JP3191161B2 - Cooling water cooling method and apparatus for air liquefaction / separation apparatus utilizing refrigeration of liquefied natural gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to liquefied natural gas (LN).
The present invention relates to a method and an apparatus for cooling water of an air liquefaction / separation apparatus utilizing cold of G).

[0002]

2. Description of the Related Art FIG. 3 shows an example of an air liquefaction / separation apparatus utilizing the cold of LNG. In this air liquefaction / separation apparatus, the raw material air pressurized by the raw material air compressor 1 is brought into direct contact with, for example, chiller water obtained by a CFC refrigerator in a washing cooling tower 2 and cooled to around 5 ° C. It is refined and cooled to near the liquefaction point in the main heat exchanger 4 and introduced into the rectification column 5 to perform a well-known liquefaction and rectification separation, and liquefied oxygen LO, liquefied nitrogen LN, nitrogen gas GN, etc. are collected as products. Things
In order to replenish the cold required for operation of the apparatus, a circulating nitrogen system 6 utilizing the cold of LNG is provided.

[0003] In the circulating nitrogen system 6, first, a part of the nitrogen gas led out from the upper part of the lower tower of the rectification column by the conduit 7 is introduced into the main heat exchanger 4 through the conduit 8, and After being cooled by the first cooler 9, it is sucked into the low-pressure stage 10 of the nitrogen compressor. The nitrogen gas branched from the conduit 7 to the conduit 11 is supplied to the subcooler 1
2, after being sequentially introduced into the first heat exchanger 13 and the second heat exchanger 14, they are combined with the nitrogen gas branched into the conduit 8 and sucked into the low-pressure stage 10 of the nitrogen compressor.

[0004] The nitrogen gas compressed in the low-pressure stage 10 of the nitrogen compressor is cooled in a second cooler 15 and then further compressed in a high-pressure stage 16 of the nitrogen compressor. High pressure stage 16
A portion of the nitrogen gas, which has become high pressure in the second heat exchanger 14,
Cooled by the first heat exchanger 13 and flushed into the gas-liquid separator 18 via the valve 17. The remainder of the high-pressure nitrogen gas is introduced into the first LNG heat exchanger 20 from the conduit 19, exchanges heat with the LNG from the conduit 21 to collect the cold of the LNG, and then joins the nitrogen gas. First heat exchanger 1
3. Flush into the gas-liquid separator 18 via the valve 17.

The uncondensed nitrogen gas in the gas-liquid separator 18 is
After being led out to the conduit 22 and sequentially introduced into the first heat exchanger 13 and the second heat exchanger 14, it joins the nitrogen gas sucked into the high-pressure stage 16 of the nitrogen compressor and circulates through the system. . On the other hand, the liquefied nitrogen in the gas-liquid separator 18 is led out to the conduit 23, passes through the subcooler 12, expands to the pressure of the lower column of the rectification column by the valve 24, and circulates to the upper portion of the column.

The first cooler 9 and the second cooler 15 are
A cooling circuit using an appropriate refrigerant, for example, Freon, is formed.
The NG heat exchanger 26 exchanges heat with LNG for cooling, and uses the refrigerant as a cooling source to cool the first cooler 9 and the second cooler 15.
To cool the nitrogen gas.

On the other hand, the first LNG heat exchanger 20 and the second LNG heat exchanger 26, which are liquefied natural gas heat exchange means ,
The natural gas that has been partially recovered from the cold and vaporized and led to the conduit 27 is further heated by the atmosphere, seawater, or the like, and is supplied to a demand destination as a gas having a predetermined temperature and pressure.

[0008]

Therefore, in the conventional air liquefaction / separation apparatus, the refrigeration held by LNG is reduced to the atmosphere,
It is discharged into seawater and the like, and it cannot be said that the cold is fully utilized, while a cooling source such as a CFC refrigerator is required. That is, the conventional air liquefaction / separation apparatus using the cold of LNG uses a large amount of LNG and uses a low temperature range of about -150 ° C. because the liquefaction temperature of the air component is lower than the vaporization temperature of LNG. It is often planned to reduce its power consumption. In this case, -9 from the heat balance
LNG refrigeration at about 0 ° C. or higher is excessive and is released to the atmosphere, seawater, and the like as described above.

On the other hand, when adsorbing and removing carbon dioxide and water as impurities in the raw material air, it is necessary to precool the adsorption temperature to 5 to 15 ° C. As a method for pre-cooling the raw material air, a method of directly cooling by exchanging heat with Freon in a Freon refrigerator or introducing chiller water of 5 to 10 ° C. and raw material air into a washing cooling tower (filling tower, etc.) There is a method in which both are directly heat-exchanged, and a method in which chiller water and raw air are indirectly heat-exchanged with a heat exchanger.

Accordingly, an object of the present invention is to provide a cooling water cooling method and apparatus for an air liquefaction / separation apparatus that effectively utilizes the coldness of LNG as a cooling source for the air liquefaction / separation apparatus.

[0011]

In order to achieve the above-mentioned object, a cooling water cooling method for an air liquefaction / separation apparatus utilizing the cooling of LNG according to the present invention comprises cooling each part of the air liquefaction / separation apparatus.
Cooling means for cooling by cooling water, and air cooling of the cooling water
Before the air-cooled cooling tower, the air-cooled cooling tower and the cooling means.
Cooling with a cooling water circulation system for circulating the cooling water
In the method for cooling the cooling water of the water cooling equipment, the method includes the step of heat-exchanging the nitrogen gas and the liquefied natural gas of the air liquefaction / separation device to collect a part of the cold and thereby cooling the vaporized low-temperature natural gas.
Refrigeration and recovering the cold natural gas by Rukoto the allowed cooling water heat exchanger before means introducing warming, the recovered refrigeration
This cools the cooling water before introducing the cooling means . Also installed in the air liquefaction separation device
Heat exchange with the low-temperature natural gas
The cold water is collected by cooling and cooled, and the cooling water is introduced.
The raw material is brought into direct contact with the compressed raw material air
Characterized by cooling the compressed raw material air, further comprising:
Compressor intercooler installed in air liquefaction separation unit
-And / or after-cooler
Cold recovery by heat exchange of water and introduction of cooled cooling water
And indirect heat exchange with the gas compressed by the compressor
Gas is cooled, and the low-temperature natural gas is cooled.
The amount and temperature of the cooling water that exchanges heat with the heat
The cooling of the cooling water circulation system according to the air temperature and water temperature
Adjusting the flow rate of water, further comprising:
Heats the cooling water in the cooling water circulation system according to the temperature and water temperature.
It is characterized by that .

[0012] Further, the cooling water cooling device of the air liquefaction / separation device utilizing the cold of LNG according to the present invention is an air liquefaction / separation device.
Cooling means for cooling each part of the cooling water with cooling water;
An air-cooled cooling tower for air-cooling the air-cooled cooling tower and the cooling
Means and a cooling water circulation system for circulating the cooling water.
Equipment for cooling the cooling water of the cooling water cooling equipment provided
To separate nitrogen gas and liquefied natural gas from the air liquefaction and separation unit.
A liquefied natural gas heat exchanger that recovers part of the cold through heat exchange
And the liquefied natural gas heat exchange means to recover some of the cold
Low-temperature natural gas vaporized by
The low-temperature natural gas is heated by exchanging heat with cooling water to cool the natural gas.
The cold is collected by the collected cold and the cooling
A low-temperature natural gas heater for cooling the cooling water before the stage introduction;
It is characterized by comprising a. In addition, the air liquefied component
The separation device recovers cold by heat exchange with the low-temperature natural gas.
Introduce cooling water that has been cooled and directly contact compressed air.
A washing cooling tower is installed to cool the compressed raw material air by touching it.
Characterized in that the air liquefaction separation device
The compressor is cooled by heat exchange with the low-temperature natural gas.
The cooling water that has been collected and cooled is introduced and compressed by the compressor.
To cool the gas by indirect heat exchange with the gas
-A cooler and / or aftercooler is installed
Characterized in that, the low-temperature natural gas heater,
Part of the cooling water derived from the heater is introduced into the heater.
Provided with a direct return line and a valve for adjusting the return amount
Wherein the cooling water circulation system further comprises:
A part of the cooling water derived from the air-cooled cooling tower is
Introduce directly into the cooling means, bypassing the natural gas heater
It has a conduit and a valve that regulates the flow rate.
And the cooling water circulation system includes the low-temperature natural gas.
A heater for heating the cooling water is provided upstream of the heater.
Wherein the cooling water circulation system further comprises:
The cooling water is bypassed to the heater, bypassing the air-cooled cooling tower.
A bypass pipe to be introduced and a valve to regulate the flow rate are provided
And the cooling water circulation system is
A bypass pipe to bypass the heater and a valve to regulate the flow rate
It is characterized by being provided. And the device of the present invention
Is a cooling device for cooling water that cools each part of the air liquefaction separation device.
Wherein the air liquefaction and separation device is a raw material air compressor.
A washing cooling tower for washing and cooling the raw material air, and nitrogen
Heat exchange between gas and liquefied natural gas
Liquefied natural gas heat exchange means to recover part of the cold
A circulating nitrogen system, wherein the cooling device is configured to liquefy the air.
Cooling means for cooling each part of the separation device with cooling water;
An air-cooled cooling tower that air-cools the cooling water,
Cooling water circulation for circulating the cooling water to the cooling means
And the cooling water circulation system includes the liquefied natural gas.
Low-temperature heaven that has been partially vaporized by heat exchange
Heat exchange between the natural gas and the cooling water before introducing the cooling means.
To recover the cold by heating the low-temperature natural gas.
The cooling before the cooling means is introduced by the collected cold
A low-temperature natural gas heater for cooling water;
A heater provided upstream of the heater to heat the cooling water
And adjust the bypass pipe and the flow rate that bypass the heater
A valve and bypassing the air-cooled cooling tower to the heater.
Equipped with a bypass pipe for introducing drainage water and a valve for adjusting the flow rate
It is also characterized by that .

[0013]

[Work] L exchanged heat with nitrogen gas in air liquefaction separation unit
Although NG rises in temperature to -100 ° C. or higher, it still has enough cooling to cool the cooling water. Therefore, by exchanging heat with this low-temperature natural gas with the cooling water, the cooling of LNG is reduced. It can be used effectively and a cooling source such as a CFC refrigerator for cooling water can be omitted.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 1, the cooling water cooling system 30 of the cryogenic air separation unit, the Figure 3 washing tower 2 in an air separation plant illustrated in, the feed air compressor 1 aftercooler or intercooler 1a or various compressor, A system for cooling the cooling water used in the cooling means such as the cooler 31 to a predetermined temperature and circulating the cooling water is provided. As a device for cooling the cooling water, the first LNG heat exchange in FIG. Low-temperature natural gas warmer 32 for exchanging heat between the low-temperature natural gas introduced into the conduit 27 and the cooling water by vaporization in the heat exchanger 20 and the second LNG heat exchanger 26, and cooling the cooling water by air. An air-cooled cooling tower 33 is provided.

The low-temperature natural gas heater 32 exchanges heat between nitrogen gas and LNG of the air liquefaction / separation apparatus as described above, and heat-exchanges low-temperature natural gas from which a part of the cold has been recovered with cooling water. Thus, the remaining cold of the LNG is used as cold for cooling the cooling water. This makes it possible to recover most of the cold of LNG by heat exchange with nitrogen gas and heat exchange with cooling water.

Hereinafter, the movement of the cooling water in the cooling water cooling equipment 30 will be described separately for summer (water temperature at the outlet of the air-cooled cooling tower 33: 30 ° C.) and winter (atmospheric temperature: 0 ° C., relative humidity: 25%).

Summertime First, in the low-temperature natural gas heater 32, 500 t / h
Cooling water exchanges heat with low-temperature natural gas at about -90 ° C.
C. and is pumped through a conduit 34 to a conduit 36 by a pump 35. Of the cooling water, 325 t / h is branched to a conduit 37, reaches a conduit 39 via a valve 38, and is returned to the low-temperature natural gas heater 32. 18t / h of cooling water is
From the conduit 36, it is branched to the conduit 40 and supplied to the rinsing cooling tower 2. The raw air GA is pre-cooled, and the temperature thereof is raised to 26.7 ° C., and the conduit 39 is passed through the conduit 41, the pump 42, and the conduit 43. As a result, it is returned to the low-temperature natural gas heater 32.

Another 150 t / h of the cooling water is branched into a conduit 44 and supplied to the cooler 31 of the compressor.
The temperature rises to 12 ° C., and is returned from the conduit 45 to the low-temperature natural gas heater 32 via the conduit 39. Further, another portion 7 t / h of the cooling water passes from the conduit 36 through the valve 46 and from the air-cooled cooling tower 33 to the conduit 47, the pump 48 and the conduit 4.
9, 30 sent via conduit 50, valve 51, conduit 52
1 t / h, 30 ° C cooling water and conduit 53 are combined, and 308 t / h,
It becomes 29.4 ° C. and is supplied to the aftercooler or intercooler 1a. Here, the cooling water heated to 40.7 ° C. is introduced into the air-cooled cooling tower 33 via the conduit 54, and is cooled to 30 ° C. by exchanging heat with the atmosphere.

The cooling water led from the air-cooled cooling tower 33 to the conduit 47 passes through the pump 48 and the conduit 49, and a part of the cooling water is supplied to the low-temperature natural gas heater 32 through a valve 55 at 7 t / h. It is introduced into a conduit 39 leading to it. Also, the remaining part 301
t / h circulates through the path from conduit 50 as described above.

The conduit 39 has 325 t / h of cooling water at 5 ° C. from the conduit 37 and the valve 38, and 18 t / h, 2 from the conduit 43.
6.7 ° C. cooling water, 150 t / h from pipe 45, 12 ° C. cooling water, 7 t / h from pipe 49 and valve 55, 30 ° C. cooling water are combined, and 500 t / h, 8.3 ° C. And returns to the low-temperature natural gas heater 32.

Winter In the low-temperature natural gas heater 32, as described above,
The cooling water of 0 t / h is cooled to 5 ° C. by exchanging heat with the low temperature natural gas at about −90 ° C., and is sent to the conduit 36 by the pump 35 through the conduit 34. Of the cooling water, 282 t / h is branched to a conduit 37, reaches a conduit 39 via a valve 38, and is returned to the low-temperature natural gas heater 32. 18 tons of cooling water
h is branched from a conduit 36 to a conduit 40 and supplied to the rinsing cooling tower 2, where the raw material air GA is pre-cooled, and the raw material air GA is cooled to 11.1.
The temperature is raised to 0 ° C., and is returned to the low-temperature natural gas heater 32 through the conduit 39 via the conduit 41, the pump 42, and the conduit 43.

Another 150 t / h of the cooling water is branched into a conduit 44 and supplied to the cooler 31 of the compressor.
The temperature rises to 12 ° C., and is returned from the conduit 45 to the low-temperature natural gas heater 32 via the conduit 39. Further, another 50 t / h of the cooling water passes from the conduit 36 through the valve 46 and from the air-cooled cooling tower 33 to the conduit 47, the pump 48, and the conduit 4.
9, 25 sent via conduit 50, valve 51, conduit 52
8t / h, 14.9 ° C cooling water and conduit 53
t / h, 13.3 ° C., and is supplied to the aftercooler or intercooler 1a. Here, the cooling water heated to 24.6 ° C. is introduced into the air-cooled cooling tower 33 via the conduit 54, and is cooled to 14.9 ° C. by heat exchange with the atmosphere.

The cooling water guided from the air-cooled cooling tower 33 to the conduit 47 passes through the pump 48 and the conduit 49, and a part of the cooling water is supplied to the low-temperature natural gas heater 32 through a valve 55 at 50 t / h. It is introduced into a conduit 39 leading to it. The remaining 25
8 t / h circulates in the path from conduit 50 as described above.

The conduit 39 has 282 t / h of cooling water at 5 ° C. from the conduit 37 and the valve 38, and 18 t / h, 1 from the conduit 43.
The cooling water at 1.1 ° C., the cooling water at 150 t / h from the conduit 45, the cooling water at 12 ° C., the cooling water at 50 t / h from the conduit 49 and the valve 55, and the cooling water at 14.9 ° C. are combined to form 500 t / h, 8. The cooling water becomes 3 ° C. and returns to the low-temperature natural gas heater 32.

As described above, by adjusting the flow rate of each part in summer and winter when the temperature and water temperature are different, the amount and temperature of the cooling water supplied to the low-temperature natural gas heater 32 can be made the same, and the low-temperature natural gas can be cooled. The amount of heat transfer in the heater 32, that is, the amount of cold collected by the low-temperature natural gas after the heat exchange between the process gas and LNG and a part of the cold collected can be kept substantially constant throughout the year. .

Therefore, the surplus refrigeration of the conventionally released LNG can be efficiently recovered. In addition, thereby, the raw material air introduced into the adsorber can be sufficiently cooled to improve the adsorption efficiency, and the compression efficiency of the compressor can be improved to reduce power consumption. Further, cooling equipment such as a CFC refrigerator used conventionally can be omitted, and the power cost can be reduced accordingly. in addition,
The temperature of the low-temperature natural gas derived from the low-temperature natural gas heater 32 can be kept constant irrespective of the air temperature or the water temperature (seawater temperature).

Next, FIG. 2 shows an example in which a configuration taking into account the prevention of freezing of cooling water in winter is added. That is, in the cooling water cooling device shown in FIG. 2, the heater 60 is installed so as to correspond to the air cooling type cooling tower 33 of the cooling water cooling device 30 shown in FIG. 1, and the heater 60 and the air cooling type cooling tower are provided. In addition to providing bypass pipes 61, 62, 63 for bypassing 33,
The aftercooler and the intercooler 1a, 1b of the raw material air compressor are provided with bypass pipes 64, and further provided with valves for adjusting the respective bypass flow rates. The same components as those of the cooling water cooling device 30 are denoted by the same reference numerals, and detailed description is omitted.

First, in a normal use state, the valve 60a of the heater 60 and the valve 61a of the bypass pipe 61 are closed,
The valve 62a of the bypass pipe 62 and the valve 63 of the bypass pipe 63
Open a. As a result, the cooling water is supplied to the air-cooled cooling tower 33 from the conduit 54, exchanges heat with the atmosphere, and is cooled to a predetermined temperature, and then the conduit 47, the bypass pipe 62, and the bypass pipe 6 are cooled.
3, circulating through the pump 48 and the conduit 49 in the same manner as described above.

Further, the ambient temperature drops, the temperature rise of the cooling water in each cooling section decreases, and the cooling capacity of the cooling water in the low-temperature natural gas heater 32 becomes excessive. If there is a possibility that the cooling water will freeze,
The valve 46 and the valves 64a and 64b of the bypass pipe 64 are opened appropriately, and the cooling water cooled by the low-temperature natural gas heater 32 is
It is supplied to the air-cooled cooling tower 33 or the heater 60. At this time, if the temperature of the water supplied to the air-cooled cooling tower 33 is lower than the ambient temperature, the cooling water is heated by the atmosphere. By opening the valve 46, the amount of cooling water supplied to the aftercooler and the intercoolers 1a and 1b increases. Keep the amount of cooling water supplied to the tank moderate.

The atmospheric temperature further decreases, and the air-cooled cooling tower 33
If it is necessary to bypass the valve, the valves 54a and 47a may be closed and the valves 61a and 63a may be opened. When the cooling water is heated by the heater 60, the valve 63a
, And the valves 60a, 61a, and 62a may be opened. Thus, the upstream side of the low-temperature natural gas heater 32
In addition to installing the heater 60 at the appropriate time, by providing a bypass pipe in an appropriate portion, even when the ambient temperature is high such as in summer,
Even in the case where there is a possibility that the cooling water may freeze due to a decrease in the atmospheric temperature in winter, the remaining cold of the LNG can be collected as a cooling water cooling source, and the raw material air and the like can be sufficiently cooled. In addition, when the heater 60 is installed, a heating source is required, but it requires much less power than the CFC refrigerator requires.
The power cost reduction effect of cold recovery is much greater.

The arrangement and piping of the various devices are in an appropriate state in consideration of various conditions such as the amount of raw material air (the scale of the air liquefaction separator), the amount of LNG, the amount of cooling water, and the cooling capacity of each part. Can be Further, the form of the low-temperature natural gas heater may be such that another heat medium may be interposed between the cooling water and the low-temperature natural gas, and may be an indirect heat exchanger system such as an open rack vaporizer or a shell and tube. Good. Further, in the above embodiment, the cold was recovered from the vaporized low-temperature natural gas. However, LNG may be directly introduced into the low-temperature natural gas heater (LNG evaporator and heater) to be vaporized. Further, an indirect heat exchanger may be used instead of the washing cooling tower.

[0032]

As described above, according to the present invention,
By collecting the excess refrigeration of LNG, which had been released into the atmosphere or seawater, with the cooling water in the cooling water cooling equipment of the air liquefaction / separation unit, it was attached to the sufficiently cooled raw air precooling cooling water and compressor. Cooling water for the cooler can be easily obtained. Further, the outlet temperature of the low-temperature natural gas can be kept constant.

Accordingly, the power cost in the cooling water cooling equipment of the air liquefaction / separation device can be reduced, the adsorption efficiency of the adsorber and the compression efficiency of the compressor can be improved, and the efficiency of the entire air liquefaction / separation device can be improved. .

[Brief description of the drawings]

FIG. 1 is a system diagram of a cooling water cooling system showing an embodiment of the present invention.

FIG. 2 is a system diagram of a cooling water cooling system showing another embodiment of the present invention.

FIG. 3 is a system diagram showing an example of an air liquefaction / separation apparatus using the cold of LNG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Raw material air compressor 1a, 1b ... Aftercooler and intercooler 2 ... Rinse cooling tower 30 ... Cooling equipment 31 ... Compressor cooler 32 ... Low temperature natural gas heater 33 ... Air-cooled cooling tower 60 ... Heater

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25J 1/00-5/00

Claims (14)

(57) [Claims] 1. Each part of the air liquefaction / separation apparatus is cooled by cooling water.
Cooling means for cooling, and air cooling for air cooling the cooling water
Tower, the air-cooled cooling tower and the cooling means,
Cooling water cooling system equipped with a circulating cooling water circulation system
In the method for cooling the cooling water, the nitrogen gas and the liquefied natural gas in the air liquefaction / separation apparatus are subjected to heat exchange to recover a part of the cold and vaporize the low-temperature natural gas before introducing the cooling means.
Wherein the cooling water and Rukoto to heat exchange to recover refrigeration and warmed the cold natural gas, said by cold that the recovery of
A cooling water cooling method for an air liquefaction / separation apparatus utilizing the cooling of liquefied natural gas , wherein the cooling water is cooled before introducing cooling means . 2. Cooling water cooled and recovered by heat exchange with the low-temperature natural gas is introduced into a washing / cooling tower installed in the air liquefaction / separation apparatus, and the cooling water is introduced into the washing / cooling tower .
The compressed raw material air is brought into direct contact with the compressed raw material air to be introduced.
2. The method for cooling cooling water of an air liquefaction / separation apparatus according to claim 1, wherein air is cooled. 3. The compression installed in the air liquefaction separation device.
Machine intercooler and / or aftercooler,
Cooling water that has been subjected to cold recovery by heat exchange with the low-temperature natural gas is introduced, and the cooling water is introduced between the gas and the gas compressed by the compressor.
2. The cooling water cooling method for an air liquefaction / separation apparatus according to claim 1, wherein said gas is cooled by heat exchange . 4. The cooling for exchanging heat with the low-temperature natural gas.
Adjust the temperature and water temperature so that the water volume and temperature are the same.
The flow rate ratio of the cooling water in the cooling water circulation system
The refrigeration of liquefied natural gas according to claim 1,
The cooling water cooling method of the air liquefaction / separation device used . 5. The cooling water of the cooling water circulating system is controlled by temperature or temperature.
2. The method according to claim 1, wherein the heating is performed according to the water temperature.
Cooling of air liquefaction and separation equipment using refrigeration of liquefied natural gas
Water cooling method . 6. Each part of the air liquefaction / separation apparatus is cooled by cooling water.
Cooling means for cooling, and air cooling for air cooling the cooling water
Tower, the air-cooled cooling tower and the cooling means,
Cooling water cooling system equipped with a circulating cooling water circulation system
In the apparatus for cooling the cooling water according to the above,
Heat exchange between nitrogen gas and liquefied natural gas
Liquefied natural gas heat exchange means for recovering liquefied natural gas
Low-temperature natural gas that has been partially vaporized by heat exchange means and vaporized
Heat exchange between the gas and the cooling water before introducing the cooling means.
To recover the cold by heating the low-temperature natural gas
Due to the collected cold, the cooling water before introducing the cooling means
And a low-temperature natural gas heater for cooling the liquefied natural gas. 7. The low-temperature natural liquefaction / separation apparatus according to claim 1,
Cooling water is recovered by cooling with heat exchange with gas
Introduced and brought into direct contact with the compressed raw material air
7. A cooling water cooling device for an air liquefaction / separation device utilizing refrigeration of liquefied natural gas according to claim 6, further comprising a washing cooling tower for cooling the liquefied natural gas. 8. The compressor of the air liquefaction separation device,
Cold recovery and cooling by heat exchange with low-temperature natural gas
Introducing cooling water, gas compressed by the compressor and indirect heat
An intercooler for cooling the gas by replacement
The cooling water cooling device for an air liquefaction / separation device using refrigeration of liquefied natural gas according to claim 6 or 7, further comprising an aftercooler . 9. The low-temperature natural gas heater includes a heater.
A part of the cooling water derived from the heater is returned directly to the inlet of the heater.
The cooling water cooling device for an air liquefaction / separation device utilizing refrigeration of liquefied natural gas according to any one of claims 6 to 8, further comprising a conduit for adjusting a return amount of the liquefied natural gas. 10. The cooling water circulation system includes the air-cooled cooling system.
Part of the cooling water derived from the tower is heated by the low-temperature natural gas
Conduit and flow rate bypassing the vessel and introducing directly to said cooling means
Claim: A valve for adjusting pressure is provided.
10. A cooling water cooling device for an air liquefaction / separation device utilizing the refrigeration of liquefied natural gas according to any one of 6 to 9 . 11. The cooling water circulation system according to claim 1 , wherein:
A heater for heating the cooling water is provided upstream of the gas heater.
11. The method according to claim 6, wherein:
2. A cooling water cooling device for an air liquefaction / separation device utilizing the refrigeration of liquefied natural gas according to claim 1 . 12. The cooling water circulation system includes an air-cooled cooling system.
A bypass for introducing the cooling water into the heater, bypassing the cooling tower
The cooling water cooling device for an air liquefaction / separation device using refrigeration of liquefied natural gas according to claim 11, further comprising a pass pipe and a valve for adjusting a flow rate . 13. The cooling water circulation system includes the heater
A bypass pipe to bypass and a valve to regulate the flow rate are provided
Cooling water cooling system of an air separation plant utilizing the cold of liquefied natural gas according to claim 11 or 12 further characterized in that there. 14. A cooling device for cooling each part of the air liquefaction / separation apparatus.
A cooling device for recirculating water, wherein the air liquefaction / separation device comprises:
Rinse air compressor and water cooling to clean and cool the raw air
Heat exchange between the nitrogen gas and liquefied natural gas
Liquefied natural gas heat exchange to recover part of the liquefied natural gas cold
A circulating nitrogen system provided with a means, wherein the cooling device comprises:
Cooling each part of the air liquefaction separation device with cooling water
Cooling means, an air-cooled cooling tower for air-cooling the cooling water,
Circulating the cooling water to the cooling tower and the cooling means
Cooling water circulation system, and the cooling water circulation system
Part of the cold collected by the liquefied natural gas heat exchange means
Low temperature natural gas and the cooling water before introducing the cooling means
And heat the low-temperature natural gas to recover the cold.
The cooling means is introduced by the collected cold
A low-temperature natural gas heater for cooling said cooling water,
The cooling water is provided upstream of the warm natural gas heater.
A heater to be heated, and a bypass pipe and a flow bypassing the heater.
A valve for adjusting the flow rate and the cooling air bypassing the air-cooled cooling tower.
Adjust the bypass pipe and the flow rate to introduce the cooling water into the heater
A cooling water cooling device for an air liquefaction / separation device utilizing the refrigeration of liquefied natural gas.