A refrigerator suitable for VOCs tail gas treatment

Abstract

The present application discloses a freezer suitable for VOCs tail gas treatment, which is a U-shaped tube vertical structure as a whole, including a heat exchanger shell and a heat exchanger tube box, and a tube sheet is set between the two; a U-shaped heat exchange tube bundle is set in the heat exchanger shell, and the U-shaped heat exchange tube bundle is composed of a plurality of U-shaped tubes, and the two ends of the U-shaped tubes are fixedly set on the tube sheet and communicate with the internal space of the heat exchanger tube box; the heat exchanger shell, the heat exchanger tube box and the U-shaped heat exchange tube bundle are divided into left and right sides by a layered plate, and the lower ends of the left and right sides of the heat exchanger tube box are respectively provided with a refrigerant inlet and a refrigerant outlet, and the upper ends of the left and right sides of the heat exchanger shell are respectively provided with a VOCs tail gas inlet and a VOCs tail gas outlet near the tube sheet. The device of the present application can avoid the VOCs component from being enriched in large quantities on the equipment, causing the freezer to be frozen in a short time, and there is no dead corner of liquid accumulation on the inner wall of the equipment shell. When freezing, it can avoid the accumulation of liquid and the freezing expansion, which causes the equipment to crack and affect the life of the equipment.

Description

Technical Field

[0001] The present application discloses a refrigerator suitable for treating VOCs tail gas. Background Art

[0002] At present, in the field of VOCs treatment, condensation is an effective treatment method for VOCs tail gas with high concentration and low freezing point, but in the actual production process, its operation status and duration are often restricted by the freezer. The main problems include the following: 1. VOCs process gas usually passes through the inside of the freezer pipe. Because VOCs freeze and adhere to the inner wall of the pipe, the heat exchange pipe can be blocked in a short time, resulting in increased heat exchanger pressure, hindering gas flow, causing equipment shutdown, and having a great impact on the operation of the device; 2. Due to the extremely low temperature characteristics of the refrigerant, the conventional horizontal heat exchanger has uneven distribution of refrigerant fluid and inconsistent cold spot distribution inside the freezer, resulting in large deviations in the degree of crystallization in various parts of the freezer, and the corresponding heat load is also inconsistent, affecting the operation of the equipment; 3. Conventional heat exchangers are equipped with support plates or baffles, etc., and there are a large number of low points and welding points. There will be liquid accumulation when the equipment is running, resulting in cracks in the welds and baffles when freezing, causing safety hazards. Summary of the invention

[0003] The purpose of this application is to provide a freezer suitable for VOCs tail gas treatment in response to the process defects of existing freezers. The device structure of this application is particularly suitable for the freezing treatment of VOCs tail gas with a low freezing point. It adopts a suitable heat exchanger structure with a unique internal design to perform freezing and recovery treatment on the VOCs components of the tail gas. It is suitable for related enterprises with high-concentration VOCs tail gas emissions with a low freezing point.

[0004] The freezer suitable for VOCs tail gas treatment is characterized in that it is a U-shaped tube vertical structure as a whole, including a heat exchanger shell and a heat exchanger tube box arranged on the top of the heat exchanger shell, and a horizontal tube sheet is arranged between the two; a U-shaped heat exchange tube bundle is arranged in the heat exchanger shell, and the U-shaped heat exchange tube bundle is composed of a number of U-shaped tubes with different bending radii, and the two ends of the U-shaped tubes are fixedly arranged on the tube sheet and are communicated with the internal space of the heat exchanger tube box; the heat exchanger shell, the heat exchanger tube box and the U-shaped heat exchange tube bundle are divided into left and right sides by a layered plate, and the lower ends of the left and right sides of the heat exchanger tube box are respectively provided with a refrigerant inlet and a refrigerant outlet, and the upper ends of the left and right sides of the heat exchanger shell are respectively provided with a VOCs tail gas inlet and a VOCs tail gas outlet near the tube sheet.

[0005] The refrigerator suitable for VOCs tail gas treatment is characterized in that the left port of each U-shaped tube in all the U-shaped tubes in the U-shaped heat exchange tube bundle corresponds to a connecting pipe cap, and the refrigerant introduced into the left side space of the heat exchanger tube box from the refrigerant inlet accumulates on the tube plate. When the accumulated liquid layer covers the pipe cap, the refrigerant liquid is evenly distributed into the U-shaped heat exchange tube bundle.

[0006] The freezer suitable for VOCs tail gas treatment is characterized in that the outlet of the refrigerant inlet is located on the left side of the heat exchanger tube box and is provided with a downward elbow or baffle to make the liquid flow downward.

[0007] The freezer suitable for VOCs tail gas treatment is characterized in that among all the U-shaped tubes in the U-shaped heat exchange tube bundle, a pipeline internal is arranged in the left end of each U-shaped tube.

[0008] The freezer suitable for VOCs tail gas treatment is characterized in that all the U-shaped tubes of the U-shaped heat exchange tube bundle are fixed together for support by fixing parts on the left side and the right side respectively, and the fixing parts are fixed tube clamps.

[0009] The freezer suitable for VOCs tail gas treatment is characterized in that a heating device is arranged on the outside of the heat exchanger shell, and the heating device adopts a heating coil.

[0010] The freezer suitable for VOCs tail gas treatment is characterized in that a drain port is provided at the bottom center of the heat exchanger shell, and a crystal baffle is provided at the internal entrance of the drain port to prevent drain blockage.

[0011] Compared with the prior art, the beneficial effects achieved by this application are:

[0012] 1. In the freezer device of the present application, the VOCs process exhaust gas passes through the shell side of the heat exchanger, and the refrigerant enters the tube side of the heat exchanger. Therefore, under the same pipe layout conditions, the passage area of ​​the VOCs process gas is more than 5 times that of the conventional heat exchanger, reducing the probability of freezer blockage.

[0013] 2. The freezer of the present application adopts a vertical structure, and the outlet of the refrigerant inlet is located on the left side of the heat exchanger tube box and is provided with a downward elbow or baffle to make the liquid flow downward. Secondly, in all the U-shaped tubes of the U-shaped heat exchange tube bundle, the left port of each U-shaped tube corresponds to a connecting pipe cap, so that the incoming refrigerant is evenly distributed into the heat exchanger pipeline, ensuring that the radial temperature distribution in each heat exchange tube in the freezer is uniform, reducing the possibility of local blockage.

[0014] 3. This freezer adopts a vertical structure, eliminating baffles and support plates. Fixed pipe clamps and other fixings are used as support between the heat exchange tubes. While ensuring the strength of the equipment, the low points and corresponding welds in the equipment are avoided. The lowest point where the process gas passes is the drain port of the heat exchanger. Therefore, this equipment can effectively avoid equipment cracking caused by crystal expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the freezer for this application;

[0016] In the figure: 1. pipe cap; 2. refrigerant inlet; 3. VOCs exhaust gas inlet; 4. U-shaped heat exchange tube bundle; 5. fixings; 6. layered plate; 7. heating coil; 8. drain port; 9. heat exchanger tube box; 10. refrigerant inlet; 11. VOCs exhaust gas inlet; 12. crystallization baffle; 13. heat exchanger shell; 14. pipeline internals. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0018] Example: Control Figure 1

[0019] VOCs tail gas can be isoprene tail gas, and the refrigerant can be liquid nitrogen.

[0020] A freezer suitable for VOCs tail gas treatment, which is a U-tube vertical structure as a whole, including a heat exchanger shell 13 and a heat exchanger tube box 9 arranged on the top of the heat exchanger shell 13, and a horizontal tube sheet is arranged between the two; a U-shaped heat exchange tube bundle 4 is arranged in the heat exchanger shell 13, and the U-shaped heat exchange tube bundle 4 is composed of a plurality of U-shaped tubes with different bending radii, and both ends of the U-shaped tubes are fixedly arranged on the tube sheet and are communicated with the internal space of the heat exchanger tube box 9; the heat exchanger shell 13, the heat exchanger tube box 9 and the U-shaped heat exchange tube bundle 4 are divided into left and right sides by a layered plate 6, and a refrigerant inlet 2 and a refrigerant outlet 10 are respectively arranged at the lower ends of the left and right sides of the heat exchanger tube box 9, and a VOCs tail gas inlet 3 and a VOCs tail gas outlet 11 are respectively arranged at the upper ends of the left and right sides of the heat exchanger shell 13 near the tube sheet.

[0021] Furthermore, the layered plate 6 symmetrically divides the upper portion of the heat exchanger shell 13, the heat exchanger tube box 9 and the U-shaped heat exchange tube bundle 4 into left and right sides. Figure 1 In the embodiment, the layered plate 6 is divided into two parts, the upper and lower parts, which are fixedly arranged on the upper and lower sides of the tube sheet. The upper end of the layered plate 6 of the upper part is fixedly arranged in the middle of the top inner wall of the heat exchanger tube box 9, and the lower end of the layered plate 6 of the lower part is suspended in the lower end of the heat exchanger shell 13.

[0022] Furthermore, all the U-shaped tubes of the U-shaped heat exchange tube bundle 4 are fixed together for support by using fixing members 5 on the left sides and on the right sides respectively, and the fixing members 5 are fixed tube clamps.

[0023] Comparison Figure 1 In the embodiment, the outlet of the refrigerant inlet 2 is located in the left side of the heat exchanger tube box 9 and is provided with a downward elbow or baffle to make the liquid flow downward. In all the U-shaped tubes of the U-shaped heat exchange tube bundle 4, the left port of each U-shaped tube corresponds to the connection cap 1. Liquid nitrogen enters the heat exchanger tube box 9 through the refrigerant inlet 2. The refrigerant inlet 2 is provided with an elbow or baffle to ensure that the liquid nitrogen first flows downward to the tube sheet. The liquid nitrogen level on the tube sheet gradually rises until it reaches the tube cap 1. The liquid nitrogen enters the U-shaped heat exchange tube bundle 4 through the tube cap 1. This arrangement can effectively ensure that the liquid nitrogen is evenly distributed to each U-shaped tube of the U-shaped heat exchange tube bundle 4 to prevent the generation of local cold spots. After the liquid nitrogen enters the U-shaped heat exchange tube bundle 4, it exchanges heat with the VOCs exhaust gas through the heat exchange tube wall.

[0024] Furthermore, in all the U-shaped tubes of the U-shaped heat exchange tube bundle 4, a pipe internal 14 is provided in the left end of each U-shaped tube, which can prolong the time that the liquid nitrogen stays in the U-shaped tube, and can effectively prevent the liquid nitrogen from passing through the heat exchange tube and accumulating at the bottom of the freezer (that is, to prevent the supercooled liquid nitrogen from flowing down quickly to the bottom of the U-shaped tube to form an aggregate), so that the freezer produces a local cold spot and increases the operating resistance. After the liquid nitrogen exchanges heat with the VOCs tail gas, it is gasified, and the gasified low-temperature nitrogen flows from the right port of the U-shaped tube into the right space of the heat exchanger tube box 9, and then passes through the downstream equipment through the refrigerant connection port 10.

[0025] At the same time, the VOCs tail gas enters the heat exchanger shell 13 through the VOCs tail gas inlet 3. A layered plate 6 is arranged in the heat exchanger shell 13, so that the VOCs tail gas flows along the U-shaped direction of the U-shaped tube and exchanges heat with liquid nitrogen. Under the action of liquid nitrogen, the temperature of the organic components in the VOCs tail gas is reduced to below the freezing point and adsorbed on the U-shaped tube. The VOCs process tail gas passes through the shell side of the heat exchanger, and the refrigerant enters the tube side of the heat exchanger. Under the same pipe layout conditions, the passing area of ​​the VOCs process gas is more than 5 times that of the conventional heat exchanger, reducing the probability of freezer blockage. At the same time, the freezer of the present application adopts a vertical structure, and the baffle and support plate are cancelled. Fixed pipe clamps and other fixings are used as support between the heat exchange tubes. While ensuring the strength of the equipment, the existence of low points and corresponding welds in the equipment is avoided. The lowest point through which the process gas passes is the drain port of the heat exchanger. Therefore, this equipment can effectively avoid equipment cracking caused by crystal expansion. The exhaust gas after refrigeration purification is sent to the downstream equipment through the VOCs exhaust gas inlet 11, wherein a wire mesh baffle can be set at the VOCs exhaust gas inlet 11 to intercept the entrained crystalline or liquid VOCs particles.

[0026] Furthermore, in the freezer structure of the present application, a heating device is provided on the outside of the heat exchanger housing 13, and the heating device adopts a heating coil 7. Figure 1 In the embodiment, the heating coil 7 is wound around the outside of the heat exchanger shell 13. A drain port 8 is provided at the bottom center of the heat exchanger shell 13, and a crystallization baffle 12 is provided at the inner entrance of the drain port 8 to prevent the drain from being blocked. The crystallization baffle 12 can be set to a three-dimensional cone. When the freezer structure is in operation or freezing, the VOCs crystals enriched on the U-shaped heat exchange tube bundle 4 and the VOCs crystals collected at the bottom of the freezer can be effectively prevented from being blocked at the drain port 8 by the crystallization baffle. At the same time, the heat exchanger is provided with a heating coil 7, and heating by the heating coil 7 can accelerate the dissolution of the crystals, thereby ensuring the long-term operation of the freezer.

[0027] The device structure of the present application has the following advantages over conventional freezers:

[0028] 1. It can effectively prevent the VOCs components from being accumulated in large quantities on the equipment, causing the freezer to freeze in a short time and the pressure to rise. 2. The inner wall of the equipment shell has no dead corners for liquid accumulation, which can effectively prevent the accumulation of liquid during freezing, causing freezing and expansion, resulting in cracking of the equipment and affecting the life of the equipment. 3. Heating and thawing is more convenient and quick.

[0029] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as being limited to the specific forms described in the embodiments.

Claims

1. A chiller suitable for VOCs tail gas treatment, Features The overall structure is a U-shaped tube vertical structure, comprising a heat exchanger shell (13) and a heat exchanger tube box (9) arranged on the top of the heat exchanger shell (13), and a horizontal tube sheet is arranged between the two. A U-shaped heat exchange tube bundle (4) is arranged in the heat exchanger shell (13), and the U-shaped heat exchange tube bundle (4) is composed of a plurality of U-shaped tubes with different bending radii, and both ends of the U-shaped tubes are fixedly arranged on the tube sheet and communicate with the internal space of the heat exchanger tube box (9); the heat exchanger shell (13), the heat exchanger tube box (9) and the U-shaped heat exchange tube bundle (4) are divided into left and right sides by a layered plate (6), and the lower ends of the left and right sides of the heat exchanger tube box (9) are respectively provided with a refrigerant inlet (2) and a refrigerant outlet (10), and the upper ends of the left and right sides of the heat exchanger shell (13) are respectively provided with a VOCs tail gas inlet (3) and a VOCs tail gas outlet (11) near the tube sheet; The refrigerant is liquid nitrogen; In all the U-shaped tubes of the U-shaped heat exchange tube bundle (4), the left port of each U-shaped tube corresponds to a connection pipe cap (1), and the refrigerant introduced into the left space of the heat exchanger tube box (9) through the refrigerant inlet (2) accumulates on the tube sheet. When the accumulated liquid layer covers the pipe cap (1), the refrigerant liquid is evenly distributed into the U-shaped heat exchange tube bundle (4); The outlet of the refrigerant inlet (2) is located inside the left side of the heat exchanger tube box (9) and is provided with a downward elbow or baffle to allow the liquid to flow downward; In all the U-shaped tubes of the U-shaped heat exchange tube bundle (4), a pipe internal part (14) is arranged in the left end of each U-shaped tube; All the U-shaped tubes of the U-shaped heat exchange tube bundle (4) are fixed together and supported on the left and right sides by fixing members (5), and the fixing members (5) are fixed tube clamps.

2. A refrigerator suitable for VOCs tail gas treatment as claimed in claim 1, Features A heating device is provided on the outside of the heat exchanger shell (13), and the heating device adopts a heating coil (7).

3. A refrigerator suitable for VOCs tail gas treatment as claimed in claim 1, Features A liquid drain port (8) is provided at the bottom center of the heat exchanger shell (13), and a crystal baffle (12) is provided at the inner entrance of the liquid drain port (8) to prevent liquid drain blockage.

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