A high-efficiency catalytic oxidation system for continuous sulfuric acid production

Abstract

The present invention relates to the technical field of catalytic oxidation for sulfuric acid production, and discloses a high-efficiency catalytic oxidation system for continuous sulfuric acid production, comprising a sentinel catalytic module, a temperature sensing device, and a control unit arranged at the inlet of a main catalytic reactor. By real-time monitoring of the transient thermal response characteristics of the sentinel module, raw gas fluctuation events are determined and micro-feedforward compensation is triggered. The present invention transforms traditional hysteresis feedback into feedforward control based on thermal response characteristics, allowing the catalyst bed to complete state adjustment before the disturbance arrives. At the same time, system self-calibration is achieved through active detection pulses, and the health status of the bed structure is monitored by coupling the propagation time difference of acoustic and thermal waves, thereby improving the system's anti-disturbance capability and long-term stability.

Description

Technical Field

[0001] The invention relates to a high-efficiency catalytic oxidation system for continuous sulfuric acid production, belonging to the technical field of catalytic oxidation in sulfuric acid production. Background Art

[0002] In the field of catalytic oxidation for continuous sulfuric acid production, the mainstream technology relies on temperature feedback from the main catalyst bed to control gas composition and cold shock regulation. This strategy performs well under steady-state conditions, but in real industrial scenarios where the raw gas composition fluctuates, its inherent response delay problem becomes increasingly prominent: the temperature sensor needs to wait for the reaction heat to accumulate before detecting anomalies, and the execution of control instructions and the heat conduction process further aggravate the lag. This double delay causes the catalyst to repeatedly withstand unexpected thermal stress shocks, accelerating the sintering and deactivation of active components, and forcing companies to adopt compromise solutions such as overloading or conservative temperature control.

[0003] Although some studies in recent years have attempted to improve response speed through complex prediction models or adding multi-point sensors, they have generally fallen into new dilemmas: either relying on high-computing edge computing that is difficult to deploy in an engineering manner, or damaging the bed structure due to invasive installation of sensors. More importantly, the existing improvement plans have not been able to break through the underlying logic of post-event remediation and cannot intervene before the disturbance reaches the main bed layer.

[0004] Specifically, existing technologies suffer from the following fundamental limitations: 1. The information acquisition mechanism adheres to thermodynamic equilibrium monitoring, failing to capture transient precursory characteristics of gas disturbances; 2. Control execution relies on high-inertia physical systems, making precise micro-adjustments difficult to achieve; and 3. The system lacks a self-calibration mechanism to mitigate sensitivity degradation during long-term operation. Therefore, the technical challenge addressed by this invention is how to restructure the information flow and control logic within the existing hardware framework to achieve proactive identification and self-correcting micro-compensation of feed gas disturbances. Summary of the Invention

[0005] The present invention provides a high-efficiency catalytic oxidation system for continuous sulfuric acid production, the main purpose of which is to solve the problems of control lag and chronic catalyst damage caused by response delay in existing catalytic oxidation systems.

[0006] To achieve the above object, the present invention provides a high-efficiency catalytic oxidation system for continuous sulfuric acid production, comprising:

[0007] a main catalytic reactor having a main catalyst bed disposed therein;

[0008] a sentinel catalytic module, disposed at the feed gas inlet of the main catalytic reactor or upstream of the main catalyst bed, the sentinel catalytic module having a much lower heat capacity than the main catalyst bed and configured to generate a transient thermal response based on the heat of the catalytic oxidation reaction when the feed gas composition undergoes transient fluctuations;

[0009] a temperature sensing device configured to monitor the temperature of the sentinel catalytic module in real time and output a temperature signal representing a transient thermal response;

[0010] A control unit is electrically connected to a temperature sensing device and a micro-compensation execution device, and the control unit is configured as follows: step a, analyzing the characteristic fingerprint of the transient thermal response based on the time change rate of the temperature signal; step b, when the characteristic fingerprint meets the preset fluctuation judgment condition, it is judged as a raw gas fluctuation event, and the fluctuation judgment condition is that the absolute value of the time change rate of the temperature signal is greater than an empirical threshold determined by system calibration; step c, in response to the judgment, proactively generating and outputting a control instruction to the micro-compensation execution device, and performing a micro-feedforward compensation for the reaction conditions of the main catalyst bed before the raw gas fluctuation reaches the main catalyst bed.

[0011] Preferably, the time rate of change of the temperature signal is the first-order derivative of temperature with respect to time dT / dt, and the control unit is configured to calculate and analyze the characteristic parameters of dT / dt in real time, the characteristic parameters including at least one of its amplitude, peak value, duration or rising rate; and based on the characteristic parameters, compare with the pre-established typical fluctuation type matching rules to determine the type and severity level of the raw gas fluctuation event, thereby generating a control instruction.

[0012] Preferably, the micro-compensation execution device includes one or more small solenoid valves arranged on a cold shock gas pipeline between the main catalyst beds, and the control instructions are used to temporarily adjust the opening time or opening of the small solenoid valve to control the cold shock gas flow through the small solenoid valve, thereby pre-adjusting the gas temperature that is about to reach the main catalyst bed.

[0013] Preferably, the trace compensation execution device includes one or more mass flow controllers arranged on the main inlet pipe of the main catalytic reactor, and the control instructions are used to briefly inject a trace amount of inert gas or dilution air through the mass flow controller to pre-adjust the ratio of oxygen and sulfur dioxide entering the main catalyst bed.

[0014] Preferably, the sentinel catalyst module comprises a standard vanadium catalyst of the same type or similar to the catalyst used in the main catalyst bed, and the catalyst is encapsulated in a high thermal conductivity, low mass metal mesh structure or porous ceramic structure.

[0015] Preferably, the control unit is further configured to: actively send a standardized detection pulse instruction to the micro-compensation execution device during a preset calibration cycle or a period of stable system load, prompting it to produce a small and precisely controllable action; synchronously collect the first transient response generated on the sentinel catalytic module caused by the detection pulse instruction, and the second response generated on the conventional temperature sensor of the main catalyst bed; and based on the degree of deviation of the ratio K between the first transient response and the second response relative to its initial healthy benchmark, dynamically adjust the fluctuation judgment conditions or control instruction parameters used to judge the raw gas fluctuation event, so as to achieve adaptive calibration of the sensitivity of the sentinel catalytic module.

[0016] Preferably, the first transient response is the peak value of the instantaneous change rate of the sentinel catalytic module temperature, and the second response is the fluctuation amplitude of the main catalyst bed temperature; the ratio K is defined as the ratio of the peak value of the first transient response to the fluctuation amplitude of the second response, and the degree of deviation is the percentage change of the ratio K relative to the initial healthy baseline. When the percentage change reaches or exceeds the preset calibration threshold, it is determined that the sensitivity of the sentinel catalytic module has attenuated.

[0017] Preferably, it also includes at least one acoustic sensing device configured to monitor the acoustic signal in the main catalyst bed, the acoustic sensing device is a high-sensitivity piezoelectric vibration sensor installed on the outer shell of the main catalytic reactor or through the shell; and the control unit is further configured to: in response to a gas disturbance event or an actively applied detection disturbance, synchronously collect the acoustic wave pulses and thermal wave pulses excited in the main catalyst bed by the disturbance; based on the arrival time of the acoustic wave pulse determined by the output signal of the acoustic sensing device, and the arrival time of the thermal wave pulse determined by the output signal of the conventional temperature sensor downstream of the main catalyst bed, accurately determine the propagation time difference between the acoustic wave pulse and the thermal wave pulse; and evaluate the physical structure uniformity of the main catalyst bed according to the change law of the propagation time difference.

[0018] Preferably, the control unit is configured to determine that channeling occurs in the main catalyst bed when the propagation time difference decreases relative to the normal value and reaches a preset first threshold value; when the propagation time difference increases relative to the normal value and reaches a preset second threshold value, it is configured to determine that compaction occurs in the main catalyst bed and generate corresponding early warning information.

[0019] Preferably, the control unit is further configured to: automatically switch to an auxiliary control mode based on a preset control curve and a safety margin under non-steady-state conditions such as system startup, shutdown, or large-scale load adjustments; after the non-steady-state condition ends, smoothly switch back to the forward-looking micro-feedforward compensation mode based on the transient thermal response characteristics.

[0020] Compared with the background technology problems, the beneficial effects of the present invention are:

[0021] 1. By capturing the transient thermal response of the feed gas flow through the sentinel catalytic module, the system, for the first time, analyzes fluctuation characteristics before the gas disturbance reaches the main catalyst bed. The temperature change rate (dT / dt), a dynamic characteristic overlooked by traditional control systems, becomes a direct basis for predicting changes in the reaction environment, thereby triggering trace feedforward compensation for cold shock gas or component adjustment. This core mechanism, which converts the threat signal of gas disturbance into pre-adjustment instructions, ensures that the catalyst bed always returns to a stable reaction state before the disturbance arrives, fundamentally avoiding the dual delays of gas transmission and heat conduction in traditional feedback control.

[0022] 2. When the control unit actively drives the micro-actuator to emit standardized detection pulses and synchronously captures the transient temperature response of the sentinel module and the lagged thermal response of the main bed layer, the correlation between the two changes. For example, the peak ratio K becomes the yardstick for system self-test. If the sentinel sensitivity decays, the system automatically adjusts the judgment threshold or compensation parameters based on the initial benchmark without interrupting production or introducing external calibration equipment. This closed-loop calibration logic, which uses the system's own response as a measure, enables the prediction capability to remain accurate during long-term operation, upgrading the static control strategy to a continuously adaptive active system.

[0023] 3. New acoustic sensors capture the acoustic pulses stimulated by actuator disturbances, and the arrival time difference of the thermal waves monitored by downstream temperature sensors together construct a dynamic fingerprint of the bed's physical structure. A uniform bed exhibits a stable time difference, channeling causes time difference compression, and compaction causes time difference extension. Through the temporal correlation of cross-dimensional signals, conventional temperature monitoring nodes are transformed into distributed diagnostic probes. Only by collaborating with acoustic sensors and existing hardware, early structural anomalies that traditionally require gamma scanning or high-voltage drop testing can be identified, providing a leading decision-making basis for catalyst maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a response flow chart of the sentinel drive feedforward compensation under a disturbance event of the present invention.

[0025] Figure 2 This is a diagram showing the evolution of the temperature change rate over time according to the present invention;

[0026] Figure 3 Schematic diagram of the multi-module linkage control framework of the continuous sulfuric acid catalytic oxidation system of the present invention.

[0027] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0028] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The present invention provides an efficient catalytic oxidation system for continuous sulfuric acid production, comprising:

[0030] a main catalytic reactor having a main catalyst bed disposed therein;

[0031] a sentinel catalytic module, disposed at the feed gas inlet of the main catalytic reactor or upstream of the main catalyst bed, the sentinel catalytic module having a much lower heat capacity than the main catalyst bed and configured to generate a transient thermal response based on the heat of the catalytic oxidation reaction when the feed gas composition undergoes transient fluctuations;

[0032] a temperature sensing device configured to monitor the temperature of the sentinel catalytic module in real time and output a temperature signal representing a transient thermal response;

[0033] A control unit is electrically connected to a temperature sensing device and a micro-compensation execution device, and the control unit is configured as follows: step a, analyzing the characteristic fingerprint of the transient thermal response based on the time change rate of the temperature signal; step b, when the characteristic fingerprint meets the preset fluctuation judgment condition, it is judged as a raw gas fluctuation event, and the fluctuation judgment condition is that the absolute value of the time change rate of the temperature signal is greater than an empirical threshold determined by system calibration; step c, in response to the judgment, proactively generating and outputting a control instruction to the micro-compensation execution device, and performing a micro-feedforward compensation for the reaction conditions of the main catalyst bed before the raw gas fluctuation reaches the main catalyst bed.

[0034] Preferably, the time rate of change of the temperature signal is the first-order derivative of temperature with respect to time dT / dt, and the control unit is configured to calculate and analyze the characteristic parameters of dT / dt in real time, the characteristic parameters including at least one of its amplitude, peak value, duration or rising rate; and based on the characteristic parameters, compare with the pre-established typical fluctuation type matching rules to determine the type and severity level of the raw gas fluctuation event, thereby generating a control instruction.

[0035] Preferably, the micro-compensation execution device includes one or more small solenoid valves arranged on a cold shock gas pipeline between the main catalyst beds, and the control instructions are used to temporarily adjust the opening time or opening of the small solenoid valve to control the cold shock gas flow through the small solenoid valve, thereby pre-adjusting the gas temperature that is about to reach the main catalyst bed.

[0036] Preferably, the trace compensation execution device includes one or more mass flow controllers arranged on the main inlet pipe of the main catalytic reactor, and the control instructions are used to briefly inject a trace amount of inert gas or dilution air through the mass flow controller to pre-adjust the ratio of oxygen and sulfur dioxide entering the main catalyst bed.

[0037] Preferably, the sentinel catalyst module comprises a standard vanadium catalyst of the same type or similar to the catalyst used in the main catalyst bed, and the catalyst is encapsulated in a high thermal conductivity, low mass metal mesh structure or porous ceramic structure.

[0038] Preferably, the control unit is further configured to: actively send a standardized detection pulse instruction to the micro-compensation execution device during a preset calibration cycle or a period of stable system load, prompting it to produce a small and precisely controllable action; synchronously collect the first transient response generated on the sentinel catalytic module caused by the detection pulse instruction, and the second response generated on the conventional temperature sensor of the main catalyst bed; and based on the degree of deviation of the ratio K between the first transient response and the second response relative to its initial healthy benchmark, dynamically adjust the fluctuation judgment conditions or control instruction parameters used to judge the raw gas fluctuation event, so as to achieve adaptive calibration of the sensitivity of the sentinel catalytic module.

[0039] Preferably, the first transient response is the peak value of the instantaneous rate of change of the sentinel catalytic module temperature, and the second response is the fluctuation amplitude of the main catalyst bed temperature; the ratio K is defined as the ratio of the peak value of the first transient response to the fluctuation amplitude of the second response, and the degree of deviation is the percentage change of the ratio K relative to the initial healthy baseline. When the percentage change reaches or exceeds the preset calibration threshold, it is determined that the sensitivity of the sentinel catalytic module has attenuated; in practical applications, in order to ensure the comparability between the response parameters and the dimensional consistency of the judgment indicators, this system uses the same measurement unit to collect and process the transient thermal response amplitude of the sentinel module and the temperature fluctuation amplitude corresponding to the main catalyst bed. Both are measured in degrees Celsius to ensure that the ratio is a dimensionless physical quantity, thereby avoiding the problem of bias judgment caused by unit differences. This ratio is an important parameter for the system to evaluate the sensitivity change of the sentinel module. The offset of its fluctuation trend compared with the initial reference baseline is used as the key basis for dynamically adjusting the disturbance identification threshold or compensation strategy. In addition, during the disturbance level identification process, the system control unit introduces a set of temperature change analysis windows with a fixed time span, which are continuously updated on the real-time data sequence in a sliding manner. The characteristic information of the temperature change is extracted within each window period, including key parameters such as the rising speed, change amplitude, duration and fluctuation trend. The control logic matches these characteristic parameters with the preset typical disturbance type feature library, corresponding to the rapid temperature rise, instantaneous fluctuation of gas composition, or the composite disturbance situation of the superposition of the two. The matching result not only determines whether the disturbance has occurred, but also distinguishes the disturbance intensity level, thereby triggering different levels of feedforward compensation response paths to achieve multi-level and targeted adjustment, which are all extended implementation methods known to ordinary technicians in this field.

[0040] Preferably, it also includes at least one acoustic sensing device configured to monitor the acoustic signal in the main catalyst bed, the acoustic sensing device is a high-sensitivity piezoelectric vibration sensor installed on the outer shell of the main catalytic reactor or through the shell; and the control unit is further configured to: in response to a gas disturbance event or an actively applied detection disturbance, synchronously collect the acoustic wave pulses and thermal wave pulses excited in the main catalyst bed by the disturbance; based on the arrival time of the acoustic wave pulse determined by the output signal of the acoustic sensing device, and the arrival time of the thermal wave pulse determined by the output signal of the conventional temperature sensor downstream of the main catalyst bed, accurately determine the propagation time difference between the acoustic wave pulse and the thermal wave pulse; and evaluate the physical structure uniformity of the main catalyst bed according to the change law of the propagation time difference.

[0041] Preferably, the control unit is configured to determine that channeling occurs in the main catalyst bed when the propagation time difference decreases relative to the normal value and reaches a preset first threshold; when the propagation time difference increases relative to the normal value and reaches a preset second threshold, it is determined that compaction occurs in the main catalyst bed and corresponding early warning information is generated; the control unit is further configured to: automatically switch to an auxiliary control mode based on a preset control curve and a safety margin under non-steady-state conditions such as system startup, shutdown or large-scale load adjustment; after the non-steady-state condition ends, smoothly switch back to a forward-looking micro-feedforward compensation mode based on transient thermal response characteristics; wherein, the cold shock gas mainly refers to high-purity nitrogen or inert gas used to quickly reduce the temperature of the raw gas, usually through a dedicated branch transient Injected at the right time; cooling gas is mostly used for temperature regulation in the steady-state stage, and is generally process air with a lower temperature; and dilution gas refers to inert gas or dilution air used to adjust the composition ratio of reaction gas in a short period of time. The three are functionally related, but they are different channels in terms of pipeline setting and control logic. The control unit selects and activates the corresponding path according to the disturbance type to ensure that the compensation measures are targeted; the preset threshold of the propagation time difference is derived from the difference in arrival time of the sound wave and the heat wave recorded in the healthy state of the bed structure during the device debugging phase. After a long period of sampling, the stable fluctuation range is calculated, and then the offset percentage threshold is set. For example, a continuous decrease of more than 15% is set as the basis for channel flow judgment, and a continuous increase of more than 20% is set as the basis for compaction warning. All judgment thresholds can be adjusted and optimized through multi-operation conditions before actual use according to the specific bed thickness, gas thermal conductivity and catalyst filling density. In addition, the parameter judgments involved in temperature response and disturbance identification of this system, such as temperature change rate, sensitivity ratio, etc., have been defined in the built-in logic of the control unit. The temperature change rate is the increase or decrease amplitude of the outlet temperature of the sentinel module per unit time, and the sensitivity ratio is the ratio of the response amplitude of the sentinel module to the corresponding fluctuation amplitude of the main catalyst bed. During the initial setting, dynamic calibration is performed by repeatedly injecting micro-amplitude cold shock pulses or component disturbances to form a unique judgment reference value for the equipment. The control logic makes real-time judgments based on this, as well as the type of fluctuation type in the disturbance event identification mechanism. The matching rules specifically refer to the four parameters of temperature signal change amplitude, change duration, maximum slope and starting mutation time point, which are divided into temperature rise type, component imbalance type and composite type according to preset levels. Each type corresponds to a different compensation path combination. The matching process uses a sliding window method to analyze the temperature change trend in real time, and classifies the response in combination with the disturbance level table. The control curve and limiting strategy are set based on the temperature response curve envelope of the device in multiple stable stages under normal production conditions. When the control unit detects abnormal deviation of the key variable, it will automatically call the corresponding limiting logic to limit the compensation amplitude or response period to avoid misjudgment or excessive response causing secondary disturbance to the bed. These are all extended implementation methods known to ordinary technicians in this field.

[0042] Example 1: In a typical process of continuous sulfuric acid production, the main catalytic reactor is mainly responsible for converting sulfur dioxide ( ) is converted into sulfur trioxide ( ) exothermic reaction, the present invention realizes real-time perception of raw gas disturbance in the early stage by setting a low heat capacity sentinel catalytic module at the raw gas inlet of the reactor. The catalyst used in the sentinel module is consistent with the main bed layer or has equivalent performance, preferably a standard vanadium catalyst, and is encapsulated in a metal mesh or porous ceramic skeleton with good thermal conductivity. The packaging structure significantly reduces thermal inertia, so that the module can react quickly under millisecond-level thermal disturbance conditions and output a clear temperature jump signal. The sentinel module is matched with a set of high-speed temperature detection devices, preferably using armored micro-bead thermocouples or thin-film resistance thermometers (RTD) with a response time of no more than 0.1 seconds. The temperature measuring probe is closely arranged at the outlet of the sentinel module to continuously collect The transient temperature change signal T(t) at the outlet is collected, and the control unit processes T(t) in real time, calculates its first-order derivative and obtains the temperature change rate signal, that is, the rate of change of T with time. In the subsequent sliding window analysis, the system comprehensively judges whether there is a raw gas disturbance event based on the characteristic quantities such as the amplitude, peak value, duration and rising speed of the change rate. When the absolute value of the above-mentioned temperature change rate exceeds the judgment threshold set in the system, the threshold is adaptively determined through multi-condition scanning during the initial debugging stage of the device. The system can identify temperature rise type or component fluctuation type disturbance situations. For temperature rise type disturbance, the micro-injection of cold shock gas will be triggered in advance; for component imbalance type disturbance, the inert dilution strategy will be implemented first for correction. The micro-compensation execution structure in the present invention includes two independent but interrelated adjustment paths. The first path is to set a number of high-speed response solenoid valves on the cold shock gas main pipes between the various stages of the main catalytic bed. The diameter of such solenoid valves is generally not greater than DN6, and the driving current in the normally closed state is less than 0.5 amperes, which can achieve millisecond-level opening and closing actions. The control unit dynamically adjusts the instantaneous cold shock gas flow by adjusting the opening pulse width or on-off duty cycle of the solenoid valve, thereby weakening its thermal shock in advance before the disturbing gas reaches the main catalytic bed; the second path is to set a mass flow controller (MFC) on the main inlet mother pipe of the raw gas, which is used to inject nitrogen or dilution air as needed to adjust the molar ratio of oxygen and sulfur dioxide in a short time. For beds that are sensitive to component disturbances, the oxygen-sulfur ratio can be stabilized within the set target range by setting appropriate injection pulse width and set flow. The above two types of actions are dispatched by the same event queue in the control unit to avoid mutual interference between compensation processes or the risk of over-compensation.

[0043] In order to maintain the high sensitivity of the sentinel module during long-term operation, the system periodically sends detection pulses with fixed amplitude and adjustable duration to the solenoid valve or mass flow controller during the stable operating load phase. By monitoring the ratio of the temperature change rate peak caused by the pulse at the outlet of the sentinel module to the temperature fluctuation amplitude at the outlet of the main catalytic bed, a characteristic quantity for measuring the sensitivity of the sentinel response is established and compared with the benchmark value established at the initial stage of the device operation. When the deviation of the ratio exceeds the preset calibration threshold (for example, 5%), the system automatically determines that the sentinel module has a sensitivity attenuation problem, and then synchronously adjusts the judgment threshold of the temperature change rate or the compensation pulse margin to ensure the stability and reliability of disturbance identification. For the structural integrity monitoring of the main catalytic bed, the present invention introduces an online diagnostic method based on the time difference between the propagation of sound waves and heat waves. The arrival time of the sound wave signal is captured by a piezoelectric vibration sensor attached to the surface of the outer shell, and the response time of the thermal wave peak is obtained by using the downstream thermocouple to calculate the time difference between the two. This time difference is maintained in a relatively stable range when the device is in a healthy operating state. When the difference continuously decreases and reaches the first warning threshold, it indicates the presence of localized channeling. When the difference continuously increases to the second warning threshold, it may reflect catalyst particle compaction or an abnormal increase in bed pressure drop. Upon identifying these abnormal conditions, the system automatically issues an alert to the DCS and records relevant trends for subsequent equipment maintenance or operation and maintenance optimization decisions. Considering that the device is prone to drastic operating fluctuations during startup, shutdown, and large-scale load switching, and that the temperature change rate signal may be subject to noise interference, the control unit of the present invention incorporates a safety control diagram based on an empirical model. Upon identifying signs of unsteady-state operation, such as the frequency of the induced draft fan deviating from the set value by more than a certain percentage, the system automatically switches to this auxiliary mode, activating open-loop limiting control and setting margin protection to prevent over-response in the compensation channel during this period. Once the detection signal returns to a stable state and the temperature change characteristics output by the sentinel module are clearly identifiable, the system returns to the original micro-feedforward compensation logic, achieving smooth and impactless control switching.

[0044] Example 2: In an actual industrial context, for the catalytic oxidation reaction section in the continuous sulfuric acid production process, in order to solve the problems of thermal stress shock and reaction efficiency fluctuation of the main catalyst bed caused by fluctuations in the raw gas composition, the system introduces a feedforward control mechanism based on the collaborative perception of transient thermal response and acoustic heat propagation characteristics. The core of this implementation plan is to construct an active adjustment system with rapid response capability, adaptive sensitivity calibration, and real-time monitoring of the physical state of the bed. The system as a whole consists of four main functional modules: a sentinel catalytic module, a trace compensation channel, a temperature-acoustic sensing unit, and a control decision core. Specifically, a sentinel catalytic module with a compact structure and low heat capacity is set at the main inlet of the raw gas of the main catalytic reactor. The module is filled with a standard vanadium-based catalyst, and the catalyst is encapsulated in a metal woven mesh with high thermal conductivity and low heat capacity, thereby effectively reducing the thermal response inertia of the module. This structure enables the module to quickly generate a thermal response signal with quantitative characteristics when encountering a sudden change in the raw gas composition or temperature. The temperature sensor is arranged at the module outlet. Temperature signals are continuously collected and transmitted to the central control unit. The control unit sets a sliding time window within which the instantaneous rate of change of the temperature signal is analyzed in real time. Parameters include the slope of the temperature change, the amplitude of the fluctuation, the rate of rise, and the duration of the temperature change. When the amplitude of the temperature change rate exceeds a preset threshold (this threshold is set based on the results of multi-condition fluctuation tests during the device commissioning phase and can be dynamically adjusted through the system self-calibration module during operation), it is determined that a feed gas disturbance event has occurred. After the disturbance event is identified, the control unit simultaneously activates two independent compensation channels. First, several cold shock gas injection units are arranged between the main catalytic bed layers. Pulsed cold shock gas is injected through a high-speed response solenoid valve to rapidly reduce the temperature of the gas about to enter the main bed layer. Second, a mass flow controller is installed in the bypass of the main inlet pipeline to briefly introduce a dilution gas, such as nitrogen or air, to achieve a temporary adjustment of the oxygen-sulfur molar ratio. The above two compensation measures are controlled by a unified scheduling algorithm to avoid possible interference or overcompensation between the two.

[0045] To cope with the situation where the sensitivity of the sentinel module may decrease during long-term operation of the system, the control unit regularly sends a set of standardized detection instructions with fixed amplitude and duration to the micro-compensation execution channel during the load stabilization phase, and records the peak temperature change rate caused by it at the outlet of the sentinel module. At the same time, it compares the temperature fluctuation amplitude collected by the temperature sensor downstream of the main catalytic bed and calculates the ratio of the two to form a sensitivity index. When the ratio deviates from the initial state of the system by more than the preset threshold, the control unit will automatically update the disturbance judgment standard or adjust the compensation amplitude, thereby realizing online correction of the performance of the sentinel module; in terms of bed structure health monitoring, the system integrates a set of piezoelectric acoustic wave sensing devices, which are installed at the designated position of the main reactor shell. When the control unit periodically detects or detects a disturbance event, it records the time difference between the sound wave and the heat wave arriving at the outlet of the main bed, and extracts the difference in acoustic and thermal propagation as an evaluation parameter for the uniformity of the bed structure. When the difference shows a trend of shortening or lengthening continuously, it is identified as an early indication of channeling or compaction, and the system will generate corresponding early warning information. Taking into account the signal noise interference that may be generated during the non-steady-state operation stages of the device, such as starting, stopping and drastic load changes, the control unit has a built-in set of control curves and limiting strategies built based on operating experience. When it is detected that key operating parameters (such as induced draft frequency) deviate from the set value and exceed the threshold, the system will automatically switch to the safe control mode and enable the limiting response and delay compensation strategy to suppress the risk of over-adjustment. After the system parameters return to stability, it will automatically return to the feedforward micro-compensation mode to ensure the smoothness and safety of control switching.

[0046] Example 3: In the catalytic oxidation link of continuous sulfuric acid production, the conversion of sulfur dioxide to sulfur trioxide is the core step. The stable operation of the main catalyst bed inside the reactor is crucial to the efficiency and safety of the entire production process. The traditional hysteresis feedback control mechanism often shows a response delay when facing transient fluctuations in the composition or flow of the raw gas, causing the catalyst bed to suffer unnecessary temperature shocks. In the long run, this not only accelerates the deactivation of the catalyst, but may also affect the energy consumption of the system. The present invention proposes an efficient catalytic oxidation system for continuous sulfuric acid production, aiming to address the above challenges; we constructed a test platform that simulates the catalytic oxidation process of continuous sulfuric acid production, and conducted verification tests on the system's dynamic response characteristics, self-calibration function and bed status monitoring.

[0047] The core of this test platform is a miniaturized catalytic oxidation reactor simulator with a main catalyst bed inside. The device can simulate typical catalytic reaction conditions in sulfuric acid production, including temperature, pressure and gas composition. In order to reproduce the disturbance characteristics in actual industrial scenarios, the system is designed with a high-precision gas flow and composition control module, which can introduce transient raw gas flow or composition fluctuations in a controlled manner to simulate disturbance events that may occur in actual production, such as transient changes in the load of upstream process units or short-term switching of raw gas sources. In the experiment, the vanadium catalyst commonly used in industry was selected as the main catalyst. Its activity and selectivity are basically consistent with the performance of the catalyst in the actual production line. The sentinel catalytic module is designed as a low heat capacity structure and adopts the same type of catalyst as the main catalyst bed. A type of vanadium catalyst is encapsulated in a high thermal conductivity, low-mass porous ceramic skeleton to ensure its rapid transient thermal response to temperature and composition changes. The temperature sensing device uses a thin-film resistance thermometer with a response time of no more than 0.1 second. Its temperature measuring probe is closely arranged at the outlet of the sentinel catalytic module to continuously collect transient temperature change signals. The micro-compensation actuator consists of one or more small solenoid valves (the diameter is generally not greater than DN6) arranged on the cold shock gas pipeline inside the simulated reactor and one or more mass flow controllers on the main inlet pipeline to achieve precise control of the cold shock gas flow rate and the dilution gas injection amount. The acoustic sensing device uses a high-sensitivity piezoelectric vibration sensor, which is installed in the simulated reactor shell to monitor the propagation of sound wave pulses.In order to verify the system's ability to quickly feedforward compensate for raw gas fluctuations, we designed a series of typical raw gas fluctuation conditions. In this experiment, for a simulated disturbance event in which the oxygen concentration of the raw gas drops instantaneously from a certain stable value to another lower value, the traditional hysteresis feedback control system usually takes a certain amount of time to detect a significant change in the bed temperature after the disturbance gas reaches the main catalyst bed, and then attempts to recover by adjusting the cold shock gas flow rate. However, the bed temperature fluctuation amplitude is relatively large, and it takes a long time to recover to a stable state, which may cause the catalyst to deviate from the optimal reaction temperature range for a period of time, affecting the conversion efficiency. In comparison, using the test system of the feedforward control of the present invention, the sentinel catalytic module can capture its transient state in a relatively short time after the oxygen concentration drops. The thermal response is specifically manifested in that the first-order derivative (dT / dt) of the sentinel module outlet temperature reaches a peak value within about a few seconds, and its absolute value is greater than the empirical threshold determined by system calibration. Based on this characteristic fingerprint, the control unit quickly identifies the trend of decreasing reaction heat caused by the decrease in oxygen concentration when the feedforward compensation channel is activated, and immediately sends a control instruction to the trace compensation actuator before the disturbing gas reaches the main catalyst bed. Specifically, the control instruction pre-adjusts the gas temperature that is about to reach the main catalyst bed by briefly adjusting the opening time or opening of the cold shock gas solenoid valve. In addition, the control unit can also synchronously instruct the mass flow controller to inject a small amount of inert gas or dilution air in a short period of time to pre-adjust the ratio of oxygen and sulfur dioxide entering the main catalyst bed.

[0048] Through this forward-looking intervention, the temperature fluctuation of the main catalyst bed is effectively suppressed when the disturbance arrives, the maximum fluctuation amplitude can be controlled within a lower range, and it can be restored to the target temperature range in a shorter time. This result shows that the feedforward control mechanism based on thermal response characteristics proposed in the present invention can effectively transform the traditional hysteresis feedback into active prevention, improve the system's anti-interference ability to cope with transient disturbances, and thus reduce the thermal stress shock borne by the catalyst. In order to verify the effectiveness of the system's self-calibration function in maintaining the sensitivity of the sentinel module during long-term operation, we simulated the sensitivity attenuation that may occur in the sentinel module after long-term operation, and observed its self-calibration effect by periodically triggering detection pulses; during the period of stable system load operation, the control unit can actively send a standardized detection pulse instruction to the micro-compensation actuator during the preset calibration cycle or the period of stable system load, prompting it to produce a small and precisely controllable action, and the system synchronously collects the data generated by the micro-compensation actuator. The detection pulse instruction causes the first transient response generated on the sentinel catalytic module, that is, the peak value of the instantaneous change rate of the sentinel module temperature, and the second response generated on the conventional temperature sensor of the main catalyst bed, that is, the fluctuation amplitude of the main catalyst bed temperature. The ratio K is defined as the ratio of the peak value of the first transient response to the fluctuation amplitude of the second response; under the initial healthy baseline state of the system, the ratio K has a certain average value. In the experiment simulating the gradual attenuation of the sensitivity of the sentinel module, we observed that the ratio K may change over time. When the deviation of the ratio K from its initial healthy baseline reaches or exceeds the preset calibration threshold, the system determines that the sensitivity of the sentinel module has attenuated. At this time, the control unit will automatically adjust the fluctuation judgment conditions used to judge the raw gas fluctuation event, for example, adjusting the absolute value of the time change rate of the temperature signal to be greater than an empirical threshold determined by system calibration, or adjusting the parameters of the control instruction to ensure the stability and reliability of disturbance identification.

[0049] This self-calibration mechanism enables the system to dynamically adapt to performance changes of the sentinel module without manual intervention or production interruption, ensuring that it always maintains the ability to accurately identify and proactively compensate for feed gas fluctuations during long-term operation, thereby avoiding the problem of sensitivity attenuation that may occur in the sensor during long-term operation. In order to verify the system's ability to monitor the uniformity of the physical structure of the main catalyst bed, we simulated two typical bed structure anomalies in the test platform: local channeling and compaction; in response to a gas disturbance event or an actively applied detection disturbance, the system synchronously collects the acoustic wave pulses and thermal wave pulses excited by the disturbance in the main catalyst bed, and accurately determines the propagation time between the acoustic wave pulse and the thermal wave pulse based on the output signal of the acoustic sensor device and the arrival time of the thermal wave pulse determined by the output signal of the conventional temperature sensor downstream of the main catalyst bed. difference; under the baseline state of healthy and uniform structure of the main catalyst bed, the propagation time difference remains in a relatively stable range. When simulated local channel flow is introduced into the bed, due to the propagation characteristics of the gas in the low-resistance channel, the propagation time difference may continue to decrease and reach the preset first threshold. At this time, the system determines that channel flow has occurred and generates an early warning message. On the contrary, when a simulated compaction area is introduced into the bed, the resistance of the gas through the compaction area increases, which may cause the arrival time of the heat wave to lag, causing the propagation time difference to increase continuously and reach the preset second threshold. At this time, the system determines that compaction has occurred and generates corresponding early warning information. This diagnostic method based on the time difference of acoustic and thermal wave propagation can evaluate the physical structure uniformity of the main catalyst bed in real time in a non-invasive manner, provide early warning and decision-making basis for catalyst maintenance, and avoid the limitations that may exist in traditional methods.

[0050] Example 4: This example combines Figures 1 to 3 , a high-efficiency catalytic oxidation system for continuous sulfuric acid production is described. Figure 1 As shown in the figure, when the raw gas fluctuation occurs, its disturbance is transmitted to the main bed layer. The sentinel module set at the front end of the system responds quickly, outputs the temperature signal for real-time acquisition, and the control unit extracts its temperature change rate dT / dt. When dT / dt=7.2℃ / s, which meets the disturbance recognition threshold, the system enters the feedforward decision process, performs matching characteristic index analysis, and determines in a loop manner whether the disturbance intensity is greater than the threshold. Once the threshold is triggered, the control unit immediately outputs an 8ms pulse signal to the cold shock valve, which will drive the cold shock gas injection channel for a short time to achieve pre-adjusted airflow. The goal is to suppress the main bed layer temperature rise trend caused by the raw material disturbance and make the final temperature fluctuation <±1.5℃. In this process, the control unit also includes continuous monitoring logic, which is used to dynamically compare the maintenance of the intensity ≤ threshold state after cold shock compensation, forming a complete disturbance response closed-loop mechanism.

[0051] like Figure 2 As shown in the figure, the horizontal axis is time (seconds) and the vertical axis is the temperature change rate (dT / dt). The dashed line in the curve represents the sentinel module and the solid line represents the main bed layer. After the disturbance occurs, the sentinel module can quickly detect the temperature change between about 2 and 3 seconds because its heat capacity is much lower than that of the main bed layer. The peak value of the temperature change rate quickly rises to close to 2.0 and then decreases, indicating that it has a millisecond-level transient thermal response capability to the disturbance; in contrast, the temperature change rate of the main bed layer begins to rise after about 3 seconds, reaches a peak of about 1.5 at about 5 seconds, and then gradually declines. The figure clearly shows that after the disturbance occurs, the sentinel module responds before the main bed layer, and through the feedforward control logic, it realizes the timely triggering of the cold shock gas or component adjustment, effectively weakening the thermal shock borne by the main bed layer.

[0052] like Figure 3 As shown, the left side is the sentinel catalytic module, which has a low heat capacity structure and fast thermal response characteristics. It collects temperature signals through a temperature sensor and calculates dT / dt analysis to realize transient thermal response detection of gas disturbances. The temperature sensor sends data to the control unit, which makes feedforward compensation judgments based on the results of the thermal response analysis and outputs compensation instructions to the micro-actuator. The micro-actuator includes two channels, a cold shock gas valve and a dilution gas valve, which perform micro-adjustment operations, intervene in the main bed reaction conditions in advance, and control the gas temperature or composition. At the same time, the temperature information of the sentinel module is also sent directly to the main catalytic reactor. The main bed contains a vanadium-titanium catalyst bed and has a multi-stage temperature control function. In addition, the system is also equipped with an acoustic sensor for receiving the sound wave signal excited by the main bed and transmitting it to the control unit for time difference analysis to evaluate whether the bed structure has abnormalities such as channeling or compaction.

[0053] Example 5: In the continuous sulfuric acid production process in the metallurgical industry, the composition and flow of the by-product gas often show frequent and irregular disturbances due to fluctuations in upstream processes such as changes in converter speed and adjustment of oxygen enrichment ratio. These disturbances not only directly affect the oxygen content and temperature of the feed gas, but also cause drastic fluctuations in the temperature field and reaction kinetics conditions in the subsequent catalytic oxidation system, thereby affecting Oxidation rate and exhaust gas Concentration stability. This embodiment is based on the above typical scenario and specifically describes how the high-efficiency catalytic oxidation system of the present invention achieves accurate identification and response control of such disturbances through a synergistic thermal response mechanism and a multi-path parameter adaptive control strategy.

[0054] In this embodiment, a raw material disturbance warning module based on gas property monitoring and acoustic wave propagation characteristic analysis is provided at the front end of the catalytic oxidation system. This module utilizes multiple sets of acoustic wave excitation and receiving devices arranged between the intake manifold and the preheating section to capture in real time the sound velocity deviation and propagation mode changes caused by component mutations or temperature anomalies in the raw gas flow, and combines the thermocouple array to perform a preliminary assessment of the raw gas heat content. The system establishes a mapping relationship between acoustic response, heat content fluctuation and reaction precursor temperature through multi-parameter fusion judgment logic to achieve quantitative calibration of the thermal disturbance level. When it is determined that the disturbance level reaches a medium or above threshold, the system automatically enables the feedforward control path to adjust the first-stage catalytic bed inlet distribution and the preheating reflux ratio. The flow adjustment of the preheating gas is based on the gas enthalpy estimation result and the current reactor outlet temperature difference. The target set point is dynamically corrected with the help of the built-in thermal balance algorithm. Specifically, through a set of differential control subunits integrated in the catalytic bed wall temperature monitoring channel, the current actual temperature profile is compared with the standard curve under the historical steady-state conditions, and the introduction ratio of preheating reflux and dilution air is dynamically adjusted to form a rapid thermal buffer response.

[0055] In order to ensure the system's ability to recover and maintain reaction efficiency after disturbance response, in an embodiment, a set of efficiency diagnosis mechanisms based on acoustic-thermal coupling feedback is provided inside the catalytic unit. This mechanism monitors the changes in group velocity and frequency offset of sound waves at different depths in the catalyst bed, and infers the trend of changes in the reaction heat release rate and the local oxidation rate, and then determines whether the current control strategy has met the standards for the reaction efficiency. Under typical operating conditions, when a short-term oxygen enrichment fluctuation occurs suddenly in the upstream smelting process, for example, from 20% to 28%, causing the raw gas temperature to rise sharply by 5 to 10 degrees Celsius, and the SO2 volume fraction fluctuation exceeds 1.5%, the system can complete the identification of the disturbance level within 5 to 10 seconds and trigger the secondary thermal control mode. In this mode, the acoustic array reacquires the reflected echo in a high-frequency excitation manner to calibrate the thermal field distribution model after the disturbance, and assists in adjusting the heat exchanger opening of the exhaust gas cooling section, ultimately achieving the outlet. The concentration fluctuation amplitude is controlled within ±0.3%. It is worth noting that the core of the disturbance identification and response mechanism adopted in this embodiment is to model the coupling relationship between the sound wave propagation characteristics and the heat wave diffusion path. The system uses a preset thermoacoustic model mapping library to pre-generate a family of sound velocity curves under different raw material component combinations and heat content levels, and selects the closest model for rapid fitting and matching during actual operation, thereby avoiding dependence on ideal boundary conditions and improving the model's generalization ability and engineering adaptability.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-efficiency catalytic oxidation system for continuous sulfuric acid production, characterized in that: The system comprises: a main catalytic reactor having a main catalyst bed disposed therein; a sentinel catalytic module, disposed at the feed gas inlet of the main catalytic reactor or upstream of the main catalyst bed, the sentinel catalytic module having a much lower heat capacity than the main catalyst bed and configured to generate a transient thermal response based on the heat of the catalytic oxidation reaction when the feed gas composition undergoes transient fluctuations; a temperature sensing device configured to monitor the temperature of the sentinel catalytic module in real time and output a temperature signal representing a transient thermal response; A control unit is electrically connected to a temperature sensing device and a micro-compensation execution device, and the control unit is configured as follows: step a, analyzing the characteristic fingerprint of the transient thermal response based on the time change rate of the temperature signal; step b, when the characteristic fingerprint meets the preset fluctuation judgment condition, it is judged as a raw gas fluctuation event, and the fluctuation judgment condition is that the absolute value of the time change rate of the temperature signal is greater than an empirical threshold determined by system calibration; step c, in response to the judgment, generating and outputting a control instruction to the micro-compensation execution device, and performing a micro-feedforward compensation for the reaction conditions of the main catalyst bed before the raw gas fluctuation reaches the main catalyst bed.

2. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The time rate of change of the temperature signal is the first-order derivative of temperature with respect to time dT / dt. The control unit is configured to calculate and analyze the characteristic parameters of dT / dt in real time, and the characteristic parameters include at least one of its amplitude, peak value, duration or rising rate; and compare the characteristic parameters with pre-established typical fluctuation type matching rules to determine the type and severity level of the raw gas fluctuation event, thereby generating a control instruction.

3. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The micro-compensation execution device includes one or more small solenoid valves arranged on a cold shock gas pipeline between the main catalyst beds. The control instructions are used to temporarily adjust the opening time or opening of the small solenoid valve to control the cold shock gas flow through the small solenoid valve, thereby pre-adjusting the gas temperature that is about to reach the main catalyst bed.

4. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The trace compensation execution device includes one or more mass flow controllers arranged on the main inlet pipe of the main catalytic reactor. The control instructions are used to briefly inject a trace amount of inert gas or dilution air through the mass flow controller to pre-adjust the ratio of oxygen and sulfur dioxide entering the main catalyst bed.

5. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The Sentinel Catalytic Module consists of a standard vanadium catalyst of the same or similar type as that used in the main catalyst bed, encapsulated in a highly thermally conductive, low-mass metal mesh structure or porous ceramic structure.

6. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The control unit is further configured to: proactively send a standardized detection pulse command to the micro-compensation actuator during a preset calibration period or a period of stable system load, causing it to produce a small and precisely controllable action; synchronously collect a first transient response generated by the detection pulse command on the sentinel catalytic module and a second response generated by a conventional temperature sensor on the main catalyst bed; And based on the degree of deviation of the ratio K between the first transient response and the second response relative to its initial healthy benchmark, the fluctuation determination conditions or control instruction parameters used to determine the raw gas fluctuation event are dynamically adjusted.

7. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 6, characterized in that: The first transient response is the peak value of the instantaneous change rate of the sentinel catalytic module temperature, and the second response is the fluctuation amplitude of the main catalyst bed temperature; the ratio K is defined as the ratio of the peak value of the first transient response to the fluctuation amplitude of the second response, and the degree of deviation is the percentage change of the ratio K relative to the initial healthy baseline. When the percentage change reaches or exceeds the preset calibration threshold, it is determined that the sensitivity of the sentinel catalytic module has attenuated.

8. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: It also includes at least one acoustic sensing device configured to monitor acoustic signals in the main catalyst bed, the acoustic sensing device being a high-sensitivity piezoelectric vibration sensor installed on the outer shell of the main catalytic reactor or passing through the shell; and the control unit being further configured to: in response to a gas disturbance event or an actively applied detection disturbance, synchronously collect the acoustic wave pulses and thermal wave pulses excited in the main catalyst bed by the disturbance; accurately determine the propagation time difference between the acoustic wave pulse and the thermal wave pulse based on the arrival time of the acoustic wave pulse determined by the output signal of the acoustic sensing device and the arrival time of the thermal wave pulse determined by the output signal of the conventional temperature sensor downstream of the main catalyst bed; and evaluate the physical structural uniformity of the main catalyst bed based on the changing law of the propagation time difference.

9. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 8, characterized in that: The control unit is configured to determine that channeling has occurred in the main catalyst bed when the propagation time difference decreases relative to the normal value and reaches a preset first threshold; when the propagation time difference increases relative to the normal value and reaches a preset second threshold, it is configured to determine that compaction has occurred in the main catalyst bed and generate corresponding early warning information.

10. The high-efficiency catalytic oxidation system for continuous sulfuric acid production according to claim 1, characterized in that: The control unit is further configured to automatically switch to an auxiliary control mode based on a preset control curve and safety margin during non-steady-state conditions such as system startup, shutdown, or large-scale load adjustments; and after the non-steady-state condition ends, switch back to the trace feedforward compensation mode based on the transient thermal response characteristics.

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