JP3370464B2 - Heat exchange equipment for gas liquefaction plant - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat exchange device used in a liquefaction section of a gas liquefaction plant.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a gas liquefaction plant for liquefying natural gas includes a pre-cooling section 51 for pre-cooling natural gas with a single-component refrigerant and a multi-component system for pre-cooling natural gas. And a liquefaction section 52 for further cooling and liquefying with the refrigerant (Japanese Examined Patent Publication No. 61-
55,024).

Conventionally, a humpson type heat exchange device 53 is used in the liquefaction section 52. The heat exchange device 53 has, for example, two cooling stages 54 and 55 of different temperature ranges in a vertical type. It is placed vertically in the cold storage container. Each of the cooling stages 54 and 55 is provided with a plurality of wound tubes wound up in a spiral shape, and these wound tubes are arranged on the lower side so that the cold end is located above the warm end. The natural gas and the high-pressure multi-component refrigerant, which are the fluid to be cooled, are supplied from. The heat exchange device 53 causes the fluid to be cooled to flow from the lower side to the upper side in the wound tube, while the cooling stages 54.5
By dropping the low-pressure multi-component refrigerant (cooling fluid) from above 5, the fluid to be cooled is cooled by heat exchange with the low-pressure multi-component refrigerant.

[0004]

However, in the above-mentioned conventional heat exchange device 53, it is necessary to increase the winding amount of the wound tube in order to sufficiently cool the fluid to be cooled, and as a result, the heat exchange device 53 is expensive. As a result, there is a problem that the risk of working in high places during construction and maintenance increases, and that the wound tube limits the degree of freedom in designing the shape and height of the heat exchange device. There is.

Further, when an accident or a failure occurs during the operation of the heat exchange device 53, it becomes necessary to carry out a reduction operation, or when a plan for capacity enhancement occurs, a Hampson heat exchanger to be applied independently for each series is Since it is necessary to adjust the flow rate of the fluid to be cooled flowing in the wound tube and the dropping amount of the multi-component refrigerant dropped in each cooling stage 54/55, it is difficult to adjust the heat exchange capacity. is there. Further, when the heat exchange device 53 is stopped due to a failure or the like, the low-temperature condensate flow existing in the upper cold end flows into the lower warm end, so that the warm end side pipe is also formed of a low temperature material. However, there is also a problem that equipment costs increase.

Therefore, the first object of the present invention is to provide a heat exchange device which can lower the heat exchange device 53 and can easily adjust the heat exchange capacity. A second object of the present invention is to provide a heat exchange device which can increase the degree of freedom in design and can reduce the facility cost by eliminating the need for a low temperature material used for the warm end side pipe.

[0007]

In order to solve the above-mentioned problems, the heat exchange device according to the present invention is a gas liquefaction plant comprising a pre-cooling section with a single-component refrigerant and a liquefaction section with a multi-component refrigerant. It is applied and has the following features.

Namely, the heat exchange device of claim 1, using a plate fin heat exchanger liquefied section, and, dividing the plate-fin heat exchanger, the cooling temperature to a predetermined range in a cold container It is characterized by being arranged vertically so that the warm end is located above the cold end. Further, in the heat exchange device according to the first and second aspects, it is desirable that a plurality of plate fin heat exchangers are provided in parallel in the cold insulation container.

[0009]

According to the structure of claim 1, since the plate fin heat exchanger has a large heat exchange rate per unit volume, the height can be made lower than that of the Hampson type heat exchange device, and work at high places can be performed. It is supposed to be able to reduce the risk of.
Also, since the plate fin heat exchanger is installed vertically so that the warm end is located above the cold end, the condensate flow existing at the cold end is free-falling when the operation is stopped. It does not flow into the part and bump.

Further, since the Plate fin heat exchangers cooling temperature of the cooling fluid is provided in the form of divided every predetermined range, for example, even when there are restrictions on the shape and volume of the cold chamber, the plate-fin heat exchanger It is possible to easily deal with this by changing the arrangement of the vessels, and it is possible to increase the degree of freedom in design. Also, unlike the Hampson type heat exchange device in which the cold end is located above the warm end, when the operation is stopped, the condensate flow at the cold end does not flow into the warm end, so It is no longer necessary to use a low temperature material for the warm end side pipe, and as a result, it is possible to reduce the usage amount of the low temperature material and reduce the equipment cost.

Further, according to the structure of claim 1 , plate fin heat exchangers can be provided in parallel,
Since these plate fin heat exchangers perform heat exchange independently, it is easier to stop or add a predetermined number of plate fin heat exchangers as compared to the Hampson type, which is applied individually to one series. It is possible to adjust the heat exchange capacity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The heat exchange device according to the present embodiment is used in a liquefaction section of a gas liquefaction plant including a pre-cooling section using a single-component refrigerant and a liquefaction section using a multi-component refrigerant. The heat exchange device cools the gas flow of natural gas or the like in three stages as shown in FIG. 3 by heat exchange with the low-pressure multi-component refrigerant flow. The cooling stage in the high temperature range is arranged above the cooling stage in the low temperature range so that the condensate flow existing in the cooling stage in the temperature range does not flow to the cooling stage in the high temperature range due to free fall. There is.

The cooling stage described above is formed by a plate fin heat exchanger having a large heat exchange rate per unit volume, and the plate fin heat exchanger has a plurality of wave-like formations as shown in FIG. Fins 38 and flat plate 39
Are alternately laminated, and the adjacent flat plates 39 are so arranged that the fluid to be cooled and the low-pressure multi-component refrigerant are in contact with each other through the flat plates 39.
The cooling fluid (natural gas, high-pressure vapor flow of multi-component refrigerant or high-pressure condensate flow) paths and low-pressure multi-component refrigerant flow paths are alternately arranged between 39.

The structure of the heat exchanging device having the plate fin heat exchanger will be specifically described.
As shown in FIG. 1, a plurality of first plate fin heat exchangers 1 ... Setting a first cooling stage and a second cooling stage, and a plurality of second plate fin heat exchangers 24 setting a third cooling stage.
24 and 24 are provided in parallel in the cold storage container 32. As a result, the heat exchanging device is operated by each heat exchanger 1 ...
Since 24 heat exchangers independently perform heat exchange, it is possible to easily adjust the heat exchange capacity by stopping or adding specific heat exchangers 1 ... 24 24. Further, the first plate fin heat exchanger 1 ... And the second plate fin heat exchangers 24, 24 are vertically installed such that the warm end is located above the cold end, and when the cold stop is performed, The condensate stream present at the end is prevented from flowing to the warm end by free fall.

The first plate fin heat exchanger 1 ...
, The cooled fluid passage is divided into at least three kinds of fluid, and the cooled fluid passage of the third division is internally provided with a partition wall so as to be an independent upper and lower fluid passage. The first cooling stage, which has the highest temperature range, is the third
The second cooling stage, which is located above the cooled fluid passage of the section and has an intermediate temperature range, is located below the cooled fluid passage of the third section.

As shown in FIG. 3, a pipe 4 is connected to the upper end of the cooled fluid passage of the first section, and a high-pressure condensate flow of the multi-component refrigerant is supplied through the pipe 4. It has become so. On the other hand, a pipe 5 is connected to the upper end of the fluid passage to be cooled in the second section, and the high pressure vapor flow of the multi-component refrigerant is supplied via the pipe 5. Then, these high-pressure multi-component refrigerants travel downward in the cooled fluid paths set in the first section and the second section of the first plate fin heat exchanger 1 ... From the first cooling stage to the second cooling stage, respectively. It is supposed to do.

Pipes 6 and 7 are connected to the upper and lower ends of the cooled fluid passage of the third section in the first cooling stage, respectively, and the pipe 6 uses precooled natural gas as a vapor flow. It is designed to be supplied to the first cooling stage. The pipe 7 is connected to the gas-liquid separator 8,
The natural gas that has passed through the first cooling stage is supplied to the gas-liquid separator 8.

The gas-liquid separator 8 is connected to the upper end of the fluid passage to be cooled in the second cooling stage via a pipe 9 so as to supply the vapor stream of natural gas after gas-liquid separation. ing. A flush valve 23 is connected to the lower end of the cooled fluid passage of the second cooling stage via the pipe 11.
The flash valve 23 is connected to the second plate fin heat exchangers 24, 24 via the pipe 19.

The second plate fin heat exchanger 24.
24 are arranged in parallel below the first plate fin heat exchangers 1 ... And constitute a third cooling stage having the lowest temperature range. The cooled fluid passages of the second plate fin heat exchangers 24, 24 are divided into two types of fluids, and the above-described pipe 19 is provided at the upper end of the cooled fluid passage of the first division. It is connected and supplied with natural gas. On the other hand, at the upper end of the cooled fluid path of the second section,
The lower end of the fluid passage to be cooled in the second section of the first plate fin heat exchanger 1 ... Is connected via the pipe 10 ...
The high-pressure vapor stream of the multi-component refrigerant from the plate fin heat exchangers 1 ... Is supplied. And this second
The lower end of the cooled fluid passage of the section is connected to the flush valve 25 via the pipe 17, and the flush valve 2
5 is connected to a gas-liquid separator 26 via a pipe 18.

As shown in FIG. 1, the gas-liquid separator 26 is a horizontal H-shaped tank, and has an upper container 26a, an intermediate container 26b, and a lower container 26c. ing. The upper accommodating portion 26a has a hollow cylindrical member whose both ends are hermetically sealed, and is horizontally installed. Inside the upper accommodating portion 26a, an injection member having a large number of injection holes is inserted. ing. The injection member is connected to the pipe 18, and a flow obtained by expanding the high-pressure vapor flow of the multi-component refrigerant by the flash valve 25 described above (referred to as a second low-pressure multi-component refrigerant flow) is inside the upper accommodation portion 26a. It is designed to be released.

At an intermediate position of the upper accommodation portion 26a,
The upper end of an intermediate accommodating portion 26b in which a hollow cylindrical member is vertically installed is connected. To the lower end of the intermediate accommodating portion 26b, a lower accommodating portion 26c having a hollow cylindrical member whose both ends are sealed in an airtight state is horizontally connected, and the lower accommodating portion 26c is connected.
The upper housing portion 26a and the upper housing portion 26a are in communication with each other via the intermediate housing portion 26b. And this gas-liquid separator 26 is
The second low-pressure multi-component refrigerant flow of gas-liquid mixed phase is discharged from the injection member and the condensed liquid flow is stored in the lower storage portion 26c, while the vapor flow is stored in the upper storage portion 26a, thereby separating the gas-liquid. It is like this.

A pipe 20 is connected to the upper accommodation portion 26a, and a pipe 21 is connected to the lower accommodation portion 26c. As shown in FIG. 3, these pipes 20 and 21 are connected to a mixer 28 provided in the second plate fin heat exchangers 24 and 24, and the mixer 28 is
The vapor stream of the second low-pressure multi-component refrigerant stream and the condensate stream of the second low-pressure multi-component refrigerant stream separated in the gas-liquid separator 26 are adapted to be mixed.

The above mixer 28 is built in the low pressure multi-component refrigerant flow path of the second plate fin heat exchanger 24, 24, and the upper end of this low pressure multi-component refrigerant flow path is cooled by the pipe 16 It is connected to the liquid separator 2. The gas-liquid separator 2 is
As shown in FIG. 2, similarly to the gas-liquid separator 26 described above, the upper accommodation portion 2a in which the injection member 27 is installed and the intermediate accommodation portion 2 are provided.
b and a lower accommodation portion 2c, and an upper accommodation portion 2a.
A pipe 16, a pipe 15, and a pipe 13 are connected to.

As shown in FIG. 3, the pipe 15 is connected to a flash valve 29. The flash valve 29 is connected to the first section of the first plate fin heat exchanger 1 ... It is connected to the lower end of the cooling fluid path. As a result, the gas-liquid separator 2 is supplied with the flow obtained by expanding the high pressure condensed liquid flow of the multi-component refrigerant from the first plate fin heat exchanger 1 ... The second plate fin heat exchanger 24.
The low-pressure multi-component refrigerant stream is supplied via the pipe 16. Here, the above two fluids are the gas-liquid separator 2
The components are uniformly mixed therein to form a first low-pressure multi-component refrigerant flow.

The upper container 2a of the gas-liquid separator 2 is
The first plate fin heat exchanger 1 ... Is connected to a mixer 30 built in the lower end via a pipe 13. Further, the lower container 2 c of the gas-liquid separator 2 is connected to the mixer 30 via the pipe 12. As a result, the mixer 30 is supplied with the first low-pressure multi-component refrigerant flow from which the gas-liquid has been separated in the gas-liquid separator 2 via the pipes 13 and 12.

The above mixer 30 is connected to the lower end of the low pressure multi-component refrigerant flow path of the first plate fin heat exchangers 1 ... and cools the first low pressure multi-component refrigerant flow produced by mixing as a cooling fluid. It is supposed to rise. And
A pipe 31 is connected to the upper end of the low-pressure multi-component refrigerant flow path, and the first low-pressure multi-component refrigerant flow passing through the low-pressure multi-component refrigerant flow path of the first plate fin heat exchanger 1 ...
It is designed to be discharged through 1.

The operation of the heat exchange device having the above structure will be described. As shown in FIG. 3, the gas-liquid separator 3
The high-pressure condensate flow of the multi-component refrigerant in which the gas-liquid is separated by 3, the high-pressure vapor flow of the multi-component refrigerant, and the natural gas pre-cooled in the pre-cooling section are each section of the first plate fin heat exchanger 1. By being supplied to the upper ends of the cooled fluid passages, the cooled fluid passage of the first cooling stage descends as the cooled fluid. Then, the high-pressure condensate flow of the multi-component refrigerant and the high-pressure vapor flow of the multi-component refrigerant that have passed through the first cooling stage descend the second cooling stage of the first plate fin heat exchanger 1 ... Will be discharged from the lower end of. On the other hand, the natural gas that has passed through the first cooling stage is supplied to the upper end of the second cooling stage as a vapor flow of natural gas after the gas-liquid separator 8 separates the gas and liquid, and then descends the second cooling stage. Will be discharged from the lower end.

The high-pressure vapor stream of the multi-component refrigerant and natural gas discharged from the second cooling stage constitute the second cooling stage.
It is supplied to the upper end of the cooled fluid passage of the plate fin heat exchangers 24, 24, descends the cooled fluid passage, and is discharged from the lower end. After this, the high pressure vapor flow of the multi-component refrigerant
It is adiabatically expanded and cooled by the flash valve 25,
It becomes the second low-pressure multi-component refrigerant flow, and after the gas-liquid separator 26 separates the gas-liquid, it is supplied to the lower ends of the refrigerant paths of the second plate fin heat exchangers 24, 24 while being mixed by the mixer 28. It will be.

The above-mentioned second low-pressure multi-component refrigerant flow is a high-pressure vapor flow of multi-component refrigerant that rises in the low-pressure multi-component refrigerant passage of the second plate fin heat exchanger 24, 24 and descends in the fluid passage to be cooled. And natural gas to each second plate fin heat exchanger 2
In 4/24, they will be cooled independently. Then, the second low-pressure multi-component refrigerant flow is discharged from the upper ends of the second plate fin heat exchangers 24, 24 and supplied to the gas-liquid separator 2.

A high-pressure condensate flow of the multi-component refrigerant which has passed through the fluid passage to be cooled of the first plate fin heat exchanger 1 ... Is obtained in the gas-liquid separator 2 by adiabatic expansion by the flash valve 29. Fluid is also supplied, and the first low-pressure multi-component refrigerant flow obtained by mixing the components is the gas-liquid separator 2
After the gas-liquid is separated by the above, it is supplied to the lower end of the low pressure multi-component refrigerant flow path of the first plate fin heat exchanger 1 ... While being mixed by the mixer 30. Then, the first low-pressure multi-component refrigerant flow rises in the low-pressure multi-component refrigerant passages of the second cooling stage and the first cooling stage of the first plate fin heat exchanger 1 ... And descends in the cooled fluid passage. The high-pressure vapor stream of natural gas and multi-component refrigerant and the high-pressure condensate stream of multi-component refrigerant are cooled independently in each first plate fin heat exchanger 1.

Thus, as shown in FIG. 1, the heat exchange apparatus of this embodiment has the first plate fin heat exchanger 1 ... And the second plate fin heat exchanger 24 ... Used in the liquefaction section of the gas liquefaction plant. 24 and the first plate fin heat exchanger 1 ... And the second plate fin heat exchanger 24 so that the warm end is located above the cold end.
The first feature is that 24 is installed vertically in the cool container 32.

As a result, since the first plate fin heat exchanger 1 ... And the second plate fin heat exchangers 24, 24 have a large heat exchange rate per unit volume, compared to the Hampson type heat exchanger. The height can be lowered and the risk of working at height can be reduced. Further, the first plate fin heat exchanger 1 ... And the second plate fin heat exchanger 24, 24 so that the warm end is located above the cold end.
Is installed vertically, so that when the operation is stopped, the condensate flow existing at the cold end does not flow to the warm end by free fall and bumping does not occur.

Further, the heat exchange device of this embodiment has a second feature that it is provided with the first plate fin heat exchangers 1 ... And the second plate fin heat exchangers 24, 24 in parallel. ing. As a result, the first plate fin heat exchanger 1 and the second plate fin heat exchangers 24, 24, which are provided in parallel, perform heat exchange independently of each other, so that they are independently applied to one series. compared to,
While responding to an accident or failure, for example, by stopping a predetermined number of the first plate fin heat exchangers 1 ... Or by planning to expand the plant capacity, by adding a predetermined number, the heat exchange capacity can be easily increased. Can be adjusted.

Further, the heat exchange device of the present embodiment has the first plate fin heat exchanger 1 to which the fluid to be cooled and the refrigerant are supplied.
... and the second plate fin heat exchangers 24, 24 are provided in the vertical cold storage container 32 in a form in which the cooling temperature is divided into predetermined ranges, and the hot end is vertically positioned so as to be located above the cold end. The first plate fin heat exchanger 1 ... and the second plate fin heat exchanger 24
It has as a feature of.

As a result, the cooling temperature of the fluid to be cooled is divided into predetermined ranges by the first plate fin heat exchanger 1 ... And the second plate fin heat exchangers 24, 24. Even if there are restrictions on the shape and volume, the first plate fin heat exchanger 1 ... and the second plate fin heat exchanger 1 ...
By changing the arrangement of the plate fin heat exchangers 24, 24, it is possible to easily cope with this, and it is possible to increase the degree of freedom in design.

Further, unlike the Hampson type heat exchange device in which the cold end is located above the warm end, the condensate flow at the cold end does not flow into the warm end when the operation is stopped.
Therefore, it is not necessary to form the warm end side pipe located above with the low temperature material, and as a result, it is possible to reduce the usage amount of the low temperature material and reduce the facility cost. In the present embodiment, the case where the number of cooling stages is three has been described, but there may be a case where the first cooling stage and the second cooling stage in FIG. 3 are combined into a total of two cooling stages.

[0037]

As described above, the present invention provides a plate fin heat exchanger used in a liquefaction section in a gas liquefaction plant comprising a pre-cooling section using a single-component refrigerant and a liquefaction section using a multi-component refrigerant, The warm end
Since it is vertically installed in the cold storage container so as to be located above the cold end , the height can be made lower than that of the Hampson type heat exchange device, and the risk of working in high places can be mitigated.

Further, according to the present invention, as described above, the cooling temperature is divided into predetermined ranges, and the plate fin heat exchanger is vertically arranged so that the hot end is located above the cold end. Since the configuration is arranged, even if there are restrictions on the shape or volume of the cold insulation container, it is possible to easily cope with it by changing the arrangement of the plate fin heat exchanger, increasing the degree of freedom in design. The effect is that it is possible.

Further, like the Hampson type heat exchange device in which the cold end is located above the warm end, the condensate flow at the cold end flows into the warm end by free fall when the operation is stopped. Therefore, there is no need to use a low temperature material for the upper warm end side pipe, and as a result, it is possible to reduce the usage amount of the low temperature material and reduce the facility cost.

Further, as described above, according to the present invention, a plurality of plate fin heat exchangers are applied in parallel as compared with the Hampson type which is independently applied to one series, so that it is easy to deal with an accident or the like. In addition, it is possible to reduce the amount of heat, and by adding a predetermined number of heat exchangers, it is possible to finely adjust the heat exchange capacity.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a heat exchange device, in which (a) is a side view and (b) is a front view.

FIG. 2 is a front view of the gas-liquid separator 2 shown in the side view of FIG.

FIG. 3 is an explanatory diagram showing a fluid flow of a heat exchange device.

FIG. 4 is a perspective view of a plate fin heat exchanger.

FIG. 5 is a process diagram of a gas liquefaction plant.

[Explanation of symbols]

1st plate fin heat exchanger 2 gas-liquid separator 24 Second plate fin heat exchanger 26 gas-liquid separator 32 Cold container

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Claims (2)

(57) [Claims] 1. A heat exchanger of a gas liquefaction plant comprising a pre-cooling section with a single-component refrigerant and a liquefaction section with a multi-component refrigerant, wherein a plate fin heat exchanger is used in the liquefaction section, and A gas characterized in that the plate fin heat exchanger is provided in a cool container in a form in which the cooling temperature is divided into predetermined ranges, and is arranged vertically so that the hot end is located above the cold end. Heat exchange equipment for liquefaction plants. 2. The heat exchange device for a gas liquefaction plant according to claim 1 , wherein a plurality of the plate fin heat exchangers are provided in parallel in the cold insulation container.