Steam-water thermodynamic cycle system of thermal power plant

Abstract

The steam-water thermodynamic cycle system comprises a steam boiler, one side of the steam boiler is connected with a water conveying pipe, the other side of the steam boiler is connected with an air inlet of a steam turbine through a first connecting pipe, one end of the water conveying pipe is connected with the steam boiler, and the other end of the water conveying pipe extends into a water injection tank. An air outlet of the steam turbine is communicated with a heat exchange box through a second connecting pipe, a heat exchange pipe is arranged at the bottom of the heat exchange box, a water inlet and a water outlet of the heat exchange pipe are connected with the water storage tank through a water inlet pipe and a water outlet pipe respectively, and a pump body is installed on the water inlet pipe; a top cover is arranged on the upper portion of the heat exchange box, the side edge of the top cover is connected with one end of an air return pipe, and the other end of the air return pipe extends into the water injection box. Low-pressure steam generated during thermal power generation is recycled, the steam utilization efficiency is improved, and then fuel consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal cycle equipment of thermal power plants, and in particular relates to a steam-water thermal cycle system of a thermal power plant. Background Art

[0002] Thermal power plants generate electricity by converting the heat energy generated by the combustion of fuel into mechanical energy, which is further converted into electrical energy through a power generation device. There are three forms of energy conversion processes in thermal power generation: fuel chemical energy → steam thermal energy → mechanical energy → electrical energy. For example, high-pressure steam drives the operation of a steam turbine to convert steam thermal energy into mechanical energy. After the high-pressure steam expands and does work in the steam turbine, it becomes low-pressure steam and still has heat. If the low-pressure steam is discharged directly, a large amount of heat energy will be wasted, and in turn, the fuel consumed to generate heat energy will be wasted. Summary of the invention

[0003] The present application proposes a steam-water thermodynamic cycle system for a thermal power plant, which is used to recycle the low-pressure steam generated during thermal power generation, improve the steam utilization efficiency, and further reduce fuel consumption.

[0004] To achieve the above objectives, this application provides the following technical solutions:

[0005] A steam-water thermal cycle system of a thermal power plant comprises a steam boiler, one side of the steam boiler is connected to a water delivery pipe, the other side of the steam boiler is connected to an air inlet of a steam turbine through a first connecting pipe, one end of the water delivery pipe is connected to the steam boiler, the other end of the water delivery pipe extends into a water injection tank, a water pump is arranged at a port at the other end of the water delivery pipe, one side of the water injection tank is connected to a water adding pipe, the air outlet of the steam turbine is connected to a heat exchange box through a second connecting pipe, a heat exchange pipe is arranged at the bottom of the heat exchange box, the water inlet and the water outlet of the heat exchange pipe are connected to a water storage tank through a water inlet pipe and a water outlet pipe respectively, a pump body is installed on the water inlet pipe, a top cover is arranged on the upper part of the heat exchange box, the side of the top cover is connected to one end of a return air pipe, the other end of the return air pipe extends into the water injection tank, and an air pump is arranged on the return air pipe.

[0006] In one embodiment of the present application, the water inlet of the water filling pipe is arranged downward, and a first control valve is installed at the water inlet of the water filling pipe.

[0007] In one embodiment of the present application, a first one-way control valve is provided at the connection between the water pipe and the steam boiler.

[0008] In one embodiment of the present application, an annular tube is connected to one end of the return air pipe extending into the water injection tank, and a plurality of ventilation holes are provided on the upper end surface of the annular tube.

[0009] In one embodiment of the present application, a second one-way control valve is installed on the upper end surface of the water injection tank.

[0010] In one embodiment of the present application, a third one-way control valve is provided at the connection between the second connecting pipe and the heat exchange box.

[0011] In one embodiment of the present application, the inner wall of the top cover of the heat exchange box is inclined.

[0012] In one embodiment of the present application, the heat exchange tube is arranged in a bent shape at the bottom of the heat exchange box, and a circular ring sheet is sleeved on the outer side of the tube body of the heat exchange tube.

[0013] In one embodiment of the present application, a drain pipe is connected to the bottom end of the heat exchange box, the drain pipe is connected to the water storage tank, and an electric control valve is installed on the drain pipe.

[0014] In one embodiment of the present application, the outer walls of the water injection tank and the water storage tank are covered with an insulation layer.

[0015] In summary, the technical solution proposed in this application includes the following beneficial technical effects: This application fills the water tank with general water, and pressurizes the water in the water tank and injects it into the heat exchange tube through the water pump installed on the water inlet pipe. The heat exchange tube exchanges heat with the liquefied steam in the heat exchange box, which can avoid direct contact with the softened water in the heat exchange box, which is beneficial to improve the purity of the hot water. The hot water in the heat exchange tube flows through the heat exchange tube and then flows back to the water tank through the outlet pipe. Such a reciprocating cycle can increase the water temperature in the water tank, especially in high-altitude and cold areas where hot water resources are relatively scarce. The hot water in the water tank can be used for heating or bathing of employees, thereby improving the living environment of employees. In addition, hot water can be sold as a heat source to reduce the operating costs of thermal power plants. The side of the top cover is connected to one end of the return air pipe, and the other end of the return air pipe extends into the water injection tank. An air pump is provided on the return air pipe. When the air pump is turned on, the unliquefied steam on the top of the heat exchange box can be extracted and then injected into the water injection tank through the return air pipe. The steam in the return air pipe contacts the filling water in the water injection tank for heat exchange, which can increase the initial water temperature in the water injection tank, thereby reducing the fuel consumed by the steam boiler for heating, so as to realize the recycling of steam heat, improve the steam utilization efficiency, and thus reduce the fuel consumption during power generation in thermal power plants, reduce the fuel costs of enterprises, and thus reduce production costs, and reduce greenhouse gas emissions and the release of other pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of the three-dimensional structure of a steam-water thermodynamic cycle system of a thermal power plant provided in one embodiment of the present application;

[0018] Figure 2 A schematic diagram of the cross-sectional structure of a water injection tank of a steam-water thermodynamic cycle system of a thermal power plant provided in one embodiment of the present application;

[0019] Figure 3 A schematic diagram of the connection and coordination structure of a steam boiler and a steam turbine of a steam-water thermal cycle system of a thermal power plant provided in one embodiment of the present application;

[0020] Figure 4 A schematic diagram of the installation structure of a heat exchange box of a steam-water thermal cycle system of a thermal power plant provided in one embodiment of the present application;

[0021] Figure 5 A schematic diagram of a three-dimensional cross-sectional structure of a steam-water thermodynamic cycle system of a thermal power plant provided in one embodiment of the present application;

[0022] In the picture: Steam boiler-1;

[0023] Water pipe-11;

[0024] First connecting pipe-12;

[0025] Water pump - 111;

[0026] First one-way control valve-112;

[0027] Steam turbine-2;

[0028] Second connecting pipe-21;

[0029] The third one-way control valve-22;

[0030] Water filling tank - 3;

[0031] Water supply pipe - 31;

[0032] Second one-way control valve-32;

[0033] First control valve-311;

[0034] Heat exchange box-4;

[0035] Heat exchange tube-41;

[0036] Top cover - 42;

[0037] Drain pipe - 43;

[0038] Water storage tank - 44;

[0039] Electric control valve-431;

[0040] Circular ring piece - 414;

[0041] Water inlet pipe-411;

[0042] Outlet pipe-412;

[0043] Pump body - 413;

[0044] Water storage tanks - 5;

[0045] Airway return pipe - 6;

[0046] Air pump - 61;

[0047] Ring tube - 62;

[0048] Vent-621. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0050] It should be noted that in the description of the present application, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0051] The terms "installed", "connected" and "connected" in this application should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0052] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0053] This embodiment provides a steam-water thermal cycle system for a thermal power plant, see Figure 1-Figure 5 As shown, it includes a steam boiler 1, one side of the steam boiler 1 is connected to a water pipe 11, the other side of the steam boiler 1 is connected to the air inlet of the steam turbine 2 through a first connecting pipe 12, one end of the water pipe 11 is connected to the steam boiler 1, the other end of the water pipe 11 extends into the water injection box 3, a water pump 111 is provided at the port of the other end of the water pipe 11, one side of the water injection box 3 is connected to a water filling pipe 31, and the air outlet of the steam turbine 2 is connected to the second connecting pipe 12. The tube 21 is connected with the heat exchange box 4, and a heat exchange tube 41 is arranged at the bottom of the heat exchange box 4. The water inlet and the water outlet of the heat exchange tube 41 are respectively connected with the water storage tank 5 through the water inlet pipe 411 and the water outlet pipe 412. A pump body 413 is installed on the water inlet pipe 411. A top cover 42 is arranged on the upper part of the heat exchange box 4. The side of the top cover 42 is connected with one end of the return air pipe 6. The other end of the return air pipe 6 extends into the water injection tank 3. An air pump 61 is arranged on the return air pipe 6.

[0054] In the above embodiment, a water supply pipe 31 is connected to one side of the water injection tank 3, and soft water is injected into the water injection tank 3 through the water supply pipe 31. Soft water refers to water containing less dissolved minerals. During the heating process of the boiler, calcium, magnesium and other minerals in the water will precipitate to form scale and adhere to the inner wall of the boiler. These scales will reduce the heat conduction efficiency, causing the boiler to consume more energy to maintain the same heat output. The calcium and magnesium ion content in soft water is low. Using soft water can significantly reduce the formation of scale, thereby maintaining the efficient operation of the boiler. One end of the water delivery pipe 11 is connected to the steam boiler 1, and the other end of the water delivery pipe 11 extends into the water injection tank 3. A water pump 111 is provided at the port of the other end of the water delivery pipe 11. The soft water in the water injection tank 3 can be pumped into the steam boiler 1 through the water pump 111. After the steam boiler 1 heats and pressurizes the soft water, the high-temperature and high-pressure steam enters the steam turbine 2 through the first connecting pipe 12. After the steam enters the steam turbine 2, it will pass through the blades of the steam turbine 2. The steam expands between the blades, causing its pressure to decrease, and at the same time driving the blades to rotate. This process converts the thermal energy of the steam into mechanical energy. The rotation of the steam turbine 2 drives the generator or other mechanical equipment to work, and further converts the mechanical energy into electrical energy or other forms of energy. After the high-pressure steam is converted into low-pressure steam by the steam turbine 2, the outlet of the steam turbine 2 is connected to the heat exchange box 4 through the second connecting pipe 21. The low-pressure steam enters the heat exchange box 4 through the second connecting pipe 21. In the heat exchange box 4, part of the steam will release heat and liquefy and gather at the lower part of the heat exchange box 4. In this process, although the state of the steam has changed, the liquefied water still has temperature. For example, under normal pressure, the boiling point of water is 100°C. When the steam cools and begins to condense into water, the temperature will remain at 100°C, and the temperature of the liquid water will gradually decrease. A heat exchange tube 41 is provided at the bottom of the heat exchange box 4, and the water inlet and the water outlet of the heat exchange tube 41 are connected to the water storage tank 5 through the water inlet pipe 411 and the water outlet pipe 412 respectively, and a pump body 413 is installed on the water inlet pipe 411. In the preparation process of soft water, chemical agents such as phosphates are usually used to reduce the hardness of water, so soft water cannot be used directly. General water can be poured into the water storage tank 5, and the water in the water storage tank 5 is pressurized and injected into the heat exchange tube 41 through the pump body 413 installed on the water inlet pipe 411. The heat exchange tube 41 is used to exchange heat with the liquefied steam in the heat exchange box 4, which can avoid direct contact with the softened water in the heat exchange box 4, which is beneficial to improving the purity of the hot water. The hot water in the heat exchange tube 41 flows through the heat exchange tube 41 and then flows back to the water tank 5 through the outlet pipe 412. Such a reciprocating cycle can increase the water temperature in the water tank 5, especially in high-altitude and cold areas where hot water resources are relatively scarce. The hot water in the water tank 5 can be used for employees to keep warm or take a bath, thereby improving their living environment.In addition, hot water can be sold as a heat source to reduce the operating cost of the thermal power plant. In addition, the unliquefied steam is at the top of the heat exchange box 4. A top cover 42 is provided on the top of the heat exchange box 4. The side of the top cover 42 is connected to one end of the return air pipe 6. The other end of the return air pipe 6 extends into the water injection tank 3, and an air pump 61 is provided on the return air pipe 6. When the air pump 61 is turned on, the unliquefied steam at the top of the heat exchange box 4 can be extracted and then injected into the water injection tank 3 through the return air pipe 6. The steam in the return air pipe 6 contacts the injection water in the water injection tank 3 for heat exchange, which can increase the initial water temperature in the water injection tank 3, thereby reducing the fuel consumed by the steam boiler 1 for heating, so as to realize the recycling of steam heat, improve the steam utilization efficiency, and thereby reduce the fuel consumption of the thermal power plant during power generation, reduce the fuel cost of the enterprise, and thereby reduce the production cost, reduce greenhouse gas emissions and the release of other pollutants, which helps to achieve sustainable development goals and meet environmental protection requirements. Furthermore, the air pump 61 extracts the steam in the heat exchange box 4, which can reduce the air pressure in the heat exchange box 4. Under low pressure conditions, the saturated steam pressure is reduced, that is, at the same temperature, the steam is more likely to reach a saturated state, thereby promoting condensation. As the pressure is reduced, the kinetic energy of the steam molecules is reduced, making it easier for the steam to gather into liquid, thereby improving the heat exchange efficiency between the heat exchange tube 41 and the liquefied steam.

[0055] In one embodiment of the present application, see Figure 2 As shown, the water inlet of the water adding pipe 31 is arranged downward, and a first control valve 311 is installed at the water inlet of the water adding pipe 31 .

[0056] In the above embodiment, the tube body of the water adding pipe 31 is bent, so that the water adding port of the water adding pipe 31 is set downward. Compared with the water adding port being set upward, it can prevent dust and debris from settling into the tube mouth of the water adding pipe 31 and entering the water injection tank 3, causing pollution in the water injection tank 3. The accumulation of impurities can easily cause the boiler pipeline to be blocked, affecting the normal operation of the boiler. The first control valve 311 is used to close the first control valve 311 to prevent the water in the water injection tank 3 from flowing out of the water adding pipe 31.

[0057] In one embodiment of the present application, refer to Figure 5 As shown, a first one-way control valve 112 is provided at the connection between the water delivery pipe 11 and the steam boiler 1 .

[0058] In the above embodiment, the first one-way control valve 112 is a one-way conducting valve. There is pressurized steam in the steam boiler 1. If the water injection tank 3 is directly connected to the steam boiler 1 through the water pipe 11, the pressurized steam will flow back through the water pipe 11. On the one hand, it will impact the water pump 111 and cause damage to the water pump 111. On the other hand, the leakage of the pressurized steam in the steam boiler 1 will cause the steam boiler 1 to lose pressure and thus affect the energy conversion efficiency of the steam turbine 2. The first one-way control valve 112 is installed on the water pipe 11 to prevent the pressurized steam in the steam boiler 1 from flowing out of the water pipe 11.

[0059] In one embodiment of the present application, see Figure 2 As shown, the end of the return air pipe 6 extending into the water injection box 3 is connected to an annular tube 62 , and a plurality of vent holes 621 are formed on the upper end surface of the annular tube 62 .

[0060] In the above embodiment, the steam in the return air pipe 6 is pressurized by the air pump 61 and injected into the annular tube 62. A plurality of air vents 621 are provided on the upper end surface of the annular tube 62. The steam in the annular tube 62 emerges through the plurality of air vents 621 and contacts the soft water in the water injection tank 3 to exchange heat, thereby increasing the contact area between the soft water and the steam, improving the heat transfer efficiency, and making the soft water heated more evenly.

[0061] In one embodiment of the present application, see Figure 5 As shown, a second one-way control valve 32 is installed on the upper end surface of the water injection box 3.

[0062] In the above embodiment, after the steam and the gas in the heat exchange box 4 are injected into the water injection tank 3 through the return air pipe 6, the pressure in the water injection tank 3 will increase. The second one-way control valve 32 is used to release the air pressure in the water injection tank 3 to prevent the water injection tank 3 from being ruptured due to excessive pressure in the water injection tank 3.

[0063] In one embodiment of the present application, see Figure 5 As shown, a third one-way control valve 22 is provided at the connection between the second connecting pipe 21 and the heat exchange box 4 .

[0064] In the above embodiment, the third one-way control valve 22 installed on the second connecting pipe 21 plays a one-way conduction role on the second connecting pipe 21 to prevent the steam condensate in the heat exchange box 4 from flowing into the turbine 2 through the second connecting pipe 21, causing abnormal operation of the turbine 2.

[0065] In one embodiment of the present application, see Figure 1 As shown, the inner wall of the top cover 42 of the heat exchange box 4 is inclined.

[0066] In the above embodiment, the inner wall of the top cover 42 of the heat exchange box 4 is inclined, which plays a guiding role for the steam droplets condensed on the top cover 42 of the heat exchange box 4, so that the steam droplets flow down evenly along the inner wall of the heat exchange box 4, so as to prevent the steam droplets from gathering in certain areas, avoid local overcooling or overheating of the heat exchange box 4 due to excessive droplets, and improve the temperature stability in the heat exchange box 4.

[0067] In one embodiment of the present application, see Figure 4 As shown, the heat exchange tube 41 is arranged at the bottom of the heat exchange box 4 in a bent shape, and a circular ring sheet 414 is sleeved on the outer side of the tube body of the heat exchange tube 41 .

[0068] In the above embodiment, the heat exchange tube 41 is bent to increase the contact area of ​​heat exchange, thereby improving the heat exchange efficiency. The bent heat exchange tube 41 can better adapt to the thermal expansion caused by temperature changes, reduce the stress concentration caused by temperature difference, and thus extend the service life of the equipment. Furthermore, a circular ring sheet 414 is sleeved on the outer side of the tube body of the heat exchange tube 41. On the one hand, the circular ring sheet 414 can increase the surface area of ​​the heat exchange tube 41, thereby increasing the heat exchange area of ​​the heat exchange tube 41, which is beneficial to improving the heat exchange efficiency. On the other hand, the circular ring sheet 414 supports the heat exchange tube 41 to improve the stability of the heat exchange tube 41.

[0069] In one embodiment of the present application, the bottom end of the heat exchange box 4 is connected to a drain pipe 43, the drain pipe 43 is connected to a water storage tank 44, and an electric control valve 431 is installed on the drain pipe 43.

[0070] In the above embodiment, the drain pipe 43 connected to the bottom end of the heat exchange box 4 is connected to the water storage tank 5, which is used to discharge the steam liquefied water that has completed the heat exchange at the bottom of the heat exchange box 4. After the steam liquefied water is discharged, the electric control valve 431 is opened and flows into the water storage tank 44 through the drain pipe 43 for storage, which is convenient for later recycling. Optionally, the water storage tank 5 can be connected to the water injection tank 3 through a pipeline to facilitate the recycling of boiler soft water.

[0071] In one embodiment of the present application, the outer walls of the water injection tank 3 and the water storage tank 5 are covered with a thermal insulation layer.

[0072] In the above embodiment, the outer walls of the water injection tank 3 and the water storage tank 5 are covered with a heat preservation layer to prevent heat loss, thereby improving the heat circulation efficiency.

[0073] During the actual use of this application: open the first control valve 311 to inject soft water into the water injection tank 3, close the first control valve 311, open the first one-way control valve 112 to start the water pump 111 to inject the soft water in the water injection tank 3 into the steam boiler 1, and the first one-way control valve 112 is a one-way guide valve to prevent hot water or steam in the steam boiler 1 from flowing back into the water injection tank 3. To improve safety, the first one-way control valve 112 can be closed when the steam boiler 1 is running, and the high-pressure steam generated in the steam boiler 1 enters the steam turbine 2 through the first connecting pipe 12, converting the steam thermal energy into mechanical energy and then into electrical energy. The high-pressure steam becomes low-pressure steam after energy conversion by the steam turbine 2, and the low-pressure steam enters the heat exchange box 4 through the second connecting pipe 21. A third one-way control valve 22 is provided at the connection between the second connecting pipe 21 and the heat exchange box 4. The third one-way control valve 22 has a one-way conduction effect on the second connecting pipe 21 to prevent the steam condensate in the heat exchange box 4 from flowing into the steam turbine 2 through the second connecting pipe 21, causing abnormal operation of the steam turbine 2. Part of the steam in the heat exchange box 4 will release heat and liquefy and gather at the bottom of the heat exchange box 4. A heat exchange tube 41 is arranged at the bottom of the heat exchange box 4. The heat exchange tube 41 is bent to increase the contact area of ​​heat exchange, and achieve a larger heat exchange area under the limited space at the bottom of the heat exchange box 4. The bent shape can improve the overall structural strength of the heat exchange tube, making it more stable under high pressure or high temperature environment, and reducing the possibility of failure. The water inlet and outlet of the heat exchange tube 41 are connected to the water storage tank 5 through the water inlet pipe 411 and the water outlet pipe 412 respectively. The water in the water storage tank 5 is pressurized and injected into the heat exchange tube 41 through the pump body 413 installed on the water inlet pipe 411. The heat exchange tube 41 exchanges heat with the liquefied steam in the heat exchange box 4, which can avoid direct contact with the softened water in the heat exchange box 4 and improve the purity of the exchanged water. The unliquefied steam is at the top of the heat exchange box 4, and a top cover 42 is provided at the top of the heat exchange box 4. The inner wall of the top cover 42 of the heat exchange box 4 is inclined, which plays a role in guiding the steam droplets condensed on the top cover 42 of the heat exchange box 4, so that the steam droplets flow down evenly along the inner wall of the heat exchange box 4, so as to prevent the accumulation of steam droplets in certain areas, avoid the local overcooling or overheating of the heat exchange box 4 due to too many droplets, and improve the temperature stability in the heat exchange box 4. The side of the top cover 42 is connected to one end of the return air pipe 6, and the other end of the return air pipe 6 extends into the water injection box 3. The return air pipe 6 is provided with an air pump 61. When the air pump 61 is turned on, the unliquefied steam at the top of the heat exchange box 4 can be extracted and then injected into the water injection box 3 through the return air pipe 6. The steam in the return air pipe 6 contacts the injection water in the water injection box 3 for heat exchange, which can increase the initial water temperature in the water injection box 3, thereby reducing the fuel consumed by the steam boiler 1 for heating, so as to realize the recycling of steam heat.In addition, the drain pipe 43 connected to the bottom end of the heat exchange box 4 is connected to the water storage tank 5, and is used to discharge the steam liquefied water that has completed heat exchange at the bottom of the heat exchange box 4. A temperature detection device is installed at the bottom of the heat exchange box 4. The temperature detection device is electrically connected to the electric control valve 431 through a microprocessor. When the temperature at the bottom of the heat exchange box 4 is lower than the set value, the microprocessor controls the electric control 431 to open, so that the steam liquefied water is discharged and flows into the water storage tank 5 through the drain pipe 43 for storage, which is convenient for later recycling.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A steam-water thermal cycle system of a thermal power plant, characterized in that: The invention comprises a steam boiler (1), wherein one side of the steam boiler (1) is connected to a water pipe (11), and the other side of the steam boiler (1) is connected to the air inlet of a steam turbine (2) through a first connecting pipe (12), one end of the water pipe (11) is connected to the steam boiler (1), and the other end of the water pipe (11) extends into a water injection tank (3), a water pump (111) is arranged at the port of the other end of the water pipe (11), one side of the water injection tank (3) is connected to a water supply pipe (31), and the air outlet of the steam turbine (2) is connected to the steam boiler (1) through a second connecting pipe (21). The heat exchange box (4) is connected to the heat exchange box (4). A heat exchange pipe (41) is provided at the bottom of the heat exchange box (4). The water inlet and the water outlet of the heat exchange pipe (41) are connected to the water storage tank (5) through a water inlet pipe (411) and a water outlet pipe (412) respectively. A pump body (413) is installed on the water inlet pipe (411). A top cover (42) is provided on the top of the heat exchange box (4). The side of the top cover (42) is connected to one end of a return air pipe (6). The other end of the return air pipe (6) extends into the water injection box (3). An air pump (61) is provided on the return air pipe (6).

2. The steam-water thermal cycle system of a thermal power plant according to claim 1, characterized in that: The water inlet of the water adding pipe (31) is arranged downward, and a first control valve (311) is installed at the water inlet of the water adding pipe (31).

3. The steam-water thermal cycle system of a thermal power plant according to claim 1, characterized in that: A first one-way control valve (112) is provided at the connection between the water delivery pipe (11) and the steam boiler (1).

4. The steam-water thermal cycle system of a thermal power plant according to claim 1, characterized in that: An end of the return air pipe (6) extending into the water injection box (3) is connected to an annular pipe (62), and a plurality of ventilation holes (621) are provided on the upper end surface of the annular pipe (62).

5. The steam-water thermal cycle system of a thermal power plant according to claim 4, characterized in that: A second one-way control valve (32) is installed on the upper end surface of the water injection box (3).

6. The steam-water thermal cycle system of a thermal power plant according to claim 1, characterized in that: A third one-way control valve (22) is provided at the connection between the second connecting pipe (21) and the heat exchange box (4).

7. The steam-water thermal cycle system of a thermal power plant according to claim 1, characterized in that: The inner wall of the top cover (42) of the heat exchange box (4) is arranged to be inclined.

8. The steam-water thermal cycle system of a thermal power plant according to claim 7, characterized in that: The heat exchange tube (41) is arranged in a bent shape at the bottom of the heat exchange box (4), and a circular ring sheet (414) is sleeved on the outer side of the tube body of the heat exchange tube (41).

9. The steam-water thermal cycle system of a thermal power plant according to any one of claims 1 to 8, characterized in that: The bottom end of the heat exchange box (4) is connected to a drain pipe (43), the drain pipe (43) is connected to a water storage tank (44), and an electric control valve (431) is installed on the drain pipe (43).

10. The steam-water thermal cycle system of a thermal power plant according to any one of claims 1 to 8, characterized in that: The outer walls of the water injection tank (3) and the water storage tank (5) are coated with a thermal insulation layer.

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