Power generation system

Abstract

A power generation system 10 comprises: a boiler 3 that combusts fuel containing ammonia; a turbine 41 that is circulatively connected to the boiler 3 and driven by steam from the boiler 3; a condenser 5 that is circulatively connected to the boiler 3 and the turbine 41, cools the vapor discharged from the turbine 41, and supplies condensed water to the boiler 3; an evaporator 2 that is connected to an ammonia supply source 1 and the boiler 3, heats liquid ammonia from the ammonia supply source 1, and supplies the heated ammonia to the boiler 3; and at least one line L4 that thermally connects the evaporator 2 and the condenser 5 and transmits cold energy of the liquid ammonia flowing in the evaporator 2, to the condenser 5.

Description

[Technical Field]

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2022-101752, filed on June 24, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Ammonia is known as a fuel that does not emit CO2. For example, Patent Document 1 discloses a power generation system that uses ammonia as fuel. In this system, ammonia is stored in a liquid state. The liquid ammonia is vaporized and burned in a gaseous state in a boiler. Steam from the boiler rotates a turbine and a generator. The steam is condensed into water in a condenser. In this system, seawater is used to condense the steam in the condenser. After passing through the condenser, the seawater passes through a vaporizer and is used to vaporize ammonia. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 184612 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described system, it is desirable to further improve the power generation efficiency.

[0005] An object of the present disclosure is to provide a power generation system that can improve power generation efficiency. [Means for solving the problem]

[0006] A power generation system according to one aspect of the present disclosure includes: a boiler that burns fuel containing ammonia; a turbine that is cyclically connected to the boiler and driven by steam from the boiler; a condenser that is cyclically connected to the boiler and the turbine, the condenser cooling steam discharged from the turbine and supplying condensed water to the boiler; a single vaporizer that is connected to an ammonia supply source and the boiler, the single vaporizer heating liquid ammonia from the ammonia supply source and supplying the heated ammonia to the boiler; and at least one line that thermally connects the single vaporizer and the condenser, the at least one line transferring cold energy of the liquid ammonia flowing through the single vaporizer to the condenser. At least one line includes a first line connected to a condenser, in which a first heat medium flows through the first line; a second line circulatingly connected to the single vaporizer, in which a second heat medium flows through the second line; and a heat exchanger disposed between the first line and the second line, in which the first heat medium flowing through the first line is cooled by the second heat medium cooled by liquid ammonia in the single vaporizer and flowing through the second line, the second heat medium being a fluid having a freezing point lower than the freezing point of the first heat medium. . A power generation system according to another aspect of the present disclosure includes a boiler that burns fuel containing ammonia, a turbine that is circulatory connected to the boiler and driven by steam from the boiler, a condenser that is circulatory connected to the boiler and the turbine, the condenser cooling steam discharged from the turbine and supplying condensed water to the boiler, a single vaporizer that is connected to an ammonia supply source and the boiler, the single vaporizer heating liquid ammonia from the ammonia supply source and supplying the heated ammonia to the boiler, and at least one line thermally connecting the single vaporizer and the condenser. and at least one line that transfers the cold energy of the liquid ammonia flowing through the single vaporizer to the condenser, the at least one line including: a first line that directly connects the single vaporizer and the condenser, a first heat medium flowing through the first line, and the first heat medium cooled by liquid ammonia in the single vaporizer being sent to the condenser; and a second line that cyclically connects the single vaporizer and the condenser, a second heat medium flowing through the second line, and the second heat medium cooled by liquid ammonia in the single vaporizer being sent to the condenser. [Effects of the Invention]

[0010] According to the present disclosure, power generation efficiency can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a power generation system according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a power generation system according to the second embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a power generation system according to the third embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a power generation system according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0013] FIG. 1 is a schematic diagram showing a power generation system 10 according to a first embodiment. Hereinafter, the power generation system 10 may also be simply referred to as a "system." In FIG. 1, solid arrows indicate the flow of liquid, and dashed arrows indicate the flow of gas. The system 10 includes, for example, a tank (ammonia supply source) 1, a vaporizer 2, a boiler 3, a turbine generator 4, and a condenser 5. The components of the system 10 are not limited to these, and the system 10 may further include other components.

[0014] Tank 1 stores ammonia. Specifically, tank 1 stores liquid ammonia. Tank 1 is connected to vaporizer 2 by a flow path L1. Liquid ammonia in tank 1 is supplied to vaporizer 2 by flow path L1. A first pump P1 for sending liquid ammonia is provided in flow path L1.

[0015] Vaporizer 2 heats liquid ammonia from tank 1 using a heat medium flowing through flow path L4, which will be described in detail later. Vaporizer 2 exchanges heat between the heat medium and the liquid ammonia. The heated liquid ammonia vaporizes into gaseous ammonia. Vaporizer 2 is connected to boiler 3 through flow path L2. The vaporized ammonia is supplied to boiler 3 through flow path L2.

[0016] The boiler 3 burns fuel containing gaseous ammonia from the vaporizer 2. For example, the boiler 3 may burn a mixed fuel containing ammonia and another fuel such as pulverized coal. Alternatively, for example, the boiler 3 may burn only ammonia. Alternatively, for example, the boiler 3 may burn only a fuel other than ammonia, as needed. The boiler 3 heats water by heat from combustion to generate steam.

[0017] The turbine generator 4 includes a turbine 41 and a generator 42 .

[0018] The turbine 41 is circulatory connected to the boiler 3 by a circulation flow path L3. Steam generated in the boiler 3 is supplied to the turbine 41 by the circulation flow path L3. The turbine 41 is rotated by the steam from the boiler 3. The generator 42 is connected to the turbine 41. The generator 42 rotates together with the turbine 41 to generate electricity.

[0019] The condenser 5 is circulatory connected to the turbine 41 by a circulation flow path L3. The condenser 5 is also connected to the vaporizer 2 by a flow path L4. The condenser 5 cools the steam discharged from the turbine 41 by a heat medium flowing through the flow path L4. The steam is condensed into water. The condensed water is supplied again to the boiler 3 and heated into steam. A second pump P2 for circulating the water is provided in the circulation flow path L3.

[0020] A flow path (first line) L4 directly connects the vaporizer 2 and the condenser 5. A heat medium (first heat medium) flows through the flow path L4. The flow path L4 is configured so that the heat medium flows from the vaporizer 2 to the condenser 5. A third pump P3 that sends the heat medium in a direction from the vaporizer 2 toward the condenser 5 is provided in the flow path L4.

[0021] For example, the third pump P3 may pump seawater from the sea as the heat medium. When seawater is used as the heat medium, the seawater may be discharged into the sea after passing through the condenser 5. Alternatively or additionally, the third pump P3 may pump water from a river as the heat medium. When river water is used as the heat medium, the water may be discharged into the river after passing through the condenser 5. Alternatively or additionally, for example, when the system 10 is constructed in a location far from the sea and a river, the third pump P3 may receive water from a cooling tower as the heat medium. When water from a cooling tower is used as the heat medium, the water may be circulated and reused. The heat medium is not limited to these, and other fluids may be used.

[0022] In this embodiment, flow path L4 branches into flow paths L41 and L42 at a position upstream of the vaporizer 2. A valve (not shown) may be provided at the branching point to adjust the flow rate of vapor flowing through flow paths L41 and L42. Flow paths L41 and L42 merge with each other at a position downstream of the vaporizer 2. The vaporizer 2 is provided on flow path L41. Flow path L42 bypasses the vaporizer 2. In other embodiments, flow path L42 may not be provided.

[0023] Next, the operation of the system 10 will be described.

[0024] Liquid ammonia in tank 1 is supplied to vaporizer 2 via flow path L1. Vaporizer 2 heats the liquid ammonia using a heat transfer medium flowing through flow path L4. The heated liquid ammonia is vaporized into gaseous ammonia. The vaporized ammonia is supplied to boiler 3 via flow path L2.

[0025] The boiler 3 burns fuel containing gaseous ammonia from the vaporizer 2. The boiler 3 heats water with heat from the combustion to generate steam. The steam generated in the boiler 3 is supplied to the turbine 41 through the circulation flow path L3. The turbine 41 is rotated by the steam from the boiler 3. The generator 42 rotates together with the turbine 41 to generate electricity.

[0026] The condenser 5 cools the steam discharged from the turbine 41 by the heat medium flowing through the flow path L4. The steam is condensed into water. The condensed water is supplied to the boiler 3 again and heated to become steam.

[0027] In flow path L4, the heat transfer medium flows in a direction from the vaporizer 2 toward the condenser 5. Therefore, the heat transfer medium cooled by the liquid ammonia in the vaporizer 2 is supplied to the condenser 5. That is, flow path L4 transfers the cold energy of the liquid ammonia flowing through the vaporizer 2 to the condenser 5. Therefore, compared to when a heat transfer medium such as seawater is directly supplied to the condenser 5, the steam flowing through the condenser 5 is cooled more, and the pressure inside the condenser 5 is further reduced. With this configuration, more steam can be drawn from the turbine 41 into the condenser 5, and the operating conditions of the turbine 41 can be expanded. Therefore, the power generation efficiency of the system 10 is improved.

[0028] The system 10 as described above includes a boiler 3 that burns a fuel containing ammonia, a turbine 41 that is circulatory connected to the boiler 3 and driven by steam from the boiler 3, a condenser 5 that is circulatory connected to the boiler 3 and the turbine 41 and that cools steam discharged from the turbine 41 and supplies condensed water to the boiler 3, a vaporizer 2 that is connected to the tank 1 and the boiler 3 and that heats liquid ammonia from the tank 1 and supplies the heated ammonia to the boiler 3, and a flow path L4 that thermally connects the vaporizer 2 and the condenser 5 and transfers cold energy of the liquid ammonia flowing through the vaporizer 2 to the condenser 5. According to this configuration, the cold energy of the liquid ammonia flowing through the vaporizer 2 is used to condense water in the condenser 5. Therefore, compared to when a heat medium such as seawater is directly supplied to the condenser 5, the steam flowing through the condenser 5 is cooled more, and the pressure in the condenser 5 is reduced more. Therefore, more steam can be drawn from the turbine 41 into the condenser 5, and the operating conditions of the turbine 41 can be expanded. As a result, the power generation efficiency of the system 10 can be improved.

[0029] Furthermore, in system 10, the line thermally connecting vaporizer 2 and condenser 5 includes flow path L4 that directly connects vaporizer 2 and condenser 5, and a heat medium flows through flow path L4, and the heat medium is cooled by liquid ammonia in vaporizer 2 and sent to condenser 5. According to this configuration, for example, by adjusting the flow rate of the heat medium, it is possible to adjust the cooling of steam and avoid insufficient or excessive cooling of steam, regardless of the flow rate of liquid ammonia passing through vaporizer 2. Therefore, the operating conditions of turbine 41 can be finely adjusted.

[0030] Next, other embodiments will be described.

[0031] 2 is a schematic diagram showing a power generation system 10A according to the second embodiment. The system 10A differs from the system 10 of the first embodiment in that a circulation flow path (second line) L5 ​​and a heat exchanger 6 are added between the vaporizer 2 and the condenser 5. In other respects, the system 10A may be the same as the system 10.

[0032] In this embodiment, the flow path L4 passes through a heat exchanger 6 instead of the vaporizer 2. The circulation flow path L5 circulates between the vaporizer 2 and the heat exchanger 6. A heat medium (second heat medium) flows through the circulation flow path L5. A fourth pump P4 for circulating the heat medium is provided in the circulation flow path L5.

[0033] For example, the second heat medium may be brine containing sodium chloride. The second heat medium is not limited to this, and other fluids may be used. For example, the second heat medium may be a fluid having a freezing point lower than the freezing point of the first heat medium.

[0034] The heat exchanger 6 is disposed between the flow path L4 and the circulation flow path L5. The heat exchanger 6 exchanges heat between the first heat medium flowing through the flow path L4 and the second heat medium flowing through the circulation flow path L5.

[0035] Next, the operation of the system 10A will be described, focusing on the differences from the system 10 of the first embodiment.

[0036] In circulation flow path L5, the second heat medium circulates between the vaporizer 2 and the heat exchanger 6. Therefore, the second heat medium cooled by liquid ammonia in the vaporizer 2 is supplied to the heat exchanger 6. The heat exchanger 6 cools the first heat medium flowing in flow path L4 with the second heat medium flowing in circulation flow path L5.

[0037] In flow path L4, the first heat medium flows in a direction from the heat exchanger 6 toward the condenser 5. Therefore, the first heat medium cooled by the second heat medium in the heat exchanger 6 is supplied to the condenser 5. That is, the circulation flow path L5, the heat exchanger 6, and the flow path L4 transfer the cold energy of the liquid ammonia flowing through the vaporizer 2 to the condenser 5. Therefore, compared to when a heat medium such as seawater is directly supplied to the condenser 5, the steam flowing through the condenser 5 is cooled more, and the pressure inside the condenser 5 is reduced more.

[0038] According to the system 10A described above, similarly to the system 10 of the first embodiment, it is possible to draw more steam from the turbine 41 into the condenser 5, thereby expanding the operating conditions of the turbine 41. Therefore, the power generation efficiency of the system 10A is improved.

[0039] In addition, in the system 10A, the line thermally connecting the vaporizer 2 and the condenser 5 includes a flow path L4 connected to the condenser 5, through which a first heat medium flows; a circulation flow path L5 connected to the vaporizer 2 in a circulating manner, through which a second heat medium flows; and a heat exchanger 6 disposed between the flow paths L4 and L5, which cools the first heat medium flowing through the flow path L4 with the second heat medium cooled by liquid ammonia in the vaporizer 2 and flowing through the circulation flow path L5. With this configuration, for example, the cooling of the steam can be adjusted by adjusting the flow rate of the second heat medium in addition to adjusting the flow rate of the first heat medium. This allows for more precise adjustment of the operating conditions of the turbine 41.

[0040] Next, still another embodiment will be described.

[0041] 3 is a schematic diagram showing a power generation system 10B according to a third embodiment. The system 10B differs from the system 10A of the second embodiment in that the system 10B does not include a flow path L4 and a heat exchanger 6. In other respects, the system 10B may be the same as the system 10A.

[0042] In this embodiment, the circulation flow path L5 passes through the condenser 5 instead of the heat exchanger 6. The circulation flow path L5 connects the vaporizer 2 and the condenser 5 in a circulatory manner.

[0043] Next, the operation of the system 10B will be described, focusing on the differences from the system 10A of the second embodiment.

[0044] In the circulation flow path L5, the second heat medium circulates between the vaporizer 2 and the condenser 5. Therefore, the second heat medium cooled by the liquid ammonia in the vaporizer 2 is supplied to the condenser 5. The condenser 5 cools the steam flowing through the condenser 5 by the second heat medium flowing through the circulation flow path L5. That is, the circulation flow path L5 transfers the cold energy of the liquid ammonia flowing through the vaporizer 2 to the condenser 5. Therefore, compared to when a heat medium such as seawater is directly supplied to the condenser 5, the steam flowing through the condenser 5 is cooled more, and the pressure inside the condenser 5 is reduced more.

[0045] According to the system 10B described above, similarly to the systems 10 and 10A, it is possible to draw more steam from the turbine 41 into the condenser 5, thereby expanding the operating conditions of the turbine 41. Therefore, the power generation efficiency of the system 10B is improved.

[0046] Furthermore, in system 10B, the line thermally connecting vaporizer 2 and condenser 5 includes a circulation flow path L5 that circulates between vaporizer 2 and condenser 5. A second heat medium flows through circulation flow path L5, and the second heat medium is cooled by liquid ammonia in vaporizer 2 and sent to condenser 5. With this configuration, for example, the cooling of steam can be adjusted by adjusting the flow rate of the second heat medium. Therefore, the operating conditions of turbine 41 can be finely adjusted. Furthermore, system 10B does not use a first heat medium, such as seawater. Therefore, there is no leakage of liquid ammonia into seawater.

[0047] Next, still another embodiment will be described.

[0048] 4 is a schematic diagram showing a power generation system 10C according to a fourth embodiment. The system 10C differs from the system 10A according to the second embodiment in that a circulation flow path L5 is provided between the vaporizer 2 and the condenser 5 in parallel with the flow path L4, and a heat exchanger 6 is not provided. In other respects, the system 10C may be the same as the system 10A. From another perspective, the system 10C can be said to include a combination of the flow path L4 of the first embodiment and the circulation flow path L5 of the third embodiment.

[0049] According to the system 10C described above, similarly to the above-described systems 10, 10A, and 10B, it is possible to draw more steam from the turbine 41 into the condenser 5, thereby expanding the operating conditions of the turbine 41. Therefore, the power generation efficiency of the system 10B is improved.

[0050] In addition, in system 10C, the line thermally connecting vaporizer 2 and condenser 5 includes a flow path L4 that directly connects vaporizer 2 and condenser 5. A first heat medium flows through this flow path L4, and the first heat medium, which is cooled by liquid ammonia in vaporizer 2, is sent to condenser 5. Furthermore, the line thermally connecting vaporizer 2 and condenser 5 includes a circulation flow path L5 that circulates between vaporizer 2 and condenser 5. A second heat medium flows through this circulation flow path L5, and the second heat medium, which is cooled by liquid ammonia in vaporizer 2, is sent to condenser 5. With this configuration, for example, the cooling of steam can be adjusted by adjusting the flow rates of both the first and second heat mediums. Therefore, the operating conditions of turbine 41 can be more precisely adjusted.

[0051] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that such modifications also fall within the technical scope of the present disclosure.

[0052] For example, the system 10B of the third embodiment may include an additional flow path that passes through the condenser 5 without passing through the vaporizer 2, and seawater or river water may flow through this flow path.

[0053] The disclosure can promote the use of ammonia, which leads to reduced CO2 emissions, and thereby contribute, for example, to Sustainable Development Goals (SDGs) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy" and Goal 13 "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0054] 1 tank (ammonia supply source) 2. Vaporizer 3. Boiler 5 Condenser 6 Heat exchanger 10 Power Generation System 10A power generation system 10B Power Generation System 10C Power Generation System 41 Turbine L4 flow path (first line) L5 Circulation flow path (second line)

Claims

1. a boiler that burns fuel containing ammonia; a turbine cyclically connected to the boiler and driven by steam from the boiler; a condenser circulatingly connected to the boiler and the turbine, the condenser cooling steam discharged from the turbine and supplying condensed water to the boiler; a single vaporizer connected to an ammonia supply source and the boiler, the single vaporizer heating liquid ammonia from the ammonia supply source and supplying the heated ammonia to the boiler; At least one line thermally connecting the single vaporizer and the condenser, the at least one line transferring cold energy of the liquid ammonia flowing through the single vaporizer to the condenser; Equipped with The at least one line is a first line connected to the condenser, through which a first heat medium flows; a second line circulatingly connected to the single vaporizer, through which a second heat medium flows; A heat exchanger disposed between the first line and the second line, the heat exchanger cooling the first heat medium flowing through the first line by the second heat medium cooled by the liquid ammonia in the single vaporizer and flowing through the second line; Including, The second heat medium is a fluid having a freezing point lower than the freezing point of the first heat medium. Power generation system.

2. a boiler that burns fuel containing ammonia; a turbine cyclically connected to the boiler and driven by steam from the boiler; a condenser circulatingly connected to the boiler and the turbine, the condenser cooling steam discharged from the turbine and supplying condensed water to the boiler; a single vaporizer connected to an ammonia supply source and the boiler, the single vaporizer heating liquid ammonia from the ammonia supply source and supplying the heated ammonia to the boiler; At least one line thermally connecting the single vaporizer and the condenser, the at least one line transferring cold energy of the liquid ammonia flowing through the single vaporizer to the condenser; Equipped with The at least one line is a first line directly connecting the single vaporizer and the condenser, through which a first heat medium flows, and the first heat medium cooled by the liquid ammonia in the single vaporizer is sent to the condenser; a second line circulatingly connecting the single vaporizer and the condenser, through which a second heat medium flows, and the second heat medium cooled by the liquid ammonia in the single vaporizer is sent to the condenser; Including, Power generation system.

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