Self-sustaining operation intelligent control system for prying type super-low concentration gas regenerative oxidation

Abstract

The application discloses a prying-mounted intelligent regulation and control system for self-sustained operation of regenerative oxidation of ultra-low concentration gas, comprising a three-chamber regenerative oxidation reactor, a primary air blower, a secondary air blower, a regenerative oxidation combustion chamber, a back pressure turbine, a waste heat recovery device, a steam heat exchanger, an air induction blower, a dust collector, a pretreatment device, a buffer tank, a flow meter, a generator and a prying-mounted base; the HMI host computer monitoring system and the PLC control system are used for collecting CH4, O2, CO, flow, temperature, pressure, pressure difference, steam parameters, fan rotating speed and the state of the generator in real time, and automatically adjusting the gas valve, the air valve, the fan rotating speed, the switching valve group action and the operation state of the regenerative device, so that stable self-sustained operation of the system is realized.

Description

Technical Field

[0001] This invention belongs to the field of ultra-low concentration gas resource utilization and intelligent control technology, specifically involving a skid-mounted ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system, which is suitable for the safe, efficient, and continuous treatment and comprehensive energy utilization of ultra-low concentration exhaust gas in coal mines and other scenarios. Background Technology

[0002] Ultra-low concentration methane is an important byproduct of coal mining and ventilation, characterized by low concentration, large fluctuations, low calorific value, high flammability and explosiveness, and high difficulty in control. Existing exhaust methane treatment methods mostly employ direct emission, simple combustion, or single-stage heat utilization, which generally suffer from low energy utilization efficiency, high system start-up energy consumption, poor operational stability, single level of waste heat recovery, and difficulty in long-term stable self-sustaining operation.

[0003] Regenerative thermal oxidation (RTO) technology utilizes a heat storage medium to store and release reaction heat, thereby achieving stable oxidation treatment of ultra-low concentration methane, offering advantages such as high destruction efficiency and stable operating temperature. However, existing RTO systems still suffer from the following shortcomings in actual operation: First, the utilization of waste heat from exhaust gas is relatively singular, making it difficult to achieve cascade recovery and comprehensive utilization; second, there is a lack of intake gas reheating measures, resulting in high energy consumption during system startup and low-load phases; third, the equipment is bulky, occupies a large area, and has low system integration, significantly lagging behind skid-mounted modular designs; fourth, the level of intelligence is insufficient, lacking unified online monitoring, fault diagnosis, and adaptive control capabilities for key operating parameters such as methane concentration, oxygen concentration, flow rate, temperature, pressure, differential pressure, and steam parameters, leading to weak system self-sufficiency and poor operational stability. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a skid-mounted, ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system. This system combines intake preheating, regenerative oxidation, exhaust gas waste heat recovery, steam power generation, and heating utilization, supplemented by PLC intelligent control and safety interlocking mechanisms, to improve the system's thermal efficiency, operational stability, and comprehensive energy utilization level.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A skid-mounted, ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system includes:

[0007] The three-chamber regenerative oxidation reactor is used for regenerative oxidation of ultra-low concentration methane. It is equipped with regenerative beds A, B, and C. The airflow is periodically reversed between the three chambers to achieve alternating cycles of heat storage and release in the regenerative body, so as to maintain a stable reaction temperature.

[0008] Primary air fans are used to provide air distribution for the system;

[0009] Secondary air fans are used to provide air distribution to the system and work in conjunction with primary air fans to regulate the total air volume and air distribution ratio.

[0010] The regenerative oxidation combustion chamber is located inside the three-chamber regenerative oxidation reactor to provide reaction space for the gas oxidation reaction;

[0011] Back-pressure steam turbines are used to generate electricity and provide heat using steam.

[0012] Waste heat recovery unit is used to recover waste heat from the high-temperature tail gas after the reaction.

[0013] Steam heat exchangers are used to convert recovered heat into steam;

[0014] Exhaust fan is used to maintain negative pressure in the system and transport exhaust gas;

[0015] Dust collectors are used to purify exhaust gases.

[0016] Pretreatment unit, used for dust removal, dehydration and purification of methane gas;

[0017] Buffer tanks are used to stabilize and buffer ultra-low concentration methane at wellheads in the field.

[0018] A flow meter is used to detect the flow rate of gas entering the system;

[0019] A regenerator, located on the air inlet side, is used to preheat the air before it enters the reactor;

[0020] A generator is used to output electrical energy;

[0021] The skid-mounted base is used to support the various components of the system, enabling overall skid-mounted integration.

[0022] Preferably, the system also includes: a switching valve group for controlling the periodic reversal and airflow distribution of the three-chamber regenerative thermal oxidation reactor; a V1 valve located at the inlet side of the three-chamber regenerative thermal oxidation reactor for regulating the gas flow rate; V2 / V3 / V4 valves, which are respectively the regenerator outlet regulating valve and the primary / secondary fan outlet regulating valve, for regulating the air and preheated air flow rates; a V5 valve located at the buffer tank outlet side for controlling or cutting off the gas flow rate into the pretreatment unit; and an HMI upper computer monitoring system and a PLC control system for data acquisition, operating condition identification, closed-loop regulation, and interlock protection.

[0023] As a preferred method, after the ultra-low concentration methane enters the system from the wellhead, it first enters the buffer tank for pressure stabilization and buffering, and then enters the pretreatment device for dust removal, dehydration and purification under the control of valve V5. The pretreated methane is metered by a flow meter and enters the methane intake channel of the three-chamber regenerative thermal oxidation reactor under the control of valve V1. The air is provided by the primary air fan and the secondary air fan, and a portion of the air can be preheated by the regenerator before entering the air intake channel of the three-chamber regenerative thermal oxidation reactor.

[0024] As a preferred embodiment, after the gas and preheated air enter the three-chamber regenerative oxidation reactor, the oxidation reaction is completed in the regenerative oxidation combustion chamber. The three-chamber regenerative oxidation reactor is equipped with regenerative beds A, B, and C. During the reaction, the airflow is periodically reversed by switching valve groups, so that the high-temperature flue gas can exchange heat with the regenerative body.

[0025] Preferably, the high-temperature exhaust gas after the reaction first enters a waste heat recovery unit to recover the waste heat before entering a steam heat exchanger to convert the heat into steam. The generated steam enters a back-pressure steam turbine to drive a generator to generate electricity, achieving power output. The exhaust steam from the turbine is then supplied to heating users, realizing the utilization of waste heat for heating. After the exhaust gas is kept under negative pressure by an induced draft fan, it enters a dust collector for purification treatment and is finally discharged through a chimney in compliance with emission standards.

[0026] As a preferred option, the HMI (Host Management Interface) system is used for parameter setting, real-time data display, alarm recording, and manual / automatic switching; the PLC (Programmable Logic Controller) system is used to receive the monitoring signals from the parameter acquisition and to perform closed-loop control and interlocking protection of the system according to the preset control logic.

[0027] Preferably, the monitoring signals include at least: CH4 concentration, O2 concentration, CO concentration, gas flow rate, air flow rate, gas inlet pressure, air inlet pressure, reactor pressure drop, inlet temperature T1, reaction zone temperature T2, outlet temperature T3, and steam pressure. Steam flow rate The PLC control system automatically adjusts the V1 valve, V2 / V3 / V4 valve, primary air fan, secondary air fan, switching valve group, induced draft fan, back pressure turbine, and generator based on the collected data. When the detected parameters exceed the preset range, the PLC automatically triggers the safety interlock module to perform alarm, load reduction, gas cut-off, bypass start, or shutdown operations to ensure the safe operation of the system.

[0028] As a preferred option, the PLC control system incorporates a built-in air distribution ratio optimization algorithm and employs a feedforward-feedback composite control strategy. The feedforward stage calculates the theoretical air demand based on the real-time collected CH4 concentration and gas flow rate Q, according to the stoichiometric relationship of complete methane combustion. The feedforward output is multiplied by the excess air coefficient. The feedforward air volume setpoint is obtained;

[0029] The feedback loop primarily controls the combustion chamber temperature T2 as the controlled variable, and the setpoint... When the measured value of T2 deviates from the set value, the PLC corrects the excess air coefficient using a PID algorithm. The air distribution ratio can be adjusted by dynamically regulating the opening of valves V2 / V3 / V4; if Prioritize reducing the air volume to decrease the dilution cooling effect; if Increase the air volume at room temperature to dilute the reaction intensity, or trigger over-temperature protection.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention achieves stable, self-sustaining operation of an ultra-low concentration methane regenerative oxidation system by real-time monitoring of methane concentration, oxygen concentration, flow rate, temperature, pressure, differential pressure, steam parameters, and generator status, combined with PLC control strategies. This is achieved through dynamic adjustment of the methane intake volume, air distribution ratio, switching cycle, intake preheating level, and turbine operating status. Furthermore, it enables the cascade utilization of waste heat from the exhaust gas for power generation and heating. Specifically, it features the following:

[0032] 1. The system adopts a skid-mounted base to support each component. The overall structure is skid-mounted, with high integration and small footprint, which facilitates transportation, installation and on-site deployment. Compared with the traditional split layout, the footprint can be reduced by more than 50% and the on-site installation cycle can be shortened by more than 60%.

[0033] 2. By setting up a regenerator to preheat the intake air, the system startup energy consumption is reduced, the inlet temperature is increased, and the system self-sustaining capability is enhanced. According to calculations, the startup energy consumption is reduced by more than 30% compared with the scheme without preheating, and the time for the system to reach self-sustaining state is shortened by more than 20%.

[0034] 3. By setting up waste heat recovery units and steam heat exchangers, the heat of the exhaust gas is utilized in stages, and a back-pressure steam turbine and generator are set up to achieve combined heat and power, thereby improving the comprehensive utilization value of energy; the overall thermal efficiency of the system is more than 15% higher than that of a single waste heat recovery scheme.

[0035] 4. The PLC enables real-time monitoring and closed-loop control of temperature, flow rate, pressure, differential pressure, and gas composition, improving system operational stability. By employing feedforward-feedback composite control, adaptive commutation, and self-sustaining state determination algorithms, the system can maintain stable operation within a gas concentration fluctuation range of ±20%, reducing commutation heat loss by more than 10%.

[0036] 5. It can achieve stable oxidation, self-sustaining operation and resource utilization of ultra-low concentration methane. Attached Figure Description

[0037] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of a skid-mounted ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system according to an embodiment of the present invention;

[0039] Figure 2 This is a block diagram of the PLC intelligent control system of the present invention;

[0040] in, Figure 1 The components are: 1. Three-chamber regenerative thermal oxidation reactor; 2. Primary air fan; 3. Secondary air fan; 4. Regenerative thermal oxidation combustion chamber; 5. Back-pressure steam turbine; 6. Waste heat recovery unit; 7. Steam heat exchanger; 8. Induced draft fan; 9. Dust collector; 10. Pretreatment unit; 11. Buffer tank; 12. Flow meter; 13. Regenerator; 14. Generator; 15. Skid-mounted base. Detailed Implementation

[0041] 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.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, this invention provides a skid-mounted, ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system, comprising:

[0045] The three-chamber regenerative oxidation reactor 1 is used for regenerative oxidation reaction of ultra-low concentration gas. It is equipped with regenerative beds A, B and C. The heat storage and release of the heat storage body are alternately cyclical through the periodic reversal of airflow between the three chambers to maintain a stable reaction temperature.

[0046] Primary air fan 2 is used to provide air distribution for the system;

[0047] Secondary air fan 3 is used to provide air distribution to the system and works in conjunction with the primary air fan to adjust the total air volume and air distribution ratio.

[0048] The regenerative oxidation combustion chamber 4 is located inside the three-chamber regenerative oxidation reactor to provide reaction space for the gas oxidation reaction;

[0049] Back-pressure steam turbine 5 is used to generate electricity and provide heat using steam.

[0050] Waste heat recovery unit 6 is used to recover waste heat from the high-temperature tail gas after the reaction.

[0051] Steam heat exchanger 7 is used to convert recovered heat into steam;

[0052] Exhaust fan 8 is used to maintain the negative pressure of the system and transport exhaust gas;

[0053] Dust collector 9 is used to purify exhaust gas;

[0054] Pretreatment device 10 is used to remove dust, dehydrate and purify methane gas;

[0055] Buffer tank 11 is used to stabilize and buffer ultra-low concentration methane at the wellhead.

[0056] Flow meter 12 is used to detect the gas flow rate entering the system;

[0057] Regenerator 13 is located on the air inlet side and is used to preheat the air before it enters the reactor;

[0058] Generator 14 is used to output electrical energy;

[0059] The skid-mounted base 15 is used to support the various components of the system and achieve overall skid-mounted integration.

[0060] In addition, the system includes: switching valve groups S1-S7, used to control the periodic reversal and airflow distribution of the three-chamber regenerative thermal oxidation reactor; valve V1, located on the inlet side of the three-chamber regenerative thermal oxidation reactor, used to regulate the gas flow rate; valves V2 / V3 / V4, respectively, are the outlet regulating valves of the regenerator 13 and the primary / secondary air fan outlet regulating valves, used to regulate the air and preheated air flow rates; valve V5, located on the outlet side of the buffer tank 11, used to control the flow rate of gas entering the pretreatment device 10 or to cut off the flow. An HMI (Human Resource Management System) and a PLC control system are used for data acquisition, operating condition identification, closed-loop regulation, and interlock protection.

[0061] The working process of this invention is as follows:

[0062] After entering the system from the wellhead, the ultra-low concentration methane gas first undergoes pressure stabilization and buffering in buffer tank 11. Then, controlled by valve V5, it enters pretreatment device 10 for dust removal, dehydration, and purification. The treated methane gas is then metered by flow meter 12 and controlled by valve V1 to enter the methane intake channel of the three-chamber regenerative thermal oxidation reactor 1. Air is supplied by primary air fan 2 and secondary air fan 3. A portion of the air is preheated by regenerator 13 before entering the air intake channel of the three-chamber regenerative thermal oxidation reactor 1 to increase the intake temperature, reduce start-up energy consumption, and enhance the system's self-sufficiency. The methane gas and preheated air enter the three-chamber regenerative thermal oxidation reactor 1 separately, where the oxidation reaction is completed in the regenerative oxidation combustion chamber 4. During the reaction, the airflow is periodically reversed via switching valves S1-S7, allowing heat exchange between the high-temperature flue gas and the regenerator, thereby maintaining a stable reactor temperature and achieving continuous oxidation. The high-temperature exhaust gas after the reaction sequentially enters the waste heat recovery unit 6 and the steam heat exchanger 7 for cascade utilization. The generated steam drives the back-pressure steam turbine 5 to drive the generator 14 to generate electricity. The exhaust steam from the steam turbine is used to supply heat to users, realizing combined heat and power (CHP). The exhaust gas is then maintained at negative pressure by the induced draft fan 8 and purified by the dust collector 9 before being discharged through the chimney in compliance with standards. The HMI upper computer monitoring system and PLC control system collect CH4, O2, CO, flow rate, temperature, pressure, differential pressure, steam parameters, fan speed, and generator status in real time, and automatically adjust the V1 valve, V2 / V3 / V4 valves, fan speed, switching valve group action, and regenerator operating status to achieve stable and self-sustaining system operation.

[0063] like Figure 2 As shown, the intelligent control part of the system includes an HMI (Host Management Interface) monitoring system and a PLC (Programmable Logic Controller) control system. The HMI monitoring system is used for parameter setting, real-time data display, alarm recording, and manual / automatic switching; the PLC control system is used to receive monitoring signals from parameter acquisition and perform closed-loop control and interlocking protection of the system according to preset control logic.

[0064] The monitoring signals include at least: CH4 concentration, O2 concentration, CO concentration, gas flow rate, air flow rate, gas inlet pressure, air inlet pressure, reactor pressure drop, inlet temperature T1, reaction zone temperature T2, outlet temperature T3, and steam pressure. Steam flow rate The system monitors the fan speed (n) and generator status. Based on the collected data, the PLC control system automatically adjusts valves V1, V2 / V3 / V4, primary air fan 2, secondary air fan 3, switching valve groups S1-S7, induced draft fan 8, back-pressure turbine 5, and generator 14. When detected parameters exceed preset ranges, the PLC automatically triggers safety interlocks, performing alarm, load reduction, gas cut-off, bypass activation, or shutdown operations to ensure safe system operation.

[0065] The intelligent control strategy is detailed below:

[0066] (1) Feedforward-feedback composite control of air distribution ratio

[0067] The PLC control system incorporates a built-in air distribution ratio optimization algorithm and employs a feedforward-feedback composite control strategy. The feedforward stage calculates the theoretical air demand based on real-time collected CH4 concentration and methane flow rate Q, according to the stoichiometric relationship for complete methane combustion. The feedforward output is then multiplied by the excess air coefficient. The feedforward air volume setpoint is obtained.

[0068] The feedback loop primarily controls the combustion chamber temperature T2 as the controlled variable, and the setpoint... When the measured value of T2 deviates from the set value, the PLC corrects the excess air coefficient using a PID algorithm. The opening degree of valves V2 / V3 / V4 is dynamically adjusted to achieve fine adjustment of the air distribution ratio. If... Prioritize reducing the air volume (to reduce the dilution cooling effect); if Increase the air volume at room temperature to dilute the reaction intensity, or trigger over-temperature protection.

[0069] (2) Adaptive reversing control of thermal regenerator bed

[0070] Traditional regenerative oxidation systems employ fixed-cycle commutation, which can easily lead to uneven heat storage or excessive commutation heat loss. This invention utilizes an adaptive commutation strategy based on temperature gradients:

[0071] The PLC indirectly evaluates the heat storage status of the thermal regeneration beds A / B / C based on T1, T2, T3 and the switching sequence. When the temperature difference between T1 and T3 exceeds the threshold... If T2 deviates from the set range, a reversal will be triggered.

[0072] During normal operation, the reversing cycle adaptively adjusts with the load: under high gas concentration conditions, the reaction releases a large amount of heat, the heat storage body stores heat quickly, and the reversing cycle is shortened; under low gas concentration conditions, the reversing cycle is extended to reduce reversing heat loss. The PLC records historical reversing data and predicts the aging or blockage trend of the heat storage body through trend analysis, providing early warning of maintenance needs.

[0073] (3) Self-sustaining operation judgment and maintenance control

[0074] The PLC has a built-in self-sustaining state evaluator that determines in real time whether the system meets the conditions for self-sustaining operation. The necessary conditions for self-sustaining operation are that the following must be met simultaneously:

[0075] 1) Temperature in the reaction zone (Self-sustaining temperature threshold);

[0076] 2) (Minimum oxidizable concentration);

[0077] 3) The O2 concentration is within the lower explosive limit safe zone;

[0078] 4) System heat balance difference .

[0079] When the above conditions are continuously met and the stable operation time exceeds The PLC determines that the system has entered a self-sustaining state. In the self-sustaining state, the PLC gradually reduces the preheating load of the regenerator, maintaining the system's thermal balance solely through reaction self-heating and waste heat recovery from the exhaust gas, achieving self-sustaining operation with zero external energy input.

[0080] If a decreasing trend in T2 occurs during operation, the PLC will respond in the following order of priority:

[0081] Level 1 response: Reduce air volume (reduce dilution cooling), adjustment range 5%~10%;

[0082] Secondary response: Increase the preheating temperature of the regenerator to increase the sensible heat of the intake air;

[0083] Level 3 response: If Continue to exceed If the self-holding is deemed to have failed, the PLC will automatically shut off the V1 valve and open the S7 bypass valve to introduce the residual gas into the safety venting pipeline, and the system will enter the safety shutdown procedure.

[0084] (4) Steam turbine load following and cogeneration optimization control

[0085] PLC uses steam pressure For the controlled variable, the set value The parameters are determined based on the turbine's rated parameters. A cascade control strategy is adopted: the main loop uses pressure control, and the secondary loop uses turbine inlet valve opening control.

[0086] When heating demand surges, the PLC detects the exhaust steam temperature, prioritizes heating, and appropriately reduces power generation. If electricity demand takes priority, the turbine's rated speed is maintained, and the heat supply is balanced by adjusting the bypass valve of the steam heat exchanger.

[0087] The dynamic priority of waste heat utilization is as follows: the first priority is to maintain the thermal balance of the reactor, the second priority is to ensure the stability of steam pressure, the third priority is to maximize the power generation efficiency, the fourth priority is to meet the heating demand, and excess heat is discharged through a bypass.

[0088] (5) Safety interlocking graded protection

[0089] The PLC is equipped with a three-level safety protection system, with the priority increasing at each level:

[0090] Warning level (yellow): When any parameter deviates from the normal value by 10%, the HMI will sound an audible and visual alarm, the PLC will record the event log, and the current operation will continue.

[0091] Reduced load level (orange): When any parameter deviates from the normal value by 20% or the CO concentration exceeds the limit, the PLC automatically reduces the load by 50%, closes V1 to 50% opening, and increases the air volume for dilution.

[0092] Shutdown level (red): When any parameter deviates from the normal value by 30%, the CH4 concentration enters the explosion limit, or the pressure difference... If an abnormal rise is detected or a gas leak is detected, the PLC will immediately execute the following actions: shut off valves V1 and V5 and open the bypass discharge valve S7; stop the primary and secondary air fans; and maintain the operation of the induced draft fan until the reactor temperature drops to a safe range and then shuts down.

[0093] All interlocking actions are recorded in a timing log to facilitate accident tracing and diagnosis.

[0094] During the startup phase, the system first preheats the intake air through the regenerator (13) and, in conjunction with the fan, circulates the heat storage medium to gradually raise the temperature of the three-chamber regenerative oxidation reactor (1) to a self-sustaining operating temperature range. The PLC then adjusts the temperature according to the system's operating parameters. The preheating load is dynamically adjusted to increase the heating rate; after entering the stable operation phase, the above-mentioned intelligent control strategy is activated; under abnormal operating conditions, safety interlock protection is implemented.

[0095] This invention achieves stable self-sustaining operation and combined heat and power of skid-mounted ultra-low concentration gas device through a tiered energy utilization mode of "intake preheating - heat storage oxidation - exhaust gas waste heat recovery - steam power generation - exhaust steam heating" combined with intelligent control and interlock protection.

[0096] Taking a coal mine exhaust gas treatment scenario as an example, the system of this invention is used for processing. In this scenario, the gas concentration at the wellhead fluctuates within a range of approximately 0.3%-0.8%, and the air volume is approximately 5000-10000 m³ / h.

[0097] The following parameters are exemplary design values. Specific values ​​need to be determined based on actual operating conditions through thermal balance calculations and on-site commissioning:

[0098] Reaction zone temperature setpoint The self-sustaining temperature threshold was determined based on the kinetics of the complete methane oxidation reaction and the temperature resistance characteristics of the heat storage body. Below Within a certain safety range, minimum oxidizable concentration The value is 0.3% (this value is calculated based on the thermal balance theory under the conditions of skid-mounted integrated structure, intake air regeneration preheating, and low heat dissipation design of this system; the specific self-sustaining lower limit needs to be corrected according to the on-site insulation conditions and actual measurement calibration), inlet temperature With outlet temperature Temperature difference threshold Stable operation determination time at 200℃ It takes 30 minutes.

[0099] During startup, the regenerator preheats the air to 200-300℃, and, in conjunction with the primary and secondary air fans, circulates the heat storage medium, raising the reaction zone temperature to its self-sustaining operating range within 1-2 hours. Once stable operation is achieved, the PLC calculates the theoretical air volume and excess air coefficient based on real-time CH4 concentration and gas flow rate Q. The initial setting is 1.2-1.5, which is dynamically corrected through a PID algorithm to dynamically adjust the opening of valves V2 / V3 / V4. The adaptive switching cycle is adjusted within the range of 90-180s according to the load: under high gas concentration conditions, the heat storage body stores heat quickly, and the switching cycle is shortened to 90-120s; under low gas concentration conditions, the switching cycle is extended to 150-180s to reduce switching heat loss.

[0100] After the exhaust gas is utilized in stages by a waste heat recovery unit and a steam heat exchanger, the steam pressure... Maintaining a pressure of 0.8-1.2 MPa, the back-pressure steam turbine generates electricity, and the exhaust steam supplies heat to the mining area. The PLC uses steam pressure as the controlled variable and adopts a cascade control strategy: the main loop is pressure control, and the secondary loop is steam turbine inlet valve opening control, dynamically allocating waste heat according to the priority of heating and power supply needs.

[0101] During system operation, the PLC monitors various parameters in real time, and the three-level safety interlock executes protective actions according to preset thresholds. When a parameter deviates from the normal value by 10%, an early warning alarm is triggered; when it deviates by 20% or the CO concentration exceeds the limit, the load is automatically reduced by 50%; when it deviates by 30%, the CH4 concentration is within the explosion limit range (5%-15%), the pressure difference is abnormally increased, or a gas leak is detected, the V1 gas valve and V5 valve are immediately shut off, and the S7 bypass discharge valve is opened. The primary and secondary air fans are shut down, and the induced draft fan is kept running until the reactor temperature drops to a safe range before shutting down.

[0102] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A skid-mounted, ultra-low concentration gas regenerative oxidation self-sustaining intelligent control system, characterized in that, include: The system includes a three-chamber regenerative thermal oxidation reactor, a primary air fan, a secondary air fan, a regenerative thermal oxidation combustion chamber, a back-pressure steam turbine, a waste heat recovery unit, a steam heat exchanger, an induced draft fan, a dust collector, a pretreatment unit, a buffer tank, a flow meter, a regenerator, a generator, and a skid-mounted base. A switching valve assembly is used to control the periodic reversal and airflow distribution of the three-chamber regenerative thermal oxidation reactor. A gas regulating valve (V1), located at the inlet side of the three-chamber regenerative thermal oxidation reactor, is used to regulate the gas flow rate. Air regulating valves one (V2), two (V3), and three (V4) are respectively the regenerator outlet regulating valve and the primary / secondary air fan outlet regulating valve, used to regulate the air and preheated air flow rates. A gas valve (V5), located at the buffer tank outlet side, is used to control the flow rate of gas entering the pretreatment unit or to cut off the flow. An HMI (Human Resource Management System) is used for parameter setting, real-time data display, alarm recording, and manual / automatic switching. The PLC control system is used to receive monitoring signals from parameter acquisition and to perform closed-loop control and interlock protection of the system according to preset control logic. The three-chamber regenerative thermal oxidation reactor is equipped with regenerative beds 1 (A), 2 (B), and 3 (C). The regenerative oxidation combustion chamber is located inside the three-chamber regenerative thermal oxidation reactor. The buffer tank is connected in sequence to the gas valve (V5), pretreatment device, flow meter, gas regulating valve (V1), and the three-chamber regenerative thermal oxidation reactor. The primary and secondary air fans are connected to the regenerators respectively. The hot air from the regenerators enters the three-chamber regenerative thermal oxidation reactor for combustion support. The flue gas from the three-chamber regenerative thermal oxidation reactor passes in sequence through the waste heat recovery unit, steam heat exchanger, induced draft fan, and dust collector, and is finally discharged from the chimney. The steam generated by heating the flue gas waste heat in the steam heat exchanger enters the back-pressure steam turbine to expand and do work, driving the rotor to rotate and drive the generator to generate electricity. The PLC control system incorporates a built-in air distribution ratio optimization algorithm and employs a feedforward-feedback composite control strategy. The feedforward stage calculates the theoretical air demand based on the real-time collected CH4 concentration and gas flow rate (Q) according to the stoichiometric relationship of complete methane combustion. The feedforward output is multiplied by the excess air coefficient (…). ), to obtain the feedforward air volume setpoint; The feedback loop primarily controls the combustion chamber temperature (T2), with the setpoint as the main controlled variable. When the measured combustion chamber temperature (T2) deviates from the set value, the PLC corrects the excess air coefficient using a PID algorithm. The opening degree of air conditioning valve 1 (V2), air conditioning valve 2 (V3), and air conditioning valve 3 (V4) is dynamically adjusted to achieve air distribution ratio regulation; if This reduces the air volume of the primary and secondary air fans, thus lowering the dilution cooling effect. like Increase the air volume at room temperature to dilute the reaction intensity, or trigger over-temperature protection; The monitoring signals include at least: CH4 concentration, O2 concentration, CO concentration, gas flow rate, air flow rate, gas inlet pressure, air inlet pressure, reactor pressure drop, inlet temperature (T1), combustion chamber temperature (T2), outlet temperature (T3), and steam pressure (…). ), steam flow rate ( The PLC control system collects data on the following parameters: fan speed (n) and generator status. Based on this data, the PLC automatically adjusts the gas regulating valve (V1), air regulating valve one (V2), air regulating valve two (V3), air regulating valve three (V4), primary air fan, secondary air fan, switching valve group, induced draft fan, back pressure turbine, and generator. When the detected parameters exceed the preset range, the PLC automatically triggers the safety interlock module to perform alarm, load reduction, gas cut-off, bypass start, or shutdown operations to ensure the safe operation of the system.

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