Integrated gas-solid separation waste acid regeneration cracking furnace and control system thereof

Abstract

The invention relates to the technical field of chemical equipment, and particularly discloses an integrated gas-solid separation waste acid regeneration cracking furnace, comprising: a furnace body, a combustion chamber is arranged in the furnace body, a plurality of first baffle plates and second baffle plates are arranged in the combustion chamber, and the first baffle plates and the second baffle plates are alternately arranged at equal intervals along the axis of the furnace body to form baffling channels; the gas-solid separator is connected to the outlet end of the furnace body and comprises an outer pipe and an inner pipe which are coaxially arranged, and a flow guide assembly is arranged in the gas-solid separator; the induced draft fan is arranged at one end, far away from the furnace body, of the gas-solid separator; and the control system is used for detecting the pressure in the furnace body through a pressure transmitter, adjusting the rotating speed of the induced draft fan by adopting a PID control algorithm, and maintaining the micro-negative pressure state in the furnace body. Accurate control of pressure in the cracking furnace and efficient gas-solid separation are achieved, the waste acid regeneration efficiency and the equipment operation stability are improved, and environmental pollution and energy consumption are reduced.

Description

Technical Field

[0001] This application relates to the technical field of chemical equipment, and in particular to an integrated gas-solid separation waste acid regeneration pyrolysis furnace and its control system. Background Technology

[0002] Waste sulfuric acid pyrolysis is a crucial process for treating waste sulfuric acid and recovering sulfuric acid. The operational stability and efficiency of its core equipment, the pyrolysis furnace, are paramount. During pyrolysis, a large amount of high-temperature flue gas carrying dust, incompletely decomposed carbon particles, and other solid particles is generated. If these particles are not effectively treated, they can clog subsequent pipelines and equipment, accelerate equipment wear, affect product quality, and even lead to unplanned production shutdowns.

[0003] In existing technologies, gas-solid separation devices such as cyclone separators are typically installed after the pyrolysis furnace. However, such traditional pyrolysis furnaces have the following problems: the ash removal operation of the separator relies heavily on manual experience or timed control, and cannot respond according to the actual ash accumulation. This can easily lead to untimely ash removal, resulting in increased system resistance, or excessive ash removal, leading to energy waste and equipment wear. The stability of the furnace pressure is crucial for safe production and pyrolysis efficiency. Traditional control methods cannot accurately maintain the required slight negative pressure in the furnace. Pressure fluctuations can easily lead to flue gas leakage or air ingress, posing safety risks and affecting combustion efficiency. Summary of the Invention

[0004] To address the issue of existing separators relying on manual labor, this application provides an integrated gas-solid separation waste acid regeneration pyrolysis furnace and its control system.

[0005] On the one hand, the integrated gas-solid separation waste acid regeneration pyrolysis furnace provided in this application adopts the following technical solution: An integrated gas-solid separation waste acid regeneration pyrolysis furnace includes: The furnace body has an inlet end and an outlet end. A combustion chamber is opened inside the furnace body. Multiple first baffles and multiple second baffles are installed in the combustion chamber. The first baffles and second baffles are arranged at equal intervals along the axis of the furnace body. The first baffles and second baffles are arranged alternately to form a baffle channel in the combustion chamber. A gas-solid separator is connected to the outlet end of the furnace body and is used to separate the gas and solids in the flue gas after combustion in the furnace body. An induced draft fan is located at the end of the gas-solid separator furthest from the furnace body. The induced draft fan is used to draw furnace gas to create negative pressure inside the furnace body. A pressure transmitter is installed at the outlet end of the furnace body. The pressure transmitter is used to detect the pressure inside the furnace body and transmit it to the control unit. The speed of the induced draft fan is controlled by an algorithm to achieve pressure control inside the furnace body.

[0006] By adopting the above technical solution, a pressure control system based on PID algorithm is integrated. The system monitors the furnace pressure in real time through a pressure transmitter and automatically and accurately adjusts the induced draft fan speed. This eliminates the reliance on the operator's experience and avoids the risk of human error. The system can dynamically stabilize the furnace pressure within the optimal micro-negative pressure range, effectively preventing the leakage of toxic and harmful flue gas, ensuring safe production and personnel health, and ensuring the continuous stability of the pyrolysis reaction conditions. In some embodiments, the distance between adjacent first and second baffles is 30-45 mm. In some embodiments, the gas-solid separator includes an outer tube and an inner tube, the inner tube is disposed inside the outer tube and is coaxially arranged with the outer tube, a separation cavity is provided between the outer tube and the inner tube, a solid outlet is provided at the bottom of the outer tube and is connected to the separation cavity, and a gas outlet is provided inside the inner tube.

[0007] In some embodiments, a flow guiding assembly is provided inside the gas-solid separator. The flow guiding assembly includes multiple first flow guiding plates and multiple second flow guiding plates. The first flow guiding plates are located on the side near the furnace outlet end, and the second flow guiding plates are located on the side away from the furnace outlet end. The multiple first flow guiding plates are distributed at equal intervals along the inner peripheral wall of the outer tube, and the multiple second flow guiding plates are distributed at equal intervals along the outer peripheral wall of the inner tube.

[0008] In some embodiments, the number of first guide vanes is 10 to 12, each first guide vane is spirally arranged, the pitch of each first guide vane is 280 to 340 mm, the height is 30 to 40 mm, and the thickness is 1.5 to 3 mm; the number of second guide vanes is 10 to 12, each second guide vane is spirally arranged, the pitch of each second guide vane is 120 to 180 mm, the height is 10 to 20 mm, and the thickness is 1.5 to 3 mm.

[0009] On the other hand, this application also provides an integrated gas-solid separation waste acid regeneration pyrolysis furnace control system for controlling the integrated gas-solid separation waste acid regeneration pyrolysis furnace as described above, comprising the following steps: S1. Real-time pressure measurement values ​​inside the pyrolysis furnace are obtained through a pressure detection device; S2. Calculate the deviation between the measured pressure value and the preset pressure setting value; S3. A PID control algorithm is used to calculate the control signal based on the deviation; S4. Adjust the speed of the induced draft fan according to the control signal to maintain a slight negative pressure state inside the pyrolysis furnace.

[0010] In some implementations, in step S1, the pressure transmitter converts the detected pressure signal into a 4~20mA current signal and processes it using a first-order hysteresis filter, wherein the filter coefficient α is 0.4~0.6.

[0011] In some implementations, in step S2, to maintain a slight negative pressure inside the pyrolysis furnace, the preset pressure range is -30 to -20 Pa. In each control cycle, the difference between the current measured pressure value and the set value is calculated using the following formula: Where Pv is the current pressure measurement value, Sv is the pressure set value, and e(t) is the difference between the two; if e(t)>0, it means that the pressure inside the furnace is higher than the set value, that is, the negative pressure is insufficient, and the induced draft fan force needs to be increased; otherwise, the induced draft fan force should be reduced.

[0012] In some implementations, step S3 uses a discretized positional PID algorithm: Where Output(t) is the calculated output value of the PID controller at the current moment; Kp is the proportional gain, which determines the reaction intensity of the current deviation; Ki is the integral gain, Ki=Kp(T / Ti), where T is the control period, ranging from 100 to 200 ms; Ti is the integral time constant; Kd is the derivative gain, Kd=Kp(Td / T), where Td is the derivative time constant; Σ[e(t)T] is the sum of deviations at all times. The three parameters Kp, Ki, and Kd need to be determined using the critical proportional gain method.

[0013] In some implementations, in step S4, the calculated Output(t) is output-limited to ensure it remains within the safe operating range of the actuator, typically between 50% and 80%. The limited output value is then converted into a standard 4-20mA analog signal, Analog_Output, and sent to the induced draft fan. This signal is linearly mapped to the output frequency, and the power frequency supplied to the induced draft fan motor is adjusted based on the frequency to control its rotational speed. When the induced draft fan speed changes, the furnace pressure changes accordingly. The pressure transmitter immediately detects this change and feeds back the new Pv value, forming a closed-loop negative feedback.

[0014] Compared with the prior art, this application includes at least one of the following beneficial technical effects: 1. This application combines the furnace body with the gas-solid separator to construct a highly integrated system, eliminating the need for independent separation equipment, connecting pipelines and supporting civil engineering, which significantly reduces equipment investment costs, installation costs and subsequent land area and operation and maintenance costs; 2. By monitoring the pressure inside the combustion chamber in real time through a pressure transmitter and automatically and accurately adjusting the speed of the induced draft fan, the system eliminates the reliance on the operator's experience and avoids the risk of human error. The system can dynamically stabilize the furnace pressure within the optimal micro-negative pressure range, effectively preventing the leakage of toxic and harmful flue gas, ensuring safe production and personnel health, and ensuring the continuous stability of the pyrolysis reaction conditions. 3. The gas-solid separator, through the combination of the first and second guide plates, and by setting a specific number, pitch and size of guide plates, forces the flue gas to swirl and guide in two stages, thereby generating a strong and stable centrifugal force field, which can efficiently capture and separate solid impurities such as dust and incompletely decomposed carbon particles carried in the pyrolysis flue gas. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the integrated gas-solid separation waste acid regeneration pyrolysis furnace in the embodiments of this application.

[0016] Figure 2 This is a schematic diagram of the gas-solid separator in the embodiments of this application.

[0017] Figure 3 This is a schematic diagram of the gas-solid separator in the embodiments of this application.

[0018] In the picture: 1. Furnace body; 11. Combustion chamber; 12. Inlet end; 13. Outlet end; 14. First baffle; 15. Second baffle; 16. Burner hole; 17. Waste acid spray gun hole; 18. Flame monitor; 19. Sight glass; 20. Manhole; 201. Explosion-proof diaphragm mounting port; 5. Gas-solid separator; 51. Outer pipe; 52. Inner pipe; 53. Separation chamber; 54. Solid outlet; 55. Gas outlet; 56. First guide plate; 57. Second guide plate; 58. Pressure transmitter; 6. Exhaust fan. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0021] Reference Figure 1This application provides an integrated gas-solid separation waste acid regeneration pyrolysis furnace and its control system, including a furnace body 1, a gas-solid separator 5, and an induced draft fan 6. The furnace body 1 has an inlet end 12 and an outlet end 13. The gas-solid separator 5 is located at the outlet end 13 of the furnace body 1 and is sealed to the furnace body 1, which can be connected via a flange. A combustion chamber 11 is formed inside the furnace body 1, and multiple first baffles 14 and multiple second baffles 15 are arranged inside the combustion chamber 11. The first baffles 14 and the second baffles 15 are arranged at equal intervals along the axis of the furnace body 1. The first baffles 14 and the second baffles 15 are arranged alternately to form a baffle channel in the combustion chamber 11. The distance between adjacent first baffles 14 and second baffles 15 is 30~45mm. Through this design, the waste acid can form a baffle channel in the combustion chamber 11, prolonging the residence time of the waste acid in the high-temperature zone and improving the pyrolysis efficiency of the waste acid.

[0022] Waste acid spray gun holes 17 and burner holes 16 are provided on the end face of the inlet end 12 of the furnace body 1. A flame monitor 18, a sight glass 19, a manhole 20 and an explosion-proof diaphragm mounting port 201 are provided on the side wall of the furnace body 1. The waste acid spray gun holes 17 are evenly distributed in a circle around the burner holes 16. There are 4 to 6 waste acid spray gun holes 17, and the distance between the center of each waste acid spray gun hole 17 and the center of the burner hole 16 is 40 to 55 mm. The waste acid spray gun holes 17 spray along the axial direction of the furnace body 1.

[0023] Reference Figures 1 to 3 The gas-solid separator 5 is connected to the outlet end 13 of the furnace body 1 and is used to separate the gas and solid components of the flue gas after combustion in the furnace body 1. Figure 2 As shown, the gas-solid separator 5 includes an outer tube 51 and an inner tube 52. The inner tube 52 is disposed inside the outer tube 51 and is coaxially arranged with the outer tube 51. A separation chamber 53 is provided between the outer tube 51 and the inner tube 52. A solid outlet 54 is opened at the bottom of the outer tube 51, and the solid outlet 54 is connected to the separation chamber 53. A gas outlet 55 is opened in the inner tube 52. A flow guiding assembly is provided inside the gas-solid separator 5, which includes multiple first flow guiding plates 56 and multiple second flow guiding plates 57. The first flow guiding plates 56 are disposed on the side near the outlet end 13 of the furnace body 1, and the second flow guiding plates 57 are disposed on the side away from the outlet end 13 of the furnace body 1. The multiple first flow guiding plates 56 are distributed at equal intervals along the inner peripheral wall of the outer tube 51, and the multiple second flow guiding plates 57 are distributed at equal intervals along the outer peripheral wall of the inner tube 52. Specifically, the first flow guiding plates 56 and the second flow guiding plates 57 are fixedly connected to the inner wall of the furnace body 1, which can be by welding.

[0024] By combining the gas-solid separator 5 with the furnace body 1, a highly integrated system is constructed, eliminating the need for independent separation equipment, connecting pipelines, and supporting civil engineering, thereby reducing the initial investment cost, equipment installation cost, and subsequent land area and operation and maintenance costs.

[0025] Specifically, there are 10 to 12 first guide plates 56, each spirally arranged; the pitch of each first guide plate 56 is 280 to 340 mm, the height is 30 to 40 mm, and the thickness is 1.5 to 3 mm. There are also 10 to 12 second guide plates 57, each spirally arranged; the pitch of each second guide plate 57 is 120 to 180 mm, the height is 10 to 20 mm, and the thickness is 1.5 to 3 mm. The spiral arrangement of the first guide plates 56 and the second guide plates 57 allows the gas-solid mixture to rotate within the gas-solid separator 5, using centrifugal force to separate solid particles and improve gas-solid separation efficiency.

[0026] An induced draft fan 6 is located at the end of the gas-solid separator 5 furthest from the furnace body 1. The induced draft fan 6 draws in furnace gas to create a negative pressure within the furnace body 1. A pressure transmitter 58 is installed at the outlet end 13 of the furnace body 1. The pressure transmitter 58 detects the pressure within the furnace body 1 and transmits it to the control unit. An algorithm controls the rotation speed of the induced draft fan 6 to achieve pressure control within the furnace body 1. It is easy to understand that the pressure transmitter 58 can be connected to the furnace body 1 via a flange or a pressure-sensing pipe. The connection method between the pressure transmitter 58 and the furnace body 1 is existing technology and will not be elaborated further. By installing the pressure transmitter 58, the pressure status within the furnace body 1 can be monitored in real time, and the negative pressure within the furnace body 1 can be maintained by adjusting the rotation speed of the induced draft fan 6, preventing the leakage of harmful gases and ensuring that the pyrolysis process takes place under optimal pressure conditions, thereby improving pyrolysis efficiency and safety.

[0027] During operation, waste acid enters the inlet 12 of the furnace body 1 and undergoes a pyrolysis reaction upon contact with high temperature within the combustion chamber 11. The gas-solid mixture produced by pyrolysis flows through the baffle channel formed by the first baffle 14 and the second baffle 15, extending the residence time in the high-temperature zone and improving pyrolysis efficiency. The gas-solid mixture then enters the gas-solid separator 5, where it forms a rotating flow under the action of the first guide plate 56 and the second guide plate 57. Solid particles are separated under centrifugal force and discharged through the solid outlet 54, while the gas is discharged through the gas outlet 55 of the inner pipe 52. Throughout the process, the induced draft fan 6 operates continuously, creating a negative pressure within the furnace body 1. The pressure transmitter 58 monitors the pressure status within the furnace body 1 in real time and adjusts the speed of the induced draft fan 6 through the control unit to ensure the system operates under optimal conditions.

[0028] This application also provides an integrated gas-solid separation waste acid regeneration pyrolysis furnace control system. The system includes main components such as furnace body 1, gas-solid separator 5, and induced draft fan 6. The implementation process of the integrated gas-solid separation waste acid regeneration pyrolysis furnace control system is mainly as follows: S1: Pressure signal acquisition and processing: The pressure transmitter 58 acquires real-time pressure measurements inside the pyrolysis furnace and converts the detected pressure signal into a 4-20mA current signal. To eliminate signal fluctuations, the system employs a first-order hysteresis filter to process the signal, with the filter coefficient α set between 0.4 and 0.6. In practical applications, the α value can be 0.45, 0.5, or 0.55; in this embodiment, the preferred α value is 0.5. The filtered signal is more stable and accurately reflects the actual pressure state inside the furnace.

[0029] S2: Pressure Difference Calculation: The system calculates the deviation between the measured pressure value and the preset pressure setting value. To maintain a slightly negative pressure state inside the pyrolysis furnace, the preset pressure range is -30 to -20 Pa. In each control cycle, the system calculates the difference e(t) between the current measured pressure value and the set value, using the following formula: Where Pv is the current pressure measurement value, Sv is the pressure setpoint, and e(t) is the difference between the two; if e(t)>0, it means that the pressure inside the furnace is higher than the setpoint, that is, the negative pressure is insufficient, and the induced draft fan force needs to be increased; if e(t)<0, it means that the negative pressure inside the furnace is too large, and the induced draft fan force needs to be reduced. This difference calculation method ensures that the system can make accurate adjustments according to the actual pressure deviation.

[0030] S3: PID control algorithm calculation: The system employs a PID control algorithm to calculate the control signal based on the pressure deviation. Specifically, it uses a discretized positional PID algorithm, with the calculation formula as follows: in: K p The proportional gain determines the intensity of the response to the current deviation; K i For integral gain, K i =K p (T / T i T is the control period, which is 100~200ms, preferably 150ms; T i The integral time constant; K d For differential gain, K d =K p (T d / T), T d The differential time constant; Σ[e(t)T] is the sum of the deviations over all time points; e(t)-e(t-1) is the difference between the current deviation and the deviation at the previous time step.

[0031] K p K i K d The three parameters were determined using the critical proportionality method. First, K... i and K d Set K to 0 and gradually increase it. p Record K until the system exhibits constant amplitude oscillation. p The value is K u The oscillation period is T. u Then, the final PID parameters are calculated based on the empirical formula: K p =0.6K u T i =0.5T u T d =0.125T u .

[0032] S4: Control of Exhaust Fan 6: Adjust the induced draft fan speed according to the control signal to maintain a slight negative pressure state inside the pyrolysis furnace. The specific steps are as follows: (1) Limit the calculated Output(t) to ensure that it is within the safe operating range of the actuator, with a limit range of 50-80%; (2) Convert the limited output value into a standard 4-20mA analog signal Analog_Output; (3) Send the Analog_Output signal to the induced draft fan 6 and linearly map it to the output frequency; (4) Adjust the power frequency supplied to the induced draft fan motor according to the frequency to control its speed.

[0033] When the speed of the induced draft fan 6 changes, the furnace pressure changes accordingly. The pressure transmitter 58 immediately detects this new change and feeds back the new pressure measurement value to the control system, forming a closed-loop negative feedback control. The entire process can be described as follows: when the furnace pressure increases, the control system increases the output frequency, the speed of the induced draft fan 6 increases, the draft force increases, and the furnace pressure decreases; conversely, when the negative pressure inside the furnace is too high, the control system decreases the output frequency, the speed of the induced draft fan 6 decreases, the draft force weakens, and the furnace pressure increases.

[0034] This precise control based on the PID algorithm, combined with the filtering of the pressure signal and the closed-loop regulation of the induced draft fan speed, can effectively maintain a slightly negative pressure state inside the pyrolysis furnace, prevent the leakage of harmful gases, and avoid energy waste and equipment damage caused by excessive negative pressure, thus ensuring the safe, efficient and stable operation of the entire pyrolysis furnace system.

[0035] The implementation principle of this application embodiment is as follows: Waste acid and fuel enter the furnace body 1 through the inlet end 12 and undergo a high-temperature pyrolysis reaction in the combustion chamber 11 to generate a mixture of high-temperature flue gas and solid particles. The flue gas is guided by the baffle channel formed by the alternating arrangement of the first baffle 14 and the second baffle 15 in the furnace body 1, and flows in a tortuous path, which effectively prolongs the residence time in the high-temperature zone and promotes the full pyrolysis of waste acid.

[0036] Subsequently, the flue gas enters the gas-solid separator 5, which is connected to the outlet 13 of the furnace body 1. In the gas-solid separator 5, the flue gas first passes through the first guide plate 56 and forms a swirling flow along the inner wall of the outer tube 51; then it enters the annular separation chamber 53 composed of the inner and outer tubes 51, where the swirling flow is further enhanced by the second guide plate 57, causing the gas-solid mixture to generate a strong centrifugal force. Under the action of centrifugal force, solid particles are thrown towards the inner wall of the outer tube 51, settle along the wall surface, and are discharged from the bottom solid outlet 54; while the purified gas enters the inner tube 52 and is discharged through the gas outlet 55, completing the gas-solid separation process.

[0037] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An integrated gas-solid separation spent acid regeneration cracking furnace, characterized in that, It comprises: furnace body (1), with the inlet end (12) and the outlet end (13), the combustion chamber (11) is opened in the furnace body (1), the first baffle (14) and the second baffle (15) are arranged in the combustion chamber (11), the first baffle (14) and the second baffle (15) are equidistantly arranged along the axis of the furnace body (1), the first baffle (14) and the second baffle (15) are alternately arranged, to form a zigzag channel in the combustion chamber (11); Gas-solid separator (5) is connected to the outlet end (13) of the furnace body (1), for gas-solid separation of flue gas after combustion in the furnace body (1); Induced draft fan (6) is arranged at the end of the gas-solid separator (5) away from the furnace body (1), the induced draft fan (6) is used for extracting furnace gas to form negative pressure in the furnace body (1), the outlet end (13) of the furnace body (1) is provided with a pressure transmitter (58), the pressure transmitter (58) is used for detecting the pressure in the furnace body (1) and transmitting to the control unit, the rotating speed of the induced draft fan (6) is controlled by algorithm to realize the pressure control in the furnace body (1).

2. The integrated gas-solids separation spent acid regeneration cracking furnace of claim 1, wherein: The distance between the adjacent first baffle (14) and the second baffle (15) is 30~45mm.

3. The integrated gas-solids separation spent acid regeneration cracking furnace of claim 1, wherein: The gas-solid separator (5) comprises an outer tube (51) and an inner tube (52), the inner tube (52) is arranged in the outer tube (51), and is coaxially arranged with the outer tube (51), the outer tube (51) and the inner tube (52) have a separation chamber (53), the outer tube (51) is provided with a solid outlet (54) at the bottom, the solid outlet (54) is communicated with the separation chamber (53), and the inner tube (52) is provided with a gas outlet (55).

4. The integrated gas-solids separation spent acid regeneration cracking furnace of claim 3, wherein: The gas-solid separator (5) is provided with a flow guide assembly, the flow guide assembly comprises a plurality of first flow guide plates (56) and a plurality of second flow guide plates (57), the first flow guide plates (56) are arranged on one side close to the outlet end (13) of the furnace body (1), the second flow guide plates (57) are arranged on one side away from the outlet end (13) of the furnace body (1), a plurality of the first flow guide plates (56) are equidistantly distributed along the inner circumferential wall of the outer tube (51), and a plurality of the second flow guide plates (57) are equidistantly distributed along the outer circumferential wall of the inner tube (52).

5. The integrated gas-solids separation spent acid regeneration cracking furnace of claim 4, wherein: The number of the first flow guide plates (56) is 10~12, each first flow guide plate (56) is spirally arranged, the pitch of each first flow guide plate (56) is 280~340mm, the height is 30~40mm, and the thickness is 1.5~3mm; the number of each second flow guide plate (57) is 10~12, each second flow guide plate (57) is spirally arranged, the pitch of the second flow guide plate (57) is 120~180mm, the height is 10~20mm, and the thickness is 1.5~3mm.

6. An integrated gas-solids separation spent acid regeneration cracking furnace control system for controlling the integrated gas-solids separation spent acid regeneration cracking furnace of any one of claims 1 to 5, characterized in that, It comprises the following steps: S1. Real-time acquisition of pressure measurement value in the cracking furnace by pressure detection device; S2. Calculate the deviation of the pressure measurement value and the preset pressure set value; S3. Adopting PID control algorithm, calculating control signal according to the deviation; S4. Adjusting the speed of the induced draft fan (6) according to the control signal to maintain the micro-negative pressure state in the cracking furnace.

7. The integrated gas-solids separation spent acid regeneration cracking furnace control system of claim 6, wherein: In the step S1, the pressure transmitter (58) converts the detected pressure signal into a 4-20 mA current signal, and uses a first-order lag filter method for processing, wherein the filter coefficient a is 0.4-0.

6.

8. The integrated gas-solids separation spent acid regeneration cracking furnace control system of claim 6, wherein: In the step S2, in order to maintain the micro-negative pressure in the cracking furnace, the preset pressure value range is-30--20 Pa, and in each control cycle, the difference between the current pressure measurement value and the set value is calculated, and the formula is as follows:

9. wherein, P v S is the current pressure measurement value v e(t) is the difference between the two; if e(t) > 0, it means that the pressure inside the furnace is higher than the set value, i.e. the underpressure is insufficient, and the induced draft fan (6) must be increased, vice versa.

10. The integrated gas-solid separation waste acid regeneration cracking furnace control system according to claim 6, characterized in that: In the step S3, a discrete position PID algorithm is used:

11. wherein, Output(t) is the calculated output value of the PID controller at the current time; K p is the proportional gain, which determines the reaction strength of the current deviation; K i is the integral gain, K i =K p (T / T i ), T is the control period, which is 100-200 ms; T i is the integral time constant; K d is the derivative gain, K d =K p (T d / T), T d is the derivative time constant; Σ[e(t)T] is the accumulation of all time deviations; K p , K i , K d The three parameters need to be determined by the critical proportionality method.

12. The integrated gas-solid separation waste acid regeneration cracking furnace control system according to claim 6, characterized in that: The step S4, the calculated Output (t) is output amplitude limiting, to ensure that it is within the safe working range of the actuator, limit range is 50~80%, the output value after limiting the conversion to standard 4-20mA analog signal Analog_Output, will be sent to the induced draft fan (6), linear mapping as output frequency Frequency, according to Frequency adjustment output to the motor of the induced draft fan (6) power frequency, so as to control its speed; the induced draft fan (6) speed changes, the furnace pressure changes, the pressure transmitter (58) detects the new change, and the new P v value feedback forms a closed loop negative feedback.

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