A cooling system and method based on blast furnace tuyere small sleeve circulating water waste heat recovery

Abstract

The application provides a cooling system and method based on blast furnace tuyere small sleeve circulating water waste heat recovery, and belongs to the technical field of blast furnace ironmaking and energy recovery. The system comprises: a main circulating loop comprising a blast furnace main body cooling module, a main water return main pipe, a main heat exchanger group, a circulating water pump and a main water supply main pipe connected in circulation; a tuyere small sleeve branch is connected in parallel with the main circulating loop, an inlet is connected with the main water supply main pipe, and an outlet is connected with the main water return main pipe; a waste heat recovery branch comprises a water taking module, a degassing device, a heat exchanger and a water return module connected in sequence; the water taking module inlet is connected with the high-temperature water return pipe section of the tuyere small sleeve branch, the water return module outlet is connected with the main water return main pipe, and the heat exchanger secondary side is connected with an external heat utilization pipe network; when the branch is opened, the split high-temperature water return is mixed into the main water return main pipe after cooling, mixed with the blast furnace main body cooling module water return, and then enters the main heat exchanger group for cooling. The application realizes waste heat recovery and cooling cooperation, and ensures safety and energy saving.

Description

Technical Field

[0001] This application belongs to the field of blast furnace ironmaking and energy recovery technology, specifically relating to a cooling system and method based on waste heat recovery from circulating water in the blast furnace tuyeres. Background Technology

[0002] Blast furnace ironmaking is the core link in steel production, and the blast furnace cooling system is crucial for ensuring the safe and long-term operation of the blast furnace. Currently, large blast furnaces generally adopt a closed-loop soft water cooling system. The tuyeres are located in the area with the highest temperature and heat flux density inside the blast furnace, and their cooling return water temperature is usually the highest, reaching 47-50℃. It is the most valuable heat source for recovery in the cooling system.

[0003] However, existing blast furnace cooling systems have the following significant shortcomings in design and operation: First, the conflict between cooling capacity and smelting intensity is increasing. As the intensity of blast furnace smelting continues to rise, the load on the cooling system is constantly increasing. In summer or under special furnace conditions, the soft water return temperature has approached or exceeded the safety threshold. Traditional solutions often involve increasing the heat dissipation area of ​​the cooling tower or adding parallel plate radiators. This passive expansion method not only occupies a large area and involves high investment, but also faces cooling capacity bottlenecks in extreme weather or when space is limited. Second, it is difficult to balance waste heat recovery with the safe operation of the cooling system. The cooling water in the tuyeres is crucial to blast furnace safety. Current technology, which directly extracts heat from the main circulation loop, will disrupt the original hydraulic and thermal balance. If control fails, it could cause the blast furnace cooling water temperature to exceed the standard, seriously threatening production safety.

[0004] Therefore, there is an urgent need for an integrated technical solution that can efficiently recover waste heat from the vent jacket, actively enhance cooling capacity, and absolutely not affect the safety of the main system. Summary of the Invention

[0005] In a first aspect, embodiments of this application provide a cooling system based on waste heat recovery from circulating water in a blast furnace tuyeres, including a main circulation loop, a tuyeres branch, and a waste heat recovery and pre-cooling branch. The main circulation loop includes the blast furnace main cooling module, the main return water main, the main heat exchanger group, the circulating water pump and the main supply water main, which are connected in sequence. The tuyere branch circuit is connected in parallel with the main circulation circuit, and the inlet of the tuyere branch circuit is connected to the main water supply main pipe, while the outlet of the tuyere branch circuit is connected to the main return water main pipe. It is used to cool the blast furnace tuyere and generate high-temperature return water. The waste heat recovery and pre-cooling branch includes a water intake module, a degassing device, a waste heat recovery heat exchanger, and a return water module; the inlet of the water intake module is connected to the high-temperature return water pipe section of the air outlet branch; the outlet of the return water module is connected to the main return water main pipe of the main circulation loop, which is used to send the cooled circulating water back to the main return water main pipe; the secondary side of the waste heat recovery heat exchanger is connected to the external heat utilization network. Waste heat recovery and pre-cooling branch lines are selectively activated. When activated, the high-temperature return water diverted from the tuyer branch line is cooled by the waste heat recovery heat exchanger and then flows into the main return water main pipe through the return water module. It mixes with the return water from the blast furnace main cooling module and then enters the main heat exchanger group for secondary cooling.

[0006] Furthermore, the water intake point of the water intake module is set on the return water ring pipe of the tuyeres at the blast furnace body; Waste heat recovery heat exchangers can be plate heat exchangers, shell-and-tube heat exchangers, or coaxial heat exchangers.

[0007] Furthermore, it also includes a first valve group and a second valve group; The first valve group is installed on the inlet pipe of the water intake module to control the water flow rate entering the waste heat recovery and pre-cooling branch. The second valve assembly is installed on the original return water pipe of the small branch of the air outlet, and is used to cut off or reduce the flow rate through the original return water pipe when the waste heat recovery and pre-cooling branch is activated.

[0008] Furthermore, it also includes bypass pipelines; The bypass pipeline is connected in parallel to both ends of the primary side of the waste heat recovery heat exchanger and is equipped with a control valve. This valve is used to ensure that the high-temperature return water that is diverted returns directly to the main return water pipe without going through heat exchange when the waste heat recovery heat exchanger is under maintenance or when it is not in use for heating.

[0009] Secondly, embodiments of this application also provide a method for recovering and cooling waste heat from circulating water in a blast furnace tuyeres using the system described in the first aspect, comprising the following steps: S1. Monitor the return water temperature of the main circulation loop. When the return water temperature exceeds the preset safety threshold and / or there is a heat demand in the external heat utilization network, activate the waste heat recovery and pre-cooling branch. S2. Obtain diverted high-temperature return water from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module, and make the diverted high-temperature return water flow through the degassing device to remove the carried gas and complete the degassing. S3. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, so that it exchanges heat with the medium of the external heat utilization network flowing through the secondary side of the waste heat recovery heat exchanger, so that the temperature of the high-temperature return water is reduced from the initial temperature to the first-stage target temperature, and low-temperature circulating water is obtained. S4. The low-temperature circulating water cooled to the first-level target temperature is collected into the main return water pipe through the return water module and mixed with the return water of the blast furnace main cooling module to form mixed return water; S5. The mixed return water enters the main heat exchanger group, is further cooled to the final target supply water temperature, and then pressurized by the circulating water pump and supplied to the blast furnace main cooling module.

[0010] Furthermore, the specific steps of step S1 are as follows: S11. Real-time monitoring of the return water temperature of the main return water pipe. And obtain the total return water flow rate of the main circulation loop. Total return water flow of the small branch circuit at the air vent ; S12. When the return water temperature of the main return water pipe Exceeding the preset safety threshold When there is heat demand in the external heat utilization network, determine the diversion coefficient. :

[0011] in, Based on the basic diversion ratio, This is the proportional adjustment coefficient. This is the integral adjustment coefficient; S13. Based on the diversion coefficient Calculate the flow rates diverted to the waste heat recovery and pre-cooling branches. :

[0012] S14. Activate the waste heat recovery and pre-cooling branch to increase the diversion flow rate. The high-temperature return water is diverted from the small branch of the air vent into the water intake module.

[0013] Furthermore, the specific steps of step S2 are as follows: S21. Obtain sufficient diversion flow rate from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module. The high-temperature return water was diverted, and the initial temperature was measured. ; S22. The diverted high-temperature return water is introduced into the degassing device, and the gas entrained in the water is removed by vacuum degassing or mechanical exhaust. S23. Monitor the gas emissions from the degassing unit; When gas emissions are below the preset emission threshold, normal operation will continue. When the rate of change of gas emissions exceeds the preset rate of change threshold, an alarm is triggered and the system automatically switches to the bypass pipeline or shuts down the waste heat recovery and pre-cooling branch.

[0014] Furthermore, the specific steps of step S3 are as follows: S31. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, while the medium of the external heat utilization network flows through the secondary side. S32. Control the heat exchange process so that the temperature of the diverted high-temperature return water is reduced from the initial temperature. Reduce to the first target temperature ; S33. Calculate the recovered heat power using the following formula. To record the total amount of waste heat recovered and to perform energy-saving accounting;

[0015] in, The specific heat capacity of the circulating water. The density of the circulating water; S34. After heat exchange, the high-temperature return water is diverted to form low-temperature circulating water.

[0016] Furthermore, the specific steps of step S4 are as follows: S41. Obtain the main return water temperature of the blast furnace cooling wall and furnace bottom. and the total return water flow rate of the main circulation loop. ; S42. Set the cooled temperature to the primary target temperature. The low-temperature circulating water flows into the main return water pipe through the return water module, where it is at a temperature of... The main body of the return water mixes with the return water to form mixed return water; S43. Calculate the mixed return water temperature using the following formula. : .

[0017] Furthermore, the specific steps of step S5 are as follows: S51. Set the temperature to The mixed return water is fed into the main heat exchanger unit; S52. Heat exchange is performed between the main heat exchanger assembly and the industrial cooling water to further cool the mixed return water to the final target supply water temperature. ; S53. Calculate the required heat exchange capacity of the main heat exchanger assembly using the following formula. To record the cooling load of the main heat exchanger unit for subsequent system energy consumption monitoring or cooling capacity verification:

[0018] S54. Cool to the final target supply water temperature. The circulating water is pressurized by the circulating water pump and supplied to the main cooling module of the blast furnace and the small branch circuit of the tuyere.

[0019] As can be seen from the above technical solutions, this application has the following advantages: The cooling system and method based on waste heat recovery from the circulating water of the blast furnace tuyeres provided in this application extract heat from the return water of the tuyeres, which has the highest temperature, and transfer the heat to the external heat utilization network through a heat exchanger, thereby improving the comprehensive energy utilization rate of steel enterprises. By diverting high-temperature water for external heat exchange and cooling, and then reinjecting low-temperature water into the main return water pipe, the mixed water temperature entering the main heat exchanger group is reduced, which adds pre-cooling to the main circulation system and alleviates the cooling pressure in summer or under high load. By using parallel and selectively open waste heat recovery branches, with the water intake point located in the tuyeres branch and the return water point located in the main return water pipe, direct interference with the hydraulic balance of the blast furnace main cooling module is avoided, ensuring the safety of blast furnace cooling. The diversion coefficient is automatically adjusted according to the return water temperature and heat demand, realizing on-demand heat extraction and cooling, avoiding energy waste and system over-adjustment. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the cooling system based on the waste heat recovery of circulating water in the blast furnace tuyeres according to the present invention.

[0022] Figure 2 This is a schematic flowchart of the method for waste heat recovery and cooling of circulating water in the blast furnace tuyeres according to the present invention.

[0023] Among them, 1-Blast furnace main cooling module; 2-Main return water main pipe; 3-Main heat exchanger group; 4-Circulating water pump; 5-Main water supply main pipe; 6-Blast furnace tuyeres; 7-Water intake module; 8-Degassing device; 9-Waste heat recovery heat exchanger; 10-Return water module; 11-High temperature return water pipe section; 12-External heat utilization pipe network; 13-Cooling water circulation system. Detailed Implementation

[0024] The various embodiments of this disclosure will be described more fully in the cooling system based on waste heat recovery from circulating water in the blast furnace tuyeres, which will be described in detail below. This disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0025] This embodiment provides a cooling system based on waste heat recovery from circulating water in blast furnace tuyeres. The high-temperature return water in the branch tuyeres is used for heat exchange and extraction. After cooling, it is mixed into the main return water to achieve waste heat recovery and system cooling in a coordinated manner.

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1 The diagram shown is a schematic of a cooling system based on waste heat recovery from circulating water in a blast furnace tuyere jacket in a specific embodiment. The system includes a main circulation loop, a tuyere jacket branch, and a waste heat recovery and pre-cooling branch. The main circulation loop includes the blast furnace main cooling module 1, the main return water main pipe 2, the main heat exchanger group 3, the circulating water pump 4, and the main supply water main pipe 5, which are connected in sequence. The tuyere branch circuit is connected in parallel with the main circulation circuit, and the inlet of the tuyere branch circuit is connected to the main water supply main pipe 5, and the outlet of the tuyere branch circuit is connected to the main return water main pipe 2, which is used to cool the blast furnace tuyere 6 and generate high-temperature return water. The waste heat recovery and pre-cooling branch includes a water intake module 7, a degassing device 8, a waste heat recovery heat exchanger 9, and a return water module 10; the inlet of the water intake module 7 is connected to the high-temperature return water pipe section 11 of the air outlet branch; the outlet of the return water module 10 is connected to the main return water main pipe 2 of the main circulation loop, which is used to send the cooled circulating water back to the main return water main pipe 2; the secondary side of the waste heat recovery heat exchanger 9 is connected to the external heat utilization network 12; The water intake point of water intake module 7 is set on the return water ring pipe of the tuyeres at the blast furnace body; Waste heat recovery heat exchanger 9 adopts a plate heat exchanger, shell-and-tube heat exchanger, or coaxial heat exchanger. The waste heat recovery and pre-cooling branch can be selectively opened. When opened, the high-temperature return water flowing out from the tuyer branch is cooled by the waste heat recovery heat exchanger and then flows into the main return water pipe 2 through the return water module 10. It mixes with the return water of the blast furnace body cooling module 1 and then enters the main heat exchanger group 3 for secondary cooling. In the above system structure, the waste heat recovery and pre-cooling branch is independent of the main circulation loop. It only draws water from the high-temperature return water section of the tuyere branch, cools it through heat exchange, and then sends it back to the main return water main. Therefore, it does not change the hydraulic balance of the main circulation loop. At the same time, the operation of the waste heat recovery and pre-cooling branch is equivalent to adding a pre-cooler before the main heat exchanger group: the high-temperature return water first passes through the waste heat recovery heat exchanger 9 to release heat to the external heat utilization network 12. After the temperature is reduced, it is mixed with the return water of the blast furnace main cooling module 1, so that the temperature of the mixed return water entering the main heat exchanger group 3 is significantly lower than the return water temperature without the branch. This cooling structure of pre-cooling and main cooling in series not only recovers heat but also reduces the cooling load of the main heat exchanger group 3, realizing the synergistic effect of heat recovery and cooling load reduction. It should be noted that the main circulation loop of the blast furnace main cooling module 1, main return water main pipe 2, main heat exchanger group 3, circulating water pump 4, and main supply water main pipe 5 constitutes the basic closed loop of blast furnace cooling, ensuring the continuous and stable cooling of the blast furnace body and cooling wall. Since the vent sleeve is located in the area with the highest heat flux density, the vent sleeve branch connected in parallel to the main circulation loop is specially designed to handle the highest temperature return water. Its parallel connection with the main loop facilitates the centralized acquisition of high temperature heat sources, providing a high-quality heat medium for waste heat recovery. The water intake module 7 in the waste heat recovery and pre-cooling branch draws water from the high-temperature return water section, avoiding interference with the low-temperature water supply end and ensuring heat extraction efficiency; the degassing device 8 removes gas carried in the circulating water to prevent gas blockage or equipment corrosion, ensuring the heat exchange efficiency of the heat exchanger and the stable operation of the system; the waste heat recovery heat exchanger 9 realizes the isolation and exchange of heat between the high-temperature return water on the primary side and the external pipe network on the secondary side, which not only recovers heat but also lowers the temperature of the primary side water; the return water module 10 sends the cooled circulating water back to the main return water header 2, mixes it with the main return water, and plays the role of pre-cooling, reducing the load on the main heat exchanger group 3; the external heat utilization pipe network 12 provides an output channel for the recovered heat energy.

[0028] In this embodiment, the high-temperature return water from the diversion tuyeres is used for waste heat recovery. After cooling, it flows into the main return water pipe, effectively reducing the temperature of the main circulating water. This not only recovers high-grade heat energy but also enhances the cooling system capacity without affecting the safety of the blast furnace.

[0029] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process in this embodiment, another cooling system based on the waste heat recovery of circulating water in the blast furnace tuyeres is provided. This system includes a main circulation loop, a tuyeres branch, and a waste heat recovery and pre-cooling branch. The main circulation loop includes the blast furnace main cooling module 1, the main return water main pipe 2, the main heat exchanger group 3, the circulating water pump 4, and the main supply water main pipe 5, which are connected in sequence. The secondary side of the main heat exchanger group 3 is connected to the cooling water circulation system 13. After the industrial cooling water enters the main heat exchanger group 3 and absorbs the heat from the soft water, it is sent to the cooling tower of the cooling water circulation system 13 for cooling and then circulated back to the main heat exchanger group 3. The tuyere branch circuit is connected in parallel with the main circulation circuit, and the inlet of the tuyere branch circuit is connected to the main water supply main pipe 5, and the outlet of the tuyere branch circuit is connected to the main return water main pipe 2, which is used to cool the blast furnace tuyere 6 and generate high-temperature return water. The waste heat recovery and pre-cooling branch includes a water intake module 7, a degassing device 8, a waste heat recovery heat exchanger 9, and a return water module 10; the inlet of the water intake module 7 is connected to the high-temperature return water pipe section 11 of the air outlet branch; the outlet of the return water module 10 is connected to the main return water main pipe 2 of the main circulation loop, which is used to send the cooled circulating water back to the main return water main pipe 2; the primary side of the waste heat recovery heat exchanger 9 is connected to the degassing device 8 and the return water module 10, and the secondary side of the waste heat recovery heat exchanger 9 is connected to the external heat utilization network 12; Degassing device 8 adopts a vacuum degassing tank or an exhaust valve group; Waste heat recovery heat exchanger 9 adopts a plate heat exchanger, shell-and-tube heat exchanger, or coaxial heat exchanger. The external heat utilization network 12 is a winter heating network, a hot water network for driving absorption chillers, or a hot water network for industrial processes. Waste heat recovery and pre-cooling branch are selectively activated. When activated, the high-temperature return water flowing out from the tuyer branch is cooled by the waste heat recovery heat exchanger 9, and then flows into the main return water pipe 2 through the return water module 10. It mixes with the return water of the blast furnace main cooling module 1 and then enters the main heat exchanger group 3 for secondary cooling.

[0030] In some embodiments, unlike the embodiments described above, a first valve group and a second valve group are also included; The first valve group is installed on the inlet pipe of the water intake module 7 to control the water flow rate entering the waste heat recovery and pre-cooling branch. The second valve assembly is installed on the original return water pipe of the small branch of the air outlet, and is used to cut off or reduce the flow rate through the original return water pipe when the waste heat recovery and pre-cooling branch is activated.

[0031] Unlike some embodiments, and unlike the embodiments described above, a bypass pipeline is also included; The bypass pipeline is connected in parallel to both ends of the primary side of the waste heat recovery heat exchanger 9 and is equipped with a control valve to allow the high-temperature return water that flows out to return directly to the main return water main 2 without going through heat exchange when the waste heat recovery heat exchanger 9 is under maintenance or when it is not in use for heating.

[0032] like Figure 2As shown, the following are embodiments of the method for recovering and cooling waste heat from the circulating water of the blast furnace tuyeres provided in this disclosure. This method and the cooling system based on the recovery of waste heat from the circulating water of the blast furnace tuyeres in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the method for recovering and cooling waste heat from the circulating water of the blast furnace tuyeres, please refer to the embodiments of the cooling system based on the recovery of waste heat from the circulating water of the blast furnace tuyeres.

[0033] The method includes the following steps: S1. Monitor the return water temperature of the main circulation loop. When the return water temperature exceeds the preset safety threshold and / or there is a heat demand in the external heat utilization network, activate the waste heat recovery and pre-cooling branch. It should be noted that this step is based on a dual judgment of temperature threshold and heat demand, ensuring that it is only activated when cooling is needed or when there are users with heat, thus guaranteeing the economy and necessity of operation. S2. Obtain diverted high-temperature return water from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module, and make the diverted high-temperature return water flow through the degassing device to remove the carried gas and complete the degassing. It should be noted that pre-treatment of the diverted high-temperature water by degassing can effectively prevent scaling, corrosion and air lock in the subsequent heat exchanger, thus ensuring heat exchange efficiency. S3. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, so that it exchanges heat with the medium of the external heat utilization network flowing through the secondary side of the waste heat recovery heat exchanger, so that the temperature of the high-temperature return water is reduced from the initial temperature to the first-stage target temperature, and low-temperature circulating water is obtained. It should be noted that this step is the core heat recovery process. The high-temperature return water releases heat to the external pipe network in the heat exchanger, and its own temperature drops to the first-stage target temperature, thus realizing the cascade utilization of thermal energy. S4. The low-temperature circulating water cooled to the first-level target temperature is collected into the main return water pipe through the return water module and mixed with the return water of the blast furnace main cooling module to form mixed return water; It should be noted that in this step, the cooled low-temperature circulating water is collected into the main return water pipe and mixed with the lower-temperature main return water, thereby reducing the water temperature entering the next stage of cooling equipment. S5. The mixed return water enters the main heat exchanger group, is further cooled to the final target supply water temperature, and then pressurized by the circulating water pump and supplied to the blast furnace main cooling module. It should be noted that this step allows the mixed water to enter the main heat exchanger unit for final cooling. Due to the pre-cooling process, the heat load of the main heat exchanger unit is significantly reduced, making it easier to lower the water temperature to the final target supply water temperature, thereby ensuring that the cooling water temperature supplied to the blast furnace is always within a safe range.

[0034] This embodiment uses a parallel branch to extract high-temperature return water from the small tuyeres. After heat exchange and waste heat recovery, the low-temperature water is mixed into the main circuit to achieve pre-cooling. This not only makes efficient use of thermal energy but also reduces the cooling load on the main heat exchanger group, ensuring the safe operation of the blast furnace and achieving energy saving and efficiency improvement.

[0035] This application enables the synergy of waste heat recovery and pre-cooling, as specifically demonstrated below: Waste heat recovery and pre-cooling branches are independently switched on and off via valve assemblies. During normal operation, they can be flexibly activated or deactivated according to the blast furnace heat load and external heat demand. When deactivated, the system returns to its original cooling mode, ensuring the blast furnace remains unaffected under any operating conditions. The water intake point is located on the high-temperature return water section of the tuyeres branch, rather than the main return water main, avoiding direct disturbance to the water flow of the blast furnace main cooling module during diversion operations. Simultaneously, the return water point is located on the main return water main, where the cooled low-temperature circulating water mixes with the main return water before entering the main heat exchanger assembly, forming a thermal series structure of mixing followed by cooling. This recovers heat while reducing the load on the main heat exchanger assembly. The degassing device ensures the airtightness of the soft water closed-loop circulation system; the bypass pipeline provides a direct path during non-heating or maintenance periods; and the valve assembly allows for rapid return to the original circuit, ensuring uninterrupted blast furnace cooling.

[0036] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process in this embodiment, another method for waste heat recovery and cooling of circulating water in the blast furnace tuyeres is provided. This method includes the following steps: S1. Monitor the return water temperature of the main circulation loop. When the return water temperature exceeds the preset safety threshold and / or there is a heat demand in the external heat utilization network, activate the waste heat recovery and pre-cooling branch. The specific steps of step S1 are as follows: S11. Real-time monitoring of the return water temperature of the main return water pipe. And obtain the total return water flow rate of the main circulation loop. Total return water flow of the small branch circuit at the air vent ; S12. When the return water temperature of the main return water pipe Exceeding the preset safety threshold When there is heat demand in the external heat utilization network, determine the diversion coefficient. :

[0037] in, Based on the basic diversion ratio, This is the proportional adjustment coefficient. This is the integral adjustment coefficient; S13. Based on the diversion coefficient Calculate the flow rates diverted to the waste heat recovery and pre-cooling branches. :

[0038] S14. Activate the waste heat recovery and pre-cooling branch to increase the diversion flow rate. The high-temperature return water is diverted from the small branch of the air vent into the water intake module; In actual operation, the diversion coefficient determined in step S1 It is not a fixed value, but rather based on the actual measured temperature of the main return water pipe. With preset safety threshold The deviation is dynamically adjusted using a proportional-integral control law; where the proportional term... Achieving rapid response, integral items Eliminating steady-state errors; the final flow split coefficient is limited to between 0.3 and 1.0, ensuring that at least 30% of the small-scale return water enters the main return water pipe at any time, thus maintaining the hydraulic stability of the original system and not exceeding 100% to avoid excessive water intake; this dynamic control algorithm enables the system to automatically match the heat intake intensity according to changes in heat load, avoiding both excessive cooling that leads to energy waste and insufficient heat intake that causes the main return water temperature to exceed the standard. S2. Obtain diverted high-temperature return water from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module, and make the diverted high-temperature return water flow through the degassing device to remove the carried gas and complete the degassing. The specific steps of step S2 are as follows: S21. Obtain sufficient diversion flow rate from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module. The high-temperature return water was diverted, and the initial temperature was measured. ; S22. The diverted high-temperature return water is introduced into the degassing device, and the gas entrained in the water is removed by vacuum degassing or mechanical exhaust. S23. Monitor the gas emissions from the degassing unit; When gas emissions are below the preset emission threshold, normal operation will continue. When the rate of change of gas emissions exceeds the preset rate of change threshold, an alarm is triggered and the system automatically switches to the bypass pipeline or shuts down the waste heat recovery and pre-cooling branch. It should be noted that the following steps are included before step S21: S20. Before starting the waste heat recovery and pre-cooling branch, start the degassing device to pre-ventilate until the gas emission is lower than the preset threshold. S3. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, so that it exchanges heat with the medium of the external heat utilization network flowing through the secondary side of the waste heat recovery heat exchanger, so that the temperature of the high-temperature return water is reduced from the initial temperature to the first-stage target temperature, and low-temperature circulating water is obtained. The specific steps of step S3 are as follows: S31. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, while the medium of the external heat utilization network flows through the secondary side. S32. Control the heat exchange process so that the temperature of the diverted high-temperature return water is reduced from the initial temperature. Reduce to the first target temperature ,in, The value range is 35℃~40℃; S33. Calculate the recovered heat power using the following formula. To record the total amount of waste heat recovered and to perform energy-saving accounting;

[0039] in, The specific heat capacity of the circulating water. The density of the circulating water; S34. After heat exchange, the high-temperature return water is diverted to form low-temperature circulating water; S4. The low-temperature circulating water cooled to the first-level target temperature is collected into the main return water pipe through the return water module and mixed with the return water of the blast furnace main cooling module to form mixed return water; The specific steps of step S4 are as follows: S41. Obtain the main return water temperature of the blast furnace cooling wall and furnace bottom. and the total return water flow rate of the main circulation loop. (in ≥ ); S42. Set the cooled temperature to the primary target temperature. The low-temperature circulating water flows into the main return water pipe through the return water module, where it is at a temperature of... The main body of the return water mixes with the return water to form mixed return water; S43. Calculate the mixed return water temperature using the following formula. : ; S5. The mixed return water enters the main heat exchanger group, is further cooled to the final target supply water temperature, and then pressurized by the circulating water pump and supplied to the blast furnace main cooling module. The specific steps of step S5 are as follows: S51. Set the temperature to The mixed return water is fed into the main heat exchanger unit; S52. Heat exchange is performed between the main heat exchanger assembly and the industrial cooling water to further cool the mixed return water to the final target supply water temperature. ; S53. Calculate the required heat exchange capacity of the main heat exchanger assembly using the following formula. To record the cooling load of the main heat exchanger unit for subsequent system energy consumption monitoring or cooling capacity verification:

[0040] S54. Cool to the final target supply water temperature. The circulating water is pressurized by the circulating water pump and supplied to the main cooling module of the blast furnace and the small branch circuit of the tuyere.

[0041] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0042] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cooling system based on waste heat recovery from circulating water in a blast furnace tuyeres, characterized in that, This includes the main circulation loop, the small branch loop of the air outlet, and the waste heat recovery and pre-cooling branch loop; The main circulation loop includes the blast furnace main cooling module, the main return water main, the main heat exchanger group, the circulating water pump and the main supply water main, which are connected in sequence. The tuyere branch circuit is connected in parallel with the main circulation circuit, and the inlet of the tuyere branch circuit is connected to the main water supply main pipe, while the outlet of the tuyere branch circuit is connected to the main return water main pipe. It is used to cool the blast furnace tuyere and generate high-temperature return water. The waste heat recovery and pre-cooling branch includes a water intake module, a degassing device, a waste heat recovery heat exchanger, and a return water module; the inlet of the water intake module is connected to the high-temperature return water pipe section of the air outlet branch; the outlet of the return water module is connected to the main return water main pipe of the main circulation loop, which is used to send the cooled circulating water back to the main return water main pipe; the secondary side of the waste heat recovery heat exchanger is connected to the external heat utilization network. Waste heat recovery and pre-cooling branch lines are selectively activated. When activated, the high-temperature return water diverted from the tuyer branch line is cooled by the waste heat recovery heat exchanger and then flows into the main return water main pipe through the return water module. It mixes with the return water from the blast furnace main cooling module and then enters the main heat exchanger group for secondary cooling.

2. The cooling system based on waste heat recovery from circulating water in the blast furnace tuyeres as described in claim 1, characterized in that, The water intake point of the water intake module is set on the return water ring pipe of the tuyeres at the blast furnace body; Waste heat recovery heat exchangers can be plate heat exchangers, shell-and-tube heat exchangers, or coaxial heat exchangers.

3. The cooling system based on waste heat recovery from circulating water in the blast furnace tuyeres as described in claim 1, characterized in that, It also includes the first valve group and the second valve group; The first valve group is installed on the inlet pipe of the water intake module to control the water flow rate entering the waste heat recovery and pre-cooling branch. The second valve assembly is installed on the original return water pipe of the small branch of the air outlet, and is used to cut off or reduce the flow rate through the original return water pipe when the waste heat recovery and pre-cooling branch is activated.

4. The cooling system based on waste heat recovery from circulating water in the blast furnace tuyeres as described in claim 1, characterized in that, It also includes bypass pipelines; The bypass pipeline is connected in parallel to both ends of the primary side of the waste heat recovery heat exchanger and is equipped with a control valve. This valve is used to ensure that the high-temperature return water that is diverted returns directly to the main return water pipe without going through heat exchange when the waste heat recovery heat exchanger is under maintenance or when it is not in use for heating.

5. A method for recovering and cooling waste heat from circulating water in a blast furnace tuyeres using the system described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Monitor the return water temperature of the main circulation loop. When the return water temperature exceeds the preset safety threshold and / or there is a heat demand in the external heat utilization network, activate the waste heat recovery and pre-cooling branch. S2. Obtain diverted high-temperature return water from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module, and make the diverted high-temperature return water flow through the degassing device to remove the carried gas and complete the degassing. S3. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, so that it exchanges heat with the medium of the external heat utilization network flowing through the secondary side of the waste heat recovery heat exchanger, so that the temperature of the high-temperature return water is reduced from the initial temperature to the first-stage target temperature, and low-temperature circulating water is obtained. S4. The low-temperature circulating water cooled to the first-level target temperature is collected into the main return water pipe through the return water module and mixed with the return water of the blast furnace main cooling module to form mixed return water; S5. The mixed return water enters the main heat exchanger group, is further cooled to the final target supply water temperature, and then pressurized by the circulating water pump and supplied to the blast furnace main cooling module.

6. The method for waste heat recovery and cooling of circulating water in blast furnace tuyeres according to claim 5, characterized in that, The specific steps of step S1 are as follows: S11. Real-time monitoring of the return water temperature of the main return water pipe. And obtain the total return water flow rate of the main circulation loop. Total return water flow of the small branch circuit at the air vent ; S12. When the return water temperature of the main return water pipe Exceeding the preset safety threshold When there is heat demand in the external heat utilization network, determine the diversion coefficient. : in, Based on the basic diversion ratio, This is the proportional adjustment coefficient. This is the integral adjustment coefficient; S13. Based on the diversion coefficient Calculate the flow rates diverted to the waste heat recovery and pre-cooling branches. : S14. Activate the waste heat recovery and pre-cooling branch to increase the diversion flow rate. The high-temperature return water is diverted from the small branch of the air vent into the water intake module.

7. The method for waste heat recovery and cooling of circulating water in blast furnace tuyeres according to claim 6, characterized in that, The specific steps of step S2 are as follows: S21. Obtain sufficient diversion flow rate from the high-temperature return water pipe section of the small branch of the air outlet through the water intake module. The high-temperature return water was diverted, and the initial temperature was measured. ; S22. The diverted high-temperature return water is introduced into the degassing device, and the gas entrained in the water is removed by vacuum degassing or mechanical exhaust. S23. Monitor the gas emissions from the degassing unit; When gas emissions are below the preset emission threshold, normal operation will continue. When the rate of change of gas emissions exceeds the preset rate of change threshold, an alarm is triggered and the system automatically switches to the bypass pipeline or shuts down the waste heat recovery and pre-cooling branch.

8. The method for waste heat recovery and cooling of circulating water in blast furnace tuyeres according to claim 7, characterized in that, The specific steps of step S3 are as follows: S31. The degassed high-temperature return water is fed into the primary side of the waste heat recovery heat exchanger, while the medium of the external heat utilization network flows through the secondary side. S32. Control the heat exchange process so that the temperature of the diverted high-temperature return water is reduced from the initial temperature. Reduce to the first target temperature ; S33. Calculate the recovered heat power using the following formula. To record the total amount of waste heat recovered and to perform energy-saving accounting; in, The specific heat capacity of the circulating water. The density of the circulating water; S34. After heat exchange, the high-temperature return water is diverted to form low-temperature circulating water.

9. The method for waste heat recovery and cooling of circulating water in blast furnace tuyeres according to claim 5, characterized in that, The specific steps of step S4 are as follows: S41. Obtain the main return water temperature of the blast furnace cooling wall and furnace bottom. and the total return water flow rate of the main circulation loop. ; S42. Set the cooled temperature to the primary target temperature. The low-temperature circulating water flows into the main return water pipe through the return water module, where it is at a temperature of... The main body of the return water mixes with the return water to form mixed return water; S43. Calculate the mixed return water temperature using the following formula. : 。 10. The method for waste heat recovery and cooling of circulating water in blast furnace tuyeres according to claim 5, characterized in that, The specific steps of step S5 are as follows: S51. Set the temperature to The mixed return water is fed into the main heat exchanger unit; S52. Heat exchange is performed between the main heat exchanger assembly and the industrial cooling water to further cool the mixed return water to the final target supply water temperature. ; S53. Calculate the required heat exchange capacity of the main heat exchanger assembly using the following formula. To record the cooling load of the main heat exchanger unit for subsequent system energy consumption monitoring or cooling capacity verification: S54. Cool to the final target supply water temperature. The circulating water is pressurized by the circulating water pump and supplied to the main cooling module of the blast furnace and the small branch circuit of the tuyere.

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