Step heat supply unit system

Abstract

The cascade heat supply unit system comprises a first steam turbine, a second steam turbine, a first condenser, a first hot well, a second condenser, a second hot well, a first waste heat utilization pipeline, a second waste heat utilization pipeline and a self-flowing pipeline. According to the cascade heat supply unit system provided by the embodiment of the invention, the first condenser and the second condenser are used for carrying out gradient heating on the hot water, so that the utilization efficiency of heat energy can be further improved, the temperature of the hot water can be higher, and the heating effect can be further improved. Due to the fact that the back pressure of the first steam turbine is larger than that of the second steam turbine, the pressure of the first hot well is larger than that of the second hot well, condensate water in the first hot well can be supplied into the second hot well through pressure difference, the condensate water is output through the second hot well, and reuse of the condensate water can be achieved; the arrangement of drainage pumps and pipelines can be reduced, so that the system is simpler in structure and more energy-saving.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of waste heat in power plants, and in particular, to a cascaded heating unit system. Background Art

[0002] With the improvement of people's living standards, in the cold winter, especially in the northern regions, the demand for heating by the people is increasing continuously, resulting in an increase in the heating demand in our country, which will pose a huge challenge to the heating capacity of our country. For high efficiency and energy conservation, higher requirements are also put forward for the optimization of the power plant thermal system. In the current technology, the drain pumps are respectively configured for the drains of condensers and heaters at all levels of the power plant heat network, and after boosting the drain pressure, they are directly discharged into the hot well (condensate tank) of the last-stage condenser. The system is complex and energy-consuming, and the waste heat and residual pressure are not fully utilized. Summary of the Invention

[0003] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description section. This part of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0005] In view of this, the present application provides a cascaded heating unit system, including: A first steam turbine and a second steam turbine, the back pressure of the first steam turbine being greater than that of the second steam turbine; A first waste heat utilization pipeline, a first condenser and a first hot well, the first steam turbine, the first condenser and the first hot well being sequentially arranged on the first waste heat utilization pipeline; A second waste heat utilization pipeline, a second condenser and a second hot well, the second steam turbine, the second condenser and the second hot well being sequentially arranged on the second waste heat utilization pipeline; A gravity flow pipeline, the gravity flow pipeline connecting the first hot well and the second hot well; Wherein, the first condenser and the second condenser are used for gradient heating of the supply hot water.

[0006] In a feasible embodiment, the cascaded heating unit system further includes: A drain throttle valve, the drain throttle valve being arranged on the gravity flow pipeline.

[0007] In a feasible embodiment, the gravity flow pipeline is U-shaped, and the height of the connection of the gravity flow pipeline with the first hot well is lower than the height of the connection of the gravity flow pipeline with the second hot well.

[0008] In a feasible embodiment, the cascade heat supply unit system further includes: a heat network circulation pipeline, which first passes through the second condenser and then passes through the first condenser.

[0009] In a feasible embodiment, the cascade heat supply unit system further includes: a first bypass pipeline, which is connected to the heat network circulation pipeline and is in parallel with the first condenser; a second bypass pipeline, which is connected to the heat network circulation pipeline and is in parallel with the second condenser.

[0010] In a feasible embodiment, the cascade heat supply unit system further includes: a condensate pipe, one end of which is communicated with the second hot well.

[0011] In a feasible embodiment, the cascade heat supply unit system further includes: a drain cooler, the output end of the condensate pipe is communicated with the drain cooler; a third waste heat utilization pipeline, which is communicated with the drain cooler, and the third waste heat utilization pipeline is used for transporting the liquid output from the peak heater.

[0012] In a feasible embodiment, the cascade heat supply unit system further includes: a return water utilization pipeline, one end of which is communicated with the drain cooler and the other end is communicated with the first hot well, and is used for supplying the liquid output from the peak heater that has completed waste heat utilization to the first hot well.

[0013] In a feasible embodiment, the cascade heat supply unit system further includes: a drain pressure reducing valve group, which is arranged on the return water utilization pipeline and is arranged closer to the first hot well than the drain cooler.

[0014] In a feasible embodiment, the cascade heat supply unit system further includes: a third bypass pipeline, which is communicated with the third waste heat utilization pipeline and the return water utilization pipeline and is in parallel with the drain cooler.

[0015] Compared with the prior art, the present invention at least includes the following beneficial effects: The cascaded heat supply unit system provided by the embodiment of the present application includes a first steam turbine, a second steam turbine, a first condenser, a first hot well, a second condenser, a second hot well, a first waste heat utilization pipeline, a second waste heat utilization pipeline and a gravity flow pipeline. Based on this, in the working process, the first steam turbine converts the thermal energy of steam into mechanical energy, and then the used steam is supplied to the first condenser through the first waste heat utilization pipeline. After the steam exchanges heat at the first condenser, condensate is formed, and the condensate is transported to the first hot well through the first waste heat utilization pipeline again; the second steam turbine converts the thermal energy of steam into mechanical energy, and then the used steam is supplied to the second condenser through the second waste heat utilization pipeline. After the steam exchanges heat at the second condenser, condensate is formed, and the condensate is transported to the second hot well through the second waste heat utilization pipeline again. Through the settings of the first condenser and the second condenser, the utilization of waste heat is realized. And since the back pressure of the first steam turbine is greater than that of the second steam turbine, there will be a temperature difference in the condensing temperatures of the first condenser and the second condenser, which can achieve gradient heating and further improve the utilization efficiency of waste heat; because the back pressure of the first steam turbine is greater than that of the second steam turbine, the pressure of the first hot well is greater than that of the second hot well. The condensate in the first hot well can be supplied to the second heat energy by using the pressure difference, and the condensate is output through the second hot well again, so that the reuse of condensate can be realized. By means of gravity flow condensate, the setting of drain pumps and pipelines can be reduced, making the system structure simpler and more energy-saving. The cascaded heat supply unit system provided by the embodiment of the present application uses the first condenser and the second condenser to perform gradient heating on the hot water supply, which can further improve the utilization efficiency of thermal energy, can make the temperature of the heating water higher, and can further improve the heating effect of heating.

[0016] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically gives the specific implementation manners of the present invention. Brief Description of the Drawings

[0017] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 It is a schematic structural diagram of a cascaded heat supply unit system according to an embodiment provided by the present application.

[0018] Wherein, Figure 1 The corresponding relationship between the reference numerals in the drawings and the component names is: 110 First steam turbine, 120 second steam turbine, 130 first condenser, 140 first hot well, 150 second condenser, 160 second hot well, 170 drain cooler; 210 First waste heat utilization pipeline, 220 second waste heat utilization pipeline, 230 gravity flow pipeline, 240 heat network circulation pipeline, 250 first bypass pipeline, 260 second bypass pipeline, 270 condensate pipeline, 280 third waste heat utilization pipeline, 290 return water utilization pipeline, 2100 third bypass pipeline; 310 Drain throttle valve, 320 drain pressure reducing valve group. Specific embodiments

[0019] In the following description, numerous specific details are given in order to provide a more thorough understanding of the technical solutions provided by the present invention. However, it will be apparent to those skilled in the art that the technical solutions provided by the present invention may be implemented without one or more of these details.

[0020] It should be noted that the terms used herein are merely for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or combinations thereof.

[0021] Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited only to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present invention is thorough and complete, and the concepts of these exemplary embodiments are fully conveyed to those of ordinary skill in the art.

[0022] Considering that in the traditional technology, drain pumps and pipelines are respectively configured for the drains of condensers and heaters at all levels of the power plant heat network, the system is complex and energy consumption is high, the waste heat and residual pressure are not fully utilized, and when the drain water is discharged into the last-stage condenser, due to the sudden drop in pressure, the high-temperature drain water vaporizes, causing problems such as pipeline cavitation and vibration.

[0023] Such as Figure 1As shown in the figure, based on this, the present application proposes a cascaded heat supply unit system, including: a first steam turbine 110 and a second steam turbine 120, the pressure of the first steam turbine 110 is greater than the back pressure which is greater than that of the second steam turbine 120; a first waste heat utilization pipeline 210, a first condenser 130 and a first hot well 140, the first steam turbine 110, the first condenser 130 and the first hot well 140 are sequentially arranged on the first waste heat utilization pipeline 210; a second waste heat utilization pipeline 220, a second condenser 150 and a second hot well 160, the second steam turbine 120, the second condenser and the second hot well 160 are sequentially arranged on the second waste heat utilization pipeline 220; a gravity flow pipeline 230, the gravity flow pipeline 230 connects the first hot well 140 and the second hot well 160; wherein, the first condenser 130 and the second condenser 150 are used for gradient heating of the supply hot water.

[0024] The cascaded heat supply unit system provided by the embodiment of the present application includes a first steam turbine 110, a second steam turbine 120, a first condenser 130, a first hot well 140, a second condenser 150, a second hot well 160, a first waste heat utilization pipeline 210, a second waste heat utilization pipeline 220 and a gravity flow pipeline 230. Based on this, during the working process, the first steam turbine 110 converts the thermal energy of the steam into mechanical energy, and then the used steam is supplied to the first condenser 130 through the first waste heat utilization pipeline 210. After the steam completes heat exchange at the first condenser 130, it forms condensate, and the condensate is transported to the first hot well 140 through the first waste heat utilization pipeline 210 again; the second steam turbine 120 converts the thermal energy of the steam into mechanical energy, and then the used steam is supplied to the second condenser through the second waste heat utilization pipeline 220. After the steam completes heat exchange at the second condenser, it forms condensate, and the condensate is transported to the second hot well 160 through the second waste heat utilization pipeline 220 again. Through the settings of the first condenser 130 and the second condenser, the utilization of waste heat is realized. And since the back pressure of the first steam turbine 110 is greater than that of the second steam turbine 120, there will be a temperature difference in the condensing temperatures of the first condenser 130 and the second condenser, which can realize gradient heating and can further improve the utilization efficiency of waste heat; since the back pressure of the first steam turbine 110 is greater than that of the second steam turbine 120, the pressure of the first hot well 140 is greater than the pressure of the second hot well 160. The condensate in the first hot well 140 can be supplied to the second heat energy by using the pressure difference, and the condensate is output through the second hot well 160 again, which can realize the reuse of condensate. Through the gravity flow condensate, the setting of drain pumps and pipelines can be reduced, making the system structure simpler and more energy-saving.

[0025] For the cascaded heat supply unit system provided by the embodiment of the present application, the first condenser 130 and the second condenser 150 are used for gradient heating of the supply hot water, which can further improve the utilization efficiency of thermal energy, can make the temperature of the heating water higher, and can further improve the heating effect of heating.

[0026] As Figure 1 shown, in a feasible embodiment, the cascade heat supply unit system further includes: a drain throttle valve 310, and the drain throttle valve 310 is arranged on the gravity flow pipeline 230.

[0027] In this technical solution, a drain throttle valve 310 can be arranged on the gravity flow pipeline 230. By setting the drain throttle valve 310, the pipeline water resistance can be adjusted to adapt to the change of the back pressure of the low-pressure cylinder on the high and low pressure sides of the steam turbine, and the water levels of the first hot well 140 and the second hot well 160 of the condensers on the high and low pressure sides can be ensured to be stable. Specifically, the drain throttle valve 310 adopts an electric butterfly valve and can also serve as a pipeline isolation valve, further improving the system stability.

[0028] As Figure 1 shown, in a feasible embodiment, the gravity flow pipeline 230 is U-shaped, and the height of the connection between the gravity flow pipeline 230 and the first hot well 140 is lower than the height of the connection between the gravity flow pipeline 230 and the second hot well 160.

[0029] In this technical solution, the style of the gravity flow pipeline 230 is further provided. The gravity flow pipeline 230 can be U-shaped, and the height of the connection between the gravity flow pipeline 230 and the first hot well 140 is lower than the height of the connection between the gravity flow pipeline 230 and the second hot well 160. Based on this U-shaped design, the steam on the high-pressure side can be isolated, preventing the influence on the back pressure of the low-pressure side steam turbine in the case of poor sealing of the drain throttle valve 310, and at the same time ensuring the liquid level of the first hot well 140 on the high-pressure side. Furthermore, the stability of the system operation is ensured. Specifically, the U-shaped water seal height of the gravity flow pipeline 230 is set not less than the back pressure difference between the high and low pressure side low-pressure cylinders.

[0030] As Figure 1 shown, in a feasible embodiment, the cascade heat supply unit system further includes: a heat network circulation pipeline 240, and the heat network circulation pipeline 240 first passes through the second condenser and then passes through the first condenser 130.

[0031] In this technical solution, the cascade heat supply unit system can also include a heat network circulation pipeline 240. The water with a higher temperature in the heat network circulation pipeline 240 can be used for heating residents. Since the first condenser 130 corresponds to the first steam turbine 110 with a higher pressure, and the second condenser corresponds to the second steam turbine 120 with a lower pressure, the temperature in the second condenser is lower than that in the first condenser 130. The inlet water of the heat network circulation pipeline 240 first exchanges heat with the lower-temperature second condenser and then exchanges heat with the higher-temperature first condenser 130, which can make the water in the heat network circulation pipeline 240 increase in temperature in a gradient manner, with higher heat energy utilization efficiency, and the water output from the heat network circulation pipeline 240 can better heat residents.

[0032] As Figure 1 shown, in a feasible implementation, the cascade heat supply unit system further includes: a first bypass pipeline 250, the first bypass pipeline 250 is connected to the heat network circulation pipeline 240 and is in parallel with the first condenser 130; a second bypass pipeline 260, the second bypass pipeline 260 is connected to the heat network circulation pipeline 240 and is in parallel with the second condenser.

[0033] In this technical solution, the cascade heat supply unit system may further include a first bypass pipeline 250 and a second bypass pipeline 260. Through the setting of the first bypass pipeline 250, the heat network circulation pipeline 240 may not flow through the first condenser 130. Through the setting of the second bypass pipeline 260, the heat network circulation pipeline 240 may not flow through the second condenser. In the case where the liquid heat exchange in the heat network circulation pipeline 240 reaches the target temperature, the waste of thermal energy can be avoided.

[0034] As Figure 1 shown, in a feasible implementation, the cascade heat supply unit system further includes: a condensate pipe 270, and one end of the condensate pipe 270 communicates with the second hot well 160.

[0035] In this technical solution, the cascade heat supply unit system further includes a condensate pipe 270. The first hot well 140 is used to collect the condensate output by the first condenser 130, and the second hot well 160 is used to collect the condensate output by the second condenser 150. The condensate in the first hot well 140 can be transported to the second hot well 160 by using the pressure difference. The second hot well 160 can output the condensate through the condensate pipe 270 to realize the recycling of the condensate and be more energy-saving.

[0036] As Figure 1 shown, in a feasible implementation, the cascade heat supply unit system further includes: a drain cooler 170, the output end of the condensate pipe 270 communicates with the drain cooler 170; a third waste heat utilization pipeline 280, the third waste heat utilization pipeline is connected to the drain cooler 170, and the third waste heat utilization pipeline 280 is used to transport the liquid output by the peak heater.

[0037] In this technical solution, the cascade heat supply unit system may further include a drain cooler 170 and a third waste heat utilization pipeline 280. The liquid with a higher temperature at the output end of the peak heater can be supplied into the drain cooler 170. The condensate pipe 270 is then connected to the drain cooler 170. The high-temperature liquid output from the peak heater can exchange heat with the liquid output via the condensate pipe 270 in the drain cooler 170, which can increase the temperature of the condensate water, raise the initial temperature of the condensate water, facilitate the re-formation of high-temperature steam from the condensate water for use by the first steam turbine 110 and the second steam turbine 120, utilize the waste heat of the liquid output from the peak heater, further improve the thermal energy utilization efficiency, reduce energy consumption, and be more energy-saving.

[0038] As Figure 1 shown, in a feasible implementation, the cascade heat supply unit system further includes a return water utilization pipeline 290. One end of the return water utilization pipeline 290 is connected to the drain cooler 170, and the other end is connected to the first hot well 140, for supplying the liquid output from the peak heater that has completed waste heat utilization to the first hot well 140.

[0039] In this technical solution, the cascade heat supply unit system may further include a return water utilization pipeline 290. One end of the return water utilization pipeline 290 is connected to the drain cooler 170, and the other end is connected to the first hot well 140. After the high-temperature liquid output from the peak heater completes heat exchange in the drain cooler 170, it can be supplied into the first hot well 140 via the return water utilization pipeline 290, then flow by gravity to the second hot well 160, and be reused through the condensate pipe 270, which can further improve the resource reuse rate.

[0040] As Figure 1 shown, in a feasible implementation, the cascade heat supply unit system further includes a drain pressure reducing valve group 320. The drain pressure reducing valve group 320 is arranged on the return water utilization pipeline 290 and is arranged closer to the first hot well 140 than the drain cooler 170.

[0041] In this technical solution, the structural composition of the cascade heat supply unit system is further provided. The cascade heat supply unit system may further include a drain pressure reducing valve group 320 arranged on the return water utilization pipeline 290. By setting the drain pressure reducing valve group 320 and adjusting the opening degree of the drain pressure reducing valve group 320, the pressure of the drain pipeline before the valve can be maintained, preventing vibration or damage to the return water utilization pipeline 290, and effectively reducing the cavitation risk of the return water utilization pipeline 290.

[0042] In this technical solution, the hydrophobic pressure reducing valve group 320 is arranged closer to the first hot well 140 than the hydrophobic cooler 170. With this arrangement, the length of the gas-liquid two-phase flow can be shortened, avoiding problems such as cavitation and vibration in the pipeline, and further ensuring the stability of the system operation.

[0043] As Figure 1 shown, in a feasible implementation manner, the cascade heating unit system further includes: a third bypass pipeline 2100, which is connected to the third waste heat utilization pipeline 280 and the return water utilization pipeline 290 and is in parallel with the hydrophobic cooler 170.

[0044] In this technical solution, the cascade heating unit system may further include a third bypass pipeline 2100. When the temperature of the liquid output by the peak heater is relatively low, the liquid output by the peak heater can be directly supplied to the first hot well 140 for reuse through the third waste heat utilization pipeline 280 and the return water utilization pipeline 290.

[0045] In the present invention, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plural" means two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected to", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0047] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0048] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A stepped heat supply unit system, characterized in that, Comprising: A first steam turbine and a second steam turbine, wherein the back pressure of the first steam turbine is greater than that of the second steam turbine; A first waste heat utilization pipeline, a first condenser and a first hot well, and the first steam turbine, the first condenser and the first hot well are sequentially arranged on the first waste heat utilization pipeline; A second waste heat utilization pipeline, a second condenser and a second hot well, and the second steam turbine, the second condenser and the second hot well are sequentially arranged on the second waste heat utilization pipeline; A gravity flow pipeline that connects the first hot well and the second hot well; Wherein, the first condenser and the second condenser are used for gradient heating of the supply hot water.

2. The stepped heat supply unit system according to claim 1, wherein Further comprising: A throttle valve for draining steam, and the throttle valve for draining steam is arranged on the gravity flow pipeline.

3. The cascade heating unit system according to claim 1, wherein The gravity flow pipeline is U-shaped, and the height of the connection of the gravity flow pipeline with the first hot well is lower than the height of the connection of the gravity flow pipeline with the second hot well.

4. The stepped heat supply unit system according to claim 1, characterized in that, Further comprising: A heat network circulation pipeline that first passes through the second condenser and then passes through the first condenser.

5. The stepped heat supply unit system according to claim 4, characterized in that, Further comprising: A first bypass pipeline that is connected to the heat network circulation pipeline and is in parallel with the first condenser; A second bypass pipeline that is connected to the heat network circulation pipeline and is in parallel with the second condenser.

6. The stepped heat supply unit system according to any one of claims 1 to 5, characterized in that, Further comprising: A condensate pipeline, and one end of the condensate pipeline is communicated with the second hot well.

7. The cascade heat supply unit system according to claim 6, characterized in that, Further comprising: A drain cooler, and the output end of the condensate pipeline is communicated with the drain cooler; A third waste heat utilization pipeline that is communicated with the drain cooler, and the third waste heat utilization pipeline is used for conveying the liquid output by the peak heater.

8. The step heating unit system according to claim 7, characterized in that, Further comprising: A return water utilization pipeline, one end of the return water utilization pipeline is communicated with the drain cooler, and the other end is communicated with the first hot well, and is used for supplying the liquid output by the peak heater that has completed waste heat utilization to the first hot well.

9. The cascade heat supply unit system according to claim 8, wherein, Further comprising: A steam drain pressure reducing valve group that is arranged on the return water utilization pipeline and is arranged closer to the first hot well than the drain cooler.

10. The cascade heat supply unit system according to claim 8, characterized in that, Further comprising: A third bypass pipeline that is communicated with the third waste heat utilization pipeline and the return water utilization pipeline and is in parallel with the drain cooler.

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