Ammonia separation plate heat exchanger unit with improved liquid storage structure

Abstract

The utility model discloses an ammonia separation plate heat exchanger unit with an improved liquid storage structure, which comprises a gas-liquid separator arranged at the upper part and a plate heat exchanger arranged at the lower part, a liquid inlet interface of the gas-liquid separator is connected with a liquid supply control valve group, a gas outlet interface of the gas-liquid separator is connected with a gas outlet pipe, and the gas outlet pipe is connected with a gas outlet pipe. The device is characterized by further comprising a vertically-arranged liquid storage barrel, a liquid outlet connector of the gas-liquid separator is connected with an upper inlet of the liquid storage barrel, a lower outlet of the liquid storage barrel is connected with an ammonia liquid inlet of the plate heat exchanger through a liquid inlet pipe, and an ammonia gas outlet of the plate heat exchanger is connected with a gas inlet connector of the gas-liquid separator through a gas return pipe. The volume of the gas-liquid separator can be greatly reduced, the filling amount of ammonia refrigerant can be effectively reduced, liquid supply and gas return can be stable, oil return is convenient, the working efficiency of a unit can be improved, and the operation and maintenance cost of the unit can be reduced.

Description

Technical Field

[0001] The utility model relates to an ammonia plate heat exchanger in an ammonia refrigeration system, in particular to an ammonia plate heat exchanger unit with an improved liquid storage structure. Background Art

[0002] The ammonia plate heat exchanger unit mainly consists of a gas-liquid separator installed on the upper part, a plate heat exchanger installed on the lower part, various connecting pipes installed between the gas-liquid separator and the plate heat exchanger, as well as liquid supply control valve group, oil return assembly, electrical control elements and other components. It is widely used in refrigeration, air conditioning, chemical, food, medicine and other industries.

[0003] The basic operating principle of this unit is as follows: high-pressure ammonia liquid is throttled and reduced to low-pressure liquid by the liquid supply control valve assembly. It then flows through the gas-liquid separator, driven by gravity, through the corresponding connecting pipes. There, it undergoes heat exchange and evaporates into low-pressure saturated steam. It then enters the gas-liquid separator for gas-liquid separation. The separated liquid remains in the gas-liquid separator, repeating the cycle. The separated gas is then drawn into the compressor in the ammonia refrigeration system. In the plate heat exchanger, the other side of the heat exchange with the ammonia liquid, a refrigerant such as water or ethylene glycol, is cooled and then used by the end user.

[0004] Currently, to ensure the normal circulation of ammonia plate heat exchanger units, liquid ammonia is usually stored in a gas-liquid separator, and the liquid level of the gas-liquid separator is controlled by interlocking with the liquid supply valve group to maintain a stable liquid level. However, this structural model requires a gas-liquid separator with a large volume ratio, resulting in an increase in the unit's space occupation, corresponding extension of various connecting pipes, and a bloated overall structure. This not only increases the ammonia liquid refrigerant charge, but also reduces the liquid supply stability, increasing the unit's operating and maintenance costs; the gas-liquid separator and plate heat exchanger also require separate oil return lines, making the process flow more complicated. How to effectively reduce the unit's refrigerant charge, ensure stable unit operation, and save production costs is a key issue currently facing ammonia plate heat exchanger equipment. Summary of the Invention

[0005] The purpose of this utility model is to provide an ammonia separator unit with an improved liquid storage structure, which can greatly reduce the volume of the gas-liquid separator, effectively reduce the charge of ammonia refrigerant, and can provide stable liquid supply, smooth gas return, and convenient oil return, which is beneficial to improving the working efficiency of the unit and reducing the cost of unit operation and maintenance.

[0006] To achieve the above-mentioned purpose, the utility model is designed with an improved ammonia plate heat exchanger unit with a liquid storage structure, which includes a gas-liquid separator arranged at the top and a plate heat exchanger arranged at the bottom. The liquid inlet interface of the gas-liquid separator is connected to the liquid supply control valve group, and the gas outlet interface of the gas-liquid separator is connected to the gas outlet pipe. The special feature is that it also includes a vertically arranged liquid storage cylinder, the liquid outlet interface of the gas-liquid separator is connected to the upper inlet of the liquid storage cylinder, and the lower outlet of the liquid storage cylinder is connected to the ammonia liquid inlet of the plate heat exchanger through the liquid inlet pipe, and the ammonia outlet of the plate heat exchanger is connected to the gas inlet interface of the gas-liquid separator through the return gas pipe.

[0007] As a preferred solution, the liquid storage cylinder is designed to have a height of 1.65 to 1.95 meters. The liquid storage cylinder serves as both a gravity-fed liquid supply line to the plate heat exchanger and a storage space to maintain the ammonia liquid level. A height of 1.65 meters or more ensures that the liquid column overcomes the operating resistance of the plate heat exchanger and pipeline resistance losses.

[0008] Furthermore, an oil collecting bag is provided at the bottom of the liquid storage cylinder, so that the lubricating oil in the ammonia separator and the heat exchanger unit can be collected here, and the oil return is extremely convenient.

[0009] Furthermore, the liquid inlet pipe is arranged horizontally and tilted, gradually rising from one end of the lower outlet of the liquid storage cylinder to one end of the ammonia liquid inlet of the plate heat exchanger. This is conducive to the normal return of lubricating oil to the oil collection bag after the ammonia plate heat exchanger unit is shut down.

[0010] Furthermore, the liquid inlet pipe is arranged with an inclined slope of 2.5-5%, so that the lubricating oil can be smoothly and smoothly guided to the oil collecting bag after shutdown.

[0011] Furthermore, the plate heat exchanger is a low-pressure-drop type heat exchanger, which can reduce the running flow resistance, reduce the height of the liquid column, and ensure stable liquid supply.

[0012] As a preferred solution, two return air pipes are provided. These pipes extend from the bottom of the gas-liquid separator into its inner cavity and extend outward in an elbow structure to the end caps of the gas-liquid separator. Optimizing the structural design of the return air pipes can achieve multi-stage gas-liquid separation and ensure effective return air.

[0013] Furthermore, the system also includes a tubular liquid level sensor interlocked with the liquid supply valve assembly. The tubular liquid level sensor is arranged parallel to one side of the liquid storage cylinder and is used to detect and control the liquid level from the liquid storage cylinder to the inner cavity of the gas-liquid separator. Interlocking the liquid level of the injection cylinder with the liquid supply valve assembly ensures liquid level stability.

[0014] Furthermore, the system also includes a magnetic flap level gauge, which is arranged parallel to the outer side of the tubular liquid level sensor. This magnetic flap level gauge can be set to a liquid level alarm function as needed. It works in conjunction with the tubular liquid level sensor and the liquid supply valve assembly to control the liquid level from the liquid storage cylinder to the gas-liquid separator in real time, ensuring stable operation of the unit.

[0015] The advantages of this utility model lie in the fact that it replaces the existing liquid outlet pipe in the ammonia plate heat exchanger unit with a liquid reservoir. The reservoir serves a dual purpose: it serves as both a storage space for the ammonia liquid in the unit and a channel for gravity-feeding the liquid to the plate heat exchanger. This eliminates the need for liquid storage in the upper gas-liquid separator, which only considers the atmospheric space. This significantly reduces the volume of the gas-liquid separator and effectively reduces the ammonia refrigerant charge. Furthermore, when used in conjunction with a low-pressure-drop heat exchanger, it further reduces the flow resistance, reduces the required liquid column height, and ensures stable liquid supply. When combined with a dual-channel return air pipe, it further enhances the return air effect and achieves multi-stage gas-liquid separation. Furthermore, due to the reduced volume of the gas-liquid separator and the presence of the liquid reservoir, which both reduces flow resistance and increases liquid storage buffering capacity, its height is designed to be much lower than the original liquid outlet pipe. This results in a compact unit structure, a small footprint, high efficiency, and reduced operating and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the connection relationship of an ammonia plate heat exchanger unit with an improved liquid storage structure.

[0017] Figure 2 for Figure 1 The main structural diagram of the ammonia distribution plate exchange unit is shown.

[0018] Figure 3 for Figure 2 Schematic diagram of the left view structure.

[0019] Figure 4 for Figure 1 Schematic diagram of the partial structure of the gas-liquid separator and other related components.

[0020] Figure 5 for Figure 1 Schematic diagram of the partial structure of the liquid storage cylinder and other related components.

[0021] The components in the figure are numbered as follows: gas-liquid separator 1, plate heat exchanger 2, liquid supply control valve group 3, liquid storage cylinder 4, return air pipe 5, tubular liquid level sensor 6, outlet pipe 7, magnetic flap level gauge 8, liquid inlet pipe 9, oil collecting bag 10. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but these embodiments should not be construed as limiting the present invention.

[0023] like Figures 1 to 5 The illustrated improved ammonia plate heat exchanger unit with a liquid storage structure primarily consists of a gas-liquid separator 1, a plate heat exchanger 2, a liquid supply control valve assembly 3, a liquid storage cylinder 4, a gas return pipe 5, an air outlet pipe 7, and a liquid inlet pipe 9. The gas-liquid separator 1 and the plate heat exchanger 2 are arranged in an upper-lower configuration. The liquid inlet of the gas-liquid separator 1 is connected to the liquid supply control valve assembly 3, allowing high-pressure ammonia liquid to enter the gas-liquid separator 1 after throttling and reducing its pressure. The gas outlet of the gas-liquid separator 1 is connected to the air outlet pipe 7, which transports the separated gas to the compressor in the ammonia refrigeration system. The liquid storage cylinder 4 is arranged in an upright configuration. The liquid outlet of the gas-liquid separator 1 is connected to the upper inlet of the liquid storage cylinder 4. The lower outlet of the liquid storage cylinder 4 is connected to the ammonia liquid inlet of the plate heat exchanger 2 via a liquid inlet pipe 9, allowing low-pressure ammonia liquid in the gas-liquid separator 1 to enter the plate heat exchanger 2 by gravity. The ammonia outlet of plate heat exchanger 2 is connected to the air inlet of gas-liquid separator 1 via return pipe 5, allowing low-pressure saturated steam in plate heat exchanger 2 to re-enter gas-liquid separator 1. An oil collection bag 10 is provided at the bottom of liquid storage cylinder 4 to centrally collect lubricating oil from the ammonia plate heat exchanger unit.

[0024] Specifically described: The height of the liquid storage cylinder 4 can be controlled in the range of 1.75 to 1.85 meters, ensuring that the height of the liquid column is controlled at about 1.8 meters. The caliber of the liquid storage cylinder 4 can be designed according to different operating conditions, so as to reduce the flow resistance and ensure the buffering capacity of the liquid storage. The plate heat exchanger 2 adopts a low-pressure drop type heat exchanger to reduce the height of the liquid column that needs to be provided. The liquid inlet pipe 9 adopts a horizontal inclined arrangement, which gradually rises from one end of the lower outlet of the liquid storage cylinder 4 to one end of the ammonia liquid inlet of the plate heat exchanger 2. The slope of the inclined arrangement can be controlled between 3.5 and 4.0% to ensure that the lubricating oil can normally slope back to the oil collection bag 10 after shutdown.

[0025] In this embodiment, two return air pipes 5 are provided. The two return air pipes 5 extend from the bottom of the gas-liquid separator 1 into its inner cavity and extend outward in an elbow structure to the end caps of the gas-liquid separator 1. The optimized return air circuit with dual return air pipes can achieve multi-stage gas-liquid separation and improve the return air effect.

[0026] In this embodiment, a tubular liquid level sensor 6 and a magnetic flap liquid level gauge 8 are also provided. The tubular liquid level sensor 6 is arranged in parallel on one side of the liquid storage cylinder 4, and is used to detect and control the liquid level from the liquid storage cylinder 4 to the inner cavity of the gas-liquid separator 1; the magnetic flap liquid level gauge 8 is arranged in parallel on the outside of the tubular liquid level sensor 6. The liquid level from the liquid storage cylinder 4 to the inner cavity of the gas-liquid separator 1 is controlled by the tubular liquid level sensor 6 and the liquid supply control valve group 3 in an interlocking manner, so that the liquid level can be maintained stable. The magnetic flap liquid level gauge 8 has a liquid level alarm function, and cooperates with the tubular liquid level sensor 6 and the liquid supply control valve group 3 to adjust the liquid level height from the liquid storage cylinder 4 to the inner cavity of the gas-liquid separator 1 in real time to ensure stable operation of the unit. The above control part is the existing technology and will not be elaborated here.

[0027] During operation of the improved ammonia plate heat exchanger unit with a liquid storage structure in this embodiment, high-pressure ammonia liquid is throttled and reduced in pressure by the liquid supply control valve assembly 3 to low-pressure ammonia liquid, which then enters the gas-liquid separator 1. Then, under its own gravity, it passes through the liquid storage cylinder 4 and the liquid inlet pipe 9 into the plate heat exchanger 2. There, it undergoes heat exchange and evaporates into low-pressure saturated steam. The steam then enters the gas-liquid separator 1 through the return pipe 5 for gas-liquid separation. The separated liquid remains in the gas-liquid separator 1, continuing the aforementioned cycle. The separated gas is discharged through the gas outlet pipe 7 and drawn into the compressor of the ammonia refrigeration system. In the plate heat exchanger 2, the refrigerant exchanging heat with the ammonia liquid is water, which is cooled and provided to the end user.

[0028] In summary, the technical solution of this utility model significantly reduces the volume of the gas-liquid separator and effectively reduces the ammonia refrigerant charge. The liquid storage cylinder reduces flow resistance and increases liquid buffering capacity, ensuring a stable liquid level. Its height is designed to be much lower than the original liquid outlet pipe, resulting in a compact unit structure, small footprint, high efficiency, and reduced operating and maintenance costs.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An improved ammonia separator plate heat exchanger unit with a liquid storage structure, comprising a gas-liquid separator (1) arranged at the top and a plate heat exchanger (2) arranged at the bottom, wherein the liquid inlet interface of the gas-liquid separator (1) is connected to a liquid supply control valve group (3), and the gas outlet interface of the gas-liquid separator (1) is connected to a gas outlet pipe (7), characterized in that: The invention also includes a liquid storage cylinder (4) arranged vertically, wherein the liquid outlet interface of the gas-liquid separator (1) is connected to the upper inlet of the liquid storage cylinder (4), the lower outlet of the liquid storage cylinder (4) is connected to the ammonia liquid inlet of the plate heat exchanger (2) through a liquid inlet pipe (9), and the ammonia gas outlet of the plate heat exchanger (2) is connected to the gas inlet interface of the gas-liquid separator (1) through a gas return pipe (5).

2. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: The designed height of the liquid storage cylinder (4) is 1.65-1.95 m.

3. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: An oil collecting bag (10) is provided at the bottom of the liquid storage cylinder (4).

4. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: The liquid inlet pipe (9) is arranged in a horizontal tilted state, and gradually rises from one end of the lower outlet of the liquid storage cylinder (4) to one end of the ammonia liquid inlet of the plate heat exchanger (2).

5. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 4, characterized in that: The liquid inlet pipe (9) has an inclined arrangement slope of 2.5-5%.

6. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: The plate heat exchanger (2) is a low pressure drop type heat exchanger.

7. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: Two return air pipes (5) are provided, and the two return air pipes (5) extend from the bottom of the gas-liquid separator (1) into the inner cavity thereof, and are in an elbow structure and extend outwards to the end caps at both ends of the gas-liquid separator (1).

8. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 1, characterized in that: It also includes a tubular liquid level sensor (6) interlocked with the liquid supply control valve group (3), wherein the tubular liquid level sensor (6) is arranged in parallel on one side of the liquid storage cylinder (4) and is used to detect and control the liquid level from the liquid storage cylinder (4) to the inner cavity of the gas-liquid separator (1).

9. The liquid storage structure improved ammonia plate heat exchanger unit according to claim 8, characterized in that: It also includes a magnetic flap liquid level gauge (8), which is arranged in parallel on the outside of the tubular liquid level sensor (6).

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