JP2008164177A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of miniaturizing the heat exchanger disposed on the way of a path for filling a hydrogen gas into a hydrogen automobile and the like, and having a large heat transfer area. <P>SOLUTION: This heat exchanger is provided with one curved refrigerant flow channel 5 formed by arranging a plurality of partitioning plates 4, 4,... in parallel with each other in a housing 1, one curved cooling pipe 6 is disposed in the refrigerant flow channel 5 through a gap, a cooling medium flows in the refrigerant flow channel 5, and a high pressure gas flows in the cooling pipe 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat exchanger that cools high-pressure gas, and more particularly to a heat exchanger that is used when a hydrogen vehicle is filled with hydrogen as a fuel.

As next-generation vehicles, development of hydrogen vehicles (fuel cell vehicles and hydrogen engine vehicles) using hydrogen gas as fuel is underway. Hydrogen automobiles are considered to be environmentally friendly automobiles that do not emit carbon dioxide, NOx, SOx, etc., and only discharge water.
A hydrogen vehicle travels to a supply base equipped with a fuel filling device (dispenser) for charging hydrogen gas as fuel, and replenishes hydrogen gas from the fuel filling device in the same manner as a normal gasoline vehicle when refueling. become.

In general, when compressed natural gas and other high-pressure gases (nitrogen gas, oxygen gas, etc.) are adiabatically expanded from a compressed state (for example, pressure of 35 MPa), the gas temperature is lowered by the Joule-Thompson effect.
However, unlike general gases, hydrogen gas is a gas that has the property of increasing temperature due to the Joule-Thompson effect. For this reason, the temperature of hydrogen gas tends to rise when passing through devices such as valves.
In addition, when filling a fuel tank with hydrogen gas, it is desired to fill the fuel tank in a short time, and the temperature rises due to adiabatic compression accompanying rapid filling of the fuel tank, so the gas temperature tends to rise. There is.

A fuel tank of a hydrogen automobile usually uses a fiber reinforced plastic (FRP) container for weight reduction. In the fuel tank made of FRP, the upper limit value of the use temperature is defined in consideration of durability, and the design value is generally about 85 ° C.
As described above, in the fuel tank made of FRP, since there is an upper limit on the use temperature, strict temperature control is required when filling with hydrogen gas.

  Filling hydrogen beyond the design temperature of the fuel tank is strictly prohibited. When full filling is detected by pressure monitoring and the filling is terminated, the tank pressure decreases when the fuel tank temperature drops after filling. . This means that the maximum filling amount (weight) that can be filled into the fuel tank is apparently reduced, which greatly affects the travel distance per filling of the hydrogen vehicle.

In particular, when the hydrogen filling pressure is 70 MPa, it is difficult to maintain a balance between rapid filling and temperature rise only by controlling the filling speed, and some kind of cooling device is required.
In addition, the higher the filling pressure, the greater the heat capacity due to the increased wall thickness of pipes, joints, and valves. Therefore, if cooling of the filling line is started after filling has started, the cooled hydrogen gas is also removed from the pipes and fittings. There is a problem that the initial purpose cannot be achieved for filling the fuel tank.

FIG. 6 shows a main part of a heat exchanger for cooling the high-pressure hydrogen gas used in the conventional high-pressure hydrogen gas filling. This heat exchanger is accommodated in a housing (not shown) and has a double piping structure.
In this heat exchanger, heat is exchanged by flowing hydrogen through the internal pipe 51 and a cooling medium such as brine between the internal pipe 51 and the external pipe 52. The heat exchanger is desired to be compact, but for this purpose, it is necessary to increase the heat transfer area for heat exchange, so that the internal pipe 51 is bent a plurality of times in the housing and reciprocated. .

Further, since a high-pressure hydrogen gas flows in the internal pipe 51, a thick stainless steel pipe or the like is used. However, since the standard length of the pipe material such as the thick stainless steel pipe is 2 m, the internal pipe 51 is used. In such a case, such a straight straight pipe is connected by a U-shaped bent pipe, or as shown in the figure, a straight straight pipe to be the internal pipe 51 is connected by elbows 54 and 54 and a short pipe 55. It has a reciprocating structure.
As a connection method, a method such as welding or screwing is used.
In the heat exchanger having such a structure, a seam is always generated. However, since high-pressure hydrogen gas flows in the internal pipe 51, there is no leakage from the seam due to the high-pressure gas safety law. Inspection is necessary.

Therefore, a single straight pipe without a seam is used as the internal pipe 51 of the heat exchange section, and an external pipe 52 is provided outside the internal pipe 51 to form an integrated double pipe. By integrating the heavy piping with the bent portion consisting only of the internal piping 51, the joint portion is opened to the atmosphere so that the inspection can be easily performed.
However, there is a problem that heat is not exchanged with the refrigerant at the joint, and the efficiency is low.

Further, it is necessary to continuously flow the cooling medium through the double pipe and the double pipe, and a branch portion 56 is provided in a part of each external pipe 52 and the branch portions 56 are connected to each other. Since the external pipe 52 has a larger diameter than the internal pipe 51, the radius of the bent portion is larger than the radius of the bent portion of the internal pipe 51. Further, for maintenance, the connection between the external pipe 52 and the external pipe 52 is joining by a flange 57. Accordingly, there is a problem that the interval between the external pipe 52 and the external pipe 52 becomes wide, and the heat exchanger becomes large.
JP 2004-116619 A

  The present invention has been made in consideration of the above circumstances, and provides a heat exchanger having a large heat transfer area while reducing the size of a heat exchanger provided in the middle of a path for filling hydrogen gas into a hydrogen vehicle or the like. For the purpose.

To solve this problem,
The invention according to claim 1 is a heat exchanger for cooling high-pressure gas,
A plurality of partition plates are provided in the casing in parallel to each other to form one bent refrigerant flow path, and one bent cooling pipe is provided in the refrigerant flow path via a gap,
In the heat exchanger, a cooling medium is allowed to flow through the refrigerant flow path, and the high-pressure gas is allowed to flow through the cooling pipe.

The invention according to claim 2 is the heat exchanger according to claim 1, wherein fins extending along a longitudinal direction of the pipe are provided.
The invention according to claim 3 is characterized in that the casing is composed of a main body and a lid portion that closes the main body, and the plurality of partition plates are provided on the main body or the lid portion. vessel.

In the heat exchanger of the present invention, almost the entire length of the pipe through which the high-pressure gas to be cooled flows is located in the refrigerant flow path, so that the heat transfer area can be increased, and as a result, the heat The exchanger can be made small.
Further, in the case where fins are provided in the pipe, the heat transfer area is further increased, and a further smaller heat exchanger can be obtained.

Furthermore, if the casing is composed of a main body and a lid portion and the main body or the lid portion is provided with the plurality of partition plates, the lid portion can be removed as necessary, and the internal high-pressure gas flows. The piping can be easily checked.
In addition, since the structure is simple, manufacturing is easy and can be provided at low cost.

1 and 2 show an example of the heat exchanger of the present invention.
In FIG. 1 and FIG. 2, the code | symbol 1 shows a housing | casing.
The housing 1 is in a sealed box shape made of a metal such as stainless steel, and includes a main body 2 and a lid 3.

  The main body 2 has a rectangular tray shape and has a wide opening, and the flat lid 3 covers the opening. The lid 3 is liquid-tightly attached to the main body 2 via a packing (not shown) with screws (not shown), and can be removed from the main body 2 as necessary.

In the main body 2, partition plates 4, 4. The partition plate 4 is provided in a state where it rises from the bottom of the main body 2 with an interval substantially parallel to each other along the longitudinal direction of the main body 2.
Of the two end portions in the longitudinal direction of the partition plate 4, one end portion is in direct contact with one side wall portion of the main body 2, and the other end portion extends to the other side wall portion of the main body 2. A gap is left without reaching.

And the joining form to the main body 2 side wall part of such a partition plate 4 is comprised so that it may join to the side wall part of the other side alternately in the partition plates 4 and 4 which adjoin each other.
In addition to welding, the plurality of partition plates 4, 4... Are joined to the main body 2 by cutting out a rectangular parallelepiped metal lump so that the main body 2 and the plurality of partition plates 4, 4. May be produced. In addition, you may make it adhere to the inner surface of the cover part 3 by welding etc., without integrating the some partition plates 4, 4, ... with the main body 2. FIG.
With the above configuration, a continuous and bent flow path having a ninety-nine fold shape is formed in the main body 2, and this flow path serves as the refrigerant flow path 5 through which the cooling medium flows. .

A single cooling pipe 6 is provided in the refrigerant flow path 5 to flow a high-pressure gas to be cooled. The cooling pipe 6 is provided with a gap away from each partition plate 4, the bottom of the main body 2 and the lid portion 3 so as to be positioned substantially at the center in the refrigerant flow path 5. It is a 99-fold bent shape that follows the shape of No. 5.
The cooling pipe 6 is supported in the refrigerant flow path 5 by a plurality of support bases 7 attached to the bottom of the main body 2. In FIG. 2, the support bases 7, 7,.

The cooling pipe 6 is formed by connecting a straight pipe and a U-shaped bent pipe, and this connection is performed by butt welding, insertion welding using a joint, or the like. However, the butt welding in which the diameter of the coolant does not increase is that the flow of the cooling medium in the refrigerant flow path 5 is not disturbed, the flow path is not narrowed, and the flow resistance of the cooling medium does not increase. Is preferable.
Moreover, it is good also as the cooling piping 6 which performs a bending process on a long straight pipe | tube, forms a curved part, and has the same shape.

  A refrigerant inlet 8 for introducing a cooling medium into the refrigerant flow path 5 and a refrigerant outlet 9 for extracting the cooling medium from the refrigerant flow path 5 are provided at positions corresponding to the start and end of the refrigerant flow path 5 in the lid 3. Is formed. Furthermore, an opening is formed at a position corresponding to the start end and the end of the cooling pipe 6 in the lid 3, and the start end 61 and the end 62 of the cooling pipe 6 are connected to the lid 3 via packing in the opening. On the other hand, it is inserted in a liquid-tight state and led out to the outside.

  In this heat exchanger, a cooling medium such as brine flows from the refrigerant inlet 8 into the refrigerant flow path 5 and is led out from the refrigerant outlet 9, and a gas such as high-pressure hydrogen to be cooled is supplied from the start end 61 of the cooling pipe 6. In order to increase the heat exchange efficiency, the flow direction of the cooling medium and the flow direction of the gas are counter-flowed to flow through the cooling pipe 6 and lead out from the end portion 62. , Each is supposed to flow.

  In such a heat exchanger, since almost the entire length of the cooling pipe 6 is present in the refrigerant flow path 5, the entire cooling pipe 6 contributes to heat exchange, and the heat transfer area is increased. For this reason, size reduction becomes possible. Furthermore, since the cover part 3 can be removed and the cooling pipe 6 in the housing 1 is exposed, the connection part can be easily observed and inspected.

In this example, a valve used when removing the cooling medium can be provided at the bottom of the housing 1, and a valve for exhausting the air flowing in at the beginning of operation can be arranged on the lid 3.
Further, one or more fins extending in the longitudinal direction of the cooling pipe 6 may be provided on the outer peripheral surface of the cooling pipe 6 to increase the heat transfer area.

  Moreover, in the heat exchanger of this example, the cover part 3 of the housing | casing 1 comprises the surface A of the housing | casing 1, However, Depending on the installation form at the time of use of a heat exchanger, the surface B of the housing | casing 1 Alternatively, the surface C can be constituted by the lid 3. In this case, the partition plate 4, 4... And the cooling pipe 6 are joined or supported and integrated with the side wall portion constituting the surface A of the housing 1, so that the cooling pipe can be removed by removing the lid 3. 6 is exposed and the cooling pipe 6 can be inspected.

  Further, a temperature sensor for measuring the temperature of the cooling medium is provided at the refrigerant inlet 8, and the flow rate of the gas flowing through the cooling pipe 6 is controlled based on the temperature of the cooling medium measured by the temperature sensor, whereby the gas is predetermined. Can be cooled to temperature.

3 and 4 show another example of the heat exchanger according to the present invention. In this example, the overall shape is a cylindrical shape.
In this example, the housing 11 has a columnar shape, the main body 12 constituting the housing 11 has a bottomed cylindrical shape, and the lid portion 13 that closes the circular opening of the main body 12 has a disk shape. It has become.
In FIG. 4, in order to explain the inside of the main body 12, it is drawn with the cylindrical portion of the main body 12 removed.

  Near the bottom of the main body 12, a refrigerant inlet 14 and a refrigerant outlet (hidden in FIG. 3) are provided on opposite sides of the outer peripheral surface. In the main body 12, a separating plate 16 is provided from the bottom of the main body 12 toward the opening so as to form a space A and a space B by substantially dividing the internal space of the main body 12 in the longitudinal direction. An opening 17 is formed in the vicinity of the opening of the main body 12 of the separation plate 16 so that the divided space A and space B are connected here.

  A plurality of partition plates 18, 18... Are attached between both side surfaces of the separation plate 16 and the inner peripheral wall of the main body 12 at intervals in parallel to each other. The planar shape of the partition plate 18 is a semicircular shape with a part cut away, and the cutout portions are arranged so as to be alternately positioned on the opposite side between the adjacent partition plates 18, 18. ing. As shown in the drawing, the partition plates 18, 18... Are similarly arranged in the space A and the space B, but the attachment positions in the longitudinal direction of the main body 12 may be slightly different.

  By providing such partition plates 18, 18..., The notched portions of the partition plates 18, 18... In which the cooling medium flowing in from the refrigerant inlet 14 is in one space A are zigzag-shaped toward the opening side. Flows through the opening 17 of the separation plate 16 and flows into the other space B, flows in a zigzag manner in the cut portions of the partition plates 18, 18... In the space B, and reaches the refrigerant outlet The refrigerant flow path is formed.

In the main body 12, one cooling pipe 19 is provided from the space A to the space B. The cooling pipe 19 is composed of a plurality of straight pipe sections 20, 20,... And a plurality of U-shaped pipe sections 21, 21 ..., and these straight pipe sections 20, 20,. -And are alternately connected to form one continuous tube.
The plurality of straight pipe portions 20, 20... Are provided through the plurality of partition plates 18, 18... And the lid portion 13 existing in the spaces A and B, and the plurality of U-shaped pipe portions 21. , 21... Are placed in the vicinity of the bottom of the main body 12, and the remaining U-tube portions 21, 21... Are placed above the lid portion 13. 22.

Further, the start end portion 23 and the end portion of the cooling pipe 19 are led out to the outside from the connection case 22, and the gas to be cooled is introduced from the start end portion 23 and can be led out from the end portion 24. .
Also in the heat exchanger of this example, a cooling medium such as brine flows from the refrigerant inlet 14 toward the refrigerant outlet, and a gas to be cooled such as hydrogen flows from the start end 23 to the end end 24 of the cooling pipe 19. Thus, this gas can be cooled.
In this example as well, since the cooling pipe 19 has almost the entire length in the refrigerant flow path, the heat transfer area increases, the heat exchange efficiency increases, and the size can be reduced. Moreover, since the cover part 13 can be removed and the cooling pipe 19 in the housing | casing 11 is exposed, the connection part can be observed and inspected easily.

Next, a method for cooling and supplying high-pressure hydrogen gas to a predetermined temperature using such a heat exchanger, such as a fuel tank of a hydrogen automobile, will be described.
FIG. 5 shows an example of an apparatus for carrying out such a method.
This apparatus is roughly composed of a hydrogen container 31... For storing high-pressure hydrogen gas at room temperature, the heat exchanger 10, and a storage tank 32 for storing a cooling medium such as brine as a cooling medium.

High-pressure hydrogen from the hydrogen container 31 flows through the high-pressure pipe 36 via the on-off valve 33, the flow meter 34, and the flow rate adjustment valve 35, and is supplied to the start end 61 of the cooling pipe of the main body of the heat exchanger 10. ing.
In the main body of the heat exchanger 10, the cooling medium from the storage tank 32 is supplied from the pipe 38 via the flow rate adjustment valve 37, and is sent from the refrigerant inlet 8 of the heat exchanger 10 to the refrigerant flow path. .

The cooling medium that has flowed through the refrigerant flow path of the heat exchanger 10 is led out from the refrigerant outlet 9 and sent to the refrigerator 42 through the pipe 41, where it is cooled and circulated to the storage tank 32. .
The hydrogen flowing through the cooling pipe of the heat exchanger 10 is cooled here, supplied from the terminal end 62 of the cooling pipe through the low-temperature pipe 39 through a valve, and supplied to a hydrogen automobile or the like, and filled in the fuel tank or the like. It is like that.

Further, the heat exchanger 10 is provided with a temperature sensor 40, and a temperature sensor 44 that measures the temperature of the hydrogen gas that flows through the low-temperature pipe 39 and a temperature sensor 45 that measures the temperature of the hydrogen gas that flows through the high-pressure pipe 26 are provided. .
Furthermore, a control unit 47 is provided for controlling the opening degree of the flow rate adjusting valves 35 and 37 based on the temperature signals from the temperature sensors 40, 44 and 45.

The normal-temperature high-pressure hydrogen gas in the hydrogen container 31 flows into the cooling pipe of the heat exchanger 10 through the high-pressure pipe 36, is cooled by heat exchange with the cooling medium in the refrigerant flow path, passes through the low-temperature pipe 39, Supplied to fuel tanks of hydrogen vehicles.
At this time, since the fuel tank of the hydrogen vehicle is required to be supplied at a predetermined temperature (for example, −40 ° C.), it is necessary to control the fuel tank to the predetermined temperature.

Specifically, the temperature of the cooling medium of the heat exchanger 10 by the temperature sensor 40 and the temperature of the hydrogen gas in the low temperature pipe 39 are measured by the temperature sensor 44. If the temperature is lower than the predetermined temperature, the flow rate adjusting valve 35 is measured. The opening of the flow rate adjustment valve 37 is controlled to be increased.
On the contrary, when the temperature is higher than the predetermined temperature, control is performed to reduce the opening degree of the flow rate adjustment valve 35 and increase the opening degree of the flow rate adjustment valve 37.
As a result, the high-pressure hydrogen gas can be maintained at a predetermined temperature and filled in a fuel tank such as a hydrogen automobile.
Note that the heat exchanger shown in FIGS. 3 and 4 can be similarly used for cooling the high-pressure hydrogen gas.

It is a schematic perspective view partly cut open which shows an example of the heat exchanger of this invention. It is a schematic plan view partly cut off showing an example of the heat exchanger of the present invention. It is a schematic perspective view which shows the other example of the heat exchanger of this invention. It is the schematic perspective view which abbreviate | omitted partially which shows the other example of the heat exchanger of this invention. It is a schematic block diagram which shows the apparatus for high pressure hydrogen gas filling using the heat exchanger of this invention. It is a perspective view which shows the principal part of the conventional heat exchanger for hydrogen gas.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Housing | casing, 2 ... Main body, 3 ... Cover part, 4 ... Partition plate, 5 ... Refrigerant flow path, 6 ... Cooling piping

Claims (3)

A heat exchanger for cooling high pressure gas,
A plurality of partition plates are provided in the casing in parallel to each other to form one bent refrigerant flow path, and one bent cooling pipe is provided in the refrigerant flow path via a gap,
A heat exchanger, wherein a cooling medium is allowed to flow through the refrigerant flow path, and the high-pressure gas is allowed to flow through the cooling pipe.   The heat exchanger according to claim 1, wherein fins extending along a longitudinal direction of the pipe are provided.   The heat exchanger according to claim 1, wherein the casing includes a main body and a lid portion that closes the main body, and the plurality of partition plates are provided on the main body or the lid portion.

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