BOG compressor double-cooling system

Abstract

The utility model belongs to the technical field of compressor cooling, and relates to a BOG compressor double-cooling system which comprises a cooling medium buffer tank, a circulating water heat exchanger, an air cooler and a BOG compressor unit. One end of the cooling medium buffer tank is communicated with the other end of the cooling medium buffer tank through the circulating water heat exchanger and the BOG compressor unit in sequence to form a cooling loop; the air cooler and the circulating water heat exchanger are arranged in parallel; one end of the air cooler is communicated with a pipeline between the cooling medium buffer tank and the circulating water heat exchanger; and the other end of the air cooler is communicated with a pipeline between the circulating water heat exchanger and the BOG compressor unit. By arranging the cooling medium buffer tank, the circulating water heat exchanger, the air cooler and the BOG compressor unit, double cooling of the BOG compressor is achieved, water resources are saved, electric energy consumption is reduced, and environmental pollution is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of compressor cooling, and relates to a dual cooling system for BOG compressors. Background Technique

[0002] A large amount of cryogenic flash gas (abbreviated as BOG) is generated during the storage, pipeline transportation, and loading and unloading of the product LNG in the liquefied natural gas production device. The BOG is pressurized by a compressor to achieve BOG recovery, and the cooling of the BOG compressor relies on the cooling capacity provided by a circulating water supply device. For example, the Chinese patent document with the application number CN202220772249.4 discloses a BOG compressor inter-stage cooling system. There are various ways to cool the medium in the cylinder of the BOG compressor: the cooling source medium is cooling water. However, when the liquefied natural gas production device needs to stop due to insufficient upstream gas source, inspection and maintenance, etc., in order to cool the BOG compressor, it is still necessary to maintain the normal operation of the circulating water supply system. This single cooling method not only causes waste of circulating water and waste of power consumption, resulting in increased costs, but also is not conducive to the inspection and maintenance work of the circulating water system; once the circulating water supply system stops running, the BOG compressor faces the risk of stopping operation. At this time, the generated BOG has to be directly discharged to the flare system, which will cause certain economic losses. At the same time, direct discharge will also increase the emission of greenhouse effect gases, resulting in environmental pollution.

[0003] To sum up, the existing single circulating water cooling operation mode of the BOG compressor leads to defects such as resource waste, energy waste, and environmental pollution caused by the shutdown of the compressor. Summary of the Utility Model

[0004] Aiming at the defects such as resource waste, energy waste, and environmental pollution caused by the shutdown of the BOG compressor due to the existing single circulating water cooling operation mode of the BOG compressor, the utility model provides a dual cooling system for BOG compressors.

[0005] The utility model realizes the dual cooling of the BOG compressor by setting a cooling medium buffer tank, a circulating water heat exchanger, an air cooler, and a BOG compressor unit, saves water resources, reduces power consumption, and avoids environmental pollution.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A BOG compressor dual cooling system includes a cooling medium buffer tank, a circulating water heat exchanger, an air cooler, and a BOG compressor unit; one end of the cooling medium buffer tank is sequentially connected to the other end of the cooling medium buffer tank through the circulating water heat exchanger and the BOG compressor unit to form a cooling loop; the air cooler is arranged in parallel with the circulating water heat exchanger, and one end of the air cooler is connected to the pipeline between the cooling medium buffer tank and the circulating water heat exchanger; the other end of the air cooler is respectively connected to the pipeline between the circulating water heat exchanger and the BOG compressor unit.

[0008] Further defined, a booster pump is also arranged between the cooling medium buffer tank and the circulating water heat exchanger; one end of the air cooler is connected to the pipeline between the booster pump and the circulating water heat exchanger.

[0009] Further defined, a first control valve is arranged between the booster pump and the circulating water heat exchanger; one end of the air cooler is connected to the first control valve.

[0010] Further defined, a second control valve is arranged between the circulating water heat exchanger and the BOG compressor unit; the other end of the air cooler is connected to the second control valve.

[0011] Further defined, the BOG compressor dual cooling system further includes a circulating water supply device that is connected to the circulating water heat exchanger and forms a circulating loop.

[0012] Further defined, a cooling medium inlet, a cooling medium outlet, a circulating water inlet, and a circulating water outlet are respectively arranged on the circulating water heat exchanger; the booster pump is connected to the cooling medium inlet through the first control valve; the cooling medium outlet is connected to the BOG compressor unit through the second control valve; one end of the circulating water supply device is sequentially connected to the other end of the circulating water supply device after passing through the circulating water inlet and the circulating water outlet.

[0013] The beneficial effects of the present utility model are:

[0014] 1. By setting a cooling medium buffer tank, a circulating water heat exchanger, an air cooler, and a BOG compressor unit, the present utility model realizes the dual cooling of the BOG compressor, saves water resources, reduces power consumption, and avoids environmental pollution.

[0015] 2. In the present utility model, by setting a booster pump to boost the cooling medium, the pressure requirements of subsequent processes are met, the stability of the cooling medium during cooling operation is ensured, and the cooling effect is improved.

[0016] 3. In the present utility model, by setting a first control valve and a second control valve, it is convenient to switch between the two cooling methods according to the operating conditions of the BOG compressor and the external environmental temperature. It is not only flexible and convenient, adapts to complex environmental and working conditions, but also can maintain the normal and stable operation of the BOG compressor unit. Brief Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the BOG compressor dual cooling system provided by the present utility model;

[0018] Figure 2 It is a schematic diagram of the BOG compressor unit structure;

[0019] Wherein:

[0020] 10 - Cooling medium buffer tank; 20 - Booster pump; 30 - First control valve; 40 - Circulating water heat exchanger; 50 - Circulating water supply device; 60 - Second control valve; 70 - Air cooler; 80 - BOG compressor unit; 801 - BOG heat exchanger; 802 - Lubricating oil cooler; 803 - Packing cooling device. Detailed Embodiment

[0021] The following elaborates on the preferred embodiments of the present utility model in conjunction with the accompanying drawings, so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, thereby making the protection scope of the present utility model more clearly defined.

[0022] Embodiment 1

[0023] Refer to Figure 1 , the BOG compressor dual cooling system provided in this embodiment includes a cooling medium buffer tank 10, a circulating water heat exchanger 40, an air cooler 70, and a BOG compressor unit 80; one end of the cooling medium buffer tank 10 is sequentially connected to the other end of the cooling medium buffer tank 10 through the circulating water heat exchanger 40 and the BOG compressor unit 80 to form a cooling circuit; one end of the cooling medium buffer tank 10 is sequentially connected to the other end of the cooling medium buffer tank 10 through the air cooler 70 and the BOG compressor unit 80 to form a cooling circuit. The air cooler 70 and the circulating water heat exchanger 40 are arranged in parallel, and one end of the air cooler 70 is connected to the pipeline between the cooling medium buffer tank 10 and the booster pump 20; the other end of the air cooler 70 is connected to the pipeline between the BOG compressor unit 80.

[0024] Specifically, the bottom end (i.e., the output end) of the cooling medium buffer tank 10 passes through the circulating water heat exchanger 40 and the BOG compressor unit 80 and is connected from the top end (i.e., the input end) of the cooling medium buffer tank 10 to form a cooling circuit (also called a circulating water cooling circuit); at the same time, the air cooler 70 and the circulating water heat exchanger 40 are arranged in parallel. After the bottom end (i.e., the output end) of the cooling medium buffer tank 10 passes through the air cooler 70 and the BOG compressor unit 80, one end of the cooling medium buffer tank 10, the air cooler 70, the BOG compressor unit 80, and the other end of the cooling medium buffer tank 10 form a cooling circuit (also called an air cooling circuit).

[0025] In the use of this embodiment, the cooling medium enters the BOG compressor unit 80 for cooling after being cooled by the circulating water heat exchanger 40, and the cooled cooling medium returns to the cooling medium buffer tank 10, and circulates in this way to achieve cooling recovery; at the same time, after being cooled by the air cooler 70, the cooling medium also enters the BOG compressor unit 80 for cooling, thus forming a dual cooling system. While the BOG compressor unit 80 is not stopped, the BOG compressor unit 80 is cooled to achieve BOG recovery, avoiding direct emission of BOG when the BOG compressor stops, resulting in environmental pollution and economic losses; in addition, two methods of using the circulating water heat exchanger 40 and the air cooler 70 for cooling save the consumption of water resources and electric energy resources, improve the cooling effect, and greatly reduce the cooling cost.

[0026] See Figure 2 , the BOG compressor unit 80 is a conventional BOG compressor device, and there are many equipment in the whole device. Since the BOG compressor needs to be cooled during use, preferably, for example, a BOG heat exchanger 801, a lubricating oil cooler 802 and a packing cooling device 803 are provided. The BOG heat exchanger 801 is used to exchange heat and cool the compressed gas of the BOG compressor to achieve BOG recovery; the lubricating oil cooler 802 is used to cool the lubricating oil of the BOG compressor, and the packing cooling device 803 is used to cool the packing of the BOG compressor. However, since the temperatures of the BOG heat exchanger 801, the lubricating oil cooler 802 and the packing cooling device 803 increase after exchanging heat with the internal medium of the compressor, it is not conducive to the operation of the compressor. The dual cooling system of this embodiment is used to cool the components of the above BOG compressor unit 80.

[0027] Preferably, the bottom of the cooling medium buffer tank 10 enters the cooling main pipe after passing through the circulating water heat exchanger 40 or the air cooler 70. The cooling main pipe is divided into three branches. The first branch returns to the top of the cooling medium buffer tank 10 after passing through the BOG heat exchanger 801, the second branch returns to the top of the cooling medium buffer tank 10 after passing through the lubricating oil cooler 802, and the third branch returns to the top of the cooling medium buffer tank 10 after passing through the packing cooling device 803, respectively for heat exchange cooling, taking away the heat generated in the BOG compressor unit 80 and maintaining the stable operation of the compressor. And when the cooling medium cools the components in the BOG compressor unit 80, it only indirectly cools from the outside without directly contacting the medium inside the BOG compressor unit 80 for direct cooling.

[0028] Embodiment 2

[0029] On the basis of Embodiment 1, the BOG compressor dual cooling system provided in this embodiment further sets a booster pump 20 between the cooling medium buffer tank 10 and the circulating water heat exchanger 40; one end of the air cooler 70 is communicated with the pipeline between the booster pump 20 and the circulating water heat exchanger 40.

[0030] In this embodiment, a first control valve 30 is provided between the booster pump 20 and the circulating water heat exchanger 40; one end of the air cooler 70 is communicated with the first control valve 30.

[0031] In this embodiment, a second control valve 60 is provided between the circulating water heat exchanger 40 and the BOG compressor unit 80; the other end of the air cooler 70 is communicated with the second control valve 60.

[0032] In this embodiment, the booster pump 20 boosts the cooling medium to meet the pressure requirements for the subsequent operation of the circulating water heat exchanger 40, the air cooler 70, and the BOG compressor unit 80, ensuring that the cooling medium enters the subsequent system smoothly and quickly for cooling. The pressure parameter of the booster pump 20 is 0.4 MpaG to 0.7 MpaG.

[0033] In this embodiment, both the first control valve 30 and the second control valve 60 are three-way valves; in this way, the switching of two cooling circuits (circulating water cooling circuit and air cooling circuit) is realized through the first control valve 30 and the second control valve 60, which is convenient and flexible.

[0034] In this embodiment, the first cooling operation mode is circulating water cooling. At this time, when the liquefaction device is operating, cooling is carried out by circulation. The cooling medium buffer tank 10 stores the cooling medium. After the cooling medium flows through the booster pump 20 for boosting, it enters the first control valve 30. The connection pipeline between the first control valve 30 and the circulating water heat exchanger 40 is opened, and the communication pipeline between the first control valve 30 and the air cooler 70 is closed. After the cooling medium enters the circulating water heat exchanger 40 for heat exchange and cooling, it enters the second control valve 60. At this time, the connection pipeline between the second control valve 60 and the BOG compressor unit 80 is opened, and the communication pipeline between the second control valve 60 and the air cooler 70 is closed. After the cooling medium exchanges heat with the BOG compressor unit 80 for cooling, the cooling medium returns to the cooling medium buffer tank 10 for storage.

[0035] In this embodiment, the second cooling operation mode is air cooling. This is because when the liquefaction device is shut down, the supply of circulating water stagnates. The cooling medium stored in the cooling medium buffer tank 10 flows through the booster pump 20 for boosting, then enters the first control valve 30. The connection pipeline between the first control valve 30 and the air cooler 70 is opened, and the communication pipeline between the first control valve 30 and the circulating water heat exchanger 40 is closed. After the cooling medium enters the air cooler 70 for heat exchange, it enters the second control valve 60. The connection pipeline between the second control valve 60 and the BOG compressor unit 80 is opened, and the communication pipeline between the second control valve 60 and the circulating water heat exchanger 40 is closed. After the cooling medium exchanges heat with the BOG compressor unit 80, it returns to the cooling medium buffer tank 10 for storage through the pipeline.

[0036] During implementation, the two cooling methods of circulating water cooling and air cooling can be used simultaneously, or either cooling method can be adopted. When the ambient temperature in summer is higher than the design temperature of the circulating water system, if circulating water is used for cooling at this time, a large amount of circulating water is consumed. Then, the second cooling operation method can be adopted to air-cool the BOG compressor unit 80 to maintain the normal operation of the system.

[0037] Embodiment 3

[0038] The BOG compressor dual cooling system further includes a circulating water supply device 50 that is connected to the circulating water heat exchanger 40 to form a circulating loop.

[0039] In this embodiment, the circulating water supply device 50 is used to circulate cooling water for the circulating water heat exchanger 40.

[0040] In this embodiment, a cooling medium inlet, a cooling medium outlet, a circulating water inlet, and a circulating water outlet are respectively provided on the circulating water heat exchanger 40; the cooling medium inlet and the cooling medium outlet are connected to form a cooling medium passage; the circulating water inlet and the circulating water outlet are connected to form a circulating water passage; the cooling medium passage and the circulating water passage are connected, that is, the cooling medium and the circulating water flow through two pipelines respectively, and the flowing direction of the circulating water and the flowing direction of the cooling medium form a countercurrent. The booster pump 20 is connected to the cooling medium inlet through the first control valve 30; the cooling medium outlet is connected to the BOG compressor unit 80 through the second control valve 60 to facilitate the cooling medium to enter the circulating water heat exchanger 40.

[0041] One end of the circulating water supply device 50 is connected to the other end of the circulating water supply device 50 after passing through the circulating water inlet and the circulating water outlet in sequence. The circulating cooling water enters the circulating water heat exchanger 40 through the circulating water inlet. After exchanging heat with the cooling medium, the circulating cooling water flows out from the circulating water outlet and returns to the circulating water supply device 50 after the heat of the cooling medium is taken away, realizing the recycling of the cooling water.

[0042] The above are only the embodiments of the present invention, and do not limit the protection scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the protection scope of the present invention by the same token.

Claims

1. A BOG compressor dual cooling system, characterized in that: The invention comprises a cooling medium buffer tank (10), a circulating water heat exchanger (40), an air cooler (70) and a BOG compressor unit (80); one end of the cooling medium buffer tank (10) is connected to the other end of the cooling medium buffer tank (10) through the circulating water heat exchanger (40) and the BOG compressor unit (80) in sequence, so as to form a cooling circuit; the air cooler (70) and the circulating water heat exchanger (40) are arranged in parallel, and one end of the air cooler (70) is connected to the pipeline between the cooling medium buffer tank (10) and the circulating water heat exchanger (40); and the other end of the air cooler (70) is respectively connected to the pipeline between the circulating water heat exchanger (40) and the BOG compressor unit (80).

2. The BOG compressor dual cooling system according to claim 1, characterized in that: A booster pump (20) is also provided between the cooling medium buffer tank (10) and the circulating water heat exchanger (40); one end of the air cooler (70) is connected to a pipeline between the booster pump (20) and the circulating water heat exchanger (40).

3. The BOG compressor dual cooling system according to claim 2, characterized in that: A first control valve (30) is provided between the booster pump (20) and the circulating water heat exchanger (40); one end of the air cooler (70) is in communication with the first control valve (30).

4. The BOG compressor dual cooling system according to claim 3, characterized in that: A second control valve (60) is provided between the circulating water heat exchanger (40) and the BOG compressor unit (80); the other end of the air cooler (70) is in communication with the second control valve (60).

5. The BOG compressor dual cooling system according to claim 4, characterized in that: The BOG compressor dual cooling system further comprises a circulating water supply device (50) which is in communication with the circulating water heat exchanger (40) and forms a circulating loop.

6. The BOG compressor dual cooling system according to claim 5, characterized in that: The circulating water heat exchanger (40) is respectively provided with a cooling medium inlet, a cooling medium outlet, a circulating water inlet and a circulating water outlet; the booster pump (20) is connected to the cooling medium inlet via a first control valve (30); the cooling medium outlet is connected to a BOG compressor unit (80) via a second control valve (60); one end of the circulating water supply device (50) is connected to the other end of the circulating water supply device (50) via the circulating water inlet and the circulating water outlet in sequence.

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