A two-phase flow dispenser

Abstract

The application discloses a two-phase flow distributor, which comprises a distributor body, an inlet pipe arranged at the top of the distributor body, a scouring sleeve arranged at the bottom end of the inlet pipe, a first outlet hole arranged on the inlet pipe, a second outlet hole arranged on the scouring sleeve, a primary orifice plate arranged below the scouring sleeve, a plurality of distribution heads arranged on the primary orifice plate, a top inlet, a bottom outlet and a side inlet arranged on the distribution head, a secondary tube plate arranged below the primary orifice plate, a plurality of heat exchange tubes arranged on the secondary tube plate, a fluid inlet arranged on the heat exchange tube, and the height of the fluid inlet being equal to or higher than the height of the upper surface of the secondary tube plate, and the heat exchange tube being arranged in a staggered mode with the distribution head. The two-phase flow distributor adopts a multi-stage and pressure-drop-free distribution mode, can make the two-phase flow distribution more uniform, improve the heat exchange performance of the heat exchanger, reduce the possibility of frost formation of the heat exchanger, effectively prolong the defrosting cycle of the heat exchanger, and reduce the system operation energy consumption.

Description

Technical Field

[0001] This invention relates to the field of fluid distribution technology, and more particularly to a two-phase flow distributor. Background Technology

[0002] In a tubular evaporator, after being depressurized by a throttling valve, the refrigerant typically becomes a two-phase flow. How evenly the two-phase refrigerant is distributed to each heat exchanger tube is crucial for improving the heat exchanger's efficiency. Currently, the conventional approach is to use anti-impact plates to address uneven flow distribution. However, conventional anti-impact plate designs are ineffective when there are many heat exchangers and large flow fluctuations. This leads to excessive refrigerant distribution in some heat exchanger tubes, resulting in a consistently high cold-side temperature from inlet to outlet, and even the possibility of incomplete evaporation. Conversely, insufficient refrigerant distribution can cause overheating in some tubes. This situation not only degrades evaporator performance but also leads to ice blockage in the heat exchanger, directly impacting the normal operation of the heat exchanger system.

[0003] When this distribution method is applied to heat exchangers using the newly emerging liquid nitrogen condensation technology for volatile organic compound (VOC) exhaust gases, rapid frost blockage occurs on the hot side (i.e., the VOC exhaust gas side) of the liquid nitrogen heat exchanger. On the cold side (the liquid nitrogen side), where the refrigerant is located, some heat exchange tubes will have excessively low outlet temperatures, resulting in insufficient heat exchange. This further necessitates increasing the heat exchanger selection margin and raising equipment investment costs. Simultaneously, to ensure the target outlet temperature on the hot side, the total exhaust temperature on the cold side will also decrease, leading to insufficient utilization of the liquid nitrogen cooling capacity and increased liquid nitrogen consumption.

[0004] like Figure 1 As shown, in a conventional liquid nitrogen / nitrogen gas distribution method, liquid nitrogen / nitrogen gas enters through inlet a, passes through the bottom hole b, and enters the baffle plate c. However, it cannot be evenly distributed to each heat exchange tube d, especially the liquid nitrogen. When liquid nitrogen flows from the baffle plate c to the tube sheet e, it may cause excessive liquid nitrogen to enter the heat exchange tubes closer to the baffle plate c (such as d1), while the amount of liquid nitrogen entering the heat exchange tubes further away (such as d2) may be less, or even none at all. Summary of the Invention

[0005] This invention aims to solve the technical problems existing in the prior art and provides a two-phase flow distributor that adopts a multi-stage and pressure drop-free distribution method, so that the liquid nitrogen used as a refrigerant is evenly distributed in the liquid nitrogen condenser heat exchange tubes in the liquid nitrogen condensation and recovery technology of volatile organic compound (VOCs) process tail gas. This two-phase flow distributor can improve the heat exchange performance of the heat exchanger, reduce the possibility of heat exchanger frosting, effectively extend the defrosting cycle of the heat exchanger, and reduce the operating energy consumption of the system.

[0006] The technical solution of the present invention is: a two-phase flow distributor, including a distributor body, an inlet pipe at the top of the distributor body, an anti-impact sleeve at the bottom of the inlet pipe, a first outlet hole on the inlet pipe inside the anti-impact sleeve, and a second outlet hole at the bottom of the anti-impact sleeve; a mixture of nitrogen gas and liquid nitrogen enters the anti-impact sleeve from the inlet pipe for gas-liquid separation, and liquid nitrogen flows out from the second outlet hole;

[0007] Below the anti-impact sleeve is a primary perforated plate, which is fitted against the inner wall of the distributor body. The primary perforated plate is provided with multiple distribution heads, with a top inlet and a bottom outlet at the top and bottom of each distribution head, and a side inlet on the side of each distribution head. Nitrogen and liquid nitrogen are distributed in the primary stage through the primary perforated plate and the distribution heads and flow downwards.

[0008] Below the primary orifice plate is a secondary tube sheet, which is fitted against the inner wall of the distributor body. The secondary tube sheet has multiple heat exchange tubes, and each heat exchange tube has a fluid inlet at its top. The height of the fluid inlet is equal to or higher than the height of the upper surface of the secondary tube sheet. Each heat exchange tube is staggered with each distribution head. After the nitrogen and liquid nitrogen are distributed in the primary stage, they are further distributed in the secondary stage through the secondary tube sheet and the heat exchange tubes, so that the two-phase flow of nitrogen and liquid nitrogen can be evenly distributed to each heat exchange tube.

[0009] Furthermore, the upper end of the anti-impact sleeve in this invention is open, the bottom end of the inlet tube is connected to the bottom wall of the anti-impact sleeve, a plurality of first outlet holes are evenly distributed around the inlet tube, and a plurality of second outlet holes are evenly distributed on the bottom wall of the anti-impact sleeve surrounding the inlet tube.

[0010] Furthermore, in this invention, the primary orifice plate and the secondary tube sheet divide the interior of the distributor body into an upper primary distribution chamber and a lower secondary distribution chamber. The top inlet and side inlet of the distribution head are located in the primary distribution chamber, and the bottom outlet of the distribution head and the fluid inlet of the heat exchange tube are located in the secondary distribution chamber.

[0011] Furthermore, in this invention, the distance between the primary orifice plate and the secondary tube sheet is 5–200 mm.

[0012] Furthermore, in this invention, the distance between the primary orifice plate and the secondary tube sheet is 50–100 mm.

[0013] Furthermore, in this invention, the distance between the fluid inlet of the heat exchange tube and the upper surface of the secondary tube sheet is 0–20 mm.

[0014] Furthermore, in this invention, the distance between the fluid inlet of the heat exchange tube and the upper surface of the secondary tube sheet is 2 to 5 mm.

[0015] Furthermore, in this invention, the height of the lowest point of the side inlet of the dispensing head is higher than the height of the upper surface of the first-stage orifice plate.

[0016] Compared with the prior art, the present invention has the following advantages: The present invention provides a two-phase flow distributor that adopts a multi-stage and pressure-drop-free distribution method. The liquid nitrogen and nitrogen gas two-phase mixture is first separated into gas and liquid by an anti-impact sleeve, and then uniformly enters the heat exchange tubes through secondary distribution via a distribution head, a first-stage orifice plate, and a second-stage tube sheet. The liquid nitrogen / nitrogen gas distributed by this distributor can improve the heat exchange performance of the heat exchanger while reducing the possibility of frost formation, effectively extending the defrosting cycle of the heat exchanger. In addition, since the entire distribution process adopts a gravity flow distribution method, compared with conventional distribution methods, it achieves pressure-drop-free distribution and ensures the uniformity of distribution, which reduces the system pressure drop and further reduces the system's operating energy consumption. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a distributor in the prior art;

[0018] Figure 2 This is a schematic diagram of the specific structure of the present invention.

[0019] The components are: 1. Distributor body; 1a. Primary distribution chamber; 1b. Secondary distribution chamber; 2. Inlet pipe; 3. Anti-impact sleeve; 4. First outlet; 5. Second outlet; 6. Primary orifice plate; 7. Distribution head; 8. Top inlet; 9. Bottom outlet; 10. Side inlet; 11. Secondary tube sheet; 12. Heat exchange tube; 13. Fluid inlet; L1. Primary liquid level; L2. Secondary liquid level. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Example:

[0022] The accompanying drawings illustrate a specific embodiment of a two-phase flow distributor according to the present invention. Figure 2 It mainly includes a distributor body 1, with an inlet pipe 2 at the top center of the distributor body 1, and the bottom end of the inlet pipe 2 extending into the interior of the distributor body 1. The bottom end of the inlet pipe 2 is provided with an anti-impact sleeve 3, the upper end of the anti-impact sleeve 3 is open, the bottom end of the inlet pipe 2 is connected to the bottom wall of the anti-impact sleeve 3, and the bottom end of the inlet pipe 2 is closed.

[0023] The inlet pipe 2 inside the anti-impact sleeve 3 is provided with a first outlet hole 4, and there are several first outlet holes 4, which are evenly distributed around the lower part of the inlet pipe 2. The bottom of the anti-impact sleeve 3 is provided with a second outlet hole 5, and there are several second outlet holes 5, which are evenly distributed on the bottom wall of the anti-impact sleeve 3 surrounding the inlet pipe 2. The height of the anti-impact sleeve 3 is higher than the height of the first outlet hole 4.

[0024] The mixture of nitrogen gas and liquid nitrogen enters the anti-impact sleeve 3 from the inlet pipe 2 for gas-liquid separation, and the liquid nitrogen flows out from the second outlet hole 5.

[0025] Below the anti-impact sleeve 3 is a primary orifice plate 6, which is fitted against the inner wall of the distributor body 1. Multiple distribution heads 7 are mounted on the primary orifice plate 6, passing through it and sealed to it. The top and bottom of each distribution head 7 are located on the upper and lower sides of the primary orifice plate 6, respectively. Each distribution head 7 has a top inlet 8 and a bottom outlet 9, which are interconnected. A side inlet 10 is located on the side of the distribution head 7, above the primary orifice plate 6. The lowest point of the side inlet 10 is higher than the upper surface of the primary orifice plate 6, and the side inlet 10 is interconnected with the bottom outlet 9.

[0026] Nitrogen gas and liquid nitrogen are distributed in the first stage through the orifice plate 6 and the distributor head 7 and flow downwards.

[0027] A secondary tube sheet 11 is provided below the primary orifice plate 6, and the secondary tube sheet 11 is fitted to the inner wall of the distributor body 1. Multiple heat exchange tubes 12 are provided on the secondary tube sheet 11, and the heat exchange tubes 12 pass through the secondary tube sheet 11. The heat exchange tubes 12 and the secondary tube sheet 11 are sealed together. A fluid inlet 13 is provided at the top of the heat exchange tubes 12, and the height of the fluid inlet 13 is equal to or higher than the height of the upper surface of the secondary tube sheet 11.

[0028] Each heat exchange tube 12 is staggered with each distribution head 7 to prevent nitrogen gas and liquid nitrogen flowing out of the distribution head 7 from flowing directly into the heat exchange tube 12, thus failing to achieve the purpose of secondary distribution.

[0029] After primary distribution, nitrogen gas and liquid nitrogen undergo secondary distribution through secondary tube sheet 11 and heat exchange tube 12, so that the two-phase flow of nitrogen gas and liquid nitrogen can be evenly distributed to each heat exchange tube 12.

[0030] The distributor of the present invention divides the interior of the distributor body 1 into an upper primary distribution chamber 1a and a lower secondary distribution chamber 1b through a primary orifice plate 6 and a secondary tube plate 11, for secondary uniform distribution of nitrogen gas and liquid nitrogen. The top inlet 8 and side inlet 10 of the distribution head 7 are located in the primary distribution chamber 1a, and the bottom outlet 9 of the distribution head 7 and the fluid inlet 13 of the heat exchange tube 12 are located in the secondary distribution chamber 1b.

[0031] In this embodiment, the distance between the primary orifice plate 6 and the secondary tube sheet 11 is 5–200 mm. Preferably, the distance between the primary orifice plate 6 and the secondary tube sheet 11 is 50–100 mm, which is beneficial for improving the uniformity of distribution.

[0032] In this embodiment, the distance between the fluid inlet 13 of the heat exchange tube 12 and the upper surface of the secondary tube sheet 11 is 0–20 mm. Preferably, the distance between the fluid inlet 13 of the heat exchange tube 12 and the upper surface of the secondary tube sheet 11 is 2–5 mm, which is beneficial for liquid nitrogen to form a certain liquid level again on the upper surface of the secondary tube sheet 11 and to be evenly distributed.

[0033] When the distributor of the present invention is in operation, the liquid nitrogen, which is used as a refrigerant, passes through the liquid nitrogen regulating valve and pipeline. The pressure drops, causing some of the liquid nitrogen to evaporate into low-temperature nitrogen gas, which then enters the cold side of the heat exchanger from the inlet pipe 2.

[0034] Liquid nitrogen / nitrogen gas enters the heat exchanger through the first outlet 4 at the bottom of the inlet pipe 2 and enters the anti-impact sleeve 3. The nitrogen gas and liquid nitrogen mixture undergo gas-liquid separation within the anti-impact sleeve 3. The nitrogen gas enters the primary distribution chamber 1a through the upper opening of the anti-impact sleeve 3, while the liquid nitrogen flows into the primary orifice plate 6 by gravity through the second outlet 5 on the bottom wall of the anti-impact sleeve 3, gradually forming a certain liquid level on the primary orifice plate 6 until the primary liquid level L1 is reached.

[0035] The nitrogen gas filling the primary distribution chamber 1a is partially introduced into the secondary distribution chamber 1b through the top inlet 8 of the distribution head 7 and flows out through the bottom outlet 9. The other part is introduced into the secondary distribution chamber 1b through the side inlet 10 of the distribution head 7 and flows out through the bottom outlet 9.

[0036] After the liquid nitrogen level accumulated in the primary orifice plate 6 gradually exceeds the primary liquid level L1, the liquid nitrogen flows evenly into the distribution head 7 through the side inlet 10 and is discharged from the bottom outlet 9 into the secondary distribution chamber 1b, where it falls onto the secondary tube sheet 11. When the liquid nitrogen flow rate is too large and the side inlet 10 of the distribution head 7 cannot distribute the liquid nitrogen in time, and the liquid nitrogen level gradually exceeds the top of the distribution head 7, both liquid nitrogen and nitrogen gas are discharged into the secondary distribution chamber 1b through the top inlet 8.

[0037] Nitrogen is redistributed in the secondary distribution chamber 1b and enters the heat exchange tube 12 through the fluid inlet 13. Liquid nitrogen forms a certain level on the upper surface of the secondary tube sheet 11 again until it exceeds the secondary liquid level L2, at which point it automatically overflows into each heat exchange tube 12.

[0038] The above method ensures that the nitrogen gas and liquid nitrogen two-phase flow entering the heat exchanger through the inlet pipe 2 can be evenly distributed into the heat exchanger tubes 12.

[0039] Of course, the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All modifications made according to the spirit and essence of the main technical solution of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A two-phase flow distributor, characterized in that: The device includes a distributor body (1), with an inlet pipe (2) at the top and an anti-impact sleeve (3) at the bottom. The inlet pipe (2) inside the anti-impact sleeve (3) has a first outlet hole (4) and a second outlet hole (5) at the bottom. A mixture of nitrogen gas and liquid nitrogen enters the anti-impact sleeve (3) from the inlet pipe (2) for gas-liquid separation, and liquid nitrogen flows out from the second outlet hole (5). A primary perforated plate (6) is provided below the anti-impact sleeve (3). The primary perforated plate (6) is fitted against the inner wall of the distributor body (1). The primary perforated plate (6) is provided with multiple distribution heads (7). The top and bottom of the distribution head (7) are respectively provided with a top inlet (8) and a bottom outlet (9). The side of the distribution head (7) is provided with a side inlet (10). Nitrogen gas and liquid nitrogen are distributed in the primary stage through the primary perforated plate (6) and the distribution head (7) and flow downwards. A secondary tube sheet (11) is provided below the primary orifice plate (6). The secondary tube sheet (11) is fitted against the inner wall of the distributor body (1). Multiple heat exchange tubes (12) are provided on the secondary tube sheet (11). A fluid inlet (13) is provided at the top of each heat exchange tube (12). The height of the fluid inlet (13) is equal to or higher than the height of the upper surface of the secondary tube sheet (11). Each heat exchange tube (12) is staggered with each distribution head (7). After the nitrogen and liquid nitrogen are distributed in the primary stage, they are further distributed in the secondary stage through the secondary tube sheet (11) and the heat exchange tubes (12). The two-phase flow of nitrogen and liquid nitrogen can be evenly distributed to each heat exchange tube (12).

2. A two-phase flow distributor according to claim 1, characterized in that: The upper end of the anti-impact sleeve (3) is open, the bottom end of the inlet pipe (2) is connected to the bottom wall of the anti-impact sleeve (3), the first outlet hole (4) is evenly distributed around the inlet pipe (2), and the second outlet hole (5) is evenly distributed around the bottom wall of the anti-impact sleeve (3) on the periphery of the inlet pipe (2).

3. A two-phase flow distributor according to claim 1, characterized in that: The primary orifice plate (6) and the secondary tube sheet (11) divide the interior of the distributor body (1) into an upper primary distribution chamber (1a) and a lower secondary distribution chamber (1b). The top inlet (8) and side inlet (10) of the distribution head (7) are located in the primary distribution chamber (1a), and the bottom outlet (9) of the distribution head (7) and the fluid inlet (13) of the heat exchange tube (12) are located in the secondary distribution chamber (1b).

4. A two-phase flow distributor according to claim 1, characterized in that: The distance between the primary orifice plate (6) and the secondary tube sheet (11) is 5 to 200 mm.

5. A two-phase flow distributor according to claim 4, characterized in that: The distance between the primary orifice plate (6) and the secondary tube sheet (11) is 50-100 mm.

6. A two-phase flow distributor according to claim 1, characterized in that: The distance between the fluid inlet (13) of the heat exchange tube (12) and the upper surface of the secondary tube sheet (11) is 0-20 mm.

7. A two-phase flow distributor according to claim 6, characterized in that: The distance between the fluid inlet (13) of the heat exchange tube (12) and the upper surface of the secondary tube sheet (11) is 2-5 mm.

8. A two-phase flow distributor according to claim 1, characterized in that: The height of the lowest point of the side inlet (10) of the distribution head (7) is higher than the height of the upper surface of the first-stage orifice plate (6).

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