KR101370940B1 - Multi Stage Refrigerating System And Operating Method Thereof - Google Patents

Abstract

A binary refrigeration system and its method of operation are disclosed. In the binary refrigeration system of the present invention, in a two-way refrigeration system having two or more refrigeration cycles, in order to normalize the operation of the refrigeration cycle of the first refrigerant, another refrigeration cycle of the corresponding refrigerant is used, but the heat exchange is performed in the primary heat exchanger. After the part of the first refrigerant is cooled in the other refrigeration cycle is characterized in that to return to the refrigeration cycle of the first refrigerant through the first heat exchanger again.

Description

Multi Stage Refrigerating System And Operating Method Thereof}

The present invention relates to a binary refrigeration system and a method of operating the same, and more particularly, to a dual refrigeration system and a method of operating the same using a compressor of the secondary refrigerant for rapid compression process and normalization of the refrigeration cycle in the primary refrigeration system. It is about.

The refrigerating cycle basically consists of four actions, and the refrigerant circulates repeatedly changing from liquid to gas and gas to liquid.

First is evaporation. The liquefied refrigerant flowing into the evaporator through the cooling tube evaporates in the evaporator, where the refrigerant liquid evaporates while removing heat (evaporative latent heat) necessary for evaporation from the air around the cooling tube. The deprived air is cooled down to a lower temperature, which is then spread into the freezer by natural convection or a fan.

The evaporator must be kept at a lower pressure to evaporate the refrigerant liquid at lower temperatures. This action is intended to keep the refrigerant pressure in the evaporator low, so that the liquid refrigerant can continue to evaporate vigorously even under low temperature conditions. The vaporized refrigerant vapor is introduced into the compressor.

Second is the compression action. The refrigerant vapor vaporized in the evaporator is sucked into the compressor. The refrigerant vapor sucked into the compressor is compressed by the piston in the cylinder of the compressor, and the pressure is increased so that the refrigerant vapor can be easily liquefied even if cooled by normal temperature cooling water or cooling air.

Third is condensation. Compressed gas from the compressor is in a state (high pressure) that can be easily liquefied by the coolant or cooling air at room temperature. A condenser is a heat exchanger that cools compressed gas to liquefy condensation, and water-cooling and air-cooling are widely used.

The liquefied refrigerant here accumulates in the receiver. The heat released to the cooling water or cooling air from the high-temperature, high-pressure refrigerant exiting the compressor is called condensation heat, and this heat is the sum of the heat taken by the refrigerant from the freezer in the evaporator and the amount of heat applied to compress it.

In the case of condensation, like evaporation, the refrigerant is a state in which vapor and liquid coexist, and there is a constant relationship between pressure (condensing pressure) and temperature during the transition from gas to liquid, and when the pressure is determined, the temperature is determined. On the contrary, when the temperature is set, the pressure is set. Such a relationship between the condensation temperature and the condensation pressure is changed depending on the type of refrigerant and the difference in the condensation temperature even with the same refrigerant.

Fourth, the expansion action. The action of lowering the pressure to a state that is easy to evaporate before sending the liquefied refrigerant to the evaporator is called expansion. The expansion valve which acts in this way acts as a depressurizing action and simultaneously controls the flow rate of the refrigerant liquid. In other words, the amount of refrigerant evaporated in the evaporator is determined according to the amount of heat (cooling load) to be removed in the refrigerating device under a predetermined evaporation temperature (evaporation pressure). Controlling what to send is very important.

The refrigerant circulates in these four operations sequentially and performs the role of a medium for moving (cooling) heat from a low temperature to a high temperature by circulating in the system of the refrigerating device.

On the other hand, when the cryogenic apparatus is below -70 ° C, it is difficult to realize the cryogenic temperature by the multi-stage compression method. Therefore, the multiple-way refrigeration system has been developed as an improvement of the refrigeration apparatus.

What is important in the cryogenic system is that the refrigerant in the evaporator in the cryogenic tank is easily evaporated under a suitable pressure. Freon-13, ethylene and the like are used as the refrigerant having such low temperature characteristics. Freon-13 has an evaporation pressure of 0.339 kg / cm 2 abs at -100 ° C., and it can be seen that the thermodynamic properties are excellent at cryogenic temperatures.

However, since such a refrigerant is at a substantially high pressure at room temperature or exceeds a critical temperature (critical temperature 28.8 ° C. for Freon-13), a refrigeration cycle cannot be realized with cooling water or cooling air at room temperature. Therefore, a refrigeration cycle that divides the refrigeration cycle into two stages in temperature and cools the condenser on the low temperature side with the evaporator on the high temperature side is used.

In such a case, Freon-22 is commonly used in the high temperature side and the low temperature side in a low temperature device up to about -70 ° C. However, at a temperature below that level, Freon-22 is used for the high temperature side and Freon-13 for the low temperature side. Refrigerant is used.

As described above, the dual refrigeration apparatus is a refrigeration apparatus in which two independent refrigeration cycles are combined in two steps in temperature, and a heat exchanger for moving heat on the low temperature side to the high temperature side is called a cascade condenser. Also, below -100 ° C, three-way refrigeration may be employed.

The refrigerant used in the refrigerating cycle is a liquid that tends to evaporate, and serves to absorb and heat the low temperature part while transporting and discharging the low temperature part while repeating the refrigerating cycle in the cooling device. Such refrigerants are classified into primary refrigerants and secondary refrigerants. The primary refrigerant is a refrigerant having a phase change process vaporized in the low temperature portion of the vapor compression refrigeration system and condensed and liquefied in the high temperature portion, and the secondary refrigerant is a refrigerant that carries low temperature heat without a phase change. Can be.

1 schematically illustrates the principle of C3MR of a LNG liquefaction plant to which a binary refrigeration system is applied.

It is a refrigeration system using propane as the primary refrigerant and mixed refrigerant (mixed gas of methane, ethane, propane and nitrogen) as the secondary refrigerant. The binary refrigeration cycle is composed of a primary refrigerant cycle portion (precooling) and a secondary refrigerant cycle portion (main cooling). The primary refrigerant cycle portion includes a suction drum (21) for storing primary refrigerant gas, a compression system (22) for compressing a gaseous refrigerant, and a condenser (23) for radiating and condensing heat of the refrigerant compressed in the compression system. Preheating the target gas through evaporation of the low-temperature and low-pressure refrigerant through the component, the receiver tank 24 for storing the condensed liquid refrigerant, the expansion valve 25 for lowering the condensed liquid refrigerant, and the components Heat exchanger 10 and the like.

And the primary refrigerant cycle portion has a temperature characteristic of the refrigerant almost similar to the general refrigeration cycle, the heat exchanger 10 maintains a low temperature, but compared to the heat exchanger 40 of the secondary refrigerant cycle portion described later Has a relatively high temperature.

The secondary refrigerant cycle portion may include a secondary refrigerant suction drum 31 in which refrigerant is stored, a compression system 32 for compressing a gaseous refrigerant, an intercooler 33 for cooling the compressed refrigerant, and a refrigerant backflow. It includes a check valve 34, a receiver tank 35 for storing the cooled refrigerant, and a heat exchanger 40 for performing heat exchange using the refrigerant of low temperature and low pressure. Here, the heat exchanger 40 of the secondary refrigerant cycle portion must be kept at a lower temperature than that to form a cryogenic temperature (eg, a low temperature of -60 to -70 ° C or lower) required in the freezing space. .

Two problems of the existing binary refrigeration system are pointed out. The first is the increase in the volume and installation cost of the installation due to the additional gas tank, or liquefied gas container and vaporizer for the storage of the primary refrigerant injected into the compressor of the pre-cooling cycle.

The second method is to secure the refrigerant gas required for the initial normal operation of the precooling cycle. In order for the binary refrigeration system to operate normally to achieve a sufficient cooling effect, the refrigeration cycle must be operated normally and proper heat exchange must be carried out.

Proper maintenance of the load conditions of the compressor and the amount of refrigerant circulated is essential for normal operation of this refrigeration cycle.

However, during the initial operation of the primary refrigerant, the refrigerant may not be completely vaporized in the primary heat exchanger, and even when fully vaporized, if the pipe length from the primary heat exchanger to the suction drum is long, it may be liquefied under the influence of external temperature. In this case, the liquid refrigerant is not introduced into the compressor through the separator 25 to prevent damage to the compressor.

This reduces the amount of refrigerant flowing into the compressor, thereby lowering the compressor load condition, resulting in a decrease in the amount of refrigerant circulated, thereby preventing the refrigeration cycle from operating normally.

In addition, when the compression process is not performed properly due to insufficient amount of refrigerant gas flowing into the compressor, the refrigerant, which has undergone two stages of compression through the bypass line, is re-injected into the compressor inlet instead of being sent to the condenser. Reducing the amount of primary refrigerant stored may cause a lack of sufficient precooling in the heat exchanger.

As a result, the abnormal operation of the precooling cycle interferes with the operation of the main cooling cycle. Therefore, for the normal operation of the dual cooling system, a sufficient amount of primary refrigerant gas to operate the compressor for a predetermined time during the initial operation of the primary refrigerant is required. Is required.

The present invention is to solve the conventional problems as described above, to reduce the system installation area by reducing the use of ancillary equipment by injecting the primary refrigerant in the liquid phase, and the secondary refrigerant compressor to normalize the initial operation of the primary refrigerant By making it possible to use, we want to solve the problem of normalization of the refrigeration cycle.

According to an aspect of the invention, the first heat exchanger is circulated supply of the first refrigerant for cooling the fluid to be cooled; A first refrigerant circulation supply unit configured to compressively cool and supply the first refrigerant to the primary heat exchanger; A secondary heat exchanger through which a second refrigerant for cooling the fluid to be cooled is circulated and supplied; A second refrigerant circulation supply unit configured to circulate and supply the second refrigerant by compression cooling the secondary heat exchanger; And after the first refrigerant heat-exchanged in the primary heat exchanger is compressed and cooled in the second refrigerant circulation supply unit, is supplied to the primary heat exchanger again, and heat exchanged with the cooling target fluid to return to the first refrigerant circulation supply unit. It provides a two-way refrigeration system comprising a first refrigerant return circulation supply.

The first refrigerant return circulation supply unit is provided in a line of the first refrigerant circulation supply unit to guide the first refrigerant heat exchanged in the primary heat exchanger to supply the second refrigerant circulation supply unit; And a third three-way valve provided in a line of the second refrigerant circulation supply unit to guide the first refrigerant heat-exchanged in the primary heat exchanger to the first refrigerant circulation supply unit.

The first refrigerant return circulation supply part is provided in a line of the second refrigerant circulation supply part so that the first refrigerant supplied to the second refrigerant circulation supply part is bypassed without being stored in the second receiver tank of the second refrigerant circulation supply part. Inducing second three-way valve may be included.

The first refrigerant circulation supply unit is installed in the rear end of the primary heat exchanger, the first suction drum for sucking the first refrigerant discharged from the primary heat exchanger; A first compression system for sucking and compressing the first refrigerant; A first condenser for condensing the compressed first refrigerant; A first receiver tank for accumulating the first refrigerant condensed; And a first expansion valve configured to circulate and supply the first refrigerant accumulated in the first receiver tank to the primary heat exchanger.

The first refrigerant circulation supply unit includes the first receiver tank into which the first refrigerant is injected in a liquid phase; A needle valve for controlling an amount of the first refrigerant injected into the first expansion valve; A first separator for separating the first refrigerant circulated through the first heat exchanger into a gas and a liquid; A gate valve controlling injection of the separated gas into the suction drum; A solenoid valve that regulates injection of the separated gas into the first compression system; A pressure regulator for regulating the pressure of the first refrigerant injected from the suction drum into the first compression system; And a control valve for controlling the injection of a first refrigerant from the suction drum to the first compression system.

The second refrigerant circulation supply unit is provided at a rear end of the secondary heat exchanger to suck the first refrigerant or the second refrigerant; A second compression system supplied with the first refrigerant or the second refrigerant from a second suction drum and compressed; And an intercooler in which the compressed first or second refrigerant is cooled, and a second receiver tank configured to accumulate the cooled second refrigerant.

The second refrigerant circulation supply unit includes a check valve to prevent refrigerant from flowing back into the intercooler; And a discharge port for discharging the first refrigerant remaining in the second refrigerant circulation supply unit.

The first refrigerant may be propane, and the second refrigerant may be a mixed refrigerant.

According to another aspect of the present invention, in a two-way refrigeration system having two or more refrigeration cycles, in order to normalize the operation of the refrigeration cycle of the first refrigerant, using a refrigeration cycle other than the refrigeration cycle of the refrigerant, in the primary heat exchanger A method of operating a dual refrigeration system for allowing a portion of the heat exchanged first refrigerant to be cooled in another refrigeration cycle and then returning to the refrigeration cycle of the first refrigerant via the first heat exchanger.

Embodiment of the present invention by using the compressor of the secondary refrigerant in the initial operation of the primary refrigerant to shorten the operation normalization time, while preventing the vicious cycle that the dual refrigeration system does not operate properly due to the abnormal operation of the primary refrigerant. This can solve the installation area problem during gas injection by injecting the primary refrigerant in the liquid phase.

1 is a view schematically showing a natural gas liquefaction system as an example of a conventional two-way refrigeration system.
FIG. 2 is a view schematically illustrating only a precooling process in the natural gas liquefaction system illustrated in FIG. 1.
3 is a view schematically showing a binary refrigeration system according to an embodiment of the present invention.
FIG. 4 is a view schematically illustrating a flow in the second refrigerant circulation supply unit and the first refrigerant return circulation supply unit of the primary refrigerant in the binary refrigeration system shown in FIG. 3.
FIG. 5 is a view schematically showing the flow of the primary refrigerant circulation supply unit of the primary refrigerant in the binary refrigeration system shown in FIG.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

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

3 is a view schematically showing a binary refrigeration system of a natural gas liquefaction system according to an embodiment of the present invention.

Natural gas liquefaction system is a representative example of the binary refrigeration system and method of the present invention can be applied.

As shown in FIG. 3, in the two-way refrigeration system according to the present embodiment, the first heat exchanger 100 and the first heat exchanger 100 to which the first refrigerant for circulation of the cooling target fluid is circulated are supplied. The first refrigerant circulating supply unit 200 for circulating and supplying the refrigerant by compression, the secondary heat exchanger circulated and supplied with the second refrigerant for cooling the cooling target fluid, and the second refrigerant being circulated and supplied with the second refrigerant by the secondary heat exchanger. The first refrigerant heat-exchanged in the second refrigerant circulation supply unit and the primary heat exchanger 100 is compressed and cooled in the second refrigerant circulation supply unit and then supplied to the primary heat exchanger 100 to be heat-exchanged with the fluid to be cooled and then the first refrigerant. The first refrigerant return circulation supply unit 500 to return to the refrigerant circulation supply unit 200 is included.

The natural gas liquefaction process generally refers to a process of liquefying a fluid to be cooled by purifying a gas in a gas field and cooling it from about room temperature to about -160 ° C or less using a refrigerant.

The binary refrigeration system according to an embodiment of the present invention may be applied to a propane precooled mixed refrigerant process (C3MR process), which is one of the most used processes among natural gas liquefaction processes. In addition, the present embodiment can be applied to a liquefaction plant, such as a pilot plant, which requires starting and stopping, and the propane precooled mixed refrigerant process is formed by two refrigerant cycles. However, these processes can be designed and manufactured in various structures under the same name.

However, the natural gas liquefaction system is an example to which the dual refrigeration system of the present invention can be applied as described above, and the binary refrigeration system of the present invention can be generally applied to a binary refrigeration system requiring cryogenic refrigeration.

As shown in FIG. 3, in the natural gas liquefaction system according to an embodiment of the present invention, when the first refrigerant for cooling the cooling target fluid is circulated and supplied, the cooling target is exchanged through the first heat exchanger 100. The fluid is precooled.

The primary heat exchanger 100 may be used as a kettle type heat exchanger, for example, it may be implemented as a Shell & Tube, Flate-fin heat exchanger.

In this embodiment, the temperature of the pre-cooled natural gas may be about -30 to -40 ℃.

The pre-cooled natural gas is liquefied in the main cooling process through heat exchange with the second refrigerant circulated and supplied through the second refrigerant circulation supply unit 300 in the secondary heat exchanger.

The natural gas liquefaction process by the first refrigerant and the second refrigerant as described above is performed when the binary refrigeration system is operating normally.

However, during the initial operation of the binary refrigeration system, such a natural gas liquefaction process is difficult to occur immediately.

In the initial operation of the binary refrigeration system, the amount of the first refrigerant introduced into the system is insufficient, and it takes a certain time for the precooling process to operate normally. Disturb. Therefore, there is a need for a sufficient first refrigerant gas securing method for the operation of the first refrigerant compression system for a predetermined time during the initial operation of the primary refrigerant.

To this end, the existing binary refrigeration system has been installed a large-capacity gas storage tank for the first refrigerant gas injection, or a separate vaporizer for vaporizing the liquid first refrigerant.

However, this was not efficient in terms of equipment cost and equipment area due to the expansion of the unit.

To this end, in the present embodiment, in order to avoid additional unit facilities and to utilize the existing system, the first refrigerant is injected into the liquid phase, and the second refrigerant is circulated and cooled in a gas state in the second refrigerant circulation supply unit to return to the first refrigerant circulation supply unit 200. The first refrigerant return circulation supply unit 500 is proposed.

The first refrigerant return circulation supply unit 500 of the present embodiment is provided in a line of the first refrigerant circulation supply unit 200 to induce the first refrigerant heat exchanged in the primary heat exchanger 100 to be supplied to the second refrigerant circulation supply unit. The third three-way valve is provided in the first three-way valve 510 and the second refrigerant circulation supply unit to induce the first refrigerant heat exchanged in the primary heat exchanger 100 to be supplied to the first refrigerant circulation supply unit 200. Valve 530.

In addition, the first refrigerant return circulation supply unit 500 is provided in the line of the second refrigerant circulation supply unit 300 and the first refrigerant supplied to the second refrigerant circulation supply unit 300 is supplied to the second receiver tank of the second refrigerant circulation supply unit. And a second three-way valve 520 which induces to be bypassed without being stored.

3 and 4 schematically illustrate the flow of the first refrigerant through the first refrigerant return circulation supply unit 500.

3 and 4, during initial operation of the binary refrigeration system, the first refrigerant is injected into the liquid phase into the first receiver tank 240 and completely vaporized at the rear end of the first expansion valve. The first refrigerant in the fully vaporized gas state flows to the first branch line 501 by the first three-way valve 510 and the second refrigerant circulation supply unit 300 is also introduced. The first refrigerant introduced into the second refrigerant circulation supply unit 300 is compressed and cooled while passing through the second refrigerant circulation, and the second refrigerant which bypasses the second receiver tank by the second three-way valve 520. Flows to line 502. The first refrigerant reaching the flow path of the second refrigerant through the second branch line 502 is introduced into the first refrigerant circulation supply unit 200 through the third branch line 503 by the third three-way valve 530. do.

The first refrigerant circulation supply unit 200 is installed at the rear end of the primary heat exchanger 100 to suction the first suction drum 210 and the first refrigerant to suck the first refrigerant discharged from the primary heat exchanger 100. A first compression system 220 for suction and compression, a first condenser 230 for condensing the compressed first refrigerant, a first receiver tank for accumulating the condensed first refrigerant, and a first refrigerant accumulated in the first receiver tank It includes a first expansion valve 260 for circulating supply to the primary heat exchanger (100).

According to the present embodiment, the first refrigerant circulation supply unit 200 adjusts the amount of the first refrigerant injected into the first receiver tank 240 and the first expansion valve 260 into which the first refrigerant is injected in the liquid phase. Valve 250, a first separator 270 that separates the first refrigerant circulated in the first heat exchanger into a gas and a liquid, a gate valve 281 that controls the injection of the separated gas into the suction drum, a separated gas Solenoid valve to regulate the injection of the first compression system 220 into the first compression system 220, pressure regulator 282 to adjust the pressure of the first refrigerant injected from the suction drum into the first compression system 220 and the first from the suction drum It further includes a control valve 283 that regulates the injection of the first refrigerant into the compression system 220.

Hereinafter, an operating state of the first refrigerant circulation supply unit 200 according to the present embodiment will be briefly described.

The first refrigerant injected into the liquid phase into the first receiver tank is vaporized at the first expansion valve 260 through the needle valve 250 whose valve trajectory is adjusted so as to be completely vaporized after the first expansion valve 260. . The vaporized first refrigerant is introduced into the first suction drum 210 via the first refrigerant return circulation supply unit 500. The gate valve 281 and the control valve 283 are locked until a sufficient amount of the first refrigerant is filled in the first suction drum 210. When sufficient first refrigerant is charged in the first suction drum 210, the pressure regulator 282 is adjusted to the inlet pressure condition, and the control valve 283 is gradually opened to introduce the first refrigerant into the first refrigerant compression system. The compression cooling process of the first refrigerant is made. After the compression cooling, the first refrigerant having passed through the primary heat exchanger 100 is gas-liquid separated by the first separator 270, and the gas part flows into the first suction drum 210 or the first refrigerant compression system.

By comparing the pressure in the first suction drum 210 with the pressure in the separator, when the pressure in the first suction drum 210 is high, the gate valve 281 is closed and the solenoid valve is opened, which is separated by the first separator 270. The gas is introduced into the first refrigerant compression system. This is the early stage of operation of a binary refrigeration system. When the amount of the first refrigerant introduced from the first separator 270 is insufficient, the first refrigerant gas is additionally supplied from the first suction drum 210.

On the other hand, when the pressure of the first separator 270 is high or the same pressure, the solenoid valve is closed and the gate valve 281 is opened, so that all of the gas separated from the first separator 270 is transferred to the first suction drum 210. It is introduced and then introduced into the first refrigerant compression system.

The second refrigerant circulation supply unit is installed at the rear end of the second heat exchanger to supply the first refrigerant or the second refrigerant from the second suction drum 310 and the second suction drum 310 to suck the first refrigerant or the second refrigerant. A second compression system 320, an intercooler 330 in which the compressed first or second refrigerant is cooled, and a second receiver tank 340 that accumulates the cooled second refrigerant.

The second refrigerant circulation supply unit further includes a check valve 350 to prevent the refrigerant from flowing back to the intercooler 330 and a discharge port 380 for discharging the first refrigerant remaining in the second refrigerant circulation supply unit.

Hereinafter, the operating state of the second refrigerant circulation supply unit according to the present embodiment will be briefly described.

When the precooling system of the first refrigerant reaches normal operation, introduction of the first refrigerant into the second refrigerant circulation supply unit 300 by the first three-way valve 510 is terminated.

When different types of refrigerants are used as the first refrigerant and the second refrigerant, the first refrigerant that may remain in the second refrigerant circulation supply unit 300 may have the outlet 380 prior to introducing the second refrigerant into the system. All must be discharged.

In addition, since the first and second refrigerants have different properties, the degree of cooling of the intercooler 330 should be adjusted by determining a condensation point according to pressure and temperature according to the type of refrigerant introduced into the system.

In the present embodiment, it is preferable to use propane as the first refrigerant and mixed refrigerant as the second refrigerant, but the type of the refrigerant is not limited thereto. An appropriate refrigerant may be selected in consideration of the type of the fluid to be supplied, the desired degree of cooling, the cooling efficiency, and the like.

According to an aspect of the present invention, in the two-way cooling system through the two or more refrigeration system, in order to normalize the operation of the refrigeration cycle of the first refrigerant using a refrigeration cycle other than the refrigeration cycle of the refrigerant, the primary heat exchanger (100) And a part of the first refrigerant heat exchanged in the C) is cooled in the other refrigeration cycle and then returned to the refrigeration cycle of the first refrigerant via the first heat exchanger (100).

As described above, in a dual cooling system using two or more refrigeration cycles, the normal operation of the system is achieved by utilizing the refrigerating cycle of the second refrigerant and injecting the first refrigerant into the liquid phase during the initial operation of the system. In addition to being able to reduce the volume of the equipment, it is possible to reduce the volume of the equipment by increasing the space utilization, and prevent the addition of additional unit equipment.

The binary refrigeration system of the present invention has high space utilization by injecting the first refrigerant into liquid phase, and thus can be effectively applied to a refrigeration system, for example, a cold room, to be installed in a limited space.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

100: primary heat exchanger
200: first refrigerant circulation supply unit
210: first suction drum
220: first compression system
230: first capacitor
240: first receiver tank
250: needle valve
260: first expansion valve
270: first separator
281: Gate Valve
282: Pressure Regulator
283: control valve
300: second refrigerant circulation supply unit
310: second suction drum
320: second compression system
330: intercooler
340: second receiver tank
350: check valve
380: outlet
500: first refrigerant return circulation supply unit
501: first branch line
502: second branch line
503: third branch line
510: first three-way valve
520: the second three-way valve
530: third three-way valve

Claims (10)

A primary heat exchanger through which a first refrigerant for cooling the fluid to be cooled is circulated and supplied;
A first refrigerant circulation supply unit configured to compressively cool and supply the first refrigerant to the primary heat exchanger;
A secondary heat exchanger through which a second refrigerant for cooling the fluid to be cooled is circulated and supplied;
A second refrigerant circulation supply unit configured to circulate and supply the second refrigerant by compression cooling the secondary heat exchanger; And
The first refrigerant heat-exchanged in the primary heat exchanger is compressed and cooled in the second refrigerant circulation supply unit and then supplied to the primary heat exchanger again to exchange heat with the cooling target fluid to return to the first refrigerant circulation supply unit. A binary refrigeration system comprising a first refrigerant return circulation supply. The method of claim 1, wherein the first refrigerant return circulation supply unit
A first three-way valve provided in a line of the first refrigerant circulation supply unit to guide the first refrigerant heat-exchanged in the primary heat exchanger to the second refrigerant circulation supply unit; And
And a third three-way valve provided in a line of the second refrigerant circulation supply unit to guide the first refrigerant exchanged in the primary heat exchanger to the first refrigerant circulation supply unit. The method of claim 1, wherein the first refrigerant return circulation supply unit
A second three-way valve provided in a line of the second refrigerant circulation supply unit to guide the first refrigerant supplied to the second refrigerant circulation supply unit to be bypassed without being stored in the second receiver tank of the second refrigerant circulation supply unit; Binary refrigeration system further comprising. The method of claim 1, wherein the first refrigerant circulation supply unit
A first suction drum installed at a rear end of the primary heat exchanger to suck the first refrigerant discharged from the primary heat exchanger;
A first compression system for sucking and compressing the first refrigerant;
A first condenser for condensing the compressed first refrigerant;
A first receiver tank for accumulating the first refrigerant condensed; And
And a first expansion valve for circulating and supplying the first refrigerant accumulated in the first receiver tank to the primary heat exchanger. The method of claim 4, wherein the first refrigerant circulation supply unit
A needle valve controlling an amount of the first refrigerant injected into the first expansion valve;
A first separator separating the first refrigerant circulated through the primary heat exchanger into a gas and a liquid;
A gate valve for controlling injection of said separated gas into said first suction drum;
A solenoid valve that regulates injection of the separated gas into the first compression system;
A pressure regulator for regulating the pressure of the first refrigerant injected into the first compression system from the first suction drum; And
Further comprising a control valve for regulating the injection of a first refrigerant from said first suction drum to said first compression system,
The first refrigerant is a binary refrigeration system, characterized in that the liquid injection into the first receiver tank. The method of claim 1, wherein the second refrigerant circulation supply unit
A second suction drum installed at a rear end of the secondary heat exchanger to suck the first refrigerant or the second refrigerant;
A second compression system supplied with the first refrigerant or the second refrigerant from a second suction drum;
An intercooler in which the compressed first or second refrigerant is cooled; and
And a second receiver tank for accumulating the cooled second refrigerant. The method of claim 6, wherein the second refrigerant circulation supply unit
A check valve to prevent refrigerant from flowing back into the intercooler; And
And a discharge port for discharging the first refrigerant remaining in the second refrigerant circulation supply unit. 8. The method according to any one of claims 1 to 7,
The first refrigerant uses propane, the second refrigerant is a mixed refrigerant, characterized in that using a mixed refrigerant. 8. The method according to any one of claims 1 to 7,
The cooling fluid is a binary refrigeration system, characterized in that the natural gas. In a binary refrigeration system having two or more refrigeration cycles, a part of the first refrigerant heat exchanged in the primary heat exchanger may be utilized by using a refrigeration cycle other than the refrigeration cycle of the corresponding refrigerant to normalize operation of the refrigeration cycle of the first refrigerant. Operating the dual refrigeration system after cooling in the other refrigeration cycle and returning to the refrigeration cycle of the first refrigerant through the first heat exchanger.

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