KR20160114212A - A Treatment System of Liquefied Gas - Google Patents

Abstract

A liquefied gas processing system according to an embodiment of the present invention comprises a liquefaction unit to liquefy evaporated gas discharged from a liquefied gas storage tank to liquefy part of the evaporated gas using the liquefaction unit, mix the liquefied gas which is liquid with the evaporated gas which is gas and return the mixed gas to the liquefied gas storage tank, wherein the size of the liquefaction unit is to store at least 200% of the amount of evaporated gas generated in the liquefied gas storage tank and decreases the amount of the evaporated gas inside the liquefied gas storage tank below the storage capacity by liquefying the evaporated gas at least once. The liquefied gas processing system according to the present invention is able to prevent damage to the liquefied gas storage tank by making the storage capacity of the liquefaction unit correspond to 200% of the amount of evaporated gas generating in the liquefaction gas storage tank and not causing to the storage capacity to exceed the threshold value of the liquefied gas storage tank, stabilize the system and save fuel costs since the system does not need to dump evaporated gas or to operate consumers with an unnecessarily excessive load.

Description

Description of the Related Art A Treatment System of Liquefied Gas

The present invention relates to a liquefied gas processing system.

Liquefied natural gas (Liquefied natural gas), Liquefied petroleum gas (Liquefied petroleum gas) and other liquefied gas are widely used in place of gasoline or diesel in recent technology development.

Liquefied natural gas is a liquefied natural gas obtained by refining natural gas collected from a gas field. It is a colorless and transparent liquid with almost no pollutants and high calorific value. It is an excellent fuel. On the other hand, liquefied petroleum gas is a liquid fuel made by compressing gas containing propane (C3H8) and butane (C4H10), which come from oil in oil field, at room temperature. Liquefied petroleum gas, like liquefied natural gas, is colorless and odorless and is widely used as fuel for household, business, industrial, and automotive use.

Such liquefied gas is stored in a liquefied gas storage tank installed on the ground or stored in a liquefied gas storage tank provided in a ship which is a means of transporting the ocean. The liquefied natural gas is liquefied to a volume of 1/600 The liquefaction of liquefied petroleum gas has the advantage of reducing the volume of propane to 1/260 and the content of butane to 1/230, resulting in high storage efficiency.

These liquefied gases are supplied to various customers and used. Recently, LNG carrier that uses LNG as fuel for LNG carriers that transport liquefied natural gas has been developed. The method used is applied to ships other than LNG carriers.

However, the temperature and pressure of the liquefied gas required by the customer such as the engine may be different from the state of the liquefied gas stored in the liquefied gas storage tank. Therefore, recently, research and development have been conducted on technologies for controlling the temperature and pressure of the liquefied gas stored in a liquid state to supply it to a customer.

Particularly, a liquefied gas processing system that liquefies the evaporation gas to prevent waste of fuel generally has a re-liquefaction efficiency of 50%, and will be described with reference to the drawings.

1 is a view showing a state change of the amount of evaporated gas recovered in a general liquefied gas processing system.

Referring to FIG. 1, the liquefied gas processing system is configured such that the evaporated gas discharged from the liquefied gas storage tank 110 is partially liquefied in the liquefier 140, returned to the liquefied gas storage tank 110, and stored.

For example, in the liquefied gas storage tank 110, 3.4 tons of evaporation gas is generated per hour, and as a result of accumulation of evaporation gas over time, the amount of evaporation gas discharged from the liquefied gas storage tank 110 is 7 ton The dischargeable amount per hour), and the possible size of the evaporation gas of the liquefier 140 is 3.4 tons or less.

7 ton of evaporative gas is accumulated in the liquefied gas storage tank 110 and 7 tons of evaporative gas is discharged from the liquefied gas storage tank 110 to the liquefier 140 as shown in FIG.

1B, when the evaporation gas is recovered to the liquefier 140, the acceptable size of the liquefier 140 is 3.4 tons. Therefore, 3.6 tons of evaporation gas, which can not be accommodated in 7 tons, And 1.7 tons of the remaining 3.4 tons is liquefied so that 5.3 tons of evaporated gas of 3.6 + 1.7ton is recovered to the liquefied gas storage tank 110. [ At this time, the liquefied gas in the liquefied gas storage tank 110 loses 3.4 ton of evaporated gas over time.

Then, as shown in FIG. 1 (c), the dischargeable 7 tons of 3.4 + 5.3 tons accumulated in the liquefied gas storage tank 110 is discharged and the remaining 1.7 tons remains in the liquefied gas storage tank 110 in FIG. .

Then, as shown in FIG. 1 (d), the amount of the evaporated gas that can not be liquefied in 7 tons through the liquefier 140 is 5.3 ton (the evaporation gas corresponding to the capacity accommodated in the liquefier, At this time, the liquefied gas storage tank 110 is additionally provided with 3.4 ton of evaporative gas due to passage of time, and the evaporated gas of 1.7 tons which has not been discharged previously remains. Therefore, The evaporated gas loaded into the liquefied gas storage tank 110 by 5.3 tons becomes 10.4 tons which is 1.7 + 3.4 + 5.3 tons.

Then, as shown in FIG. 1E, 7 tons of evaporative gas, which can be discharged through a pipe (not shown), is discharged to the liquefier 140 from 10.4 tons accumulated in the liquefied gas storage tank 110, ton remains.

Thus, even if the evaporation gas is liquefied through the liquefier 140, the liquefied gas storage tank 110 accumulates evaporated gas that has not been liquefied, resulting in the liquefied gas storage tank 110 exceeding the pressure resistance threshold value. There is a possibility that the liquefied gas storage tank 110 may be damaged when the internal pressure threshold value is exceeded. Therefore, there is a possibility that the system is inefficiently operated such that the load of the liquefied gas consumer (not shown) is increased or the evaporation gas is discarded.

It is an object of the present invention to provide a liquefied gas storage tank that is capable of storing liquefied gas due to accumulation of un-liquefied evaporated gas in a process of re- And to provide a liquefied gas processing system that prevents breakage of the tank.

A liquefied gas processing system according to an embodiment of the present invention includes a liquefied portion for liquefying the evaporated gas discharged from a liquefied gas storage tank so that a part of the evaporated gas is liquefied by the liquefied portion, The liquefied gas processing system according to any one of claims 1 to 3, wherein the liquefied gas is at least one liquefied gas storage tank So that the evaporation gas in the liquefied gas storage tank converges to a capacity less than the capacity of the liquefied gas storage tank.

Specifically, the evaporation gas generated in the liquefied gas storage tank is characterized by following equation (1). Equation _{(1): a n = {} X + (a n-1) / 2} where, a _n is the amount of boil-off gas to be stored are stacked in the liquefied gas storage tank, X is in the liquefied gas storage tanks The amount of naturally occurring evaporative gas generated.

Specifically, it is characterized by further comprising an evaporative gas compressor for compressing the evaporative gas supplied from the liquefied gas storage tank.

Specifically, the liquefier may include: an evaporative gas liquefier which liquefies or at least partially liquefies the evaporated gas compressed in the evaporative gas compressor; A gas-liquid separator for separating a liquid and a gas from an evaporation gas passing through the evaporation gas liquefier; And an evaporation gas heat exchanger for recovering the cold heat of the evaporation gas supplied from the liquefied gas storage tank and the cold gas of the gas supplied from the gas-liquid separator.

Specifically, the evaporation gas compressed in the evaporation gas compressor is heat-exchanged in the evaporation gas heat exchanger and is supplied to the evaporation gas liquefier.

The liquefied gas processing system according to the present invention can reduce the liquefied gas storage tank threshold by matching the capacity of the liquefier to 200% of the amount of evaporated gas generated in the liquefied gas storage tank It is possible not only to prevent the liquefied gas storage tank from being damaged, but also to evaporate the evaporation gas unnecessarily, or to drive the liquefied gas consumer to a load more than necessary There is no need to stabilize the system and reduce the fuel cost.

1 is a view showing a state change of the amount of evaporated gas recovered in a general liquefied gas processing system.
2 is a conceptual diagram showing a liquefied gas processing system according to an embodiment of the present invention.
3 is a view showing a state change of the amount of evaporated gas recovered in the liquefied gas processing system according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements have the same numerical numbers as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a conceptual diagram showing a liquefied gas processing system according to an embodiment of the present invention, and FIG. 3 is a diagram showing a state change of the amount of evaporated gas recovered in the liquefied gas processing system according to an embodiment of the present invention .

2 and 3, a liquefied gas processing system 1 according to an embodiment of the present invention includes a liquefied gas storage tank 10, a liquefied gas consumer 20, an evaporative gas compressor 30, An evaporation gas heat exchanger 41, an evaporation gas liquefier 42, and a gas-liquid separator 43.

The liquefied gas storage tank 10 stores liquefied gas to be supplied to the liquefied gas consumer 20. The liquefied gas storage tank 10 must store the liquefied gas in a liquid state, wherein the liquefied gas storage tank 10 may have the form of a pressure tank.

In the present embodiment, the evaporation gas generated in the liquefied gas storage tank 10 is supplied to the evaporation gas compressor 30 to be used for heating the evaporation gas, or the evaporation gas is vaporized and pressurized, , The evaporation gas can be efficiently used.

The liquefied gas consumer 20 is driven through the evaporation gas supplied from the liquefied gas storage tank 10 to generate power. At this time, the liquefied gas consumer 20 is a high-pressure engine, and may be a gas fuel engine (for example, MEGI).

As a piston (not shown) in the cylinder (not shown) reciprocates by the combustion of the liquefied gas, the liquefied gas consumer 20 rotates a crankshaft (not shown) connected to the piston, The shaft (not shown) to be connected can be rotated. Therefore, as the propeller (not shown) connected to the shaft rotates when the liquefied gas consumer 20 is driven, the hull can move forward or backward.

Of course, in this embodiment, the liquefied gas consumer 20 may be an engine for driving the propeller, but it may be an engine for generating power or an engine for generating other power. That is, the present embodiment does not particularly limit the kind of the liquefied gas consumer 20. However, the liquefied gas consumer 20 may be an internal combustion engine that generates a driving force by the combustion of the evaporative gas and the flash gas.

The liquefied gas consumer 20 is supplied with the evaporated gas pressurized by the evaporative gas compressor 30 to obtain the driving force. The state of the evaporated gas supplied to the liquefied gas consumer 20 may vary depending on the state required by the liquefied gas consumer 20.

An evaporative gas supply line 16 for transferring evaporative gas may be installed between the liquefied gas storage tank 10 and the liquefied gas consumer 20 and a forced vaporizer and an evaporative gas heat exchanger Liquid separator 43 and the like so that the evaporated gas can be supplied to the liquefied gas consumer 20 or to the gas-liquid separator 43. The gas-liquid separator 43 is provided with an evaporation gas compressor 41, an evaporation gas compressor 30, an evaporation gas liquefier 42, have.

At this time, a fuel supply valve (not shown) is provided in the evaporation gas supply line 16 so that the supply amount of the evaporation gas can be adjusted according to the adjustment of the opening degree of the fuel supply valve.

The evaporative gas compressor (30) pressurizes the evaporative gas generated in the liquefied gas storage tank (10). The evaporation gas compressor 30 can pressurize the evaporation gas generated and discharged from the liquefied gas storage tank 10 and supply it to the evaporation gas heat exchanger 41 or the liquefied gas consumer 20.

A plurality of evaporation gas compressors (30) can be provided to pressurize the evaporation gas at multiple stages. For example, five evaporation gas compressors 30 may be provided so that the evaporation gas is pressurized in five stages.

Here, the evaporation gas supply line 16 may be branched between the evaporation gas compressor 30 and the liquefied gas consumer 20, and may be connected to the evaporation gas heat exchanger 41. That is, the evaporation gas supply line 16 may be connected to the liquefied gas consumer 20 in the evaporative gas compressor 30, or may be connected to the evaporation gas heat exchanger 41.

At this time, a valve (not shown) may be provided on the evaporation gas supply line 16 at a branch point to the evaporation gas heat exchanger 41. The valve may be a flow rate of the evaporation gas supplied to the liquefied gas consumer 20 The flow rate of the evaporation gas supplied to the evaporation gas heat exchanger (41) through the evaporation gas compressor (30) can be controlled, and can be a three-way valve.

As the evaporation gas compressor 30 pressurizes the evaporation gas, the evaporation gas can be in a state where the pressure rises and the boiling point rises and can be liquefied even at a relatively high temperature. Therefore, in this embodiment, by increasing the pressure of the evaporation gas to the evaporation gas compressor 30, the evaporation gas can be easily liquefied.

An evaporation gas heat exchanger (41) is provided between the liquefied gas storage tank (10) and the evaporative gas compressor (30) on the evaporation gas supply line (16). The evaporation gas heat exchanger 41 is capable of exchanging heat between the evaporation gas pressurized by the evaporation gas compressor 30 and the evaporation gas supplied from the liquefied gas storage tank 10 and the flash gas separated from the gas-liquid separator 43.

That is, the evaporation gas heat exchanger 41 is provided with evaporation gas recovered along the evaporation gas supply line 16 which is pressurized by the evaporation gas compressor 30 and branches upstream in the liquefied gas consumer, Exchanges the supplied evaporation gas. The evaporation gas heat exchanger 41 exchanges heat between the evaporated gas that is pressurized in the evaporative gas compressor 30 and recovered along the evaporative gas supply line 16 and the flash gas supplied through the gas recovery line 17.

At this time, the evaporation gas heat exchanger 41 can cool the evaporation gas recovered along the evaporation gas supply line 16 to the evaporation gas supplied from the liquefied gas storage tank 10, Lt; RTI ID = 0.0 > flash gas. ≪ / RTI > In this case, the evaporated gas recovered along the evaporated gas supply line 16 is primarily cooled by the evaporated gas discharged from the liquefied gas storage tank 10, and can be cooled secondarily by the flash gas.

The evaporation gas heat exchanger (41) supplies the evaporation gas supplied from the liquefied gas storage tank (10) to the evaporation gas compressor (30), and the evaporation gas secondarily cooled by the evaporation gas and the flash gas is supplied to the evaporation gas liquefier (42). In this case, since the evaporation gas supplied to the evaporation gas liquefier 42 is cooled not only by the evaporation gas but also by the flash gas, the liquefaction efficiency due to the reduced pressure can be increased.

The evaporation gas liquefier 42 is pressurized in the evaporation gas compressor 30 to reduce the evaporated gas heat-exchanged in the evaporation gas heat exchanger 41. For example, the evaporating gas liquefier 42 can reduce the evaporating gas to about 3 bar, and the evaporating gas can be cooled when the pressure is reduced.

Here, the evaporated gas pressurized in the evaporative gas compressor 30 is cooled by heat exchange with the evaporated gas supplied from the liquefied gas storage tank 10 in the evaporated gas heat exchanger 41, but the pressure is discharged from the evaporated gas compressor 30 The discharge pressure can be maintained. This embodiment uses the evaporation gas liquefier 42 to depressurize the evaporation gas so that the evaporation gas can be cooled to liquefy the evaporation gas. At this time, the larger the pressure range to be depressurized, the greater the cooling effect of the evaporative gas.

Evaporative gas liquefier 42 may be a line Thompson valve. In the case of the Row Thompson valve, depressurization can effectively cool the evaporated gas so that at least some of the evaporated gas is liquefied.

Since the evaporated gas decompressed by the evaporated gas liquefier 42 is cooled by the evaporated gas supplied from the liquefied gas storage tank 10 and also cooled by the flash gas supplied from the gas-liquid separator 43, Anger can be achieved. That is, this embodiment can utilize the cold heat of the flash gas, so that the re-liquefaction efficiency higher than that using the heat exchange between the evaporated gases can be obtained.

A gas-liquid separator (60) separates the gas from the decompressed gas in the gas-liquid evaporator (42). In the gas-liquid separator 43, the evaporation gas is separated into a liquid and a gas so that the liquid is supplied to the liquefied gas storage tank 10, and the gas can be recovered as a flash gas to the evaporation gas heat exchanger 41.

Here, the evaporation gas supplied to the gas-liquid separator 43 may be decompressed and cooled in the evaporation gas liquefier 42. Wherein the evaporation gas may be at least partially liquefied and the remainder may be in gaseous flash gas. In this case, the flash gas also has a state of about -150 degrees, and the flash gas of -150 degrees is supplied to the evaporation gas heat exchanger 41 in the gas-liquid separator 43 and can be used to cool the evaporation gas.

As described above, in this embodiment, since the evaporation gas supplied to the gas-liquid separator 43 is sufficiently cooled by the evaporation gas and the flash gas in the evaporation gas heat exchanger 41 and then cooled down by the evaporation gas liquefier 42, The liquefaction efficiency of the evaporation gas can be improved.

In this embodiment, the liquefied evaporated gas can be recovered in the liquefied gas storage tank 10 and the flash gas generated in the gas-liquid separator 43 can be recovered in the evaporated gas heat exchanger 41 to heat-exchange the evaporated gas .

Liquid separator 43 separates the vaporized gas into a liquid and a gas and the liquefied evaporated gas and the flash gas are respectively supplied to the liquefied gas storage tank 10 and the evaporation gas storage tank 10 through the liquid recovery line 19 and the gas recovery line 17, Gas heat exchanger (41).

The liquid recovery line 19 is connected from the gas-liquid separator 43 to the liquefied gas storage tank 10 to recover the vaporized liquid state to the liquefied gas storage tank 10 and the gas recovery line 17 is connected to the gas- 43 to the evaporation gas heat exchanger 41 to recover the flash gas to the evaporation gas heat exchanger 41 to heat-exchange the evaporation gas.

The evaporation gas liquefier 42, the gas-liquid separator 43 and the evaporation gas heat exchanger 41 described in this embodiment are used as the liquefier 40 and the evaporation gas discharged from the liquefied gas storage tank 10 As described above, a part of the liquid is liquefied and recovered into the liquefied gas storage tank 10.

However, when the liquefier 40 is provided at a size of a capacity equal to or smaller than the amount of evaporated gas generated in the liquefied gas storage tank 10, the evaporated gas discharged from the liquefied gas storage tank 10 is not consumed, When the liquefied gas consumer 20 is driven (driven at a low speed) to such an extent that the liquefied gas is stored in the liquefied gas storage tank 10, the amount of the evaporated gas accumulates in the liquefied gas storage tank 10 and the internal pressure can be increased. At this time, the liquefied gas storage tank 10 exceeds the internal pressure threshold value, and there is a fear of breakage.

For example, in the liquefied gas storage tank 10, 3.4 tons of evaporative gas is generated per hour, the amount of evaporative gas discharged from the liquefied gas storage tank 10 is 7 tons per hour, the evaporated gas is circulated through the liquefier, A description will be given of a case where the evaporable gas acceptable size of the liquefied portion is 3.4 tons or less when returning to the gas storage tank 10.

At this time, the liquefaction ratio of the liquefier is made to be 50% (which is based on the general liquefaction ratio). And 7 tons corresponding to the capacity of the liquefied gas storage tank 10 are accumulated, the evaporated gas recovered to the liquefied gas storage tank 10 through the liquefier is discharged to the evaporation gas heat exchanger, the evaporative gas liquefier, and the gas- (7 - 3.4) ton which has not been liquefied while passing through is recovered to the liquefied gas storage tank 10 as it is. In addition, 1.7 ton, which is half of the 3.4 ton capacity that can be accommodated in the liquefier 40, There is a possibility that the amount of the evaporated gas gradually accumulates and exceeds the threshold value as the evaporated gas of (3.6 + 1.7) ton is recovered to the tank 10 and is recovered to the liquefied gas storage tank 10.

That is, when the amount of the evaporated gas exceeding the capacity of the liquefier is discharged from the liquefied gas storage tank 10, the amount of the evaporated gas returned to the liquefied gas storage tank 10 is gradually accumulated.

At this time, the present embodiment increases the size of the liquefier 40 so as not to unnecessarily drive the liquefied gas consumer 20 to waste the evaporation gas, such as to increase the driving capacity of the evaporative gas compressor 30 .

That is, the capacity of the liquefier 40 is 7 tons, which is more than twice the capacity of 3.4 tons generated in the liquefied gas storage tank 10. In the liquefier 40, the same amount as 3.6 + 1.7 tons , But 3.5ton, half of 7ton, can be recovered.

Here, the liquefier 40 is sized to receive at least 200% of the amount of evaporative gas generated in the liquefied gas storage tank 10, so that the evaporation gas in the liquefied gas storage tank 10 To be less than the capacity of the liquefied gas storage tank (10).

Particularly, in the present embodiment, the evaporation gas according to the following equation (1) can be stored in the liquefied gas storage tank 10.

(1): a _n = {X + (a _n-1 ) / 2}

Here, a _n is the amount of evaporated gas accumulated and stored in the liquefied gas storage tank 10, and X is an example of 3.4 tons as the amount of evaporated gas naturally generated in the liquefied gas storage tank 10.

Accordingly, the amount of evaporation gas (a _n ) stored in the liquefied gas storage tank 10 is 50% (corresponding to the general liquefaction ratio), and the amount of evaporation gas (a _n ) stored in the liquefied gas storage tank 10 ), The liquefier 40 is driven so that a 1 (the present embodiment can be presented as the case where 1 hour has elapsed since the calculation is performed per hour) is assumed to be a ₁ in = 7/2 + 3.4 = 3.4 + 3.5 = 6.9 ton, the amount of generation, and twice _{a 2 = 3.4 + 6.9 / 2} = 3.4 + 3.45 =, a liquefied gas storage tank, as the amount of 6.856 ton occurs ( 10, the amount of evaporative gas stored in the liquefied gas storage tank 10 accumulated by the recovery of the remaining evaporated gas by the liquefier 40 is 6.8 tons And is equal to or less than 7 ton, which is the threshold value of the liquefied gas storage tank 10.

3, when the amount of the evaporable gas that can be discharged through the evaporation gas supply line 16 is 7 tons, for example, the load of the liquefied gas consumer 20, as shown in FIG. 3 (a) 7 tons of evaporative gas is accumulated in the liquefied gas storage tank 10, and 7 tons of evaporative gas is discharged from the liquefied gas storage tank 10 to the liquefier 40. [

Then, when the evaporation gas is recovered to the liquefier 40 as shown in Fig. 3B, since the acceptable size of the liquefier 40 is 7 tons, 3.5 tons of 7 tons is liquefied and the liquefied An amount of 3.5 tons of evaporation gas is recovered to the liquefied gas storage tank 10. At this time, the liquefied gas in the liquefied gas storage tank 10 generates 3.4 ton of evaporated gas over time.

Then, as shown in FIG. 3C, since the dischargeable amount of 3.4 + 3.5 tons accumulated in the liquefied gas storage tank 10 in FIG. 3B is 7 tons, the evaporated gas in the liquefied gas storage tank 10 of 6.9 tons So that evaporated gas does not remain in the liquefied gas storage tank 10 (which is roughly equivalent to 1.7 tons remaining in the prior art).

Then, as shown in FIG. 3 (d), 3.45 tons of evaporative gas, which is half 6.9 tons, is recovered through the liquefier 40. [ At this time, the evaporated gas loaded into the liquefied gas storage tank 10 by the recovered 3.45 tons is 3.4 + 3.45 (m3) because the evaporated gas of 3.4ton is additionally generated in the liquefied gas storage tank 10 due to the passage of time. ton.

Then, as shown in FIG. 3E, 6.85 tons accumulated in the liquefied gas storage tank 10 is discharged to the liquefier 140, so that half of the evaporated gas is liquefied and accumulated in the liquefied gas storage tank 10 The amount of the evaporated gas is exhausted because the amount of the evaporable gas that can be discharged through the evaporated gas supply line 16 is 7 tons or less (which is roughly equivalent to 3.4 tons remaining in the past).

As described above, in the present embodiment, the storage capacity of the liquefier 40 is made to correspond to 200% of the amount of evaporated gas generated in the liquefied gas storage tank 10, It is possible not only to prevent the liquefied gas storage tank 10 from being damaged but also to evaporate the evaporation gas unnecessarily or to drive the liquefied gas consumer 20 to a load more than necessary There is no need to stabilize the system and reduce the fuel cost.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification and the modification are possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: liquefied gas processing system 10: liquefied gas storage tank
16: Evaporative gas supply line 17: Gas recovery line
19: liquid recovery line 20: liquefied gas consumer
30: Evaporative gas compressor 40: Liquefier
41: Evaporative gas heat exchanger 42: Evaporative gas liquefier
43: gas-liquid separator

Claims (5)

And a liquefied portion for liquefying the evaporated gas discharged from the liquefied gas storage tank, wherein a part of the evaporated gas is liquefied by the liquefied portion to mix the liquefied gas, which is liquid, with the evaporated gas, In a gas treatment system,
Wherein the liquefier is sized to receive at least 200% of the amount of evaporative gas generated in the liquefied gas storage tank so that evaporative gas in the liquefied gas storage tank is less than the storage capacity of the liquefied gas storage tank To the liquefied gas processing system. The method according to claim 1,
Characterized in that the evaporated gas generated in said liquefied gas storage tank is according to equation (1).

(1): a _n = {X + (a _n-1 ) / 2}
Where a _n is the amount of evaporative gas accumulated and stored in the liquefied gas storage tank and X is the amount of naturally occurring evaporative gas generated in the liquefied gas storage tank. The method according to claim 1,
And an evaporative gas compressor for compressing the evaporative gas supplied from the liquefied gas storage tank. The liquid ejecting apparatus according to claim 3,
An evaporating gas liquefier for expanding or reducing the pressure of the evaporation gas compressed in the evaporation gas compressor to at least partially liquefy the evaporation gas;
A gas-liquid separator for separating a liquid and a gas from an evaporation gas passing through the evaporation gas liquefier; And
And an evaporative gas heat exchanger for recovering the cold heat of the evaporated gas supplied from the liquefied gas storage tank and the cold gas of the gas supplied from the gas-liquid separator, characterized in that the evaporated gas heat exchanger system. 5. The method of claim 4,
Wherein the evaporated gas compressed in the evaporative gas compressor is heat-exchanged in the evaporative gas heat exchanger and fed to the evaporative gas liquefier.

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