JPH08189785A - Vaporizer for liquefied natural gas - Google Patents

Abstract

PURPOSE: To incorporate a function to control the heating value of NG, based on a simple, compact structure and addition of LPG, into the function of the device. CONSTITUTION: In an open rack type LNG vaporizer in which LNG inlet headers 10 and NG outlet headers 16 are connected by a plurality of LNG-vaporizing heating tubes 22 each of the outlet headers 16 is extended. To these extensions the upper ends of a plurality of LPG-vaporizing heating tubes 22' are connected and to NG-recovering inlet headers 10' the lower ends of the LPG-vaporizing heating tubes 22' are connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called open rack type liquefied natural gas having a function of vaporizing liquefied natural gas and a function of adding liquefied petroleum gas to the vaporized natural gas to adjust the amount of heat. The present invention relates to a vaporizer.

[0002]

2. Description of the Related Art Conventionally, an open rack vaporizer is widely known as a vaporizer for liquefied natural gas. This apparatus has an inlet header through which the liquefied natural gas flows, and an outlet header arranged above and parallel to the lower header through a large number of liquefied natural gas vaporization heat transfer tubes in the vertical direction. By connecting and liquefying natural gas in the inlet header, the liquefied natural gas in the inlet header is heated in the heat transfer pipes for liquefied natural gas by flowing seawater, which is a heating medium, outside the heat transfer pipes for liquefied natural gas vaporization. And the natural gas obtained thereby is recovered through the outlet header.

By the way, since the composition of methane or the like is not constant in the natural gas, when the natural gas is used as, for example, city gas, it is necessary to appropriately adjust the heat quantity of the natural gas to stabilize it. . This heat quantity adjustment is possible by adding an appropriate amount of liquefied petroleum gas having a high heat quantity to the natural gas.

More specifically, as means for realizing the above heat quantity adjustment, a method of adding liquefied petroleum gas to the natural gas in a vaporized state in advance or a method of adding liquefied natural gas and liquefied petroleum gas and then vaporizing both of them There are possible ways to do this. However, in the former method, in addition to the liquefied natural gas vaporization equipment, the liquefied petroleum gas vaporization equipment and the equipment for mixing both gases are required, and in the latter method, the liquefied natural gas and liquefied petroleum having boiling points greatly different from each other are required. Impurity adsorption equipment is required to avoid freezing of impurities such as methanol in the liquefied petroleum gas when vaporizing both of the gases, and either method is not preferable in terms of cost.

Therefore, in Japanese Patent Laid-Open No. 6-221783, the natural gas vaporized by the open rack type liquefied natural gas vaporizer is introduced into a plate fin type heat exchanger, and the plate fin type heat exchanger is introduced. Discloses a device for adding liquefied petroleum gas to the natural gas and heating it to vaporize the liquefied petroleum gas.

[0006]

In the device disclosed in the above publication, two types of heat exchangers, open rack type and plate fin type, must be installed independently of each other, and both heat exchangers are connected to each other. It is also necessary to provide piping for connecting the two in between, and the size and complexity of the entire device are increased, and there is the inconvenience that the initial cost increases. Moreover, since the structures of both heat exchangers are completely different, maintenance becomes complicated.

In view of such circumstances, the present invention provides a vaporizer which has a simple and compact structure and is capable of not only vaporizing liquefied natural gas but also adjusting the amount of heat of liquefied natural gas and also easy to maintain. To aim.

[0008]

According to the present invention, an inlet side pipe into which liquefied natural gas is introduced, and a lower end thereof is connected to the inlet side pipe, extends in the vertical direction, and a heating medium is flowed outward thereof. A plurality of liquefied natural gas vaporization heat transfer tubes, and an outlet side pipe that is connected to the upper ends of these liquefied natural gas vaporization heat transfer tubes and into which the liquefied natural gas vaporized natural gas is introduced. In the liquefied natural gas vaporizer provided, the outlet side pipe is provided with a liquefied petroleum gas supply section, and the outlet side pipe is vertically separated from the connection point with the liquefied natural gas vaporization heat transfer pipe. The upper ends of a plurality of heat transfer tubes for vaporizing liquefied petroleum gas, which extend and have a heating medium flowing to the outside thereof, are connected, and the heat transfer tubes for vaporizing liquefied petroleum gas are connected to the lower ends of the heat transfer tubes for vaporizing liquefied petroleum gas as described above. Liquefied natural gas Which are connected to collection piping for collecting the mixed gas of liquefied petroleum gas (claim 1).

More specifically, as the outlet side pipe,
A plurality of outlet headers and a common manifold that connects these outlet headers to each other are provided, and a plurality of liquefied natural gas vaporization heat transfer tubes are arranged along the longitudinal direction of each outlet header. It is preferable that the heat pipe is directly connected to each outlet header and the liquefied petroleum gas supply section is provided in the common manifold (claim 2).

In this case, each outlet header may be extended from the connection point with the liquefied natural gas vaporization heat transfer tube, and the liquefied petroleum gas vaporization heat transfer tube may be connected to this extended portion (claim 3). , The common manifold is extended from a connection point with the outlet header, an outlet header different from the outlet header is connected to the extension portion, and the liquefied petroleum gas vaporization heat transfer pipe is connected to the latter outlet header. (Claim 4)

Further, as the liquefied petroleum gas supply unit, a plurality of liquefied petroleum gas ejection holes are provided on a pipe wall, and a dispersion pipe for ejecting liquefied petroleum gas from the inside of the pipe to the outside of the pipe through the liquefied petroleum gas ejection holes is provided. By inserting it into the outlet side pipe, a more excellent effect as described later can be obtained (claim 5).

[0012]

According to the apparatus of the first aspect, liquefied natural gas (hereinafter referred to as LNG) supplied into the inlet side pipe.
Enters each LNG vaporization heat transfer tube, is heated and vaporized by heat exchange with the heating medium flowing to the outside, and enters the outlet side pipe. Natural gas recovered in the outlet side pipe (hereinafter referred to as NG.
It is not necessary to completely vaporize G, as long as it can be heated to a temperature at least above the temperature at which impurities such as methanol do not freeze. same as below. ) Is mixed with liquefied petroleum gas (hereinafter, referred to as LPG) in the outlet side pipe as it is, and enters into the LPG vaporization heat transfer pipe connected to the outlet side pipe. In this LPG vaporization heat transfer tube, the LPG contained in the above NG
Is heated and vaporized by heat exchange with the heating medium outside the pipe, and is recovered from the recovery pipe.

That is, the outlet side piping in this device is not only the outlet part in the LNG vaporizer but also NG and LPG.
It also has three roles as a mixing part with and an inlet part of the LPG vaporizer, and the whole device is integrated as one open rack heat exchanger.

More specifically, in the apparatus according to claim 2,
The NG vaporized by each LNG vaporization heat transfer tube enters the outlet header and is supplied into the common manifold.
G is mixed with the NG.

Here, in the apparatus according to the third aspect, the LPG supplied into the common manifold is distributed in each outlet header and mixed with NG, and the mixed fluid passes through the outlet header as it is and the outlet header. Connected to LPG
Enter the heat transfer tube for vaporization.

On the other hand, in the apparatus according to claim 4, L
The NG that has entered each outlet header from the NG vaporization heat transfer tube merges into the common manifold, is mixed with LPG, and passes through another outlet header that is connected to this common manifold.
Penetration into the heat transfer tube for PG vaporization.

In the apparatus according to the fifth aspect, the LPG is ejected from the inside of the dispersion pipe through the plurality of LPG ejection holes of the pipe wall to the outside of the pipe, so that the inside of the outlet side pipe is finer and more uniform. LPG is supplied, which promotes vaporization of LPG.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

The apparatus shown in this embodiment includes a plurality of horizontally extending inlet headers 10, and these inlet headers 10 are arranged in parallel in the horizontal direction.
One end of each inlet header 10 is closed, and the other ends are connected to each other via an inlet manifold 12 in a direction orthogonal to each inlet header 10. LNG supply ports 14 to LNG are provided at substantially the center of the inlet manifold 12. It is being introduced. That is, the inlet header 10 and the inlet manifold 12 constitute the inlet side pipe in the present invention.

An outlet header 16 is arranged above and parallel to each inlet header 10. One ends of the outlet headers 16 are connected to each other via a common manifold 18 parallel to the inlet manifold 12, and an LPG supply port 20 is provided at a substantially central portion of the common manifold 18.

A heat transfer panel in which a large number of LNG vaporization heat transfer tubes 22 are arranged in parallel is formed between the inlet header 10 and the outlet header 16. As shown in FIG. 2, each LNG vaporization heat transfer tube 22 extends vertically and communicates the insides of both headers 10 and 16. In this embodiment, an inner pipe 24 having a diameter smaller than that of the LNG vaporization heat transfer pipe 22 is arranged inside the lower half of each LNG vaporization heat transfer pipe 22, and between the two pipes 22, 24, Entrance header 1 above
An annular flow path 23 that communicates with the inside of 0 is formed. Specifically, as shown in FIG. 3, a plurality of (18 in the illustrated example) inner fins 29 are arranged side by side in the circumferential direction on the inner circumferential surface of the LNG vaporization heat transfer tube 22, and the tip surfaces of these inner fins 29 are arranged. Is in contact with the outer peripheral surface of the inner pipe 24, and at least a part (for example, the lower part) of both surfaces is fixed to each other by welding.

The heat transfer performance is improved by appropriately forming fins 28 on the outer peripheral surface of each LNG vaporization heat transfer tube 22, and the heat transfer performance is enhanced from the top to the bottom as shown by the arrow A in FIG. Seawater 30 or the like, which is a warm medium, is made to flow. Furthermore, a twisted heat transfer accelerator 2 is provided inside the inner tube 24 and inside the upper half of the LNG vaporization heat transfer tube 22.
6 is filled.

As a feature of the present invention, as shown in FIG.
Each outlet header 16 is extended in the longitudinal direction to the side opposite to the common manifold 18, and its extension end is closed, and the upper end of a plurality of LPG vaporization heat transfer tubes 22 'is connected to the extension. . These LPG vaporization heat transfer tubes 22
′ Are arranged in the longitudinal direction of the outlet header 16, and the lower ends of these LPG vaporization heat transfer tubes 22 ′ are at the respective outlet headers 1
It is connected to a recovery header 10 ′ that extends below 6 in a direction parallel to the outlet header 16. In these recovery headers 10 ′, the end portion on the side close to the inlet header 10 is closed, and the end portion on the opposite side is connected to the recovery manifold 12 ′ parallel to the inlet manifold 12, and the recovery manifold 12 ′. NG recovery port 1 at approximately the center of
4'is provided.

Like the LNG vaporization heat transfer tube 22, the LPG vaporization heat transfer tubes 22 'also extend vertically to communicate the insides of the headers 10' and 16 with each other, and the outer peripheral surfaces thereof from the top to the bottom. Seawater 30 or the like, which is a heating medium, is made to flow.

Next, the operation of this device will be described.

The LNG supplied from the LNG supply unit to the inlet manifold 10 is distributed in each inlet header 10. Then, in this embodiment, the LNG flows into the inner tubes 24 of the LNG vaporization heat transfer tubes 22 and the annular flow path 23 formed between the inner tubes 24 and the LNG vaporization heat transfer tubes 22. Also flows into. The distribution of the inflow amount is determined by the pressure loss inside the inner pipe 24 and the annular flow path 23, and is stabilized at a flow rate at which the inlet side pressure and the outlet side pressure are equal to each other. That is, the annular flow path 2
As the clearance dimension δ of 3 (FIG. 3) increases, the ratio of the inflow amount into the annular flow path 23 increases. In the lower part of the annular flow path 23 (that is, the LNG inlet part), L
In the vicinity of the wall surface of the NG vaporization heat transfer tube 22, LNG locally boils due to the heat from the LNG vaporization heat transfer tube 22 (so-called subcool boiling), and bubbles are generated. Further, in the upper part of the annular flow path 23, full-scale boiling occurs near the wall surface of the LNG vaporization heat transfer tube 22, and a gas phase and a liquid phase are mixed.
In any case, the forced convection boiling is promoted by the mixture of the gas phase and the liquid phase and the flow of LNG and NG from the bottom to the top, and the heat transfer coefficient is correspondingly increased. In this way, LN
LNG is vaporized in the G vaporization heat transfer tube 22 and enters the outlet header 16.

At this stage, it is not necessary to heat NG to 0 ° C. or higher, as long as it can be heated to a temperature at which impurities such as methanol in LPG do not freeze.

The outlet header 16 has an LPG supply port 2
The high heat quantity LPG supplied from 0 is distributed, and the heat quantity of the NG is adjusted by mixing this LPG with the NG from the LNG vaporization heat transfer tube 22. This mixed fluid flows through the outlet header 16 as it is, and descends within each LPG vaporization heat transfer tube 22 '. In the LPG vaporization heat transfer tube 22 ', the LPG is vaporized by heat exchange with a heating medium (seawater) flowing outside the tube, and NG, more accurately, a mixed gas of NG and PG is collected in the header 10'. And, it is recovered from the NG recovery port 14 'through the recovery manifold 12'.

In this apparatus, the outlet side piping consisting of the outlet header 16 and the common manifold 18 is provided in addition to the outlet section in the LNG vaporizer, and a mixer for LNG and LPG, L
The PG vaporizer also has three roles as an inlet, and the entire device is one open rack type heat exchanger. Therefore, different types of heat exchangers are installed individually as in the past. Compared with, the entire apparatus can be made smaller and simpler, the initial cost can be reduced, and the maintenance can be facilitated.

Particularly, as in this embodiment, if the outlet headers 16 are connected to a common common manifold 18 and then the common manifold 18 is provided with an LPG supply port 20, the LNG vaporization heat transfer tubes will be separated from each other. There is an advantage that the LPG can be more uniformly mixed with the NG that has entered the outlet header 16. Moreover, since each outlet header 16 is extended and the upper end of the LPG vaporization heat transfer tube 22 'is connected to the extended portion, it is possible to add the LPG vaporization section as it is without increasing the number of outlet headers 16. There is.

However, in the present invention, the above-mentioned exit header 16
The LPG and NG can be mixed even if the LPG supply unit is provided in the.

Next, a second embodiment will be described with reference to FIG.

In this embodiment, an open rack type LNG is used.
In the vaporizer, instead of extending the outlet header 16, the common manifold 18 is extended in its longitudinal direction, and an extension header 16 ′ different from the outlet header 16 ′ is provided in the extension portion thereof.
Are connected in parallel to the outlet header 16, and the upper ends of a plurality of LNG vaporization heat transfer tubes 22 arranged in the longitudinal direction are connected to each outlet header 16 ′.

In this apparatus, the NG that has risen to each outlet header 16 first joins the common manifold 18, and this NG
After the LPG is mixed with the LPG, the mixed fluid flows through the common manifold 18 as it is, and the LPG vaporization heat transfer tubes 22
It will descend in ´. According to this device, the LPG vaporizer can be added without modifying the existing outlet header 16, so that the LNG vaporizer having a large number of outlet headers 16 can be installed in the LNG vaporizer.
This is particularly advantageous when a PG vaporization function is added.

Next, a third embodiment will be described with reference to FIGS.

In this embodiment, instead of directly providing the LPG supply port 20 in the common manifold 18 in the apparatus shown in the first embodiment, the dispersion pipe 17 is inserted into the common manifold 18 from one end thereof. . The dispersion pipe 17 has a smaller diameter than the common manifold 18 and is housed in the common manifold 18 in a direction parallel to the common manifold 18. One end of this common manifold 18 is closed and inside the common manifold 18, and the other end (lower end in FIG. 6)
Is an LPG supply port 20 protruding from the dispersion pipe 17. A large number of LPG jet holes 17a having a small diameter are formed in the wall of the dispersion pipe 17, and the LPG supply port 20 is provided.
The LPG supplied into the dispersion pipe 17 from is sprayed (almost sprayed) into the common manifold 18 through the LPG spray holes 17a.

According to this apparatus, as compared with the case where the LPG is directly supplied from the single LPG supply port 20 into the common manifold 18 as shown in the first embodiment, the LPG is supplied more uniformly and finely. The gas can be supplied into the common manifold 18, and the effect of promoting the vaporization of LPG can be obtained. This effect is obtained by the second embodiment as shown in FIG.
The same can be obtained when the dispersion pipe 17 is inserted into the common manifold 18 of the apparatus shown in the embodiment.

The present invention is not limited to the above-mentioned embodiment, but can take the following modes as examples.

(1) In the present invention, the LNG vaporization heat transfer tube 2
Regardless of the internal structure of 2, the LNG vaporization heat transfer tube 22
Is only required to have a function of communicating both headers 10 and 16 and vaporizing LNG in the pipe. For example, as shown in FIG. 8, the inner tube 24 has a length substantially equal to that of the LNG vaporization heat transfer tube 22, and the heat transfer enhancer 2 is provided inside thereof.
6 may be inserted, or the inner tube 24 and the heat transfer promoting body 26 may be omitted. Similarly, the internal structure of the LPG vaporization heat transfer tube 22 'is not particularly limited. For example, as shown in FIG. 9, the heat transfer promoting body 26 may be inserted inside the LPG vaporization heat transfer tube 22'. Good.

(2) In the above embodiment, the outlet side pipe such as the outlet header 16 is arranged on the upper side, and the inlet side pipe such as the inlet header 10 and the collecting pipe such as the collecting header 10 'are arranged on the lower side. On the contrary, as shown in FIG. 10 as the fifth embodiment, conversely, the outlet side piping such as the outlet header 16 is arranged on the lower side,
The inlet side pipes such as the inlet header 10 and the recovery header 10 'and the recovery pipes may be arranged on the upper side. In this case, LN
In the G vaporization heat transfer tube 22, LNG descends, and in the LPG vaporization heat transfer tube 22 ', the mixed fluid of NG and LPG rises.

(3) In the present invention, regardless of the specific shape of each pipe, the inlet pipe or the outlet pipe may be divided into a plurality of pipes, and these pipes are branched more finely than the above-mentioned embodiments. You may let me. In this case as well, by connecting both the LNG vaporization heat transfer tube and the LPG vaporization heat transfer tube to the common outlet side pipe, the overall size and simplification of the device can be achieved.

(4) The specific numbers of the LNG vaporization heat transfer tubes and the LPG vaporization heat transfer tubes may be appropriately set according to the LNG processing amount and the LPG addition ratio.

[0043]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the LPG supply section is provided in the outlet side pipe of the open rack type LNG vaporizer, and a plurality of LPG vaporization heat transfer tubes are provided in the outlet side pipe in addition to the LNG vaporization heat transfer tube. Connect one end of the heat pipe,
By connecting a recovery pipe for recovering gas to the other end of the PG vaporization heat transfer pipe, the outlet pipe is connected to the outlet of the LNG vaporizer, the mixture of NG and LPG, and the LPG vaporizer. Since the entire device is made into one open rack type heat exchanger that also has three roles as the inlet part of the heat exchanger, the whole device can be compared with the conventional device in which different heat exchangers are individually installed. Further, the size and simplification can be achieved, the initial cost can be reduced, and the maintenance can be facilitated.

More specifically, in the apparatus according to claim 2, the outlet headers to which the LNG vaporization heat transfer tubes are connected are connected to a common manifold, and the LPG is connected to the common manifold.
Since the supply unit is provided, there is an effect that the LPG can be more uniformly mixed with the NG that has entered the outlet side pipe from each LNG vaporization heat transfer pipe.

Here, in the apparatus according to the third aspect, the outlet headers are extended as they are, and the LPG vaporization heat transfer pipes are connected to the extended portions, so that the outlet headers are not increased and the outlet headers are not increased. There is an effect that the LPG vaporization part can be added simply by extending the header.

On the other hand, in the apparatus according to the fourth aspect, the common manifold is extended, another outlet header is connected to this extended portion, and the LPG vaporization heat transfer tubes are connected to these outlet headers, respectively. The LPG vaporization section can be added while using the existing outlet header (that is, the outlet header to which the LNG vaporization heat transfer pipe is connected) without modification.

In the apparatus according to the fifth aspect, the dispersion pipe is inserted into the outlet side pipe, and the LPG is jetted into the outlet side pipe from the plurality of liquefied petroleum gas jet holes provided in the pipe wall of the dispersion pipe. Therefore, LPG can be supplied into the outlet side pipe in a finer and more uniform state, which has the effect of promoting vaporization of LPG.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an LNG vaporizer according to a first embodiment of the present invention.

FIG. 2 is a sectional front view showing an internal structure of a heat transfer tube for LNG vaporization in the LNG vaporizer.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an overall perspective view of an LNG vaporizer according to a second embodiment of the present invention.

FIG. 5 is an overall perspective view of an LNG vaporizer according to a third embodiment of the present invention.

FIG. 6 is a partial cross-sectional plan view showing a dispersion pipe inserted into a common manifold in the LNG vaporizer.

FIG. 7 is an overall perspective view of an LNG vaporizer in a fourth embodiment of the present invention.

FIG. 8 is a sectional front view showing a modified example of the internal structure of the LNG heat transfer tube for vaporization.

FIG. 9 is a sectional front view showing a modified example of the internal structure of the LPG vaporization heat transfer tube.

FIG. 10 is an overall perspective view of an LNG vaporizer in a fifth embodiment of the present invention.

[Explanation of symbols]

 10 inlet header (inlet side piping) 10 'recovery header (recovery piping) 12 inlet manifold (inlet side piping) 12' recovery header (recovery piping) 14 LNG supply port 16, 16 'outlet header 17 dispersion pipe 17a LPG ejection hole 18 Common manifold 20 LPG supply port 22 LNG vaporization heat transfer tube 22 'LPG vaporization heat transfer tube

Claims (5)

[Claims] 1. An inlet-side pipe into which liquefied natural gas is introduced, and one of upper and lower ends is connected to the inlet-side pipe, extends in the vertical direction, and has a plurality of heating media flowing outside thereof. Liquefied natural gas vaporization heat transfer tubes, and an outlet side pipe connected to the other end of these liquefied natural gas vaporization heat transfer tubes and into which the vaporized natural gas is introduced in these liquefied natural gas vaporization heat transfer tubes In the liquefied natural gas vaporizer equipped with, the outlet side pipe is provided with a liquefied petroleum gas supply part, and the outlet side pipe is located above and below the connection point with the liquefied natural gas vaporization heat transfer pipe. One end of a plurality of liquefied petroleum gas vaporization heat transfer tubes extending from the same side is connected from the same side as the liquefied natural gas vaporization heat transfer tubes, and these liquefied petroleum gas vaporization heat transfer tubes are connected to the other ends of these liquefied petroleum gas vaporization heat transfer tubes. Liquefaction from the heat tube A liquefied natural gas vaporizer characterized in that a recovery pipe is connected to recover a mixed gas of natural gas and liquefied petroleum gas. 2. The liquefied natural gas vaporizer according to claim 1, comprising a plurality of outlet headers as the outlet side pipe, and a common manifold communicating these outlet headers with each other, and the outlet headers in the longitudinal direction. A plurality of liquefied natural gas vaporization heat transfer tubes are arranged along with each other, and these liquefied natural gas vaporization heat transfer tubes are directly connected to each outlet header, and the liquefied petroleum gas supply section is provided in the common manifold. Characterized liquefied natural gas vaporizer. 3. The liquefied natural gas vaporizer according to claim 2, wherein each outlet header is extended from a connection point with the liquefied natural gas vaporization heat transfer pipe, and the extended portion is provided with the liquefied petroleum gas vaporization heat transfer pipe. A liquefied natural gas vaporizer characterized by being connected to. 4. The liquefied natural gas vaporizer according to claim 2, wherein the common manifold is extended from a connection point with the outlet header, and an outlet header different from the outlet header is connected to the extended portion. A vaporizer for liquefied natural gas, characterized in that the heat transfer pipe for vaporizing liquefied petroleum gas is connected to the latter outlet header. 5. The liquefied natural gas vaporizer according to any one of claims 1 to 4, wherein a plurality of liquefied petroleum gas ejection holes are provided in a pipe wall as the liquefied petroleum gas supply unit, and the liquefaction is conducted from inside the pipe. A vaporizer for liquefied natural gas, characterized in that a dispersion pipe for ejecting liquefied petroleum gas outside the pipe through a petroleum gas ejection hole is inserted into the outlet side pipe.