WO2017104293A1

WO2017104293A1 - Intermediate-medium type vaporizer

Info

Publication number: WO2017104293A1
Application number: PCT/JP2016/082993
Authority: WO
Inventors: 和彦浅田; 正英岩崎
Original assignee: 株式会社神戸製鋼所
Priority date: 2015-12-18
Filing date: 2016-11-07
Publication date: 2017-06-22

Abstract

This intermediate-medium type vaporizer is provided with: an intermediate medium evaporation part that evaporates at least a portion of an intermediate medium through heat exchange performed between a first heat source medium and the intermediate medium in a liquid form; a liquid gas vaporizing part that has a heat transfer tube through which a low-temperature liquid gas having a pressure of at least 6 MPaG is introduced, and vaporizes the low-temperature liquid gas in the heat transfer tube to cause a gas to flow out by condensing the intermediate medium evaporated by the intermediate medium evaporation part; and a heater that heats, by means of a second heat source medium, the gas discharged from the liquid gas vaporizing part. The first heat source medium is seawater or atmospheric air, the second heat source medium is steam or warm water, and the heater is provided with a microchannel heat exchanger.

Description

Intermediate medium vaporizer

The present invention relates to an intermediate medium type vaporizer.

Conventionally, as disclosed in Patent Document 1 below, as an apparatus for vaporizing a low temperature liquid such as LNG (Liquid Natural Gas), an intermediate medium type vaporizer that uses an intermediate medium in addition to a heat source fluid is known. As shown in FIG. 5, the intermediate medium vaporizer disclosed in Patent Document 1 includes an intermediate medium evaporator 81, an LNG evaporator 82, and a warmer 83.

The vaporizer is provided with an inlet chamber 85, a large number of heat transfer tubes 86, an intermediate chamber 87, a large number of heat transfer tubes 88, and an outlet chamber 89 in this order as a path through which seawater as a heat source fluid passes. . The heat transfer tube 86 is disposed in the heater 83, and the heat transfer tube 88 is disposed in the intermediate medium evaporator 81.

In the intermediate medium evaporator 81, an intermediate medium (for example, propane) M having a boiling point lower than the temperature of seawater is accommodated.

The LNG evaporator 82 includes an inlet chamber 91 and an outlet chamber 92, and a large number of heat transfer tubes 93 communicating with both the chambers 91 and 92. Each heat transfer tube 93 is substantially U-shaped and protrudes to the upper part in the intermediate medium evaporator 81. The outlet chamber 92 communicates with the warmer 83 via the NG conduit 94.

In such a vaporizer, seawater that is a heat source fluid passes through the inlet chamber 85, the heat transfer tube 86, the intermediate chamber 87, and the heat transfer tube 88 to the outlet chamber 89, but the seawater that passes through the heat transfer tube 88 passes through the intermediate medium evaporation. Heat exchange with the liquid intermediate medium M in the vessel 81 evaporates the intermediate medium M.

On the other hand, LNG to be vaporized is introduced into the heat transfer tube 93 from the inlet chamber 91. The heat exchange between the LNG in the heat transfer tube 93 and the evaporation intermediate medium in the intermediate medium evaporator 81 causes the intermediate medium M to condense, and the LNG evaporates in the heat transfer tube 93 by receiving the heat of condensation. (Natural Gas). This NG is introduced into the heater 83 from the outlet chamber 92 through the NG conduit 94, further heated by heat exchange with seawater flowing through the heat transfer pipe 86 in the heater 83, and then supplied to the use side. The

JP 2000-227200 A

In the intermediate medium type vaporizer disclosed in Patent Document 1, the warmer 83 has a large number of heat transfer tubes 86. For this reason, there is a limit in reducing the size of the heater 83, and there is inevitably a limit in reducing the size of the intermediate medium type vaporizer itself. In particular, when high-pressure LNG is introduced into the intermediate medium type vaporizer, the pressure in the heater 83 also increases, so that the heat transfer tube 86 and its associated tube plate and shell are also required to have pressure resistance. In other words, downsizing becomes increasingly difficult in order to achieve pressure resistance performance commensurate with it.

Therefore, the present invention has been made in view of the above prior art, and an object of the present invention is to provide an intermediate medium type vaporizer that can be miniaturized.

In order to achieve the above object, an intermediate medium vaporizer provided as one aspect of the present invention evaporates at least a part of the intermediate medium by heat exchange between the first heat source medium and the liquid intermediate medium. A low temperature liquefied gas in the heat transfer tube by condensing the intermediate medium evaporated in the intermediate medium evaporation unit, and having a heat transfer tube into which a low temperature liquefied gas having a pressure of 6 MPaG or more is introduced. It is an intermediate-medium vaporizer provided with the liquefied gas vaporization part which vaporizes and flows out gas, and the warmer which heats the gas which flowed out from the liquefied gas vaporization part with the 2nd heat source medium. The first heat source medium is seawater or the atmosphere, the second heat source medium is steam or hot water, and the warmer is configured by a microchannel heat exchanger.

It is a figure which shows roughly the structure of the intermediate | middle medium type vaporizer | carburetor which concerns on 1st Embodiment. It is a figure which shows schematically the structure of the warmer provided in the said intermediate | middle medium type vaporizer in the state which fractured | ruptured partially. It is a figure which expands and shows the layered product provided in the warmer partially. It is a figure which shows roughly the structure of the intermediate-medium type vaporizer | carburetor which concerns on 2nd Embodiment. It is a figure which shows roughly the structure of the conventional intermediate | middle medium type vaporizer | carburetor.

Hereinafter, embodiments will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, an intermediate medium type vaporizer (hereinafter simply referred to as a vaporizer) 10 according to the first embodiment converts the heat of seawater, which is a first heat source medium, into a low-temperature liquefied gas via an intermediate medium M. This is a device that transmits to liquefied natural gas (LNG) and obtains gas by vaporizing LNG. The vaporizer 10 may be configured as a device that vaporizes or heats a low-temperature liquefied gas other than LNG, such as liquefied petroleum gas (LPG) or liquid nitrogen (LiN Nitrogen, LN ² ).

The vaporizer 10 includes an intermediate medium evaporator E1 that is an intermediate medium evaporator, an LNG evaporator E2 that is a liquefied gas vaporizer, and a heater E3. The intermediate medium evaporator E1 and the LNG evaporator E2 are provided in one hollow casing 11.

The casing 11 has a shape that is long in the horizontal direction, and a lower part thereof is configured as a casing part (first casing part) of the intermediate medium evaporator E1, and an upper part is formed as a casing part (second casing part) of the LNG evaporator E2. It is configured.

The inlet chamber (water chamber) 14 is adjacent to one of the pair of side walls constituting the first casing portion, and the outlet chamber 18 is adjacent to the other. A number of heat transfer tubes 20 are provided in the intermediate medium evaporator E1. The heat transfer tube 20 is disposed in the lower part of the space in the casing 11. The heat transfer tube 20 includes a first side wall 11 a that functions as a partition wall with the inlet chamber 14 and a second side wall that functions as a partition wall with the outlet chamber 18 among a pair of side walls facing each other constituting the first casing portion. 11b. The heat transfer tube 20 has a shape extending linearly in one direction, but is not limited to this shape.

The inlet chamber 14 is connected to an inlet pipe 22 provided with a pump or the like (not shown), and seawater pumped from the sea is introduced into the inlet chamber 14 through the inlet pipe 22. That is, seawater before being introduced into the entrance chamber 14 is not used to heat NG (Natural Gas).

A discharge pipe 24 for discharging seawater is connected to the outlet chamber 18. Seawater in the outlet chamber 18 is discharged to the outside through the discharge pipe 24.

In the casing 11, an intermediate medium (for example, propane) M having a boiling point lower than the temperature of seawater is accommodated. The intermediate medium M is accommodated so that the liquid level is located above all the heat transfer tubes (heat transfer tubes through which seawater flows) 20.

Above the outlet chamber 18, an LNG inlet chamber 32 and an outlet chamber 34 for leading out NG are provided. The entrance chamber 32 and the exit chamber 34 are adjacent to the outside on the upper side of the second side wall 11b. The outlet chamber 34 is formed adjacent to the upper side of the inlet chamber 32. A supply pipe 36 for introducing LNG is connected to the inlet chamber 32. A lead-out pipe 38 for leading out NG is connected to the outlet chamber 34. LNG having a pressure of 6 MPaG (gauge pressure of 6 MPa) or more is introduced into the inlet chamber 32.

The LNG evaporator E2 includes the inlet chamber 32, the outlet chamber 34, and a large number of heat transfer tubes 40 that connect the inlet chamber 32 and the outlet chamber 34. Each heat transfer tube 40 is substantially U-shaped, and has a first end connected to the inlet chamber 32 and a second end connected to the outlet chamber 34. The heat transfer tube 40 is disposed above the heat transfer tube 20 in the casing 11, that is, above the liquid level of the intermediate medium M.

The heater E3 is connected to the outlet pipe 38. NG is supplied to the heater E3 through the outlet tube 38, heated in the heater E3, and then supplied to the user side.

The warmer E3 is configured by a microchannel heat exchanger including a laminated body having a structure in which a large number of

metal plates

43 and 44 having excellent heat transfer characteristics shown in FIG. 3 are laminated. Specifically, as shown in FIGS. 2 and 3, the microchannel heat exchanger has a structure in which a laminate of

metal plates

43, 44 is sandwiched between

end plates

45, 45. The first metal plate 43 in which a large number of flow paths (first flow paths) 43a through which NG flows are recessed, and the large number of flow paths (second flow paths) 44a through which steam as a second heat source medium flows are recessed. The provided second metal plates 44 are alternately laminated. And heat exchange is performed between NG which flows through each 1st channel 43a, and steam which flows in each 2nd channel 44a, and NG is heated. The flow paths formed in these

metal plates

43 and 44 have a flow path width of 0.2 mm to 3 mm, for example. Note that hot water may be used as the second heat source medium instead of steam.

NG flows in each first flow path 43a, and steam such as water vapor as a second heat source medium flows in each second flow path 44a. In addition, the 2nd heat source medium should just be a heat source medium different from a 1st heat source medium (this embodiment seawater), for example, may be warm water.

A first inflow header 47 and a first outflow header 48 communicate with each first flow path 43a, and a second inflow header 49 and a second outflow header 50 are connected to each second flow path 44a. Are communicating. The NG supplied through the outlet pipe 38 is distributed to the first flow paths 43a through the first inflow headers 47, and the NG that has flowed through the first flow paths 43a gathers at the first outflow header 48 to be heated by the heater E3. Is derived from A steam supply pipe 51 is connected to the second inflow header 49. The steam supplied through the supply pipe 51 is distributed to each second flow path 44a through the second inflow header 49, and the steam that has flowed through each second flow path 44a gathers at the second outflow header 50 and is heated. Derived from the device E3.

Here, the operation of the vaporizer 10 according to the first embodiment will be described.

The liquid intermediate medium M stored in the lower part of the casing 11 is heated and evaporated by the seawater flowing into the heat transfer tubes 20 through the inlet chamber 14. That is, in the heating medium evaporating unit E1, the intermediate medium M is heated by the first heat source medium and evaporated. The evaporated intermediate medium M heats the heat transfer tube 40 located at the upper part in the casing 11. The LNG flowing from the supply pipe 36 into the heat transfer pipe 40 through the inlet chamber 32 and flowing through the heat transfer pipe 40 is heated by the heat transfer pipe 40 and evaporated to become NG. Seawater flows out of the heat transfer pipe 20 and is discharged to the outside through the outlet chamber 18 and the discharge pipe 24.

NG flows through the outlet pipe 38 via the outlet chamber 34 and is introduced into the heater E3. In the warmer E <b> 3, NG is diverted to the first flow paths 43 a through the first inflow header 47. The NG flowing through each first flow path 43a is heated by the steam flowing through each second flow path 44a, led out from the heater E3 through the first outflow header 48, and supplied to the use side.

As described above, in the present embodiment, since the warmer E3 is configured by a microchannel heat exchanger, the warmer is heated compared to the case where the warmer is configured by a shell and tube type heat exchanger. The size of the device E3 can be reduced.

Also, the vaporizer 10 itself can be downsized. In particular, LNG having a pressure of 6 MPaG (gauge pressure of 6 MPa) or more is introduced into the LNG evaporator E2. Even in the case of vaporizing such high-pressure LNG, since the heater E3 is composed of a microchannel heat exchanger, the heater is similar to the conventional intermediate medium vaporizer shown in FIG. There is no need to take measures such as increasing the thickness of the heat transfer tubes, tube sheets and shells of E3 to increase pressure resistance.

Therefore, it is possible to prevent the heater E3 from increasing in size while being configured to vaporize the high-pressure LNG. Further, as the heater E3 can be reduced in size, the heater E3 can be reduced in weight.

Further, the heater E3 is composed of a microchannel heat exchanger, and does not have an outer shell and a can plate as in the heater E3 of the intermediate medium type vaporizer in FIG. Since there is no structure that can withstand the high pressure in the compressing direction, even when a high-pressure gas is introduced into the warmer E3, the warmer E3 is not enlarged. In addition, in the structure of FIG. 5, in addition to the equipment becoming large and heavy, it is difficult to achieve a desired NG outlet temperature in the seawater low temperature period.

Moreover, in this embodiment, since steam is used as the second heat source medium, the heating performance of the gas in the heater E3 can be increased as compared with the case where seawater or air is used as the second heat source medium. it can. In a cold region, it is possible to obtain a gas having a temperature required from the use side.

Moreover, in this embodiment, there is an effect of reducing operating costs. This point will be specifically described below. The operating cost required for the configuration of the present embodiment is A, and the operating cost required for an all-steam heat source type vaporizer in which steam is also used as the first heat source medium is B. Make a comparison.

Of the total heat of vaporization (100%) in the vaporizer, the heat load distribution in the intermediate medium evaporator E1 and the warmer E3 is generally about 80% and about 20%, respectively. In this embodiment, 80% of the heat load is covered with inexpensive natural energy (seawater), and the remaining 20% is covered with expensive steam. On the other hand, in the all steam heat source type vaporizer, 100% of the heat load is covered by expensive steam (fuel thermal efficiency of about 90%).

The required basic unit of pump power (electric power) is about 4 kWh / t-LNG. Therefore, if the unit price of electric power is 10 ¥ / KWh, 40 yen is required to vaporize 40 ¥ / t-LNG, that is, LNG-1 ton. . On the other hand, since the basic unit of steam (fuel cost) is about 1.5% (when the thermal efficiency is 90%) on the basis of the fuel consumption, it is 15Kg / t-LNG. If the fuel gas unit price including 40,000 yen / t is 600 yen / t-LNG, that is, 600 yen is required to vaporize LNG-1ton.

In the vaporizer 10 according to the present embodiment, since the heat load is distributed between the intermediate medium evaporator E1: 80% and the warmer E3: 20%, the operating cost A is 40 × 0.8 + 600 × 0.2 = 152. ¥ / t-LNG. On the other hand, the operating cost B in the all steam heat source type vaporizer is 600% / t-LNG because it becomes a 100% steam heat source. Therefore, the operating cost is clearly A << B.

In addition, when viewed throughout the year, in the vaporizer 10 according to the present embodiment, in summer, the heat load on the intermediate medium evaporator E1 increases due to the rise in seawater temperature, and the heat load on the heater E3 decreases. As a result, the operating cost A is reduced. On the other hand, in the all-steam heat source type vaporizer, even if the heat load in the intermediate medium evaporator E1 increases, the operating cost B is not reduced.

Further, when partial load operation is unavoidable in operation, the vaporizer 10 of the present embodiment has a characteristic that the heat load in the intermediate medium evaporator E1 is large and the heat load in the heater E3 is small. Therefore, the operating cost A may be reduced beyond the partial load factor.

On the other hand, in the all-steam heat source type heater, the operating cost B does not decrease beyond this while maintaining the partial load factor. Since seawater temperature change and partial load operation are unavoidable, in the actual operation over the whole year, the above-mentioned synergistic effect will further increase the difference in the operation cost over the whole year to A << B.

(Second Embodiment)
FIG. 4 schematically shows the configuration of the vaporizer 10 according to the second embodiment. As shown in FIG. 4, in the second embodiment, unlike the first embodiment, the atmosphere is used as the first heat source medium. Here, only configurations and effects different from those of the first embodiment will be described.

In the first embodiment, the intermediate medium evaporator E1 and the LNG evaporator E2 are provided in the common casing 11, but in the second embodiment, the intermediate medium evaporator E1 and the LNG evaporator E2 are provided. And are configured separately.

The LNG evaporator E2 includes a housing 55 in which the intermediate medium M is enclosed, and a heat transfer tube 40 that is disposed in the housing 55 and vaporizes LNG. The housing 55 is provided with an inlet chamber 32 into which LNG is introduced and an outlet chamber 34 through which NG flows out. A liquid reservoir 55 a for storing the intermediate medium M is provided at the lower portion of the housing 55.

A circulation path 57 for the intermediate medium M is connected to the housing 55. One end of the circulation path 57 is connected to the lower surface of the liquid reservoir 55 a in the housing 55 and extends outside the housing 55. The other end of the circulation path 57 is connected to the upper surface of the housing 55. The circulation path 57 is provided with a pump 58. When the pump 58 is driven, the intermediate medium M stored in the liquid reservoir 55 a flows through the circulation path 57.

The heat transfer tube 20 of the intermediate medium evaporator E1 is connected to the intermediate portion of the circulation path 57. Therefore, the circulation path 57 includes a liquid pipe 57a through which the liquid intermediate medium M flows toward the heat transfer pipe 20, and a gas pipe 57b through which the gaseous intermediate medium M flows through the heat transfer pipe 20 and flows toward the LNG evaporation section E2. Including.

The intermediate medium evaporator E1 has a configuration in which the heat transfer tube 20 is disposed in a heat exchange chamber 60 into which air is introduced. A blower chamber 61 is provided above the heat exchange chamber 60, and the air flows into the heat exchange chamber 60 via the blower chamber 61 by driving the blower 62. In the present embodiment, the atmosphere flows from the top to the bottom, but the atmosphere may flow from the bottom to the top. Alternatively, the blower chamber 61 may be omitted, the blower 62 may be attached to the heat exchange chamber 60, and the atmosphere may be directly introduced into the heat exchange chamber 60. Alternatively, the air may flow from the heat exchange chamber 60 toward the blower chamber 61.

In the second embodiment, when the pump 58 is driven, the liquid intermediate medium M stored in the liquid reservoir 55a in the housing 55 flows through the liquid pipe 57a of the circulation path 57 and is transmitted to the intermediate medium evaporator E1. It is introduced into the heat pipe 20. In the heat transfer pipe 20, the intermediate medium M is heated and evaporated by the atmosphere and flows through the gas pipe 57 b of the circulation path 57. This gaseous intermediate medium M is introduced into the housing 55 of the LNG evaporation unit E2, and heats the heat transfer tube 40. Thereby, LNG in the heat transfer tube 40 is vaporized and becomes NG. NG is introduced into the heater E3 through the outlet tube 38, heated by steam, and then supplied to the user side.

[Outline of Embodiment]
From the first embodiment and the second embodiment, the intermediate medium type vaporizer provided as one aspect of the present invention will be outlined.

An intermediate medium vaporizer provided as one aspect of the present invention includes an intermediate medium evaporation unit that evaporates at least a part of the intermediate medium by heat exchange between the first heat source medium and the liquid intermediate medium, and 6 MPaG or more. A liquefaction having a heat transfer tube into which a low-temperature liquefied gas having a pressure of 5 is introduced and condensing the intermediate medium evaporated in the intermediate medium evaporation section, thereby vaporizing the low-temperature liquefied gas in the heat transfer tube A gas vaporizer; and a heater that heats the gas flowing out of the liquefied gas vaporizer with a second heat source medium. The first heat source medium is seawater or the atmosphere, the second heat source medium is steam or hot water, and the warmer is configured by a microchannel heat exchanger.

In this intermediate medium type vaporizer, since the heater is constituted by a micro-channel heat exchanger, the heater is downsized compared to the case where the heater is constituted by a shell and tube type heat exchanger. Can be achieved.

Moreover, the intermediate medium type vaporizer itself can be downsized. In particular, a low-temperature liquefied gas having a pressure of 6 MPaG (gauge pressure of 6 MPa) or more is introduced into the liquefied gas vaporization section. Even when vaporizing such high-pressure, low-temperature liquefied gas, since the heater is composed of a microchannel heat exchanger, the thickness of the heat transfer tubes, tube sheets, and shells can be increased to increase pressure resistance. There is no need to take measures to increase it.

Therefore, it is possible to prevent an increase in the size of the heater while being configured to vaporize the high-pressure low-temperature liquefied gas.

Also, as the heater can be reduced in size, the heater can be reduced in weight. In addition, since the second heat source medium is steam or hot water, the heating performance of the gas in the heater can be improved as compared with the case where seawater or air is used as the second heat source medium.

Also, in a cold region, it is possible to obtain gas at a temperature required from the user side.

Here, the microchannel heat exchanger is a heat exchanger provided with a laminate having a structure in which a large number of metal plates having excellent heat transfer characteristics are laminated. This laminated body has a configuration in which metal plates in which a flow path through which gas flows is recessed and metal plates in which a flow path through which the second heat source medium flows are alternately stacked. The channels formed in these metal plates have a channel width of 0.2 mm to 3 mm, for example. For this reason, even when a high-pressure gas is introduced into the warmer, it is not necessary to redesign the warmer for high pressure resistance, and the warmer is not enlarged.

As described above, the intermediate medium type vaporizer can be miniaturized.

Claims

An intermediate medium evaporating unit that evaporates at least a part of the intermediate medium by heat exchange between the first heat source medium and the liquid intermediate medium;
It has a heat transfer tube into which a low-temperature liquefied gas having a pressure of 6 MPaG or more is introduced, and condenses the intermediate medium evaporated in the intermediate medium evaporation section, thereby evaporating the low-temperature liquefied gas in the heat transfer tube and flowing out the gas A liquefied gas vaporizing section,
A heater that heats the gas flowing out of the liquefied gas vaporization section with a second heat source medium,
The first heat source medium is seawater or air, the second heat source medium is steam or hot water,
The warmer is constituted by a microchannel heat exchanger,
Intermediate medium vaporizer.