Dry quenching system non-working-condition operation flue gas waste heat recycling method
By adding a parallel water mixing heating system and a temperature recording interlock alarm in the dry coke quenching system, the problem of the temperature of the flue gas pipeline below 115℃ during non-working operation of the dry coke quenching system is solved, and water supply to deoxygenation water is achieved Effective heating and temperature monitoring prevent acid dew point corrosion and improve system stability and reliability.
Patent Information
- Application Number
- CN202411725807.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-02-07
AI Technical Summary
In the non-operating operation of the dry coke quenching system, the temperature of the inlet flue gas pipeline in the dry coke quenching body is often lower than 115°C, resulting in the pipe walls being subjected to acid dew point corrosion.
By adding a parallel mixed water heating system between the deoxygenation water supply pipe and the deoxygenation water supply pipe, and installing a temperature recording interlock alarm on the deoxygenation water supply pipe, monitoring and adjustment of the return water temperature is achieved. Ensure the temperature reaches the set value and prevent corrosion caused by too low temperature.
Effectively use the waste heat of dry quenching circulating flue gas to heat the deoxygenation feed water supply water supply to ensure that the temperature of the deoxygenation feed water return water remains within the predetermined value, prevent acid dew point corrosion of the inlet flue gas pipeline of the dry quenching body, and improve the system in the non-continuity Stability and reliability under operating conditions.
Smart Images
Figure CN119391436A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of flue gas waste heat recovery and utilization, and specifically relates to a method for recovering and utilizing waste heat from flue gas in a non-operating condition of a dry coke quenching system. Background Art
[0002] At present, the waste heat utilization system of CDQ cycle gas usually consists of heat pipe heat exchanger, desalted water tank, deaerator, deoxygenated feed water supply pipeline, return water pipeline and water pump. The flue gas at the outlet of 160℃ CDQ cycle fan and the deoxygenated feed water at 60℃ are heat exchanged in the heat pipe heat exchanger, the deoxygenated feed water return water is raised to 95℃, and the lower limit of the flue gas pipe temperature at the inlet of the CDQ body is controlled to be higher than 115℃, to prevent the sulfuric acid vapor in the flue gas from condensing and corroding the pipe wall when the pipe wall temperature is lower than the acid dew point corrosion temperature.
[0003] However, in actual production conditions, the temperature of the flue gas duct at the CDQ body inlet is often lower than 115°C. There are two reasons for this: Reason 1: The temperatures of the CDQ pre-storage chamber and the circulating fan outlet during conventional design are inconsistent with the temperatures of the CDQ pre-storage chamber and the circulating fan outlet during actual operation, resulting in the deaerated feed water supply temperature and the deaerated feed water return temperature applied to the conventional design flow being unsuitable for actual conditions; Reason 2: During conventional design, the CDQ system operates at full load, and no treatment measures are reserved for low load conditions. When the CDQ system operates at low load, the circulating gas temperature at the circulating fan outlet is lower than 160°C. Since the deaerated feed water supply and return water temperatures and flow rates remain unchanged, the deaerated feed water supply and return water heat absorption remains unchanged, causing the outlet temperature of the heat pipe heat exchanger to be lower than 115°C. Summary of the invention
[0004] Based on the above technical problems, the present invention provides a method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system. The device adds a parallel mixed water heating system between a deoxygenated water supply pipe and a deoxygenated water return pipe, and installs a temperature recording interlock alarm on the deoxygenated water return pipe, thereby facilitating monitoring of the return water temperature to ensure that the return water temperature reaches a set value, while avoiding the problem of acid dew point corrosion of the pipe wall of the dry coke quenching body inlet flue gas pipe due to too low temperature.
[0005] The specific technical solution is: A method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system, wherein a deoxygenated water supply pipeline, a heat pipe heat exchanger, a deoxygenated water return pipeline, a first pipeline monitoring system and a second pipeline monitoring system constitute a main loop, including: a parallel mixed water heating system; the parallel mixed water heating system comprises a first branch pipe, a mixed water pump, an electric regulating valve, a first gate valve, a second gate valve and a temperature recording interlock alarm; when water enters the deoxygenated water supply pipeline through the main loop, it enters the heat pipe heat exchanger through a check valve and a third gate valve, and the front end of the check valve is provided with a first pipeline monitoring system, when water is heat-exchanged through the flue gas in the heat pipe heat exchanger, it is discharged to the deoxygenated water return pipeline through a fourth gate valve, and the water return pipeline is provided with a second pipeline monitoring system and a temperature recording interlock alarm, thereby forming a closed loop; When the deaeration feed water return temperature is not higher than 95℃, the flue gas pipe temperature of the CDQ body inlet is lower than 115℃, the mixing water pump is started after a delay of 5s. When the mixing water pump is running and the flue gas inlet of the CDQ body is lower than 100℃, the electric regulating valve opening is set to 100%; When the water mixing pump is running, and the flue gas temperature at the CDQ body inlet is lower than 108°C and not lower than 100°C, the electric regulating valve opening is set to 80%; When the mixing pump operation signal is received, the electric regulating valve is interlocked and opened with a delay of 2s, and the opening of the electric regulating valve is set to 50%; When the return water temperature of deoxygenated feed water reaches 95℃, the mixing water pump will be shut down after a delay of 5s. After the running signal of the mixing water pump disappears, the electric regulating valve will be shut down after a delay of 2s. Wherein, the opening and closing of the water mixing pump and the electric regulating valve are both controlled by PLC.
[0006] Specifically, when the temperature of the flue gas pipeline at the CDQ body inlet is lower than the lower limit temperature of 115°C, the mixing water pump is turned on, and the mixing water pump will mix the part of the deoxygenated feed water return water that has not reached 95°C with the deoxygenated feed water supply water at 60°C; the mixed water is sent to the heat pipe heat exchanger again for secondary heat exchange; the deoxygenated feed water return flow threshold flowing through the mixing water pump is achieved by controlling the opening of the electric regulating valve through the temperature drop ratio of the CDQ body inlet flue gas pipeline, thereby ensuring that the water temperature entering the heat pipe heat exchanger reaches the expected value, while maintaining the temperature of the CDQ body inlet flue gas pipeline within a safe range; the temperature of the deoxygenated feed water supply water and part of the deoxygenated feed water return water increases after mixing, the flow rate remains unchanged, the heat exchange rate between the unit cold fluid and the circulating gas decreases, the deoxygenated feed water return water temperature increases, and the temperature of the CDQ body inlet flue gas pipeline increases, thereby preventing the occurrence of acid dew point corrosion.
[0007] In addition, the method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system in the above technical solution provided by the present invention may also have the following additional technical features: In the above technical scheme, there are a first pipeline monitoring system and a second pipeline monitoring system; the first pipeline monitoring system is arranged at the deoxygenated water supply pipeline, and the first pipeline monitoring system includes a first remote thermometer, a first on-site thermometer, a first on-site pressure gauge and a first remote pressure gauge; the second pipeline monitoring system is arranged at the deoxygenated water return pipeline, and the second pipeline monitoring system includes a second remote thermometer, a second on-site thermometer, a second on-site pressure gauge and a second remote pressure gauge.
[0008] In the above technical solution, the third gate valve is arranged between the deoxygenated water supply pipe and the water inlet of the heat pipe exchanger; the fourth gate valve is arranged between the deoxygenated water return pipe and the water outlet of the heat pipe exchanger.
[0009] The above technical solution also includes: a second branch pipe and a bypass valve; the two ends of the second branch pipe are respectively connected to the deoxygenated water supply pipeline and the deoxygenated water return pipeline; the bypass valve is arranged at the second branch pipe.
[0010] In the above technical solution, the check valve is arranged on the deoxygenated water supply pipeline.
[0011] The above technical solution also includes: a circulating fan and a reducer; the inlet of the circulating fan is connected to the CDQ secondary dust collector through a flue gas duct; the two ends of the reducer are respectively connected to the outlet of the circulating fan and the air inlet of the heat pipe exchanger.
[0012] In the above technical scheme, in order to prevent the mixing water pump from working for a long time, causing the return temperature of the deoxygenated feed water to be higher than the vaporization temperature of water, causing vibration of the heat pipe heat exchanger and causing safety hazards, the temperature recording interlock alarm on the deoxygenated feed water return pipe is interlocked with the mixing water pump. When the return temperature of the deoxygenated feed water is higher than 95°C, the mixing water pump is interlocked and shut down.
[0013] In the above technical solution, when the mixing water pump meets the start and stop conditions at the same time, the stop operation has a higher priority than the start operation.
[0014] Compared with the prior art, the method for recovering waste heat from flue gas of a non-operating dry quenching system of the present invention has the following beneficial effects: 1. By adding a first branch pipe, a mixing pump and an electric regulating valve between the deaerated water supply pipe and the deaerated water return pipe, and installing a temperature recording interlock alarm on the deaerated water return pipe, the waste heat of the CDQ circulating flue gas can be fully utilized to heat the deaerated water supply, ensuring that the deaerated water return temperature is maintained within a predetermined value, and ensuring that the temperature of the CDQ main body inlet flue gas pipe is within a safe range, preventing the CDQ main body inlet flue gas pipe from acid dew point corrosion.
[0015] 2. By adding the first gate valve and the second gate valve on both sides of the mixing pump to facilitate the maintenance of the mixing pump, the maintenance cost and downtime of the system are reduced.
[0016] 3. By combining the temperature recording interlock alarm and the pressure temperature monitoring system, the temperature and pressure changes in the system can be monitored in real time, thereby automatically adjusting the working status of the mixing pump and the opening of the electric control valve, improving the level of automation and operating efficiency.
[0017] 4. The combination of temperature recording interlock alarm and pressure temperature monitoring system improves the stability and reliability of the entire system under non-operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a structural schematic diagram of a method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to the present invention; Figure 2 This is a schematic diagram of the inlet and outlet flue gas pipe connection structure of the heat pipe heat exchanger of the present invention; in, Figure 1 to Figure 2 The corresponding relationship between the reference numerals and component names in the figure is: 10 deaerated water supply pipeline, 11 heat pipe heat exchanger, 12 deaerated water return pipeline, 13 first branch pipe, 14 mixing pump, 15 electric regulating valve, 16 temperature recording interlock alarm, 17 first remote thermometer, 18 first local thermometer, 19 first local pressure gauge, 20 first remote pressure gauge, 21 second remote thermometer, 22 second local thermometer, 23 second local pressure gauge, 24 second remote pressure gauge, 25 third gate valve, 26 fourth gate valve, 27 second branch pipe, 28 bypass valve, 29 first gate valve, 30 second gate valve, 31 check valve, 32 circulating fan, 33 reducer, 34 dry coke quenching secondary dust collector. DETAILED DESCRIPTION
[0019] The following is a combination of specific implementation cases and attached Figure 1-2 The present invention is further described below, but the present invention is not limited to these embodiments. Embodiment 1:
[0020] A method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system, wherein a deoxygenated water supply pipeline 10, a heat pipe heat exchanger 11, a deoxygenated water return pipeline 12, a first pipeline monitoring system and a second pipeline monitoring system constitute a main circuit. Figure 1-2As shown, it also includes: a parallel mixed water heating system; the parallel mixed water heating system includes a first branch pipe 13, a mixing water pump 14, an electric regulating valve 15, a first gate valve 29, a second gate valve 30 and a temperature recording interlock alarm 16, the two ends of the first branch pipe 13 are respectively connected to the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12, and the mixing water pump 14 and the electric regulating valve 15 are both arranged at the first branch pipe 13; the pressure and temperature monitoring systems are respectively arranged at the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12; the temperature recording interlock alarm 16 is arranged on the deoxygenated water return pipeline 12, and the temperature recording interlock alarm is located between the first branch pipe 13 and the heat pipe heat exchanger 11; When water enters the deoxygenated water supply pipe 10 through the main circuit, it enters the heat pipe heat exchanger 11 through the check valve 31 and the third gate valve 30, and the front end of the check valve 31 is provided with a first pipeline monitoring system. After the water passes through the flue gas in the heat pipe heat exchanger 11 for heat exchange, it is discharged to the deoxygenated water return pipe 12 through the fourth gate valve 26, and the deoxygenated water return pipe 12 is provided with a second pipeline monitoring system and a temperature recording interlock alarm 16, thereby forming a closed loop; When the deoxygenated feed water return temperature is not higher than 95℃, the flue gas pipe temperature of the CDQ body inlet is lower than 115℃, the mixing water pump 14 is started after a delay of 5s. When the mixing water pump 14 is running and the flue gas inlet of the CDQ body is lower than 100℃, the opening of the electric regulating valve 15 is set to 100%; When the water mixing pump 14 is running, and the flue gas temperature at the CDQ body inlet is lower than 108°C and not lower than 100°C, the opening of the electric regulating valve 15 is set to 80%; When the mixing water pump 14 receives the operation signal, the electric regulating valve 15 is opened after a delay of 2s, and the opening degree of the electric regulating valve 15 is set to 50%; When the return water temperature of the deoxygenated feed water reaches 95°C, the mixing water pump 14 is shut down by interlock after a delay of 5 seconds. After the operation signal of the mixing water pump 14 disappears, the electric regulating valve 15 is shut down by interlock after a delay of 2 seconds. The opening and closing of the mixing water pump 14 and the electric regulating valve 15 are both controlled by PLC.
[0021] Specifically, the water inlet of the heat pipe heat exchanger 11 is connected to the deoxygenated water supply pipeline 10 ; the deoxygenated water return pipeline 12 is connected to the water outlet of the heat pipe heat exchanger 11 .
[0022] By adopting the above technical scheme, a first branch pipe 13, a mixing pump 14 and an electric regulating valve 15 are added between the deoxygenated water supply pipe 10 and the deoxygenated water return pipe 12, and a temperature recording interlock alarm 16 is installed on the deoxygenated water return pipe 12, so as to fully utilize the waste heat of the CDQ circulating flue gas to heat the deoxygenated water supply, ensure that the deoxygenated water return temperature is maintained within a predetermined value, and ensure that the temperature of the CDQ main body inlet flue gas pipe is within a safe range, thereby preventing the CDQ main body inlet flue gas pipe from acid dew point corrosion; and by combining the temperature recording interlock alarm 16 with the pressure and temperature monitoring system, the temperature and pressure changes in the system can be monitored in real time, thereby automatically adjusting the working state of the mixing pump 14 and the opening of the electric regulating valve 15, thereby improving the automation level and operation efficiency.
[0023] By providing the first gate valve 29 and the second gate valve 30 , an operator can close the first and second gate valves, thereby facilitating maintenance or replacement of the water mixing pump 14 .
[0024] Specifically, the temperature recording interlock alarm 16 and the pressure and temperature monitoring system are used in combination to improve the stability and reliability of the entire system under non-operating conditions.
[0025] Specifically, for dry coke quenching systems with different processing capacities, the lift of the water mixing pump 14 is selected comprehensively based on the amount of circulating gas and the amount of deoxygenated water supply.
[0026] Specifically, by arranging the mixing water pump 14 at the inlet and outlet of the deoxygenated feed water supply and deoxygenated feed water return of the heat pipe heat exchanger 11, the pipeline has small resistance along the way, small pump head, and fast reaction speed. Under the premise of not affecting the normal operation of the dry coke quenching system, the waste heat of the dry coke quenching circulating gas is fully utilized to heat the deoxygenated feed water supply, ensure the deoxygenated feed water return temperature, and avoid acid dew point corrosion of the dry coke quenching body inlet pipeline. It effectively prevents improper operation of the operation and maintenance personnel during non-operating conditions, resulting in an imbalance of the steam-water ratio in the deoxygenation, a false liquid level in the deaerator, and the stop of the interlocking circulation fan and the boiler feed water pump.
[0027] In an embodiment of the present invention, Figure 1 As shown, the first pipeline monitoring system is arranged at the deoxygenated water supply pipeline 10, and the first pipeline monitoring system includes a first remote thermometer 17, a first on-site thermometer 18, a first on-site pressure gauge 19 and a first remote pressure gauge 20; the second pipeline monitoring system is arranged at the deoxygenated water return pipeline 12, and the second pipeline monitoring system includes a second remote thermometer 21, a second on-site thermometer 22, a second on-site pressure gauge 23 and a second remote pressure gauge 24.
[0028] By setting the first remote thermometer 17 and the second remote thermometer 21, the temperature data of the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12 are remotely transmitted respectively, so as to facilitate real-time monitoring by the central control system; by setting the first local thermometer 18 and the second local thermometer 22, the operating personnel can directly check the temperature of the supply water and the return water; the pressure of the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12 are respectively displayed by the first local pressure gauge 19 and the second local pressure gauge 23, so as to facilitate the operating personnel to understand the water supply pressure in time; the pressure data of the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12 are remotely transmitted by the first remote pressure gauge 20 and the second remote pressure gauge 24, so as to facilitate real-time monitoring by the central control system.
[0029] Specifically, in order to prevent the mixing water pump 14 from working for a long time, causing the return water temperature of the deoxygenated water to be higher than the vaporization temperature of water, thereby causing vibration of the heat pipe heat exchanger 11 and causing safety hazards, the second remote thermometer 21 on the deoxygenated water return pipe 12 is interlocked with the mixing water pump 14. When the return water temperature of the deoxygenated water is higher than 95°C, the mixing water pump 14 is interlocked and shut down. When the mixing water pump 14 meets the start and stop conditions at the same time, the stop operation has a higher priority than the start operation.
[0030] In an embodiment of the present invention, Figure 1 As shown, the third gate valve 25 is arranged between the deoxygenated water supply pipeline 10 and the water inlet of the heat pipe heat exchanger 11; the fourth gate valve 26 is arranged between the deoxygenated water return pipeline 12 and the water outlet of the heat pipe heat exchanger 11.
[0031] When inspection or maintenance is required, the heat pipe heat exchanger 11 is isolated from the deaerated water supply pipe 10 and the deaerated water return pipe 12 by closing the third gate valve 25 and the fourth gate valve 26 for safe operation, thereby preventing the accident from expanding.
[0032] In an embodiment of the present invention, it also includes: a second branch pipe 27 and a bypass valve 28; both ends of the second branch pipe 27 are respectively connected to the deoxygenated water supply pipeline 10 and the deoxygenated water return pipeline 12; the bypass valve 28 is arranged at the second branch pipe 27.
[0033] By providing the bypass valve 28 and the second branch pipe 27 , when a problem occurs in the heat exchange tube heat exchanger 11 , the supply water can flow through the second branch pipe 27 and be discharged.
[0034] In an embodiment of the present invention, Figure 1 As shown, the check valve 31 is arranged on the deoxygenated water supply pipeline 10 .
[0035] The check valve 31 is provided to prevent the water in the heat pipe heat exchanger 11 from flowing back to the deoxygenated water supply pipeline 10 .
[0036] In an embodiment of the present invention, Figure 2 As shown, it also includes: a circulating fan 32 and a reducing pipe 33; the inlet of the circulating fan 32 is connected to the CDQ secondary dust collector 34 through a flue gas duct; the two ends of the reducing pipe 33 are respectively connected to the outlet of the circulating fan 32 and the air inlet of the heat pipe heat exchanger 11.
[0037] The circulating fan 32 and the heat pipe heat exchanger 11 are connected via the reducer 33 so that the flue gas can smoothly enter the heat pipe heat exchanger 11 .
[0038] In an embodiment of the present invention, in order to prevent the mixing water pump from working for a long time, causing the return temperature of the deoxygenated feed water to be higher than the vaporization temperature of water, thereby causing vibration of the heat pipe exchanger and causing safety hazards, the temperature recording interlock alarm on the deoxygenated feed water return pipe is interlocked with the mixing water pump. When the return temperature of the deoxygenated feed water is higher than 95°C, the mixing water pump is interlocked and shut down.
[0039] In an embodiment of the present invention, when the water mixing pump satisfies both the start and stop conditions, the stop operation has a higher priority than the start operation. Embodiment 2:
[0040] There are three control methods for mixing water pumps: The first operation mode is on-site manual, which can control the start and stop of the mixing water pump through the machine side operation box.
[0041] The second operation mode is central manual, which can manually control the start and stop of the mixing water pump through the central control screen.
[0042] The third operation mode is central automatic, which can automatically control the start and stop of the mixing water pump through the central control program when certain conditions are met, and an interlock input / release switch button is provided on the control screen. When the return water temperature of the deaerator feed water is not higher than 95°C, and the temperature of the flue gas pipe at the inlet of the CDQ body is lower than 115°C, the interlock will be turned on with a delay of 5s; when the return water temperature of the deaerator feed water is higher than 95°C, the interlock will be turned off with a delay of 5s. Embodiment 3:
[0043] There are three control modes for electronically controlled regulating valves: The first operation mode is manual operation on site, where the switch is controlled by the actuator of the electric control valve head; The second operation mode is central manual, which manually controls the opening of the electronically controlled regulating valve through the central control screen; The third operation mode is central automatic. The central control program automatically controls the switch and opening size of the electric control valve when certain conditions are met, and an interlock input / release switch button is provided on the control screen. When the mixing water pump operation signal is received, the interlock opens the control valve with a delay of 2s, and the opening of the control valve is set to 50%; when the mixing water pump is running, the temperature of the flue gas duct at the inlet of the dry coke quenching body is lower than 108℃ and not lower than 100℃, and the opening is set to 80%; when the mixing water pump is running, the temperature of the flue gas duct at the inlet of the dry coke quenching body is lower than 100℃, and the opening is set to 100%; after the mixing water pump operation signal disappears, the interlock closes the control valve with a delay of 2s.
[0044] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention 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. Therefore, it cannot be understood as a limitation on the present invention. The terms "connection", "installation", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0045] In the description of the present invention, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the present invention, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system, wherein a deoxygenated water supply pipeline, a heat pipe heat exchanger, a deoxygenated water return pipeline, a first pipeline monitoring system and a second pipeline monitoring system constitute a main loop, characterized in that: include: A parallel mixed water heating system, the parallel mixed water heating system comprising a first branch pipe, a mixed water pump, an electric regulating valve, a first gate valve, a second gate valve and a temperature recording interlock alarm; When the deoxygenated water supply pipeline enters the heat pipe heat exchanger through the main circuit, the water passes through the check valve and the third gate valve, and the first pipeline monitoring system is provided at the front end of the check valve. After the water passes through the flue gas in the heat pipe heat exchanger, it is discharged to the deoxygenated water supply return pipeline through the fourth gate valve. The water supply return pipeline is provided with a second pipeline monitoring system and a temperature recording interlock alarm, thereby forming a closed loop. When the deaeration feed water return temperature is not higher than 95℃, the flue gas pipe temperature of the CDQ body inlet is lower than 115℃, the mixing water pump is started after a delay of 5s. When the mixing water pump is running and the flue gas inlet of the CDQ body is lower than 100℃, the electric regulating valve opening is set to 100%; When the water mixing pump is running, and the flue gas temperature at the CDQ body inlet is lower than 108°C and not lower than 100°C, the electric regulating valve opening is set to 80%; When the mixing pump operation signal is received, the electric regulating valve is interlocked and opened with a delay of 2s, and the opening of the electric regulating valve is set to 50%; When the return water temperature of deoxygenated feed water reaches 95℃, the mixing water pump will be shut down after a delay of 5s. After the running signal of the mixing water pump disappears, the electric regulating valve will be shut down after a delay of 2s. Wherein, the opening and closing of the water mixing pump and the electric regulating valve are both controlled by PLC.
2. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 1 is characterized in that: The first pipeline monitoring system is arranged at the deoxygenated water supply pipeline, and the first pipeline monitoring system includes a first remote thermometer, a first on-site thermometer, a first on-site pressure gauge and a first remote pressure gauge; The second pipeline monitoring system is arranged at the deoxygenated feed water return pipeline, and the second pipeline monitoring system includes a second remote thermometer, a second on-site thermometer, a second on-site pressure gauge and a second remote pressure gauge.
3. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 2 is characterized in that: The third gate valve is arranged between the deoxygenated water supply pipeline and the water inlet of the heat pipe heat exchanger; the fourth gate valve is arranged between the deoxygenated water return pipeline and the water outlet of the heat pipe heat exchanger.
4. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 3 is characterized in that: Also includes: A second branch pipe, both ends of which are respectively connected to the deoxygenated water supply pipe and the deoxygenated water return pipe; A bypass valve is arranged at the second branch pipe.
5. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 4 is characterized in that: The check valve is arranged on the deoxygenated water supply pipeline.
6. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 5 is characterized in that: Also includes: A circulating fan, wherein the inlet of the circulating fan is connected to the CDQ secondary dust collector through a flue gas duct; A reducer, both ends of which are respectively connected to the outlet of the circulation fan and the air inlet of the heat pipe exchanger.
7. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 6 is characterized in that: In order to prevent the mixing water pump from working for a long time, causing the return temperature of the deoxygenated feed water to be higher than the vaporization temperature of water, thereby causing vibration of the heat pipe exchanger and causing safety hazards, the temperature recording interlock alarm on the deoxygenated feed water return pipe is interlocked with the mixing water pump. When the return temperature of the deoxygenated feed water is higher than 95°C, the mixing water pump is interlocked and shut down.
8. The method for recovering waste heat from flue gas in a non-operating state of a dry coke quenching system according to claim 7 is characterized in that: When the mixing water pump meets both the start and stop conditions, the stop operation has a higher priority than the start operation.