Safety protection system and method for heat storage regulating furnace

Abstract

The safety protection system comprises a monitoring device, an air supply device and a controller, the monitoring device is used for detecting the temperature in the heat storage adjusting furnace, the air supply device comprises an air supply pipeline, a spray gun and air supply equipment, the spray gun is installed on the top or the side portion of the heat storage adjusting furnace so as to spray cooling gas into the furnace, and the air supply equipment is installed on the air supply pipeline. One end of the air supply pipeline is connected with the spray gun, the other end of the air supply pipeline is connected with the air supply equipment, an adjusting valve group is arranged on the air supply pipeline, the adjusting valve group and the monitoring device are respectively in signal connection with the controller, and the controller receives an in-furnace temperature detection value of the monitoring device and compares the in-furnace temperature detection value with a set temperature; automatically controlling the opening degree of the regulating valve group to input cooling gas into the furnace for cooling; the furnace temperature is monitored through smoke temperature detection so as to adjust the flow of the blown-in cooling gas in an interlocking mode, the furnace temperature of the heat storage adjusting furnace does not exceed the upper limit value, and explosion in the heat storage adjusting furnace is avoided.

Description

Technical Field

[0001] This invention relates to the field of recycled copper refining technology, specifically a safety protection system and method for a regenerative regulating furnace. Background Technology

[0002] Patent document CN114608331B, entitled "A Heat Preservation and Furnace Drying Device and Method," discloses a method of setting up a regenerative regulating furnace between two fixed anode furnaces, with the two fixed anode furnaces connected to the regenerative regulating furnace via a connecting flue. By adjusting the amount of flue gas entering the regenerative regulating furnace from the operating fixed anode furnace through its outlet, and adjusting the amount of flue gas entering the standby fixed anode furnace from the regenerative regulating furnace, the high-temperature flue gas generated by the operating fixed anode furnace continuously heats and preserves the temperature of the standby fixed anode furnace, and performs a preliminary drying process. This keeps the temperature inside the standby fixed anode furnace consistently high. When enterprises need to expand production, they can reduce the drying time of the standby fixed anode furnace, allowing it to be put into production more quickly.

[0003] The regenerative regulating furnace serves as a heat storage and buffer, reducing temperature fluctuations in high-temperature flue gas. It effectively controls the heating of the standby fixed anode furnace by the high-temperature flue gas, preventing excessively drastic temperature rises and falls in the standby fixed anode furnace. During production, the temperature of the regenerative regulating furnace is controlled between 500℃ and 700℃, while the temperature inside the standby fixed anode furnace is controlled between 400℃ and 500℃. During operation, 10%–30% of the flue gas generated by the fixed anode furnace (referred to as bypass flue gas) enters the regenerative regulating furnace, with most of it then entering the standby fixed anode furnace. The remaining 70%–90% of the flue gas (referred to as main flue gas) experiences a temperature drop of 100℃–300℃, reducing the operating costs of the flue gas cooling equipment. The main flue gas follows the same flow direction as the conventional fixed anode furnace flue gas: it first enters the furnace tail flue, then the exhaust system, and is sent to a bag filter for purification.

[0004] In practical applications, this patented technology has the following problems: In the reduction process, the fixed anode furnace uses natural gas as a reducing agent in the molten copper. After reduction, the remaining natural gas enters the furnace chamber. Due to the slightly positive pressure control during reduction, very little outside air leaks into the fixed anode furnace, creating an oxygen-deficient environment. This means that the amount of oxygen needed to support the combustion of the remaining natural gas is insufficient. Therefore, some of the remaining natural gas reacts fully with oxygen and burns completely to produce CO2; some does not come into contact with enough oxygen and produces CO; and a small portion of the natural gas does not come into contact with oxygen and directly enters the flue gas. Since CH4 accounts for 97% of the natural gas, this results in the simultaneous presence of CO and CH4 in the flue gas from the fixed anode furnace.

[0005] Then, the main flue gas enters the tail flue, which operates under negative pressure. Outside air is drawn into the flue, aiding the combustion of residual CO and CH4 in the flue gas. Furthermore, the flue gas temperature is 900℃~1100℃, far exceeding the ignition point of CO and CH4, causing them to burn rapidly and completely convert into CO2. Therefore, CO and CH4 cannot be detected in the flue gas at the inlet of the bag filter.

[0006] The bypass flue gas enters the regenerative regulating furnace. Since the temperature of the regenerative regulating furnace is only 600℃~700℃ at this time, which is close to the ignition temperature of CO and CH4, CO and CH4 cannot be burned immediately. When the regenerative regulating furnace forms a relatively closed space, CO and CH4 are ignited by sparks in the flue gas and explode with the help of air drawn in from the outside. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a safety protection system and method for a regenerative regulating furnace.

[0008] The specific solution of the present invention is as follows: A safety protection system for a thermal regenerative regulating furnace includes a monitoring device, an air supply device, and a controller. The monitoring device is used to detect the temperature inside the thermal regenerative regulating furnace. The air supply device includes an air supply pipeline, a spray gun, and an air supply device. The spray gun is installed on the top or side of the thermal regenerative regulating furnace to spray cooling gas into the furnace. One end of the air supply pipeline is connected to the spray gun, and the other end is connected to the air supply device. A regulating valve group is provided on the air supply pipeline. The regulating valve group and the monitoring device are respectively connected to the controller. The controller receives the furnace temperature detection value from the monitoring device and compares it with the set temperature. It automatically controls the opening of the regulating valve group to input cooling gas into the furnace for cooling.

[0009] Furthermore, the cooling gas is compressed air or nitrogen.

[0010] Furthermore, the air supply duct is equipped with a pressure regulating device, which is used to adjust the gas pressure entering the spray gun.

[0011] Furthermore, the spray gun includes a circular tube, one end of which is inserted into the furnace and fitted with a swirl vane. The swirl vane is used to cause the cooling gas to enter the regenerative regulating furnace in a swirling manner.

[0012] Furthermore, the spray gun is equipped with a spray gun holder, which is fixedly connected to the heat storage regulating furnace. The spray gun holder has a mounting hole, through which the spray gun is inserted into the heat storage regulating furnace.

[0013] Furthermore, the regulating valve assembly includes a pneumatic switching valve, a pneumatic regulating valve, and a flow meter; the monitoring device employs a temperature measuring thermocouple.

[0014] Furthermore, the present invention also provides a safety protection method for a regenerative regulating furnace, employing the aforementioned regenerative regulating furnace safety protection system, specifically including the following steps: after the anode furnace begins reduction operation, the air supply pipeline is opened to prepare to input cooling gas into the regenerative regulating furnace; the controller receives the temperature value detected by the monitoring device and compares it with the furnace temperature setpoint: if the temperature value is higher than the furnace temperature setpoint, the controller interlocks and opens the regulating valve group of the air supply pipeline to input cooling gas into the spray gun; when the temperature value is lower than the furnace temperature setpoint, the controller interlocks and closes the regulating valve group of the air supply pipeline to stop inputting cooling gas into the spray gun.

[0015] Furthermore, the monitoring device employs multiple sets to detect the temperature at different locations. The controller calculates the average value of the temperature values ​​monitored by the multiple sets of monitoring devices and compares it with the furnace temperature setpoint. Based on the magnitude of the deviation, the controller controls the opening of the regulating valve group to adjust the flow rate of cooling gas in the air supply pipeline, thereby regulating the cooling rate.

[0016] The reason for employing the above-mentioned technical means in this invention is as follows: The inventors noticed that the regenerative regulating furnace never exploded during non-reduction operations of the fixed anode furnace, and therefore conducted further research. Initial research suggested that the main reason was the relatively low temperature of the regenerative regulating furnace during this operation phase, only 500℃~600℃, thus preventing explosions similar to those of the standby fixed anode furnace. However, compared to reduction operations, the temperature difference in the regenerative regulating furnace is not significant, so the conclusion that the relatively low temperature is the main factor preventing explosions is questionable.

[0017] Further research by the inventors revealed that the flue gas regulating gates at the inlet and outlet of the regenerative regulating furnace remained open during non-reduction operations, with a minimum opening degree greater than 10%. This meant that a relatively enclosed space was not formed inside the regenerative regulating furnace, which was the more important reason why an explosion did not occur. The gates remained open because, during non-reduction operations, the flue gas temperature in the fixed anode furnace was much lower. The flue gas regulating gates at the inlet and outlet of the regenerative regulating furnace needed to maintain a large opening to introduce more bypass flue gas, thereby maintaining the temperature inside the regenerative regulating furnace at 500℃~600℃ and keeping the temperature inside the standby fixed anode furnace at no less than 400℃.

[0018] In view of this, the inventors envisioned a low-cost temperature control method that, during reduction operations, would allow the temperature of the regenerative thermal regulator to be reduced to 600℃~700℃, or even 500℃~600℃, while simultaneously maintaining the flue gas regulating gates at the inlet and outlet of the regenerative thermal regulator at an opening of more than 10%, ensuring a continuous flow of flue gas into and out of the regenerative thermal regulator. In this way, the regenerative thermal regulator would neither exceed its temperature limit nor form a relatively confined space, thus preventing an explosion.

[0019] Compared with the prior art, the present invention has the following beneficial effects: by monitoring the furnace temperature through flue gas temperature detection, the flow rate of the injected cooling gas is interlocked and adjusted so that the furnace temperature of the regenerator does not exceed the upper limit value. At the same time, it ensures that the flue gas regulating gates at the inlet and outlet of the regenerator are always kept at a certain opening, so that the flue gas flows smoothly in and out of the regenerator and does not form a relatively closed space, thereby avoiding the occurrence of explosion. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the system structure of Embodiment 1 of the present invention;

[0021] Figure 2 This is a schematic diagram of the system structure of Embodiment 2 of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the spray gun of the present invention;

[0023] Figure 4 This is a comparative structural schematic diagram of the present invention;

[0024] In the diagram: 1. Regenerative regulating furnace; 2. Spray gun holder; 3. Spray gun; 31. Circular tube; 32. Swirl vane; 33. Spray gun regulating valve; 4. Temperature measuring thermocouple; 5. Pneumatic switch valve; 6. Controller; 7. Manual regulating valve; 8. Air supply pipeline; 9. Pressure regulating device; 10. Nitrogen storage tank; 11. Pressure gauge; 12. Flow meter; 13. Pneumatic regulating valve; 14. Fan; 15. Gate. Detailed Implementation

[0025] Example 1

[0026] See Figure 1 , Figure 3This embodiment provides a safety protection system for a thermal regenerative regulating furnace 1, including a monitoring device, an air supply device, and a controller 6. The monitoring device is used to detect the temperature inside the thermal regenerative regulating furnace 1. The air supply device includes an air supply pipe 8, a spray gun 3, and air supply equipment. The spray gun 3 is installed on the top or side of the thermal regenerative regulating furnace 1 to spray cooling gas into the furnace. One end of the air supply pipe 8 is connected to the spray gun 3, and the other end is connected to the air supply equipment. A regulating valve group is provided on the air supply pipe 8. The regulating valve group and the monitoring device are respectively connected to the controller 6. The controller 6 receives the furnace temperature detection value from the monitoring device and compares it with the set temperature, automatically controlling the opening of the regulating valve group to input cooling gas into the furnace for cooling. Further, the air supply equipment uses a nitrogen storage tank 10, and the cooling gas uses nitrogen. Furthermore, the air supply pipeline 8 is equipped with a pressure regulating device 9, which uses a gas source triplet to reduce the nitrogen pressure to below 0.05 MPa before inputting it into the air supply pipeline 8. Pressure gauges 11 are installed at both the inlet and outlet of the pressure regulating device 9. Furthermore, the spray gun 3 includes a circular tube 31, with a swirl vane 32 installed at one end of the tube inserted into the furnace. The swirl vane 32 is used to cause the cooling gas to enter the regenerative regulating furnace 1 in a swirling manner. Furthermore, the spray gun 3 is equipped with a spray gun seat 2, which is fixedly connected to the regenerative regulating furnace 1. The spray gun seat 2 has mounting holes through which the spray gun 3 is inserted into the regenerative regulating furnace 1. Furthermore, the regulating valve group includes a pneumatic switch valve 5, a pneumatic regulating valve 13, and a flow meter 12; the monitoring device uses a temperature measuring thermocouple 4. In this embodiment, the specific steps include: after the anode furnace begins reduction operation, the air supply pipeline 8 is opened to prepare to input cooling gas into the regenerative regulating furnace 1; the controller 6 receives the temperature value detected by the monitoring device and compares it with the furnace temperature setpoint: if the temperature value is higher than the furnace temperature setpoint, the controller 6 interlocks and opens the regulating valve group of the air supply pipeline 8 to input cooling gas into the spray gun 3; when the temperature value is lower than the furnace temperature setpoint, the controller 6 interlocks and closes the regulating valve group of the air supply pipeline 8 to stop inputting cooling gas into the spray gun 3. Based on the values ​​of the flow meter 12 and the thermocouple 4, the opening of the manual regulating valve 7 is changed to adjust the total nitrogen input to 300 m³ / h to 800 m³ / h, so that the actual temperature of the regenerative regulating furnace 1 matches the furnace temperature setpoint, while saving nitrogen consumption. The opening of the manual switch valve at the inlet of the spray gun 3 is adjusted to adjust the nitrogen flow rate of the spray gun 3. Typically, the opening of the manual switch valve on the inlet side of the regenerative regulating furnace 1 is greater than that on the outlet side of the spray gun 3. During the reduction operation of the fixed anode furnace, the flue gas regulating gates 15 at the inlet and outlet of the regenerative regulating furnace 1 are maintained at 15% opening. Practical application of this embodiment shows that the regenerative regulating furnace 1 did not explode, meeting safety production requirements. However, this solution is predicated on the availability of a nearby oxygen production facility to supply pipeline nitrogen, with nitrogen costing less than 0.1 yuan / m³; otherwise, it is uneconomical. When using pipeline nitrogen, the large nitrogen consumption of the safety device in the regenerative regulating furnace 1 negatively impacts the gas supply pressure and flow rate of instruments without a gas manifold.If a company does not have a pipeline nitrogen source and needs to produce nitrogen itself, the pressure swing adsorption method, which is cheaper than the cryogenic method, costs 0.3 yuan / m3 to produce nitrogen; while the cost of producing nitrogen by vaporizing liquid nitrogen is 1.3-1.6 yuan / m3, which is less economical.

[0027] Example 2 See Figure 2This embodiment is an optimization of Embodiment 1, adding the following features: the monitoring device consists of three sets of temperature-measuring thermocouples 4. The temperature-measuring thermocouples 4 are installed on the top of the regenerative regulating furnace 1, arranged along the central axis, at positions 200mm from the inlet, center, and 200mm from the outlet of the regenerative regulating furnace 1, respectively; the air supply equipment uses a centrifugal fan 14 with specifications of 2100 m³ / h, total pressure of 12.74 kPa, and motor power of 15 kW, and the cooling gas is changed to air. The controller 6 presets the furnace temperature setpoint and deviation setpoint. The furnace temperature setpoint range is 640℃~660℃, and the deviation setpoint is 30℃. After the fixed anode furnace starts the reduction operation, the manual regulating valve 7 of the air supply pipeline 8 and the regulating valve of the spray gun 3 are opened. The controller 6 receives temperature values ​​detected by three sets of thermocouples 4 and calculates the average temperature value. It then compares the average temperature value with the furnace temperature setpoint. If the average temperature value is higher than the setpoint, the controller 6 interlocks and opens the pneumatic switch valve 5 and pneumatic regulating valve 13 of the air supply line 8, supplying cooling air to the spray gun 3. If the deviation between the average temperature value and the setpoint is greater than the deviation setpoint, the controller 6 uses a PID algorithm to pneumatically adjust the opening of the regulating valve, changing the input air flow until the deviation is less than the deviation setpoint. When the average temperature value is lower than the setpoint, the controller 6 interlocks and closes the pneumatic switch valve 5 and pneumatic regulating valve 13 of the air supply line 8, stopping the supply of air to the spray gun 3. The cooling air, after passing through the spray gun 3 and the swirl vane 32 at the outlet, is injected into the regenerative regulating furnace 1 in a swirling manner, ensuring sufficient contact with the flue gas to reduce its temperature. The manual regulating valve 7 is fully open. By changing the opening degree of the manual switch valve at the inlet of spray gun 3, the flow rate of the cooling medium in spray gun 3 is adjusted. Typically, the manual switch valve on the inlet side of spray gun 3 in regenerative regulating furnace 1 is fully open, while the opening degree of the manual switch valve on the outlet side of spray gun 3 is 30%~100%. During the reduction operation of the fixed anode furnace, the flue gas regulating gates 15 at the inlet and outlet of regenerative regulating furnace 1 are maintained at an opening degree of over 40%. Practical application of this embodiment shows that the regenerative regulating furnace 1 did not explode, meeting safety production requirements. Air is supplied by a separately configured centrifugal fan 14, which has a small motor power and operates near full load, resulting in low power consumption. Although the air pressure is low, it meets process requirements. The large opening degree of the flue gas regulating gates 15 at the inlet and outlet of regenerative regulating furnace 1 reduces safety risks. During the reduction operation of the fixed anode furnace, the bypass flue gas flow rate entering the regenerative regulating furnace 1 increases, utilizing more waste heat from the flue gas; the main flue gas flow rate decreases, resulting in a greater temperature drop and a greater reduction in the operating cost of the flue gas cooling equipment. The application of this embodiment shows that when the cooling medium is air with a pressure of 2KPa to 12KPa, using a centrifugal fan 14 as the air supply device yields more significant technical and economic benefits, making it the preferred solution. See comparative examples. Figure 4This comparative example prevents explosions by adding inert gas into the regenerative regulating furnace 1 to alter the explosion limits of explosive substances. For CO and CH4, commonly used explosion-proof inert gases in industry are CO2 and N2. This comparative example uses a nitrogen storage tank 10 to supply nitrogen, with a total nitrogen input of 100 m³ / h to 500 m³ / h for the spray gun 3. Practical application shows that the flue gas regulating gates 15 at the inlet and outlet of the regenerative regulating furnace 1 are often simultaneously closed or have an opening of less than 5%, without any explosions occurring. However, the controllability of this scheme is poor because the flue gas composition of the regenerative regulating furnace 1 cannot be monitored in real time. A large flow of nitrogen can only be continuously introduced during the reduction phase of the fixed anode furnace to reduce the risk of explosion when the regenerative regulating furnace 1 forms a relatively enclosed space. This results in nitrogen consumption per furnace cycle being 160% of that in Example 1, and the same nitrogen supply problem exists as in Example 1. If there is no oxygen production plant nearby to provide pipeline nitrogen, it is uneconomical.

Claims

1. A safety protection system for a regenerative regulating furnace, characterized in that: The system includes a monitoring device, an air supply device, and a controller. The monitoring device is used to detect the temperature inside the regenerative thermal regulating furnace. The air supply device includes an air supply pipeline, a spray gun, and air supply equipment. The spray gun is installed on the top or side of the regenerative thermal regulating furnace to spray cooling gas into the furnace. One end of the air supply pipeline is connected to the spray gun, and the other end is connected to the air supply equipment. A regulating valve group is provided on the air supply pipeline. The regulating valve group and the monitoring device are respectively connected to the controller for signal connection. The controller receives the furnace temperature detection value from the monitoring device and compares it with the set temperature. It automatically controls the opening of the regulating valve group to input cooling gas into the furnace for cooling.

2. The safety protection system for a regenerative regulating furnace according to claim 1, characterized in that: The cooling gas is either compressed air or nitrogen.

3. The safety protection system for a regenerative regulating furnace according to claim 1, characterized in that: The air supply pipeline is equipped with a pressure regulating device, which is used to adjust the gas pressure entering the spray gun.

4. The safety protection system for a thermal regenerative regulating furnace according to claim 1, characterized in that: The spray gun includes a circular tube, and one end of the circular tube inserted into the furnace is equipped with a swirl vane. The swirl vane is used to make the cooling gas enter the regenerative regulating furnace in a swirling form.

5. The safety protection system for a thermal regenerative regulating furnace according to claim 1, characterized in that: The spray gun is equipped with a spray gun holder, which is fixedly connected to the heat storage and regulating furnace. The spray gun holder has an installation hole, through which the spray gun is inserted into the heat storage and regulating furnace.

6. The safety protection system for a regenerative regulating furnace according to claim 1, characterized in that: The regulating valve group includes a pneumatic switch valve, a pneumatic regulating valve, and a flow meter; the monitoring device uses a temperature measuring thermocouple.

7. A safety protection method for a thermal regenerative regulating furnace, characterized in that: The regenerative regulating furnace safety protection system according to any one of claims 1-6 specifically includes the following steps: after the anode furnace starts the reduction operation, the air supply pipeline is opened to prepare to input cooling gas into the regenerative regulating furnace; the controller receives the temperature value detected by the monitoring device and compares it with the furnace temperature setpoint: if the temperature value is higher than the furnace temperature setpoint, the controller interlocks and opens the regulating valve group of the air supply pipeline to input cooling gas into the spray gun; when the temperature value is lower than the furnace temperature setpoint, the controller interlocks and closes the regulating valve group of the air supply pipeline to stop inputting cooling gas into the spray gun.

8. A safety protection method for a regenerative regulating furnace according to claim 7, characterized in that: The monitoring device uses multiple sets to detect the temperature at different locations. The controller calculates the average value of the temperature values ​​monitored by the multiple sets of monitoring devices and compares it with the furnace temperature setpoint. Based on the magnitude of the deviation, the controller controls the opening of the regulating valve group to adjust the flow rate of cooling gas in the air supply pipeline, thereby adjusting the cooling rate.

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