A method and system for in-situ detection of coke oven gas, and a storage medium

Abstract

The application relates to the technical field of maintenance of tubular heating furnaces in the petroleum industry, and discloses a coke burning gas in-situ detection method, a system and a storage medium. The coke burning gas in-situ detection method comprises the following steps: first, an in-situ sensor is arranged at an opening of an exhaust pipe to collect substance information containing CO, CO2, oxygen and particle data; after filtering processing, the temporary CO and CO2 data are matched with preset rising characteristics to determine a coke burning start time; then, the temporary CO, CO2 and particle data are combined to calculate coke burning carbon data, and the particle data are used to calculate the particle concentration according to the volume of a furnace tube; when the particle concentration is lower than a reference concentration, a stop warning is given; when the coke burning carbon data are smaller than first reference data, a stop is prompted and a time is recorded; and finally, the latest coke burning time is calculated. The method realizes in-situ real-time monitoring of coke burning gas components and accurate control of the coke burning process, effectively avoids damage to the furnace tube and energy waste, and guarantees safe and efficient operation of the coke burning operation of the tubular heating furnace.

Description

Technical Field

[0001] This application relates to the technical field of maintenance of tubular heating furnaces in the petroleum industry, and in particular to an in-situ detection method, system and storage medium for coking gas. Background Technology

[0002] In the petrochemical industry, ethylene cracking tubular heaters are core equipment in crude oil processing, with their furnace tubes operating under high temperature and pressure for extended periods. During the cracking process of crude oil within the furnace tubes, coke deposits inevitably form. Over time, this coke gradually clogs the furnace tube channels. When the furnace tube temperature reaches 1115℃, if coke is not promptly removed, the coke layer will further exacerbate the thermal resistance of the furnace tubes, leading to a significant decrease in heat transfer efficiency and increased energy consumption. More seriously, localized overheating can cause furnace tube bulging, cracking, or even bursting, resulting not only in production interruptions but also significant safety hazards such as high-temperature material leaks, fires, and explosions. Therefore, regularly removing coke from the furnace tubes is a necessary measure to ensure the safe and stable operation of tubular heaters.

[0003] During the coking process in the furnace tubes, coke undergoes an oxidation reaction with the introduced air or steam, generating coking gas containing components such as CO, CO2, O2, and hydrocarbons. The composition ratio of these gases changes dynamically with the coking process. Real-time and accurate monitoring of the coking gas composition can indirectly reflect the combustion state and residual amount of coke within the furnace tubes, thereby determining the progress of the coking operation. For example, in the early stages of coking, the coke content is high, and the concentration of CO generated by combustion will gradually increase; as coking progresses, the coke gradually decreases, the proportion of CO2 concentration will gradually increase, while the O2 concentration will decrease due to consumption. Through continuous analysis of the coking gas composition, operators can adjust the coking process parameters in a timely manner to ensure a uniform and thorough coking process, avoiding damage to the furnace tubes from over-coking or potential hazards from incomplete coking.

[0004] Currently, domestic oil refineries commonly use a method of collecting coke gas from the furnace via sampling tubes and then transporting it to a laboratory or analytical control room located far from the furnace for analysis using large analyzers. This traditional offline analysis method has significant drawbacks: a long time delay exists between gas collection and obtaining analytical results, making it impossible to reflect the current coking state within the furnace in real time. This makes it difficult for operators to make timely adjustments, potentially leading to excessively long or short coking times, increasing the risk of furnace tube damage and energy waste. Therefore, there is an urgent need for a technical solution that can detect and analyze coke gas components in situ at the coking site in real time to overcome the shortcomings of existing external sampling and analysis methods. Summary of the Invention

[0005] In order to obtain more accurate analysis data in real time and make timely adjustments to the furnace tube control strategy, this application provides an in-situ detection method, system and storage medium for coke gas.

[0006] In a first aspect, this application provides an in-situ detection method for coke gas, employing the following technical solution:

[0007] An in-situ detection method for coke gas includes the following steps:

[0008] In-situ sensors are installed at multiple openings on the exhaust pipe of the coking gas. The in-situ sensors are used to analyze the substance content of the coking gas and generate substance data.

[0009] Based on the scorching command, scorching is performed according to the preset scorching time;

[0010] Acquire the substance data generated by the in-situ sensor, the substance data including CO data, CO2 data, oxygen data and particulate data;

[0011] The material data is filtered to obtain temporary data, which includes temporary CO data, temporary CO2 data, temporary oxygen data, and temporary particle data.

[0012] If a preset data rise characteristic is found when the temporary CO data and the temporary CO2 data are matched, the charring start time is recorded.

[0013] The coke data is calculated based on the temporary CO data, temporary CO2 data, and temporary particulate data.

[0014] The particulate matter concentration is calculated based on the temporary particle data and the furnace tube volume. When the particulate matter concentration is less than the preset reference concentration, a stop coking warning is issued.

[0015] If the coke burning data is less than the preset first reference data, a prompt to stop burning will be issued, and the burning stop time will be recorded.

[0016] The latest charring time is calculated based on the charring start time and the charring stop time.

[0017] By adopting the above technical solution and installing in-situ sensors at multiple openings in the coking gas exhaust pipe, real-time data on CO, CO2, oxygen, and particulate matter in the coking gas can be collected. This avoids the time delay problem caused by long-distance sampling and transmission in traditional offline analysis, ensuring that the acquired data is highly synchronized with the current coking state in the furnace. The collected data is filtered to effectively eliminate noise interference, ensuring the accuracy and reliability of the data. When judging the coking process, the system automatically matches the preset data rise characteristics based on the processed temporary CO and CO2 data to accurately identify the coking start time, changing the previous reliance on manual subjective judgment. At the same time, the system calculates the coke data by combining the temporary CO, CO2, and particulate data, and calculates the particulate matter concentration by using the particulate data and the furnace tube volume. When the particulate matter concentration is lower than the preset reference concentration, the system issues a coking stop warning, indicating that coking is nearing its end; if the coke data is lower than the preset first reference data, the system issues a coking stop warning and records the stop time to avoid over-coking damaging the furnace tube or incomplete coking leaving hidden dangers. Finally, based on the recorded start and stop times of coking, the latest coking time is accurately calculated, providing a reliable basis for subsequent process parameter adjustments.

[0018] Optionally, the method further includes the following steps:

[0019] Based on the scorching command, scorching is performed according to the latest scorching time;

[0020] The O2 content or O2 delivery speed during coking is adjusted in a positive correlation with the latest coking time; the longer the latest coking time, the faster the O2 content or O2 delivery speed during coking; the shorter the latest coking time, the slower the O2 content or O2 delivery speed during coking.

[0021] By adopting the above technical solution, based on the accurately calculated latest coking time, the system can adjust the O2 content or conveying speed according to the actual coking time under different operating conditions. When the latest coking time is long, it indicates that there is more coke residue in the furnace tube or the combustion efficiency is low. At this time, the system can quickly increase the O2 content or conveying speed to enhance the oxidation reaction intensity, accelerate the coke combustion rate, and shorten the overall coking time. Conversely, if the latest coking time is short, it indicates that the coke is consumed quickly. The system can reduce the O2 content or conveying speed to avoid excessive local temperature in the furnace tube due to excessive O2, thus achieving dynamic and precise control of the coking process and reducing the lag and subjectivity of manual intervention. Through the positive correlation adjustment between O2 content or conveying speed and coking time, it can ensure that oxygen resources are used efficiently under different coking requirements. This avoids slow coking and prolonged operation time due to insufficient O2 supply, or energy waste and unnecessary high-temperature losses due to excessive O2 supply.

[0022] Optionally, the method further includes the following steps:

[0023] Based on the CO data and the CO2 data, CO and CO2 concentration curves were obtained, respectively.

[0024] Integrating the CO and CO2 concentration curves yields the areas under the CO and CO2 curves, respectively.

[0025] Based on the area of ​​the CO curve, the total area of ​​the CO2 curve, and the volume of the furnace tube, the cumulative mass of coke burned is calculated using the coke combustion reaction formula.

[0026] By adopting the above technical solution, the coke combustion reaction formulas are (C + O2 → CO2, 2C + O2 → 2CO). The CO and CO2 concentration curves reflect the dynamic changes of these two gas concentrations over time during coking. The area under the curve obtained by integrating these curves comprehensively reflects the total amount of CO and CO2 generated throughout the entire coking process. Combining this with the furnace tube volume parameter, since the coking gases are generated and distributed within this specific volume space, the amount of gas represented by the curve area is converted into the amount of coke participating in the reaction based on the stoichiometric relationship using the two coke combustion reaction formulas mentioned above, thus calculating the cumulative coke mass burned. This allows for real-time and accurate calculation of the cumulative coke mass burned. Operators can intuitively understand the coke consumption within the furnace tube through this quantitative indicator, thereby clearly determining the stage of the coking operation. This eliminates the previous reliance on experience or vague indicators to judge the coking progress, providing strong support for the refined management of coking operations.

[0027] Optionally, the step of filtering the material data further includes the following sub-steps.

[0028] The material data is filtered by moving average using a sliding window.

[0029] Specifically, the width of the sliding window is adjusted inversely according to the rate of change of the mass of the burned coke; the faster the rate of change of the mass of the burned coke, the narrower the width of the sliding window; the slower the rate of change of the mass of the burned coke, the wider the width of the sliding window.

[0030] By adopting the above technical solution and using moving average filtering, material data can be effectively smoothed, random noise removed, and data stability and reliability improved. Adjusting the sliding window width based on the inverse correlation of the rate of change in coke mass allows the filtering to better reflect actual working conditions. When the rate of change in coke mass is rapid, narrowing the sliding window width allows for more timely capture of rapid data changes, preventing over-smoothing and the obscuring of crucial information. When the rate of change is slow, widening the window width further eliminates low-frequency noise, resulting in smoother data and ensuring data processing quality.

[0031] Optionally, the method further includes the following steps:

[0032] Calculate the rate of change of CO concentration and the rate of change of CO2 concentration; when the rate of change of CO concentration or the rate of change of CO2 concentration exceeds the corresponding threshold, issue the first warning.

[0033] Calculate the O2 consumption rate, and issue a second warning when the O2 consumption rate exceeds the set consumption threshold.

[0034] Calculate the attenuation coefficient of particulate matter concentration; when the attenuation coefficient of particulate matter concentration exceeds the set attenuation threshold, issue a third early warning.

[0035] By adopting the above technical solutions, abnormalities in the coking process can be detected in real time, such as runaway reaction, oxygen consumption, and particulate matter decay, providing rapid early warning and assisting in process adjustments, thus shortening the abnormality handling cycle.

[0036] Optionally, the method further includes the following steps:

[0037] When the CO concentration is greater than 1000 ppm and the rate of change of CO concentration is greater than 50 ppm / s, the intense combustion of coke is determined to have begun, which is defined as the initial stage of coking.

[0038] When the CO2 concentration is greater than 30% and the hydrocarbon concentration is less than 1000 ppm, the stable coking period begins, which is defined as the main reaction stage.

[0039] When the CO concentration is <500ppm, the O2 concentration is >18%, and the rate of change is <10ppm / s for 10 consecutive minutes, the pre-judgment of the end of the reaction is triggered and defined as the end of the reaction period.

[0040] By adopting the above technical solution and setting multi-parameter combination thresholds, the initial stage of coking, the main reaction, and the final stage of the reaction can be accurately divided, enabling real-time and accurate judgment of the coking process status. Determining the initial stage of coking helps operators promptly grasp the starting point of intense coke combustion and quickly adjust process parameters; defining the stable coking period provides a clear reference for continuous and efficient coking operations, ensuring stable process operation; and the triggering conditions for the final stage of the reaction avoid the problems of over- or under-coking, preventing furnace tube damage and ensuring complete coke combustion, significantly improving the safety, efficiency, and accuracy of coking operations.

[0041] Optionally, the method further includes the following steps:

[0042] If the rate of change in CO concentration is detected to be greater than the corresponding set threshold, and the CO concentration is greater than 2000 ppm, or the particulate matter concentration is greater than the corresponding set threshold, the supply of oxidation medium will be cut off.

[0043] By adopting the above technical solution and setting strict thresholds for CO concentration and its rate of change, as well as particulate matter concentration, a robust safety protection mechanism has been established. When the CO concentration rises sharply and exceeds the standard, or the particulate matter concentration is abnormally high, cutting off the supply of the oxidation medium can quickly curb potentially uncontrolled and violent reactions within the furnace tube, preventing major accidents such as furnace tube rupture, high-temperature material leakage, and fires and explosions caused by extreme conditions such as local overheating and deflagration. This maximizes the protection of equipment safety and personnel safety, while also reducing production interruption losses and environmental pollution risks caused by accidents.

[0044] Secondly, this application provides an in-situ detection system for coking gas, employing the following technical solution:

[0045] An in-situ detection system for coke gas includes a processor, wherein the processor performs the steps of the in-situ detection method for coke gas as described in any of the preceding claims.

[0046] Thirdly, this application provides a storage medium, which adopts the following technical solution:

[0047] A storage medium storing a program that, when executed by a processor, implements the steps of the in-situ detection method for coke gas described in any one of the preceding claims.

[0048] In summary, this application includes at least one of the following beneficial technical effects: Real-time data collection of substances including CO and CO2 is achieved through an in-situ sensor at the exhaust pipe opening. After filtering, the start and end times of coking are determined based on data characteristics, and coke data and particulate matter concentration are calculated to precisely control the coking process. Simultaneously, the O2 content or conveying speed is dynamically adjusted based on the latest coking time, and the cumulative coke mass is calculated based on the CO / CO2 curve integral. Data processing is optimized through adaptive adjustment of the sliding window width. Furthermore, multi-parameter early warning systems are set, and even an emergency shutdown mechanism can be implemented. Coking stages are defined, allowing for real-time anomaly detection, precise process segmentation, and prevention of safety accidents. This method achieves precise monitoring and intelligent control of the entire coking process, effectively improving coking efficiency, ensuring equipment safety, and reducing energy consumption and accident risks. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the steps of an in-situ detection method for coke gas.

[0050] Figure 2 This is a flowchart showing the steps for adjusting the O2 content or O2 delivery speed during coking based on the latest coking time.

[0051] Figure 3 This is a flowchart illustrating the steps involved in calculating the cumulative mass of burned coke. Detailed Implementation

[0052] The embodiments of this application are described in detail below, and examples of the embodiments are shown in the accompanying drawings.

[0053] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] This application discloses an in-situ detection method for coking gas, referring to... Figure 1 It includes the following steps:

[0055] In-situ sensors based on tunable diode laser absorption spectroscopy (TDLAS) are installed at multiple openings in the coke gas exhaust pipe, along with a charge-based dust detection device. Among these:

[0056] TDLAS sensor: Targeting the characteristics of ethylene coking gas, it prioritizes the detection of CO2 (range 0-50000ppm), CO (0-10000ppm), and O2 (0-20.9vol%). By emitting lasers of specific wavelengths (e.g., 2.0μm band for CO2), it captures the absorption signal of gas molecules to the laser in real time and directly generates the concentration data of each gas component.

[0057] Charge-based dust sensor: Composed of a power-free probe, transmitter and flange, it uses the principle of electrostatic induction to monitor dust concentration in real time (range 0-20000mg / m³). It features false alarm prevention, low maintenance and high temperature resistance (suitable for high temperature furnace environment), avoiding the errors caused by moisture or conductive particles in traditional dust detection.

[0058] By using a distributed deployment with multiple openings, the collected material data is ensured to cover different areas inside the exhaust pipe, avoiding single-point sampling bias and enabling full-section monitoring of the spatial dimensions of the coking gas composition.

[0059] Upon receiving the coking command, the system initiates the process of introducing an oxidizing medium (such as air) according to the preset coking time, and simultaneously triggers the in-situ sensor to enter the real-time data acquisition mode.

[0060] The raw material data (CO, CO2, O2, dust, H2O) are processed using a moving average filtering algorithm, and the noise reduction effect is optimized by dynamically adjusting the width of the moving window.

[0061] When the quality of burning coke changes rapidly (such as in the initial stage of coking), the window width is automatically narrowed (e.g., 1-5 seconds) to preserve the details of high-frequency changes.

[0062] As combustion slows down, the window width widens (e.g., 10-30 seconds) to enhance low-frequency noise suppression.

[0063] After filtering, temporary CO data, temporary CO2 data, temporary oxygen data, and temporary particulate data are generated.

[0064] The system analyzes the temporary CO and CO2 concentration curves in real time. When it detects that both concentrations show a step increase (such as CO jumping from the baseline to over 100 ppm with a slope > 50 ppm / s, and CO2 increasing significantly from near 0), it determines that this is the starting point of intense coke combustion and automatically records it as the start time of coking, replacing the lag of manual observation.

[0065] By combining temporary CO, CO2 concentration and particulate data, and based on the coke combustion reaction formula (C+O2→CO2, 2C+O2→2CO), the degree of coke combustion is quantified by stoichiometric conversion between the integral area of ​​the concentration curve (reflecting the cumulative amount of gas generated) and the furnace tube volume.

[0066] Using temporary particle data and furnace tube volume, the dust content per unit volume is calculated in real time. mg / m 3) When the concentration is lower than the preset reference concentration (e.g., 500 mg / m³), a stop coking warning is triggered, prompting the operator that the coke combustion is nearing its end.

[0067] If the coke burning data is less than the first reference data (such as the preset minimum effective combustion amount), it is determined that the coke burning is insufficient, and the system will forcibly prompt to stop the coke burning and record the stop time;

[0068] If the normal termination conditions are met (such as particulate matter concentration meeting the standard and coke burning data being qualified), the latest coke burning time is calculated based on the start and stop times to provide closed-loop feedback for subsequent processes.

[0069] TDLAS technology has a response time of less than 2 seconds, eliminating the minute-level delay of traditional offline analysis, and achieving a data synchronization rate of more than 99% with furnace operating conditions.

[0070] The charge-based dust detection method has a resolution of 0.01 pA and is suitable for high-temperature (≤1000℃), high-pressure, and highly corrosive environments, ensuring data reliability under complex working conditions.

[0071] Through multi-parameter linkage analysis (such as CO / CO2 concentration change rate, O2 consumption rate, dust attenuation coefficient), the coking stage is automatically divided (initial stage, main reaction stage, and final reaction stage), and corresponding warnings are triggered (such as the emergency shutdown mechanism can be activated when CO > 2000ppm and change rate > 50ppm / s).

[0072] It supports seamless integration with DCS systems and dynamically adjusts the O2 delivery speed based on the latest coking time (the longer the time, the faster the O2 flow rate), optimizing oxidation reaction efficiency and reducing energy consumption.

[0073] In-situ installation eliminates the need for long-distance sampling, reducing the risk of human contact with high-temperature gases; TDLAS devices have no moving parts and are maintenance-free, reducing annual maintenance costs, and support self-calibration, so it is recommended to calibrate once a year to ensure long-term operational stability.

[0074] Reference Figure 2 Once the system completes the previous coking operation and calculates the latest coking time, this time data will serve as one of the core parameters for the next coking command. The specific process is as follows:

[0075] When the operator issues the coking command, the system automatically retrieves the latest historical coking time and, in conjunction with the current furnace tube operating conditions, such as the amount of coking residue from the previous coking and the type of crude oil, generates an initial O2 supply strategy.

[0076] During the coking process, in-situ sensors continuously monitor CO, CO2 concentrations, and particulate matter data. The system synchronously calculates the real-time coking progress deviation (the difference between the current time and the latest coking time) and dynamically adjusts the O2 parameter based on the deviation.

[0077] Establish a linear positive correlation model between the O2 delivery speed VO2 and the latest coking time T1, i.e., VO2 = k × T1 + b (where k is the proportionality coefficient and b is the reference flow rate). For example:

[0078] If T1 = 120 minutes (long-term burning), VO2 will automatically increase to 1.5 times the baseline value;

[0079] If T1 = 60 minutes (short-term scorching), VO2 is maintained at 80% of the baseline value.

[0080] The O2 content (volume percentage) is adjusted in conjunction with the delivery speed. For example, in high-flow-rate scenarios, the O2 concentration is increased from 21% (air) to 25% (oxygen-enriched air) to further enhance the oxidation reaction efficiency.

[0081] Long-term coking scenario: When the latest coking time T1 > TH (e.g., the preset threshold is 90 minutes), it is determined as "severe coke deposition", and the system performs the following operations:

[0082] The oxygen-enriched supply mode is activated, increasing the O2 content to 25%-30%.

[0083] The conveying speed is increased to the maximum design value (e.g., 1000 m³ / h), and pulse oxygen supply is activated (intermittent high-velocity impact to enhance the penetration of the coke layer).

[0084] Short-term charring scenario: When T1 < TL (e.g., the preset threshold is 45 minutes), it is determined as "low char residue", and the system performs the following operations:

[0085] Switch to air supply mode, O2 level maintained at 21%;

[0086] The conveying speed is reduced to 50%-70% of the baseline value (e.g., 300-500 m³ / h) to avoid excessive oxidation that could cause a sudden rise in furnace tube temperature.

[0087] The synergistic effect of high O2 concentration and flow rate accelerates the oxidation reaction rate of coke (increased C+O2→CO2 reaction rate), especially suitable for severe conditions with coke thickness >5mm, and can shorten the overall coking time. High-speed airflow (e.g., >5m / s) can effectively scour the inner wall of the furnace tube, reduce the diffusion resistance of the coke layer to O2, and avoid secondary coking problems caused by "complete surface combustion and deep coke residue". Compared with the traditional constant oxygen supply mode, dynamic adjustment can improve the effective utilization rate of O2. It avoids furnace temperature exceeding the limit due to excessive oxygen supply (e.g., dropping from 1100℃ to below 950℃), reduces fuel consumption, and reduces heat loss of equipment. Through precise matching of O2 flow rate and concentration, local overheating is suppressed (temperature difference fluctuation reduced from ±50℃ to ±15℃), extending the service life of furnace tubes (fatigue crack initiation cycle extended by 2-3 times). In low O2 demand scenarios, reducing the erosion of furnace tube materials (such as Cr5Mo steel) by oxidizing atmosphere reduces the risk of intergranular corrosion and oxide scale shedding, thus lowering the average annual maintenance cost.

[0088] Reference Figure 3 The method also includes the following steps:

[0089] Real-time CO (0-10000ppm) and CO2 (0-50000ppm) concentration data acquired using TDLAS technology are plotted with time on the horizontal axis (resolution ≤1 second) and concentration on the vertical axis to generate dynamic change curves. For example:

[0090] In the initial stage of coking: the CO curve shows a rapid upward trend (slope > 50ppm / s), while the CO2 curve starts with a lag, reflecting that incomplete combustion of coke is the dominant factor;

[0091] Main reaction stage: The CO curve reaches its peak and then declines, while the CO2 curve continues to rise (accounting for >30%), corresponding to the stable period dominated by complete combustion;

[0092] At the end of the reaction: the CO curve drops below 500 ppm and the CO2 curve flattens out, indicating that the coke is close to being completely burned.

[0093] The concentration curves were summed using the trapezoidal integral method. The summation result represents the cumulative total gas concentration per unit time, reflecting the total amount of CO and CO2 generated during the coking process.

[0094] According to the coke combustion reaction formula:

[0095] Complete combustion: C + O2 → CO2, 1 mol of carbon produces 1 mol of CO2;

[0096] Incomplete combustion: 2C + O₂ → 2CO, 2 mol of carbon produces 2 mol of CO. Let the areas under the curves for CO and CO₂ be ACO and ACO₂ (units: ppm·s), respectively, and the furnace tube volume be V (unit: m³), ​​then:

[0097] The amount of CO: nCO = ACO × V × 10 -6 / (R×T) (R is the gas constant, T is the absolute temperature);

[0098] The amount of CO2: nCO2 = ACO2 × V × 10 -6 / (R×T). According to the law of conservation of carbon, the cumulative mass of coke burned, mC, is: mC = (nCO + nCO2) × MC; where MC = 12 g / mol is the molar mass of carbon.

[0099] The furnace temperature (accuracy ±1℃) is monitored synchronously by TDLAS to correct the impact of gas volume expansion on the calculation of the amount of substance. Data from the furnace tube pressure sensor (accuracy ±0.1kPa) is input, and pressure correction is performed using the ideal gas law to ensure that the calculation results are not affected by fluctuations in operating conditions.

[0100] The filtering process for material data also includes the following sub-steps:

[0101] Moving average filtering suppresses the influence of random noise by taking the arithmetic mean of historical data within a time window. In coking gas detection, this algorithm has a significant noise reduction effect on high-frequency fluctuating data such as CO and CO2 concentrations (e.g., sampling frequency of 10Hz).

[0102] The system's default window width is 10 seconds, suitable for balanced filtering needs in most operating conditions. For example, during the main combustion reaction stage (combustion stability), a 10-second window can effectively smooth out small concentration fluctuations caused by airflow fluctuations while preserving trend-based changes.

[0103] The rate of change of coke mass is quantified by dmC / dt (unit: g / s) and is output in real time by the cumulative coke mass calculation module.

[0104] Regulation rules:

[0105] When dmC / dt > Vhigh (e.g., a preset threshold of 10g / s), it is determined to be the "rapid burning period", and the window width is automatically narrowed to 2-5 seconds;

[0106] When Vlow≤dmC / dt≤Vhigh (e.g., 1-10g / s), maintain the default window width for 10 seconds;

[0107] When dmC / dt < Vlow (e.g., <1g / s), it is determined to be a "slow burning period", and the window width is widened to 20-30 seconds.

[0108] The system collects dmC / dt data every second and compares it with the threshold; it dynamically updates the filter window parameters through the digital signal processing (DSP) module, adjusting the delay to <100ms to ensure synchronous changes with the combustion state; it sets the extreme values ​​of the window width (minimum 2 seconds, maximum 30 seconds) to avoid filter failure due to abnormal parameters.

[0109] The method also includes the following steps:

[0110] Calculate the rate of change of CO and CO2 concentrations; when the rate of change of either CO or CO2 concentration exceeds the corresponding threshold, a first warning is issued. The change in CO / CO2 concentration per unit time reflects the intensity of the coke combustion reaction. CO change rate threshold: 50 ppm / s during the rapid combustion period and 20 ppm / s during the stable period (dynamically adjusted); CO2 change rate threshold: uniformly set at 30 ppm / s (reflecting the upper limit of complete combustion intensity).

[0111] The O2 consumption rate is calculated, which is the decrease in O2 concentration per unit time, reflecting the intensity of oxygen participation in the oxidation reaction. A second warning is issued when the O2 consumption rate exceeds a set threshold. Threshold settings: Normal operating conditions: 0.5 vol% / s (corresponding to normal combustion intensity); Oxygen-enriched operating conditions: 1.0 vol% / s (to prevent excessive oxygen supply from causing temperature runaway).

[0112] The decay coefficient of particulate matter concentration is calculated. This coefficient represents the relative rate of change in particulate matter concentration between adjacent time points, reflecting the efficiency of coke combustion product (dust) removal and combustion uniformity. A third warning is issued when the particulate matter concentration decay coefficient exceeds a set decay threshold. Warning threshold: 0.3 / s (When dust concentration decreases by more than 30% per minute, it indicates abnormal combustion or pipe blockage).

[0113] It can detect abnormalities in the coking process in real time, such as runaway reaction, oxygen consumption and particulate matter decay, provide early warning and assist in process adjustment, and shorten the abnormal handling cycle.

[0114] The method also includes the following steps:

[0115] Initial stage of coking: CO concentration > 1000 ppm: indicates that the coke has begun to decompose violently, producing a large amount of incomplete combustion products; CO concentration change rate > 50 ppm / s: reflects a sharp increase in the combustion reaction rate, requiring immediate intervention and control. Characteristics of this stage: the coke layer on the inner wall of the furnace tube rapidly heats up to 600-800℃, with competition between thermal decomposition and oxidation reactions; the concentration of hydrocarbons in the flue gas is high (>1000 ppm), posing a risk of deflagration. At this time, it is necessary to start oxygen-enriched gradient oxygen supply (O2 concentration gradually increased from 21% to 25%) to avoid a sudden rise in CO caused by local oxygen deficiency; using the furnace temperature field scanning function (with infrared thermal imager running simultaneously), high-temperature hot spots are located and burner power is adjusted.

[0116] Main reaction stage: CO2 concentration > 30%: indicates that the combustion reaction is mainly complete oxidation (C + O2 → CO2), with stable heat release; hydrocarbon concentration < 1000 ppm: indicates that the cracking reaction is basically complete and has entered the pure oxidation stage. Characteristics of this stage: the combustion rate tends to stabilize, and the CO concentration gradually decreases from its peak to 500-1000 ppm; particulate matter concentration reaches its peak (2000-5000 mg / m³), reflecting uniform detachment of the coke layer. At this time, maintain a constant O2 flow rate (e.g., 800 m³ / h) to ensure continuous and efficient oxidation reaction; initiate dynamic dust balance control (e.g., adjusting the induced draft fan frequency) to avoid pipe blockage.

[0117] Final stage of the reaction: CO concentration < 500 ppm: Remaining coke has been largely burned, and incomplete combustion products have significantly decreased; O2 concentration > 18%: Oxygen consumption is nearly stopped, and the furnace enters an oxygen-rich state; Continuous 10-minute change rate < 10 ppm / s: All parameters tend to stabilize, confirming that the combustion reaction is nearing termination. Characteristics of this stage: Furnace tube temperature drops below 400℃, reducing the risk of thermal stress; Particulate matter concentration < 500 mg / m³, meeting environmental emission requirements. At this time, a stepped cooling program is implemented (furnace temperature reduced by 50℃ every 10 minutes) to prevent furnace tube cracking due to thermal expansion and contraction; switch to nitrogen purging mode (flow rate 500 m³ / h) to replace residual combustible gases and prepare for shutdown maintenance.

[0118] In addition, an emergency stop trigger mechanism can be provided:

[0119] Scenario 1: Both CO concentration and rate of change exceed limits

[0120] When the CO concentration is greater than 2000 ppm and the rate of change is greater than the set threshold (e.g., 80 ppm / s during the rapid combustion period and 50 ppm / s during the stable period), it is judged as a dual risk of "combustion runaway + accumulation of combustible gas".

[0121] CO concentration > 2000 ppm: This exceeds the occupational exposure limit (PC-TWA 20 ppm, GBZ 2.1-2007) by 100 times and is close to the lower explosive limit (12.5%, i.e. 125000 ppm) by 1.6%, thus forming a flammable environment.

[0122] Excessive rate of change: This reflects the violent decomposition of coke or insufficient local oxygen supply, leading to a rapid surge in CO in a short period of time, which may cause deflagration.

[0123] Scenario 2: Particulate matter concentration exceeds limits in two ways

[0124] When the particulate matter concentration is greater than 500 mg / m³, it is judged as a risk of "physical blockage + abnormal combustion".

[0125] Concentration > 500 mg / m³: This exceeds the monitoring concentration limit for fugitive particulate matter emissions (1.0 mg / m³) in the "Integrated Emission Standard of Air Pollutants" (GB16297-1996) by more than 500 times, indicating the generation of a large amount of coke particles or metal oxide dust.

[0126] Change rate exceeds limit: A sudden increase in dust concentration may be due to large-area peeling of the inner wall of the furnace tube or violent combustion leading to metal melting.

[0127] This application also discloses an in-situ detection system for coke gas, including a processor, wherein the processor performs the steps of the in-situ detection method for coke gas as described in any of the above embodiments.

[0128] This application also discloses a storage medium storing a program that, when executed by a processor, implements the steps of the in-situ detection method for coke gas described in any of the above embodiments.

[0129] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for in-situ detection of coking gas, characterized in that, Includes the following steps: In-situ sensors are installed at multiple openings on the exhaust pipe of the coking gas. The in-situ sensors are used to analyze the substance content of the coking gas and generate substance data. Based on the scorching command, scorching is performed according to the preset scorching time; Acquire the substance data generated by the in-situ sensor, the substance data including CO data, CO2 data, oxygen data and particulate data; The material data is filtered to obtain temporary data, which includes temporary CO data, temporary CO2 data, temporary oxygen data, and temporary particle data. If a preset data rise characteristic is found when the temporary CO data and the temporary CO2 data are matched, the charring start time is recorded. The coke data is calculated based on the temporary CO data, temporary CO2 data, and temporary particulate data. The particulate matter concentration is calculated based on the temporary particle data and the furnace tube volume. When the particulate matter concentration is less than the preset reference concentration, a stop coking warning is issued. If the coke burning data is less than the preset first reference data, a prompt to stop burning will be issued, and the burning stop time will be recorded. The latest charring time is calculated based on the charring start time and the charring stop time.

2. The in-situ detection method for coking gas according to claim 1, characterized in that, The method also includes the following steps: Based on the scorching command, scorching is performed according to the latest scorching time; The O2 content or O2 delivery speed during coking is adjusted in a positive correlation with the latest coking time; the longer the latest coking time, the faster the O2 content or O2 delivery speed during coking; the shorter the latest coking time, the slower the O2 content or O2 delivery speed during coking.

3. The in-situ detection method for coking gas according to claim 1, characterized in that, The method also includes the following steps: Based on the CO data and the CO2 data, CO and CO2 concentration curves were obtained, respectively. Integrating the CO and CO2 concentration curves yields the areas under the CO and CO2 curves, respectively. Based on the area of ​​the CO curve, the total area of ​​the CO2 curve, and the volume of the furnace tube, the cumulative mass of coke burned is calculated using the coke combustion reaction formula.

4. The in-situ detection method for coke gas according to claim 3, characterized in that, The step of filtering the material data further includes the following sub-steps. The material data is filtered by moving average using a sliding window. The width of the sliding window is adjusted inversely according to the rate of change of the mass of the burned coke; the faster the rate of change of the mass of the burned coke, the narrower the width of the sliding window; the slower the rate of change of the mass of the burned coke, the wider the width of the sliding window.

5. The in-situ detection method for coking gas according to claim 1, characterized in that, The method also includes the following steps: Calculate the rate of change of CO concentration and the rate of change of CO2 concentration; when the rate of change of CO concentration or the rate of change of CO2 concentration exceeds the corresponding threshold, issue the first warning. Calculate the O2 consumption rate, and issue a second warning when the O2 consumption rate exceeds the set consumption threshold. Calculate the attenuation coefficient of particulate matter concentration; when the attenuation coefficient of particulate matter concentration exceeds the set attenuation threshold, issue a third early warning.

6. The in-situ detection method for coking gas according to claim 1, characterized in that, The method also includes the following steps: When the CO concentration is greater than 1000 ppm and dCO / dt is greater than 50 ppm / s, the intense combustion of coke is considered to have begun, which is defined as the initial stage of coking. When the CO2 concentration is greater than 30% and the hydrocarbon concentration is less than 1000 ppm, the system enters a stable coking period, which is defined as the main reaction stage. When the CO concentration is <500ppm and the O2 concentration is >18%, and the rate of change is <10ppm / s for 10 consecutive minutes, the pre-judgment of the end of the reaction is triggered and defined as the end of the reaction.

7. The in-situ detection method for coking gas according to claim 1, characterized in that, The method also includes the following steps: If the rate of change in CO concentration is detected to be greater than the corresponding set threshold, and the CO concentration is greater than 2000 ppm, or the particulate matter concentration is greater than the corresponding set threshold, the supply of oxidation medium will be cut off.

8. An in-situ detection system for coking gas, characterized in that, Includes a processor, wherein the steps of the in-situ detection method for coke gas as described in any one of claims 1-7 are performed.

9. A storage medium, characterized in that, The medium stores a program that, when executed by a processor, implements the steps of the in-situ detection method for coke gas according to any one of claims 1-7.

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