the energy utilization rate is improved, and the application range of the reboiler is expanded; in addition, when the cold fluid can flow step by step, the uniform heat transfer effect is achieved.

Description

Technical Field

[0001] This application relates to the technical field of chemical equipment, and particularly relates to a novel vertical multi-stage evaporation reboiler. Background Art

[0002] A reboiler is a commonly used piece of equipment in industries such as petrochemical, food, and pharmaceutical industries. It is often used at the bottom of a distillation column. Its main function is to heat the bottom fluid to vaporize a part of the material and return it to the column, providing the heat required for fractionation, thereby improving the separation efficiency and playing an extremely important role.

[0003] In the process of chemical production, boiling heat transfer is a common heat exchange method, especially in applications where it is necessary to heat a fluid to its boiling point. However, the traditional kettle reboiler has a low heat transfer coefficient and is prone to fouling, and the installation height and hydrostatic column pressure of the vertical thermosiphon reboiler have limitations. Especially at a lower heat transfer temperature difference, the boiling heat transfer efficiency and operation stability of these devices are not ideal, restricting their application in industrial production.

[0004] This application aims to make improvements by combining the advantages of traditional kettle reboilers and horizontal thermosiphon reboilers, and proposes a novel vertical multi-stage evaporation reboiler, thereby achieving advantages such as uniform gas-liquid distribution, extended service life, not being prone to fouling, and improving boiling heat transfer efficiency.

[0005] After searching by the applicant, no prior art with relevant ideas has been found. Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Utility Model Content

[0006] The utility model provides a novel vertical multi-stage evaporation reboiler, including: a reboiler housing, a plurality of liquid collecting tanks are installed inside the reboiler housing, a gas channel is provided between one end of the liquid collecting tank and the inner side of the reboiler housing, a heat exchange tube is installed in each liquid collecting tank, and an overflow pipe is provided in each liquid collecting tank; a liquid distributor is correspondingly arranged above the uppermost liquid collecting tank, and the liquid distributor is connected to the bottom of the reboiler housing through a liquid pipeline; a liquid inlet pipeline is connected to the lower part of the reboiler housing, and a gas outlet pipeline is connected to the upper part of the reboiler housing.

[0007] As a preferred solution, the liquid inlet pipeline and the gas outlet pipeline are respectively connected to a distillation column.

[0008] As a preferred solution, along the direction from top to bottom of the reboiler housing, the gas channel gradually decreases.

[0009] As a preferred solution, a feed pump is provided on the liquid pipeline.

[0010] As a preferred solution, the liquid collecting tank adopts a square tank.

[0011] As a preferred solution, the sizes of the gas channels are all equal, and the gas channels are connected to the gas extraction pipeline through gas extraction branch pipelines.

[0012] A novel vertical multi-stage evaporation reboiler includes a reboiler housing. A plurality of liquid collection tanks are installed in the reboiler housing. A gas channel is provided between one end of the liquid collection tank and the inner side of the reboiler housing. Heat exchange tubes are installed in each liquid collection tank; a liquid distributor is correspondingly arranged above each liquid collection tank. The liquid distributor is connected to the bottom of the reboiler housing through a liquid pipeline; a liquid inlet pipeline is connected to the lower part of the reboiler housing, and a gas extraction pipeline is connected to the upper part of the reboiler housing.

[0013] As a preferred solution, the sizes of all the gas channels are all equal, and the gas channels are connected to the gas extraction pipeline through gas extraction branch pipelines.

[0014] As a preferred solution, along the direction from top to bottom of the reboiler housing, the gas channels gradually decrease.

[0015] As a preferred solution, the liquid inlet pipeline and the gas extraction pipeline are respectively connected to a distillation column.

[0016] As a preferred solution, a feed pump is provided on the liquid pipeline.

[0017] As a preferred solution, the liquid collection tank adopts a square tank.

[0018] As a preferred solution, an overflow pipe is provided in each liquid collection tank.

[0019] As a preferred solution, the liquid pipeline includes liquid distribution branch pipelines and a liquid distribution main pipeline. The liquid distribution branch pipelines are respectively connected to the liquid distributors and the liquid distribution main pipeline. The liquid distribution main pipeline is connected to the bottom of the reboiler housing; control valves are provided on each liquid distribution branch pipeline.

[0020] The utility model has the following advantages:

[0021] 1. The utility model designs a plurality of liquid collection tanks, which can realize the step-by-step heating of the fluid; it enables a high boiling heat transfer efficiency under a lower heat transfer temperature difference, improves the energy utilization rate, and expands the application range of the reboiler; in addition, when the cold fluid can flow step by step, a uniform heat transfer effect is achieved;

[0022] 2. The equipment is simple and efficient. Each liquid collection tank has independent heat exchange tubes and does not affect each other; the heat exchange tubes are immersed in the liquid collection tank, thereby ensuring that the heat exchange tubes are not easily fouled, can conduct heat transfer continuously, have a high heat transfer efficiency, can work stably for a long time, improve the operation stability of the equipment, and extend the service life of the equipment;

[0023] 3. The structure of this application is compact and occupies a small area, which is conducive to installation, transformation, and maintenance in existing factories.

[0024] 4. The design of the gas channel effectively reduces the hydrostatic column pressure and the energy consumption during equipment operation; moreover, the design of the gas channel is conducive to reducing the impact of the gas on the heat exchange tubes and lowering the gas flow resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of the first embodiment of this application;

[0026] Figure 2 is a schematic structural diagram of the second embodiment of this application in which the gas channels gradually decrease from top to bottom;

[0027] Figure 3 is a schematic structural diagram of the second embodiment of this application in which the gas channels are equal;

[0028] Figure 4 is of this application Figure 3 side sectional view;

[0029] Figure 5 is Figure 2 schematic structural diagram in cooperation with the rectifying column;

[0030] 1. Reboiler shell; 2. Liquid collection tank; 3. Gas channel; 4. Heat exchange tube; 5. Liquid distributor; 6. Feed pump; 7. Liquid inlet pipeline; 8. Rectifying column; 9. Gas extraction pipeline; 10. Liquid branch pipeline; 11. Liquid main pipeline; 12. Overflow pipe; 13. Gas extraction branch pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will describe in detail the specific embodiments of the present utility model with reference to the accompanying drawings. It should be noted that the specific embodiments described herein are only for explaining and illustrating the present utility model, and are not used to limit the present utility model.

[0032] Embodiment 1:

[0033] As Figure 1As shown in the figure, this embodiment provides a new type of vertical multi-stage evaporation reboiler, including: a reboiler housing 1, in which a plurality of liquid collecting tanks 2 are installed. The liquid collecting tank 2 is preferably a rectangular tank. The setting of the rectangular tank facilitates the installation of the heat exchange tubes 4, etc. The liquid collecting tank 2 is connected to the inner side of the reboiler housing 1 by welding or other means. A gas channel 3 is provided between one end of the liquid collecting tank 2 and the inner wall of the reboiler housing 1. A heat exchange tube 4 is installed in each liquid collecting tank 2. The heat exchange tube 4 and the liquid collecting tank 2 can be fixed by means of bracket connection, welding, bonding, etc. The heat exchange tube 4 adopts the heat exchange tube in the prior art, and the specific form is not limited. For example, it can adopt the heat exchange tube form in a kettle reboiler, or the heat exchange tube type in a horizontal thermosyphon reboiler. Those skilled in the art can choose according to the specific situation, and this application does not make specific limitations; in this embodiment, four liquid collecting tanks 2 are provided. The heat exchange tubes 4 arranged in the first liquid collecting tank 2 and the second liquid collecting tank 2 from bottom to top adopt the heat exchange tube form in a kettle reboiler. More specifically, the heat exchange tubes 4 arranged in the first liquid collecting tank 2 adopt the wound tube type in a kettle reboiler, and the heat exchange tubes 4 arranged in the second liquid collecting tank 2 adopt the U-tube type in a kettle reboiler; the heat exchange tubes 4 arranged in the third liquid collecting tank 2 and the fourth liquid collecting tank 2 adopt the heat exchange tube type in a horizontal thermosyphon reboiler; the heat exchange tubes 4 are immersed in the liquid collecting tank 2. This immersion method is beneficial to preventing the heat exchange tubes 4 from scaling, further improving the heat exchange efficiency, enhancing the operation stability of the equipment, and prolonging the service life of the equipment; the hot fluid enters the heat exchange tubes 4 and forms boiling heat transfer with the cold fluid in the liquid collecting tank 2; the overall internal heat integration of this embodiment improves the heat transfer efficiency, with high heat exchange efficiency and large processing capacity.

[0034] An overflow pipe 12 is arranged in each liquid collecting tank 2. The arrangement of the overflow pipe 12 is used to control the liquid level of the liquid collecting tank 2, enabling the material (cold fluid) to flow step by step and achieving a uniform heat transfer effect. A liquid distributor 5 is correspondingly arranged above the upper liquid collecting tank 2. The liquid distributor 5 can be a liquid distributor in the prior art. The liquid distributor 5 is connected to the bottom of the reboiler shell 1 through a liquid pipeline, and a feed pump 6 is arranged on the liquid pipeline. Only the liquid distributor 5 is arranged above the upper liquid collecting tank 2. In this case, complete cascade vaporization between the liquid collecting tanks 2 at all levels can be achieved. Heat can be distributed according to the temperature and pressure of different heating media, increasing the energy utilization rate. And only one liquid distributor 5 is arranged, ensuring the simplicity of the equipment structure. The lower part of the reboiler shell 1 is connected with a liquid inlet pipeline 7, and the liquid inlet pipeline 7 is used to connect with a distillation column 8 in cooperation. The upper part of the reboiler shell 1 is connected with a gas outlet pipeline 9, and the gas outlet pipeline 9 is connected with the distillation column 8. The material at the bottom of the distillation column 8 enters the reboiler shell 1 through the liquid inlet pipeline 7. Under the action of the feed pump 6, the material enters the upper liquid collecting tank 2 through the liquid pipeline and the liquid distributor 5. The heat exchange tubes 4 are filled with a hot fluid, and the heat exchange tubes 4 and the material (cold fluid) in the liquid collecting tank 2 form boiling heat transfer. The gas vaporized in the liquid collecting tank 2 is taken out through the gas outlet pipeline 9 at the top of the tower and then returned to the distillation column 8. This application can provide heat for the bottom of the distillation column 8, enabling partial vaporization of the liquid in the bottom of the tower. Along the direction from top to bottom of the reboiler shell 1, the gas channels 3 can gradually decrease. Because when working in the way of step-by-step boiling heat transfer, the cold fluid in the uppermost liquid collecting tank 2 is the most, and thus the vaporized gas is also the most. Therefore, it requires the largest gas channel 3. The cold fluid gradually decreases step by step downward, and the gas channels 3 gradually decrease. The arrangement of the gas channels 3 effectively reduces the static liquid column pressure, reduces the energy consumption of the overall equipment operation, and provides a direct rising path for the vaporized gas, which is beneficial to reducing the impact of the gas on the heat exchange tubes 4, reducing the gas flow resistance, and improving the heat transfer efficiency.

[0035] In this embodiment, the sizes of all the gas channels 3 can also be equal, that is, the distances between one end of the liquid collecting tank 2 and the inner wall of the reboiler shell 1 are all equal. In this case, the gas channels 3 are connected to the gas outlet pipeline 9 through gas outlet branch pipelines 13. Because after each vaporization, part of the gas is directly led out through the gas outlet branch pipelines 13 and does not need to all rise through the gas channels 3. Therefore, the gas channels 3 can be set to be equal, simplifying the structure of the equipment and facilitating processing.

[0036] The working principle of this embodiment is:

[0037] The feed liquid pipeline introduces the liquid at the bottom of the reboiler shell 1 into the feed liquid distributor 5, and the feed liquid distributor 5 introduces the material into the uppermost liquid collection tank 2. When the liquid covers the top of the heat exchange tubes 4 in the liquid collection tank 2, it flows step by step to the next-level liquid collection tank 2 through the overflow pipe 12 in the liquid collection tank 2. In each liquid collection tank 2, the cold fluid and the heat exchange tubes 4 form boiling heat transfer. When the gas channels 3 decrease successively from top to bottom, the gas vaporized in each liquid collection tank 2 rises and converges through the gas channels 3 and is taken out through the gas extraction pipeline 9 at the top of the tower; when the gas channels 3 are of equal size, part of the gas vaporized in each liquid collection tank 2 is directly taken out through the gas extraction branch pipeline 13 and does not need to rise through all the gas channels 3.

[0038] Embodiment 2:

[0039] The difference between this embodiment and Embodiment 1 lies in:

[0040] As Figure 2 、 Figure 3 shown, a feed liquid distributor 5 is correspondingly arranged at the upper part of each liquid collection tank 2, and the feed liquid distributor 5 can adopt a feed liquid distributor in the prior art.

[0041] The feed liquid pipeline includes feed liquid branch pipelines 10 and a feed liquid main pipeline 11. The feed liquid branch pipelines 10 are respectively connected to the feed liquid distributor 5 and the feed liquid main pipeline 11, and the feed liquid main pipeline 11 is connected to the bottom of the reboiler shell 1; a control valve (not shown in the figure) is arranged on each feed liquid branch pipeline 10; the control valve is used to control the flow rate of the feed liquid branch pipeline 10 and is controlled according to the flow rate of the material in the reboiler shell 1 tower kettle. If the material flow rate can ensure that each heat exchange tube 4 is immersed in the liquid collection tank 2, that is, the liquid level of each liquid collection tank 2 can cover the uppermost end of the heat exchange tube 4, at this time, all the control valves can be opened to distribute the material in the tower kettle to each liquid collection tank 2, and boiling heat transfer is carried out with the heat exchange tubes 4 in the liquid collection tank 2, and the gas vaporized in each liquid collection tank 2 is taken out through the gas extraction pipeline 9 and introduced into the distillation column 8; in this case, the overflow pipe 12 can be not set, and technicians can set it according to the specific situation.

[0042] When the material flow rate in the tower kettle is not enough to cover the top of the heat exchange tubes 4 in each liquid collection tank 2, the overflow pipe 12 needs to be set in this case. The material in the tower kettle is preferentially introduced into the uppermost liquid collection tank 2 and flows step by step to the next-level liquid collection tank 2 through the overflow pipe 12 in the liquid collection tank 2. In each liquid collection tank 2, the cold fluid and the heat exchange tubes 4 form boiling heat transfer, and the gas vaporized in each liquid collection tank 2 is taken out through the gas extraction pipeline 9 at the top of the tower;

[0043] More specifically, when the gas channels 3 decrease successively from top to bottom, the gas vaporized in each liquid collection tank 2 rises and converges through the gas channels 3 and is extracted through the gas extraction pipeline 9 at the top of the tower; when the gas channels 3 are of equal size, part of the gas vaporized from each liquid collection tank 2 is directly extracted through the branch gas extraction pipeline 13 and does not need to all rise through the gas channels 3.

[0044] In this embodiment, the feed liquid pipeline introduces the liquid at the bottom of the reboiler shell 1 into the feed liquid distributor 5, and the feed liquid distributor 5 evenly distributes the material into the liquid collection tanks 2, that is, evenly distributes the material onto the heat exchange tubes 4. In order to ensure a relatively high heat exchange intensity and strong production capacity, the feed liquid distributor 5 needs to evenly distribute the material to the outside of each tube of the heat exchange tubes 4 and also ensure uniformity along the length of each tube.

[0045] Embodiment Three:

[0046] The specific application of a new type of vertical multi-stage evaporation reboiler provided in this embodiment is as follows:

[0047] Using methanol vapor at a temperature of 72°C and a pressure of 0.137 MPa(A) as the heat source, evaporating the methanol-water mixed tower bottom liquid with a flow rate of 16.7 t / h, a liquid phase temperature of 61.7°C, and a pressure of 0.07 MPa(A) (methanol content 75%, water content 25%). The heat transfer load of the vertical multi-stage evaporation reboiler of the present application is 5800 KW. To achieve this heat transfer process, the corresponding equipment dimensions are: the diameter of the reboiler shell 1 is 4000 mm, and there are 4 identical liquid collection tanks 2 inside. The heat exchange area of the heat exchange tubes 4 in each liquid collection tank 2 is 450 m²; the present application reduces the temperature rise caused by the static liquid column, and at the same time has a relatively high gasification rate. The liquid phase circulation volume is smaller than that of forced circulation and falling film type reboilers, and the effective heat transfer temperature difference is higher than that of thermosyphon reboilers.

[0048] Embodiment Four:

[0049] This embodiment provides another form of specific application:

[0050] A methanol distillation energy-saving renovation project of an enterprise adopts the "improved three-tower three-effect" process. In order to improve the energy-saving effect, the methanol vapor at the top of the atmospheric column is used as the heat source for the pre-column reboiler; the specific parameters are as follows: the mass flow rate of the methanol vapor at the top of the atmospheric column is 28268 kg / h, the operating pressure is 0.08 MpaG, and the temperature is 79.8°C; the pressure at the bottom of the pre-column is 0.015 MpaG, the temperature is 71°C, and the required rising gas volume of the pre-column reboiler is 25964 kg / h.

[0051] Currently, the falling film reboiler used in this project has dimensions of DN2500*9000 mm and a heat exchange area of approximately 2088 m 2, the bottom column liquid circulation rate is 400 - 500 m 3 / h, and the size of the bottom column pump is 3500*1300*1300 mm; in order to optimize the equipment and reduce costs, we replace this falling film reboiler with the vertical multi-stage evaporator of the present application. In this embodiment, a five-stage evaporation design is adopted, that is, 5 liquid collecting tanks 2 are set, and corresponding heat exchange tubes 4 are respectively arranged in the 5 liquid collecting tanks. Preferably, the 5 heat exchange tubes 4 adopt the U-tube type in the kettle reboiler, and the heat exchange area of each stage of heat exchange tube 4 is about 400 m 2 , and the total heat exchange area is 2000 m 2 ; after the transformation, the bottom column liquid circulation rate is reduced to 40 - 60 m 3 / h, and the size of the bottom column pump is also reduced to 640*400*400 mm. This change significantly reduces the bottom column liquid circulation rate of the pre-column and greatly reduces the floor area; more importantly, the investment cost of the present application is about 80% lower than that of the falling film reboiler; therefore, the present application not only optimizes the equipment performance, reduces the occupied space, but also significantly saves the capital investment.

[0052] In summary, due to the adoption of the above technical solutions, the present application has the following advantages:

[0053] 1. The present application designs multiple liquid collecting tanks, which can realize the step-by-step heating of the fluid; enables a higher boiling heat transfer efficiency under a lower heat transfer temperature difference, improves the energy utilization rate, and expands the application range of the reboiler; in addition, when the cold fluid can flow step by step, a uniform heat transfer effect is achieved;

[0054] 2. The equipment is simple and efficient. Each liquid collecting tank has an independent heat exchange tube, which does not affect each other; the heat exchange tube is immersed in the liquid collecting tank, thereby ensuring that the heat exchange tube is not easy to scale, can continuously transfer heat, has a high heat transfer efficiency, can work stably for a long time, improves the operation stability of the equipment, and extends the service life of the equipment;

[0055] 3. The structure of the present application is compact and has a small floor area, which is beneficial to installation, transformation and maintenance in existing factories;

[0056] 4. The design of the gas channel effectively reduces the static liquid column pressure and reduces the energy consumption of the equipment operation; and the design of the gas channel is beneficial to reducing the impact of the gas on the heat exchange tube and reducing the gas flow resistance.

[0057] The devices, connection relationships, etc. not specifically described above all belong to the prior art, and the present utility model does not specifically elaborate on them here. They are all conventional technical means, and the present utility model does not specifically elaborate on them here. Those skilled in the art can make selections according to specific situations.

[0058] The preferred embodiments of the present application have been described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all fall within the protection scope of the present application.

[0059] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any appropriate manner. To avoid unnecessary repetition, various possible combination methods of the present application will not be described separately.

[0060] Furthermore, any combination can be made between various different embodiments of the present application, as long as it does not violate the idea of the present application, and it should also be regarded as the content disclosed in the present application.

Claims

1. A novel vertical multi-stage evaporation reboiler, comprising a reboiler housing (1), characterized in that, A plurality of liquid collecting tanks (2) are installed inside the reboiler shell (1). A gas passage (3) is provided between one end of the liquid collecting tank (2) and the inner side of the reboiler shell (1). Heat exchange tubes (4) are installed in each liquid collecting tank (2); an overflow pipe (12) is arranged in each liquid collecting tank (2). A liquid distributor (5) is correspondingly arranged above the uppermost liquid collecting tank (2). The liquid distributor (5) is connected to the bottom of the reboiler shell (1) through a liquid pipeline; the lower part of the reboiler shell (1) is connected with a liquid inlet pipeline (7), and the upper part of the reboiler shell (1) is connected with a gas outlet pipeline (9).

2. A novel vertical multi-stage evaporation reboiler according to claim 1, characterized in that, Along the direction from top to bottom of the reboiler shell (1), the gas passage (3) gradually decreases in sequence.

3. A novel vertical multi-stage evaporation reboiler according to claim 1, characterized in that, The sizes of the gas passages (3) are all equal. The gas passage (3) is connected to the gas outlet pipeline (9) through a gas outlet branch pipeline (13).

4. A novel vertical multi-stage evaporation reboiler according to claim 1, characterized in that, The liquid inlet pipeline (7) and the gas outlet pipeline (9) are respectively connected to the distillation column (8).

5. A novel vertical multi-stage evaporation reboiler, comprising a reboiler housing (1), characterized in that, A plurality of liquid collecting tanks (2) are installed inside the reboiler shell (1). A gas passage (3) is provided between one end of the liquid collecting tank (2) and the inner side of the reboiler shell (1). Heat exchange tubes (4) are installed in each liquid collecting tank (2). A liquid distributor (5) is correspondingly arranged above each liquid collecting tank (2). The liquid distributor (5) is connected to the bottom of the reboiler shell (1) through a liquid pipeline; the lower part of the reboiler shell (1) is connected with a liquid inlet pipeline (7), and the upper part of the reboiler shell (1) is connected with a gas outlet pipeline (9).

6. A novel vertical multi-stage evaporation reboiler according to claim 5, characterized in that, The sizes of the gas passages (3) are all equal. The gas passage (3) is connected to the gas outlet pipeline (9) through a gas outlet branch pipeline (13).

7. A novel vertical multi-stage evaporation reboiler according to claim 5, characterized in that, Along the direction from top to bottom of the reboiler shell (1), the gas passage (3) gradually decreases in sequence.

8. A novel vertical multi-stage evaporation reboiler according to claim 5, characterized in that, The liquid pipeline includes a liquid branch pipeline (10) and a liquid main pipeline (11). The liquid branch pipeline (10) is respectively connected to the liquid distributor (5) and the liquid main pipeline (11). The liquid main pipeline (11) is connected to the bottom of the reboiler shell (1); a control valve is arranged on each liquid branch pipeline (10).

9. A novel vertical multi-stage evaporation reboiler according to claim 5, characterized in that, An overflow pipe (12) is arranged in each liquid collecting tank (2).

10. A novel vertical multi-stage evaporation reboiler according to claim 5, characterized in that, The liquid inlet pipeline (7) and the gas outlet pipeline (9) are respectively connected to the distillation column (8).

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