Installation method for thermal energy storage system

Abstract

To reduce equipment cost and operation costs in an existing facility while improving the operation rate of the existing facility.SOLUTION: A construction method of the invention consists of: a liquid discharge step in which the fossil fuel is drained and emptied from a tank (40) in which the fossil fuel (F) was stored; a heat insulation treatment step in which a heat insulation layer (46) is provided on the inner surface side of the tanks, at least one tank is a high-temperature heat storage tank (51) for storing high-temperature heat storage material (HS) and at least one other tank is a low-temperature heat storage tank (52) for storing low-temperature heat storage material; a heat exchanger installation step in which a heat exchanger (54) in which the heat storage material flows between the high-temperature heat storage tank and the low-temperature heat storage tank is installed; and a line connection step to connect the heat exchanger to a low-temperature section line (26) and a high-temperature section line (27) through which a circulating heat medium flows between a boiler (20) and a load section (30).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for constructing a thermal storage energy utilization system. law Regarding. [Background technology]

[0002] Large tanks for storing liquids are used in various facilities and sites, and for example, in facilities that use large amounts of fossil fuels, such as oil refineries, multiple tanks for storing fossil fuels are installed (see Patent Document 1). Furthermore, in large facilities with such tanks, in addition to using commercial electricity, private power generation equipment is often installed, and the facility is operated using both electricity from the private power generation equipment and commercial electricity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-339400 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the introduction of power generation systems that utilize renewable energy sources such as solar and wind power has been expanding. As a result, facilities that use fossil fuels tend to be smaller in scale, which results in tanks being unused for longer periods of time or many tanks going unused, resulting in a problem of a decline in the operating rate of the facilities.

[0005] Furthermore, when using renewable energy, it is necessary to secure facilities that can supply regulated power. Meanwhile, under the global demand for a decarbonized society, existing large-scale thermal power plants are being forced to downsize or be phased out. Therefore, it is necessary to ensure the ability to supply regulated power while downsizing existing large-scale thermal power plants. For this reason, there is a demand to reduce facility and operating costs at facilities with existing power generation facilities so that they can promote the supply of power to outside the facilities, etc.

[0006] The present invention has been made in view of the above points, and provides a method for constructing a thermal storage energy utilization system that can reduce the equipment costs and operation costs of existing facilities while improving the availability of existing facilities. law One of the aims is to provide [Means for solving the problem]

[0007] A construction method for a thermal storage energy conversion system according to one embodiment of the present invention includes a liquid discharge step of discharging and emptying the liquid from at least two tanks that had stored the liquid; an insulation treatment step of providing an insulating layer on the inner surface of the tanks, making at least one of the tanks a high-temperature heat storage tank that stores high-temperature heat storage material and at least one other tank a low-temperature heat storage tank that stores heat storage material that is lower in temperature than the high-temperature heat storage material; a heat exchanger installation step of installing a heat exchanger between the high-temperature heat storage tank and the low-temperature heat storage tank, through which the heat storage material flows; and a line connection step of connecting the heat exchanger to a line through which the heat medium circulates between a high-temperature heat medium supply unit that heats the heat medium and a load unit that produces output using the high-temperature heat medium. [Effects of the Invention]

[0009] According to the present invention, an insulating layer is provided to convert an existing tank into a heat storage tank, which prevents the tank from going unused, improving the availability rate of the facility and reducing construction costs such as capital investment for a facility that uses a heat storage tank. Furthermore, by introducing a heat storage tank into the system, the thermal energy stored in the high-temperature heat storage tank can be used when needed to respond to changes in output from the load, enabling efficient energy output and reducing operating costs. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic configuration diagram of a system before a construction method according to an embodiment is carried out. [Figure 2] Figure 2A is an explanatory cross-sectional view showing the tank before the construction method of the embodiment is carried out, Figure 2B is an explanatory cross-sectional view showing the tank at an intermediate stage of the insulation treatment step, and Figure 2C is an explanatory cross-sectional view showing the tank after the insulation treatment step has been carried out. [Figure 3] FIG. 2 is a schematic diagram similar to FIG. 1, illustrating a state after a heat insulating treatment step has been performed. [Figure 4] FIG. 2 is a schematic diagram similar to FIG. 1, illustrating a state after a heat exchanger installation step has been performed. [Figure 5] FIG. 2 is a schematic diagram similar to FIG. 1, illustrating a state after a line connection step has been performed. [Figure 6] FIG. 2 is a schematic diagram similar to FIG. 1, illustrating a state after a line connection step has been performed. [Figure 7] FIG. 7A is a graph showing the change over time in the thermal output of the boiler and the output of the load section, and FIG. 7B is a graph showing the change over time in the amount of heat storage material stored in each heat storage tank. [Figure 8] FIG. 6 is a schematic diagram similar to FIG. 5, illustrating a state after the replacement step has been performed. DETAILED DESCRIPTION OF THE INVENTION

[0011] A construction method for a thermal storage energy utilization system according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. First, the system configuration before the construction method according to the embodiment is implemented will be described with reference to FIG. 1. FIG. 1 is a schematic diagram of the system before the construction method according to the embodiment is implemented. The facility shown in FIG. 1 is equipped with a power generation system 10 and two (or more) tanks 40. An example of the facility shown in FIG. 1 is an oil refinery that operates the power generation system 10 as a private power generation facility and stores fossil fuels in the tanks 40.

[0012] In this embodiment, the power generation system 10 is a thermal power generation system. The power generation system 10 includes a boiler (high-temperature heat medium supply unit) 20 that heats water / steam (heat medium) ST, and a load unit 30 that generates output using the high-temperature water / steam ST.

[0013] The housing 22 of the boiler 20 houses heat transfer tubes 25 that are heated by a heat source 23. The heat source 23 generates heat from the combustion of fuel for thermal power generation, and the fuel may be fossil fuels such as coal, oil, or natural gas, various biomass fuels, hydrogen fuel, ammonia fuel, or the like.

[0014] The heat transfer tubes 25 receive the combustion heat of the heat source 23 and heat the low-temperature water / steam ST that flows in from the low-temperature section line 26 at the lower end, converting it into high-temperature water / steam ST and causing it to flow out from the high-temperature section line 27 at the upper end. The high-temperature water / steam ST flows into the steam turbine 31 in the load section 30 via the high-temperature section line 27.

[0015] The load section 30 constitutes a steam turbine generator and includes a steam turbine 31 to which high-pressure, high-temperature water and steam ST is supplied, an output shaft 32, and a generator G that generates electricity by rotation of the output shaft 32. A condenser 33 is provided below the steam turbine 31 to recover the water and steam ST that has absorbed thermal energy and become low in temperature. The low-temperature water and steam ST in the condenser 33 flows into the heat transfer tubes 25 in the boiler 20 via the low-temperature section line 26 by driving a circulation pump 35. Although not shown, a drain facility, a heat exchanger, etc. may be provided in the path of the low-temperature section line 26.

[0016] As described above, by driving the circulation pump 35, the water / steam ST circulates between the boiler 20 and the load section 30 via the low-temperature section line 26 and the high-temperature section line 27, changing its temperature from low temperature to high temperature to low temperature, etc., repeatedly releasing and absorbing energy.

[0017] A plurality of tanks 40 are installed in the facility shown in Fig. 1, but here, a case where two of them are used will be described. Before carrying out the construction method according to the embodiment, fossil fuel (liquid) F is stored in the tank 40 under atmospheric pressure.

[0018] FIG. 2A is an explanatory cross-sectional view showing a tank before the construction method for a thermal storage energy utilization system according to an embodiment is carried out. FIG. 2A illustrates a tank 40, which has a structure generally used in various facilities, as an example. The tank 40 includes a cylindrical peripheral wall 41 and a bottom wall 42 provided below the peripheral wall 41, and a storage space for fossil fuel F is formed inside. A floating plate 44 is provided above the liquid surface of the fossil fuel F stored in the storage space, and a ladder 45 is provided between the upper surface of the floating plate 44 and the upper end of the peripheral wall 41. The peripheral wall 41 and the bottom wall 42 are made of structural steel plate, and an example of the structural steel plate is a general carbon steel (e.g., SM490A) which has little loss of strength.

[0019] Next, the construction method according to this embodiment will be described below. The construction method according to this embodiment includes a liquid discharge step, a heat insulation step, a heat exchanger installation step, and a line connection step.

[0020] The facility shown in Fig. 1 is an operating facility before the construction method according to this embodiment is carried out. In the liquid discharge step, the fossil fuel F stored in at least two tanks 40 is discharged and emptied. Furthermore, if a floating plate 44 or ladder 45 as shown in Fig. 2A is present, these are removed. Note that if the tanks 40 are emptied during operation of the facility and are in an unused state, the liquid discharge step is the work or process of emptying them immediately before they become unused.

[0021] After the liquid discharge step is performed, the heat insulating step is performed. Figure 2B is an explanatory cross-sectional view showing the tank during the heat insulating step. Figure 2C is an explanatory cross-sectional view showing the tank after the heat insulating step has been performed.

[0022] 2B, in the insulation treatment step, a heat insulating layer 46 is provided on the inner surface of each of the peripheral wall 41 and the bottom wall 42 of the tank 40. Next, the inner surface of the heat insulating layer 46 is covered with a liner 47. The functions, materials, etc. of the heat insulating layer 46 and the liner 47 will be described later.

[0023] Furthermore, in the heat insulation treatment step, as shown in Fig. 2C, a roof 48 is installed so as to cover the upper part of the peripheral wall 41 of the tank 40. The shape of the roof 48 is not particularly limited as long as it has a predetermined degree of occlusion within the tank 40. While Fig. 2C shows an example of a dome-shaped roof 48, various modifications are possible, such as forming the roof 48 in a cone shape or a flat shape with a water gradient.

[0024] An insulating layer 46 is also provided on the inner surface of the roof 48. Note that the formation of a liner 47 is omitted on the roof 48. Fig. 3 is a schematic configuration diagram similar to Fig. 1, showing the state after the insulation treatment step has been carried out. The two tanks 40 shown in Fig. 3 are provided with an insulating layer 46, a liner 47, and a roof 48, and the tank 40 shown on the upper side in Fig. 3 is a high-temperature heat storage tank 51, and the tank 40 shown on the lower side in the same figure is a low-temperature heat storage tank 52. Each of the heat storage tanks 51, 52 is used to store a heat storage material HS, which will be described later.

[0025] After the heat insulation treatment step is performed, a heat exchanger installation step is performed. Fig. 4 is a schematic configuration diagram similar to Fig. 1, showing a state after the heat exchanger installation step is performed. As shown in Fig. 4, in the heat exchanger installation step, a heat exchanger 54 is installed between the high-temperature heat storage tank 51 and the low-temperature heat storage tank 52, through which the heat storage material HS flows. Furthermore, before and after the installation of the heat exchanger 54, a high-temperature heat storage tank piping 61 and a low-temperature heat storage tank piping 62, through which the heat storage material HS flows, are installed. The heat exchanger 54, the high-temperature heat storage tank 51, the low-temperature heat storage tank 52, and the piping 61, 62 configure a heat storage system 50.

[0026] Here, the heat exchanger 54 can be exemplified by a configuration including a heat transfer tube 55 having a shape suitable for heat exchange (for example, a coil shape), and a container 56 that accommodates the heat transfer tube 55 and the heat storage material HS. After the line connection step, water / steam ST flows through the heat transfer tube 55.

[0027] The high-temperature heat storage tank piping 61 is installed to connect the high-temperature heat storage tank 51 to the upper part of the container 56 of the heat exchanger 54. The low-temperature heat storage tank piping 62 is installed to connect the low-temperature heat storage tank 52 to the lower part of the container 56 of the heat exchanger 54.

[0028] The high-temperature heat storage tank piping 61 branches into a supply pipe 61a and a recovery pipe 61b and is installed so that there are two connection points to the high-temperature heat storage tank 51. The low-temperature heat storage tank piping 62 branches into a supply pipe 62a and a recovery pipe 62b and is installed so that there are two connection points to the low-temperature heat storage tank 52. The supply pipes 61a, 62a are used when supplying the heat storage material HS to the container 56 of the heat exchanger 54, and the recovery pipes 61b, 62b are used when recovering the heat storage material HS from the container 56 of the heat exchanger 54.

[0029] A pump 61c is provided in the supply pipe 61a of the high-temperature heat storage tank piping 61 to send the heat storage material HS from the high-temperature heat storage tank 51 to the heat exchanger 54. A valve 61d is provided in the recovery pipe 61b of the high-temperature heat storage tank piping 61 to block and allow the flow of the heat storage material HS.

[0030] A pump 62c is provided in the supply pipe 62a of the low-temperature heat storage tank piping 62 to send the heat storage material HS from the low-temperature heat storage tank 52 to the heat exchanger 54. A valve 62d is provided in the recovery pipe 62b of the low-temperature heat storage tank piping 62 to block and allow the flow of the heat storage material HS.

[0031] After the heat exchanger 54 is installed, in a heat exchanger installation step or a line connection step, the heat storage material HS is stored in the high-temperature heat storage tank 51 and the low-temperature heat storage tank 52. Here, for example, a chemically inactive molten salt with high fluidity is used as the heat storage material HS. The heat storage material HS stored in the low-temperature heat storage tank 52 is set to a lower temperature than the heat storage material HS stored in the high-temperature heat storage tank 51; for example, the heat storage material HS stored in the high-temperature heat storage tank 51 is set to about 600°C, and the heat storage material HS stored in the low-temperature heat storage tank 52 is set to about 300°C.

[0032] After the heat exchanger installation step is performed, the line connection step is performed. Figures 5 and 6 are schematic configuration diagrams similar to Figure 1, showing the state after the line connection step is performed. Figure 5 shows the state in which the heat storage system 50 is storing heat, and Figure 6 shows the state in which the heat storage system 50 is releasing heat. As shown in Figure 5, the line connection step connects the heat exchanger 54 to the low temperature section line 26 and the high temperature section line 27 via the low temperature connection line 64 and the high temperature connection line 65.

[0033] The low-temperature connection line 64 is installed so as to branch off from the middle of the low-temperature section line 26, and is connected to communicate with one end (lower end) of the heat transfer tube 55 of the heat exchanger 54. The high-temperature connection line 65 is installed so as to branch off from the middle of the high-temperature section line 27, and is connected to communicate with the other end (upper end) of the heat transfer tube 55 of the heat exchanger 54. As shown in Figure 6, low-temperature water / steam ST flows in and out between the low-temperature section line 26 and the low-temperature connection line 64, and high-temperature water / steam ST flows in and out between the high-temperature section line 27 and the high-temperature connection line 65.

[0034] By connecting the low temperature connection line 64 and the high temperature connection line 65 as described above, the construction of the thermal storage energy utilization system 1 of this embodiment is completed.

[0035] The operation of the pumps 35, 61c, 62c and valves 61d, 62d described above is controlled by a control unit 70. The control unit 70 can be exemplified by a programmable logic controller (PLC) or a personal computer (PC) as a device having a storage unit and a communication unit. The control unit 70 is made up of a central processing unit (CPU) and the like, and controls the entire thermal storage energy utilization system 1 by controlling each unit of the system.

[0036] Next, an output adjustment method in the thermal storage energy utilization system 1 of this embodiment will be described with reference to Fig. 7 in addition to Fig. 5 and Fig. 6. Fig. 7A is a graph showing the time change in the thermal output of the boiler and the output of the load section, and Fig. 7B is a graph showing the time change in the amount of heat storage material stored in each heat storage tank.

[0037] In operation of the thermal storage energy utilization system 1, the boiler 20 is operated at rated power so that the thermal output is constant throughout the day, as shown in Fig. 7A. It is also assumed that the required output (power generation amount) of the load section 30 is relatively lower during the daytime (6:00 to 18:00) than at nighttime (18:00 to 6:00). Note that the output change of the load section 30 shown in Fig. 7A is merely an example, and it is also possible to reverse the daytime and nighttime output, or to gradually increase or decrease the output.

[0038] Under the above conditions, the control unit 70 drives the circulation pump 35 to control the amount of water / steam ST flowing from the load unit 30 through the low-temperature section line 26 into the boiler 20 to a predetermined amount. Here, during the daytime when the required output of the load unit 30 is low, thermal energy is stored in the thermal storage system 50 while reducing the output of the load unit 30 in accordance with the daytime output, which is lower than at night. As shown in FIG. 5 , the stored thermal energy is obtained by passing high-temperature water / steam ST from the high-temperature section line 27 through the high-temperature connection line 65 to the heat transfer tube 55 of the heat exchanger 54, and exchanging heat with the thermal storage material HS flowing inside the container 56. At this time, the control unit 70 controls the driving of each pump 61c, 62c and the opening and closing of each valve 61d, 62d as follows.

[0039] In the daytime, the control unit 70 drives the pump 62c of the low-temperature heat storage tank piping 62 to send the heat storage material HS from the low-temperature heat storage tank 52 through the supply pipe 62a to the container 56 of the heat exchanger 54. Furthermore, the valve 61d of the high-temperature heat storage tank piping 61 is opened to allow the heat storage material HS in the container 56 to flow into the high-temperature heat storage tank 51 through the recovery pipe 61b. Note that the valve 62d of the low-temperature heat storage tank piping 62 is closed, and the pump 61c of the high-temperature heat storage tank piping 61 is controlled to stop driving.

[0040] 7B, the amount of the heat storage material HS stored in the high-temperature heat storage tank 51 gradually increases, and the amount of the heat storage material HS stored in the low-temperature heat storage tank 52 gradually decreases. Therefore, the total heat storage energy of the heat storage system 50 increases.

[0041] Furthermore, the water / steam ST from which thermal energy has been absorbed in the heat exchanger 54 flows into the low-temperature section line 26 via the low-temperature connection line 64. In the power generation system 10, when the output of the boiler 20 is constant, the output of the load section 30 decreases in response to the increased thermal energy stored in the thermal storage system 50.

[0042] On the other hand, at night when the required output of the load section 30 is greater, operation is performed to increase the output using the thermal energy stored in the heat storage system 50 in accordance with the nighttime output that is greater than that during the day. In such operation, as shown in Fig. 6, low-temperature water / steam ST passes from the low-temperature section line 26 through the low-temperature connection line 64 to the heat transfer tube 55 of the heat exchanger 54, and exchanges heat with the heat storage material HS flowing inside the container 56. At this time, the control section 70 controls the driving of each of the pumps 61c, 62c and the opening and closing of each of the valves 61d, 62d as follows.

[0043] The control unit 70 controls at night by driving the pump 61c of the high-temperature heat storage tank piping 61 to send the heat storage material HS from the high-temperature heat storage tank 51 to the container 56 of the heat exchanger 54 via the supply pipe 61a. Furthermore, the valve 62d of the low-temperature heat storage tank piping 62 is opened to allow the heat storage material HS in the container 56 to flow into the low-temperature heat storage tank 52 through the recovery pipe 62b. Note that the valve 61d of the high-temperature heat storage tank piping 61 is closed, and the pump 62c of the low-temperature heat storage tank piping 62 is controlled to stop driving.

[0044] 7B, the amount of the heat storage material HS stored in the high-temperature heat storage tank 51 gradually decreases, and the amount of the heat storage material HS stored in the low-temperature heat storage tank 52 gradually increases. Therefore, the total heat storage energy of the heat storage system 50 decreases.

[0045] Furthermore, the water / steam ST that has absorbed thermal energy in the heat exchanger 54 flows into the high-temperature section line 27 via the high-temperature connection line 65, and releases the energy at the load section 30. Therefore, in the power generation system 10, when the output of the boiler 20 is constant, the output of the load section 30 increases in accordance with the stored thermal energy released from the thermal storage system 50.

[0046] As described above, according to this embodiment, the existing tank 40 is provided with the insulating layer 46 and is repurposed as the high-temperature heat storage tank 51 and the low-temperature heat storage tank 52 that constitute the heat storage system 50. This makes it possible to prevent the existing tank 40 from going unused due to a reduction in the scale of the facility, etc., and improves the availability rate of the facility. Furthermore, since the existing tank 40 can be utilized, it is possible to reduce capital investment and construction costs compared to when the heat storage tanks 51 and 52 are newly constructed.

[0047] Furthermore, by controlling the release of the amount of energy stored in the heat storage system 50, the output of the load section 30 can be changed according to the required load. This allows the boiler 20 and the load section 30 to output efficiently, reducing operating costs in a facility that has an existing power generation system 10. In this way, not only construction costs but also operating costs can be reduced, making it possible to promote the facility to be able to supply power outside the facility, etc., and ultimately increasing the number of facilities that can supply regulated power and promoting the use of renewable energy.

[0048] Here, the heat insulating layer 46 and the liner 47 formed by the heat storage tanks 51 and 52 will be described below.

[0049] The heat insulating layer 46 has a heat insulating function and a supporting function of transmitting the internal pressure caused by the heat storage material HS made of molten salt to the peripheral wall 41 and the bottom wall 42.

[0050] The heat insulating function is to maintain a constant surface temperature of the peripheral wall 41, bottom wall 42, and foundation slab supporting the thermal storage tanks 51, 52, and to keep the heat storage material HS warm. Maintaining a constant surface temperature of the peripheral wall 41, bottom wall 42, and foundation slab prevents a decrease in their strength. This allows the required thickness of the structural steel plates for the peripheral wall 41 and bottom wall 42 to be rationalized.

[0051] The support function is to transmit the internal pressure caused by the heat storage material HS to the peripheral wall 41 and bottom wall 42 via the liner 47 and the insulating layer 46. If the liner 47, the insulating layer 46, and the peripheral wall 41 or the bottom wall 42 are in close contact with each other, the internal pressure can be transmitted as an out-of-plane force. The insulating layer 46 has sufficient compressive strength against internal pressure and is made of a material with sufficient rigidity so that the liner 47 will not be damaged by deformation.

[0052] The insulating layer 46 is shaped like a vertically long strip that is curved along the cylindrical peripheral wall 41, and is arranged to prevent cracks due to internal pressure. The insulating layer 46 is supported by the peripheral wall 41 or the bottom wall 42, and it is preferable to minimize the number of supporting points by using as large a plate shape as possible to minimize heat paths.

[0053] By using, for example, a calcium silicate-based heat insulating board (heat insulating material) for the heat insulating layer 46, it is possible to achieve both the heat insulating function and the support function even at high temperatures.

[0054] The function of the liner 47 is to resist corrosion of the heat storage material (molten salt) HS and to ensure the liquid-tightness of the heat storage material HS. The liner 47 is a layer made of highly corrosion-resistant steel (for example, stainless steel such as SUS316).

[0055] In order to withstand corrosion of the heat storage material HS, the thickness of the liner 47 is set to a thickness that can withstand corrosion during its service life. In order to ensure the liquid-tightness of the heat storage material HS, the liner 47 is made a closed layer to prevent leakage.

[0056] Here, since the liner 47 is heated to a higher temperature than the insulating layer 46, the thermal strain of the liner 47 is greater than that of the insulating layer 46, and slack occurs in the liner 47. Due to this slack, no membrane force due to the internal pressure of the heat storage material HS occurs in the liner 47. For the above reasons, the liner 47 can be made to have the minimum thickness required to withstand corrosion, without considering the burden of stress.

[0057] The embodiments of the present invention are not limited to the above-described embodiments, and may be variously changed, substituted, or modified without departing from the spirit and scope of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0058] In the construction method of the above embodiment, after the line connection step is performed, a replacement step may be performed as shown in FIG. 8. FIG. 8 is a schematic configuration diagram similar to FIG. 5, showing the state after the replacement step is performed. In the replacement step, the boiler 20 (see FIG. 5) and the electrothermal converter 80 are replaced and installed, and the low-temperature section line 26 and the high-temperature section line 27 are connected to the electrothermal converter 80. The electrothermal converter 80 is composed of a heater or the like that is operated by a commercial power source supplied from outside the facility. Like the boiler 20, the electrothermal converter 80 heats the low-temperature water / steam ST that flows in from the low-temperature section line 26, converts it into high-temperature water / steam ST, and outputs it from the high-temperature section line 27.

[0059] By carrying out the replacement step, for example, in the future when a large number of renewable energy facilities are introduced, it is possible to increase the amount of energy stored in the heat storage material HS of the high-temperature heat storage tank 51 by the electrothermal converter 80 using daytime electricity. On the other hand, by controlling the release of the amount of energy stored in the heat storage material HS at night, it is possible to change the output of the load section 30 in accordance with the required load, and it becomes possible to make better use of the energy as regulating power.

[0060] The high-temperature heat medium supply unit can be modified in various ways, and may be configured, for example, as a heat recovery boiler that recovers exhaust heat from a gas turbine generator to heat the heat medium. In this configuration, the exhaust heat from the gas turbine generator is supplied via piping to heat transfer tubes in the heat recovery boiler to heat the water / steam ST, and thereafter the steam turbine generator of the load unit 30 can be driven by the same operation as in the above embodiment.

[0061] Furthermore, the facility to which the construction method of the above embodiment is applied is not limited to an oil refinery, but can be applied to various facilities as long as they are equipped with a tank similar to the tank 40 used in an oil refinery and a power generation system 10 similar to the above.

[0062] In addition, the existing tanks 40 in the facility only need to include at least one tank 40 that can be converted into a high-temperature heat storage tank 51 and at least one tank 40 that can be converted into a low-temperature heat storage tank 52, and if there are three or more tanks 40, there may be multiple high-temperature heat storage tanks 51 and multiple low-temperature heat storage tanks 52.

[0063] In the above embodiment, the high-temperature heat storage tank 51 and the low-temperature heat storage tank 52 are installed by repurposing the existing tank 40 in the facility, but this is not limited to this. The high-temperature heat storage tank 51 and the low-temperature heat storage tank 52 having the same structure as described above may be newly installed without using the existing tank 40.

[0064] In the above embodiment, water / steam ST is used as the heat medium, but a gas other than steam, such as helium gas, may also be used as the heat medium.

[0065] Furthermore, the heat exchanger 54 may have a configuration different from that using the heat transfer tube 55, as long as it can perform heat exchange in the same manner as in the above embodiment.

[0066] Furthermore, the load section 30 is not limited to a configuration using the steam turbine 31, and may be another heat utilization device capable of extracting thermal energy from the heat medium supplied from the high-temperature heat medium supply section.

[0067] Furthermore, the amount of water / steam ST delivered by driving the circulation pump 35 may be constant or may be varied as appropriate, but keeping it constant is advantageous in that control can be simplified.

[0068] Furthermore, the power generation system 10 only needs to be configured to include, at least in part, a high-temperature heat medium supply section such as a boiler 20 and a load section 30, and may be configured to include pumps and heat exchangers other than those described above. [Explanation of symbols]

[0069] 1: Thermal storage energy utilization system 10: Power generation system 20: Boiler (high-temperature heat transfer medium supply section) 23:Heat source 26: Low temperature line (line) 27: High temperature line (line) 30: Load section 40: Tank 41: Peripheral wall 42: Bottom wall 46: Heat insulating layer 47: Liner 48: Roof 51: High temperature heat storage tank 52: Low temperature heat storage tank 54:Heat exchanger 64: Low temperature connection line 65: High temperature connection line 80: Electrothermal conversion device F: Fossil fuel (liquid) HS: Heat storage material ST: Water / steam (heat medium)

Claims

1. a liquid draining step of draining and emptying the liquid from at least two tanks that have stored the liquid; a heat insulating treatment step of providing a heat insulating layer on the inner surface side of the tanks, making at least one of the tanks a high-temperature heat storage tank for storing a high-temperature heat storage material, and making at least one other of the tanks a low-temperature heat storage tank for storing a heat storage material that is lower in temperature than the high-temperature heat storage material; a heat exchanger installation step of installing a heat exchanger through which the heat storage material flows between the high-temperature heat storage tank and the low-temperature heat storage tank; a line connecting step of connecting the heat exchanger to a line through which the heat medium circulates between a high-temperature heat medium supply unit that heats a heat medium and a load unit that produces output using the high-temperature heat medium.

2. the high-temperature heat medium supply unit heats and supplies the heat medium using combustion heat of fuel for thermal power generation or exhaust heat from external equipment as a heat source; 2. The method for constructing a thermal storage energy utilization system according to claim 1, wherein after the line connection step is performed, an exchange step is performed in which an electrothermal conversion device capable of heating the heat medium using external power is replaced with the high-temperature heat medium supply unit.

3. 3. The method for constructing a thermal storage energy utilization system according to claim 1, wherein the high-temperature heat medium supply section and the load section constitute at least a part of a power generation system.

4. 3. The method for constructing a thermal storage energy utilization system according to claim 1, wherein the insulating step comprises installing a roof having an insulating layer on the inner surface of the tank on top of the tank.

5. 3. The method for constructing a thermal storage energy utilization system according to claim 1, wherein the insulating layer is covered with a liner in the insulating treatment step.

6. 3. The method for constructing a thermal storage energy utilization system according to claim 1, wherein the thermal storage material is molten salt.

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