JP2866939B1 - Liquefied natural gas vaporizer and refrigeration system using the same - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a vaporizer and a refrigeration system capable of sufficiently vaporizing LNG to room temperature and effectively utilizing the cold energy of LNG. SOLUTION: CRE4 for vaporizing LNG is provided in a stratified type cold storage heat storage tank 6 in a number corresponding to the vaporization capacity. CR
A plurality of U-shaped heat transfer tubes 44 with vertical fins are disposed in the lower chamber 30 in the body 24 of E4. Upper chamber 28
Then, the plurality of coiled heat transfer tubes 40 are wound around the cylindrical body 42. Alcohol water is stored as a refrigerant in the stratified-type cold storage heat storage tank 6 and the body 24 to form two circulation systems. The refrigerant in the high-temperature system near normal temperature is
6 is a heat source, and a low-temperature system refrigerant supplies cold heat to the cold heat utilization equipment 14. The position of the temperature interface of the refrigerant is changed according to the fluctuation of the LNG vaporization capacity and the cooling load, and the temperature of the delivered NG is adjusted to be constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied natural gas vaporizer for vaporizing liquefied natural gas and supplying it to consumers as city gas or the like, and a refrigeration system using the same.

[0002]

2. Description of the Related Art Conventionally, liquefied natural gas (hereinafter referred to as "LN
G) is vaporized and supplied to consumers as city gas, and is used for cold storage and frozen food businesses. The present applicant has proposed a cooling and heating system applied to these businesses and a heat exchanger used in the system disclosed in the specification and drawings of Japanese Patent Application No. 8-154779. The cooling system disclosed in the earlier application includes a heat exchanger, a regenerator, and a vaporizer. The heat exchanger has a body, and a substantially U-shaped heat transfer tube is disposed in the body, and LNG is supplied through the heat transfer tube. The body is filled with alcoholic water as a refrigerant, and cold heat from LNG flowing through the heat transfer tubes is exchanged with alcoholic water.

[0003] The heat exchanger is equipped with cold heat utilization equipment through a regenerator,
For example, it is connected to a freezer warehouse. The regenerator has two temperature stratifications, a high-temperature layer and a low-temperature layer, and has a regenerative function utilizing the temperature difference. The alcohol from the heat exchanger is supplied to the cold heat utilization facility through the lower layer of the regenerator, and the cold heat utilization facility is cooled to, for example, −35 ° C. using the cold heat of the alcohol water. Alcohol water from the cold heat utilization facility is returned to the heat exchanger through the upper layer of the regenerator, cooled again in this heat exchanger, and the above-described cooling cycle is repeatedly performed. On the other hand, LNG is vaporized while flowing through the heat exchanger, and the vaporized natural gas (for example, −60 to −3)
The gas whose temperature has been raised to 5 ° C.) is sent to a vaporizer, and further raised to 0 ° C. or higher in the vaporizer and supplied to ordinary households and the like as city gas.

[0004]

However, the cooling and heating system proposed above has the following problems to be solved.

That is, in the above cooling and heating system,
Since a cold storage tank for storing cold heat and a vaporizer for raising the temperature of LNG to 0 ° C. or more are separately required, there is a problem that the cooling system becomes large and the system becomes expensive.

[0006] It is also desired that the heat exchanger can effectively use cold heat near normal temperature such as air conditioning.

A first object of the present invention is to provide a liquefied natural gas vaporizer that can vaporize liquefied natural gas and sufficiently raise the temperature to room temperature, and can effectively use the cold generated at that time. To provide.

A second object of the present invention is to provide a refrigeration system having a large liquefied natural gas vaporizing ability, which can be formed compactly and at low cost.

[0009]

According to the present invention, there is provided a body which extends in a vertical direction and is divided into upper and lower chambers by a partition plate, and a plurality of bodies are disposed in a chamber below the partition plate of the body. U
U-shaped heat transfer tube to which liquefied natural gas is supplied and a U-shaped heat transfer tube attached thereto, and a header arranged near the partition plate and connected to outlet sides of the plurality of U-shaped heat transfer tubes And a cylinder disposed in the chamber above the partition plate of the body so that an annular gap is formed between the body and the body, and housed in the gap between the cylinder and the body, A plurality of coils are wound on the outer peripheral surface in a coil shape, and a lower end thereof includes a coil-shaped heat transfer tube connected to the header. A liquefaction inside the U-shaped heat transfer tube is provided in a chamber below a partition plate of the body. A low-temperature refrigerant for heat exchange with natural gas to vaporize liquefied natural gas is circulated, and in the chamber above the partition plate of the body, the annular gap has heat exchange with natural gas in the coiled heat transfer tube. A liquefied natural gas vaporizer characterized by flowing a normal-temperature refrigerant for raising the temperature of natural gas to normal temperature.

According to the present invention, the low-temperature refrigerant is cooled and the liquefied natural gas is heated by heat exchange between the low-temperature refrigerant and the liquefied natural gas in the U-shaped heat transfer tube in the chamber below the partition plate of the fuselage. To vaporize. The cold heat of the cooled low-temperature refrigerant can be effectively used in low-temperature cold-heat utilization equipment such as a refrigerated warehouse or frozen food. The temperature of the vaporized natural gas will not be higher than the temperature of the cold refrigerant. Evaporated natural gas is
In the chamber above the partition plate of the fuselage, when flowing through the coil-shaped heat transfer tube, it is performed between room temperature refrigerant flowing through the annular gap between the cylinder around which the coiled heat transfer tube is wound and the body. The temperature is raised to room temperature by heat exchange. The room temperature refrigerant is cooled by heat exchange. The cold heat of the normal-temperature refrigerant can be effectively used in, for example, air conditioning.

Further, in the present invention, the low-temperature refrigerant and the normal-temperature refrigerant are the same refrigerant having different temperatures, and the partition plate of the body is provided with a passage for permitting the flow of the refrigerant. When the demand increases, cold replenishment means is provided for replenishing by utilizing the cold heat of the low-temperature refrigerant.

According to the present invention, even if the cold demand near normal temperature becomes larger than the cold generated when the temperature of natural gas rises,
The natural gas can be supplied at a stable temperature even if there is a change in the equilibrium state between the heat load on the cold heat utilization side and the natural gas supply amount because the cold energy of the low-temperature refrigerant can be replenished and dealt with. be able to.

Further, the present invention provides a regenerative heat storage tank containing one or more liquefied natural gas vaporizers, in which a refrigerant stored therein forms approximately three temperature stratifications in the vertical direction. Adjusting means for adjusting the interface position of the temperature stratification of the refrigerant in the regenerative heat storage tank in accordance with a change in the vaporization flow rate of the natural gas and a change in load utilizing cold from the refrigerant. This is a cooling and heating system using a vaporizer.

According to the present invention, the liquefied natural gas vaporizer is housed in the cold storage tank, and the vaporizer and the cold storage tank are integrated, so that the installation space is small. The refrigerant in the cold storage tank forms roughly three temperature stratifications in the vertical direction, and the adjusting means changes the vaporization flow rate of the liquefied natural gas and changes in the load utilizing the cold heat from the refrigerant. Since the position of the interface of the temperature stratification of the refrigerant is adjusted, the cold heat of the liquefied natural gas can be effectively used. Since the body of the liquefied natural gas vaporizer is stored in the refrigerant in the cold storage heat storage tank, it is not necessary to keep the liquefied natural gas vaporizer cool, and the construction cost can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an LNG vaporizer according to the present invention and a cooling and heating system using the same will be described below with reference to the accompanying drawings. FIG. 1 shows an overall configuration of a cooling and heating system according to the present invention, FIG. 2 shows an overall sectional configuration of an LNG vaporizer used in the cooling and heating system of FIG. 1, and FIGS. 3 to 6 show parts of the LNG vaporizer. Shows a typical configuration,
FIG. 7 shows an arrangement in which a plurality of LNG vaporizers are accommodated in the stratified cold storage heat reservoir of FIG.

FIG. 1 shows an embodiment of the present invention.
The overall configuration of a cooling and heating system using an NG vaporizer is shown in a process flow. This cooling / heating system is, for example, a vertical U-tube type LNG vaporizer (hereinafter referred to as Cold) having a vaporization capacity of 1 t / h.
The energy recovery heat exchanger is abbreviated as “CRE”. One or several (up to five) 4 are installed in one stratified cold storage tank 6.
LNG from t / h to 5 t / h can be vaporized to room temperature. In the stratified-type cold storage heat storage tank 6, alcoholic water or the like composed of less than 60% by weight of ethanol and the remaining water is stored as a refrigerant. The refrigerant in the stratified-type cold storage heat layer 6 is
By controlling the extraction position and the return position, the upper part is about 10 ° C., the middle part is about −20 ° C. of −25 to −15 ° C.,
The lower part is divided into cold storage stratifications having three different temperatures depending on the specific gravity so as to be about −35 ° C. of −40 ° C. to −30 ° C. In this cooling / heating system, the same alcoholic water is used for all the refrigerants.

The inlet and outlet pipes of the alcoholic water refrigerant to each CRE 4 are connected to ring pipes 8A, 8B, 8C, 8D. Nozzles 8E, 8F, 8G, 8H, 8I for connection with the refrigerant circulation pumps 10, 12 and the cold heat utilization equipment 14 and the air conditioning equipment 16 are attached to the stratified cold storage heat storage 6, and the stratified cold storage heat storage 6 is provided. Cooling is performed from the lower part of the storage tank 6. This cooling system has two refrigerant circulation lines, a high-temperature system and a low-temperature system.

Refrigerant circulation pump 1 for high-temperature refrigerant circulation line
The high-temperature room-temperature refrigerant of about 10 ° C., which is pressurized at 0, is introduced into each CRE 4 from the ring pipe 8A at a flow rate at which the natural gas (hereinafter, abbreviated as “NG”) outlet temperature becomes equal to or higher than a set value. The cooled refrigerant is extracted from the ring tube 8B,
It is heated again by the heat source equipment such as the air conditioner 16 and circulated.
The NG outlet temperature is detected by a temperature detector 20a for controlling the high-temperature system flow control valve 20. The high-temperature system flow control valve 20 is further controlled by the flow rate detected by the flow rate detector 20b. A high temperature system temperature control valve 22 is provided between the ring pipe 8B and the air conditioner 16 or the like.
It is controlled by a detection output of a temperature detector 22a for detecting a refrigerant outlet temperature from the above.

When the LNG flow rate increases or the load on the air conditioner 16 as a heat source decreases, the high-temperature system flow control valve 20 is further opened or the high-temperature system temperature control valve 22 is throttled, so that NG is reduced to normal temperature. A refrigerant serving as a heat source for raising the temperature is supplied from the stratified cold storage heat storage tank 6 to the CRE 4. Therefore, about 10% of the refrigerant in the body 24 of the CRE 4 is stored in the chamber 28 above the intermediate partition plate 26.
The refrigerant having a relatively high temperature at ℃ flows into the lower chamber 30 through a passage provided in the partition plate 26, and the temperature interface of the refrigerant in the stratified cold storage heat storage tank 6 at 10 ℃ and -20 ℃ rises.

Conversely, when the LNG flow rate decreases or the load on the air conditioner 16 as the heat source increases, the high-temperature system flow control valve 20 is throttled or the high-temperature system temperature control valve 22 is further opened. Is supplied to the stratified cold storage tank 6 from the air conditioner 16 which is a heat source. Therefore, the refrigerant pressurized by the refrigerant circulation pump 12 of the cooling / heating system refrigerant circulation line flows from the lower chamber 30 to the upper chamber 28 through the passage provided in the intermediate partition plate 26 in the body 24, and replenishes cold heat. Is performed. That is, the refrigerant circulation pump 12 has a function as a cooling / heating replenishing means constituting the present invention. At this time, the temperature interface between the temperature of 10 ° C. and −20 ° C. of the refrigerant in the stratified type cold storage heat storage tank 6 is lowered.

On the other hand, the low-temperature system refrigerant pressurized by the refrigerant circulation pump 12 is controlled to a substantially constant flow rate by the low-temperature system flow control valve 32 and introduced into each CRE 4 from the ring tube 8C. Extracted from 8D. A part of the cooled refrigerant is returned to the stratified cold storage heat storage tank 6 by the low-temperature system pressure control valve 34. The refrigerant temperature leaving CRE4 is LN
The temperature is controlled by the low temperature system temperature control valve 36 so as to be always constant irrespective of the flow rate of G. The flow detector 32a for controlling the opening of the low-temperature system flow control valve 32 detects the flow rate of the refrigerant supplied to the cold heat utilization facility 14 from the ring pipe 8D.
The pressure detector 34a for controlling the opening of the low-temperature system pressure control valve 34 detects the pressure of the refrigerant discharged from the ring pipe 8D. The temperature detector 36a for controlling the opening of the low-temperature system temperature control valve 36 detects the temperature of the refrigerant discharged from the ring tube 8D.

Therefore, when the heat load on the cold heat utilization side is constant, when the vaporization flow rate of LNG increases, the refrigerant temperature at the outlet of the CRE 4 decreases, and the low temperature system temperature control valve 36 is throttled, so that the low temperature system flow control valve 32 is opened. -35 ° C and -20
The temperature interface in the stratified-type cold storage heat storage tank 6 of the refrigerant of ° C. rises, and cold heat is stored in the storage tank. Conversely, when the vaporization flow rate decreases, the refrigerant temperature at the outlet of the CRE 4 increases, and the low-temperature system temperature control valve 36 opens.
The temperature interface of the refrigerant at 35 ° C. and −20 ° C. in the stratified-type cold storage heat storage tank 6 is lowered, and the cold in the stratified-type cold storage heat storage tank 6 is used.

When the heat load on the cold-heat utilization side increases or decreases, the amount of the refrigerant returned to the stratified-type regenerative cold storage tank 6 due to a change in the opening of the low-temperature system pressure control valve 34 decreases or increases. The interface descends or rises. As described above, the change in the temperature interface of the refrigerant is caused by the high-temperature system flow control valve 20, the high-temperature system flow control valve 22, and the low-temperature system flow control valve 32.
It is also caused by the operation of the low temperature system temperature control valve 36.
That is, these valves and the low-temperature system pressure control valve 34
The adjusting means constituting the present invention has a function of adjusting the interface position.

The cold heat utilization equipment 14 is associated with, for example, a refrigerated warehouse or a frozen food business, and has a load side temperature control valve 38 so that a refrigerant at −40 to −30 ° C. has an outlet temperature of −25 to −15 ° C. Controls the flow rate. Load side temperature control valve 38
A temperature detector 38a is provided at the refrigerant outlet of the cold heat utilization facility 14 in order to control the opening degree of the cooling water.

In the upper chamber 28 of the CRE 4, a plurality of coiled heat transfer tubes 40 are wound around a cylinder 42. The coolant is stored in an annular gap formed between the body 24 and the cylinder 42. The lower chamber 30 of the fuselage contains a finned U
A plurality of letter-shaped heat transfer tubes 44 are arranged. Each U-shaped heat transfer tube 4
Both ends of the inlet liquid header 4 provided on the partition plate 26
6 and a gas header 48 respectively. LNG is supplied to the inlet liquid header 46, and NG is extracted from the gas header 48 via the plurality of coiled heat transfer tubes 40.

If a line 50 indicated by a broken line is provided,
Even when heat cannot be supplied from a business such as a refrigerated warehouse as the cold heat utilization facility 14, LNG can be stably vaporized to room temperature. That is, when the on-off valve 52 is opened, the low-temperature refrigerant that has exchanged heat in the U-shaped heat transfer tube 44 and the lower chamber 30 can be supplied from the ring tube 8D to the heat source such as the air conditioner 16 via the line 50. become. The refrigerant, which has been heated to a high temperature by the heat from the air conditioner 16, returns to the upper chamber 28 from the ring tube 8A, and flows to the lower chamber 30 through a passage provided in the partition plate 26.

As shown in FIG. 2, the CRE 4 has a cylindrical body 24. The body 24 has a cylindrical side wall 54 extending vertically and a hemispherical bottom wall provided at the lower end of the side wall 54. 56. The inside of the body 24 is partitioned into an upper chamber 28 and a lower chamber 30 by a circular partition plate 26. In this embodiment, the inside diameter of the body 24 is set to about 900 mm. A gap of about 2 to 3 mm is provided between the outer peripheral surface of the partition plate 26 and the inner peripheral surface of the side wall 54 of the body 24, and this gap serves as a refrigerant passage.

In the body 24, a plurality of U-shaped heat transfer tubes 4
4 are provided. As shown in FIG. 3, the U-shaped heat transfer tube 44 includes a first linear portion 58 extending vertically in the right side of FIGS. 1 and 2 and a second linear portion 58 extending vertically in the left side of FIGS. And the lower ends of the first and second linear portions 58 and 60 are connected by a curved portion 62 that is curved in an arc along the bottom wall 56. 1 and 2, the U-shaped heat transfer tubes 44 are spaced apart in a direction perpendicular to the sheet of FIG.
Approximately 20 are arranged at a pitch interval of about mm,
LNG cooled to about 160 ° C. is supplied to these U-shaped heat transfer tubes 44 via an inlet liquid header 46 as shown by an arrow 64. The LNG thus supplied is vaporized as described later while flowing through the U-shaped heat transfer tube 44, and the vaporized NG passes from the gas header 48 through the coiled heat transfer tube 40 as shown by an arrow 66. Is transmitted from CRE4.

In the lower chamber 30 of the body 24, a plurality of baffle plates 68 are arranged at intervals in the vertical direction. As shown in FIG. 3, the baffle plate 68 has a notch 70 cut in a chord on one side. Such a baffle 68
Are arranged so that the positions of the notches 70 are alternately arranged between the vertically adjacent baffle plates 68. That is, in the topmost and odd-numbered baffles 68 from the top, the notches 70 are arranged so as to be located on the right side in FIGS. Are arranged such that the notch 70 is located on the left side in FIGS. By arranging the baffle plate 68 in this manner, the flow path of the refrigerant in the lower chamber 30 is bent by the baffle plate 68 and extends in the left-right direction in FIGS. A gap of about 2 to 3 mm is formed between the outer peripheral surface of the baffle plate 68 and the inner peripheral surface of the side wall 54 of the body 24, similarly to the partition plate 26, and the flow of the refrigerant through this gap is allowed. .

As described above, alcoholic water is used as the refrigerant. The alcoholic water to be cooled consists, for example, of less than 60% by weight of ethanol and the balance water, the solidification temperature of which is about -43.5 ° C. Note that CR
E4 fuselage 24, partition plate 26, coiled heat transfer tube 40, U
The heat transfer tube 44, the inlet liquid header 46, the gas header 48, and the baffle plate 68 can be formed of stainless steel having excellent low-temperature resistance, for example, SUS304.

As shown in FIG. 2, the CRE4 of this embodiment is
Further, the upper end of the body 24 is opened, and the lid member 72 is detachably attached to this opening. Lid member 7
2 has an inlet connecting pipe 7 extending therethrough and extending vertically.
4 and an outlet connection pipe 76 are provided. The inlet header 46 is connected to the lower end of the inlet connection pipe 74, and the upper end of the first straight portion 58 of each U-shaped heat transfer tube 44 is connected to the inlet header 46 at intervals. An outlet header 78 is connected to the lower end of the outlet connection pipe 76, and the upper ends of the coiled heat transfer tubes 40 are connected to the outlet header 78 at intervals. The lower end of each coiled heat transfer tube 40 is connected to a gas header 48 at an interval.
The upper ends of the second straight portions 60 of the U-shaped heat transfer tubes 44 are connected at intervals. With this configuration, the LNG supplied from the inlet connection pipe 74 as shown by the arrow 64
Is supplied to each U-shaped heat transfer tube 44 via the inlet header 46, and heat is exchanged with the alcoholic water in the lower chamber 30 while being sent through each U-shaped heat transfer tube 44. The vaporized NG is transferred to the coiled heat transfer tube 4 via the gas header 48.
The heat is exchanged with the alcoholic water in the upper chamber 28 and sent out from the outlet connection pipe 76 through the outlet header 78 as shown by an arrow 66.

Referring to FIG. 4 to FIG. 6, the first and second straight portions 58 and 60 of the U-shaped heat transfer tube 44 include:
An inner fin member 80 and an outer fin member 82 are arranged between the adjacent partition plate 26 and baffle plate 68. As shown mainly in FIG. 4, the baffle plate 68 includes
In FIG. 3, a plurality of pairs of through-holes 84 are provided at intervals in a direction perpendicular to the paper surface in correspondence with the number of each U-shaped heat transfer tube 44 (only five pairs are shown in FIG. ) Is provided. The through holes 84 of the baffle plate 68 are formed substantially at the same position. Therefore, when the baffle plate 68 is arranged in the vertical direction, the through holes 84 are arranged substantially in the vertical direction. Each of the through holes 84 is formed in the baffle plate 68.
Accordingly, a notch slit 86 extending in a direction substantially perpendicular to the direction in which the U-shaped heat transfer tubes 44 are provided is formed. The slit 86 is formed from the outside of the baffle 68
It extends straight through the corresponding through hole 84. The partition plate 26 also has a through hole similar to the baffle plate 68.

As shown in FIGS. 2, 4, 5 and 6, the first and second straight portions 5 of each U-shaped heat transfer tube 44 are provided.
8, 60 are mounted through a pair of through holes 84 of the baffle plate 68, and the same applies to the partition plate 26. In particular, as shown in FIG. 5, the inner diameter of the through hole 84 of the baffle plate 68 is set to, for example, about 20 mm, while the outer diameter of the first and second straight portions 58, 60 of each U-shaped heat transfer tube 44 is For example, it is set to about 19 mm. The gap d2 between the baffle plate 68 and the first and second linear portions 58, 60 of each U-shaped heat transfer tube 44 is, for example, about 0.5 mm over the entire circumference of the linear portions 58, 60. With this configuration, the alcohol water in the lower chamber 30 can flow through the gap d2 when ice does not freeze as described later.

In this embodiment, the inner fin member 80 is provided so as to penetrate an inner portion 86a (a portion extending inward from the through hole 84) of the cut slit 86 of the baffle plate 68. The inner fin member 80 is formed of, for example, an elongated plate-like member, and as shown in FIG.
4 extends in the axial direction along the straight portions 58, 60, one side of which contacts the bottom surface of the inner portion 86 a of the cut slit 86, and the other side contacts the straight portions 58, 60 of the U-shaped heat transfer tube 44. It is provided as follows. The inner fin members 80 are preferably provided so as to penetrate them from the uppermost to the lowermost baffles 68 in the body 24, and by providing such, the desired heat transfer effect and cold storage effect to be described later are achieved. Is done. In addition, such an inner fin member 8
For example, 0 can be formed so that its width d3 (FIG. 5) is about 50 mm and its axial length is about 6,000 mm.

An outer fin member 82 is provided so as to penetrate an outer portion 86b (a portion extending outward from the through hole 84) of the cut slit 86 of the baffle plate 68. The outer fin member 82 is formed of, for example, an elongated plate-like member, and as shown in FIG.
8, 60 along its axis, one side of which
The heat transfer tube 44 is provided so as to be in contact with the linear portions 58 and 60, and the other side faces the opening of the slit 86. The outer fin members 82 are also preferably provided so as to penetrate them from the uppermost to the lowermost baffles 68 in the body 24, and by providing such, the desired heat transfer effect and cool storage effect to be described later are achieved. Is done. The outer fin member 82 has, for example, a width d4 (FIG. 5) of 50 to 1.
Approximately 00 mm and its axial length is 6,000
mm, and can be formed of an aluminum alloy together with the inner fin member 80.

Next, the operation of the above-described CRE 4 will be described as follows. Referring again mainly to FIG. 2, LNG is connected to the inlet connection pipe 7 as indicated by arrow 64.
4 and the inlet header 46, the heat is supplied to each of the U-shaped heat transfer tubes 44 in the lower chamber 30, flows down the first straight portion 58 from above, passes through the curved portion 62, and passes through the second straight line 58. The part 60 flows upward from below. Thus, LNG
Flows, heat exchange is performed between LNG and alcoholic water as a refrigerant, and LNG is vaporized to NG
And gather at the gas header 48. From the gas header 48, in the upper chamber 28, NG that flows upward from below in the coiled heat transfer tube 40 and exchanges heat with the alcoholic water and is heated to normal temperature is heated to the room temperature. Exit 76
Out in the direction indicated by the arrow 66.

Referring to FIG. 1, the lower chamber 30 of the body 24
Alcohol water inside, from top to bottom, actually Figure 2
Heat is exchanged with the LNG while flowing through the flow path formed by bending the baffle plate 68 shown in FIG. 6, and thereby cooled as required, and the cooled alcohol water is removed from the lower chamber. The water is fed from the vicinity of the lower end of 30 to the cold heat utilization facility 14 via the ring tube 8D. Alcohol water pumped by the low-temperature refrigerant circulation pump 12 is supplied to the vicinity of the upper end of the lower chamber 30 via the ring pipe 8C. The refrigerant circulation pump 12 has a stratified cold storage heat storage tank
Alcohol water at −15 ° C. and alcohol water at −40 to −30 ° C. are supplied with their flow rates adjusted via the nozzle 8F and the low-temperature system flow control valve 32 and the nozzle 8H and the low-temperature system temperature control valve 36, respectively. . The alcohol water heated by the cold heat utilization facility 14 returns to the stratified cold storage heat storage tank 6 from the nozzle 8G. When the load on the cold heat utilization equipment 14 is small, the low-temperature alcohol water extracted from the ring pipe 8D is supplied to the stratified cold storage heat storage tank 6 via the low-temperature system pressure control valve 34.
The nozzle 8I near the lower end returns to the stratified cold storage heat storage tank 6.

In this embodiment, the temperature of the alcohol water flowing through the upper chamber 28 is around room temperature, for example, -15 to -5.
Set to ° C. The alcohol water thus cooled can be used for cooling, for example, the air conditioner 16 from the ring pipe 8B near the lower end of the upper room 28. Alcohol water of about 10 ° C. is returned from the air conditioner 16 to the vicinity of the upper end of the upper room 28 via the ring pipe 8A.
With this setting, the temperature of the natural gas discharged from the outlet connection pipe 76 can be set to a normal temperature of 5 ° C. or higher, and therefore, the natural gas discharged from the natural gas can be used as it is as city gas for household use. it can.

The CRE 4 of this embodiment has the following features. First, since the alcoholic water in the lower chamber 30 is cooled to −35 ° C. or lower, the linear portions 58 and 60 of the U-shaped heat transfer tube 44 are iced with the alcoholic water and interfere with the linear portions 58 and 60. The gap between the plate 68 is clogged with the iced ice, so that the linear portions 58 and 60 and the baffle plate 68 conduct heat through the ice. Therefore, the baffle plate 68 acts as a heat transfer fin integrated with the linear portions 58 and 60 of the U-shaped heat transfer tube 44 by the iced alcohol water. Thus, since the baffle plate 68 has a heat transfer function, heat exchange with alcoholic water is performed efficiently. In addition, since alcohol water comes to ice on a part of the surface of the baffle plate 68, the baffle plate 68 also has a cold storage function, and can store cold heat.

Second, the straight portions 58 of the U-shaped heat transfer tube 44,
The inner fin member 80 and the outer fin member 82 are provided so as to be in contact with the inner fin member 60.
Acts as heat transfer fins integral with 8,60. As described above, since the inner fin member 80 and the outer fin member 82 have a heat transfer function, heat exchange with alcoholic water is performed efficiently. In addition, alcohol water comes to ice on the inner fin member 80 and the outer fin member 82 along the surface. Therefore, since ice adheres to the inner fin member 80 and the outer fin member 82 in the lower chamber 30, it can be expected to store cold heat, and the volume of the cold storage tank conventionally required in such a cold heat system is reduced. Can be reduced.

In the CRE 4 described above, the U-shaped heat transfer tube 44
The inner fin member 80 and the outer fin member 82 are provided on each of the straight portions 58 and 60. However, when a sufficient heat transfer effect and a cool storage effect are achieved, one of the inner fin member 80 and the outer fin member 82 is used. May be omitted, and the inner fin member 80 and the outer fin member 82 may be provided on one of the straight portions 58 and 60 instead of being provided on both of them. The U-shaped heat transfer tubes 44 and the baffle plates 68 can be provided in an appropriate number in consideration of the performance of the CRE 4.

FIG. 7 shows a configuration in which one or more CRE4s are used in the stratified cold storage tank 6 of the cooling system shown in FIG. 1 according to the vaporization capacity of LNG. FIG.
In (a), three CRs are stored in the stratified cold storage heat storage tank 6.
In the case where E4 is stored, (b) shows a case where four CRE4s are used. The inlet connection pipe 74 and the outlet connection pipe 76 of each CRE 4 are connected to an inlet ring 88 and an outlet ring 90, respectively. Even when there are five or more CREs 4, they can be similarly arranged on the circumference and combined. Since a very large CRE4 has a problem in strength and is not efficient, it is preferable to use a plurality of CRE4s rather than one large CRE4 even if the LNG to be vaporized has a large capacity. . However, with six or more units, it is difficult to evenly distribute the refrigerant and LNG.

As described above, when the present invention is applied, LNG cold heat can be cascadedly used for refrigerated warehouses, frozen foods, air conditioning, etc., and a compact and economical LNG having a cold storage heat function can be used. A refrigeration system including the vaporizer CRE4 can be obtained. The refrigeration system to which the present invention is applied includes a stratified refrigeration storage tank 6 using less than 60 wt% alcoholic water as a refrigeration agent, and a vertical U-tube LNG
This is a compact and low-cost system that integrates a vaporizer and vaporizes and raises LNG to room temperature. The stratified regenerative heat storage tank 6 has three different regenerative temperature layers of 10 ° C., −20 ° C., and −35 ° C., and always stores a heat source capable of evaporating to 0 ° C. or more even when the load of LNG fluctuates. Can be.

CRE4, a vertical U-tube LNG vaporizer
Is a type in which LNG flows into the U-shaped heat transfer tube 44 and alcohol water flows outside the tube. Even when the alcohol water lands on the U-shaped heat transfer tube 44, the flow path resistance is small and the cold heat is stably used. A new type of LN that can supply low-temperature refrigerants to businesses
G vaporizer. In order to improve the heat transfer performance at the time of icing, the inside of the body 24 is divided by a middle plate 68 to increase the passing speed of the alcoholic water, and the U-shaped heat transfer tube 44 made of stainless steel has a high heat conductivity such as an aluminum material. The heat transfer area outside the tube was increased along the fins 80 and 82.

In order to cope with large-volume LNG vaporization while utilizing the concept of enhancing the heat transfer performance,
A plurality of CREs 4 were collectively arranged on a concentric circle and stored in the stratified cold storage tank 6.

When the present invention is applied, the following features are obtained.

A) Even if the heat load of the cold heat utilization equipment (refrigerated warehouse or the like) is lost, the LNG is stably vaporized to room temperature by operating the high-temperature circulation line of the heat source such as the outside air or the gas engine. be able to. In the conventional air temperature system that heats NG at the atmospheric temperature, if the outside air temperature drops or the performance decreases due to icing, it is necessary to operate a separately installed hot water vaporizer. if,
LNG cold energy can be used throughout the year, and LNG
The vaporization system of G can be simplified.

B) 100% effective use of LNG refrigeration can be achieved by a stratified refrigeration storage tank integrated with the CRE even with respect to changes in LNG vaporization flow rate and load fluctuations of refrigeration equipment. In addition, because of the integrated structure, only a small installation space is required, and it is not necessary to keep the CRE cool, so that construction costs can be reduced.

C) Since less than 60% by weight of alcoholic water, which is not applicable to dangerous substances, is used as a refrigerant and stored in a stratified type cold storage heat storage tank at atmospheric pressure, it is easier to maintain and manage than conventional Freon refrigerants and ammonia refrigerants. .

Further, as an application of the present invention, the C
The RE may have a function of mixing and vaporizing LPG for adjusting the calorific value of the city gas. The amount of LPG liquid necessary for heat quantity adjustment is sprayed into the gas header of the U-shaped heat transfer tube, mixed with NG at about −40 ° C., and heated to room temperature by the coiled heat transfer tube. Thereby, the conventional LP
The G vaporization system can be simplified, and the heat source for raising the temperature can be effectively used as a cooling heat source for air conditioning or the like.

[0051]

As described above, according to the present invention, the natural gas vaporized in the chamber below the partition of the fuselage is heated to room temperature in the chamber above the fuselage, and the cold generated at that time is reduced. It can be used effectively. In the chamber below the partition plate, the refrigerant is cooled to a low temperature, and the cold heat can be effectively used in a low-temperature cold heat utilization facility such as a refrigerated warehouse or frozen food. The cold heat of the refrigerant near room temperature, which is cooled by heat exchange in the upper chamber, can be effectively used in, for example, air conditioning.

Further, according to the present invention, natural gas can be supplied at a stable temperature even if the heat load on the cold heat utilization side and the natural gas supply amount fluctuate.

Further, according to the present invention, since the liquefied natural gas vaporizer is integrated into the cold storage tank, the installation place is small. The refrigerant in the cold storage tank forms approximately three temperature stratifications in the vertical direction, and the adjusting means adjusts the interface position between the temperature stratifications of the refrigerant. The cold heat of the gas can be effectively used. Since the body of the liquefied natural gas vaporizer is stored in the refrigerant in the cold storage heat storage tank, a refrigeration system having a large liquefied natural gas vaporization capability can be configured compactly and at low cost.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing an overall configuration of a cooling and heating system according to the present invention.

FIG. 2 is a simplified cross-sectional view showing a schematic configuration of CRE4 in FIG.

FIG. 3 is a partially omitted perspective view showing a U-shaped heat transfer tube 44 and a baffle plate 68 in a room 30 below the CRE 4 in FIG. 2;

FIG. 4 is a perspective view showing a baffle plate 68 and a U-shaped heat transfer tube 44 of the CRE 4 of FIG.

FIG. 5 is a view showing a state in which U is inserted into a through hole 84 of the baffle plate 68 of the CRE 4 shown in FIG.
FIG. 4 is a cross-sectional view perpendicular to the axis of the tube showing a state in which the heat transfer tube 44 is inserted.

FIG. 6 is a cross-sectional view parallel to the axis of the tube showing a fin member attached to the U-shaped heat transfer tube 44 of the CRE 4 in FIG. 2;

FIG. 7 is a diagram showing a plurality of CRE4s in the stratified cold storage heat storage tank 6 of FIG.
It is the simplified top view and front view which show the structure at the time of storing.

[Explanation of symbols]

 Reference Signs List 4 CRE 6 Stratified cold storage heat storage tank 10, 12 Refrigerant circulation pump 14 Cooling heat utilization equipment 16 Air conditioning equipment 20 High temperature system flow control valve 22 High temperature system temperature control valve 24 Body 26 Partition plate 28 Upper room 30 Lower room 32 Low temperature system flow Control valve 34 Low temperature system pressure control valve 36 Low temperature system temperature control valve 40 Coiled heat transfer tube 42 Cylindrical body 44 U-shaped heat transfer tube 48 Gas header 68 Baffle plate 80 Inner fin member 82 Outer fin member 88 Inlet ring 90 Outlet ring

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hideyuki Sakamoto 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture Examiner, Osaka Gas Co., Ltd. Tetsuro Senju (56) References JP-A-9-318217 ( JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F28D 7/16 F17C 9/02 F25D 3/10 F28D 20/00

Claims (3)

(57) [Claims] 1. A body extending vertically and divided into upper and lower chambers by a partition plate, and a plurality of the fins are disposed in a chamber below the partition plate of the body, and a substantially U-shaped vertical fin is provided. A U-shaped heat transfer tube that is attached and to which liquefied natural gas is supplied; a header that is arranged near the partition plate and to which outlet sides of the plurality of U-shaped heat transfer tubes are connected; and a partition plate of the body A cylinder disposed in the upper chamber so as to form an annular gap with the body, and a plurality of coils housed in the gap between the cylinder and the body, and a plurality of coils disposed on the outer peripheral surface of the cylinder. And a coil-shaped heat transfer tube whose lower end is connected to the header. The chamber below the partition plate of the body exchanges heat with liquefied natural gas in the U-shaped heat transfer tube. A low-temperature refrigerant for vaporizing the liquefied natural gas is circulated, and the coiled transmission is provided in the annular gap in the chamber above the partition plate of the body. A liquefied natural gas vaporizer characterized by flowing a normal-temperature refrigerant for exchanging heat with natural gas in a heat pipe to raise the temperature of natural gas to room temperature. 2. The low-temperature refrigerant and the room-temperature refrigerant are the same refrigerant having different temperatures. The partition plate of the body is provided with a passage that allows the refrigerant to flow, and the demand for the cold heat of the room-temperature refrigerant is increased. 2. The liquefied natural gas vaporizer according to claim 1, further comprising a cold replenishing means for replenishing the refrigerant by using the cold heat of the low-temperature refrigerant when increasing. 3. A cold storage tank for storing one or more liquefied natural gas vaporizers according to claim 1 or 2, wherein the refrigerant stored therein forms approximately three temperature stratifications in the vertical direction. And adjusting means for adjusting the interface position of the temperature stratification of the refrigerant in the cold storage heat storage tank in accordance with a change in the vaporization flow rate of the liquefied natural gas and a change in the load utilizing cold from the refrigerant. A refrigeration system using a liquefied natural gas vaporizer.