Combined heat exchanger and heat exchange method

Abstract

The application provides a combined heat exchanger and heat exchange method, which comprises a first outer shell, a second outer shell, a first tube bundle, a second tube bundle and a gas-liquid separator; the first tube bundle is assembled in the first outer shell; one end of the first outer shell is provided with a tail gas inlet, and the other end is provided with a tail gas outlet; one side of the first outer shell is provided with a first back tube box; the gas-liquid separator is arranged in the first outer shell; the second outer shell is divided into a front shell and a rear shell by a partition plate; the second tube bundle is assembled in the front shell, the input end of the second tube bundle is connected with a condensate water inlet, and the output end is connected with a condensate water outlet; the rear shell is connected with the rear section of the other side of the first outer shell; the rear shell is provided with a cold air inlet; one side of the front shell is provided with a second back tube box, and the second back tube box is provided with a hot air outlet; the other side of the front shell is connected with the front section of the other side of the first outer shell. The application has the advantages that the waste heat of high-temperature tail gas and condensate water can be recovered simultaneously.

Description

[Technical Field]

[0001] This invention relates to the field of heat exchange equipment technology, and in particular to a combined heat exchanger and heat exchange method. [Background Technology]

[0002] Currently, pharmaceutical factories use hot air to dry drug raw materials. This typically involves heating air to a certain temperature using steam, and then delivering the heated air to drying equipment to dry the drug raw materials. The pharmaceutical process generates high-temperature exhaust gas, with a temperature of approximately 70°C. Simultaneously, during the steam heating of the air, the process steam condenses into water, which has a temperature of approximately 90°C.

[0003] In the past, high-temperature exhaust gases generated during pharmaceutical processes were directly released into the air. This not only polluted the environment but also increased the ambient temperature and wasted thermal energy. Similarly, condensate from process steam was currently discharged directly, resulting in significant waste of thermal energy. Of course, with the continuous improvement of people's environmental awareness, heat exchange equipment for recovering waste heat from high-temperature exhaust gas already exists. For example, Chinese utility model patent application number CN201820093348.3, filed on January 19, 2018, discloses a flue gas heat exchange device, including a horizontally arranged hollow tank-shaped main body. A tube is horizontally arranged in the space inside the main body, dividing it into an inner flue and an outer water channel. One end of the flue leads to the surface of the main body as a flue gas outlet. The upper side of the main body has at least one flue gas inlet, the front or rear side of the main body has at least one water inlet and at least one exhaust outlet, and the lower side of the main body has at least one water outlet. The surface of the water channel wall is provided with a spiral pattern, which can regulate the direction of water flow and prolong the time for water to flow through the entire water channel, allowing the water to absorb heat from the flue gas more fully. However, existing heat exchange equipment can only recover waste heat from high-temperature exhaust gas, but cannot simultaneously recover waste heat from condensate, resulting in a waste of thermal energy. [Summary of the Invention]

[0004] The technical problem to be solved by the present invention is to provide a combined heat exchanger and heat exchange method, which solves the problem that existing heat exchange equipment can only recover waste heat from high-temperature exhaust gas, but cannot simultaneously recover waste heat from condensate, resulting in waste of thermal energy.

[0005] This invention is implemented as follows:

[0006] In a first aspect, a combined heat exchanger includes a first outer shell, a second outer shell, a first tube bundle, a second tube bundle, and a gas-liquid separator, wherein the first outer shell and the second outer shell are arranged side by side;

[0007] The first tube bundle is assembled in the first outer shell; one end of the first outer shell is provided with an exhaust gas inlet, and the other end of the first outer shell is provided with an exhaust gas outlet; the first outer shell is provided with a first rear pipe box on the side away from the second outer shell; the gas-liquid separator is disposed in the first outer shell and is located at the end near the exhaust gas outlet.

[0008] The second outer shell is divided into a front shell and a rear shell by a partition plate; the second tube bundle is assembled in the front shell, the input end of the second tube bundle is connected to a condensate inlet, and the output end of the second tube bundle is connected to a condensate outlet.

[0009] The rear section housing is connected to the rear section on the other side of the first outer shell and serves as the first front tube box of the first outer shell; the rear section housing is provided with a cold air inlet and is connected to the first rear tube box through the first tube bundle; the front section housing is provided with a second rear tube box on the side away from the first outer shell and is provided with a hot air outlet; the other side of the front section housing is connected to the front section on the other side of the first outer shell and is connected to the first rear tube box through the first tube bundle.

[0010] Furthermore, the first tube bundle includes a first support tube plate fixed on both sides of the first outer shell, a first tube bundle bracket disposed in the first outer shell, and a plurality of stainless steel tubes disposed on the first tube bundle bracket; the two ends of the stainless steel tubes pass through the first support tube plates on both sides and are expanded and fixed to the first support tube plates.

[0011] Furthermore, the second tube bundle includes a second support tube sheet fixed at both ends of the front section shell, a second tube bundle support disposed inside the front section shell, and a plurality of heat exchange units disposed on the second tube bundle support from bottom to top.

[0012] Each heat exchange unit includes several rolled finned tubes and several U-shaped bends; each rolled finned tube is arranged along the width direction of the second tube bundle support, and one end of the first rolled finned tube serves as a water inlet and is connected to the condensate inlet, and one end of the last rolled finned tube serves as a water outlet and is connected to the condensate outlet, and adjacent rolled finned tubes are connected by the U-shaped bends.

[0013] Furthermore, one end of the front shell is fixed to a first insulation box on the outside of the second support tube plate, the first insulation box is filled with a first insulation material layer, and one end of the rolled finned tube extends into the first insulation box; the other end of the front shell is fixed to a second insulation box on the outside of the second support tube plate, the second insulation box is filled with a second insulation material layer, and the other end of the rolled finned tube extends into the second insulation box.

[0014] Furthermore, the condensate inlet and condensate outlet are located on opposite sides of the same end of the second tube bundle, and a water inlet collecting pipe is vertically arranged between the condensate inlet and the input end of the second tube bundle, and a water outlet collecting pipe is vertically arranged between the condensate outlet and the output end of the second tube bundle.

[0015] Furthermore, the condensate inlet is connected to the upper end of the inlet manifold, and a drain outlet is provided at the lower end of the inlet manifold; the condensate outlet is connected to the lower end of the outlet manifold, and a vent is provided at the upper end of the outlet manifold.

[0016] Furthermore, the gas-liquid separator includes an outer frame and several separation units arranged sequentially along the exhaust gas output direction;

[0017] Each separation unit includes a support rod and several separation plates mounted on the support rod, with an exhaust gas passage formed between two adjacent separation plates.

[0018] Furthermore, the bottom of the first outer shell is recessed downward near the gas-liquid separator to form a liquid collection tank, and the outside of the first outer shell is provided with a drain port that communicates with the liquid collection tank.

[0019] Furthermore, a third insulation material layer is provided at the bottom of the second tube bundle.

[0020] Secondly, a heat exchange method for a combined heat exchanger, the heat exchange method comprising the following steps:

[0021] The high-temperature exhaust gas generated by the pharmaceutical process is introduced into the first outer shell through the exhaust gas inlet at one end. The high-temperature exhaust gas passes through the gap between the stainless steel tubes of the first tube bundle and exchanges heat with the outer wall of the stainless steel tubes. The low-temperature exhaust gas after heat exchange is sent to the gas-liquid separator for gas-liquid separation. The low-temperature exhaust gas after gas-liquid separation is output through the exhaust gas outlet at the other end of the first outer shell. The condensate after gas-liquid separation falls down and collects at the bottom of the inner side of the first outer shell.

[0022] The condensate from the process steam is fed into the second tube bundle through the condensate inlet. The condensate passes through the rolled finned tubes of the second tube bundle and exchanges heat with the inner wall of the rolled finned tubes. The condensate after heat exchange is discharged through the condensate outlet.

[0023] The air to be heated is introduced into the first tube bundle through the cold air inlet of the rear shell. The air passes through the stainless steel tubes in the rear half of the first tube bundle and enters the first rear tube box. During this process, the air contacts and exchanges heat with the inner wall of the stainless steel tubes in the rear half, causing the air to heat up. The heated air then enters the stainless steel tubes in the front half of the first tube bundle from the first rear tube box, and contacts and exchanges heat with the inner wall of the stainless steel tubes in the front half, causing the air to heat up further. The further heated air then enters the front shell from the stainless steel tubes in the front half. After that, the air passes through the gaps between the rolled finned tubes of the second tube bundle and contacts and exchanges heat with the outer wall of the rolled finned tubes, causing the air to heat up again to obtain hot air. Finally, the hot air is output through the hot air outlet of the second rear tube box and enters the corresponding process pipeline.

[0024] By adopting the technical solution of the present invention, at least the following beneficial effects are achieved:

[0025] 1. By utilizing the cooling of high-temperature exhaust gas and condensate from process steam generated in pharmaceutical manufacturing, the heat generated during the cooling process of the high-temperature exhaust gas and condensate is transferred to the air through the first and second tube bundles. This heats the air required for drying the pharmaceuticals, which not only reduces the amount of steam and fuel needed to heat the air, but also enables the recovery and reuse of waste heat from the high-temperature exhaust gas and condensate, avoiding heat waste and achieving energy-saving effects; it also reduces pollution to the surrounding environment, which is beneficial to environmental protection.

[0026] 2. Excellent overall heat exchange performance. For heat exchange in the high-temperature exhaust gas section, a bare tube heat exchanger is used, allowing gas to convect on the inner and outer surfaces of the stainless steel tubes, thus achieving heat exchange between the high-temperature exhaust gas and the air. For heat exchange in the condensate section, a U-tube heat exchanger is used. Because the rolled finned tubes can disturb the fluid and continuously break the boundary layer, they have a better heat transfer coefficient, enhancing heat exchange performance. Furthermore, the integrated manifold within the rolled finned tubes improves pressure resistance. The combined use of the bare tube heat exchanger and the U-tube heat exchanger enhances heat exchange performance and ensures optimal heat exchange results.

[0027] 3. By integrating the bare tube heat exchanger and the U-tube heat exchanger into one heat exchange device, the waste heat of high-temperature exhaust gas and condensate can be recovered simultaneously. The overall structure is compact, small in size, and has a good sealing effect, which can reduce the overall footprint of the equipment and reduce production costs. [Attached Image Description]

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a front view of the combined heat exchanger of the present invention;

[0030] Figure 2 This is a left view of the combined heat exchanger of the present invention;

[0031] Figure 3 This is a top view of the combined heat exchanger of the present invention;

[0032] Figure 4 This is a front view of the second outer shell and the second tube bundle after assembly in this invention;

[0033] Figure 5 This is a left view of the second outer shell and the second tube bundle after assembly in this invention;

[0034] Figure 6 This is a top view of the second outer shell and the second tube bundle after assembly in this invention;

[0035] Figure 7 This is a front view of the second tube bundle in this invention;

[0036] Figure 8 This is a left view of the second tube bundle in this invention;

[0037] Figure 9 This is a top view of the second tube bundle in this invention;

[0038] Figure 10 This is a diagram of the welding structure between the second support tube sheet and the rolled finned tube in this invention;

[0039] Figure 11 This is a front view of the first outer shell and the first tube bundle after assembly in this invention;

[0040] Figure 12 This is a left view of the first outer shell and the first tube bundle after assembly in this invention;

[0041] Figure 13 This is a top view of the first outer shell and the first tube bundle after assembly in this invention;

[0042] Figure 14 This is a side view of the gas-liquid separator in this invention;

[0043] Figure 15 This is a top view of the gas-liquid separator in this invention;

[0044] Figure 16 This is a structural diagram of the separation plate in this invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] Combined heat exchanger 100;

[0047] First outer casing 1, exhaust gas inlet 11, exhaust gas outlet 12, first rear pipe box 13, first front pipe box 14, liquid collection tank 15, liquid outlet 16, second lifting lug 17.

[0048] Second outer shell 2, partition plate 21, front shell 22, rear shell 23, cold air inlet 231, second rear pipe box 24, hot air outlet 241;

[0049] First tube bundle 3, first support tube plate 31, first tube bundle bracket 32, first upper connecting plate 321, first lower connecting plate 322, stainless steel tube 33;

[0050] Second tube bundle 4, condensate inlet 41, condensate outlet 42, second support tube sheet 43, 431-weld point, second tube bundle bracket 44, heat exchange unit 45, rolled finned tube 451, U-bend 452, inlet water collection pipe 46, outlet water collection pipe 47, drain outlet 48, exhaust outlet 49, first lifting lug 40.

[0051] Gas-liquid separator 5, outer frame 51, separation unit 52, support rod 521, separation plate 522, vertical connecting plate 5221, inclined plate 5222, water collection hook 5223, exhaust gas passage 523;

[0052] First insulation box 61, first insulation material layer 62, second insulation box 63, second insulation material layer 64, third insulation material layer 65.

Detailed Implementation Methods

[0053] To better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] It should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing these embodiments and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0055] Example 1

[0056] Please see Figures 1 to 16 As shown, the present invention provides a combined heat exchanger 100, which includes a first outer shell 1, a second outer shell 2, a first tube bundle 3, a second tube bundle 4, and a gas-liquid separator 5. The first outer shell 1 and the second outer shell 2 are arranged side by side to facilitate the assembly of the first outer shell 1 and the second outer shell 2 together. In specific implementation, both the first outer shell 1 and the second outer shell 2 can be made of stainless steel.

[0057] The first tube bundle 3 is assembled inside the first outer shell 1; one end of the first outer shell 1 is provided with a tail gas inlet 11, and the other end of the first outer shell 1 is provided with a tail gas outlet 12; the first outer shell 1 is provided with a first rear tube box 13 on the side away from the second outer shell 2; the gas-liquid separator 5 is disposed inside the first outer shell 1 and located at the end near the tail gas outlet 12; in specific use, the high-temperature tail gas generated by the pharmaceutical process is transported to the first outer shell 1 through the tail gas inlet 11, and heat is exchanged through the outer wall of the first tube bundle 3 to transfer the high-temperature heat. The gas is transferred to the first tube bundle 3, and the replaced low-temperature exhaust gas enters the gas-liquid separator 5 for gas-liquid separation. During this process, the low-condensation-point odor gas in the exhaust gas will be released and become liquid. The separated low-temperature exhaust gas is discharged through the exhaust gas outlet 12 at the other end of the first outer shell 1. This not only realizes the recovery and utilization of the waste heat of the high-temperature exhaust gas, avoiding the waste of heat energy, but also reduces the pollution to the surrounding environment, which is beneficial to environmental protection. The separated liquid will drip down along the gas-liquid separator 5 and collect at the bottom of the inner wall of the first outer shell 1 for unified discharge.

[0058] The second outer shell 2 is divided into a front shell 22 and a rear shell 23 by a partition plate 21. The second tube bundle 4 is assembled in the front shell 22. The input end of the second tube bundle 4 is connected to a condensate inlet 41, and the output end of the second tube bundle 4 is connected to a condensate outlet 42. In actual use, the condensate from the process steam of the pharmaceutical plant is transported to the second tube bundle 4 through the condensate inlet 41. During the flow of the condensate through the second tube bundle 4, the high-temperature heat is transferred to the second tube bundle 4. The low-temperature condensate after heat exchange is output through the condensate outlet 42 of the second tube bundle 4. In this way, the waste heat of the condensate of the process steam can be recovered and utilized, avoiding the waste of heat energy.

[0059] The rear section housing 23 is connected to the rear section on the other side of the first outer shell 1 and serves as the first front tube box 14 of the first outer shell 1. The rear section housing 23 is provided with a cold air inlet 231, and the rear section housing 23 is connected to the first rear tube box 13 through the first tube bundle 3. In this way, after the air to be heated is sent into the rear section housing 23 through the cold air inlet 231, the air can be transported to the first rear tube box 13 along the rear half of the first tube bundle 3. During this process, since high-temperature exhaust gas is introduced into the outside of the first tube bundle 3, the high-temperature exhaust gas will transfer heat to the first tube bundle 3. Therefore, when the air passes through the interior of the rear half of the first tube bundle 3, the rear half of the first tube bundle 3 will transfer heat to the air, thereby achieving preliminary heating of the air.

[0060] The front housing 22 has a second rear tube box 24 on the side away from the first outer housing 1, and the second rear tube box 24 has a hot air outlet 241. The other side of the front housing 22 is connected to the front section of the other side of the first outer housing 1, and the front housing 22 is connected to the first rear tube box 13 through the first tube bundle 3. In this way, the air that has been preheated will enter the first half of the first tube bundle 3 from the first rear tube box 13, and then enter the front housing 22. During this process, because high-temperature exhaust gas is introduced into the outside of the first tube bundle 3, and the high-temperature exhaust gas will pass through the first half of the first tube bundle 3 after entering the first outer housing 1, the temperature of the first half of the first tube bundle 3 will be higher than that of the rear half. Therefore, the preheated air... As the air passes through the interior of the first half of the tube bundle 3, it continues to transfer heat to the air, thus further heating the air. After entering the front shell 22, the further heated air passes through the outside of the second tube bundle 4. Since the second tube bundle 4 contains condensate from the pharmaceutical process steam, and the temperature of the condensate is higher than the temperature of the high-temperature exhaust gas generated by the pharmaceutical process, the second tube bundle 4 transfers heat to the air as it passes through the outside of the second tube bundle 4, thus further heating the air. The resulting hot air is then output through the hot air outlet 241 to the corresponding process pipeline, for example, to be transported to boiler steam for reheating, so as to use the high-temperature air to dry the medicine.

[0061] In a preferred embodiment of the present invention, the first tube bundle 3 includes a first support tube plate 31 fixed on both sides of the first outer shell 1, a first tube bundle support 32 disposed within the first outer shell 1, and a plurality of stainless steel tubes 33 disposed on the first tube bundle support 32; the two ends of the stainless steel tubes 33 pass through the first support tube plates 31 on both sides and are expanded and fixed to the first support tube plates 31 to support the stainless steel tubes 33. In specific implementation of the present invention, the stainless steel tubes 33 and the first support tube plates 31 can be fixedly connected together by strength expansion or strength expansion + welding to ensure that the first support tube plate 31 and the stainless steel tubes 33 are in close contact and are not affected by thermal expansion and contraction, thereby ensuring the sealing between the ends of the stainless steel tubes 33 and the first support tube plate 31. The first tube bundle 3 can be divided into a front half tube bundle and a rear half tube bundle, wherein the front half tube bundle is connected to the interior of the front section shell 22, and the rear half tube bundle is connected to the interior of the rear section shell 23.

[0062] In a preferred embodiment of the present invention, the first tube bundle support 32 includes a first upper connecting plate 321 connecting the upper ends of the two first support tube plates 31 and a first lower connecting plate 322 connecting the lower ends of the two first support tube plates 31. This not only better supports the first tube bundle 3, but also allows the high-temperature exhaust gas to pass through the gap between the first tube bundle 3 better during operation, thereby ensuring the heat exchange effect.

[0063] In a preferred embodiment of the present invention, the second tube bundle 4 includes a second support tube plate 43 fixed at both ends of the front housing 22, a second tube bundle support 44 disposed within the front housing 22, and a plurality of heat exchange units 45 disposed from bottom to top on the second tube bundle support 44, so as to increase the heat exchange area and improve the heat exchange effect. In a specific implementation, the second tube bundle support 44 includes a second upper connecting plate 431 connecting the upper ends of the two second support tube plates 43 and a second lower connecting plate 432 connecting the lower ends of the two second support tube plates 43. This can better support the second tube bundle 4 and allow air to pass through the gaps between the second tube bundle 4 better during operation, thereby ensuring the heat exchange effect.

[0064] Each heat exchange unit 45 includes several rolled finned tubes 451 and several U-shaped bends 452. Each rolled finned tube 451 is arranged along the width direction of the second tube bundle support 44. One end of the first rolled finned tube 451 serves as an inlet and is connected to the condensate inlet 41. One end of the last rolled finned tube 451 serves as an outlet and is connected to the condensate outlet 42. Adjacent rolled finned tubes 451 are connected by the U-shaped bends 452. In a preferred embodiment of the present invention, each heat exchange unit 45 includes at least four rolled finned tubes 451 and at least three U-shaped bends 452. Except for one end of the first and last rolled finned tubes 451, adjacent rolled finned tubes 451 are connected end-to-end by U-shaped bends 452. In practical implementation, both ends of each rolled finned tube 451 pass through the second support tube plate 43, and the rolled finned tube 451 is welded and fixed to the second support tube plate 43 on the outside of the second support tube plate 43 by weld points 431. That is, a ring of weld points 431 is welded to the outside of the second support tube plate 43. Figure 10 As shown, this ensures both sturdiness and airtightness.

[0065] This invention designs the entire second tube bundle 4 to include several heat exchange units 45 mounted on a second tube bundle support 44 from bottom to top. Each heat exchange unit 45 includes several rolled finned tubes 451 and several U-shaped bends 452, connecting adjacent rolled finned tubes 451 through the U-shaped bends 452. In practical use, when the condensate from the process steam enters each heat exchange unit 45, the condensate flows through multiple rolled finned tubes 451 before being output, thus greatly improving the heat exchange efficiency and effectively recovering the waste heat of the condensate. It also makes the structure of the entire second tube bundle 4 more compact, thereby helping to reduce the floor space required. Meanwhile, since the heat exchange unit 45 uses rolled finned tubes 451, which have an extended secondary heat transfer surface (rolled surface), the heat transfer process occurs not only on the primary heat transfer surface (heat exchange tube) but also on the secondary heat transfer surface. In this way, the heat of the high-temperature side medium (i.e., condensate) is not only introduced to the low-temperature side medium through the primary surface, but also transferred along the direction of the rolled surface. That is, along the direction of the rolled surface, the heat is introduced by the heat exchange tube and then transferred to the low-temperature side medium by convection, thus further improving the heat exchange effect.

[0066] In a preferred embodiment of the present invention, one end of the front shell 22 is fixedly provided with a first insulation box 61 on the outside of the second support tube plate 43, the first insulation box 61 is filled with a first insulation material layer 62, and one end of the rolled finned tube 451 extends into the first insulation box 61; the other end of the front shell 22 is fixedly provided with a second insulation box 63 on the outside of the second support tube plate 43, the second insulation box 63 is filled with a second insulation material layer 64, and the other end of the rolled finned tube 451 extends into the second insulation box 63. Because the two ends of the rolled finned tube 451 in the second tube bundle 4 need to be supported, and the beginning and end of two adjacent rolled finned tubes 451 need to be connected by a U-shaped elbow 452, the first insulation material layer 62 is used to insulate the end of one end of the rolled finned tube 451 and the U-shaped elbow 452, while the second insulation material layer 64 is used to insulate the end of the other end of the rolled finned tube 451 and the U-shaped elbow 452. This can reduce the heat loss caused by heat diffusion from both ends of the second tube bundle 4.

[0067] In a preferred embodiment of the present invention, a third insulation material layer 65 is provided at the bottom of the second tube bundle 4. Since the bottom of the second tube bundle 4 needs to be supported by the second tube bundle support 44, in order to reduce the transfer of heat from the second tube bundle 4 to the bottom of the second tube bundle support 44, the present invention employs a third insulation material layer 65 at the bottom of the second tube bundle 4. This reduces heat transfer and diffusion to the bottom of the second tube bundle support 44, thereby reducing heat loss and helping to improve the heat exchange effect.

[0068] In a specific implementation of the present invention, the first insulation material layer 62, the second insulation material layer 64, and the third insulation material layer 65 can all be made of insulation materials such as rock wool and glass wool.

[0069] In a preferred embodiment of the present invention, the condensate inlet 41 and the condensate outlet 42 are located on both sides of the same end of the second tube bundle 4, and a water inlet manifold 46 is vertically arranged between the condensate inlet 41 and the input end of the second tube bundle 4, and a water outlet manifold 47 is vertically arranged between the condensate outlet 42 and the output end of the second tube bundle 4. In practical use, the condensate from the process steam in the pharmaceutical plant, after being input through the condensate inlet 41, will first be collected in the water inlet manifold 46 and then enter each heat exchange unit 45; similarly, after the condensate is discharged from each heat exchange unit 45, it will first be collected in the water outlet manifold 47 and then discharged through the condensate outlet 42.

[0070] In a preferred embodiment of the present invention, the condensate inlet 41 is connected to the upper end of the inlet manifold 46, and the lower end of the inlet manifold 46 is provided with a drain outlet 48, which facilitates drainage and liquid discharge when not in use; the condensate outlet 42 is connected to the lower end of the outlet manifold 47, and the upper end of the outlet manifold 47 is provided with a vent outlet 49, which facilitates the discharge of accumulated air in the outlet manifold 47.

[0071] In a preferred embodiment of the present invention, a first lifting lug 40 is fixedly provided on the top of the second tube bundle 4 to facilitate the hoisting operation of the second tube bundle 4.

[0072] In a preferred embodiment of the present invention, in order to better separate the low-temperature exhaust gas after heat exchange, the gas-liquid separator 5 includes an outer frame 51 and a plurality of separation units 52 arranged sequentially along the exhaust gas output direction.

[0073] Each separation unit 52 includes a support rod 521 and a plurality of separation plates 522 mounted on the support rod 521, so as to support each separation plate 522 by means of the support rod 521. An exhaust gas passage 523 is formed between two adjacent separation plates 522 so that low-temperature exhaust gas can pass through the exhaust gas passage 523.

[0074] In one specific embodiment of the present invention, in order to achieve a better water collection effect, the separating plate 522 includes a vertical connecting plate 5221, an inclined plate 5222 and a water collection hook 5223 connected in sequence, wherein the vertical connecting plate 5221 is fixedly assembled and connected to the support rod 521.

[0075] In a preferred embodiment of the present invention, a liquid collection tank 15 is formed by a downward indentation at the inner bottom of the first outer shell 1 near the gas-liquid separator 5. A drain port 16 communicating with the liquid collection tank 15 is provided on the outside of the first outer shell 1. During normal operation, the drain port 16 is normally closed to prevent heated air from escaping from the drain port 16. Because the high-temperature exhaust gas will condense after heat exchange through the first tube bundle 3, and the condensate will fall downwards after gas-liquid separation by the gas-liquid separator 5, forming a liquid collection tank 15 at the bottom of the first outer shell 1 facilitates the collection of the condensate, which is then discharged uniformly from the drain port 16.

[0076] In a preferred embodiment of the present invention, a second lifting lug 17 is fixedly provided on the top of the first outer shell 1 to facilitate hoisting operations using the second lifting lug 17.

[0077] In practical use, the combined heat exchanger 100 of this invention uses high-temperature exhaust gas generated from the pharmaceutical process and condensate from process steam as its heat source, and cold air as its cold source; wherein, the temperature of the high-temperature exhaust gas generated from the pharmaceutical process is around 70°C, and the flow rate of the high-temperature exhaust gas is 10,000 m³ / h. 3 / h; the temperature of the condensate from the process steam is around 90℃, and the flow rate is 6-7t / h; the temperature of the cold air is around 25℃, and the flow rate is 5000m³ / h. 3 / h; After heat exchange, the temperature of the output hot air is greater than 80℃, the temperature of the high-temperature exhaust gas is reduced to below 60℃, and the temperature of the condensate is reduced to below 80℃. By applying this combined heat exchanger 100 to the pharmaceutical process, it is possible to avoid heat energy waste and is beneficial to environmental protection, making it particularly suitable for promotion and use in pharmaceutical plants.

[0078] Please refer to Figures 1 to 16 As shown, a preferred embodiment of the heat exchange method of the combined heat exchanger 100 of the present invention is described above in detail, and will not be repeated here. The heat exchange method includes the following steps:

[0079] The high-temperature exhaust gas generated by the pharmaceutical process is input into the first outer shell 1 through the exhaust gas inlet 11 at one end. The high-temperature exhaust gas passes through the gap between the stainless steel tubes 33 of the first tube bundle 3 and exchanges heat with the outer wall of the stainless steel tubes 33 to realize the waste heat recovery of the high-temperature exhaust gas generated by the pharmaceutical process. This can avoid the waste of heat energy and is beneficial to environmental protection. The low-temperature exhaust gas after heat exchange is sent to the gas-liquid separator 5 for gas-liquid separation. The low-temperature exhaust gas after gas-liquid separation is output through the exhaust gas outlet 12 at the other end of the first outer shell 1. The condensate after gas-liquid separation falls down and collects at the bottom of the first outer shell 1. Specifically, it will collect in the liquid collection tank 15 at the bottom of the first outer shell 1 and then be discharged through the drain port 16.

[0080] The condensate from the process steam is fed into the second tube bundle 4 through the condensate inlet 41. The condensate passes through the rolled finned tubes 451 of the second tube bundle 4 and exchanges heat with the inner wall of the rolled finned tubes 451. The condensate after heat exchange is discharged through the condensate outlet 42 to recover the waste heat of the condensate from the process steam in the pharmaceutical plant.

[0081] The air to be heated is introduced into the first tube bundle 3 through the cold air inlet 231 of the rear shell 23. The air passes through the stainless steel tube 33 in the rear half of the first tube bundle 3 and enters the first rear tube box 13. During this process, the air contacts and exchanges heat with the inner wall of the stainless steel tube 33 in the rear half, thus raising the air temperature. The heated air then enters the stainless steel tube 33 in the front half of the first tube bundle 3 from the first rear tube box 13, and contacts and exchanges heat with the inner wall of the stainless steel tube 33 in the front half, further raising the air temperature. In specific implementation, the high-temperature exhaust gas generated by the pharmaceutical process, after entering the first outer shell 1, will first pass through the front half of the first tube bundle 3 and then through the rear half of the first tube bundle 3. Therefore, the first... The temperature of the rear half of tube bundle 3 is lower than that of the front half of the first tube bundle 3, which allows the air to be further heated. The further heated air enters the front shell 22 through the stainless steel tube 33 in the front half. Then the air passes through the gap between the rolled finned tubes 451 of the second tube bundle 4 and contacts the outer wall of the rolled finned tubes 451 for heat exchange, which raises the temperature of the air again. Since the temperature of the condensate from the process steam is about 90°C, which is higher than the high temperature exhaust gas (about 70°C) produced by the pharmaceutical process, the air can be further heated when passing through the second tube bundle 4. Finally, the hot air is output through the hot air outlet 241 of the second rear tube box 24 and enters the corresponding process pipeline.

[0082] In summary, by adopting the technical solution of the present invention, at least the following beneficial effects are achieved:

[0083] 1. By utilizing the cooling of high-temperature exhaust gas and condensate from process steam generated in pharmaceutical manufacturing, the heat generated during the cooling process of the high-temperature exhaust gas and condensate is transferred to the air through the first and second tube bundles. This heats the air required for drying the pharmaceuticals, which not only reduces the amount of steam and fuel needed to heat the air, but also enables the recovery and reuse of waste heat from the high-temperature exhaust gas and condensate, avoiding heat waste and achieving energy-saving effects; it also reduces pollution to the surrounding environment, which is beneficial to environmental protection.

[0084] 2. Excellent overall heat exchange performance. For heat exchange in the high-temperature exhaust gas section, a bare tube heat exchanger is used, allowing gas to convect on the inner and outer surfaces of the stainless steel bare tube 33, thus achieving heat exchange between the high-temperature exhaust gas and the air. For heat exchange in the condensate section, a U-tube heat exchanger is used. Because the rolled finned tube 451 can disturb the fluid and continuously break the boundary layer, it has a good heat transfer coefficient, enhancing heat exchange performance. Simultaneously, the integrated manifold within the rolled finned tube 451 improves pressure resistance. The combined use of the bare tube heat exchanger and the U-tube heat exchanger enhances heat exchange performance and ensures optimal heat exchange results.

[0085] 3. By integrating the bare tube heat exchanger and the U-tube heat exchanger into one heat exchange device, the waste heat of high-temperature exhaust gas and condensate can be recovered simultaneously. The overall structure is compact, small in size, and has a good sealing effect, which can reduce the overall footprint of the equipment and reduce production costs.

[0086] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A combined heat exchanger, characterized by: The application relates to a pharmaceutical process tail gas heat exchanger, which comprises a first shell, a second shell, a first tube bundle, a second tube bundle and a gas-liquid separator. The first tube bundle is assembled in the first shell; one end of the first shell is provided with a tail gas inlet, and the other end of the first shell is provided with a tail gas outlet; high-temperature tail gas generated in a pharmaceutical process is transported into the first shell through the tail gas inlet, and low-temperature tail gas after separation is discharged through the tail gas outlet; the first shell is provided with a first rear tube box on the side far from the second shell; the gas-liquid separator is arranged in the first shell and located at one end close to the tail gas outlet. The second shell is divided into a front shell and a rear shell by a partition plate. The second tube bundle is assembled in the front shell; the input end of the second tube bundle is connected with a condensate water inlet; the output end of the second tube bundle is connected with a condensate water outlet; condensate water condensed from process steam in a pharmaceutical factory is transported into the second tube bundle through the condensate water inlet, and low-temperature condensate water after heat exchange is output through the condensate water outlet. The rear shell is connected with the rear section of the other side of the first shell and serves as the first front tube box of the first shell; the rear shell is provided with a cold air inlet; the rear shell is communicated with the first rear tube box through the first tube bundle; the front shell is provided with a second rear tube box on the side far from the first shell; the front shell is connected with the front section of the other side of the first shell; the front shell is communicated with the first rear tube box through the first tube bundle.

2. A combined heat exchanger as claimed in claim 1, characterized in that: The first tube bundle comprises first support tube plates fixed on the two sides of the first shell, a first tube bundle support arranged in the first shell and a plurality of stainless steel light pipes arranged on the first tube bundle support; the two ends of the stainless steel light pipes pass through the first support tube plates on the two sides and are expanded and fixed with the first support tube plates.

3. A combined heat exchanger as claimed in claim 1, characterized in that: The second tube bundle comprises second support tube plates fixed on the two ends of the front shell, a second tube bundle support arranged in the front shell and a plurality of heat exchange units arranged from bottom to top on the second tube bundle support; Each heat exchange unit comprises a plurality of rolled finned pipes and a plurality of U-shaped elbows; the rolled finned pipes are arranged along the width direction of the second tube bundle support; one end of the first rolled finned pipe serves as a water inlet and is communicated with the condensate water inlet; one end of the last rolled finned pipe serves as a water outlet and is communicated with the condensate water outlet; the U-shaped elbows are arranged between adjacent two rolled finned pipes.

4. A combined heat exchanger as claimed in claim 3, characterized in that: One end of the front shell is fixed with a first heat preservation box outside the second support tube plate; the first heat preservation box is filled with a first heat preservation material layer; one end of the rolled finned pipe extends into the first heat preservation box; the other end of the front shell is fixed with a second heat preservation box outside the second support tube plate; the second heat preservation box is filled with a second heat preservation material layer; the other end of the rolled finned pipe extends into the second heat preservation box.

5. A combined heat exchanger as claimed in claim 1, characterized in that: The condensate inlet and condensate outlet are located on both sides of the same end of the second tube bundle, and a water inlet collecting pipe is vertically arranged between the condensate inlet and the input end of the second tube bundle, and a water outlet collecting pipe is vertically arranged between the condensate outlet and the output end of the second tube bundle.

6. A combined heat exchanger as claimed in claim 5, characterized in that: The condensate inlet is connected to the upper end of the inlet manifold, and a drain outlet is provided at the lower end of the inlet manifold; the condensate outlet is connected to the lower end of the outlet manifold, and a vent is provided at the upper end of the outlet manifold.

7. A combined heat exchanger as claimed in claim 1, characterized in that: The gas-liquid separator includes an outer frame and several separation units arranged sequentially along the exhaust gas output direction. Each separation unit includes a support rod and several separation plates mounted on the support rod, with an exhaust gas passage formed between two adjacent separation plates.

8. A combined heat exchanger as claimed in claim 1, characterized in that: The bottom of the first outer shell is recessed downward near the gas-liquid separator to form a liquid collection tank, and the outside of the first outer shell is provided with a drain port that communicates with the liquid collection tank.

9. A combined heat exchanger as claimed in claim 3, characterized in that: The bottom of the second tube bundle is provided with a third insulation material layer.

10. A heat exchange method based on the combined heat exchanger according to any one of claims 1-9, characterized in that: The heat exchange method includes the following steps: The high-temperature exhaust gas generated by the pharmaceutical process is introduced into the first outer shell through the exhaust gas inlet at one end. The high-temperature exhaust gas passes through the gap between the stainless steel tubes of the first tube bundle and exchanges heat with the outer wall of the stainless steel tubes. The low-temperature exhaust gas after heat exchange is sent to the gas-liquid separator for gas-liquid separation. The low-temperature exhaust gas after gas-liquid separation is output through the exhaust gas outlet at the other end of the first outer shell. The condensate after gas-liquid separation falls down and collects at the bottom of the inner side of the first outer shell. The condensate from the process steam is fed into the second tube bundle through the condensate inlet. The condensate passes through the rolled finned tubes of the second tube bundle and exchanges heat with the inner wall of the rolled finned tubes. The condensate after heat exchange is discharged through the condensate outlet. The air to be heated is introduced into the first tube bundle through the cold air inlet of the rear shell. The air passes through the stainless steel tubes in the rear half of the first tube bundle and enters the first rear tube box. During this process, the air contacts and exchanges heat with the inner wall of the stainless steel tubes in the rear half, causing the air to heat up. The heated air then enters the stainless steel tubes in the front half of the first tube bundle from the first rear tube box, and contacts and exchanges heat with the inner wall of the stainless steel tubes in the front half, causing the air to heat up further. The further heated air then enters the front shell from the stainless steel tubes in the front half. After that, the air passes through the gaps between the rolled finned tubes of the second tube bundle and contacts and exchanges heat with the outer wall of the rolled finned tubes, causing the air to heat up again to obtain hot air. Finally, the hot air is output through the hot air outlet of the second rear tube box and enters the corresponding process pipeline.

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