Heat sharing system of liquefied gas system and air compression system

Abstract

The utility model belongs to the technical field of chemical equipment, and particularly relates to a heat sharing system of a liquefied gas system and an air compression system, in the system, the air compression system comprises an air compressor, a freezing dryer and a compressed gas storage tank which are sequentially connected in series, and the liquefied gas system comprises a liquefied gas storage tank, a gasifier and a gasified gas storage tank which are sequentially connected in series. A refrigerant channel and a heating medium channel are arranged in the heat exchanger, an inlet of the refrigerant channel is connected with the liquefied gas storage tank through a third input pipe, and an outlet of the refrigerant channel is connected with a second input pipe on the inlet side of the gasifier through a third output pipe. Meanwhile, an inlet of the heating medium channel is connected with a first input pipe on the inlet side of the refrigeration dryer through a fourth input pipe, and an outlet of the heating medium channel is connected with a first output pipe on the outlet side of the refrigeration dryer through a fifth output pipe, so that the purpose of cooling high-temperature compressed air by using liquefied gas is achieved; and the energy consumption is reduced, and meanwhile, the original production lines of the air compression system and the liquefied gas system do not need to be greatly changed.

Description

Technical Field

[0001] This utility model belongs to the field of chemical equipment technology, specifically relating to a heat sharing system for a liquefied gas system and an air compressor system. Background Technology

[0002] The compressed air system uses an air compressor unit to compress air. The compressed air passes through an air cooler, a compressed air buffer tank, a refrigerated dryer, and a dryer in sequence, and finally enters a compressed air storage tank to be delivered to each user unit. Currently, this process flow post-processing system has the problem of high energy consumption.

[0003] The liquid nitrogen system pressurizes liquid nitrogen from a storage tank, then passes it through a vaporizer into a nitrogen storage tank before delivering it to various user units. Currently, this process suffers from wasted cooling capacity and the need for steam heating to melt ice in cold weather.

[0004] Currently, both systems have the following problems: the compressed air system produces compressed air with a high and unstable dew point temperature, and the use of refrigerated dryers increases the production cost of compressed air. The liquid nitrogen system, during use, absorbs a large amount of heat from the air during the vaporization process, resulting in a loss of cooling capacity and increasing the cost of nitrogen usage. Furthermore, large-scale use of liquid nitrogen can lead to insufficient vaporization and low temperatures affecting the reliability of equipment and facilities.

[0005] Chinese patent document CN217504081U (202221230518.0) discloses a system for co-producing instrument gas and nitrogen. This system can use liquid nitrogen to cool high-temperature compressed air, saving cooling water and reducing scaling inside the heat exchanger. However, this system does not consider the problem of insufficient liquid nitrogen supply. The cooling efficiency of the cooling water in the second refrigerant channel of the heat exchanger is too low to meet the cooling requirements of high-temperature compressed air, and it is prone to causing unstable dew point temperature. Utility Model Content

[0006] The main purpose of this utility model is to provide a heat sharing system for a liquefied gas system and an air compressor system. By using a heat exchanger to integrate the two systems, the cold energy of the liquefied gas system can be recovered and the problem of vaporizer icing can be reduced. At the same time, the air compressor system can achieve energy saving and consumption reduction, reduce the manufacturing cost of compressed air, and will not affect the original production lines of the liquefied gas system and air compressor system, which is conducive to industrial upgrading and transformation.

[0007] The technical problem to be solved by this utility model is achieved by the following technical solution: a heat sharing system for a liquefied gas system and an air compressor system, including an air compressor system, a liquefied gas system and a heat exchanger;

[0008] The air compressor system includes an air compressor, a refrigerated dryer, and a compressed air storage tank connected in series. The refrigerated dryer is provided with a first input pipe and a first output pipe at both ends. A first valve and a second valve are provided on the first input pipe and the first output pipe, respectively.

[0009] The liquefied gas system includes a liquefied gas storage tank, a vaporizer, and a vaporized gas storage tank connected in series. The vaporizer is provided with a second input pipe and a second output pipe at its two ends, and a third valve is provided on the second input pipe.

[0010] The heat exchanger is provided with a refrigerant channel and a heat medium channel. The inlet of the refrigerant channel is connected to the liquefied gas storage tank through a third input pipe, and the outlet of the refrigerant channel is connected to the second input pipe through a third output pipe. The connection between the third output pipe and the second input pipe is located on the side of the third valve outlet.

[0011] The inlet of the heat medium channel is connected to the first inlet pipe through the fourth inlet pipe, and the connection between the fourth inlet pipe and the first inlet pipe is located on the side of the first valve inlet.

[0012] The outlet of the heat medium channel is connected to the first input pipe through the fourth output pipe, and the connection between the fourth output pipe and the first input pipe is located on the side of the first valve outlet.

[0013] The outlet of the heat medium channel is connected to the first outlet pipe through the fifth outlet pipe, and the connection between the fifth outlet pipe and the first outlet pipe is located on the side of the second valve outlet.

[0014] Control valves are installed on the third input pipe, the third output pipe, the fourth input pipe, the fourth output pipe, and the fifth output pipe.

[0015] Preferably, this invention also includes a main output valve located on the outlet side of the heat medium channel, with the fourth and fifth output pipes respectively connected to the outlet of the main output valve. When a heat exchanger is not used to cool the compressed air, the main output valve can simultaneously control the fourth and fifth output pipes to disconnect, improving control efficiency and eliminating the need to separately close the control valves on the fourth and fifth output pipes.

[0016] In a preferred embodiment of this invention, the compressed air system further includes an air condenser and a compressed air buffer tank connected in sequence.

[0017] The air condenser is connected to the air compressor, and the compressed air buffer tank is connected to the refrigerated dryer. The air condenser is used to condense and remove water from the high-temperature compressed air, and the compressed air buffer tank is used to store the water-removed high-temperature compressed air.

[0018] Preferably, the air compressor system further includes a first oil separator disposed between the air condenser and the air compressor, and between the compressed air buffer tank and the refrigerated dryer. During the air compressor's compression of air, a large amount of lubricating oil vapor is mixed into the compressed air. To reduce the impact on the heat exchange efficiency of the refrigerated dryer and the liquefied gas cooling recovery device, the first oil separator is used to remove oil from the high-temperature compressed air. To reduce wear on the first oil separator, two first oil separators are used for staged oil removal.

[0019] Preferably, the compressed air system further includes a dryer disposed between the refrigerated dryer and the compressed air storage tank. Since the refrigerated dryer has limited drying efficiency, a dryer is used to further dry the cooled compressed air in order to further reduce the dew point of the compressed air.

[0020] In a preferred embodiment of this invention, the compressed air system further includes a second oil separator disposed between the refrigerated dryer and the dryer, and between the dryer and the compressed air storage tank. Since the dryer has strict requirements regarding the oil content in the gas, the second oil separator further removes oil from the cooled compressed air. Furthermore, by installing a second oil separator between the refrigerated dryer and the dryer, and between the dryer and the compressed air storage tank, a staged oil removal operation is performed, reducing the requirements for the oil removal efficiency of the second oil separator and lowering subsequent maintenance costs.

[0021] Preferably, this invention also includes a temperature sensor, which is disposed on the first output pipe and located on the side away from the refrigerated dryer at the connection between the fifth output pipe and the first output pipe. The temperature sensor on the first output pipe is used to detect in real time whether the temperature of the cooled compressed air meets the dew point requirements, thereby allowing selection of a separate cooling mode for the heat exchanger, a series cooling mode for the heat exchanger and the refrigerated dryer, or adjustment of the liquefied gas flow rate or the cooling power of the refrigerated dryer to meet different cooling needs.

[0022] Preferably, the heat exchanger of this utility model is a U-tube heat exchanger. The tube bundle of the U-tube heat exchanger can expand and contract freely, and will not generate thermal stress due to the temperature difference between the tube and the shell, thus having good thermal compensation performance; the tube pass is a double pass, with a long flow path and a high flow rate, resulting in good heat transfer performance; and it has strong pressure resistance, meeting the needs of compressed air cooling.

[0023] Preferably, the heat exchanger of this invention is made of stainless steel, which has better low-temperature resistance and avoids damage to the heat exchanger caused by low-temperature liquefied gas.

[0024] Preferably, this invention also includes a sixth output pipe, the outlet of which is connected to the vaporized gas storage tank via the refrigerant channel. A control valve is installed on the sixth output pipe. After the liquefied gas is completely vaporized in the heat exchanger, it can be directly fed into the vaporized gas storage tank through the sixth output pipe.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows: In this utility model, the air compressor system includes an air compressor, a refrigerated dryer, and a compressed gas storage tank connected in series; the liquefied gas system includes a liquefied gas storage tank, a vaporizer, and a vaporized gas storage tank connected in series; and the heat exchanger is provided with a refrigerant channel and a heat medium channel. In this utility model, the inlet of the refrigerant channel is connected to the liquefied gas storage tank through a third input pipe, and the outlet of the refrigerant channel is connected to the second input pipe on the inlet side of the vaporizer through a third output pipe. At the same time, the inlet of the heat medium channel is connected to the first input pipe on the inlet side of the refrigerated dryer through a fourth input pipe, and the outlet of the heat medium channel is connected to the first output pipe on the outlet side of the refrigerated dryer through a fifth output pipe. This achieves the purpose of using liquefied gas to cool high-temperature compressed air, saving energy consumption while requiring no major modifications to the original production lines of the air compressor system and the liquefied gas system, which is conducive to production line upgrades.

[0026] Furthermore, by controlling the valves on each pipeline, this invention enables the cooling of high-temperature compressed air using a refrigerated dryer alone, a heat exchanger alone, or a combination of a heat exchanger and a refrigerated dryer in series. Using a heat exchanger alone or a combination of a heat exchanger and a refrigerated dryer in series can reduce the manufacturing cost of compressed air.

[0027] This invention uses high-temperature compressed air to heat the liquefied gas in a heat exchanger before the gasifier vaporizes it, which reduces the load on the gasifier and prevents the gasifier from freezing. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the heat-sharing system of the liquefied gas system and the compressed air system described in Embodiment 1 of this utility model;

[0029] Figure 2 This is a schematic diagram of the heat exchanger in this utility model;

[0030] Figure 3 This is a schematic diagram of the heat-sharing system of the liquefied gas system and the compressed air system described in Embodiment 2 of this utility model;

[0031] In the diagram, 1 is the compressed air system, 2 is the liquefied petroleum gas system, and 3 is the heat exchanger.

[0032] 11 Air compressor, 12 Refrigerated dryer, 13 Compressed air storage tank, 14 Air condenser, 15 Compressed air buffer tank, 16 First oil separator, 17 Dryer, 18 Second oil separator;

[0033] 100 First input pipe, 200 First output pipe, 101 First valve, 201 Second valve;

[0034] 21 Liquefied gas storage tank, 22 Vaporizer, 23 Vaporized gas storage tank;

[0035] 300 Second input tube, 400 Second output tube, 301 Third valve, 401 Fourth valve;

[0036] 31 Refrigerant Channel, 32 Heat Channel;

[0037] 500 third input transistor, 600 third output transistor, 700 fourth input transistor, 800 fourth output transistor, 900 fifth output transistor, 1000 sixth output transistor;

[0038] 4. Control valve, 5. Output main valve, 6. Temperature sensor. Detailed Implementation

[0039] The technical solutions in the embodiments of this utility model will now be clearly and completely described in conjunction with the accompanying drawings.

[0040] Example 1

[0041] like Figure 1 As shown, a heat-sharing system for a liquefied gas system and an air compressor system includes an air compressor system 1, a liquefied gas system 2, and a heat exchanger 3.

[0042] The air compressor system 1 includes an air compressor 11, a refrigerated dryer 12, and a compressed air storage tank 13 connected in series. The refrigerated dryer 12 is provided with a first input pipe 100 and a first output pipe 200 at its two ends, respectively. A first valve 101 and a second valve 201 are respectively provided on the first input pipe 100 and the first input pipe 200. In this embodiment, the refrigerated dryer 12 is a variable frequency refrigerated dryer.

[0043] The liquefied gas system 2 includes an LPG storage tank 21, a vaporizer 22, and a vaporized gas storage tank 23 connected in series. The vaporizer 22 has a second input pipe 300 and a second output pipe 400 at its two ends, respectively. A third valve 301 and a fourth valve 401 are respectively installed on the second input pipe 300 and the second output pipe 400. The fourth valve 401 serves as a maintenance valve and a pressure maintaining valve, used to regulate the gas pressure entering the vaporized gas storage tank 23 to meet different usage requirements. Furthermore, during maintenance, the fourth valve 401 can disconnect the connection between the vaporizer 22 and the vaporized gas storage tank 23 to prevent backflow of vaporized gas.

[0044] In this embodiment, the vaporizer 22 is specifically an ambient air vaporizer. An ambient air vaporizer is a high-efficiency, environmentally friendly, and energy-saving heat exchange device that uses natural air convection to heat the low-temperature liquid in the heat exchange tube, causing it to completely evaporate into gas. It mainly uses the natural convection air in the atmosphere as a heat source, and the low-temperature liquid in the heat exchange tube is vaporized into a gas at a constant temperature.

[0045] The heat exchanger 3 is provided with a refrigerant channel 31 and a heat medium channel 32. The inlet of the refrigerant channel 31 is connected to the liquefied gas storage tank 21 through a third input pipe 500. The outlet of the refrigerant channel 31 is connected to the second input pipe 300 through a third output pipe 600. The connection between the third output pipe 600 and the second input pipe 300 is located on the outlet side of the third valve 301.

[0046] The inlet of the heat medium channel 32 is connected to the first inlet pipe 100 through the fourth inlet pipe 700, and the connection between the fourth inlet pipe 700 and the first inlet pipe 100 is located on the inlet side of the first valve 101.

[0047] The outlet of the heat medium channel 32 is connected to the first input pipe 100 through the fourth output pipe 800, and the connection between the fourth output pipe 800 and the first input pipe 100 is located on the outlet side of the first valve 101.

[0048] The outlet of the heat medium channel 32 is connected to the first output pipe 200 through the fifth output pipe 900, and the connection between the fifth output pipe 900 and the first output pipe 200 is located on the outlet side of the second valve 201.

[0049] Specifically, the heat exchanger 3 is a U-tube heat exchanger. The heat exchanger 3 is made of stainless steel.

[0050] Control valves 4 are installed on the third input pipe 500, the third output pipe 600, the fourth input pipe 700, the fourth output pipe 800, and the fifth output pipe 900.

[0051] The heat sharing system of the liquefied gas system and the compressed air system also includes an output main valve 5 located on the outlet side of the heat medium channel 32, and the fourth output pipe 800 and the fifth output pipe 900 are respectively connected to the outlet of the output main valve 5.

[0052] The compressed air system 1 also includes an air condenser 14 and a compressed air buffer tank 15 connected in sequence.

[0053] The air condenser 14 is connected to the air compressor 11, and the compressed air buffer tank 15 is connected to the refrigerated dryer 12.

[0054] The air compressor system 1 also includes a first oil separator 16 disposed between the air condenser 14 and the air compressor 11 and between the compressed air buffer tank 15 and the refrigerated dryer 12.

[0055] The compressed air system 1 also includes a dryer 17 disposed between the refrigerated dryer 12 and the compressed air storage tank 13. Specifically, the dryer 17 is a micro-heat regeneration adsorption dryer. A micro-heat regeneration adsorption dryer is a device that uses the adsorption effect of an adsorbent to dry compressed air through micro-heat regeneration technology.

[0056] The compressed air system 1 also includes a second oil separator 18 disposed between the refrigerated dryer 12 and the dryer 17 and between the dryer 17 and the compressed air storage tank 13.

[0057] The heat sharing system of the liquefied gas system and the compressed air system also includes a temperature sensor 6, which is disposed on the first output pipe 200 and located on the side away from the refrigerated dryer 12 at the connection between the fifth output pipe 900 and the first output pipe 200.

[0058] like Figure 1 and Figure 2 As shown, in this embodiment, air is compressed by air compressor 11 to produce high-temperature and high-pressure gas. After initial cooling by air condenser 14 and oil removal by first oil separator 16, it enters heat exchanger 3 for heat exchange and cooling. The shell side of the U-tube heat exchanger carries liquefied gas, while the tube side carries high-temperature compressed air. The liquefied gas in the shell side absorbs heat from the high-temperature compressed air in the tube side and vaporizes. At the same time, the temperature of the compressed air decreases. It then enters dryer 17 for drying and second oil separator 18 for further oil removal. Finally, it enters compressed gas storage tank 13 for storage, while the liquefied gas absorbs heat and vaporizes, entering vaporized gas storage tank 23 for storage, and then enters each user unit.

[0059] In this embodiment, when the liquefied petroleum gas (LPG) supply is insufficient, if the compressed air fails to reach the set temperature value after passing through the heat exchanger 3, the temperature sensor 6 collects the temperature of the compressed air in real time and feeds it back to the controller. The controller then adjusts the valve to allow the compressed air, which has been preliminarily cooled by the heat exchanger 3, to re-enter the refrigerated dryer 12, thus reducing the workload of the refrigerated dryer 12. The LPG that has passed through the heat exchanger 3 is not completely vaporized and continues to be sent to the vaporizer 22 for complete vaporization before being sent to the vaporized gas storage tank 23.

[0060] When the liquefied gas supply is sufficient, the liquefied gas enters the heat exchanger 3. When the compressed air temperature drops to the set value, the temperature of the compressed air is collected in real time by the temperature sensor 6 and fed back to the controller. The controller adjusts the valve, and the excess liquefied gas will enter the vaporizer 22 through the bypass pipeline, absorb heat, generate nitrogen, and enter the nitrogen storage tank 23.

[0061] This invention adds a U-tube heat exchanger and instrumentation control system between the liquefied gas system and the compressed air system, achieving complementary advantages between the two systems, reducing production costs, improving safety performance, and lowering the compressed air dew point temperature. This technology can be used to combine liquid nitrogen vaporization systems with compressed air systems, liquid oxygen vaporization systems with compressed air systems, and liquid argon vaporization systems with compressed air systems.

[0062] By utilizing heat exchangers to recover and reuse the cooling capacity of liquefied petroleum gas (LPG) and cool high-temperature compressed air, energy consumption and production costs of compressed air can be reduced. Furthermore, LPG cooling achieves a more effective condensation effect than refrigerated dryers, meeting the dew point requirements of compressed air. During the LPG vaporization process, the recovery of cooling capacity through high-temperature compressed air prevents the vaporizer from freezing and reduces the need for steam heating, thus lowering steam consumption. Connecting the heat exchanger and vaporizer in series further ensures the safety of the LPG vaporization process, preventing the introduction of low-temperature LPG into the storage tank due to large LPG usage, which could cause safety hazards such as low-temperature or vaporization expansion.

[0063] Example 2

[0064] like Figure 3 As shown, the difference from Embodiment 1 is that the heat sharing system of the liquefied gas system and the air compressor system further includes a sixth output pipe 1000. The outlet of the refrigerant channel 31 is connected to the gasified gas storage tank 23 through the sixth output pipe 1000. A control valve 4 is provided on the sixth output pipe 1000. The sixth output pipe 1000 is connected to the second output pipe 400 and the connection point along the fluid flow direction is located behind the fourth valve 401.

[0065] In this embodiment, when the liquefied petroleum gas (LPG) supply is insufficient, if the compressed air fails to reach the set temperature value after passing through the heat exchanger 3, the temperature sensor 6 collects the temperature of the compressed air in real time and feeds it back to the controller. The controller then adjusts the valve to allow the compressed air, which has been preliminarily cooled by the heat exchanger 3, to re-enter the refrigerated dryer 12, thus reducing the workload of the refrigerated dryer 12. After the LPG passes through the heat exchanger 3 and is completely vaporized, it directly enters the vaporized gas storage tank 23 through the sixth output pipe 1000.

Claims

1. A heat-sharing system for a liquefied gas system and an air compressor system, characterized in that: It includes an air compressor system (1), a liquefied gas system (2), and a heat exchanger (3); The air compressor system (1) includes an air compressor (11), a refrigerated dryer (12) and a compressed air storage tank (13) connected in series. The refrigerated dryer (12) is provided with a first input pipe (100) and a first output pipe (200) at both ends. A first valve (101) and a second valve (201) are provided on the first input pipe (100) and the first output pipe (200) respectively. The liquefied gas system (2) includes a liquefied gas storage tank (21), a vaporizer (22) and a vaporized gas storage tank (23) connected in series. The vaporizer (22) is provided with a second input pipe (300) and a second output pipe (400) at both ends. A third valve (301) is provided on the second input pipe (300). The heat exchanger (3) is provided with a refrigerant channel (31) and a heat medium channel (32). The inlet of the refrigerant channel (31) is connected to the liquefied gas storage tank (21) through a third input pipe (500). The outlet of the refrigerant channel (31) is connected to the second input pipe (300) through a third output pipe (600). The connection between the third output pipe (600) and the second input pipe (300) is located on the side of the outlet of the third valve (301). The inlet of the heat medium channel (32) is connected to the first inlet pipe (100) through the fourth inlet pipe (700), and the connection between the fourth inlet pipe (700) and the first inlet pipe (100) is located on the inlet side of the first valve (101); The outlet of the heat medium channel (32) is connected to the first input pipe (100) through the fourth output pipe (800), and the connection between the fourth output pipe (800) and the first input pipe (100) is located on the side of the outlet of the first valve (101); The outlet of the heat medium channel (32) is connected to the first outlet pipe (200) through the fifth outlet pipe (900), and the connection between the fifth outlet pipe (900) and the first outlet pipe (200) is located on the outlet side of the second valve (201); Control valves (4) are provided on the third input pipe (500), the third output pipe (600), the fourth input pipe (700), the fourth output pipe (800), and the fifth output pipe (900).

2. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1, characterized in that: It also includes a main output valve (5) located on the outlet side of the heat medium channel (32), wherein the fourth output pipe (800) and the fifth output pipe (900) are respectively connected to the outlet of the main output valve (5).

3. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1, characterized in that: The compressed air system (1) also includes an air condenser (14) and a compressed air buffer tank (15) connected in sequence; The air condenser (14) is connected to the air compressor (11), and the compressed air buffer tank (15) is connected to the refrigerated dryer (12).

4. The heat sharing system for the liquefied gas system and the compressed air system according to claim 3, characterized in that: The air compressor system (1) also includes a first oil separator (16) disposed between the air condenser (14) and the air compressor (11) and between the compressed air buffer tank (15) and the refrigerated dryer (12).

5. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1 or 4, characterized in that: The compressed air system (1) also includes a dryer (17) disposed between the refrigerated dryer (12) and the compressed air storage tank (13).

6. The heat sharing system for the liquefied gas system and the compressed air system according to claim 5, characterized in that: The compressed air system (1) also includes a second oil separator (18) disposed between the refrigerated dryer (12) and the dryer (17) and between the dryer (17) and the compressed air storage tank (13).

7. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1, characterized in that: It also includes a temperature sensor (6), which is disposed on the first output tube (200) and located on the side away from the refrigerated dryer (12) at the connection between the fifth output tube (900) and the first output tube (200).

8. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1, characterized in that: The heat exchanger (3) is a U-tube heat exchanger.

9. The heat sharing system for the liquefied gas system and the compressed air system according to claim 1 or 8, characterized in that: The heat exchanger (3) is made of stainless steel.

10. The heat-sharing system for the liquefied gas system and the compressed air system according to claim 1, characterized in that: It also includes a sixth output pipe (1000), the outlet of the refrigerant channel (31) is connected to the gasification gas storage tank (23) through the sixth output pipe (1000), and a control valve (4) is provided on the sixth output pipe (1000).

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