Flue gas waste heat utilization system for heating chemical water in thermal power plant

Abstract

The utility model relates to a flue gas waste heat utilization system for heating chemical water in a thermal power plant. The system comprises a flue gas waste heat recovery mechanism, a flue gas loop and a chemical water generation loop, the flue gas waste heat recovery mechanism comprises a flue gas heat exchange pipe and a water heat exchange pipe, and flue gas in the flue gas heat exchange pipe can heat water in the water heat exchange pipe; the flue gas loop comprises a first flue gas pipeline and a second flue gas pipeline which are communicated with the two ends of the flue gas heat exchange pipe, so that flue gas circulates between the flue gas heat exchange pipe and the main flue gas pipeline; the chemical water generating loop comprises a first water conveying pipeline and a second water conveying pipeline which communicate with the two ends of the water heat exchange pipe, the first water conveying pipeline or the second water conveying pipeline conveys water to the water heat exchange pipe, and the other water conveying pipeline outputs heated water to the raw water heater. Flue gas and chemical water are input into the flue gas heat exchange pipe and the water heat exchange pipe respectively for heat exchange, so that the chemical water absorbs waste heat of the flue gas and then is conveyed to the raw water heater for heating. Not only is effective utilization of low-grade energy achieved, but also waste of high-grade energy is reduced.

Description

Technical Field

[0001] The present application relates to the field of energy-saving and emission-reduction technologies for power plants, and in particular to a flue gas waste heat utilization system for chemical water heating in thermal power plants. Background Art

[0002] With the rapid development of social economy, the demand for electricity has also increased. In order to meet the needs of social and economic development and the improvement of people's living standards, a large number of power plants have been built. Among them, thermal power plants, especially coal-fired electrochemical power plants, account for a large proportion of my country's energy supply. In addition, thermal power plants have a large number of chemical water treatment requirements. In the chemical water treatment process, the water output of reverse osmosis is related to the water temperature. Therefore, when the water temperature is low, the raw water needs to be heated before reverse osmosis treatment can be performed.

[0003] In the related technology, medium-pressure steam is usually drawn out from the compressor cylinder of the steam turbine to heat the chemical water. Especially in winter in northern my country, the initial temperature of chemical water is low and the required amount of water replenishment is large. When using it, the temperature of chemical water needs to be heated from 4℃~8℃ to about 25℃, which not only wastes the energy of high-grade steam for power generation, but also discharges most of the heat to the environment through the condenser circulating cooling water, resulting in large steam loss and greatly reducing the economic operation of the unit.

[0004] In the context of energy conservation and carbon reduction, how to fully recycle low-grade energy for heating chemical wastewater, realize the cascade utilization of energy, avoid the conventional use of high-grade steam heating, improve the thermal economy of the unit, and achieve environmental protection and energy-saving effects is the current work problem facing power plants. Utility Model Content

[0005] Based on this, it is necessary to provide a flue gas waste heat utilization system for heating chemical water in a thermal power plant to address the above-mentioned problem of using high-grade energy to heat chemical water, resulting in waste of steam energy and affecting the economic operation of the unit.

[0006] A flue gas waste heat utilization system for heating chemical water in a thermal power plant, comprising a flue gas waste heat recovery mechanism, a flue gas circuit and a chemical water circuit, wherein the flue gas waste heat recovery mechanism comprises a flue gas heat exchange pipe and a water heat exchange pipe, wherein the flue gas heat exchange pipe is configured to be mutually overlapped or at least partially in contact with the water heat exchange pipe, so that the flue gas in the flue gas heat exchange pipe can heat the chemical water in the water heat exchange pipe; the flue gas circuit comprises a first flue gas duct and a second flue gas duct, wherein the flue gas heat exchange pipe is connected between the first flue gas duct and the second flue gas duct, and the first flue gas duct and the second flue gas duct are away from the flue gas One end of the heat exchange tube is used to connect to the main smoke duct; any one of the first smoke duct and the second smoke duct is used to transport the smoke in the main smoke duct to the smoke heat exchange tube, and the other is used to transport the smoke after heat exchange in the smoke heat exchange tube back to the main smoke duct; the chemical water production circuit includes a first water supply pipe and a second water supply pipe, the water heat exchange pipe is connected between the first water supply pipe and the second water supply pipe, any one of the first water supply pipe and the second water supply pipe is used to transport chemical water production to the water heat exchange pipe, and the other is used to output the heated chemical water production to the raw water heater.

[0007] In one of the embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes a flushing mechanism, which includes a spray component and a flushing pipe connected to the spray component, the spray component is installed on the water heat exchange tube, and the flushing pipe is used to supply water to the spray component to clean the water heat exchange tube.

[0008] In one of the embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes a monitoring mechanism, which includes a temperature monitoring component and a pressure monitoring component installed in the flue gas circuit and / or the chemical water heating circuit and / or the flushing mechanism; wherein the temperature monitoring component is used to monitor the real-time temperature of the flue gas circuit and / or the chemical water heating circuit to generate a temperature signal; and the pressure monitoring component is used to monitor the real-time pressure of water in the chemical water heating circuit and / or the flushing pipe to generate a pressure signal.

[0009] In one embodiment, the temperature monitoring assembly includes a first temperature measuring element, a second temperature measuring element, a third temperature measuring element and a fourth temperature measuring element arranged at intervals, the first temperature measuring element is installed on the first water pipeline, the second temperature measuring element is installed on the second water pipeline, the third temperature measuring element is installed on the first flue gas pipeline, and the fourth temperature measuring element is installed on the second flue gas pipeline; wherein the first temperature measuring element is used to monitor the temperature of chemical wastewater in the first water pipeline, the second temperature measuring element is used to monitor the temperature of chemical wastewater in the second water pipeline, the third temperature measuring element is used to monitor the temperature of flue gas in the first flue gas pipeline, and the fourth temperature measuring element is used to monitor the temperature of flue gas in the second flue gas pipeline, so as to obtain the temperature signal.

[0010] In one embodiment, the pressure monitoring assembly includes a first pressure measuring member, a second pressure measuring member and a third pressure measuring member arranged at intervals, the first pressure measuring member is installed in the first water pipeline to monitor the water pressure inside the first water pipeline, the second pressure measuring member is installed in the second water pipeline to monitor the water pressure inside the second water pipeline, and the third pressure measuring member is installed in the flushing pipeline to monitor the water pressure inside the flushing pipeline, thereby obtaining the pressure signal.

[0011] In one of the embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes an opening control mechanism, and the opening control mechanism can be signal-connected with the monitoring mechanism; the opening control mechanism includes a first opening valve installed in the first flue gas duct and a second opening valve installed in the second flue gas duct.

[0012] In one embodiment, the first opening valve and / or the second opening valve includes a plurality of different opening positions, and the first opening valve and / or the second opening valve can be switched to the corresponding opening position according to the temperature signal to achieve regulation of the flue gas flow rate in the flue gas circuit.

[0013] In one embodiment, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes a drainage mechanism, which is installed in the flue gas circuit to allow the flue gas to flow from the first flue gas duct through the flue gas heat exchange tube to flow into the second flue gas duct, or to allow the flue gas to flow from the second flue gas duct through the flue gas heat exchange tube to flow into the first flue gas duct.

[0014] In one embodiment, the flue gas temperature in the first flue gas duct is controlled at 120°C to 160°C, and the flue gas temperature in the second flue gas duct is controlled at less than 60°C.

[0015] In one embodiment, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes a condensate discharge mechanism connected to the flue gas waste heat recovery mechanism, and the condensate discharge mechanism includes a condensate input pipe and a water storage member. The condensate input pipe is connected between the flue gas waste heat recovery mechanism and the water storage member to discharge condensate from the flue gas waste heat recovery mechanism to the water storage member for storage.

[0016] In one of the embodiments, the condensate discharge mechanism further includes a condensate output pipe and a driving member, wherein the condensate output pipe is connected to the water storage member, and the driving member is installed on the condensate output pipe to drive the condensate to be discharged from the water storage member.

[0017] In one of the embodiments, the condensate discharge mechanism further includes a dosing component connected to the condensate output pipe. Driven by the driving member, the condensate can flow through the dosing component, and the dosing component is used to neutralize the pH value of the condensate flowing through.

[0018] In one embodiment, the condensate discharge mechanism further includes a liquid level monitoring component, which is installed on the water storage component and monitors the water level inside the water storage component. The liquid level monitoring component can be connected to the driving component by signal.

[0019] The above-mentioned flue gas waste heat utilization system for chemical water heating in thermal power plants, by respectively inputting flue gas and chemical water into flue gas heat exchange tubes and water heat exchange tubes for heat exchange operation, allows the chemical water to absorb the residual heat of the flue gas and then be transported to the raw water heater. This not only realizes the effective utilization of low-grade energy and reduces the waste of high-grade energy, but also increases the initial temperature of the chemical water transported to the raw water heater, reduces the heat energy required for heating, and thus realizes the cascade utilization of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a flue gas waste heat utilization system for chemical water heating in a thermal power plant in one embodiment of the present application.

[0021] Figure 2 This is a structural schematic diagram of a flue gas waste heat utilization system for chemical water heating in a thermal power plant in one embodiment of the present application.

[0022] Notes on the attached drawings:

[0023] 1. Flue gas waste heat recovery mechanism; 11. Flue gas heat exchange pipe; 12. Water heat exchange pipe; 2. Flue gas circuit; 21. First flue gas pipeline; 22. Second flue gas pipeline; 3. Chemical water circuit; 31. First water pipeline; 32. Second water pipeline; 4. Flushing mechanism; 41. Spraying element; 42. Flushing pipeline; 511. First temperature measuring element; 512. Second temperature measuring element; 513. Third temperature measuring element; 514. Fourth temperature measuring element; 521. First pressure measuring element; 522. Second pressure measuring element; 523. Third pressure measuring element; 53. Heat meter; 54. Water meter; 61. First opening valve; 62. Two-opening valve; 7. Drainage mechanism; 8. Condensate discharge mechanism; 81. Condensate input pipe; 82. Water storage component; 83. Condensate output pipe; 84. Driving component; 85. Dosing component; 86. Liquid level monitoring component; 9. Main flue gas duct; A. First inlet end; B. First outlet end; C. Second outlet end; D. Second inlet end; E. Third outlet end; F. Fourth outlet end; G. Third inlet end; H. Fifth outlet end; I. Fourth inlet end; J. Sixth outlet end; K. Seventh outlet end; M. Eighth outlet end; N. Fifth inlet end; O. Ninth outlet end; P. Tenth outlet end. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0025] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does 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.

[0026] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0028] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0030] With the rapid development of social economy, the demand for electricity has also increased. In order to meet the needs of social and economic development and the improvement of people's living standards, a large number of power plants have been built. Among them, thermal power plants, especially coal-fired electrochemical power plants, account for a large proportion of my country's energy supply. In addition, thermal power plants have a large number of chemical water treatment requirements. In the chemical water treatment process, the water output of reverse osmosis is related to the water temperature. Therefore, when the water temperature is low, the raw water needs to be heated before reverse osmosis treatment can be performed.

[0031] In thermal power plants, the exhaust gas temperature of coal-fired boilers can usually reach 130°C. The flue gas contains a lot of latent heat of vaporization, which is often directly discharged into the atmosphere with the flue gas, resulting in waste of flue gas heat. If the flue gas temperature can be reduced to below the acid dew point and this part of the latent heat of vaporization can be recovered, it will play an important role in saving fuel consumption.

[0032] Traditional thermal power plants usually heat chemical water by extracting medium-pressure steam from the medium-pressure cylinder of the steam turbine. This not only wastes high-quality steam energy for power generation, but also discharges part of the heat (about 55%) into the environment through the condenser circulating cooling water.

[0033] Especially in winter in northern my country, the initial temperature of chemical water is low and the required amount of water replenishment is large. When in use, the temperature of chemical water needs to be heated from 4℃~8℃ to about 25℃, which causes large steam loss and greatly reduces the economic operation of the unit. In the context of energy conservation and carbon reduction, how to fully recycle low-grade energy for heating chemical water, realize the cascade utilization of energy, avoid the conventional use of high-grade steam heating, improve the thermal economy of the unit, and achieve environmental protection and energy saving effects, this is the working problem currently faced by power plants.

[0034] In order to overcome the above-mentioned problem of using high-grade energy to heat chemical water, resulting in waste of steam energy and affecting the economic operation of the unit, the present application provides a flue gas waste heat utilization system for heating chemical water in a deep thermal power plant for heating chemical water in a coal-fired power plant. The system uses low-grade deep flue gas waste heat to heat chemical water, and while ensuring the outlet temperature of the chemical water, it realizes the cascade utilization of energy and avoids the conventional use of high-grade steam heating, thereby improving the economy of the unit, which is both environmentally friendly and energy-saving.

[0035] The following is combined with Figure 1-2 The embodiments of the present application are described in further detail.

[0036] See also Figure 1 , Figure 1The schematic diagram of the flue gas waste heat utilization system for chemical water production heating in a thermal power plant in one embodiment of the present application is shown. The present application provides a flue gas waste heat utilization system for chemical water production heating in a thermal power plant in one embodiment, specifically a flue gas waste heat recovery and utilization system used in a coal-fired power plant, the flue gas waste heat utilization system for chemical water production heating in a thermal power plant includes a flue gas waste heat recovery mechanism 1, a flue gas circuit 2 and a chemical water production circuit 3. Among them, the flue gas circuit 2 is used for flue gas circulation, and the chemical water production circuit 3 is used to transmit chemical water production to a raw water heater for subsequent heating operations.

[0037] In the embodiment of the present application, both the flue gas circuit 2 and the chemical water-generating circuit 3 can pass through the flue gas waste heat recovery mechanism 1 and complete the heat exchange operation in the flue gas waste heat recovery mechanism 1, so that the chemical water-generating can absorb the residual temperature of the flue gas and increase the initial temperature, thereby reducing the energy consumption generated by the raw water heater to heat the chemical water-generating.

[0038] Continue reading Figure 1 As shown, the flue gas waste heat recovery mechanism 1 includes a flue gas heat exchange tube 11 and a water heat exchange tube 12. The flue gas heat exchange tube 11 is used for the flow of flue gas discharged from the coal-fired boiler, and the water heat exchange tube 12 is used for the flow of chemical water. The flue gas heat exchange tube 11 and the water heat exchange tube 12 are mutually overlapped or at least partially in contact with each other to achieve contact heat exchange. Specifically, during the flow of flue gas and chemical water, the chemical water with a lower temperature continuously absorbs the heat of the flue gas with a higher temperature to increase its own temperature, thereby reducing the energy demand for the subsequent raw water heater.

[0039] In the present application, see Figure 1 As shown, only the flue gas heat exchange tube 11 is sleeved on the periphery of the water heat exchange tube 12. It is understandable that in some other embodiments, the water heat exchange tube 12 may be sleeved on the periphery of the flue gas heat exchange tube 11, or the outer side walls of the flue gas heat exchange tube 11 and the water heat exchange tube 12 may be attached to each other to achieve heat transfer.

[0040] Specifically, the flue gas circuit 2 includes a first flue gas duct 21 and a second flue gas duct 22, and the above-mentioned flue gas heat exchange pipe 11 is connected between the first flue gas duct 21 and the second flue gas duct 22. The first flue gas duct 21, the second flue gas duct 22 and the end of the second flue gas duct 22 away from the flue gas heat exchange pipe 11 are respectively connected to the main flue gas duct 9 to realize the circulation heat exchange and recovery of the flue gas residual temperature.

[0041] In addition, in order to realize the circulation of flue gas between the flue gas circuit 2, the flue gas heat exchange pipe 11 and the main flue gas duct 9, in some embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant further includes a drainage mechanism 7 installed in the flue gas circuit 2. In the embodiment of the present application, the drainage mechanism 7 can specifically be an electric axial flow induced draft fan, which plays a role in guiding the actual flow direction of the flue gas.

[0042] During the actual operation of the flue gas waste heat utilization system for chemical water heating in a thermal power plant, the flue gas can flow out from the main flue gas duct 9 under the drainage action of the drainage mechanism 7 according to the actual flow direction requirements, and pass through the first flue gas duct 21, the flue gas heat exchange tube 11 and the second flue gas duct 22 in sequence and then be returned to the main flue gas duct 9; it can also flow out from the main flue gas duct 9 according to the actual flow direction requirements, and pass through the second flue gas duct 22, the flue gas heat exchange tube 11 and the first flue gas duct 21 in sequence and then be returned to the main flue gas duct 9, thereby adapting to the actual operation requirements of the flue gas waste heat utilization system for chemical water heating in a thermal power plant.

[0043] In the embodiment of the present application, the flue gas circuit 2 is mainly arranged on the main flue gas duct 9 with a flue gas temperature higher than 120°C and lower than 160°C. The flue gas in the main flue gas duct 9 first flows into the first flue gas duct 21 through the first inlet end A of the first flue gas duct 21, and then enters the flue gas heat exchange tube 11 through the first outlet end B of the first flue gas duct 21 for heat exchange operation. The flue gas that absorbs part of the residual heat is then input into the second flue gas duct 22 through the third inlet end G of the second flue gas duct 22, and is returned to the main flue gas duct 9 from the fifth outlet end H of the second flue gas duct 22 along the second flue gas duct 22, completing a cycle of heat exchange.

[0044] In the embodiment of the present application, the flue gas waste heat utilization system for heating chemical water in a thermal power plant adopts the method shown above to circulate the flue gas. On the one hand, it is convenient for the chemical water to absorb the flue gas waste heat and increase the initial temperature of the chemical water; on the other hand, it also reduces the temperature of the exhausted flue gas, so that the flue gas temperature is reduced to below the acid dew point corrosion temperature (less than 60°C), thereby having certain environmental protection and flue gas demisting functions; on the other hand, with the help of chemical water to absorb the flue gas waste heat, it also plays a certain role in the whitening of flue gas in the northern region, and has the dual effects of energy saving and environmental protection.

[0045] It is understandable that in some other embodiments, the flue gas can also be configured to be input from the second flue gas channel to the flue gas heat exchange tube 11, and then returned to the main flue gas duct 9 through the first flue gas channel. As long as the heat absorption function of the flue gas can be achieved, the specific flow direction of the flue gas is not limited in this application. However, in comparison, the flow direction of the flue gas in the flue gas circuit 2 is consistent with the flow direction of the flue gas in the main flue gas duct 9, which is more conducive to achieving the cooling operation of the flue gas and can improve energy saving and environmental protection effects.

[0046] Continue reading Figure 1As shown, in some embodiments, in order to improve the heat exchange effect between flue gas and chemical water in the flue gas waste heat recovery mechanism 1, the structure of the water heat exchange tube 12 is specially designed. In the embodiment of the present application, the water heat exchange tube 12 is configured as a "broken line" structure to extend the transmission time of chemical water in the water heat exchange tube 12, thereby extending the heat exchange time between the flue gas and the flue gas, and improving the heat exchange effect.

[0047] In addition, the chemical raw water circuit 3 specifically includes a first water supply pipe 31 and a second water supply pipe 32. The above-mentioned water heat exchange pipe 12 is connected between the first water supply pipe 31 and the second water supply pipe 32. Any one of the first water supply pipe 31 and the second water supply pipe 32 can be used to transport chemical raw water to the water heat exchange pipe 12, and the other is used to transport the chemical raw water heated by the flue gas waste heat to the raw water heater for further heating treatment.

[0048] In the present application, see Figure 1 As shown, only the example of chemically generated water flowing from the first water pipeline 31 through the water heat exchange tube 12 and then into the second water pipeline is described. It can be understood that in some other embodiments, it can also be arranged according to the actual site so that chemically generated water flows from the second water pipeline 32 through the water heat exchange tube 12 and then into the first water pipeline 31.

[0049] During the actual operation of the flue gas waste heat utilization system for heating chemical raw water in a thermal power plant, the chemical raw water flows into the water heat exchange tube 12 from the third outlet end E of the first water pipeline 31. After heat exchange treatment, the heated chemical raw water flows into the second water pipeline 32 from the second inlet end D of the second water pipeline 32, and is transported to the raw water heater by means of the second water pipeline 32, so as to further heat the heated chemical raw water.

[0050] In the embodiment of the present application, the above technical solution is used to preheat the low-temperature chemical raw water, and the steam from the intermediate pressure cylinder of the steam turbine is not used to heat the chemical raw water. The saved steam can continue to expand and do work in the steam turbine, thereby improving the thermal efficiency of the unit. In addition, the present application can also effectively reduce the heat exchange temperature difference at the inlet and outlet ends of the raw water heater during the subsequent heating process, effectively utilize the heat of the latent heat of low-grade flue gas to heat the chemical raw water, avoid the waste of high-grade energy (such as steam), save high-grade energy, thereby further reducing the irreversible loss of high-grade energy, and realizing the cascade utilization of energy.

[0051] Combination Figure 2 As shown, Figure 2The schematic diagram of the structure of the flue gas waste heat utilization system for chemical water heating in a thermal power plant in one embodiment of the present application is shown. In some embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant further includes a flushing mechanism 4, which includes a spray part 41 installed in the flue gas waste heat recovery mechanism 1 and a flushing pipe 42 connected between the spray part 41 and the external water source. After the heat exchange operation is completed, the external water source can flow into the spray part 41 from the second outlet end C of the flushing pipe 42, so that the external water source flushes the water heat exchange tube 12 through the spray part 41 to remove the dust on its internal surface, and at the same time plays an anti-corrosion role, which can effectively extend the service life of the water heat exchange tube 12.

[0052] In some embodiments, the flue gas waste heat utilization system for chemical water generation heating in a thermal power plant further includes a monitoring mechanism, which includes a temperature monitoring component and a pressure monitoring component installed in the flue gas loop 2 and / or the chemical water generation loop 3 and / or the flushing mechanism 4. Among them, the temperature monitoring component is used to monitor the real-time temperature of the flue gas loop 2 and / or the chemical water generation loop 3 to generate a corresponding temperature signal, and adjust the heat exchange efficiency of the flue gas waste heat utilization system for chemical water generation heating in a thermal power plant accordingly according to the temperature signal. The pressure monitoring component is used to monitor the actual pressure in the chemical water generation loop 3 and / or the flushing pipeline 42 to generate a corresponding pressure signal, which, on the one hand, makes the flow rate of chemical water generation and the heat exchange efficiency compatible, and on the other hand, can also improve the operational safety of the flue gas waste heat utilization system for chemical water generation heating in a thermal power plant.

[0053] In the embodiment of the present application, there are four temperature monitoring components, namely a first temperature measuring component 511 installed on the first water pipe 31, a second temperature measuring component 512 installed on the second water pipe 32, a third temperature measuring component 513 installed on the first flue gas duct 21, and a fourth temperature measuring component 514 installed on the second flue gas duct 22.

[0054] The first temperature measuring element 511 and the second temperature measuring element 512 are used to monitor the temperature of the chemical water in the first water pipe 31 and the second water pipe 32, respectively, so as to obtain the temperature difference value before and after the chemical water heat exchange, and the third temperature measuring element 513 and the fourth temperature measuring element 514 are installed in the first flue gas pipe 21 and the second flue gas pipe 22, respectively, so as to obtain the temperature difference value before and after the flue gas heat exchange. The above-mentioned temperature signal can be obtained by combining the temperature difference value before and after the chemical water heat exchange and the temperature difference value before and after the flue gas heat exchange.

[0055] In the embodiment of the present application, there are three pressure monitoring components, namely, a first pressure measuring piece 521 installed on the first water pipeline 31, a second pressure measuring piece 522 installed on the second water pipeline 32, and a third pressure measuring piece 523 installed on the flushing pipeline 42. The first pressure measuring piece 521, the second pressure measuring piece 522 and the third pressure measuring piece 523 are used to monitor the water pressure inside the first water pipeline 31, the second water pipeline 32 and the flushing pipeline 42, respectively, so as to obtain the above-mentioned pressure signal. In actual operation, the operator can judge whether the supply rate of chemical water in the flue gas waste heat utilization system for chemical water heating in the thermal power plant is appropriate according to the generated pressure signal, so as to facilitate real-time adjustment, thereby ensuring the heat exchange effect.

[0056] Continue reading Figure 2 As shown, further, in some other embodiments, the monitoring mechanism also includes a heat meter 53 and a water meter 54. The heat meter 53 is installed on the first water pipe to monitor the initial heat input to the flue gas waste heat recovery mechanism 1 for chemical water production in real time. The water meter 54 is installed on the second water pipe to record the chemical water production amount of the flue gas waste heat recovery mechanism 1 in real time, so as to ensure the normal and orderly operation of the flue gas waste heat utilization system for chemical water production heating in the thermal power plant.

[0057] In some embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant further includes an opening control mechanism, specifically a pipe opening control device for controlling the flue gas flow rate in the flue gas circuit 2. In the embodiment of the present application, the opening control mechanism includes a first opening valve 61 installed in the first flue gas duct 21, and a second opening valve 62 installed in the second flue gas duct 22, and the first opening valve 61 and the second opening valve 62 are respectively used to adjust the real-time flow rate of flue gas in the first flue gas duct 21 and the second flue gas duct 22.

[0058] Specifically, the first opening valve 61 and / or the second opening valve 62 include a plurality of different opening positions. During the operation of the flue gas waste heat utilization system for chemical water heating in a thermal power plant, the operator can twist the first opening valve 61 and / or the second opening valve 62 to a corresponding opening position according to the acquired temperature signal, so that the flue gas temperature measured by the fourth temperature measuring component 514 can meet the requirements of subsequent processing.

[0059] In some other embodiments, the first opening valve 61 and the second opening valve 62 may also be electric baffle valves, and the first opening valve 61 and the second opening valve 62 are respectively connected to the above-mentioned monitoring mechanism by signal, so that the first opening valve 61 and / or the second opening valve 62 can switch to the corresponding opening position according to the acquired temperature signal, thereby realizing intelligent control of the flue gas flow rate in the flue gas circuit 2.

[0060] Furthermore, in some other embodiments, the opening control mechanism also includes a gate valve installed in the first flue gas duct 21 and / or the second flue gas duct 22. When the above-mentioned first opening valve 61 and the second opening valve 62 are out of control, the operator can perform full opening or full closing operation by closing the gate valve.

[0061] See also Figure 1 and Figure 2 As shown, in some embodiments, the flue gas waste heat utilization system for chemical water heating in a thermal power plant also includes a condensate discharge mechanism 8 connected to the flue gas waste heat recovery mechanism 1, and the condensate discharge mechanism 8 is used to discharge the condensate generated in the heat exchange process from the flue gas waste heat recovery mechanism 1.

[0062] The condensate discharge mechanism 8 includes a condensate input pipe 81 and a water storage member 82. The condensate input pipe 81 is connected between the above-mentioned flue gas waste heat recovery mechanism 1 and the water storage member 82, so as to drain the condensate from the flue gas waste heat recovery mechanism 1 to the water storage member 82, thereby realizing the recovery and storage of the condensate. In the embodiment of the present application, the water storage member 82 can specifically be a pit. During drainage, the fourth outlet port F of the flue gas waste heat recovery mechanism 1 is connected to the condensate input pipe 81, and the eighth outlet port M of the condensate input pipe 81 is connected to the pit, thereby draining the condensate into the pit.

[0063] In some other embodiments, the condensate discharge mechanism 8 further includes a condensate output pipe 83 and a driving member 84, the fifth inlet end N of the condensate output pipe 83 is connected to the water storage member 82, and the driving member 84 is installed in the water storage member 82 and connected to the condensate output pipe 83, so that the condensate is discharged from the water storage member 82 through the condensate output pipe 83 under the drive of the driving member 84. In the embodiment of the present application, the driving member 84 can specifically be an electric submersible pump.

[0064] Furthermore, in some other embodiments, the condensed water discharge mechanism 8 further includes a liquid level monitoring component 86 installed in the water storage component 82, and the liquid level monitoring component 86 is used to monitor the water level inside the water storage component 82 in real time. In the embodiment of the present application, the liquid level monitoring component 86 can be connected to the above-mentioned driving component 84 by signal, so that the driving component 84 can be controlled to start when the liquid level monitoring component 86 detects that the actual water level inside the water storage component 82 exceeds the preset water level, thereby reducing the situation where the condensed water overflows the water storage component 82 without being treated, causing environmental pollution.

[0065] Continue reading Figure 2As shown, further, in order to prevent the pH value of the condensed water from being too low and causing corrosion to the surrounding environment, in some other embodiments, the condensed water discharge mechanism 8 also includes a dosing component 85 connected to the condensed water output pipe 83. Driven by the driving member 84, the condensed water can flow through the dosing component 85 during the discharge process, so that the medicine in the dosing component 85 can neutralize the pH value of the condensed water, further reducing the possibility of the discharged condensed water causing pollution to the surrounding environment.

[0066] In the embodiment of the present application, the dosing component 85 can be a dosing tank filled with alkaline substances, and a place of the fifth inlet end N and the ninth outlet end O of the condensed water output pipe 83 can be connected to the fourth inlet end I of the dosing component 85. Among them, the outlet end of the dosing component 85 is provided with a sixth outlet end J and a seventh outlet end K, which merge to the tenth outlet end P, and the flue gas condensate can finally be discharged through the ninth outlet end O of the condensed water output pipe 83 and the tenth outlet end P of the dosing component 85.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A flue gas waste heat utilization system for chemical water heating in a thermal power plant, characterized in that: The flue gas waste heat utilization system comprises: A flue gas waste heat recovery mechanism, comprising a flue gas heat exchange pipe and a water heat exchange pipe, wherein the flue gas heat exchange pipe is configured to be mutually overlapped or at least partially in contact with the water heat exchange pipe, so that the flue gas in the flue gas heat exchange pipe can heat the chemical water in the water heat exchange pipe; A flue gas circuit comprises a first flue gas duct and a second flue gas duct, wherein the flue gas heat exchange pipe is connected between the first flue gas duct and the second flue gas duct, and one end of the first flue gas duct and the second flue gas duct away from the flue gas heat exchange pipe is used to connect to a main flue gas duct; either the first flue gas duct or the second flue gas duct is used to transport the flue gas in the main flue gas duct to the flue gas heat exchange pipe, and the other one is used to transport the flue gas after heat exchange in the flue gas heat exchange pipe back to the main flue gas duct; The chemical raw water circuit includes a first water supply pipeline and a second water supply pipeline. The water heat exchange pipe is connected between the first water supply pipeline and the second water supply pipeline. Any one of the first water supply pipeline and the second water supply pipeline is used to transport chemical raw water to the water heat exchange pipe, and the other is used to output the heated chemical raw water to the raw water heater.

2. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 1, characterized in that: The flue gas waste heat utilization system also includes a flushing mechanism, which includes a spray component and a flushing pipe connected to the spray component. The spray component is installed on the water heat exchange pipe, and the flushing pipe is used to supply water to the spray component to clean the water heat exchange pipe.

3. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 2, characterized in that: The flue gas waste heat utilization system further comprises a monitoring mechanism, wherein the monitoring mechanism comprises a temperature monitoring component and a pressure monitoring component installed in the flue gas circuit and / or the chemical water production circuit and / or the flushing mechanism; Among them, the temperature monitoring component is used to monitor the real-time temperature of the flue gas circuit and / or the chemical water discharge circuit to generate a temperature signal; the pressure monitoring component is used to monitor the real-time pressure of water in the chemical water discharge circuit and / or the flushing pipe to generate a pressure signal.

4. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 3 is characterized in that: The temperature monitoring assembly comprises a first temperature measuring element, a second temperature measuring element, a third temperature measuring element and a fourth temperature measuring element arranged at intervals, the first temperature measuring element is installed on the first water pipeline, the second temperature measuring element is installed on the second water pipeline, the third temperature measuring element is installed on the first flue gas pipeline, and the fourth temperature measuring element is installed on the second flue gas pipeline; Among them, the first temperature measuring component is used to monitor the temperature of chemical water in the first water supply pipeline, the second temperature measuring component is used to monitor the temperature of chemical water in the second water supply pipeline, the third temperature measuring component is used to monitor the temperature of smoke in the first smoke pipe, and the fourth temperature measuring component is used to monitor the temperature of smoke in the second smoke pipe, so as to obtain the temperature signal.

5. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 3, characterized in that: The pressure monitoring assembly includes a first pressure measuring piece, a second pressure measuring piece and a third pressure measuring piece arranged at intervals. The first pressure measuring piece is installed in the first water pipeline to monitor the water pressure inside the first water pipeline, the second pressure measuring piece is installed in the second water pipeline to monitor the water pressure inside the second water pipeline, and the third pressure measuring piece is installed in the flushing pipeline to monitor the water pressure inside the flushing pipeline, thereby obtaining the pressure signal.

6. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 3, characterized in that: The flue gas waste heat utilization system also includes an opening control mechanism, which can be signal-connected to the monitoring mechanism; the opening control mechanism includes a first opening valve installed in the first flue gas duct and a second opening valve installed in the second flue gas duct.

7. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 6, characterized in that: The first opening valve and / or the second opening valve include a plurality of different opening positions, and the first opening valve and / or the second opening valve can be switched to the corresponding opening position according to the temperature signal to achieve regulation of the flue gas flow rate in the flue gas circuit.

8. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 1, characterized in that: The flue gas waste heat utilization system also includes a drainage mechanism, which is installed in the flue gas circuit so that the flue gas can flow from the first flue gas duct through the flue gas heat exchange tube to the second flue gas duct, or so that the flue gas can flow from the second flue gas duct through the flue gas heat exchange tube to the first flue gas duct.

9. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 1, characterized in that: The flue gas temperature in the first flue gas duct is controlled at 120°C to 160°C, and the flue gas temperature in the second flue gas duct is controlled at less than 60°C.

10. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 1, characterized in that: The flue gas waste heat utilization system also includes a condensate discharge mechanism connected to the flue gas waste heat recovery mechanism, the condensate discharge mechanism includes a condensate input pipe and a water storage member, the condensate input pipe is connected between the flue gas waste heat recovery mechanism and the water storage member to discharge condensate from the flue gas waste heat recovery mechanism to the water storage member for storage.

11. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 10, characterized in that: The condensed water discharge mechanism further includes a condensed water output pipe and a driving member, wherein the condensed water output pipe is connected to the water storage member, and the driving member is installed on the condensed water output pipe to drive the condensed water to be discharged from the water storage member.

12. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 11, characterized in that: The condensate discharge mechanism further includes a dosing component connected to the condensate output pipe. Driven by the driving member, the condensate can flow through the dosing component, and the dosing component is used to neutralize the pH value of the condensate flowing through.

13. The flue gas waste heat utilization system for chemical water heating in a thermal power plant according to claim 11, characterized in that: The condensed water discharge mechanism further comprises a liquid level monitoring component, which is installed on the water storage component and monitors the water level inside the water storage component. The liquid level monitoring component can be connected to the driving component by signal.

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