Fuel Vaporizer

Abstract

[Problem] To provide a technique whereby equipment for vaporizing liquid fuel is used and cold seawater adjusted to the desired temperature is supplied to cold / heat-using equipment. [Solution] Fuel vaporization equipment that vaporizes liquid fuel, wherein an open rack vaporizer (1) vaporizes the liquid fuel using seawater, and a seawater supply line (301) supplies seawater to the open rack vaporizer (1). A cold seawater supply line (402) supplies cold / heat-using equipment (5) with cold seawater that has decreased in temperature due to heat exchange with liquid fuel in the open rack vaporizer (1), and a circulation line (401) adjusts the temperature of the cold seawater by resupplying some of the cold seawater to the open rack vaporizer (1). [Selected drawing] Figure 2

Description

[Technical field]

[0001] The present invention relates to a technology for utilizing cold energy obtained when vaporizing liquefied fuel. [Background technology]

[0002] Liquefied natural gas (LNG) and liquefied hydrogen are used as fuels. In order to use fuel, it is necessary to vaporize the liquefied fuel and supply it in a gaseous state to the fuel consumption equipment. One type of equipment for vaporizing liquefied fuel is the open rack vaporizer (ORV), which vaporizes liquefied fuel supplied inside a panel made up of multiple heat transfer tubes by flowing seawater, a heating medium, along the outer surface of the panel.

[0003] On the other hand, in liquefied fuel vaporization equipment, the temperature of the heating medium decreases due to heat exchange with the liquefied fuel, so technologies have been proposed to utilize the cold energy accumulated in the heating medium for temperature regulation in plant factories, etc. (e.g., Patent Documents 1 and 2).

[0004] However, in order to reduce the impact on the environment, there is a restriction on the minimum temperature of seawater discharged from the storage base where liquid fuel is stored. Also, while the temperature of seawater may change depending on the weather and season, the vaporization equipment has the highest priority to operate to vaporize the required amount of liquefied fuel. Therefore, the temperature of seawater discharged from the ORV may also change depending on these conditions. For these reasons, the temperature of the low-temperature seawater (cold seawater) discharged from the ORV may not match the temperature required by cold energy utilization facilities such as plant factories. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-31964 A [Patent Document 2] Registered Utility Model No. 3209642 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a technology that utilizes a liquefied fuel vaporization facility to supply cold seawater adjusted to a desired temperature to a cold energy utilization facility. [Means for solving the problem]

[0007] The present invention provides a fuel vaporization system for vaporizing a liquefied fuel, comprising: an open rack vaporizer that vaporizes the liquefied fuel by flowing seawater along outer surfaces of a plurality of heat transfer tubes to which the liquefied fuel is supplied; a seawater supply line for supplying seawater to the open rack vaporizer; a cold seawater supply line that supplies the cold seawater used for vaporizing the liquefied fuel in the open rack vaporizer and whose temperature has been reduced by heat exchange with the liquefied fuel to a cold energy utilization facility that utilizes the cold energy of the cold seawater; a circulation line for resupplying a portion of the cold seawater discharged from the open rack vaporizer to the open rack vaporizer to reduce the temperature of the cold seawater to a preset temperature. 、 a cold seawater pit for receiving the cold seawater discharged from the open rack vaporizer, the cold seawater supply line supplies the cold seawater in the cold seawater pit to the cold heat utilization facility, and the circulation line re-supplies the cold seawater in the cold seawater pit to the open rack vaporizer; a seawater supply pit is provided in the seawater supply line, into which seawater flowing through the seawater supply line flows, and which is provided adjacent to the cold seawater pit via a partition wall and configured to receive the cold seawater overflowing from an upper end of the partition wall, and the upper end surface of the partition wall, which is an area into which the cold seawater flows from the cold seawater pit into the seawater supply pit, constitutes the circulation line; By increasing or decreasing the flow rate of the seawater flowing into the seawater supply pit, the flow rate of the cold seawater resupplied from the cold seawater pit to the open rack vaporizer via the seawater supply pit is increased or decreased, thereby adjusting the temperature of the cold seawater; It is characterized by:

[0008] The fuel vaporization system may have the following features. (a) The cold energy utilization facility is an aquaculture tank that uses the cold energy of the cold seawater to regulate the temperature of water for cultivating fish and shellfish, or a plant factory that uses the cold energy to regulate the temperature of at least one of the plant growth atmosphere, growth soil, or culture water. (b) The liquefied fuel is liquefied natural gas or liquefied hydrogen. (c )beforeThe apparatus is provided with an uncooled seawater supply line for supplying seawater that has not been cooled by the open rack evaporator to the cold energy utilization equipment. Effect of the Invention

[0009] According to the present invention, a circulation line is provided for re-supplying to the open rack vaporizer a portion of the cold seawater whose temperature has been reduced by heat exchange for vaporizing liquefied fuel in the open rack vaporizer, so that the temperature of the cold seawater supplied to the cold energy utilization equipment can be adjusted to the desired temperature. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a configuration diagram of a conventional LNG vaporization facility. [Diagram 2] 1 is a configuration diagram of an LNG vaporization facility according to an embodiment. FIG. [Diagram 3] FIG. 11 is a configuration diagram of an LNG vaporization facility according to a second embodiment. [Figure 4] FIG. 11 is a configuration diagram of an LNG vaporization facility according to a third embodiment. [Diagram 5] FIG. 11 is a configuration diagram of an LNG vaporization facility according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Before describing the configuration of a fuel vaporization system according to an embodiment, a configuration example of a fuel vaporization system according to a conventional configuration will be described with reference to Fig. 1. In each of the drawings shown below, an LNG vaporization system that vaporizes liquefied natural gas (LNG) will be described as an example of a liquefied fuel.

[0012] The LNG vaporization facility vaporizes the LNG stored in the LNG tank 2 in an open rack vaporizer (ORV) 1, and distributes the vaporized fuel gas through the fuel gas supply line. N The electricity is then supplied to consumers through this network. ORV1 has a known configuration in which seawater is caused to flow down along the outer surface of a panel 11 composed of a number of heat transfer tubes to which LNG is supplied from an LNG tank 2, and the LNG is vaporized through heat exchange with the seawater to obtain fuel gas.

[0013] The ORV 1 shown in FIG. 1 uses seawater (eg, 20° C.) taken in by a water intake pump 31 as seawater for vaporizing LNG. As a specific configuration example, seawater taken in by a water intake pump 31 is supplied toward an ORV seawater supply line 301 connected to the ORV 1. The supply flow rate of seawater is adjusted using a flow rate detector 322 and a flow rate control valve 321 provided in the ORV seawater supply line 301. The seawater used for vaporizing the LNG is discharged toward a water outlet via an ORV discharge line 302.

[0014] In an LNG vaporization facility having the above-described configuration, seawater whose temperature has been reduced by heat exchange with the LNG is obtained in the ORV 1, and the cold energy of this seawater can be utilized in various cold energy utilization facilities. Examples of uses for cold energy in cold energy utilization equipment include regulating the temperature of culture water in fish and shellfish culture tanks, and regulating the temperature of at least one of the plant growth atmosphere, growth soil, and culture water in a plant factory.

[0015] For example, the water for salmon farming is preferably below 20°C, and for abalone farming it is preferably below 25°C. Also, the soil for strawberry cultivation and the water supplied to said soil are preferably below 15°C. Thus, in cold energy utilization facilities, there are suitable temperatures depending on the purpose of using the cold energy.

[0016] However, in order to reduce the impact on the environment, there is a restriction on the minimum temperature of the seawater discharged outside, for example, the temperature of the seawater discharged from the outlet needs to be maintained at about 20°C. On the other hand, since ORV1 uses a large amount of seawater, it may be difficult to utilize the entire amount of seawater discharged from ORV1 in the cold energy utilization equipment.

[0017] Therefore, even if a portion of the seawater discharged from ORV1 is supplied to the cold energy utilization facility, most of the remaining seawater must be discharged to the outside as it is. If a large amount of low-temperature seawater is discharged, there is a risk that the temperature of the seawater discharged to the outlet will fall below the allowable temperature. For this reason, in the conventional LNG vaporization facility shown in Figure 1, for example, the seawater temperature at the outlet of ORV1 can only be reduced to about 17°C.

[0018] In addition, the temperature of seawater may change depending on the weather and season. On the other hand, the LNG vaporization facility places the highest priority on operating to vaporize the LNG at a flow rate that meets the demands of the consumer side. Therefore, when the temperature of the supplied seawater changes, it may be difficult to maintain the temperature of the seawater discharged from ORV1 at the temperature required by the cold energy utilization facility.

[0019] As described above, with conventional LNG vaporization facilities, it was sometimes difficult to stably supply cold seawater at the temperature required for cold energy utilization facilities all year round. The LNG vaporization equipment of this embodiment addresses the above-mentioned problems and has a configuration that can stably supply cold seawater at the temperature required by the cold energy utilization equipment while minimizing the impact on the environment.

[0020] Hereinafter, an example of the overall configuration of an LNG vaporization facility according to an embodiment will be described with reference to Fig. 2. The LNG vaporization facility shown in Fig. 2 is configured to be able to supply a portion of the cold seawater discharged from the ORV 1 to a cold energy utilization facility 5 including an aquaculture tank and a plant factory. 2 to 5 described below, components common to those described using FIG. 1 are denoted by the same reference numerals as those shown in FIG.

[0021] In the LNG liquefaction facility shown in Figure 2, the flow path of seawater discharged from ORV 1 branches into an ORV discharge line 302a for discharging cold seawater toward a discharge outlet, and a cold seawater pit line 302b through which cold seawater flows to be supplied to the cold energy utilization facility 5. The ORV discharge line 302a discharges the cold seawater toward the outlet. Meanwhile, a cold seawater pit 41 is provided downstream of the cold seawater pit line 302b, and the cold seawater supplied to the cold energy utilization facility 5 is received in the cold seawater pit 41.

[0022] Between the cold seawater pit 41 and the cold energy utilization facility 5, a cold seawater supply line 402 is provided for supplying cold seawater to the cold energy utilization facility 5. The cold seawater that flows into the cold seawater pit 41 is supplied to the cold energy utilization facility 5 via the cold seawater supply line 402 by a liquid feed pump 44 provided upstream of the cold seawater supply line 402. The flow rate of the cold seawater supplied to the cold energy utilization facility 5 is adjusted using a flow rate detection unit 432 and a flow rate control valve 431 provided in the cold seawater supply line 402. In addition, an opening / closing valve 433 is provided in the cold seawater supply line 402, which allows the supply and stopping of cold seawater to the cold energy utilization facility 5 to be performed.

[0023] Furthermore, a circulation line 401 for resupplying the cold seawater in the cold seawater pit 41, i.e., a portion of the cold seawater discharged from the ORV 1, to the ORV 1 branches off from the above-mentioned cold seawater supply line 402. The circulation line 401 branches off from the cold seawater supply line 402 at a position upstream of the above-mentioned on-off valve 433, and its downstream end merges with the ORV seawater supply line 301. The ORV seawater supply line 301 corresponds to the seawater supply line in this embodiment.

[0024] The resupply flow rate (circulation flow rate) of cold seawater to ORV1 is adjusted using a temperature detection unit 422 and a flow rate control valve 421 provided in the cold seawater pit 41 so that the temperature of the cold seawater in the cold seawater pit 41 becomes a preset target temperature (e.g., 15°C). The target temperature of the cold seawater is set to the temperature of cold seawater required by the cold energy utilization facility 5. In addition, an opening / closing valve 423 is provided in the circulation line 401, and the resupply of cold seawater to ORV1 can be started or stopped.

[0025] According to the configuration described above, by resupplying cold seawater to ORV1 via circulation line 401, the temperature of the seawater supplied to ORV1 is reduced (e.g., 18°C) compared to the conventional LNG vaporization equipment described using Figure 1. At this time, from the viewpoint of vaporization of LNG in ORV1, it is sufficient that the supply flow rate of seawater to ORV1, i.e., the total flow rate of the supply flow rate of seawater supplied via ORV seawater supply line 301 and the circulation flow rate of cold seawater supplied via circulation line 401, is secured so that the amount of heat required to vaporize the LNG to be supplied to the consumer is secured.

[0026] The operation of the LNG liquefaction facility having the above-described configuration will now be described. As in conventional LNG liquefaction facilities, in the ORV 1, seawater supplied via the ORV seawater supply line 301 is caused to flow down along the outer surface of the panel 11, and the LNG is vaporized to obtain fuel gas. A portion of the cold seawater whose temperature has been reduced by heat exchange with the LNG is received in the cold seawater pit 41 via the cold seawater pit line 302b. The remaining cold seawater is discharged toward the water outlet via the ORV discharge line 302a.

[0027] Of the cold seawater that flows into the cold seawater pit 41, the portion to be supplied to the cold heat utilization facility 5 is supplied to the cold heat utilization facility 5 via the cold seawater supply line 402 while the flow rate is adjusted according to the consumption amount. On the other hand, the circulation flow rate of the cold seawater resupplied to the ORV1 via the circulation line 401 is adjusted according to the temperature of the cold seawater in the cold seawater pit 41. That is, an operation control range is set centered on the target temperature of the cold seawater, and when the temperature of the cold seawater in the cold seawater pit 41 exceeds the upper limit of the operation control range, the circulation flow rate is increased and the temperature of the seawater supplied to the ORV1 is reduced. When the temperature of the cold seawater in the cold seawater pit 41 falls below the lower limit of the operation control range, the circulation flow rate is reduced and the temperature of the seawater supplied to the ORV1 is increased. As a result, cold seawater at a stable temperature within the operation control range can be supplied to the cold energy utilization facility 5.

[0028] The flow rate of cold seawater flowing into the cold seawater pit 41 via the cold seawater pit line 302b is adjusted so as to be balanced with the total flow rate of the supply flow rate to the cold energy utilization facility 5 and the circulation flow rate to the ORV 1. In addition, when the supply of cold seawater to the cold energy utilization equipment 5 is stopped, the opening / closing valves 433, 423 are closed to stop the discharge and circulation of the cold seawater, and the entire amount of seawater discharged from the ORV 1 is discharged to the outside via the ORV discharge line 302a.

[0029] In the LNG vaporization facility shown in Fig. 2, the temperature of the cold seawater discharged to the outside through the ORV discharge line 302a also drops in response to the temperature of the cold seawater supplied to the cold energy utilization facility 5. However, in this LNG vaporization facility, a portion of the cold seawater is re-supplied to the inlet side of the ORV 1. For this reason, the flow rate of cold seawater discharged outside the cold seawater circulation system including the ORV 1 and the cold seawater pit 41 (i.e., the flow rate of seawater newly supplied from the upstream side of the ORV seawater supply line 301) is significantly smaller than that of the conventional LNG vaporization facility described using Fig. 1.

[0030] The inventors have discovered that in the embodiment shown in Figure 2, the flow rate of cold seawater discharged outside the circulation system can be reduced by approximately 20 to 50 percent compared to the flow rate of seawater discharged from the ORV discharge line 302 in the conventional LNG vaporization equipment shown in Figure 1. Furthermore, because a portion of the cold seawater discharged outside the circulation system is supplied toward the cold energy utilization facility 5, the flow rate of the cold seawater discharged through the ORV discharge line 302a is even smaller. Therefore, even if the temperature of the cold seawater discharged through the ORV discharge line 302a drops to 15°C, the total discharge amount of cold seawater is small, and the impact on the environment can be kept small.

[0031] The LNG vaporization facility according to this embodiment has the following advantages: Since the facility is provided with a circulation line for resupplying to the ORV 1 a portion of the cold seawater whose temperature has been reduced by heat exchange for vaporizing the liquefied fuel in the ORV 1, the temperature of the cold seawater supplied to the cold energy utilization facility 5 can be adjusted to a desired temperature. In addition, by re-supplying cold seawater to the ORV 1, the flow rate of cold seawater discharged to the outside can be reduced, thereby reducing the impact of cold seawater on the environment.

[0032] Next, variations of the LNG vaporization equipment according to the embodiment will be described with reference to FIGS. 3 shows an example in which a cold seawater supply line pump 44b for the cold seawater supply line 402 and a circulation line pump 44a for the circulation line 401 are independently provided for the cold seawater pit 41. This configuration increases the degree of freedom in adjusting the supply flow rate of cold seawater to the cold energy utilization facility 5 and the circulation flow rate of cold seawater to the ORV 1.

[0033] 3 also shows an example in which an uncooled seawater supply line 403 is provided for supplying a portion of the uncooled seawater discharged from the flow rate control valve 431 toward the cold energy utilization facility 5. The uncooled seawater supply line 403 branches off from the ORV seawater supply line 301 and is connected to the cold energy utilization facility 5, and supplies seawater that is relatively warmer than the cold seawater. The supply flow rate of the seawater is adjusted using a flow rate detection unit 452 and a flow rate control valve 451 provided in the uncooled seawater supply line 403.

[0034] With the above-mentioned configuration, during a period when the temperature of seawater taken in at the intake pump 31 side is high (for example, in summer), cold seawater is supplied to the cold energy utilization facility 5 via the cold seawater supply line 402. During a period when the temperature of the taken in seawater is low (for example, in winter), relatively warm seawater discharged from the flow rate control valve 431 can be supplied via the uncooled seawater supply line 403 instead of or in parallel with the supply of cold seawater from the cold seawater supply line 402.

[0035] Next, FIG. 4 shows a pit circulation line 401 instead of the piping shown in FIG. 41a , 41b This shows an example of a configuration in which cold seawater is circulated using a In the LNG vaporization facility shown in Fig. 4, an ORV seawater supply pit 41b is interposed between the ORV seawater supply lines 301a and 301b, into which seawater flowing through the upstream ORV seawater supply line 301a flows. The ORV seawater supply pit 41b is provided adjacent to a cold seawater pit 41a, through a partition wall 411, into which the entire amount of cold seawater discharged from the ORV 1 through a cold seawater pit line 302b flows. A pit drainage line 302c, through which the cold seawater is discharged toward a discharge port, is connected to the cold seawater pit 41a.

[0036] The partition wall 411 is configured to have a height that allows cold seawater that cannot be contained in the cold seawater pit 41a to overflow toward the ORV seawater supply pit 41b through the upper end of the partition wall 411. In other words, the upper end surface of the partition wall 411, which is the area where cold seawater flows from the cold seawater pit 41a to the ORV seawater supply pit 41b, forms a circulation line through which cold seawater flows to be resupplied to the ORV 1.

[0037] An ORV supply pump 33 is provided in the ORV seawater supply pit 41b, and seawater is supplied to the ORV 1 via the ORV seawater supply line 301. A flow rate control valve 321a is provided in the ORV seawater supply line 301a, which supplies seawater from the ORV seawater supply line 301a to the ORV seawater supply pit 41b. The flow rate control valve 321a increases or decreases the flow rate of seawater flowing into the cold seawater pit 41a based on a temperature detection result from a temperature detection unit 323 that detects the seawater temperature in the ORV seawater supply pit 41b so that the temperature of the seawater in the ORV seawater supply pit 41b approaches a target temperature.

[0038] That is, when the temperature of the cold seawater flowing from the cold seawater pit 41a to the ORV seawater supply pit 41b rises and the temperature of the seawater in the ORV seawater supply pit 41b exceeds the upper limit of the operation management range set around the target temperature, the opening of the flow control valve 321a is increased to increase the flow rate of the seawater received. In accordance with this, the flow rate of the seawater supplied to the ORV 1 by the ORV supply pump 33 is also increased.

[0039] This operation increases the flow rate of cold seawater discharged from the ORV 1, and increases the amount of cold seawater circulating from the cold seawater pit 41a to the ORV seawater supply pit 41b. As a result, the temperature of the cold seawater flowing into the cold seawater pit 41a decreases, and the temperature of the seawater in the ORV seawater supply pit 41b also approaches the target temperature. Note that the amount of seawater in the ORV seawater supply pit 41b and the cold seawater pit 41a is kept constant by adjusting the amount of cold seawater discharged via the pit drainage line 302c, for example.

[0040] On the other hand, when the temperature of the cold seawater flowing from the cold seawater pit 41a to the ORV seawater supply pit 41b falls below the lower limit of the operation control range due to a decrease in the temperature of the seawater in the ORV seawater supply pit 41b, the opening of the flow control valve 321a is reduced to reduce the flow rate of the seawater received. In accordance with this, the flow rate of seawater supplied to the ORV 1 by the ORV supply pump 33 is also reduced.

[0041] This operation reduces the flow rate of cold seawater discharged from the ORV 1, and reduces the amount of cold seawater circulating from the cold seawater pit 41a to the ORV seawater supply pit 41b. As a result, the temperature of the cold seawater flowing into the cold seawater pit 41a drops, and the temperature of the seawater in the ORV seawater supply pit 41b also approaches the target temperature. In this case, too, the amount of seawater in the ORV seawater supply pit 41b and the cold seawater pit 41a is kept constant by adjusting the amount of cold seawater discharged via the pit drainage line 302c, for example.

[0042] 5 shows an example in which pumps 44a, 44b for sending cold seawater to a cold seawater supply line 402 and a circulation line 401 are provided for an ORV pit 12 provided on an ORV 1, instead of the cold seawater pit 41 shown in FIGS. 2 and 3. The ORV pit 12 serves to receive seawater after it flows along the outer surface of a panel 11 that performs heat exchange between LNG and seawater, and is provided on the ORV 1.

[0043] 5, a circulation line 401 for resupplying cold seawater in the ORV pit 12 to the ORV 1, and a pit drainage line 302c for discharging cold seawater toward the discharge port are connected to the circulation line pump 44a. On the other hand, cold seawater is supplied to the cold heat utilization facility 5 via a cold seawater supply line 402 using the cold seawater supply line pump 44b, similar to the LNG vaporization facility shown in FIG.

[0044] The LNG vaporization equipment according to each embodiment described above with reference to Figs. 2 to 5 may be used as hydrogen vaporization equipment that vaporizes liquefied hydrogen, which is a liquid fuel. In addition, the cold energy utilization facility to which cold seawater is supplied from the fuel vaporization facility of this example is tank For example, cold seawater may be supplied to coolers in chemical plants, oil refineries, etc. [Explanation of symbols]

[0045] 1 ORV 301, 301a, 301b Seawater Supply Line 401 Circulation Line 402 Cold Seawater Supply Line 5 Cooling and heat utilization equipment

Claims

1. A fuel vaporization system for vaporizing liquefied fuel, comprising: an open rack vaporizer that vaporizes the liquefied fuel by flowing seawater along outer surfaces of a plurality of heat transfer tubes to which the liquefied fuel is supplied; a seawater supply line for supplying seawater to the open rack vaporizer; a cold seawater supply line that supplies the cold seawater used for vaporizing the liquefied fuel in the open rack vaporizer and whose temperature has been reduced by heat exchange with the liquefied fuel to a cold energy utilization facility that utilizes the cold energy of the cold seawater; a circulation line for re-supplying a portion of the cold seawater discharged from the open rack vaporizer to the open rack vaporizer to reduce the temperature of the cold seawater to a preset temperature; a cold seawater pit for receiving the cold seawater discharged from the open rack vaporizer, the cold seawater supply line supplies the cold seawater in the cold seawater pit to the cold heat utilization facility, and the circulation line re-supplies the cold seawater in the cold seawater pit to the open rack vaporizer; a seawater supply pit is provided in the seawater supply line, into which seawater flowing through the seawater supply line flows, and which is provided adjacent to the cold seawater pit via a partition wall and configured to receive the cold seawater overflowing from an upper end of the partition wall, and the upper end surface of the partition wall, which is an area into which the cold seawater flows from the cold seawater pit to the seawater supply pit, constitutes the circulation line; by increasing or decreasing the flow rate of the seawater flowing into the seawater supply pit, the flow rate of cold seawater resupplied from the cold seawater pit via the seawater supply pit to the open rack vaporizer is increased or decreased, thereby adjusting the temperature of the cold seawater.

2. The fuel vaporization equipment according to claim 1, characterized in that the cold energy utilization equipment is an aquaculture tank that uses the cold energy of the cold seawater to regulate the temperature of water for cultivating seafood, or a plant factory that uses the cold energy to regulate the temperature of at least one of the plant growth atmosphere, growth soil, or culture water.

3. 2. The fuel vaporization system according to claim 1, wherein the liquefied fuel is liquefied natural gas or liquefied hydrogen.

4. 2. The fuel vaporization facility according to claim 1, further comprising an uncooled seawater supply line for supplying seawater that has not been cooled in the open rack vaporizer to the cold energy utilization facility.

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