JP4493806B2 - Liquid gas delivery equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates Bei liquid delivery set of the liquefied gas, particularly, when the up or feeding a liquefied gas using a compression means such as a pump, effectively prevents the cavity over station due to vaporization of the liquefied gas liquefaction feeding of the liquefied gas that can be feeding a gas-liquid setting Bei relates.
[0002]
[Prior art]
When liquid such as water or oil is sent, a return pipe (return water pipe) is provided to return the liquid from the compressor secondary side to the compressor primary side in order to adjust the liquid feed flow rate in the compressor (pump). It is generally performed to adjust the amount of supply liquid by adjusting the flow rate adjusting valve provided in the return pipe.
[0003]
[Problems to be solved by the invention]
However, in the conventional method, when trying to pressurize and send a liquid that easily vaporizes, such as liquefied gas, heat intrusion from the compressor primary side pipe, heat conduction from the compressor drive unit, and fluid itself A part of the liquefied gas is vaporized by the compression heat or the like, and furthermore, the compressor causes cavitation due to the vaporized gas, and there is a possibility that liquid feeding becomes impossible or the compressor itself is damaged.
[0004]
The present invention aims to provide a liquid feed equipment of liquefied vaporized prevent cavity over station by the gas, efficiently compressed and liquid feed-rate control of the liquefied gas can be liquefied gas during feeding It is said.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the first configuration of the liquefied gas delivery system of the present invention is a gas return pipe for returning a part of the compressed gas from the secondary pipe to the primary pipe of the compression means for compressing the liquefied gas. And a pressure holding valve for controlling the return amount of the compressed gas and a cooling means for cooling the compressed gas are provided in the gas return pipe.
[0006]
The second configuration of the liquefied gas delivery system according to the present invention includes a gas return pipe for returning the compressed gas from the secondary side pipe of the compression means for compressing the liquefied gas to the primary side pipe, and the compressed gas is provided in the gas return pipe. A pressure holding valve for controlling the return amount of the compressor is provided, and a cooling means for cooling the liquefied gas after joining the compressed gas is provided between the connecting point of the gas return pipe in the compressor primary side pipe and the compression means. It is characterized by.
[0007]
The liquefied gas to be compressed is derived from a liquefied gas storage tank, the cooling means uses a chill of the liquefied gas in the liquefied gas storage tank as a cooling source, and the cooling means is a refrigerant of a refrigerator. Is used as a cooling source .
[0008]
Further, the present invention is characterized in that the liquefied gas to be compressed is derived from an air separation device, and a liquefied gas storage tank is provided at a destination of the compressed gas .
[0009]
Furthermore, the present invention is characterized in that before Symbol compression means is a gas-driven.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system diagram showing a first embodiment of the liquefied gas delivery system of the present invention. This liquefied gas supply facility is a facility for boosting a liquefied gas stored in the low-pressure liquefied gas storage tank 11, for example, liquefied carbon dioxide gas by a compressor (pump) 12 and sending it to the high-pressure liquefied gas storage tank 13. . An accumulator 14 and a pressure gauge (PT) 15 for absorbing pressure fluctuation are provided on the secondary side of the compressor 12, and the high-pressure liquefied gas storage tank 13 detects the amount of liquefied carbon dioxide in the storage tank. As an apparatus that uses the pressure-increased liquefied carbon dioxide, for example, a dry ice generating device, a cleaning device, a purifying device, or a liquefied carbon dioxide using device 17 that appropriately combines them is used. Is provided.
[0011]
Furthermore, in this embodiment, an inverter 18 is provided for controlling the operating state of the compressor 12 via an electric motor that is a drive source of the compressor 12 by signals from the pressure gauge 15 and the differential pressure gauge 16. ing.
[0012]
A gas return pipe for returning a part of the compressed gas (compressed liquefied gas and vaporized gas) from the secondary side pipe 19 of the compressor 12 to the primary side pipe 20 is provided to the compressor 12 as the compression means. 21 is provided, and the gas return pipe 21 includes a pressure holding valve 22 which is a control means for controlling the return amount (recirculation amount) of the compressed gas, and a heat exchanger 23 which is a cooling means for cooling the compressed gas. Is provided.
[0013]
The liquefied carbon dioxide gas stored in the low-pressure liquefied gas storage tank 11 is sent to the compressor 12 through the primary side pipe 20. When the operation of the compressor 12 starts, the compressor 12 starts to compress and feed the liquefied carbon dioxide gas, and the liquefied carbon dioxide gas having a predetermined pressure starts to be stored in the high-pressure liquefied gas storage tank 13. At this time, when the pressure in the secondary side pipe 19 of the compressor 12 becomes equal to or higher than a predetermined pressure, that is, the pressure of the liquefied gas compressed by the compressor 12 is the set pressure of the pressure holding valve 22 provided in the gas return pipe 21. When the pressure is reached, the pressure holding valve 22 is opened, and the liquefied carbon dioxide gas containing the vaporized carbon dioxide gas is introduced into the heat exchanger 23 through the gas return pipe 21, and the predetermined temperature is applied by the cooling medium supplied to the heat exchanger 23. The carbon dioxide gas that has been cooled and vaporized is re-liquefied and re-supplied to the primary side pipe 20 of the compressor 12.
[0014]
When the high-pressure liquefied gas storage tank 13 becomes full, the differential pressure gauge 16 detects a full state, and the inverter 18 starts a reduction operation of the compressor 12. Also at this time, when the pressure of the secondary side pipe 19 of the compressor 12 becomes equal to or higher than the set pressure of the pressure keeping valve 22, liquefied carbon dioxide gas including vaporized carbon dioxide gas is introduced into the heat exchanger 23 through the gas return pipe 21. The carbon dioxide gas that has been cooled to a predetermined temperature and vaporized is liquefied, and then re-supplied to the primary side pipe 20 of the compressor 12.
[0015]
That is, when a part of the compressed gas is returned from the secondary side to the primary side of the compressor 12 to perform flow rate adjustment or pressure adjustment, the compressed gas refluxed to the primary side is introduced into the heat exchanger 23 and cooled, By condensing carbon dioxide gas (vaporized gas) contained in the compressed gas and returning to the primary side after cooling down to a predetermined temperature, heat intrusion from each part, heat conduction from the pump drive part, liquefied carbon dioxide gas itself Even when the liquefied carbon dioxide gas is vaporized by compression heat or the like, it is possible to prevent the compressor 12 from causing cavitation due to the vaporized gas.
[0016]
The compressor (compression means) 12 may be any type of pump such as a centrifugal type, an axial flow type, or a reciprocating type. Moreover, although the rotation control of the electric motor by the inverter 18 was used as the control means of the compressor 12, other electrical control means such as resistance control can be used. Further, although the pressure holding valve 22 is used as the control means provided in the gas return pipe 21, a throttle portion capable of adjusting the flow rate such as a needle valve may be used.
[0017]
Further, the liquefied gas to be sent is usually derived from the liquefied gas storage tank, but may be derived from other equipment such as an air separation device. The kind of liquefied gas is also arbitrary, and for example, it can be applied to liquefied oxygen, liquefied nitrogen, liquefied argon, liquefied natural gas, liquefied hydrogen and the like in addition to the liquefied carbon dioxide gas. In addition, the destination of the liquefied gas after compression is arbitrary. Also, the cooling means (heat exchanger) provided in the gas return pipe 21 may be any means that acts as a condenser for condensing and liquefying the vaporized gas and can cool the gas returning to the primary side to a predetermined temperature. Any suitable one can be used as long as it can condense the liquefied gas to be sent, for example, it may be a refrigerant such as ammonia or flon cooled by a refrigerator, or other appropriate low-temperature refrigerant, for example, liquefaction. When the gas is the liquefied carbon dioxide gas, liquefied nitrogen, cryogenic nitrogen gas, or the like can be used, and the coldness of the liquefied gas in the liquefied gas storage tanks 11 and 13 can also be used.
[0018]
FIG. 2 is a system diagram showing a second embodiment of the present invention. This liquefied gas supply facility uses a rectifying unit 24 constituted by a spiral pipe in place of the high-pressure liquefied gas storage tank 13 in the first embodiment. In addition, the same code | symbol is attached | subjected to the component same as the component of the said 1st form example, and detailed description is abbreviate | omitted.
[0019]
Also in the present embodiment, similarly to the first embodiment, the vaporized gas is condensed and cooled to a predetermined temperature by cooling the compressed gas refluxed from the secondary side to the primary side of the compressor 12 by the heat exchanger 23. Therefore, the occurrence of cavitation in the compressor 12 can be prevented.
[0020]
FIG. 3 is a system diagram showing a first reference example. In the liquefied gas delivery system shown in this reference example, the secondary side piping of the compressor 12 is used instead of the gas return piping 21 that connects the compressor secondary side piping 19 and the primary side piping 20 in the first embodiment. The low pressure liquefied gas storage tank 19 is provided with a gas return pipe 31 for recirculating the compressed gas through a pressure holding valve 32 as a control means. In addition, the same code | symbol is attached | subjected to the component same as the component of the said 1st form example, and detailed description is abbreviate | omitted.
[0021]
That is, when the inside of the secondary side pipe 19 of the compressor 12 becomes equal to or higher than the set pressure of the pressure holding valve 32 provided in the gas return pipe 31, a part of the liquefied carbon dioxide gas including the vaporized carbon dioxide gas is converted into the secondary side pipe 19. Is returned to the low-pressure liquefied gas storage tank 11 through the gas return pipe 31. Therefore, the vaporized gas is returned to the low-pressure liquefied gas storage tank 11 without being sucked into the compressor 12 and is directly cooled and reliquefied by the liquefied carbon dioxide gas in the low-pressure liquefied gas storage tank 11. Can prevent cavitation from occurring.
[0022]
FIG. 4 is a system diagram showing a third embodiment of the present invention. In the liquefied gas delivery system shown in this embodiment, an air-driven turbine is used as the drive source of the compressor 12 instead of the electric motor. In addition, the same code | symbol is attached | subjected to the component same as the component of the said 2nd example, and detailed description is abbreviate | omitted.
[0023]
That is, in this embodiment, driving air having a predetermined pressure is supplied from the driving air pipe 33, and the opening degree of the flow control valve 34 provided in the driving air pipe 33 is determined from the signals from the pressure gauge 15 and the differential pressure gauge 16. The liquid feed flow rate of the compressor 12 is controlled by adjusting the flow rate of the drive air supplied to the turbine for driving the compressor by adjusting with the electric actuator (M) 35 operated by the above. As a driving gas for the compressor driving turbine, various gases such as nitrogen gas, carbon dioxide, and argon gas can be used as the driving gas in addition to the air (compressed air).
[0024]
FIG. 5 is a system diagram showing a fourth embodiment of the present invention. In the liquefied gas supply facility shown in this embodiment, a gas return pipe 36 for returning a part of the compressed gas from the secondary side pipe 19 of the compressor 12 to the primary side pipe 20 is provided, and the gas return pipe 36 is provided with the gas return pipe 36. A heat exchanger that is provided with a pressure holding valve 37 as a control means, and further condenses the vaporized gas in the primary side pipe 20 between the connection point 38 of the gas return pipe 36 and the compressor 12 and cools it to a predetermined temperature. 39 is provided. In addition, the same code | symbol is attached | subjected to the component same as the component of the said 1st form example, and detailed description is abbreviate | omitted.
[0025]
Therefore, in this embodiment, the compressed gas returned from the secondary side pipe 19 to the compressor primary side merges with the liquefied carbon dioxide gas from the low-pressure liquefied gas storage tank 11 and then flows into the heat exchanger 39, The vaporized gas contained in is reliquefied. By providing the heat exchanger 39 in the path after the compressed gas joining in this way, it becomes possible to make the degree of supercooling of the liquefied carbon dioxide gas flowing into the compressor 12 constant. It will be in a stable state.
[0026]
FIG. 6 is a system diagram showing a second reference example. In the liquefied gas delivery facility shown in the present reference example, gas-liquid separation means 40 is provided in the secondary side pipe 19 of the compressor 12 in the first reference example to actively separate the vaporized gas in the compressed gas and separate it. Only the vaporized gas is returned from the gas return pipe 31 to the low-pressure liquefied gas storage tank 11. Thereby, the liquefied gas in the state which hardly contains vaporized gas can be sent to the high pressure liquefied gas storage tank 13 grade | etc.,. In addition, the same code | symbol is attached | subjected to the component same as the component of the said 1st reference example, and detailed description is abbreviate | omitted.
[0027]
At this time, the vaporized gas to be refluxed may be cooled by the heat exchanger 23 as in the first embodiment and returned to the primary side pipe 20, or the primary side provided with the heat exchanger 39 as in the fourth embodiment. You may make it return to the heat exchanger upstream of the piping 20. FIG. The gas-liquid separation means 40 may be a general gas-liquid separator, but the high-pressure liquefied gas storage tank 13 is used as the gas-liquid separation means, and a gas return pipe is connected to the upper part of the storage tank 13. You can also.
[0028]
【Example】
Example 1
Using the liquid feeding equipment having the configuration shown in FIG. 2, liquefied carbon dioxide gas having a pressure of 2 MPa and a temperature of about −20 ° C. was fed to the dry ice generator at a flow rate of about 1.3 kg / min. A reciprocating compressor made by Tama Seiki was used as the compressor, and a Mitsubishi Electric refrigerator was used as the heat exchanger (condenser). While the dry ice generator continuously operated to generate dry ice, there was no abnormal noise in the compressor, abnormal vibration, temperature rise, compressor damage, etc. In addition, stable operation was possible.
[0029]
Example 2
2 is used, and liquefied carbon dioxide gas at a pressure of 2 MPa and a temperature of about −20 ° C. is sent to a liquefied carbon dioxide gas purifier at a flow rate of about 1.0 kg / min. Carbon dioxide was supplied to the dry ice snow cleaning device. The compressor used was a Haskell diaphragm compressor, and the heat exchanger (condenser) was a Mitsubishi Electric refrigerator. Although the dry ice snow cleaning device was operated continuously, there was no abnormal noise in the compressor, abnormal vibration, temperature rise, compressor damage, etc., and stable operation including flow rate control was possible. .
[0030]
【The invention's effect】
As described above, according to the present invention, it is possible to feed liquefied gas in a stable state by preventing the occurrence of cavitation due to vaporized gas, and improve the operation efficiency and controllability of the liquefied gas feed equipment. Etc.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a first embodiment of a liquefied gas delivery system according to the present invention.
FIG. 2 is a system diagram showing a second embodiment of the liquefied gas delivery system of the present invention.
FIG. 3 is a system diagram showing a first reference example.
FIG. 4 is a system diagram showing a third embodiment of the liquefied gas delivery system of the present invention.
FIG. 5 is a system diagram showing a fourth embodiment of the liquefied gas delivery facility of the present invention.
FIG. 6 is a system diagram showing a second reference example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Low pressure liquefied gas storage tank, 12 ... Compressor, 13 ... High pressure liquefied gas storage tank, 14 ... Accumulator, 15 ... Pressure gauge, 16 ... Differential pressure gauge, 17 ... Liquefied carbon dioxide use apparatus, 18 ... Inverter, 19 ... Secondary side piping 20 ... primary pipe, 21 ... gas return pipe, 22 ... minimum pressure valve, 23 ... heat exchanger, 24 ... rectifying unit, 3 3 ... air pipe drive, 34 ... flow control valve, 35 ... electric actuator, 36 ... Gas return pipe, 37 ... Pressure holding valve, 38 ... Connection

Claims (8)

A gas return pipe for returning a part of the compressed gas from the secondary side pipe of the compression means for compressing the liquefied gas to the primary side pipe is provided, and a pressure holding valve for controlling the return amount of the compressed gas is provided in the gas return pipe, and the compression A liquefied gas liquid supply facility comprising a cooling means for cooling the gas. A gas return pipe for returning the compressed gas from the secondary side pipe of the compression means for compressing the liquefied gas to the primary side pipe is provided, a pressure holding valve for controlling the return amount of the compressed gas is provided in the gas return pipe, and the compressor primary side A liquefied gas feeding facility characterized in that a cooling means for cooling the liquefied gas after merging the compressed gases is provided between a connection point of the gas return pipe in the pipe and the compressing means.   The liquefied gas feeding equipment according to claim 1 or 2, wherein the compressed liquefied gas is derived from a liquefied gas storage tank.   4. The liquefied gas liquid feeding equipment according to claim 3, wherein the cooling means uses, as a cooling source, coldness of the liquefied gas in the liquefied gas storage tank.   The liquefied gas liquid feeding equipment according to claim 1, wherein the cooling means uses a refrigerant of a refrigerator as a cooling source.   The liquefied gas feeding equipment according to claim 1 or 2, wherein the compressed liquefied gas is derived from an air separation device.   The liquefied gas supply facility according to claim 1 or 2, wherein a liquefied gas storage tank is provided at a delivery destination of the compressed gas.   3. The liquefied gas delivery system according to claim 1, wherein the compression means is a gas drive type.

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