JP5740122B2 - LNG vaporization equipment - Google Patents

Description

  The present invention relates to an LNG vaporization facility in an LNG plant.

  In recent years, in response to the global warming problem caused by the increase in carbon dioxide, it has been demanded to strengthen efforts for environmental conservation on a global scale. In Japan, options for energy suppliers are diversifying as regulations on the energy industry progress alongside environmental initiatives. Against this background, the demand for LNG, a clean energy, has been increasing year by year, and it has been evaluated as a fuel for industrial use, including power generation and city gas.

An LNG plant sends LNG stored in an LNG tank to a vaporizer via a supply line by a pump, where LNG is vaporized by heat exchange, and each supply destination (for example, a thermal power plant or the like uses LNG as fuel) The LNG plant is generally known to be able to produce two types of low-pressure gas and high-pressure gas according to the purpose of the supply destination (for example, patents). Reference 1, 2 etc.) .

JP 2008-208862 A JP 2006-57755 A

  In this type of LNG plant, from the viewpoint of stable supply, a preliminary vaporizer is provided for each of the low pressure gas generation vaporizer and the high pressure gas generation vaporizer, and during regular inspection of the normally used vaporizer It is possible to respond to unforeseen situations such as accidents and breakdowns at any time, but it is also possible to install two things (one each for low pressure and high pressure) that can only be operated at such times. It is extremely wasteful in terms of cost.

  In view of this point, in recent years, only one high-pressure gas generating vaporizer is provided as a preliminary vaporizer, and when the normally used high-pressure gas generating vaporizer is stopped, the vaporizer is switched to the spare high-pressure gas generating vaporizer. Even if the high pressure gas is generated and the low pressure gas generation vaporizer is stopped, the high pressure gas is generated by switching to the preliminary high pressure gas generation vaporizer, and the low pressure gas is generated by reducing the pressure. Has been tried. However, even in this method, when the high pressure gas is reduced to a low pressure gas, the temperature of the gas decreases with adiabatic expansion, so that there is a problem that a gas heater must be newly installed. There is also a problem of wasted power costs. Furthermore, in a vaporizer of a type that vaporizes LNG by heat exchange with seawater that is normally used, it takes time to start up as a spare unit unless it is on standby in the state of seawater pump operation and LNG supply pipe cooling and holding There was a drawback.

  The present invention has been made in view of the above problems, and has a preliminary vaporizer in an LNG vaporization facility including a low pressure system having a low pressure gas generation vaporizer and a high pressure system having a high pressure gas generation vaporizer. The spare system is connected to the low pressure system so as to straddle the low pressure gas generating vaporizer, and is also connected to the high pressure system so as to straddle the high pressure gas generating vaporizer. Either LNG in the system or LNG in the high-voltage system can be selectively supplied.

  According to the above configuration, the supply of LNG to the low pressure gas generation vaporizer is stopped, and the LNG is supplied to the preliminary vaporizer, thereby switching from the low pressure gas generation vaporizer to the preliminary vaporizer, Low-pressure gas is generated in the preliminary vaporizer. In addition, by stopping the supply of LNG to the high pressure gas generating vaporizer (LNG boosted from LNG in the low pressure system) and supplying the LNG to the preliminary vaporizer, preliminary vaporization from the high pressure gas generating vaporizer is performed. The high-pressure gas is generated in the preliminary vaporizer. In addition, the low-pressure gas generated in the pre-vaporizer is sent to the low-pressure system, and the high-pressure gas generated in the pre-vaporizer is sent to the high-pressure system. The gas and the high-pressure gas are stably supplied to the supply destination.

  Further, the present invention provides a connection part to a low-pressure system on the upstream side of the low-pressure gas generation vaporizer, a connection part to the low-pressure system on the downstream side of the low-pressure gas generation vaporizer, and a high-pressure gas generation vaporization. It is possible to adopt a configuration in which a switching valve is provided in each of the connection portion to the high pressure system on the upstream side of the gas generator and the connection portion to the high pressure system on the downstream side of the vaporizer for high pressure gas generation.

  According to the above configuration, by appropriately opening and closing the four switching valves, switching from the low pressure gas generating vaporizer to the preliminary vaporizer or switching from the high pressure gas generating vaporizer to the preliminary vaporizer is performed as appropriate. be able to. Further, since the pressures of the low pressure system and the high pressure system can be obtained, there is no need to newly install a decompression facility and a gas heater as in the case where the high pressure gas generating vaporizer is used as a spare for the low pressure system. Furthermore, when a type of vaporizer that vaporizes LNG by heat exchange with hot water heated by steam (for example, a steam ejector type vaporizer) is used as a preliminary vaporizer, rapid start-up is possible, so startup can be performed quickly. The gas supply can be restored.

  As described above, the present invention uses spare carburetors in the low-pressure system and the high-pressure system. Therefore, the number of carburetors is reduced compared to the case where spare carburetors are provided. However, it is extremely useful in terms of construction costs.

  Further, it is not necessary to newly install a decompression equipment and a gas heater as in the case where the high-pressure gas generating vaporizer is used as a spare for the low-pressure system. Furthermore, when using a type of vaporizer that vaporizes LNG by heat exchange with hot water heated by steam (for example, a steam ejector type vaporizer), the gas supply can be restored with a quick start-up, which is extremely useful. is there.

The conceptual diagram of the LNG plant which concerns on this embodiment is shown. The conceptual diagram of the combined plant of the LNG plant and oil refinery plant which concerns on this embodiment is shown.

  Hereinafter, an LNG plant including an embodiment of an LNG vaporization facility according to the present invention will be described with reference to FIG.

  The LNG plant according to the present embodiment stores the LNG loaded on the LNG ship 1 in the LNG tank 3 via the receiving line 2, and the LNG in the LNG tank 3 is supplied by the first pump 4 via the supply line 5. In this plant, the LNG is sent to an LNG vaporization facility, where LNG is vaporized by heat exchange and LNG gas is sent to each supply destination by a pipeline, or the LNG is shipped in a lorry form without being vaporized.

  The supply line 5 includes a first supply line 5a for generating low-pressure gas (for example, about 1 MPa), a second supply line 5b for generating high-pressure gas (for example, about 5 MPa), and a first supply line 5b for shipping the lorry. Branches to three supply lines 5c.

  The first supply line 5 a is connected to the first vaporizer 7 via the control valve 6, and the low-pressure gas generated by the first vaporizer 7 is sent to the supply destination via the first pipeline 8. On the other hand, the second supply line 5b is connected to the second vaporizer 11 via the second pump 9 and the regulating valve 10 for further boosting the LNG boosted by the first pump 4, and the second vaporizer 11 The high-pressure gas generated in (1) is sent to the supply destination via the second pipeline 12.

  A first preliminary supply line 5a ′ is branched from the first supply line 5a, and the first preliminary supply line 5a ′ is connected to the preliminary vaporizer via the first switching valve 13, the check valve 14 and the control valve 15. The low-pressure gas connected to 16 and generated by the preliminary vaporizer 16 is sent to the first pipeline 8 through a first relay line 17 having a second switching valve 18. On the other hand, the second auxiliary supply line 5b ′ is branched from the second supply line 5b and downstream of the second pump 9, and the second auxiliary supply line 5b ′ The high-pressure gas connected to the preliminary vaporizer 16 via the control valve 15 and generated by the preliminary vaporizer 16 passes through the second relay line 20 having a check valve 21 and a fourth switching valve 22. Two pipelines 12 are sent.

  The first vaporizer 7 and the second vaporizer 11 include a hot water vaporizer that vaporizes LNG by heat exchange with seawater, more specifically, an intermediate medium (propane, butane, chlorofluorocarbon, etc. by heat exchange with seawater. ) Is vaporized, and an intermediate medium type vaporizer is used that vaporizes LNG in a pipe disposed in the vapor. Since this vaporizer requires less seawater than an open rack type vaporizer, it has a feature that the piping system is small, the overall size is small, and space can be saved.

  On the other hand, the preliminary vaporizer 16 is a hot water vaporizer that vaporizes LNG by heat exchange with steam, more specifically, water vapor is supplied to the water via a steam ejector, and is disposed in the heated warm water. A steam ejector type vaporizer that vaporizes LNG in the pipe is used. This vaporizer has a feature that it has high heat exchange performance by vigorously stirring hot water by air sucked from a steam ejector.

  The LNG plant is configured as described above, and the first supply line 5a and the first pipeline 8 correspond to the “low pressure system” according to the present invention, and the second supply line 5b and the second pipeline 12 are the main lines. The first auxiliary supply line 5a ′, the second auxiliary supply line 5b ′, the first relay line 17 and the second relay line 20 correspond to the “standby system” according to the present invention. The first auxiliary supply line 5a ′ corresponds to the “connection portion to the low-pressure system on the upstream side of the vaporizer for low-pressure gas generation in the auxiliary system” according to the present invention, and the first relay line 17 according to the present invention. This corresponds to the “connection portion to the low-pressure system on the downstream side of the vaporizer for low-pressure gas generation in the spare system”, and the second preliminary supply line 5b ′ according to the present invention is “vaporization for high-pressure gas generation in the spare system”. High pressure upstream of the vessel Corresponds to a connection portion "of the integration, the second relay line 20 of the" pre-strains according to the present invention, which corresponds to a connection portion "of the high pressure system on the downstream side of the high-pressure gas generator for the vaporizer.

  Normally, LNG is supplied only to the first vaporizer 7 and the second vaporizer 11 by closing the first to fourth switching valves 13, 18, 19, and 22. Moreover, the upstream sides of the first vaporizer 7 and the second vaporizer 11, that is, the first supply line 5a and the second supply line 5b are respectively connected via the first preliminary supply line 5a ′ and the second preliminary supply line 5b ′. Although connected, the first switching valve 13 and the third switching valve 19 are closed, so that the LNG boosted by the second pump 9 does not flow into the low-pressure system, and the first carburetor 7 The first vaporizer 11 and the second pipeline 12 are respectively connected to the downstream side of the second vaporizer 11 via the first relay line 17 and the second relay line 20. Since the fourth switching valve 22 is closed, the high pressure gas does not flow into the low pressure system. As a result, low pressure gas is generated in the first vaporizer 7 and high pressure gas is generated in the second vaporizer 11.

  And when the 1st vaporizer 7 stops for reasons, such as an inspection and a failure, while closing the control valve 6 and opening the 1st switching valve 13 and the 2nd switching valve 18, LNG becomes the preliminary vaporizer 16 and It is supplied only to the second vaporizer 11. Moreover, the upstream side of the preliminary vaporizer 16 and the second vaporizer 11, that is, the first preliminary supply line 5a ′ and the second supply line 5b are connected via the second preliminary supply line 5b ′. Since the third switching valve 19 is closed, the LNG boosted by the second pump 9 does not flow into the low-pressure system, and also downstream of the preliminary vaporizer 16 and the second vaporizer 11, that is, Although the 1st relay line 17 and the 2nd pipeline 12 are connected via the 2nd relay line 20, since the 4th switching valve 22 is closed, high pressure gas does not flow into a low pressure system. . As a result, the pre-vaporizer 16 generates low-pressure gas, and the second vaporizer 11 generates high-pressure gas.

  On the other hand, when the second carburetor 11 stops for reasons such as inspection and failure, the control valve 10 is closed and the third switching valve 19 and the fourth switching valve 22 are opened from the normal state. Only the first vaporizer 7 and the preliminary vaporizer 16 are supplied. Moreover, each upstream side of the first vaporizer 7 and the preliminary vaporizer 16, that is, the first supply line 5a and the second preliminary supply line 5b ′ are connected via the first preliminary supply line 5a ′. Since the first switching valve 13 is closed, the LNG boosted by the second pump 9 does not flow into the low-pressure system, and also downstream of the first vaporizer 7 and the preliminary vaporizer 16, that is, The first pipeline 8 and the second relay line 20 are connected via the first relay line 17, but the high pressure gas does not flow into the low pressure system because the second switching valve 18 is closed. . As a result, low pressure gas is generated in the first vaporizer 7 and high pressure gas is generated in the preliminary vaporizer 16.

  Thus, according to the LNG plant concerning this embodiment, a preliminary vaporizer can be used by a low-pressure system and a high-pressure system by appropriate control of change-over valves 13, 18, 19, and 22 compared with the past. As the number of vaporizers is reduced, the construction site for the LNG plant can be reduced, and the construction cost can be reduced.

  Further, each switching valve 13, 18, 19, 22 in the LNG vaporizer is changed from the high pressure system (second preliminary supply line 5b ′, second relay line 20) to the low pressure system (first preliminary supply line 5a ′, first relay). The system is configured so as to sequentially operate under a predetermined condition at the time of switching so as not to flow into the line 17). Even if the valves 13, 18, 19, and 22 malfunction or fail, the high pressure side (second preliminary supply line 5b ′) LNG is transferred to the low pressure side (first preliminary supply line 5a ′), and the high pressure side (second relay). Line 20) Check valves 14 and 21 are provided in each to prevent the gas from flowing into the low pressure side (first relay line 17) to prevent inflow.

  In addition, although it is an irregular usage method, since the LNG is also supplied to the preliminary vaporizer 16 by opening the first switching valve 13 and the second switching valve 18 from the normal state, the low-pressure gas is supplied to the preliminary vaporizer. While the production can be increased by 16, the LNG boosted by the second pump 9 is also supplied to the preliminary carburetor 16 by opening the third switching valve 19 and the fourth switching valve 22 from the normal state. Therefore, the production of high-pressure gas can be increased by the amount corresponding to the preliminary vaporizer 16.

  By the way, the LNG plant according to the present embodiment replaces a part of the refinery site with the site of the LNG plant in accordance with the recent increase in demand for LNG, and takes the form of a combined plant attached to the existing refinery. Is. This is shown in FIG.

  Refinery A has a crude oil tank, an atmospheric distillation unit, a vacuum distillation unit, a naphtha hydrodesulfurization unit, a catalytic reformer, a debenzene unit, a kerosene hydrodesulfurization unit, a light oil deep hydrodesulfurization unit, and heavy gas oil. Various oil production facilities 30 such as a hydrocracking apparatus, a heavy oil direct desulfurization apparatus, and a heavy oil fluid catalytic cracking apparatus are installed. Since these facilities are well known, a detailed description is omitted, and it should be noted that the facilities vary slightly depending on the scale of the refinery.

  Since various oil refineries require cooling in carrying out the oil refinement process, seawater is taken from them and used as cooling water. Seawater is taken from a water intake 31 by a seawater intake facility (not shown), supplied to various oil refineries 30 through a water intake line 32, and the seawater subjected to heat exchange through a cooling system is discharged (drainage). It returns to the sea from the water discharge (drainage) port 34 through the line 33.

  And the seawater used by the 1st and 2nd vaporizers 7 and 11 of the LNG plant B is supplied from the intake line 32 of the refinery A. That is, the supply line 35 is branched from the intake line 32 so that part of the seawater flows to the first and second vaporizers 7 and 11. Further, the seawater after heat exchange is returned to the intake line 32. That is, the seawater after heat exchange from the first and second vaporizers 7 and 11 is returned to the intake line 32 through the return line 36.

  The return line 36 is connected to the downstream side of the water intake line 32 with respect to the supply line 35. Therefore, the seawater that reaches the first and second vaporizers 7 and 11 through the supply line 35 is cooled by the cold heat of LNG. The cooled seawater flows into the intake line 32 through the return line 36. As a result, the temperature of the entire seawater from the intake line 32 to the various oil refineries 30 decreases, and this seawater becomes the cooling water for the various oil refineries 30. As a result, the cooling efficiency in the various oil refineries 30 is increased.

  Moreover, the seawater heat-exchanged through the cooling system in the various oil refineries 30 has a water temperature that is higher than that at the time of supplying the cooling water due to heat input, but since the seawater was originally cooled by the cold heat of LNG, The temperature can be kept lower than when not passing through the first and second vaporizers 7 and 11. As a result, it is possible to reduce the temperature of seawater (ie, wastewater temperature) that is heat-exchanged through the cooling system, which is an effective environmental measure against hot wastewater.

  On the other hand, the steam used in the preliminary vaporizer 16 of the LNG plant B uses steam generated from various oil refineries 30 when the oil refinement process is performed. That is, a supply line 37 is piped from various oil refineries 30 so that the generated water vapor flows to the preliminary vaporizer 16.

  Thus, when a part of the site of refinery A is replaced with the site of LNG plant B and LNG plant B is added to the existing refinery A, the seawater intake facility of the existing refinery A is installed in the LNG plant B. Since ancillary equipment such as wastewater treatment equipment or steam generation equipment can be used, the construction site of the plant B can be further reduced together with the use of the preliminary vaporizer 16, and the construction cost can be further reduced. .

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  In the above embodiment, LNG is temporarily stored in the LNG tank 3 and LNG is supplied to each of the vaporizers 7 and 11 from here, but it may be supplied directly from, for example, an LNG ship.

  Moreover, in the said embodiment, although the one supply line 5 is divided into the 1st supply line 5a and the 2nd supply line 5b, it is made to supply LNG, but the 1st supply line 5a and the 2nd supply line Lines 5b may be independent of each other.

  Moreover, in the said embodiment, although it relies on the refinery A for the supply source of the seawater with respect to the vaporizers 7 and 11, and the supply source of the water vapor | steam with respect to the preliminary vaporizer 16, when it is a LNG plant single, seawater intake equipment Ancillary equipment such as waste water treatment equipment or steam generation equipment is naturally provided, and seawater and water vapor will be supplied from here.

  In addition, even in the case of taking the form of a complex plant, the point is that a predetermined manufacturing plant (for example, for example, which takes in seawater and uses it as cooling water in carrying out a predetermined manufacturing process and can generate water vapor in the manufacturing process) (Chemical plant, steel plant, thermal power / nuclear power plant) may be used, and the plant is not limited to a refinery (refining plant).

  Moreover, in the said embodiment, the inspection, failure, etc. of the 1st or 2nd vaporizers 7 and 11 are mentioned as a trigger of the operation switching from the 1st or 2nd vaporizers 7 and 11 to the preliminary vaporizers 16. However, the present invention can also be applied to a case where seawater is not supplied to the first or second vaporizers 7 and 11 due to a malfunction of the intake system.

  In the above embodiment, an intermediate medium type vaporizer is used as a normally used vaporizer, and a steam ejector type vaporizer is used as a spare vaporizer. However, the present invention is not limited to these. Absent. These can be selected as appropriate, including open rack vaporizers and submerged vaporizers.

  However, if a steam ejector type vaporizer is used as at least a spare vaporizer, there are the following merits on the premise that it is a combined plant with the above-mentioned refinery or the like. For example, if the spare carburetor is a type of vaporizer that vaporizes LNG by heat exchange with seawater, the spare carburetor that can be switched in the event of an emergency of the usual carburetor can be immediately used. In order to be able to operate, it is necessary to always allow seawater to pass through a spare vaporizer even during normal times. This is because if the LNG is allowed to flow into the vaporizer without passing seawater, the seawater that is still in the vaporizer may freeze and the vaporizer may burst due to its volume expansion. If you try to answer it, the power of the equipment will be wasted, and the running cost will get worse. On the other hand, if the auxiliary vaporizer is a type of vaporizer that vaporizes LNG by heat exchange with water vapor as in the above embodiment, the vapor required to be able to operate the vaporizer at any time. Can be easily and inexpensively received from the manufacturing plant.

  A ... refinery (manufacturing plant), B ... LNG plant, 3 ... LNG tank, 4 ... first pump, 5 ... supply line, 5a ... first supply line (supply line for low pressure gas generation), 5a '... first Preliminary supply line (preliminary supply line for low-pressure gas generation), 5b ... second supply line (supply line for high-pressure gas generation), 5b '... second preliminary supply line (preliminary supply line for high-pressure gas generation), 5c ... third Supply line (LNG supply line), 7 ... First vaporizer (vaporizer for low-pressure gas generation), 8 ... First pipeline (low-pressure gas transfer pipeline), 9 ... Second pump, 11 ... Second vaporizer (Vaporizer for high-pressure gas generation), 12 ... second pipeline (pipeline for high-pressure gas transfer), 13 ... first switching valve, 14 ... check valve, 16 ... preliminary vaporizer, 17 ... first relay line, 18 ... second switching valve, 19 ... third cut Valves, 20 ... second relay line, 21 ... check valve, 22 ... fourth switching valve, 30 ... oil refinery, 32 ... water intake line, 35 supply line (seawater supply line), 36 ... return line (seawater return line) 37 ... Supply line (steam supply line)

Claims (3)

  In an LNG vaporization facility including a low-pressure system having a low-pressure gas generating vaporizer and a high-pressure system having a high-pressure gas generating vaporizer, a spare system having a preliminary vaporizer straddles the low-pressure gas generating vaporizer. Connected to the low-pressure system and also connected to the high-pressure system so as to straddle the carburetor for high-pressure gas generation, and either LNG in the low-pressure system or LNG in the high-pressure system is selectively selected with respect to the spare system. LNG vaporization equipment characterized by being configured to be capable of being supplied to the LNG.   Of the spare system, the connection to the low-pressure system upstream of the low-pressure gas generator, the connection to the low-pressure system downstream of the low-pressure gas generator, and the high pressure upstream of the high-pressure gas generator The LNG vaporization equipment according to claim 1, wherein a switching valve is provided in each of a connection part to the system and a connection part to the high-pressure system on the downstream side of the vaporizer for high-pressure gas generation. A predetermined manufacturing plant capable of generating water vapor in performing a predetermined manufacturing process is an adjacent LNG vaporization facility,
As a vaporizer for low pressure gas generation and a vaporizer for high pressure gas generation, a vaporizer of the type that vaporizes LNG by heat exchange with seawater is used, while as a preliminary vaporizer, by heat exchange with hot water heated by steam. The LNG vaporization facility according to claim 1 or 2 , wherein a vaporizer of a type that vaporizes LNG is used, and steam is supplied as a heat source for heat exchange in the preliminary vaporizer.

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