Multi-stream intermediate medium coiled tube type heat exchanger

Abstract

The utility model discloses a multi-stream intermediate medium coiled tube type heat exchanger. The heat exchanger comprises a tank body, a heat exchange cavity E1 section and a heat exchange cavity E2 section located below the heat exchange cavity E1 section are arranged in the tank body, and the heat exchange cavity E1 section communicates with the heat exchange cavity E2 section through a shell pass. Multiple strands of feed gas are subjected to heat exchange through an intermediate medium refrigerant to reach the required temperature, and cold energy carried by the main medium I is recovered by using the intermediate medium, so that the medium II and the medium III are cooled or gasified; and the intermediate medium is repeatedly gasified and liquefied in the heat exchanger to transfer energy, the refrigerant is recycled, cold energy in the device is utilized to a great extent, energy is saved, and the equipment cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of LNG cold energy recycling, specifically relates to a multi-stream intermediate medium coiled pipe heat exchanger, can recycle the large amount of cold energy released in the gasification process of LNG. BACKGROUND

[0002] Heat exchanger, also known as heat exchanger, is a kind of equipment for realizing heat transfer, it passes part of the heat of hot fluid to cold fluid. In industrial production, heat exchanger plays a vital role, and is widely used in petroleum, chemical industry, electric power, metallurgy, shipbuilding, machinery, food, pharmaceutical and many other fields. According to the different structure and working principle, heat exchanger can be divided into many types, such as plate heat exchanger, shell and tube heat exchanger, spiral plate heat exchanger, spray heat exchanger and mixed heat exchanger.

[0003] LNG, as a liquid form of natural gas, will release a large amount of cold energy in the gasification process. If not recycled, this part of cold energy will be wasted. By designing and applying LNG cold energy recovery heat exchanger, this part of cold energy can be effectively recycled and converted into other forms of energy or used for other industrial processes, thereby improving the overall energy utilization efficiency. Recycling LNG cold energy can reduce the dependence on traditional energy, thereby reducing energy consumption. At the same time, since the product of LNG combustion is mainly water and carbon dioxide, compared with traditional energy such as coal and oil, its environmental pollution is smaller. Therefore, by recycling LNG cold energy, it can also indirectly reduce the emission of greenhouse gases, which is helpful to environmental protection. The recovery of cold energy plays an important role in reducing process energy consumption and optimizing energy structure, and is needed in many industrial production processes, such as air separation, light hydrocarbon separation, food freezing, etc. Using LNG cold energy for these processes can significantly reduce production costs and improve the economic benefits of enterprises.

[0004] In the traditional multi-stream coiled pipe heat exchanger, due to the existence of multiple working media in the pipe, it may cause cross contamination problem between different media. In addition, with the increase of multi-stream pipes, the leading end of the pipe may vibrate, which may damage the heat exchanger equipment. Further, compared with the prior art, the utility model realizes the transmission of cold energy at a large temperature difference and ensures the safety of equipment operation at the same time. UTILITY MODEL CONTENTS

[0005] In order to solve at least one of the problems existing in the prior art, the utility model provides a multi-stream intermediate medium coiled pipe heat exchanger suitable for LNG cold energy recycling, which recycles the cold energy carried by liquid carbon dioxide and LNG to supply cold for other production links in the corresponding industrial system, realizes the full recycling and utilization of energy and multi-energy complementation.

[0006] To achieve the purpose of the utility model, the utility model provides a kind of multi-stream intermediate medium coiled pipe heat exchanger suitable for LNG cold energy recycling, including main medium I heat exchange module and intermediate cooling distribution module, i.e., tank body is divided into first module and second module, heat exchange cavity E1 section is provided in main medium I heat exchange module, heat exchange cavity E2 section is provided in intermediate cooling distribution module,

[0007] Heat exchange cavity E1 section is provided with main medium I tube bundle, heat exchange cavity E2 section is provided with medium II tube bundle and medium III tube bundle, and main medium I tube bundle is located above medium II tube bundle and medium III tube bundle, medium II inlet, medium III inlet, medium II outlet and medium III outlet are provided on intermediate cooling distribution module, and two ends of medium II tube bundle are communicated with medium II inlet and medium II outlet respectively.

[0008] Further, the main medium I tube bundle, the medium II tube bundle and the medium III tube bundle inside the tank body each include a plurality of heat exchange tubes, and each heat exchange tube is spirally coiled into a cylindrical shape, and the plurality of heat exchange cylinders coiled by the plurality of heat exchange tubes are stacked from top to bottom along the axial direction. The multi-tube coiled heat exchanger designs the tube bundle as three or more heat exchange tubes, and each tube is spirally coiled to form an independent heat exchange cylinder. These heat exchange cylinders are arranged in layers and in order from the inner layer to the outer layer in the radial direction. By using small tube diameters and nesting the plurality of heat exchange tubes in layers in this way, the total heat exchange area can be significantly increased, thereby achieving a heat exchange efficiency comparable to that of large heat exchange tubes. Under the premise of maintaining the same heat exchange effect, this design can reduce the manufacturing cost; otherwise, under the condition of consistent cost, it can achieve higher heat exchange efficiency.

[0009] The coiled pipe type increases the heat exchange area, and the heat exchange efficiency can be increased by 13.5% under the condition of equivalent equipment cost.

[0010] Further, the tank body is provided with an intermediate cooling medium optimization condensing drainage plate for draining the refrigerant after heat exchange in the heat exchange cavity E1 section to the heat exchange cavity E2 section.

[0011] Further, the intermediate cooling medium optimization condensing drainage plate is used to distribute the flow direction of the refrigerant condensed by the medium 1 heat exchange module to the intermediate cooling distribution module, the intermediate cooling medium optimization condensing drainage plate separates the first module and the second module in the tank body, and is inclined at an angle of 30°, so as to drain the refrigerant after heat exchange in the heat exchange cavity E1 section to the inlet of the medium II tube bundle.

[0012] Further, the refrigerant includes but is not limited to any one of freon refrigerant and light hydrocarbon refrigerant.

[0013] Further, the freon refrigerant includes, but is not limited to, any one of R23, R507, R410a.

[0014] Further, the light hydrocarbon refrigerant includes, but is not limited to, any one of ethane and propane.

[0015] Further, the primary medium I includes, but is not limited to, any one of LNG and liquid carbon dioxide.

[0016] Further, the medium II includes, but is not limited to, gaseous carbon dioxide.

[0017] Further, the medium III includes, but is not limited to, liquid water.

[0018] Further, the shell is provided with a pressure indicator for monitoring the pressure in the shell.

[0019] Further, the shell is provided with a safety valve group.

[0020] Further, the tank body is provided with an end plate, and the primary medium I tube bundle, the medium II tube bundle and the medium III tube bundle are fixed on the end plate.

[0021] Further, an anti-collision plate is further included, and the anti-collision plate is located in the tank body and is arranged between the end plate and the inner wall of the tank body, so that the shell-side refrigerant cannot contact the inner wall of the tank body, and the tank body is protected from being washed and corroded by the refrigerant in the shell.

[0022] The use method of the multi-strand flow around pipe type heat exchanger, comprising:

[0023] The primary medium I, the medium II and the medium III enter the primary medium I tube bundle, the medium II tube bundle and the medium III tube bundle from the primary medium I inlet, the medium II inlet and the medium III inlet respectively;

[0024] The refrigerant exchanges heat with the primary medium I in the heat exchange cavity E1;

[0025] The heat exchanged tube-side heat exchange medium primary medium I, medium II and medium III flow out from the medium II outlet, the medium II outlet and the medium III outlet respectively, the refrigerant is liquefied after being exchanged with the primary medium I, and then falls under the action of gravity, enters the heat exchange cavity E2 and exchanges heat with the medium II and the medium III, and the refrigerant is gasified after exchanging heat with the medium II and the medium III in the heat exchange cavity E2, and then rises to the heat exchange cavity E1 section.

[0026] Compared with the prior art and the present situation, the utility model has at least the following beneficial effects:

[0027] 1. Improve energy utilization. The multi-strand flow intermediate medium around pipe type heat exchanger recovers the cold energy released by LNG gasification, realizes the full recovery and utilization of cold energy.

[0028] 2. Good energy saving and consumption reducing benefit. The multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model can be used in parallel at both ends of the main medium I gasification system, the cold energy carried by the main medium I is transferred by the heat exchanger, and the cold energy is used for cooling the raw material gas and the chilled water, so that the process operation energy consumption and the refrigerating unit energy consumption can be reduced. Taking the LNG cold energy process with a recovery flow of 10.8t / h, a temperature of-27 DEG C and a pressure of 1.6MPa as an example, the cold energy carried by the multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model is recovered to cool the raw material gas and the chilled water, and the annual power saving amount can reach 2.354x10 6 kWh.

[0029] 3. Good safety performance, convenient maintenance and management. The multi-flow coiled pipe intermediate medium heat exchanger is mature in principle, and the related equipment and facilities have rich practical application experience in other cold energy utilization fields; the liquefied carbon dioxide cold energy recovery and utilization integrated process device with the same principle as the device can be used in parallel at both ends of the carbon dioxide gasification system in the general production process, the use of the process device has little influence on the original carbon dioxide gasification process and refrigeration process, and the integrated device can be cut off under special conditions, and the system has high flexibility.

[0030] 4. High heat exchange efficiency. In the utility model, the circulating refrigerant multi-flow heat exchange and the spiral coiled pipe bundle increase the heat exchange area, the multi-flow raw material gas is simultaneously heat exchanged in the device, and the heat exchange efficiency is also improved compared with the conventional heat exchanger design.

[0031] 5. The utility model is especially suitable for the occasions that need to simultaneously process multiple working media, transfer a large amount of heat under a large temperature difference and the operating pressure of the medium in the pipe is high. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A cross-sectional view of a multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model embodiment.

[0033] Figure 2 A front view of a multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model embodiment.

[0034] Figure 3 A side view of a multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model embodiment.

[0035] Figure 4 A transverse overhead view of a multi-flow intermediate medium coiled pipe heat exchanger provided by the utility model embodiment.

[0036] In the figure, 1 is a refrigerant inlet, 2 is a feed baffle, 3 is a main medium I inlet, 4 is a tank body, 5 is a medium II gasification tube bundle, 6 is a main medium I outlet, 7 is an intermediate cooling medium optimized condensing guide plate, 8 is a shell side, 9 is a gaseous medium II inlet, 10 is a medium III inlet, 11 is a medium II outlet, 12 is a medium III outlet, 13 is a medium II tube bundle, 14 is a medium III tube bundle, 15 is a support, 16 is a refrigerant outlet, 17 is a pressure indicator, 18 is a safety valve group, 19 is a differential pressure liquid level transmitter, 20 is a liquid collection package, 21 is a blowdown port, 22 is an end plate, and 23 is a fender. DETAILED DESCRIPTION

[0037] In order to better understand the present application, the present application will be further described below in conjunction with the drawings and examples, but the scope of protection required by the present application is not limited to the scope of the examples.

[0038] The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in one or more embodiments of the present specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "and / or," as used in one or more embodiments of the present specification, are used to mean any one of the items in the list, or any combination of items in the list with one another.

[0039] In addition, in the present application, the description such as "first", "second" and the like is only for the purpose of description, and is not intended to specifically indicate the order or sequence, nor is it intended to limit the present application. It is merely for the purpose of distinguishing the components or operations described by the same technical terms, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implying the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

[0040] Please refer to Figure 1 The multi-stream intermediate medium heat exchanger provided by the present application comprises a support 15 and a tank body 4 arranged on the support 15. The tank body 4 has a cylinder diameter of 1.7 m and a cylinder height of 8.5 m. The overall shape of the heat exchanger is 10 m high. It can be understood that in other embodiments, the size of the tank body 4 can be other numerical values according to needs.

[0041] The tank body 4 comprises a first module and a second module separated by the intermediate medium optimized condensing drainage plate 7, the heat exchange cavity E1 section is arranged in the first module, and the heat exchange cavity E2 section is arranged in the second module. The heat exchange cavity E1 section and the heat exchange cavity E2 section both comprise a shell side 8, that is, the heat exchange cavity E1 section and the heat exchange cavity E2 section are communicated through the shell side 8. The intermediate medium which exchanges heat with the main medium I is introduced into the shell side 8; the main medium I tube bundle 5 is arranged in the heat exchange cavity E1 section, the medium II tube bundle 13 and the medium III tube bundle 14 are arranged in the heat exchange cavity E2, and the main medium I tube bundle 5 is located above the medium II tube bundle 13 and the medium III tube bundle 14; the medium II tube bundle 13 and the medium III tube bundle 14 are parallelly coiled in the heat exchange cavity E2; the heat exchange cavity E2 section in the tank body 4 is provided with a collecting box 20 which is communicated with the shell side 8 and is used for storing impurities in the refrigerant due to pipeline aging or other reasons; the main medium I inlet 3 and the main medium I outlet 6 are arranged on the tank body 4 and correspond to the position of the heat exchange cavity E1 section, the main medium I inlet 3 is communicated with the main medium I tube bundle 5 so as to introduce the main medium I into the main medium I tube bundle 5.

[0042] The top of the tank body 4 is provided with a refrigerant inlet 1, and the bottom is provided with a refrigerant outlet 16, and the refrigerant inlet 1 and the refrigerant outlet 16 are both communicated with the shell side 8.

[0043] The shell side 8 is filled with refrigerant, the main medium I is introduced into the main medium I tube bundle 5 located in the heat exchange cavity E1 section, the refrigerant exchanges heat with the main medium I, the temperature of the main medium I is increased after heat exchange and is discharged through the main medium I outlet 6. The refrigerant which is liquefied after heat exchange with the main medium I drops by gravity, is drained to the heat exchange cavity E2 section by the intermediate cooling medium optimized condensing drainage plate 7, exchanges heat with the medium II and the medium III in the heat exchange cavity E2 section, is gasified after heat exchange with the medium II and the medium III, and then rises to the heat exchange cavity E1 section.

[0044] The medium II tube bundle 13 and the medium III tube bundle 14 are arranged in the heat exchange cavity E2 section, the medium II outlet 11, the medium III outlet 12, the medium II inlet 9 and the medium III inlet 10 are arranged on the tank body 4 and correspond to the position of the heat exchange cavity E2 section, the medium II inlet 9 and the medium II outlet 11 are respectively communicated with the inlet and the outlet of the medium II tube bundle 13, the medium III inlet 10 and the medium III outlet 12 are respectively communicated with the inlet and the outlet of the medium III tube bundle 14, the medium II enters the medium II tube bundle 13 through the medium II inlet 11, exchanges heat with the refrigerant which is liquefied after heat exchange with the main medium I and drops by gravity, the medium II after heat exchange is discharged from the medium II outlet 11, the medium III enters the medium III tube bundle 14 through the medium III inlet 12, exchanges heat with the refrigerant which is liquefied after heat exchange with the main medium I, and the medium III after heat exchange is discharged from the medium III outlet 12.

[0045] The refrigerant includes R23, R507, R410a and other freon refrigerants, or various light hydrocarbon refrigerants such as ethane and propane and mixtures thereof.

[0046] In some embodiments of the utility model, the outer wall of the shell side 8 is provided with a pressure indicator 17, the pressure of the shell side 8 is monitored through the pressure indicator 17, so that the refrigerant leakage, CO2 or medium III in the shell can be warned in time.

[0047] In some embodiments of the utility model, the outer wall of the shell side 8 is provided with a safety valve group 18. When stopping for a long time, the temperature of the intermediate medium refrigerant in the shell side 8 rises, which causes the pressure to rise and exceed the pressure bearing capacity of the shell side 8. At this time, the overpressure relief can be carried out through the safety valve group 18. In addition, when the refrigerant or CO2 leaks in the accident condition, the pressure exceeding the pressure bearing capacity of the shell side 8 can also be discharged through the safety valve group 18, so that the safety performance of the device can be improved.

[0048] In some embodiments of the utility model, the end plate 22 is arranged in the shell side 8, the main medium I tube bundle 5, the medium II tube bundle 13 and the medium III tube bundle 14 are all fixed on the end plate 22, and the main medium I tube bundle 5, the medium II tube bundle 13 and the medium III tube bundle 14 can be fixed in the shell side 8 through the end plate 22.

[0049] In some embodiments of the utility model, the bottom of the collecting tank 20 is provided with a blowdown opening 21, and the impurities such as iron filings brought into the refrigerant due to pipeline aging or other reasons are discharged through the blowdown opening 21.

[0050] In some embodiments of the utility model, the differential pressure liquid level transmitter 19 is further arranged on the collecting tank 20. The pressure conditions in the collecting tank 20 and the shell side 8 are monitored according to the liquid level of the refrigerant in the collecting tank 20.

[0051] In some embodiments of the utility model, the anti-collision plate 23 is further arranged in the tank body 4, which is used for preventing the refrigerant in the shell side from contacting the inner wall of the tank body 4.

[0052] In some embodiments of the utility model, in order to facilitate understanding, taking the refrigerant as R507, the main medium I as LNG, the flow as 10.8t / h, the temperature as-90 DEG C, the pressure as 1.6MPa, the medium II as gaseous carbon dioxide, the flow as 21.2t / h, the temperature as 40 DEG C, the pressure as 0.14MPa, the medium III as liquid water, the flow as 90t / h, the temperature as 5.7 DEG C, and the pressure as 0.2MPa.

[0053] Gaseous refrigerant R507 enters the heat exchange cavity E1 through the refrigerant inlet 1; LNG at-90℃ enters the primary medium I tube bundle 5 in the heat exchange cavity E1 section and exchanges heat with the gaseous refrigerant R507 in the shell side 8, which has a flow rate of 20.4t / h, a temperature of 1℃ and a pressure of 0.6MPa, for the first time; the LNG (primary medium I) after heat exchange is gasified into gaseous carbon dioxide and the temperature is increased to-70℃; the gaseous refrigerant R507 absorbs cold energy and is liquefied, and the temperature of the liquid refrigerant R507 is reduced to-3.1℃; the liquid refrigerant R507 then falls under the action of gravity and flows to the inlet end of the medium II tube bundle 13 in the heat exchange cavity E2 section through the intermediate cooling medium optimized condensation drainage plate 7 between the first module and the second module, and a small part flows to the medium III tube bundle 14 in the heat exchange cavity E2 section, and exchanges heat with gaseous CO2 (medium II) having a flow rate of 21.2t / h, a temperature of 40℃ and a pressure of 0.14MPa and water (medium III) having a flow rate of 90t / h, a temperature of 5.7℃ and a pressure of 0.2MPa for the second time; the liquid refrigerant R507 is gasified and the temperature is increased to 1℃, and then rises naturally under the action of gravity to return to the heat exchange cavity E1 section to perform cyclic heat exchange work; the gaseous carbon dioxide in the medium II tube bundle 13 is cooled to 40℃ after heat exchange; and the liquid water in the medium III tube bundle 14 is cooled to 2℃ after heat exchange.

[0054] In the heat exchange process of the foregoing embodiment of the utility model, the upper heat exchange is the heat exchange between LNG and gaseous refrigerant R507, and the heat exchange efficiency is 0.75; the lower heat exchange is the heat exchange between liquid refrigerant R507 and gaseous carbon dioxide and the heat exchange between liquid refrigerant R507 and liquid water, and the heat exchange efficiencies are 0.65 and 0.75 respectively; according to the total heat exchange area 385m 2 The equipment cost estimation shows that the heat exchanger investment cost is about 378,000 yuan; compared with the heat exchanger with the same equipment cost, the heat exchange efficiency is increased by 13.5%.

[0055] The pipe-wound intermediate medium heat exchanger provided by the foregoing embodiment of the utility model is characterized in that the refrigerant R507 runs through the shell side 8, and the carbon dioxide and water run through the tube side.

[0056] The foregoing embodiments of the utility model are merely examples for clearly illustrating the utility model and are not intended to limit the implementation manners of the utility model. Other different forms of changes or variations can be made by those skilled in the art on the basis of the foregoing description. Here, it is not necessary and impossible to exhaust all the implementation manners. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model shall be included in the protection scope of the utility model claims.

Claims

1. A multi-stream, intermediate medium, spiral wound heat exchanger, characterized in that, The tank body (4) is provided with a heat exchange cavity E1 section and a heat exchange cavity E2 section below the heat exchange cavity E1 section, and the heat exchange cavity E1 section and the heat exchange cavity E2 section are communicated through a shell side (8). The shell side (8) can contain refrigerant, the heat exchange cavity E1 section is provided with a main medium I tube bundle (5), the heat exchange cavity E2 section is provided with a medium II tube bundle (13) and a medium III tube bundle (14), and the main medium I tube bundle (5) is located above the medium II tube bundle (13), and the gaseous medium II tube bundle (13) is parallelly coiled above the medium III tube bundle (14).

2. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The main medium I inlet (3) and the main medium I outlet (6) are arranged on the tank body (4) and correspond to the position of the heat exchange cavity E1 section, and the two ends of the main medium I tube bundle (5) are communicated with the main medium I inlet (3) and the main medium I outlet (6) respectively. The medium II outlet (11), the medium III outlet (12), the medium II inlet (9) and the medium III inlet (10) are arranged on the tank body (4) and correspond to the position of the heat exchange cavity E3 section, the two ends of the medium II tube bundle (13) are communicated with the medium II outlet (11) and the medium II inlet (9) respectively, and the two ends of the medium III tube bundle (14) are communicated with the medium III outlet (12) and the medium III inlet (10) respectively.

3. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The main medium I tube bundle (5), the medium II tube bundle (13) and the medium III tube bundle (14) in the tank body (4) each include a plurality of heat exchange tubes, and each heat exchange tube is spirally coiled into a cylindrical shape, and a plurality of heat exchange cylinders coiled by the plurality of heat exchange tubes are stacked from top to bottom along the axial direction.

4. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The tank body (4) is further provided with a collision prevention plate (23) for preventing the refrigerant in the shell side from contacting the inner wall of the tank body (4).

5. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The first module is provided with a pressure indicator (17) for monitoring the pressure of the tank body (4).

6. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The tank body (4) is provided with a safety valve group (18).

7. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 1, wherein, The tank body (4) is provided with an intermediate cooling medium optimized condensing drainage plate (7) for draining the refrigerant after heat exchange in the heat exchange cavity E1 section to the heat exchange cavity E2 section.

8. A multi-stream intermediate medium heat exchanger as claimed in claim 1, wherein, The tank body (4) is provided with an end plate (22), and the main medium I tube bundle (5), the medium II tube bundle (13) and the medium III tube bundle (14) are fixed on the end plate (22).

9. A multi-pass, intermediate medium spiral wound heat exchanger according to any one of claims 1 to 8, wherein, The heat exchange cavity E2 is provided with a collecting box (20), and the bottom of the collecting box (20) is provided with a blowdown port (21).

10. A multi-stream, intermediate medium, spiral wound heat exchanger according to claim 9, wherein, The collecting box (20) is provided with a differential pressure liquid level transmitter (19).

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