Thermal generator set low-quality heat comprehensive utilization system and control method

Abstract

The invention provides a thermal generator set low-quality heat comprehensive utilization system and a control method, and relates to the technical field of thermal generator sets, the thermal generator set low-quality heat comprehensive utilization system comprises a regular drainage pool, a boiler regular drainage flash tank, a stainless steel water tank, a linkage control assembly, a heat recycling end and an overflow pipe. Through sequential treatment of the regular drainage pool, the boiler regular drainage flash tank and the stainless steel water tank, stable storage and pretreatment of high-temperature and high-pressure wastewater are achieved, and by means of real-time monitoring and threshold value control of a temperature sensor and a liquid level meter, it is ensured that only the wastewater meeting the heat utilization condition is recycled to the heat supply urban network water return main pipe and the bath water pool, and the heat utilization efficiency is improved. Ineffective conveying of low-quality heat is avoided, the overflow risk caused by the fact that the stainless steel water tank is full of water is effectively prevented through the arrangement of the overflow pipe, directional recovery and efficient utilization of the low-quality heat of the thermal generator set are achieved through the whole system, heat energy waste caused by traditional direct emission is reduced, and the steam production cost is reduced. And the energy utilization efficiency of the unit is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal power generating units, and particularly relates to a low-quality heat comprehensive utilization system and control method for a thermal power generating unit. BACKGROUND

[0002] In the operation process of a thermal power generating unit, a boiler as a core equipment needs to discharge boiler water with high salt content and high impurity concentration through continuous and periodic blowdown to maintain the quality of the boiler water and ensure the safe and stable operation of the boiler. The blowdown wastewater usually has high temperature and pressure and belongs to typical low-quality waste heat resources. In the traditional treatment mode, the high-temperature and high-pressure wastewater is directly discharged without effective recycling, which not only causes a large amount of heat energy to be wasted, resulting in a low energy utilization rate, but also easily causes thermal pollution to the surrounding environment due to the high temperature of the wastewater. In addition, the salt and alkali components and impurities in the untreated wastewater may cause pipeline corrosion and scaling if directly discharged into natural water bodies or municipal pipelines, thereby increasing the subsequent treatment cost. In addition, the heat recovery system of the existing thermal power generating unit mainly focuses on the utilization of high-quality steam heat energy, and the concern for such low-quality waste heat is relatively low. There is a lack of a special comprehensive utilization system and a matching control method, which leads to a low recovery efficiency of the low-quality heat and cannot fully play the potential value of the low-quality heat in heating, bathing and auxiliary deoxidization. SUMMARY

[0003] The application provides a low-quality heat comprehensive utilization system and control method for a thermal power generating unit to solve at least one of the above technical problems.

[0004] To solve the above technical problems, the application discloses a low-quality heat comprehensive utilization system and control method for a thermal power generating unit, which comprises: a blowdown tank for storing high-temperature and high-pressure wastewater discharged by the thermal power generating unit; a boiler blowdown expander installed at the outlet end of the blowdown tank and used for expanding and depressurizing the high-temperature and high-pressure wastewater discharged by the blowdown tank, wherein an electric valve one and an electric valve two are installed on the boiler blowdown expander; a stainless steel water tank for storing the high-temperature and high-pressure wastewater treated by the boiler blowdown expander; a linkage control assembly comprising a temperature sensor, a liquid level meter, a recovery water pump one and a recovery water pump two, wherein the temperature sensor and the liquid level meter are both installed at the top of the stainless steel water tank and used for detecting the temperature and liquid level of the wastewater in the stainless steel water tank, and the recovery water pump one and the recovery water pump two are both installed at the outlet end of the stainless steel water tank and used for pumping the wastewater in the stainless steel water tank to a heat recovery and utilization end; The heat recycling end comprises a heat supply city network backwater main pipe and a bath water pool, and the heat supply city network backwater main pipe and the bath water pool are respectively communicated with the output ends of the recycling water pump one and the recycling water pump two. The overflow pipe is installed between the top of the stainless steel water tank and the fixed drainage pool, and is used for preventing the stainless steel water tank from being full of water.

[0005] Preferably, the heat recycling end further comprises: The online water quality analyzer is installed at the water inlet of the stainless steel water tank, and is used for monitoring the pH value, turbidity and dissolved solid content of the wastewater in real time. The automatic dosing unit is used for adding scale inhibitor and neutralizing agent into the stainless steel water tank based on the detection result of the online water quality analyzer, so as to prevent the heat exchange surface from being scaled and corroded.

[0006] Preferably, the amount of the scale inhibitor and the neutralizing agent added into the stainless steel water tank is calculated based on the pH value, turbidity and dissolved solid content of the wastewater monitored by the online water quality analyzer, and specifically comprises: ; ; wherein, is the volume of the neutralizing agent added into the stainless steel water tank, is the neutralizing agent addition ratio coefficient, is the volume of the current wastewater in the stainless steel water tank, is the preset target pH value, is the wastewater pH value measured by the online water quality analyzer, is the pH correction coefficient, is the volume of the scale inhibitor added into the stainless steel water tank, is the scale inhibitor addition ratio coefficient, is the dissolved solid content weight coefficient, is the wastewater dissolved solid content measured by the online water quality analyzer, is the preset dissolved solid content threshold value, is the turbidity weight coefficient, is the wastewater turbidity measured by the online water quality analyzer, is the preset turbidity threshold value.

[0007] Preferably, the heat recycling end further comprises an oxygen remover, and the oxygen remover is connected to the output end of the recycling water pump one through a branch pipeline. When the real-time temperature T is greater than or equal to the preset oxygen removal temperature threshold value T1, the recycling water pump one transports part of the high-temperature wastewater to the oxygen remover, and the wastewater heat is used to heat the feed water and assist in oxygen removal.

[0008] Preferably, the linkage control assembly comprises a dynamic anti-freezing protection module, and the dynamic anti-freezing protection module comprises an electric heating tape wound on the surface of the overflow pipe, and the start-stop control algorithm of the electric heating tape is as follows: ; wherein, Pout is the output power of the electric heat tracing band, Tf is the freeze protection temperature setting, T is the measured value of the ambient temperature sensor, K is the proportional coefficient, Ki is the integral coefficient.

[0009] Preferably, the flow distribution of the recovery water pump one and the recovery water pump two adopts a heat load optimization algorithm: wherein, Qp is the flow pumped into the heat supply city network return water main pipe, Qb is the flow pumped into the bath water pool, ΔT is the allowable temperature rise value of the heat supply pipe network, ΔTb is the target temperature rise value of the bath water pool, Cv is the specific heat capacity of the waste water, η is the net heat efficiency coefficient of the bath water pool, Kp is the priority weight factor.

[0010] Preferably, the stainless steel water tank adopts a double-layer insulation structure, comprising: an inner container layer made of 316L stainless steel, resistant to high temperature corrosion; a vacuum insulation layer wrapped outside the inner container layer, reducing heat loss during heat storage.

[0011] Preferably, the spiral settling inclined plate is arranged in the fixed drainage pool, with an inclination angle of 60° and a plate spacing of ≤50mm, for accelerating the settlement and separation of heavy metal particles.

[0012] A control method of a low-quality heat comprehensive utilization system of a thermal power generating unit, comprising the following steps: Step one, open the electric valve one and the electric valve two installed on the boiler fixed drainage expander at the outlet end of the fixed drainage pool, so that the high-temperature and high-pressure waste water discharged from the fixed drainage pool enters the stainless steel water tank after being expanded and depressurized by the boiler fixed drainage expander; Step two, detect the real-time temperature T of the waste water in the stainless steel water tank through the temperature sensor installed at the top of the stainless steel water tank, and detect the real-time liquid level H of the waste water in the stainless steel water tank through the liquid level meter installed at the top of the stainless steel water tank; Step three, preset the temperature threshold T0 and the liquid level threshold H0, when the real-time temperature T≥T0 and the real-time liquid level H≥H0, start the recovery water pump one and the recovery water pump two installed at the outlet end of the stainless steel water tank, the recovery water pump one pumps the waste water in the stainless steel water tank into the heat supply city network return water main pipe, and the recovery water pump two pumps the waste water in the stainless steel water tank into the bath water pool; When the real-time temperature T<T0 or the real-time liquid level H<H0, stop the recovery water pump one and the recovery water pump two from running; Step four, when the real-time liquid level of the wastewater in the stainless steel tank exceeds the preset liquid level of the overflow pipe installed on the upper part, the excess part of the wastewater is discharged through the overflow pipe to prevent the stainless steel tank from being full of water.

[0013] Preferably, it further comprises the following steps: Step five, the pH value, turbidity and dissolved solid content of the wastewater in the stainless steel tank are monitored in real time by the online water quality analyzer, and based on the calculated dosing amount of the neutralizing agent and the scale inhibitor, the corresponding amount of the neutralizing agent and the scale inhibitor is added into the stainless steel tank by controlling the automatic dosing unit; Step six, when the ambient temperature detected by the ambient temperature sensor is ≤ , the dynamic anti-freezing protection module is started, and the output power P of the electric heating tape on the surface of the overflow pipe is controlled to prevent the overflow pipe from freezing, when > , the electric heating tape is turned off.

[0014] Compared with the prior art, the present application has the following beneficial effects: The present application realizes stable storage and pretreatment of high-temperature and high-pressure wastewater through the sequential treatment of the fixed discharge tank, the boiler fixed discharge expansion vessel and the stainless steel tank, and ensures that only the wastewater meeting the heat utilization conditions is recycled to the heating city network backwater main pipe and the bath water tank by using real-time monitoring and threshold control of the temperature sensor and the liquid level meter, thereby avoiding the invalid delivery of low-quality heat, and the overflow pipe effectively prevents the overflow risk caused by the full water of the stainless steel tank. The overall system realizes the directional recycling and efficient utilization of low-quality heat of the thermal power generating unit, reduces the waste of heat energy caused by traditional direct discharge, reduces the steam production cost, and improves the energy utilization efficiency of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments thereof, and explain the present application, but do not constitute a limitation of the present application. In the drawings: Figure 1 is a schematic diagram of the low-quality heat comprehensive utilization system of the thermal power generating unit of the present application.

[0016] In the figure: 1, electric valve one; 2, electric valve two; 3, overflow pipe; 4, liquid level meter; 5, temperature sensor; 6, fixed discharge tank; 7, recovery water pump one; 8, recovery water pump two; 9, boiler fixed discharge expansion vessel; 10, stainless steel tank; 11, heating city network backwater main pipe; 12, bath water tank. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and do not limit the present application.

[0018] In addition, the description such as "first", "second", etc. in the present application is only for the purpose of description, not the meaning of indicating the order or sequence, nor to limit the present application, which is only to distinguish the components or operations described by the same technical terms, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions and technical features between various embodiments can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor in the protection scope required by the present application.

[0019] The present application provides the following embodiments Embodiment 1 The embodiment of the present application provides a low-quality heat comprehensive utilization system and control method of thermal power generating unit, as shown in the figure, comprising: Figure 1 The fixed drainage pool 6 is used for storing high-temperature and high-pressure wastewater discharged by the thermal power generating unit; The boiler fixed drainage expander 9 is installed at the outlet end of the fixed drainage pool 6, which is used for expanding and reducing the pressure of the high-temperature and high-pressure wastewater discharged by the fixed drainage pool 6. The boiler fixed drainage expander 9 is provided with electric valve one 1 and electric valve two 2; The stainless steel water tank 10 is used for storing high-temperature and high-pressure wastewater treated by the boiler fixed drainage expander 9; The linkage control assembly comprises a temperature sensor 5, a liquid level meter 4, a recovery water pump one 7 and a recovery water pump two 8. The temperature sensor 5 and the liquid level meter 4 are both installed at the top of the stainless steel water tank 10 and are used for detecting the temperature and liquid level of the wastewater in the stainless steel water tank 10. The recovery water pump one 7 and the recovery water pump two 8 are both installed at the outlet end of the stainless steel water tank 10 and are used for pumping the wastewater in the stainless steel water tank 10 into the heat recovery end; The heat recovery end comprises a heat supply city network return water main pipe 11 and a bath water pool 12, which are respectively communicated with the output ends of the recovery water pump one 7 and the recovery water pump two 8; The overflow pipe 3 is installed between the top of the stainless steel water tank 10 and the fixed drainage pool 6, which is used for preventing the stainless steel water tank 10 from being full of water.

[0020] A control method of a low-quality heat comprehensive utilization system of a thermal power generating unit, comprising the following steps: ​Step one, open the electric valve 1 and electric valve 2 installed on the boiler blowdown expansion vessel 9 at the outlet end of the blowdown tank 6, so that the high-temperature and high-pressure wastewater discharged from the blowdown tank 6 enters the stainless steel tank 10 after expansion and pressure reduction by the boiler blowdown expansion vessel 9; Step two, detect the real-time temperature T of the wastewater in the stainless steel tank 10 by the temperature sensor 5 installed at the top of the stainless steel tank 10, and detect the real-time liquid level H of the wastewater in the stainless steel tank 10 by the liquid level meter 4 installed at the top of the stainless steel tank 10; Step three, preset the temperature threshold T0 and the liquid level threshold H0, when the real-time temperature T≥T0 and the real-time liquid level H≥H0, start the recovery water pump 1 and the recovery water pump 2 installed at the outlet end of the stainless steel tank 10, the recovery water pump 1 pumps the wastewater in the stainless steel tank 10 into the heating city network return water main pipe 11, and the recovery water pump 2 pumps the wastewater in the stainless steel tank 10 into the bath water tank 12; When the real-time temperature T<T0 or the real-time liquid level H<H0, stop the recovery water pump 1 and the recovery water pump 2 from running; Step four, when the real-time liquid level of the wastewater in the stainless steel tank 10 exceeds the preset liquid level of the overflow pipe 3 installed at the top of the stainless steel tank 10, the excess part of the wastewater is discharged through the overflow pipe 3 to prevent the stainless steel tank 10 from being full of water; Step five, monitor the pH value, turbidity and dissolved solid content of the wastewater in the stainless steel tank 10 in real time by the online water quality analyzer, based on the calculated dosing amount of the neutralizing agent and the scale inhibitor, control the automatic dosing unit to add the corresponding amount of the neutralizing agent and the scale inhibitor into the stainless steel tank 10; Step six, when the ambient temperature detected by the ambient temperature sensor is ≤ Step seven, start the dynamic anti-freezing protection module, and control the output power P of the electric heating tape on the surface of the overflow pipe 3 to prevent the overflow pipe 3 from freezing, when > Step eight, turn off the electric heating tape.

[0021] Preferably, the stainless steel tank 10 adopts a double-layer insulation structure, including: The inner tank layer is made of 316L stainless steel, which can resist high-temperature corrosion; The vacuum insulation layer is wrapped outside the inner tank layer to reduce heat loss during heat storage.

[0022] Preferably, the blowdown tank 6 is provided with a spiral settling inclined plate with an inclination angle of 60° and a plate spacing of ≤50mm, which is used to accelerate the settlement and separation of heavy metal particles.

[0023] In this embodiment, T is the real-time temperature of the wastewater in the stainless steel tank 10, in units of ℃, detected by the temperature sensor 5; T0 is the preset temperature threshold, in units of ℃, set according to the heat utilization requirements of the heat supply city network return water main pipe 11 and the bath water pool 12; H is the real-time liquid level of the wastewater in the stainless steel tank 10, in units of m, detected by the liquid level meter 4; H0 is the preset liquid level threshold, in units of m, set according to the effective water storage space of the stainless steel tank 10 and the operation requirements of the recovery water pump one 7 and the recovery water pump two 8.

[0024] The working principle and beneficial effects of the above technical solution are as follows: The high-temperature and high-pressure wastewater discharged by the thermal power generator set first enters the fixed discharge pool 6 for storage, then passes through the boiler fixed discharge expander 9 at the outlet end of the fixed discharge pool 6 for expansion and pressure reduction, enters the stainless steel tank 10 for storage through the electric valve one 1 and the electric valve two 2 on the boiler fixed discharge expander 9, and the temperature sensor 5 and the liquid level meter 4 installed at the top of the stainless steel tank 10 detect the real-time temperature T and the real-time liquid level H of the wastewater respectively. When T ≥ the preset temperature threshold T0 and H ≥ the preset liquid level threshold H0, the recovery water pump one 7 and the recovery water pump two 8 at the outlet end of the stainless steel tank 10 start to pump the wastewater into the heat supply city network return water main pipe 11 and the bath water pool 12 respectively. When T < T0 or H < H0, the recovery water pump one 7 and the recovery water pump two 8 stop running. At the same time, when the liquid level in the stainless steel tank 10 exceeds the preset liquid level of the overflow pipe 3, the overflow pipe 3 discharges the excess wastewater to the fixed discharge pool 6 to prevent the tank from being full of water. Through the sequential processing of the fixed discharge pool 6, the boiler fixed discharge expander 9, and the stainless steel tank 10, stable storage and pretreatment of high-temperature and high-pressure wastewater are achieved. The real-time monitoring and threshold control of the temperature sensor 5 and the liquid level meter 4 ensure that only wastewater that meets the heat utilization conditions is recovered to the heat supply city network return water main pipe 11 and the bath water pool 12, avoiding the ineffective delivery of low-quality heat. The setting of the overflow pipe 3 effectively prevents the risk of overflow caused by the stainless steel tank 10 being full of water. The overall system realizes the directional recovery and efficient utilization of low-quality heat from the thermal power generator set, reduces the waste of thermal energy caused by traditional direct discharge, reduces the cost of steam production, and improves the energy utilization efficiency of the unit.

[0025] Embodiment 2 Based on the embodiment 1, it further includes: An online water quality analyzer is installed at the inlet of the stainless steel tank 10 for real-time monitoring of the pH value, turbidity, and dissolved solid content of the wastewater. An automatic dosing unit is used to add scale inhibitors and neutralizing agents into the stainless steel tank 10 based on the detection results of the online water quality analyzer to prevent scale and corrosion on the heat exchange surface.

[0026] Preferably, the pH value, turbidity and dissolved solid content of the wastewater monitored by the online water quality analyzer are used to calculate the amount of scale inhibitor and neutralizing agent to be added to the stainless steel water tank 10, specifically including: ; ; wherein, is the volume of the neutralizing agent to be added to the stainless steel water tank 10, is the neutralizing agent addition ratio coefficient, is the volume of the current wastewater in the stainless steel water tank 10, is the preset target pH value, is the measured wastewater pH value by the online water quality analyzer, is the pH correction coefficient, is the volume of the scale inhibitor to be added to the stainless steel water tank 10, is the scale inhibitor addition ratio coefficient, is the dissolved solid content weight coefficient, is the measured wastewater dissolved solid content by the online water quality analyzer, is the preset dissolved solid content threshold value, is the turbidity weight coefficient, is the measured wastewater turbidity by the online water quality analyzer, is the preset turbidity threshold value.

[0027] The working principle and beneficial effects of the above technical solution are as follows: by monitoring the pH value, turbidity and dissolved solid content of the wastewater in real time by the online water quality analyzer, dynamic control of water quality parameters is achieved, and the automatic dosing unit accurately calculates and adds the neutralizing agent and scale inhibitor based on the monitoring data and specific formula. The neutralizing agent addition amount formula is calculated according to the difference between the target pH value and the measured pH value, the wastewater volume and the pH correction coefficient, and the scale inhibitor addition amount formula is calculated according to the difference between the measured value and the set value of the dissolved solid content and turbidity, the weight coefficient and the wastewater volume, which ensures accurate matching of the addition amount and the water quality condition, effectively prevents scaling and corrosion of the heat exchange surface due to water quality problems, prolongs the service life of the system equipment, reduces the heat efficiency due to scaling, reduces the labor intensity and error of manual dosing, and improves the stability and economy of system operation.

[0028] Embodiment 3 Based on embodiment 1, the heat recovery end further includes a deaerator connected to the output end of the recovery water pump 1 through a branch pipeline; When the real-time temperature T is greater than or equal to the preset deaeration temperature threshold T1, the recovery water pump 1 sends part of the high-temperature wastewater to the deaerator to heat the feedwater and assist deaeration using waste heat.

[0029] The working principle and beneficial effects of the above technical solution are as follows: by adding the deaerator and utilizing the waste heat of the high-temperature wastewater, the further cascade utilization of low-quality heat is realized; when the wastewater temperature reaches the preset deaeration temperature threshold, part of the wastewater is transported to the deaerator, which not only utilizes the waste heat to heat the feed water, but also assists in improving the deaeration effect, reduces the consumption of additional steam or energy by the deaerator, and reduces the overall energy consumption of the unit. At the same time, the reuse of waste heat improves the energy utilization efficiency of the system, reduces heat waste, meets the requirements of energy saving and consumption reduction, and also reduces the operation cost of the deaerator.

[0030] Embodiment 4 On the basis of embodiment 1, the linkage control assembly comprises a dynamic anti-freezing protection module, which includes an electric heat tracing band wound around the surface of the overflow pipe 3, and the start-stop control algorithm thereof is as follows: ; wherein, P is the output power of the electric heat tracing band, T is the anti-freezing set temperature, T is the measured value of the environment temperature sensor, Kp is a proportional coefficient, Ki is an integral coefficient.

[0031] The working principle and beneficial effects of the above technical solution are as follows: the dynamic anti-freezing protection module realizes accurate anti-freezing of the overflow pipe 3; the start-stop and output power of the electric heat tracing band are regulated based on the deviation between the environment temperature and the anti-freezing set temperature; in the control algorithm, the output power P is proportional to the difference between the set temperature and the environment temperature, is adjusted by the proportional coefficient Kp, and is corrected by superimposing the integral coefficient Ki, which ensures reasonable output of the electric heat tracing band power under different environment temperatures, effectively prevents the overflow pipe 3 from freezing and blocking in a low-temperature environment, avoids excessive consumption of energy, guarantees stable operation of the system in winter or a low-temperature environment, reduces system failure and maintenance cost caused by freezing of the overflow pipe, and improves the environmental adaptability of the system.

[0032] Embodiment 5 On the basis of embodiment 1, the flow distribution of the recovery water pump one 7 and the recovery water pump two 8 adopts a heat load optimization algorithm: ; wherein, Q is the flow of the pump-in heating city network backwater mother pipe 11, Q is the flow of the pump-in bathwater pool 12, ΔT is the allowable temperature rise value of the heating pipe network, ΔT is the target temperature rise value of the bathwater pool, C is the specific heat capacity of the wastewater, η is the net heat efficiency coefficient of the bathwater pool, K is a priority weight factor.

[0033] The working principle and beneficial effects of the technical scheme are as follows: the heat load optimization algorithm is used to realize accurate flow distribution of the recovery water pump 7 and the recovery water pump 8, the product of the flow ratio and the allowable temperature rise value of the heat supply pipe network and the specific heat capacity of waste water is directly proportional to the product of the target temperature rise value of the bath pool and the net heat efficiency coefficient of the bath pool, and the priority of different heat utilization ends is adjusted through the priority weight factor α, so that the flow distribution is matched with the actual heat load demand of the heat supply network and the bath pool, the situation of excessive or insufficient heat of a utilization end is avoided, the utilization efficiency of low-quality heat is improved, and the waste of heat energy is reduced, meanwhile, the dynamic flow regulation enhances the adaptability of the system to different heat load conditions, and improves the flexibility and economy of system operation.

[0034] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A system for comprehensive utilization of low-quality heat from a thermal power generating unit, characterized by: include: A fixed drainage pool (6) for storing high-temperature and high-pressure wastewater discharged from the thermal power generating unit; The boiler fixed discharge expansion container (9) is installed at the outlet of the fixed discharge tank (6) and is used to expand and reduce the pressure of the high-temperature and high-pressure wastewater discharged from the fixed discharge tank (6). The boiler fixed discharge expansion container (9) is installed with an electric valve 1 (1) and an electric valve 2 (2); A stainless steel water tank (10) for storing high-temperature and high-pressure wastewater treated by the boiler fixed-discharge expansion tank (9); A linkage control component comprises a temperature sensor (5), a liquid level gauge (4), a recovery water pump 1 (7) and a recovery water pump 2 (8), wherein the temperature sensor (5) and the liquid level gauge (4) are both mounted on the top of the stainless steel water tank (10) and are used to detect the temperature and liquid level of the wastewater in the stainless steel water tank (10), respectively; the recovery water pump 1 (7) and the recovery water pump 2 (8) are both mounted on the outlet end of the stainless steel water tank (10), and the recovery water pump 1 (7) and the recovery water pump 2 (8) are used to pump the wastewater in the stainless steel water tank (10) into the heat recovery and utilization end; The heat recovery and utilization end includes a heat supply network return water main pipe (11) and a bath water pool (12), wherein the heat supply network return water main pipe (11) and the bath water pool (12) are respectively connected to the output ends of the recovery water pump 1 (7) and the recovery water pump 2 (8); The overflow pipe (3) is installed between the top of the stainless steel water tank (10) and the fixed drainage tank (6) to prevent the stainless steel water tank (10) from being filled with water.

2. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: Also includes: An online water quality analyzer is installed at the water inlet of the stainless steel water tank (10) to monitor the pH value, turbidity and dissolved solids content of the wastewater in real time; The automatic dosing unit is used to add scale inhibitors and neutralizers into the stainless steel water tank (10) based on the detection results of the online water quality analyzer to prevent scaling and corrosion on the heat exchange surface.

3. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 2, characterized in that: Based on the pH value, turbidity and dissolved solids content of the wastewater monitored by the online water quality analyzer, the amount of scale inhibitor and neutralizer to be added to the stainless steel water tank (10) is calculated, specifically including: ； ;in, is the volume of neutralizer added to the stainless steel water tank (10), is the neutralizer dosage ratio coefficient, is the current volume of wastewater in the stainless steel water tank (10), is the preset target pH value, is the pH value of wastewater measured by the online water quality analyzer, is the pH correction factor, is the volume of scale inhibitor added to the stainless steel water tank (10), is the scale inhibitor dosage coefficient, is the weight coefficient of dissolved solid content, is the dissolved solid content of wastewater measured by the online water quality analyzer, is the preset dissolved solids content threshold, is the turbidity weight coefficient, is the wastewater turbidity measured by the online water quality analyzer, is the preset turbidity threshold.

4. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: The heat recovery end also includes a deaerator, which is connected to the output end of the recovery water pump (7) through a branch pipeline; When the real-time temperature T≥the preset deoxygenation temperature threshold T1, the recovery water pump 1 (7) transports part of the high-temperature wastewater to the deaerator, using the waste heat to heat the feed water and assist in deoxygenation.

5. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: The linkage control component includes a dynamic antifreeze protection module, including an electric heating tape wrapped around the surface of the overflow pipe (3), and its start-stop control algorithm is as follows: ;in, is the output power of the electric heating cable, Set the temperature for antifreeze, is the actual value measured by the ambient temperature sensor, is the proportionality coefficient, is the integration coefficient.

6. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: The flow distribution of the recovery water pump 1 (7) and the recovery water pump 2 (8) adopts the heat load optimization algorithm: ;in, is the flow rate pumped into the return pipe (11) of the heating network, is the flow rate of the water pumped into the bathing pool (12), is the allowable temperature rise value of the heating network, is the target temperature rise of the bathing pool, is the specific heat capacity of wastewater, is the net thermal efficiency coefficient of the bathing pool, is the priority weight factor.

7. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: The stainless steel water tank (10) adopts a double-layer insulation structure, comprising: The inner layer is made of 316L stainless steel, resistant to high temperature corrosion; The vacuum insulation layer is wrapped around the outside of the inner liner to reduce heat loss during the heat storage process.

8. The low-quality heat comprehensive utilization system of a thermal power generating set according to claim 1, characterized in that: The fixed drainage tank (6) is provided with spiral sedimentation inclined plates with an inclination angle of 60° and a plate spacing of ≤50 mm, which are used to accelerate the sedimentation and separation of heavy metal particles.

9. A control method for a low-quality heat comprehensive utilization system for a thermal power generation unit, comprising a low-quality heat comprehensive utilization system for a thermal power generation unit according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Open the electric valve 1 (1) and electric valve 2 (2) installed on the boiler blowdown flash tank (9) at the outlet end of the constant drainage tank (6) to allow the high-temperature and high-pressure wastewater discharged from the constant drainage tank (6) and expanded and depressurized by the boiler blowdown flash tank (9) to enter the stainless steel water tank (10). Step 2: Detect the real-time temperature T of the wastewater in the stainless steel water tank (10) through the temperature sensor (5) installed on the top of the stainless steel water tank (10), and at the same time detect the real-time liquid level H of the wastewater in the stainless steel water tank (10) through the liquid level gauge (4) installed on the top of the stainless steel water tank (10). Step 3: Preset the temperature threshold T0 and the liquid level threshold H0. When the real-time temperature T≥T0 and the real-time liquid level H≥H0, start the recovery water pump 1 (7) and recovery water pump 2 (8) installed at the outlet end of the stainless steel water tank (10). The recovery water pump 1 (7) pumps the wastewater in the stainless steel water tank (10) into the return water main pipe (11) of the heating urban network, and the recovery water pump 2 (8) pumps the wastewater in the stainless steel water tank (10) into the bath water tank (12). When the real-time temperature T<T0 or the real-time liquid level H<H0, stop the operation of the recovery water pump 1 (7) and recovery water pump 2 (8). Step 4: When the real-time liquid level of the wastewater in the stainless steel water tank (10) exceeds the preset liquid level of the overflow pipe (3) installed above it, discharge the excess wastewater through the overflow pipe (3) to prevent the stainless steel water tank (10) from overflowing with water.

10. A control method for a low-quality heat comprehensive utilization system of a thermal power generating set according to claim 9, characterized in that: It also includes the following steps: Step 5: Real-time monitor the pH value, turbidity and dissolved solid content of the wastewater in the stainless steel water tank (10) through an online water quality analyzer. Based on the calculated dosage of the neutralizing agent and scale inhibitor, control the automatic dosing unit to add the corresponding amount of the neutralizing agent and scale inhibitor into the stainless steel water tank (10). Step 6: When the ambient temperature sensor detects the ambient temperature ≤ When the dynamic antifreeze protection module is started, the output power P of the electric heating cable on the surface of the overflow pipe (3) is controlled to prevent the overflow pipe (3) from freezing. > When the heating tape is turned off, turn off the heating tape.

Images