Unutilized heat recovery facility and unutilized heat recovery method

Abstract

To provide an unutilized heat recovery facility and an unutilized heat recovery method capable of manufacturing a heat medium having a temperature suitable for each of parts requiring heat by using unutilized heat such as exhaust heat as a heat source, and capable of effectively utilizing the unutilized heat throughout a year.SOLUTION: A heat recovery facility 100 for recovering unutilized heat includes a first heat pump 1 for producing a first heat medium whose temperature is higher than that of the unutilized heat by using the unutilized heat as a heat source, and a second heat pump 2 for producing a second heat medium whose temperature is higher than that of the high-temperature first heat medium by using the high-temperature first heat medium produced by the first heat pump 1 as a heat source.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an unused heat recovery facility and an unused heat recovery method. [Background technology]

[0002] Steelworks generate by-product gases such as coke oven gas, blast furnace gas, and converter gas. These by-product gases are recovered and effectively used as fuel for heating furnaces, thermal power plants, steam boilers, etc. within the steelworks.

[0003] Furthermore, among these facilities, for example, in thermal power plants, a steam turbine is rotated by high-temperature, high-pressure steam generated in a steam boiler. A generator is connected to the steam turbine, which drives the generator to generate electricity. The steam that rotates the steam turbine is introduced into a condenser, where it is cooled and condensed by heat exchange with cooling water supplied to the condenser separately from the steam. In this way, the steam returns to saturated water, which is then supplied to the steam boiler again and vaporized. In this way, in the thermal power plant described above, water circulates between the steam boiler, steam turbine, and condenser.

[0004] On the other hand, the temperature of the cooling water supplied to the condenser increases as a result of heat exchange with the steam, and the heat used to warm the cooling water is discharged to the outside of the condenser as waste heat.

[0005] Steelworks also use various gases, including oxygen gas used in the decarburization blowing process in the steelmaking process. Among these gases, oxygen gas, nitrogen gas, and argon gas are produced by separating them from the atmosphere using a cryogenic separation system installed in the steelworks and then supplied to the respective locations where they are needed. The cryogenic separation system has an adsorber that adsorbs and removes water and carbon dioxide from the atmosphere. The adsorber removes water and carbon dioxide from the atmosphere before separating each gas from the atmosphere. Specifically, water and carbon dioxide are adsorbed in a solid state by the adsorber and removed. Therefore, once a certain amount of water and carbon dioxide is adsorbed in the adsorber, steam is supplied to the adsorber, and the water and carbon dioxide are vaporized by the steam and discharged from the adsorber. The adsorber is thus regenerated, and the regenerated adsorber adsorbs and removes water and carbon dioxide from the atmosphere. Note that a portion of the gases produced by the cryogenic separation system is stored in a liquefied state (sometimes referred to as liquefied gas). When each of the above gases is needed, the liquefied gas is vaporized using hot water or steam in the vaporizer, and the gas is supplied to the location where it is needed.

[0006] As an example of a method for effectively utilizing waste heat, a heat pump that recovers and utilizes heat from the waste heat of a condenser is described in Patent Document 1. The heat pump described in Patent Document 1 produces hot water using the waste heat from the condenser, i.e., hot wastewater, as a heat source. The heat pump described in Patent Document 1 uses the hot water produced in this way for heating in winter.

[0007] Patent Document 2 describes an example of a recovery method for recovering exhaust heat generated in a cryogenic separation device. In the method described in Patent Document 2, steam used to regenerate an adsorber in the cryogenic separation device is recovered and used as a heat source to produce hot water. The hot water is then used as a heat source to vaporize liquefied gas in an vaporizer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 4-198673 [Patent Document 2] Japanese Patent Application Publication No. 2019-196873 Summary of the Invention [Problem to be solved by the invention]

[0009] Because the hot water produced by the heat pump described in Patent Document 1 is for heating in the winter, there is a possibility that the use of the hot water will be limited or will be no use at all outside of the winter. Therefore, there is still room for improvement in the heat pump described in Patent Document 1 in terms of effectively utilizing waste heat throughout the year.

[0010] In the method described in Patent Document 2, the steam used to regenerate the adsorber is used as a heat source to produce hot water necessary for vaporizing the liquefied gas in the vaporizer. However, the steam is not generated except when the adsorption tower is being regenerated. Therefore, the steam alone may not be enough to ensure the heat required for vaporizing the liquefied gas in the vaporizer. Therefore, unless steam is supplied as a heat source from an external source, the vaporizer may not be able to produce a sufficient amount of hot water necessary for vaporizing the liquefied gas.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide unused heat recovery equipment and an unused heat recovery method that can use unused heat such as exhaust heat as a heat source to produce a heat medium at a temperature appropriate for each location where heat is needed, and that can effectively utilize the unused heat throughout the year. [Means for solving the problem]

[0012] The means for solving the above problems are as follows. [1] An unused heat recovery facility that recovers unused heat, the unused heat recovery facility having a first heat pump that uses the unused heat as a heat source to produce a first heat medium that is hotter than the unused heat, and a second heat pump that uses the high-temperature first heat medium produced by the first heat pump as a heat source to produce a second heat medium that is even hotter than the high-temperature first heat medium. [2] The unused heat recovery equipment according to [1], which has a tank disposed between the first heat pump and the second heat pump in the heat transfer direction and stores the high-temperature first heat medium produced by the first heat pump. [3] The unused heat recovery equipment according to [1] or [2], wherein the unused heat is hot wastewater from a steam turbine condenser. [4] An unused heat recovery facility according to any one of [1] to [3], having a first supply pipe for supplying a high-temperature first heat medium produced by the first heat pump to an evaporation device that evaporates liquefied gas. [5] An unused heat recovery facility according to any one of [1] to [4], which has a second supply pipe that supplies the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air. [6] A method for recovering unused heat, comprising: a first heating step of using the unused heat as a heat source to produce a first heat medium having a higher temperature than the unused heat; and a second heating step of using the high-temperature first heat medium produced in the first heating step as a heat source to produce a second heat medium having an even higher temperature than the high-temperature first heat medium. [Effects of the Invention]

[0013] In the present invention, by connecting two heat pumps in series, it is possible to produce a first heat medium having a higher temperature than the unused heat using the unused heat as a heat source, and a second heat medium having a higher temperature than the first heat medium using the first heat medium as a heat source. For example, hot water can be produced using the unused heat as a heat source, and steam can be produced using the hot water as a heat source. In the present invention, a heat medium having a temperature suitable for each location requiring heat can be produced. Therefore, according to the present invention, the first heat medium and the second heat medium having different temperatures can be supplied to each location requiring the heat of the first heat medium and the second heat medium. This also allows for effective use of unused heat throughout the year. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing an example of unused heat recovery equipment according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing an example of equipment to which the unused heat recovery equipment according to the present embodiment can be applied. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] An example of an embodiment of the present invention (hereinafter referred to as this embodiment) will be described below. FIG. 1 is a diagram showing an example of unused heat recovery equipment according to this embodiment. The unused heat recovery equipment 100 shown in FIG. 1 produces hot water using unused heat as a heat source, and also produces steam using the hot water as a heat source. Specifically, the unused heat recovery equipment 100 has two heat pumps 1 and 2, which are connected in series in the direction of heat transfer. The first heat pump 1 is located upstream of the second heat pump 2 in the direction of heat transfer. The first heat pump 1 is configured to heat low-temperature water using unused heat as a heat source, and to produce hot water that is at a temperature higher than the unused heat, as described above.

[0016] In the following description, low-temperature water is referred to as raw water, and water heated by unused heat is referred to as hot water. Examples of such water include distilled water, tap water, and industrial water. The raw water and hot water correspond to the first heat medium in this embodiment.

[0017] Examples of unused heat include waste heat from equipment and devices that generate heat during operation, waste heat generated by heating and cooling, waste heat generated in the manufacturing process or manufacturing facilities for various products, and waste heat generated due to the temperature difference between domestic wastewater or sewage and the atmosphere. In other words, unused heat includes heat that is not used and is discharged to the outside of the above-mentioned equipment and devices or manufacturing facilities. For example, cooling water (hereinafter referred to as heated wastewater) that is used to cool the above-mentioned equipment, devices, or manufacturing facilities and then heated and discharged to the outside as is can be used. Alternatively, unused heat may be geothermal heat. The following explanation will be given using an example where the unused heat is heated wastewater.

[0018] The first heat pump 1 is configured in a manner similar to conventional heat pumps. That is, the first heat pump 1 has a first evaporator 1a, a first compressor 1b, a first condenser 1c, and a first expansion valve 1d, and a first refrigerant is circulated between them. The first refrigerant may be a conventional refrigerant that is sealed within the first heat pump 1 and transfers heat.

[0019] The first evaporator 1a is configured to transfer heat from the hot wastewater to the first refrigerant, thereby increasing the temperature of the first refrigerant. The first compressor 1b compresses the first refrigerant, whose temperature has been increased by heat exchange in the first evaporator 1a, to a higher temperature and pressure state, and supplies the high-temperature, high-pressure first refrigerant to the first condenser 1c. The first condenser 1c is configured to produce hot water that is hotter than the hot wastewater by transferring heat from the high-temperature, high-pressure first refrigerant to the raw water.

[0020] In the example shown in FIG. 1, the hot water is configured to flow from the first condenser 1c toward the second evaporator 2a of the second heat pump 2. The hot water is cooled by heat exchange in the second evaporator 2a (described later) to become raw water, and the raw water is then flowed from the second evaporator 2a toward the first condenser 1c. In other words, a circulation path 3 for circulating raw water and hot water is formed between the first condenser 1c and the second evaporator 2a. Note that FIG. 1 shows examples of the temperature (°C) of the hot wastewater, the temperature (°C) of the first refrigerant that changes in the first heat pump 1, the temperature (°C) of the raw water and hot water, the temperature (°C) of the second refrigerant that changes in the second heat pump 2 (described later), and the temperature (°C) of the make-up water (described later). The configuration for supplying hot water to locations requiring heat (hot water) will be described later.

[0021] The first refrigerant, whose temperature has been reduced by heat exchange in the first condenser 1c, is made into a low-temperature, low-pressure state by the first expansion valve 1d, and this low-temperature, low-pressure first refrigerant is supplied to the first evaporator 1a.

[0022] As described above, in the first heat pump 1, the process of using the hot wastewater as a heat source to produce a first heat medium having a higher temperature than the hot wastewater corresponds to the first heating step in this embodiment.

[0023] The second heat pump 2 is located downstream of the first heat pump 1 in the heat transfer direction. The second heat pump 2 uses the hot water produced by the first heat pump as a heat source to heat low-temperature make-up water and produce steam from the make-up water as described above.

[0024] The above-mentioned makeup water may be, for example, distilled water, tap water, or industrial water. The above-mentioned makeup water or its steam corresponds to the second heat medium in this embodiment.

[0025] The second heat pump 2 is configured similarly to conventional heat pumps. That is, the second heat pump 2 has a second evaporator 2a, a second compressor 2b, a second condenser 2c, and a second expansion valve 2d, and circulates a second refrigerant between them. The second refrigerant may be a conventional refrigerant sealed within the second heat pump 2 to transfer heat.

[0026] The second evaporator 2a is configured to transfer heat from the hot water to the second refrigerant, thereby increasing the temperature of the second refrigerant. The second compressor 2b compresses the second refrigerant, whose temperature has been increased by heat exchange in the second evaporator 2a, to a higher temperature and pressure state, and supplies the high-temperature, high-pressure second refrigerant to the second condenser 2c. The second condenser 2c is configured to transfer heat from the high-temperature, high-pressure second refrigerant to low-temperature makeup water, thereby heating the makeup water and producing vapor from it.

[0027] The low-temperature makeup water is supplied to the second condenser 2c from a supply source (not shown). The configuration for supplying steam of makeup water to locations requiring heat (steam) will be described later.

[0028] The second refrigerant, whose temperature has been reduced by heat exchange in the second condenser 2c, is made into a low-temperature, low-pressure state by the second expansion valve 2d, and the low-temperature, low-pressure second refrigerant is supplied to the second evaporator 2a.

[0029] As described above, the process of producing steam of makeup water having a higher temperature than the hot water using the hot water as a heat source in the second heat pump 2 corresponds to the second heating step in this embodiment.

[0030] In this way, the unused heat recovery system 100 uses two heat pumps 1 and 2 connected in series to produce hot water using the hot wastewater, which is unused heat, as a heat source, and can then use the resulting hot water to produce steam for make-up water. The produced steam is supplied to locations where heat is needed. Furthermore, it is also possible to supply a portion of the hot water produced by the first heat pump to outside the unused heat recovery system. The unused heat recovery system 100 can produce and supply hot water or steam for make-up water that is appropriate for each location where heat is needed. This allows the unused heat recovery system 100 to effectively utilize unused heat throughout the year.

[0031] Fig. 2 is a diagram showing an example of equipment to which the unused heat recovery equipment according to this embodiment can be applied. Although there are no limitations on the equipment or device that discharges unused heat, an example of the equipment or device that discharges unused heat is the condenser 6 of the steam turbine 5 in the steam turbine cycle 4 shown in Fig. 2. In other words, the warm wastewater generated in the condenser 6 corresponds to the above-mentioned unused heat.

[0032] Boiler feedwater generated in condenser 6 shown in Figure 2 is supplied to steam boiler 8 by feedwater pump 7. The boiler feedwater steam generated in steam boiler 8 is supplied to steam turbine 5, which drives the steam turbine 5. The steam turbine 5 then drives a generator 9 to generate electricity. The boiler feedwater steam that has passed through steam turbine 5 is cooled by heat exchange with cooling water in condenser 6, and changes phase to liquid boiler feedwater.

[0033] The cooling water supplied to the condenser 6 may be, for example, seawater, industrial water, or tap water. In the example shown in Fig. 2, the cooling water is supplied to the condenser 6 by a cooling water pump 10. The temperature of the cooling water is then increased by heat exchange in the condenser 6, and the cooling water becomes heated wastewater. The heat thus recovered as heated wastewater is discharged to the outside of the condenser 6 via a cooling water passage 11 connected to the condenser 6.

[0034] A pipe 13 that supplies a portion of the hot wastewater to the unused heat recovery equipment 100 is connected to the cooling water channel 11, and a cooling water transfer pump 14 is provided on the pipe 13. The cooling water transfer pump 14 causes the hot wastewater to flow from the cooling water channel 11 to the unused heat recovery equipment 100. An adjustment valve 12 may be provided downstream of the connection point of the cooling water channel 11 with the pipe 13 to facilitate the supply of a portion of the hot wastewater to the unused heat recovery equipment 100. A heat exchanger 15 is connected to the pipe 13 downstream of the cooling water transfer pump 14. The heat exchanger 15 is configured to transfer heat from the hot wastewater to raw heat water such as tap water or industrial water. Meanwhile, the hot wastewater, i.e., cooling water, that has been cooled by heat exchange in the heat exchanger 15 is returned to the cooling water channel 11.

[0035] 2, the heat exchanger 15 and the first evaporator 1a of the first heat pump 1 are connected via heat source water. This is to prevent corrosion of the first heat pump 1 due to salt contained in seawater when the cooling water is seawater.

[0036] Returning to the explanation of Figure 2, a heat source water circulation path 16 is formed between the heat exchanger 15 and the first evaporator 1a to circulate the heat source water. A heat source water pump 17 is provided in the heat source water circulation path 16. Low-temperature heat source water is supplied to the heat exchanger 15 by the heat source water pump 17. In the heat exchanger 15, heat is exchanged between the above-mentioned warm wastewater and the low-temperature heat source water, and the heat source water whose temperature has increased as a result is stored in a heat source water tank 18.

[0037] A heat source water pump 17 is provided downstream of the heat source water tank 18 in the flow direction of the heat source water in the heat source water circulation path 16, and a first evaporator 1a of the first heat pump 1 is connected downstream of the heat source water pump 17. The first heat pump 1 shown in Figure 2 is configured in the same manner as the first heat pump 1 shown in Figure 1 described above. Therefore, components similar to those of the first heat pump 1 shown in Figure 1 are assigned the same reference numerals, and their description will be omitted.

[0038] A hot water tank 19 is provided downstream of the first condenser 1c in the flow direction of water (hot water) in the circulation path 3, i.e., in the direction of heat transfer. In addition, a hot water tank flow rate adjustment valve 20 is provided between the first condenser 1c and the hot water tank 19 in the circulation path 3 to adjust the flow rate of hot water flowing toward the hot water tank 19. As an example, when hot water is supplied to the vaporizer 22, the hot water tank flow rate adjustment valve 20 reduces the flow rate of hot water flowing toward the hot water tank 19.

[0039] A hot water pump 21 is provided downstream of the hot water tank 19 in the circulation path 3 in the flow direction. The hot water pump 21 supplies hot water from the hot water tank 19 to the second evaporator 2a, and also supplies raw water generated by heat exchange in the second evaporator 2a to the first condenser 1c. The second heat pump 2 shown in FIG. 2 has the same configuration as the second heat pump 2 shown in FIG. 1 described above. Therefore, the same components as those in the second heat pump 2 shown in FIG. 1 are denoted by the same reference numerals, and their description will be omitted.

[0040] Furthermore, in this embodiment, the hot water produced as described above is supplied to vaporizer 22 and used as a heat source for vaporizing liquefied gas in vaporizer 22. In the example shown in FIG. 2 , a hot water supply pipe 23, which corresponds to the first supply pipe in this embodiment and supplies hot water to vaporizer 22, is connected upstream of hot water tank-directed flow control valve 21 in the hot water flow direction in circulation path 3. A vaporizer-directed flow rate adjustment valve 24 and a vaporizer-directed automatic flow rate adjustment valve 25 are provided upstream of vaporizer 22 in hot water supply pipe 23. Vaporizer-directed flow rate adjustment valve 24 is located upstream of vaporizer-directed automatic flow rate adjustment valve 25. These two adjustment valves 24 and 25 enable adjustment of the flow rate of hot water flowing toward vaporizer 22. A vaporizer-directed hot water transfer pump that supplies hot water to vaporizer 22 may be provided in hot water supply pipe 23.

[0041] In addition, in the vaporizer 22, the hot water, i.e., raw water, whose temperature has been reduced by being used as a heat source for vaporizing the liquefied gas, is returned to the hot water tank 19 via a return pipe 26.

[0042] In the example shown in Figure 2, the makeup water vapor generated in the second condenser 2c of the second heat pump 2 is supplied to the adsorber 29 of the cryogenic separation device 28 via a vapor pipe 27, which corresponds to the second supply pipe in this embodiment.

[0043] As shown in Fig. 2, the steam pipe 27 is provided with a pressure gauge 30 that monitors fluctuations in the steam pressure inside the steam pipe 27. A steam diffusion control valve 31 is provided upstream of the pressure gauge 30 in the flow direction of the steam from the makeup water in the steam pipe 27. The steam diffusion control valve 31 is configured to communicate between the inside and outside of the steam pipe 27 and release the pressure in the steam pipe 27 to the outside when the steam pressure in the steam pipe 27 reaches or exceeds a preset pressure. A steam silencer 32 that suppresses noise and vibration generated when the pressure in the steam pipe 27 is released is provided at a discharge port (not shown) of the steam diffusion control valve 31. The steam diffusion control valve 31 may be what is called a relief valve or a safety valve.

[0044] The cryogenic separation device 28 may be a conventionally known device that separates various gases contained in air by utilizing the difference in their boiling points. In the example shown in Fig. 2, air is taken into an air compressor 34 via an air filter 33. The air compressed by the air compressor 34 (hereinafter referred to as compressed air) is supplied to the adsorber 29 via a water washing tower 35. In the adsorber 29, carbon dioxide and moisture contained in the compressed air are adsorbed by an adsorbent material (not shown) and removed.

[0045] When the amount of carbon dioxide and moisture adsorbed by the adsorbent reaches or exceeds a preset threshold, the adsorbent is heated, vaporizing the carbon dioxide and moisture adsorbed by the adsorbent and releasing them to the outside, thereby regenerating the adsorber 29.

[0046] The compressed air that has passed through the adsorber 29 is supplied to the cryogenic separator 28, where it is further cooled and converted to a liquid phase. It is then separated and purified into nitrogen gas, oxygen gas, and argon gas by utilizing the differences in boiling points. Each gas is then cooled to produce a liquefied gas. The liquefied gas is supplied to the liquefied gas storage facility 36 and stored.

[0047] Liquefied gas is transported from liquefied gas storage facility 36 to vaporizer 22 by liquefied gas transport pump 37. The gas produced in vaporizer 22 is then supplied to a location (not shown) that requires the gas via gas supply pipe 38. A gas thermometer 39 is provided midway through gas supply pipe 38. It is preferable to control the amount of hot water supplied to vaporizer 22 by controlling flow rate control valves 24 and 25 based on the gas temperature measured by gas thermometer 39.

[0048] (Actions and Effects) In the unused heat recovery system 100 of this embodiment, hot water is produced by recovering heat from warm wastewater, and the hot water is used as a heat source to produce steam. In the unused heat recovery system 100, two heat pumps 1 and 2 are connected in series, making it possible to supply heat at appropriate temperatures to multiple pieces of equipment that require heat at temperatures higher than the unused heat. Specifically, as described above, hot water can be supplied to the vaporizer 22 to vaporize the liquefied gas. In addition, steam from makeup water can be supplied to the adsorber 29 of the cryogenic separation unit 28 to regenerate the adsorber 29.

[0049] Furthermore, in the unused heat recovery system 100 of this embodiment, two heat pumps 1 and 2 connected in series are used to gradually increase the temperature of heat recovered from warm wastewater to produce steam for make-up water. In other words, the amount of energy required to produce steam for make-up water can be reduced compared to producing steam for make-up water by heating room-temperature make-up water without recovering heat from exhaust heat. Furthermore, the hot water and steam for make-up water described above are supplied to and used by the vaporizer 22 and adsorber 29 that require them. In other words, the seasons in which the hot water and steam for make-up water described above can be used are not limited. Therefore, the unused heat recovery system 100 of this embodiment can effectively utilize unused heat throughout the year. This method of recovering heat from warm wastewater, which is unused heat, corresponds to the unused heat recovery method of this embodiment.

[0050] The present invention is not limited to the above-described embodiment. For example, instead of the hot wastewater from the condenser 6, the waste heat used for heat recovery may be waste heat generated during the manufacturing process of various products, waste heat generated by air conditioning or heating, or waste heat generated by the temperature difference between domestic wastewater or sewage and the atmosphere. Even when such waste heat is used as the heat source for the first heat pump 1 in the unused heat recovery system 100, substantially the same functions and effects as those of the above-described embodiment can be obtained. Furthermore, in the above-described embodiment, the hot wastewater from the condenser 6 is connected to the first heat pump 1 via heat source water. However, instead of this, the hot wastewater from the condenser 5 may be directly connected to the first heat pump 1 without using heat source water, and heat exchange may be performed between them. This configuration can reduce heat loss due to the use of heat source water, thereby improving the waste heat recovery efficiency compared to the above-described embodiment. Furthermore, the above-described unused heat recovery system 100 may have three or more heat pumps connected in series. This configuration can reduce the load on each heat pump. Furthermore, each heat pump can produce hot water or steam for makeup water at different temperatures. In other words, it is possible to produce hot water or steam for makeup water at various temperatures suited to the locations requiring heat. Even with this configuration, it is possible to obtain functions and effects similar to those of the present embodiment described above. [Explanation of symbols]

[0051] 100 Unused heat recovery equipment 1. First heat pump 1a First evaporator 1b First compressor 1c First condenser 1d First expansion valve 2. Secondary heat pump 2a Second evaporator 2b Second compressor 2c Second condenser 2d Second expansion valve 3 Circulation route 4 Steam turbine cycle 5. Steam turbine 6. Condenser 7. Water supply pump 8 Steam Boiler 9. Generator 10 Cooling water pump 11 Cooling Channel 12 Flow control valve 13 Piping 14 Cooling water transfer pump 15 Heat exchanger 16 Thermal water circulation route 17 Heat source water pump 18. Thermal raw water tank 19 Hot water tank 20 Hot water tank flow control valve 21 Hot water pump 22 Vaporizer 23 Hot water supply pipe 24 Vaporizer flow control valve 25 Automatic flow control valve for vaporizer 26 Return pipe 27 Steam Pipe 28 Cryogenic separation equipment 29 Adsorption device 30 Pressure Gauge 31 Steam release control valve 32 Steam silencer 33 Air filter 34 Air Compressor 35 Washing tower 36 Liquefied gas storage facilities 37 Liquefied gas transport pump 38 Gas supply pipe 39 Gas thermometer

Claims

1. An unused heat recovery facility that recovers unused heat, a first heat pump that uses the unused heat as a heat source to produce a first heat medium having a temperature higher than that of the unused heat; and a second heat pump that uses the high-temperature first heat medium produced by the first heat pump as a heat source to produce a second heat medium that is even hotter than the high-temperature first heat medium.

2. 2. The unused heat recovery equipment according to claim 1, further comprising a tank disposed between the first heat pump and the second heat pump in the heat transfer direction, the tank storing the high-temperature first heat medium produced by the first heat pump.

3. 2. The unused heat recovery facility according to claim 1, wherein the unused heat is hot wastewater from a condenser of a steam turbine.

4. 3. The unused heat recovery facility according to claim 2, wherein the unused heat is hot wastewater discharged from a condenser of a steam turbine.

5. 2. The unused heat recovery facility according to claim 1, further comprising a first supply pipe for supplying a high-temperature first heat medium produced by the first heat pump to a vaporizer that vaporizes liquefied gas.

6. 3. The unused heat recovery facility according to claim 2, further comprising a first supply pipe for supplying a high-temperature first heat medium produced by the first heat pump to a vaporizer that vaporizes liquefied gas.

7. 4. The unused heat recovery facility according to claim 3, further comprising a first supply pipe for supplying the high-temperature first heat medium produced by the first heat pump to a vaporizer that vaporizes the liquefied gas.

8. 5. The unused heat recovery facility according to claim 4, further comprising a first supply pipe for supplying the high-temperature first heat medium produced by the first heat pump to a vaporizer that vaporizes the liquefied gas.

9. 2. The unused heat recovery equipment according to claim 1, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

10. 3. The unused heat recovery equipment according to claim 2, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

11. The unused heat recovery equipment according to claim 3, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

12. 5. The unused heat recovery equipment according to claim 4, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorber of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

13. 6. The unused heat recovery equipment according to claim 5, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

14. 7. The unused heat recovery equipment according to claim 6, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorbent of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

15. 8. The unused heat recovery equipment according to claim 7, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorber of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

16. 9. The unused heat recovery equipment according to claim 8, further comprising a second supply pipe for supplying the high-temperature second heat medium produced by the second heat pump to an adsorber of a cryogenic separation device that adsorbs and removes carbon dioxide contained in the air.

17. A method for recovering unused heat, comprising: a first heating step of producing a first heat medium having a temperature higher than that of the unused heat using the unused heat as a heat source; a second heating step of producing a second heat medium having an even higher temperature than the high-temperature first heat medium using the high-temperature first heat medium produced in the first heating step as a heat source.

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