One-to-two mode intelligent switching system and method for combined supply of thermal inert gas

Abstract

The invention relates to the technical field of industrial hot air supply and waste gas recovery, and discloses a one-to-two mode intelligent switching system and method for combined supply of hot inert gas. According to the system, low-heat-value waste gas is treated through a super-adiabatic combustion device, and high-temperature flue gas is generated and mixed with circulating air to form hot inert gas; intelligent switching and independent supply of thermal inert gas to two original hot air systems are realized by adopting a three-valve group and a nitrogen plugging pipeline; a high-pressure CO2 storage tank and a multi-stage pressure reducing device are integrated, and when parameters exceed limits, inert gas for deep cooling is injected to implement emergency temperature control and inerting; the temperature, the pressure, the flow and the oxygen content are monitored in real time through the interlocking control module, and gas supply path switching and emergency response are automatically executed. By means of an integrated intelligent control framework, the problems that a traditional system is high in redundancy, tedious in switching and weak in emergency capacity are solved, and efficient recovery of low-heating-value waste gas and safe, flexible and reliable operation of a hot air supply system are achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial thermal process control and energy recovery technology, and particularly to a one-to-two mode intelligent switching system and method for combined thermal inert gas supply. Background Technology

[0002] Current hot air supply systems primarily focus on utilizing syngas or conventional fuels as heat sources, supplying hot air to downstream heat-consuming equipment through a one-to-one hot air furnace configuration. A typical approach involves a pulverized coal gasification unit where, after scrubbing and purification, a portion of the syngas is sent to a hot air furnace for combustion, heating the circulating process gas to generate high-temperature hot air. The system typically employs multiple hot air furnaces operating in parallel, each equipped with an independent burner and fuel supply system, forming a "one furnace for one use" supply model. Furthermore, to ensure system safety, some units incorporate a flare system to treat unusable low-calorific-value waste gas, directly burning and discharging it.

[0003] The core problems of existing technologies are system redundancy and energy waste, namely, rigid hot air supply modes, ineffective utilization of low-calorific-value waste gas, and a lack of intelligent emergency temperature control mechanisms. Specifically, this manifests as: a single fuel structure and high syngas consumption: existing hot air furnaces rely on syngas or diesel as fuel, directly reducing the amount of syngas available for main products such as ammonia synthesis, impacting overall production efficiency; redundant system configuration and complex switching: adopting a "one furnace for one use" model requires multiple hot air furnaces and their supporting systems, resulting in high equipment investment, large footprint, and cumbersome start-up and switching processes, leading to poor system flexibility; inefficient utilization of low-calorific-value waste gas: low-calorific-value combustible waste gases such as liquid nitrogen scrubbing tail gas and flash vapor generated within the plant area are mostly sent to the flare for combustion and emission, neither recovering their calorific value nor achieving environmental treatment, resulting in energy waste and environmental pollution; and a lack of integrated emergency temperature control and inert gas protection mechanisms: existing systems lack dedicated emergency temperature control and inert gas replenishment systems, relying on nitrogen and other gas sources within the plant area, which cannot quickly achieve cooling, oxygen reduction, and system protection in emergencies, posing safety hazards. These problems result in significant shortcomings in the existing hot air supply system in terms of economy, energy efficiency, environmental protection, and safety, making it unable to meet the development needs of modern chemical enterprises for energy conservation, carbon reduction, recycling, and intelligent control. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the core issues of existing technology are system redundancy and energy waste, namely, rigid hot air supply mode, failure to effectively utilize low calorific value waste gas, and lack of intelligent emergency temperature control mechanism. To address this, we propose a one-to-two mode intelligent switching system and method for combined hot and inert gas supply.

[0005] To achieve the above objectives, this application adopts the following technical solution: a one-to-two mode intelligent switching method for combined thermal inert gas supply, comprising the following steps: S1, the low-calorific-value exhaust gas is premixed with air to form a premixed gas, which is then transported to an ultra-insulated combustion device for combustion, ensuring high thermal efficiency and combustion stability to generate high-temperature flue gas. The low-calorific-value exhaust gas is PSA tail gas. The ultra-insulated combustion device achieves self-sustaining combustion without the need for auxiliary fuel.

[0006] S2, the high-temperature flue gas and circulating air are mixed in the mixing section to form a hot inert gas that meets the set temperature and flow requirements. The circulating air comes from the circulating fan of the original hot blast stove system and is transported to the downstream coal mill.

[0007] S3, through a pipeline system equipped with a three-valve group and a nitrogen plugging structure, the thermal inert gas is selectively distributed to the two original hot air system pipelines, so that one ultra-insulated combustion device can simultaneously or alternately supply gas to the two hot air systems independently, and the two systems do not cross-flow or interfere with each other.

[0008] S4, real-time monitoring of the temperature, pressure, flow rate and oxygen content parameters of the hot inert gas. When any parameter exceeds the preset safety threshold, interlock control is triggered to start the high-pressure CO2 emergency inertization program. The high-pressure CO2 emergency inertization program includes extracting CO2 from the high-pressure CO2 storage device, cooling the CO2 through a multi-stage pressure reducing device, and injecting it into the hot inert gas pipeline or the mixing section of the combustion device to achieve rapid cooling, inertization and oxygen content control.

[0009] S5 continuously monitors the system's operating status and key performance indicators, including hot air temperature stability, flow rate stability, oxygen content safety limits, and low-calorific-value exhaust gas treatment efficiency. When indicators are abnormal, it automatically adjusts operating parameters or performs system switching and emergency response to ensure the system operates safely, stably, and efficiently.

[0010] To achieve the above objectives, this application adopts the following technical solution: a one-to-two mode intelligent switching system for combined thermal inert gas supply, characterized in that it includes: The ultra-insulated combustion and waste gas treatment module receives at least one low-calorific-value waste gas from the following sources within the plant area: liquid nitrogen scrubbing tail gas, flash vapor, vent air from the phenol-ammonia recovery system, and refrigeration tail gas from the nitrogen fertilizer unit, as well as combustion air. It premixes the low-calorific-value waste gas with air to form a premixed gas, which is then transported to the ultra-insulated combustion device for self-heating combustion, outputting high-temperature flue gas for mixing with circulating air. By setting up the ultra-insulated combustion device and utilizing multiple low-calorific-value waste gases, including liquid nitrogen scrubbing tail gas, as fuel, the module addresses the problems of a single fuel structure, high syngas consumption, and inefficient utilization of low-calorific-value waste gases, achieving the effects of saving syngas, recovering waste gas heat energy, and realizing environmental protection.

[0011] The intelligent switching and hot air distribution module receives high-temperature flue gas from the ultra-insulated combustion and exhaust gas treatment module, as well as circulating air from the original hot air furnace system. It mixes the high-temperature flue gas and circulating air in the mixing section to generate hot inert gas with the required temperature and flow rate. It is also equipped with a pipeline system including a three-valve group and a nitrogen plugging structure to selectively distribute and independently deliver the hot inert gas to at least one of the two original hot air pipelines. This is achieved by using an ultra-insulated combustion device in conjunction with a distribution pipeline with a three-valve group and nitrogen plugging.

[0012] The emergency inerting and temperature control module receives liquid or high-pressure CO2 gas from the high-pressure CO2 storage device when the system detects abnormalities in temperature, pressure, or oxygen content. It then reduces the pressure and temperature of the CO2 through a multi-stage pressure reduction device and injects the low-temperature CO2 gas into the hot inert gas pipeline or the mixing section of the combustion device. By setting up a high-pressure CO2 storage device and a multi-stage pressure reduction and cooling unit, it provides a backup inert gas source with low-temperature characteristics to solve the problem of lacking an integrated emergency temperature control and inert protection mechanism.

[0013] The parameter acquisition and interlock control module collects real-time parameters of the temperature, pressure, flow rate, and oxygen content of the hot inert gas in the system, as well as the operating status of the combustion device. It receives operating data from the intelligent switching and hot air distribution module and the emergency inerting and temperature control module. Based on preset safety thresholds and logic, it sends switching commands to the valves in the intelligent switching and hot air distribution module and opening commands to the injection valves in the emergency inerting and temperature control module. Through the integrated sensor network and control system, it monitors the calorific value, gas volume, pressure, and oxygen content in real time and executes safety interlocks.

[0014] Furthermore, the control process for ensuring high thermal efficiency and combustion stability specifically performs the following operations: It receives real-time component data or calorific value signals of low-calorific-value exhaust gas, as well as flame state signals and flue gas oxygen content data within the combustion device. Through a combustion optimization control model, it calculates the target air-fuel ratio and auxiliary fuel compensation amount, dynamically adjusts the opening of the combustion air flow valve and the exhaust gas premixing proportion valve, and fine-tunes the total fuel supply based on the deviation between the combustion temperature feedback and the set temperature, so that the combustion temperature is stabilized within the set range and the flue gas oxygen content is kept within the optimal range.

[0015] Preferably, step S3 includes the following sub-steps: S31, receiving hot inert gas from the mixing section.

[0016] S32, through a distribution pipeline structure including parallel valve groups and isolation mechanisms, the thermal inert gas is distributed to two independent hot air pipelines, wherein the isolation mechanism is configured to inject a sealing medium into the valve seal or the middle section of the pipeline during valve group switching or when the pipeline is not in use, so as to establish a physical isolation anti-cross-flow mechanism.

[0017] S33, in response to instructions from the control system, operates the opening and closing state of the valve group to achieve the switching of thermal inert gas between the two pipelines.

[0018] S34, after the switch is completed or during non-gas supply periods, maintain the non-gas supply pipeline in the pressure-holding state of the sealing medium to ensure that the two hot air systems operate independently.

[0019] Furthermore, the isolation mechanism injects a sealing medium into the valve seal or the middle section of the pipeline to establish a physical isolation and anti-cross-flow mechanism, specifically by performing the following operations: The system monitors and calculates the real-time pressure difference between the target isolation section and the non-supply section. Based on the pressure difference and the target back pressure setpoint of the sealing medium, an adaptive pressure control algorithm dynamically adjusts the injection flow rate of the sealing medium. This algorithm aims to dynamically track the back pressure at the sealing point to overcome pressure difference disturbances and ensure absolute sealing of the sealing interface under any pressure difference fluctuation. A high-precision pressure sensor verifies that the internal pressure of the isolation section is stable within the preset inert atmosphere pressure window, and the flow rate of the sealing medium is continuously monitored. If the flow rate is consistently higher than the leakage judgment threshold, a high-level alarm is triggered and the backup isolation plan is executed. The entire dynamic control process ensures the reliability and robustness of the physical isolation barrier during thermal inert gas pressure fluctuations or transient switching. The adaptive pressure control algorithm formula is as follows: , in, Let t be the injection volume flow rate of the sealing medium. for Pressure control deviation at any time This is the static back pressure setting value. This is the differential pressure compensation coefficient. for Constantly monitor the instantaneous pressure difference between the isolated pipe section and the external pipe section. for Real-time back pressure measurement at the sealing point. , , The proportional, integral, and derivative control gains are respectively set based on the medium characteristics and pipeline response time. , These are the coefficients of the nonlinear compensation term, used for rapid response to large pressure differential changes. The density of the sealing medium under operating conditions, It is a hyperbolic tangent function used to smooth nonlinear terms and prevent over-adjustment.

[0020] Furthermore, the proportional control gain, integral control gain, derivative control gain, and nonlinear compensation coefficient in the adaptive pressure control algorithm are dynamic parameters that are self-tuned online based on the real-time operating conditions of the system. The absolute value of the pressure change rate of the target isolation pipe section and the historical fluctuation variance of the flow rate of the sealing medium are acquired in real time as characteristic quantities to characterize the intensity of system disturbance. Based on these characteristic quantities, the control gain and nonlinear compensation coefficient for the next control cycle are calculated and updated in real time through a parameter dynamic mapping model. In high disturbance conditions with drastic pressure changes or increased flow fluctuations, the differential control gain and nonlinear compensation coefficient are automatically increased to enhance the system damping and rapid disturbance rejection capability. At the same time, in low disturbance conditions with stable pressure, the integral control gain is automatically increased to eliminate static errors.

[0021] Furthermore, the process of allowing the inert gas to flow through a multi-stage pressure reducing device to achieve deep cooling through isenthalpic expansion specifically involves the following operations: Based on the real-time pressure and temperature of the inert gas in the high-pressure storage device, as well as the target injection pressure and desired outlet temperature, the optimal number of depressurization stages and the distribution strategy of intermediate pressures at each stage are calculated online using a gas thermodynamic model. Based on this strategy, the opening sequence of the pressure-reducing valves at each stage and the activation status of the interstage coolers are dynamically configured to ensure that the gas undergoes an almost ideal isenthalpic expansion process at each stage. The deviation between the high-response temperature sensor reading at the final stage outlet and the target outlet temperature is fed back to the pre-temperature control logic of the first-stage pressure-reducing valve. This pre-temperature control logic is a closed-loop control algorithm that makes subtle, forward-looking adjustments to the opening of the first-stage pressure-reducing valve based on the measured temperature at the final stage outlet of the multi-stage pressure-reducing device, forming a closed-loop temperature shaping loop to counteract the effects of minor changes in gas composition or valve characteristic drift.

[0022] Preferably, step S4 includes the following sub-steps: S41 collects real-time parameters of temperature, pressure, flow rate, and oxygen content of the hot inert gas.

[0023] S42, determine whether any of the parameters exceeds a preset safety threshold.

[0024] S43, when the judgment parameter exceeds the limit, inert gas is extracted from the high-pressure storage device.

[0025] S44, the inert gas is allowed to flow through a multi-stage pressure reducing device, and deep cooling is achieved through isenthalpic expansion, reducing its temperature to a predetermined low temperature range.

[0026] S45, the cooled inert gas is injected into the hot inert gas pipeline or the mixing section of the combustion device through a targeted injection point.

[0027] Furthermore, the method of injecting the cooled inert gas through a targeted injection point specifically involves the following operations: A multi-dimensional fault state matrix is ​​constructed, incorporating temperature, flow rate, oxygen content, and flame state signals of the mixing section of the superadiabatic combustion device at key nodes of the thermal inert gas pipeline network. A decision model based on fuzzy logic and real-time thermodynamic simulation is used to diagnose and assess the severity of current fault modes, including local overheating, sudden oxygen content increase, and flameout risk. Based on this, one or more optimal combination injection points are dynamically selected from a set of preset physical injection points, including the upstream of the main mixing section, the high-temperature flue gas pipeline, and the hot air main pipeline near the coal mill. Based on the gas mixing and heat transfer characteristic model downstream of the selected injection points, the required inert gas distribution flow rate to achieve optimal cooling and inertization effects is calculated. Non-uniform flow distribution is implemented through independent high-speed regulating valves at each injection point, ensuring that the inertizing medium extinguishes risk points with the shortest path and highest efficiency within the system, while minimizing disturbance to normal production processes. The decision model formula for optimal injection point selection and flow distribution is as follows: , , in, This is a comprehensive evaluation index; a higher value indicates a better decision. For the quantity of benefit dimensions, such as cooling rate, inerting uniformity, and response time, For the first The dynamic weights of each benefit dimension are determined by the severity of the fault. For the first A benefit function, It is a sensor signal via state estimation function The obtained system state vector, such as the superheat at each point and the proximity to the explosion limit, It is 3D binary vector, representing The enabled status of potential injection points Quantities related to cost, such as inert gas consumption and process disturbance. For the first Penalty coefficient for each cost dimension For the first A cost function It is a K-dimensional vector representing the traffic allocated to each enabled injection point. , The matrix and vector are used to define linear constraints such as total inert gas supply capacity and maximum flow rate of a single valve.

[0028] Furthermore, based on the switching command from the control system or the determination parameter, the following operations are performed: A deep learning prediction model, such as an LSTM network, integrating time-series data on calorific value, flow rate, and pressure, is established to predict future trends of key parameters of thermal inert gas, such as temperature and oxygen content, in advance. During normal system operation, the model runs continuously. If it predicts that a parameter will exceed its safety threshold within a future time window, or predicts that the gas supply demand will change significantly, it generates a pre-switching command in advance. This pre-starts the pre-cooling of the high-pressure inert gas supply pipeline, or pre-adjusts the three-valve group to the standby state, or slightly increases the pressure of the sealing medium in advance. This minimizes the "perception-decision-execution" delay in emergency response or mode switching, achieving a leap from passive response to proactive predictive protection, and greatly improving the smoothness and safety of the system in dealing with sudden operating conditions.

[0029] The technical effects and advantages of this invention are as follows: Based on my understanding of the technical solution of this patent, and following the template you provided, the beneficial effects are as follows: 1. In this invention, by constructing a one-to-two intelligent distribution pipeline with an ultra-insulated combustion device as the core and integrating a three-valve group and a nitrogen plugging structure, flexible, independent gas supply and rapid switching from a single heat source to two original hot air systems are realized. This solves the problems of system redundancy, high equipment investment and cumbersome switching operations caused by the traditional one-to-one furnace mode, thereby significantly reducing construction and operation costs and improving the overall reliability and operational flexibility of the hot air supply system.

[0030] 2. In this invention, by setting up a high-pressure CO2 emergency inerting system equipped with a multi-stage pressure reduction device and establishing a safety interlock control logic based on real-time parameters, it is possible to quickly inject deeply cooled inert gas when the system is overheated, overpressured, or has abnormal oxygen content. This solves the problems of traditional systems lacking efficient emergency temperature control and inerting protection methods and relying on external gas sources, resulting in slow response. This greatly enhances the intrinsic safety of the system under accident conditions and ensures the stable operation of the production unit.

[0031] 3. In this invention, by using an interlocking control module to collect and analyze multi-dimensional parameters such as temperature, pressure, flow rate and oxygen content of the hot inert gas in real time, and automatically execute gas supply path switching or emergency inertization injection based on preset logic, the entire system achieves automated monitoring and intelligent decision-making, solving the problems of lagging manual monitoring and reliance on experience in operation. Thus, while achieving energy-saving and environmental protection goals, the safety, efficiency and stability of the entire hot air supply process are ensured. Attached Figure Description

[0032] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a system block diagram of the present invention; Figure 3 This is a schematic diagram of the main architecture of a specific implementation example system of the present invention. Detailed Implementation

[0033] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0034] Reference Figure 1 As shown, the present invention provides a technical solution: a one-to-two mode intelligent switching method for combined thermal inert gas supply, comprising the following steps: S1 receives PSA exhaust gas and air, mixes them in a premixer to form premixed gas, and then sends the premixed gas to an ultra-insulated combustion device for combustion, ensuring high thermal efficiency and combustion stability to produce high-temperature flue gas. The PSA exhaust gas contains at least one low-calorific-value waste gas from liquid nitrogen scrubbing exhaust gas, flash vapor, vent gas from the phenol recovery ammonia system, and refrigeration exhaust gas from the nitrogen fertilizer unit. The ultra-insulated combustion device achieves self-sustaining combustion without the need for auxiliary fuel, with a thermal efficiency ≥95%.

[0035] S2, the high-temperature flue gas and circulating air are mixed in the mixing section to form a hot inert gas that meets the set temperature and flow requirements. The circulating air comes from the circulating fan of the original hot blast stove system. The temperature of the hot inert gas is controlled between 340℃ and 350℃, the flow rate is stable at 77000 Nm³ / h, and it is transported to the downstream coal mill through a DN1500 pipeline.

[0036] S3, through a pipeline system equipped with a three-valve group and a nitrogen plugging structure, the thermal inert gas is selectively distributed to the two original hot air system pipelines, so that one ultra-insulated combustion device can simultaneously or alternately supply gas to the two hot air systems independently, and the two systems do not cross-flow or interfere with each other.

[0037] S4, real-time monitoring of the temperature, pressure, flow rate, and oxygen content parameters of the hot inert gas. When any parameter exceeds the preset safety threshold, interlock control is triggered to start the high-pressure CO2 emergency inertization program. The high-pressure CO2 emergency inertization program includes extracting CO2 from the high-pressure CO2 storage device, reducing the CO2 temperature from 60℃~85℃ to -47℃~-31℃ through a multi-stage pressure reducing device, and injecting the cooled CO2 into the hot inert gas pipeline or the mixing section of the combustion device to achieve rapid cooling, inertization, and oxygen content control.

[0038] S5 continuously monitors the system's operating status and key performance indicators, including hot air temperature stability, flow rate stability, oxygen content safety limits, and low-calorific-value exhaust gas treatment efficiency. When indicators are abnormal, it automatically adjusts operating parameters or performs system switching and emergency response to ensure the system operates safely, stably, and efficiently.

[0039] Reference Figure 2 As shown, a one-to-two mode intelligent switching system for combined thermal inert gas supply is characterized by comprising: The ultra-insulated combustion and waste gas treatment module receives at least one low-calorific-value waste gas from the following sources within the plant area: liquid nitrogen scrubbing tail gas, flash vapor, vent air from the phenol-ammonia recovery system, and refrigeration tail gas from the nitrogen fertilizer unit, as well as combustion air. It premixes the low-calorific-value waste gas with air to form a premixed gas, which is then transported to the ultra-insulated combustion device for self-heating combustion, outputting high-temperature flue gas for mixing with circulating air. By setting up the ultra-insulated combustion device and utilizing multiple low-calorific-value waste gases, including liquid nitrogen scrubbing tail gas, as fuel, the module addresses the problems of a single fuel structure, high syngas consumption, and inefficient utilization of low-calorific-value waste gases, achieving the effects of saving syngas, recovering waste gas heat energy, and realizing environmental protection.

[0040] The intelligent switching and hot air distribution module receives high-temperature flue gas from the ultra-insulated combustion and exhaust gas treatment module, as well as circulating air from the original hot air furnace system. It mixes the high-temperature flue gas and circulating air in the mixing section to generate hot inert gas with the required temperature and flow rate. It is also equipped with a pipeline system including a three-valve group and a nitrogen plugging structure to selectively distribute and independently deliver the hot inert gas to at least one of the two original hot air pipelines. This is achieved by using an ultra-insulated combustion device in conjunction with a distribution pipeline with a three-valve group and nitrogen plugging.

[0041] The emergency inerting and temperature control module receives liquid or high-pressure CO2 gas from the high-pressure CO2 storage device when the system detects abnormalities in temperature, pressure, or oxygen content. It then reduces the pressure and temperature of the CO2 through a multi-stage pressure reduction device and injects the low-temperature CO2 gas into the hot inert gas pipeline or the mixing section of the combustion device. By setting up a high-pressure CO2 storage device and a multi-stage pressure reduction and cooling unit, it provides a backup inert gas source with low-temperature characteristics to solve the problem of lacking an integrated emergency temperature control and inert protection mechanism.

[0042] The parameter acquisition and interlock control module collects real-time parameters of the temperature, pressure, flow rate, and oxygen content of the hot inert gas in the system, as well as the operating status of the combustion device. It receives operating data from the intelligent switching and hot air distribution module and the emergency inerting and temperature control module. Based on preset safety thresholds and logic, it sends switching commands to the valves in the intelligent switching and hot air distribution module and opening commands to the injection valves in the emergency inerting and temperature control module. Through the integrated sensor network and control system, it monitors the calorific value, gas volume, pressure, and oxygen content in real time and executes safety interlocks.

[0043] Furthermore, the control process for ensuring high thermal efficiency and combustion stability specifically performs the following operations: It receives real-time component data or calorific value signals of low-calorific-value exhaust gas, as well as flame state signals and flue gas oxygen content data within the combustion device. Through a combustion optimization control model, it calculates the target air-fuel ratio and auxiliary fuel compensation amount, dynamically adjusts the opening of the combustion air flow valve and the exhaust gas premixing proportion valve, and fine-tunes the total fuel supply based on the deviation between the combustion temperature feedback and the set temperature. This ensures that the combustion temperature remains stable within the set range and the flue gas oxygen content is kept within the optimal range, achieving a thermal efficiency of no less than 95% and stable self-heating operation without auxiliary fuel.

[0044] Preferably, step S3 includes the following sub-steps: S31, receiving hot inert gas from the mixing section.

[0045] S32, through a distribution pipeline structure including parallel valve groups and isolation mechanisms, the thermal inert gas is distributed to two independent hot air pipelines, wherein the isolation mechanism is configured to inject a sealing medium into the valve seal or the middle section of the pipeline during valve group switching or when the pipeline is not in use, so as to establish a physical isolation anti-cross-flow mechanism.

[0046] S33, in response to instructions from the control system, operates the opening and closing state of the valve group to achieve the switching of thermal inert gas between the two pipelines.

[0047] S34, after the switch is completed or during non-gas supply periods, maintain the non-gas supply pipeline in the pressure-holding state of the sealing medium to ensure that the two hot air systems operate independently.

[0048] Furthermore, the isolation mechanism injects a sealing medium into the valve seal or the middle section of the pipeline to establish a physical isolation and anti-cross-flow mechanism, specifically by performing the following operations: The system monitors and calculates the real-time pressure difference between the target isolation section and the non-supply section. Based on the pressure difference and the target back pressure setpoint of the sealing medium, an adaptive pressure control algorithm dynamically adjusts the injection flow rate of the sealing medium. This algorithm aims to dynamically track the back pressure at the sealing point to overcome pressure difference disturbances and ensure absolute sealing of the sealing interface under any pressure difference fluctuation. A high-precision pressure sensor verifies that the internal pressure of the isolation section is stable within the preset inert atmosphere pressure window, and the flow rate of the sealing medium is continuously monitored. If the flow rate is continuously higher than the leakage judgment threshold, a high-level alarm is triggered and the backup isolation plan is executed. The entire dynamic control process ensures the reliability and robustness of the physical isolation barrier during thermal inert gas pressure fluctuations or transient switching.

[0049] Specifically, the adaptive pressure control algorithm formula is obtained through the following steps: Step 1, the core control objective of the physical isolation anti-cross-flow mechanism, is to dynamically track a set target back pressure at the actual back pressure at the sealing point, ensuring that the sealing interface remains absolutely sealed under different pressure differential disturbances. The target back pressure is set as follows: , In the formula, This is the static back pressure setpoint, which is a constant. for Constantly monitor the instantaneous pressure difference between the isolation pipeline section and the non-supply pipeline section. This is the differential pressure compensation coefficient, used to adjust the target back pressure in advance according to the magnitude of the differential pressure, so as to offset the impact of the differential pressure on the sealing effect.

[0050] Step 2, define the pressure control deviation at time t. for: , In the formula, for The measured back pressure at the closure point at all times. The control objective is to make... Approaching zero.

[0051] Step 3: To accurately and quickly adjust the injection flow rate of the sealing medium. The controller output is designed as a classic proportional-integral-derivative (PID) control term. With a nonlinear feedforward compensation term sum: .

[0052] Step 4, PID control term based on deviation Adjusting for its historical and future trends, its expression is: , In the formula, , , These are the proportional, integral, and derivative control gains, respectively. The proportional term reacts immediately to the current deviation, the integral term eliminates historically accumulated static errors, and the derivative term makes advance adjustments based on the deviation change trend to suppress system oscillations.

[0053] Step 5, when the pressure difference To enhance the system's rapid disturbance rejection capability and avoid potential lag in PID control during drastic or large-scale changes, a nonlinear feedforward compensation term based on pressure difference is introduced. This compensation term must meet two characteristics: first, the compensation intensity should be related to the absolute value of the pressure difference; second, it should be a continuous and smooth function to prevent sudden changes in the command. Analysis shows that the compensation flow rate... and Proportional, of which To address the density of the blocking medium, ensure a smooth transition, and limit the maximum compensation, a hyperbolic tangent function is introduced. After processing the differential pressure signal, the final nonlinear feedforward compensation term is designed as follows: , In the formula, and The nonlinear compensation coefficient is represented by the hyperbolic tangent function, which maps the differential pressure signal to the interval [-1, 1], ensuring the smoothness of the compensation action.

[0054] Step 6: Based on the above derivation, the complete formula for the adaptive pressure control algorithm of the plugging medium injection flow rate is obtained: .

[0055] Furthermore, the proportional control gain, integral control gain, derivative control gain, and nonlinear compensation coefficient in the adaptive pressure control algorithm are dynamic parameters that are self-tuned online based on the real-time operating conditions of the system. The absolute value of the pressure change rate of the target isolation pipe section and the historical fluctuation variance of the flow rate of the sealing medium are acquired in real time as characteristic quantities to characterize the intensity of system disturbance. Based on these characteristic quantities, the control gain and nonlinear compensation coefficient for the next control cycle are calculated and updated in real time through a parameter dynamic mapping model. In high disturbance conditions with drastic pressure changes or increased flow fluctuations, the differential control gain and nonlinear compensation coefficient are automatically increased to enhance the system damping and rapid disturbance rejection capability. At the same time, in low disturbance conditions with stable pressure, the integral control gain is automatically increased to eliminate static errors.

[0056] Furthermore, the process of allowing the inert gas to flow through a multi-stage pressure reducing device to achieve deep cooling through isenthalpic expansion specifically involves the following operations: Based on the real-time pressure and temperature of the inert gas in the high-pressure storage device, as well as the target injection pressure and desired outlet temperature, the optimal number of depressurization stages and the distribution strategy of intermediate pressures at each stage are calculated online using a gas thermodynamic model. Based on this strategy, the opening sequence of the pressure-reducing valves at each stage and the activation status of the interstage coolers are dynamically configured to ensure that the gas undergoes an almost ideal isenthalpic expansion process at each stage. The deviation between the high-response temperature sensor reading at the final stage outlet and the target outlet temperature is fed back to the pre-temperature control logic of the first-stage pressure-reducing valve. This pre-temperature control logic is a closed-loop control algorithm that makes subtle, forward-looking adjustments to the opening of the first-stage pressure-reducing valve based on the measured temperature at the final stage outlet of the multi-stage pressure-reducing device, forming a closed-loop temperature shaping loop to counteract the effects of minor changes in gas composition or valve characteristic drift.

[0057] Preferably, step S4 includes the following sub-steps: S41 collects real-time parameters of temperature, pressure, flow rate, and oxygen content of the hot inert gas.

[0058] S42, determine whether any of the parameters exceeds a preset safety threshold.

[0059] S43, when the judgment parameter exceeds the limit, inert gas is extracted from the high-pressure storage device.

[0060] S44, the inert gas is allowed to flow through a multi-stage pressure reducing device, and deep cooling is achieved through isenthalpic expansion, reducing its temperature to a predetermined low temperature range.

[0061] S45, the cooled inert gas is injected into the hot inert gas pipeline or the mixing section of the combustion device through a targeted injection point.

[0062] Furthermore, the method of injecting the cooled inert gas through a targeted injection point specifically involves the following operations: A multi-dimensional fault state matrix is ​​constructed, incorporating temperature, flow rate, oxygen content, and flame state signals of the mixing section of the superadiabatic combustion device at key nodes of the thermal inert gas pipeline network. A decision model based on fuzzy logic and real-time thermodynamic simulation is used to diagnose and assess the severity of current fault modes, including local overheating, sudden oxygen content increase, and flameout risk. Based on this, one or more optimal combination injection points are dynamically selected from a set of preset physical injection points, including the upstream of the main mixing section, the high-temperature flue gas pipeline, and the hot air main pipeline near the coal mill. Based on the gas mixing and heat transfer characteristic model downstream of the selected injection points, the required inert gas distribution flow rate to achieve optimal cooling and inertization effects is calculated. Non-uniform flow distribution is implemented through independent high-speed regulating valves at each injection point, ensuring that the inertizing medium extinguishes risk points with the shortest path and highest efficiency within the system, while minimizing disturbance to normal production processes. The decision model formula for optimal injection point selection and flow distribution is as follows: , , in, This is a comprehensive evaluation index; a higher value indicates a better decision. For the quantity of benefit dimensions, such as cooling rate, inerting uniformity, and response time, For the first The dynamic weights of each benefit dimension are determined by the severity of the fault. For the first A benefit function, It is a sensor signal via state estimation function The obtained system state vector, such as the superheat at each point and the proximity to the explosion limit, It is 3D binary vector, representing The enabled status of potential injection points Quantities related to cost, such as inert gas consumption and process disturbance. For the first Penalty coefficient for each cost dimension For the first A cost function It is a K-dimensional vector representing the traffic allocated to each enabled injection point. , The matrix and vector are used to define linear constraints such as total inert gas supply capacity and maximum flow rate of a single valve.

[0063] Furthermore, based on the switching command from the control system or the determination parameter, the following operations are performed: A deep learning prediction model, such as an LSTM network, integrating time-series data on calorific value, flow rate, and pressure is established to predict future trends of key parameters of thermal inert gas, such as temperature and oxygen content, in advance. During normal system operation, the model runs continuously. If it predicts that a parameter will exceed its safety threshold within a future time window, or predicts that the gas supply demand will change significantly, it generates a pre-switching command in advance. This pre-starts the pre-cooling of the high-pressure inert gas supply pipeline, or pre-adjusts the three-valve group to the standby state, or slightly increases the pressure of the sealing medium in advance, thereby minimizing the perception-decision-execution delay of emergency response or mode switching.

[0064] In this embodiment, as Figure 3 As shown, the intelligent switching logic is as follows: During normal system operation, the interlock control module continuously monitors and analyzes the temperature, pressure, flow rate, and oxygen content parameters from key measuring points at the mixing section outlet and the two original hot air pipelines.

[0065] When a switching command is received from the process or when a switching is predicted by a predictive model, the control system first confirms that the target gas supply pipeline is ready to receive the command. The switching command may be due to planned maintenance, load adjustment, or a pipeline failure.

[0066] Initiate the switching procedure: Send instructions to the hot air generation and distribution module to operate the opening and closing status of the corresponding valves in the three-valve group, and gradually guide the mainstream of hot inert gas from the current gas supply pipeline to the target pipeline.

[0067] Meanwhile, to absolutely prevent gas crosstalk between the two pipelines, the isolation mechanism is activated, injecting high-pressure nitrogen into the valve seals and middle sections of the pipeline that is about to be decommissioned as a sealing medium to form a reliable physical isolation barrier. Throughout the switching process, pressure sensors verify the pressure stability of the isolation section in real time to ensure effective sealing.

[0068] After the switch is completed, the system automatically adjusts parameters such as the circulating air ratio to ensure that the temperature and flow rate of the hot inert gas output to the target pipeline are quickly restored and stabilized within the set range. In this embodiment, the set range is 340℃~350℃ and 77000Nm³ / h. The entire switch process is automatic, continuous, and requires no manual intervention, and complete physical isolation is achieved between the two systems.

[0069] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A one-to-two mode intelligent switching method for combined thermal inert gas supply, characterized in that, Includes the following steps: S1, low-calorific-value exhaust gas is premixed with air and then sent to an ultra-insulated combustion device for combustion, ensuring high thermal efficiency and combustion stability, and generating high-temperature flue gas; S2, the high-temperature flue gas is mixed with circulating air to form a thermal inert gas that meets the preset temperature and flow requirements, and then transported to downstream heat-using equipment; S3, through a distribution pipeline equipped with multiple valve groups and isolation structures, the hot inert gas is selectively delivered to two independent hot air pipelines; S4, monitor the operating parameters of the thermal inert gas in real time, and trigger emergency inertization control when the parameters exceed the limit, injecting inert gas that has been cooled into the system; S5 dynamically adjusts operating parameters or performs gas supply switching based on system status and performance indicators.

2. The method for intelligent switching between a one-to-two mode of combined thermal inert gas supply according to claim 1, characterized in that, The control process that ensures high thermal efficiency and combustion stability specifically performs the following operations: It receives real-time component data or calorific value signals of low-calorific-value exhaust gas, as well as flame state signals and flue gas oxygen content data within the combustion device. Through a combustion optimization control model, it calculates the target air-fuel ratio and auxiliary fuel compensation amount, dynamically adjusts the opening of the combustion air flow valve and the exhaust gas premixing proportion valve, and fine-tunes the total fuel supply based on the deviation between the combustion temperature feedback and the set temperature, so that the combustion temperature is stabilized within the set range and the flue gas oxygen content is kept within the optimal range.

3. The one-to-two mode intelligent switching method for combined thermal inert gas supply according to claim 1, characterized in that, Step S3 includes the following sub-steps: S31, receiving hot inert gas from the mixing section; S32, through a distribution pipeline structure including parallel valve groups and isolation mechanisms, the thermal inert gas is distributed to two independent hot air pipelines, wherein the isolation mechanism is configured to inject a sealing medium into the valve seal or the middle section of the pipeline during valve group switching or when the pipeline is not in use, so as to establish a physical isolation anti-cross-flow mechanism. S33, in response to the instructions of the control system, operates the opening and closing state of the valve group to realize the switching of thermal inert gas between the two pipelines; S34, after the switch is completed or during non-gas supply periods, maintain the non-gas supply pipeline in the pressure-holding state of the sealing medium to ensure that the two hot air systems operate independently.

4. The one-to-two mode intelligent switching method for combined thermal inert gas supply according to claim 3, characterized in that, The isolation mechanism injects a sealing medium into the valve seal or the middle section of the pipeline to establish a physical isolation and anti-cross-flow mechanism, specifically by performing the following operations: The system monitors and calculates the real-time pressure difference between the target isolation section and the non-supply section. Based on the pressure difference and the target back pressure setpoint of the sealing medium, an adaptive pressure control algorithm dynamically adjusts the injection flow rate of the sealing medium. A high-precision pressure sensor verifies that the internal pressure of the isolation section is stable within a preset inert atmosphere pressure window, and the sealing medium flow rate is continuously monitored. If the flow rate continuously exceeds the leakage detection threshold, a high-level alarm is triggered and the backup isolation plan is executed. The adaptive pressure control algorithm formula is as follows: ， in, Let t be the injection volume flow rate of the sealing medium. for Pressure control deviation at any time This is the static back pressure setting value. This is the differential pressure compensation coefficient. for Constantly monitor the instantaneous pressure difference between the isolated pipe section and the external pipe section. for Real-time back pressure measurement at the sealing point. , , These are the proportional, integral, and derivative control gains, respectively. , The coefficients of the nonlinear compensation term are... The density of the sealing medium under operating conditions, It is the hyperbolic tangent function.

5. The one-to-two mode intelligent switching method for combined thermal inert gas supply according to claim 4, characterized in that, The proportional control gain, integral control gain, derivative control gain, and nonlinear compensation coefficient in the adaptive pressure control algorithm are dynamic parameters that are self-tuned online based on the real-time operating conditions of the system. The absolute value of the pressure change rate of the target isolation pipe section and the historical fluctuation variance of the flow rate of the sealing medium are acquired in real time as characteristic quantities to characterize the intensity of system disturbance. Based on these characteristic quantities, the control gain and nonlinear compensation coefficient for the next control cycle are calculated and updated in real time through a parameter dynamic mapping model. In high disturbance conditions with drastic pressure changes or increased flow fluctuations, the differential control gain and nonlinear compensation coefficient are automatically increased to enhance the system damping and rapid disturbance rejection capability. At the same time, in low disturbance conditions with stable pressure, the integral control gain is automatically increased to eliminate static errors.

6. The method for intelligent switching between a one-to-two mode of combined thermal inert gas supply according to claim 3, characterized in that, The process of allowing inert gas to flow through a multi-stage pressure reducing device to achieve deep cooling through isenthalpic expansion specifically involves the following operations: Based on the real-time pressure and temperature of the inert gas in the high-pressure storage device, as well as the target injection pressure and desired outlet temperature, the optimal number of depressurization stages and the distribution strategy of intermediate pressure at each stage are calculated online using a gas thermodynamic model. According to this strategy, the opening sequence of the depressurization valves at each stage and the activation status of the interstage cooler are dynamically configured to ensure that the gas approaches the ideal isenthalpic expansion process at each stage. The deviation between the high-response temperature sensor reading at the final stage outlet and the target outlet temperature is fed back to the pre-temperature control logic of the first-stage depressurization valve.

7. The method for intelligent switching between a one-to-two mode of combined thermal inert gas supply according to claim 1, characterized in that, Step S4 includes the following sub-steps: S41, real-time acquisition of temperature, pressure, flow rate and oxygen content parameters of thermal inert gas; S42, determine whether any of the parameters exceeds a preset safety threshold; S43, when the judgment parameter exceeds the limit, inert gas is extracted from the high-pressure storage device; S44, the inert gas is allowed to flow through a multi-stage pressure reducing device, and deep cooling is achieved through isenthalpic expansion, reducing its temperature to a predetermined low temperature range; S45, the cooled inert gas is injected into the hot inert gas pipeline or the mixing section of the combustion device through a targeted injection point.

8. The one-to-two mode intelligent switching method for combined thermal inert gas supply according to claim 7, characterized in that, The process of injecting the cooled inert gas through targeted injection points involves the following steps: A multi-dimensional fault state matrix is ​​constructed, incorporating temperature, flow rate, oxygen content, and flame state signals of the mixing section of the superadiabatic combustion device at key nodes of the thermal inert gas pipeline network. A decision model based on fuzzy logic and real-time thermodynamic simulation is used to diagnose and assess the severity of the current fault mode. Based on this, one or more optimal injection points are dynamically selected from a set of pre-defined physical injection points, including those upstream of the main mixing section, the high-temperature flue gas pipeline, and the hot air main pipeline near the coal mill. According to the gas mixing and heat transfer characteristic model downstream of the selected injection points, the required inert gas distribution flow rate to achieve optimal cooling and inerting effects is calculated. Non-uniform flow distribution is implemented through independent high-speed regulating valves at each injection point, ensuring that the inerting medium extinguishes risk points with the shortest path and highest efficiency within the system, while minimizing disturbance to normal production processes. The decision model formula for optimal injection point selection and flow distribution is as follows: ， ， in, As a comprehensive evaluation indicator, For the quantity of benefit dimensions, For the first Dynamic weights for each benefit dimension For the first A benefit function, It is a sensor signal via state estimation function The obtained system state vector, It is A 3D binary vector represents The enabled status of potential injection points For the cost dimension, For the first Penalty coefficient for each cost dimension For the first A cost function It is a K-dimensional vector representing the traffic allocated to each enabled injection point. , The matrix and vector are used to define linear constraints such as total inert gas supply capacity and maximum flow rate of a single valve.

9. The one-to-two mode intelligent switching method for combined thermal inert gas supply according to claim 7, characterized in that, Based on whether the switching command from the control system or the judgment parameter exceeds the safety threshold, the following operations are performed: A deep learning prediction model integrating time-series data of calorific value, flow rate, and pressure is established to predict the future trends of key parameters of thermal inert gas in advance. During normal system operation, the model runs continuously. If it predicts that a certain parameter will exceed its safety threshold within a future time window, or predicts that the gas supply demand will change significantly, it will generate a pre-switching command in advance to start the pre-cooling of the high-pressure inert gas supply pipeline, or pre-adjust the three-valve group to the standby state, or slightly increase the pressure of the sealing medium in advance.

10. A one-to-two mode intelligent switching system for combined thermal inert gas supply, characterized in that, include: The exhaust gas combustion module is used to premix low-calorific-value exhaust gas with air and then deliver it to the ultra-insulated combustion device for combustion, outputting high-temperature flue gas. The hot air generation and distribution module is used to receive the high-temperature flue gas and circulating air, mix them in the mixing section to generate hot inert gas, and distribute the hot inert gas independently to the two original hot air pipelines through the pipelines equipped with a three-valve group and a nitrogen sealing structure, so as to realize one-to-two intelligent gas supply switching. The emergency inerting module receives high-pressure CO2, reduces and cools the CO2 through a multi-stage pressure reducing device, and outputs low-temperature CO2 gas to the thermal inert gas pipeline or mixing section. The interlocking control module collects system temperature, pressure, flow rate, and oxygen content parameters in real time, and outputs switching commands for the three-valve group or injection commands for the emergency inerting module based on preset logic.

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