Online automatic purification method for volatile organic compounds in coking benzene analysis

Abstract

The invention relates to the technical field of waste gas purification, in particular to an on-line automatic purification method for volatile organic compounds in coking benzene analysis, and the method comprises the following steps: collecting the flow velocity and concentration of the volatile organic compounds and the liquid level height and temperature in an adsorption tank within a preset time period before the current moment; acquiring the input mass of the volatile organic compound at each acquisition moment according to the flow velocity and concentration of the volatile organic compound at each acquisition moment; the adsorption conversion rate of the volatile organic compounds at each collection moment is obtained by analyzing the change condition of the input mass at each collection moment and the adjacent collection moment and the change condition of the liquid level height; according to the distribution condition of the adsorption conversion rate at all the collection moments, the conversion efficiency stability coefficient of the volatile organic compounds is obtained, and the temperature in the adsorption tank at the current moment is adjusted. According to the present invention, the adsorption efficiency can be improved, and the emission of volatile organic compounds can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of waste gas purification, and particularly relates to an on-line automatic purification method for volatile organic compounds in coking benzene analysis. Background Art

[0002] In the production process of coking benzene, volatile organic compounds (VOCs) are generated. Volatile organic compounds can cause teratogenesis and carcinogenesis, and can also trigger photochemical smog, causing secondary air pollution. Therefore, it is necessary to purify the volatile organic compounds generated in the production process of coking benzene.

[0003] Currently, an oil and gas recovery device is usually used to purify volatile organic compounds. The prior art adjusts the temperature in the adsorption tank by monitoring the relationship between the concentration of volatile organic compounds and the temperature in the adsorption tank of the oil and gas recovery device to ensure the adsorption effect. However, in the actual adsorption process, the adsorption capacity of the activated carbon in the adsorption tank will change, and the prior art fails to fully combine the change of the adsorption capacity of the activated carbon, resulting in incomplete purification of VOCs. Summary of the Invention

[0004] In view of the above, it is necessary to provide an on-line automatic purification method for volatile organic compounds in coking benzene analysis. Compared with the traditional purification method for volatile organic compounds in coking benzene analysis, it can not only improve the adsorption efficiency, but also effectively reduce the emission of volatile organic compounds.

[0005] An on-line automatic purification method for volatile organic compounds in coking benzene analysis of the present application adopts the following technical solutions:

[0006] An embodiment of the present application provides an on-line automatic purification method for volatile organic compounds in coking benzene analysis, and the method includes the following steps:

[0007] Within a preset time period before the current moment, collect the flow rate and concentration of volatile organic compounds, as well as the liquid level height and temperature in the adsorption tank;

[0008] Obtain the input mass of volatile organic compounds at each collection moment through the flow rate and concentration of volatile organic compounds at each collection moment;

[0009] Obtain the adsorption conversion rate of volatile organic compounds at each collection moment by analyzing the change of the input mass at each collection moment and its adjacent collection moment, as well as the change of the liquid level height;

[0010] Obtain the conversion efficiency stability coefficient of volatile organic compounds through the distribution of the adsorption conversion rate at all collection moments;

[0011] The temperature in the adsorption tank at the current moment is adjusted by the conversion efficiency stability coefficient.

[0012] In one embodiment, the input mass is the product of the flow rate and concentration of the volatile organic compounds at each collection time.

[0013] In one embodiment, the process of obtaining the adsorption conversion rate is:

[0014] According to the change of the liquid level height at each collection time and its adjacent collection time, the growth ratio of the liquid level height at each collection time is obtained, which is recorded as the first ratio;

[0015] By comparing the changes in the input mass of volatile organic compounds at each collection time and its adjacent collection time, the growth ratio of the input mass of volatile organic compounds at each collection time is obtained, which is recorded as the second ratio;

[0016] The adsorption conversion rate is the difference between the first ratio and the second ratio.

[0017] In one embodiment, the expression of the growth ratio of the liquid level height at each acquisition time is:

[0018] In the formula, Xz i Indicates the growth rate of the liquid level at the i-th collection moment; H i―1 , H i , H i+1 They represent the liquid level heights at the i-1th, i-th, and i+1th collection moments respectively; γ represents a preset value greater than 0.

[0019] In one embodiment, the process of obtaining the conversion efficiency stability coefficient is:

[0020] The collection time when the adsorption conversion rate is greater than or equal to 0 is recorded as the high-efficiency time, and the collection time when the adsorption conversion rate is less than 0 is recorded as the low-efficiency time;

[0021] Calculate the sum of the adsorption conversion rates at all acquisition times;

[0022] By comparing the discreteness of the adsorption conversion rate at all high-efficiency moments with the discreteness of the adsorption conversion rate at all low-efficiency moments, and combining the sum value, the conversion efficiency stability coefficient of volatile organic compounds is obtained.

[0023] In one embodiment, the expression of the conversion efficiency stability coefficient is:

[0024] Where W represents the conversion efficiency stability coefficient of volatile organic compounds; σZ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all efficient moments; σZQ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all inefficient moments; ε represents a constant greater than 0; n represents the total number of all acquisition moments; u i Represents the adsorption conversion rate of volatile organic compounds at the i-th collection time.

[0025] In one embodiment, the process of adjusting the temperature in the adsorption tank at the current moment is:

[0026] The initial adjustment temperature of the adsorption tank at the current moment is obtained by combining the conversion efficiency stability coefficient with the temperature in the adsorption tank at the current moment;

[0027] By comparing the initial adjustment temperature with a preset threshold, the adjustment temperature of the adsorption tank at the current moment is obtained, and the temperature in the adsorption tank at the current moment is adjusted to the adjustment temperature.

[0028] In one embodiment, the process of obtaining the initial adjustment temperature is:

[0029] Calculating the product of the normalized value of the conversion efficiency stability coefficient and a preset value;

[0030] The initial adjustment temperature is positively correlated with the product and the temperature in the adsorption tank at the current moment.

[0031] In one embodiment, the initial adjustment temperature is the product of the product and the temperature in the adsorption tank at the current moment.

[0032] In one of the embodiments, the method for obtaining the adjustment temperature is: when the initial adjustment temperature is greater than or equal to the preset threshold, the preset threshold is used as the adjustment temperature of the adsorption tank at the current moment; otherwise, the initial adjustment temperature is used as the adjustment temperature of the adsorption tank at the current moment.

[0033] This application has at least the following beneficial effects:

[0034] The present application can effectively identify the emission peak of volatile organic compounds by calculating the input mass of volatile organic compounds at each collection moment, and can accurately monitor and control the moment when the emission volume is maintained at a high level, so as to reduce the emission of volatile organic compounds; and then obtain the adsorption conversion rate of volatile organic compounds by analyzing the change in the amount of volatile organic compounds transported to the adsorption tank and the change in the liquid level height in the adsorption tank, which is used to reflect the adsorption efficiency of the activated carbon in the adsorption tank and is helpful to evaluate whether the temperature in the adsorption tank is appropriate; obtain the conversion efficiency stability coefficient through the distribution of the adsorption conversion rate of volatile organic compounds at all collection moments, Analyzing the stability of the adsorption process over a period of time based on the analysis of the suitability of the temperature in the adsorption tank at each collection moment is helpful to prevent the performance of the activated carbon in the adsorption tank from decreasing and avoid mechanical wear and chemical fatigue of the activated carbon due to frequent temperature adjustments, thereby extending the service life of the activated carbon and ensuring the long-term stability of the purification process of volatile organic compounds. Furthermore, by adjusting the temperature in the adsorption tank in real time through the conversion efficiency stability coefficient, it is possible to ensure that the activated carbon adsorbs volatile organic compounds under the best conditions, which not only improves the adsorption efficiency, but also effectively reduces the emission of volatile organic compounds, thereby reducing pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A flow chart of the steps of an online automatic purification method for volatile organic compounds in coking benzene analysis provided by the present application;

[0037] Figure 2 Schematic diagram of the process for obtaining adsorption conversion rate;

[0038] Figure 3 Schematic diagram of the acquisition process for adjusting temperature. DETAILED DESCRIPTION

[0039] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" and the like is intended to present related concepts in a concrete manner.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the present application. The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be understood that, unless otherwise specified, " / " means or.

[0041] It should also be noted that the terms "first" and "second" in the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0042] The specific scheme of the online automatic purification method of volatile organic compounds in coking benzene analysis provided by the present application is described in detail below in conjunction with the accompanying drawings.

[0043] An embodiment of the present application provides an online automatic purification method for volatile organic compounds in coking benzene analysis. Specifically, the following online automatic purification method for volatile organic compounds in coking benzene analysis is provided. Please refer to Figure 1 , the method comprises the following steps:

[0044] Step 1: Collect the flow rate and concentration of volatile organic compounds, as well as the liquid level and temperature in the adsorption tank within a preset time period before the current moment.

[0045] During the purification process of volatile organic compounds, various parameters in the adsorption tank are monitored, as follows: a flow rate sensor and a photoionization detector are installed in the air intake pipe of the adsorption tank to collect the flow rate and concentration of volatile organic compounds; a liquid level meter is installed in the adsorption tank to collect the liquid level height in the adsorption tank; a temperature sensor is installed in the adsorption tank to collect the temperature in the adsorption tank.

[0046] During a preset time period before the current moment, the flow rate and concentration of volatile organic compounds, as well as the liquid level and temperature in the adsorption tank are collected.

[0047] In this embodiment, the collection frequency of flow rate, concentration and liquid level height is 100 Hz, and the collection frequency of temperature is 1 Hz. The collection frequencies of flow rate, concentration, liquid level height and temperature are all preset manually. On the basis of ensuring that the collection frequencies of flow rate, concentration and liquid level height are the same, the implementer can set them by himself; the length of the preset time period is 1s. The length of the preset time period is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0048] Step 2: Obtain the input mass of the volatile organic compounds at each collection time through the flow rate and concentration of the volatile organic compounds at each collection time.

[0049] In the process of adsorbing volatile organic compounds by the activated carbon adsorption material in the adsorption tank, the lower the concentration of volatile organic compounds in the adsorption tank, the lower the temperature in the adsorption tank should be. Lower temperature can increase the time that volatile organic compounds stay on the surface of activated carbon, thereby improving the efficiency of adsorption; conversely, when the concentration of volatile organic compounds in the adsorption tank increases significantly, the temperature needs to be increased to avoid too fast saturation of activated carbon, thereby reducing the absorption efficiency of volatile organic compounds in the subsequent time.

[0050] Because three-stage condensation is required before adsorption of volatile organic compounds, the condensation temperature is not fixed during the condensation process, but within a range. Therefore, when transporting volatile organic compounds to the adsorption tank, the flow rate and concentration of volatile organic compounds will change to a certain extent. In addition, during the period of time when the condensation effect is better, the concentration of volatile organic compounds will be lower and the flow rate will decrease.

[0051] Based on the above analysis, the input mass of volatile organic compounds at each collection time is obtained through the flow rate and concentration of volatile organic compounds at each collection time. The expression is:

[0052] Z i =V i ×M i ; In the formula, Z i represents the input mass of volatile organic compounds at the i-th collection moment; V i 、M i They respectively represent the flow rate and concentration of volatile organic compounds at the i-th collection moment.

[0053] It should be noted that: when the product of the flow rate and concentration of volatile organic compounds is larger, the input mass of volatile organic compounds at the i-th collection time is larger, indicating that the input amount of volatile organic compounds at the i-th collection time is higher. In the purification process of volatile organic compounds, by calculating the input mass of volatile organic compounds at each collection time, the moment of maintaining high emission can be accurately monitored and controlled, which can effectively reduce the emission of volatile organic compounds and reduce pollution to the environment. At the same time, it helps to improve the recycling of resources and improve environmental protection.

[0054] Step 3, by analyzing the change of the input mass at each collection time and its adjacent collection time, as well as the change of the liquid level height, the adsorption conversion rate of the volatile organic compounds at each collection time is obtained.

[0055] When the amount of volatile organic matter delivered to the adsorption tank per unit time changes, and the liquid level in the adsorption tank also changes accordingly, it means that the activated carbon in the adsorption tank is efficiently adsorbing the volatile organic matter, converting the volatile organic matter into liquid and accumulating it in the adsorption tank. At this time, there is no need to make a large adjustment to the temperature in the adsorption tank to efficiently adsorb the volatile organic matter.

[0056] Based on the above analysis, by analyzing the changes in the input mass of volatile organic compounds at each collection time and its adjacent collection time, as well as the changes in the liquid level height, the adsorption conversion rate of volatile organic compounds at each collection time is obtained, and the expression is:

[0057] u i =Xz i ―Yz i ; In the formula, u i represents the adsorption conversion rate of volatile organic compounds at the i-th collection time; Xz i Indicates the growth rate of the liquid level at the i-th collection moment; Yz i represents the growth rate of the input mass of volatile organic compounds at the i-th collection moment. i Recorded as the first ratio, Yz i The calculation formula for the growth ratio of the liquid level at the i-th collection moment is:

[0058] In the formula, Xz i Indicates the growth rate of the liquid level at the i-th collection moment; H i―1 , H i , H i+1 They respectively represent the liquid level heights at the i-1th, i-th, and i+1th collection moments; γ represents a preset value greater than 0, which is used to avoid the denominator being 0. The value of γ is preset manually and can be set by the implementer. In this embodiment, the value of γ is 0.01.

[0059] The growth rate of the input mass of volatile organic compounds at the i-th collection moment is calculated using the same calculation method as the growth rate of the liquid level height at the i-th collection moment.

[0060] It should be noted that: when the adsorption conversion rate of volatile organic compounds is higher, it means that the adsorption efficiency of the activated carbon in the adsorption tank is higher, and the activated carbon can more effectively convert volatile organic compounds from gas to liquid and accumulate in the adsorption tank. This shows that the activated carbon in the adsorption tank is currently at a more suitable temperature, which helps to maintain efficient adsorption performance. Suitable temperature can enhance the adsorption capacity of activated carbon and improve the adsorption conversion rate, thereby reducing the emission of volatile organic compounds and protecting the environment. The schematic diagram of the process of obtaining the adsorption conversion rate is as follows Figure 2 shown.

[0061] Step 4: Obtain the conversion efficiency stability coefficient of volatile organic compounds through the distribution of the adsorption conversion rate at all collection times.

[0062] The higher the adsorption conversion rate of volatile organic compounds in the adsorption tank, the better the absorption rate of volatile organic compounds by the activated carbon in the adsorption tank. When the adsorption conversion rate of volatile organic compounds is greater than or equal to 0 at multiple collection times, it means that the original volatile organic compounds in the adsorption tank are constantly being adsorbed by the activated carbon, and the activated carbon is more adapted to the current temperature. When the adsorption conversion rate is negative, it means that the volatile organic compounds transported to the adsorption tank have not been completely absorbed. At this time, it is necessary to lower the temperature and enhance the adsorption capacity of the activated carbon in the adsorption tank, so that the absorption efficiency of the activated carbon for volatile organic compounds is improved to prevent the discharge of volatile organic compounds that have not been fully adsorbed.

[0063] Based on the above analysis, the conversion efficiency stability coefficient of volatile organic compounds is obtained through the distribution of the adsorption conversion rate of volatile organic compounds at all sampling times. The expression is:

[0064] Wherein, W represents the conversion efficiency stability coefficient of volatile organic compounds; the moment when the adsorption conversion rate of volatile organic compounds is greater than or equal to 0 is recorded as the high-efficiency moment, and the moment when the adsorption conversion rate of volatile organic compounds is less than 0 is recorded as the low-efficiency moment, σZ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all high-efficiency moments; σZQ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all low-efficiency moments; ε represents a constant preset greater than 0 to avoid the denominator being 0, and the value of ε is preset manually. In this embodiment, the value of ε is 0.01; n represents the total number of all acquisition moments; u i Represents the adsorption conversion rate of volatile organic compounds at the i-th collection time.

[0065] In this embodiment, in the process of calculating the stability coefficient of the conversion efficiency of volatile organic compounds, all the discrete degrees involved are standard deviations. As other implementation methods, on the basis of being able to measure the uneven distribution of the adsorption conversion rate of volatile organic compounds at all high-efficiency moments and the uneven distribution of the adsorption conversion rate of volatile organic compounds at all low-efficiency moments, the implementer may adopt other existing technologies for measurement, such as variance, coefficient of variation, etc., and this application does not impose any special restrictions.

[0066] It should be noted that: when the conversion efficiency stability coefficient of volatile organic compounds is larger, it means that the activated carbon in the adsorption tank is more stable in adsorbing volatile organic compounds, and the activated carbon can continuously and effectively convert volatile organic compounds from gas to liquid and accumulate them in the adsorption tank. This indicates that the activated carbon in the adsorption tank is currently at a more suitable temperature and does not require a large temperature adjustment. In addition, a stable adsorption process can also prevent the performance of the activated carbon in the adsorption tank from deteriorating, ensuring the long-term stability of the purification process.

[0067] Step 5: adjusting the temperature in the adsorption tank at the current moment by using the conversion efficiency stability coefficient.

[0068] Furthermore, the initial adjustment temperature of the adsorption tank at the current moment is obtained by combining the conversion efficiency stability coefficient of volatile organic compounds with the temperature in the adsorption tank at the current collection moment. The expression is:

[0069] T = a × sigmoid (W) × t; where T represents the initial adjustment temperature of the adsorption tank at the current moment; a represents the preset value; sigmoid() represents the sigmoid function; W represents the conversion efficiency stability coefficient of volatile organic compounds; t represents the temperature in the adsorption tank at the current collection moment. a × sigmoid() is used to map the conversion efficiency stability coefficient of volatile organic compounds to [0, a]. In order to avoid excessive temperature changes during the temperature adjustment process, the value of a in this embodiment is 2.

[0070] It should be noted that: when the conversion efficiency stability coefficient of volatile organic compounds is 0, it means that the volatile organic compounds in the adsorption tank are being steadily adsorbed by the activated carbon, so the value of a×sigmoid(W) is 1, and there is no need to adjust the temperature in the adsorption tank to avoid affecting the efficient adsorption of the activated carbon in the adsorption tank; when the conversion efficiency stability coefficient of volatile organic compounds is greater than 0, it means that the volatile organic compounds transported to the adsorption tank are being rapidly absorbed, that is, the value of a×sigmoid(W) is greater than 1. In order to avoid the activated carbon from being saturated too quickly and affecting the performance of the activated carbon, it is necessary to increase the temperature in the adsorption tank and reduce the adsorption efficiency of the activated carbon; when the conversion efficiency stability coefficient of volatile organic compounds is less than 0, it means that the volatile organic compounds transported to the adsorption tank cannot be quickly absorbed, that is, the value of a×sigmoid(W) is less than 1. In order to improve the adsorption efficiency of the activated carbon, it is necessary to reduce the temperature in the adsorption tank.

[0071] Furthermore, since the adsorption capacity of activated carbon is greatly affected by temperature, generally as the temperature increases, the adsorption capacity of activated carbon will gradually decrease. Therefore, the temperature of activated carbon should not be too high, that is, the temperature in the adsorption tank should not be too high. Therefore, by comparing the initial adjustment temperature of the adsorption tank with the preset threshold, the adjustment temperature of the adsorption tank at the current moment is obtained, and the expression is:

[0072] In the formula, T′ represents the current adjustment temperature of the adsorption tank; Tu represents the preset threshold; T represents the initial adjustment temperature of the adsorption tank at the current moment. The schematic diagram of the acquisition process of the adjustment temperature is as follows: Figure 3 shown.

[0073] The temperature in the adsorption tank at the current moment is adjusted to the adjustment temperature through the temperature control system on the adsorption tank.

[0074] In summary, the present application can effectively identify the emission peak of volatile organic compounds by calculating the input mass of volatile organic compounds at each collection moment, and can accurately monitor and control the moment when high emission is maintained, so as to reduce the emission of volatile organic compounds; then, by analyzing the change in the amount of volatile organic compounds transported to the adsorption tank and the change in the liquid level height in the adsorption tank, the adsorption conversion rate of volatile organic compounds is obtained, which is used to reflect the adsorption efficiency of the activated carbon in the adsorption tank and helps to evaluate whether the temperature in the adsorption tank is appropriate; through the distribution of the adsorption conversion rate of volatile organic compounds at all collection moments, the stability of the conversion efficiency is obtained. The coefficient, based on the analysis of the suitability of the temperature in the adsorption tank at each collection moment, analyzes the stability of the adsorption process over a period of time, which is beneficial to prevent the performance of the activated carbon in the adsorption tank from declining, and avoids mechanical wear and chemical fatigue of the activated carbon due to frequent temperature adjustment, thereby extending the service life of the activated carbon and ensuring the long-term stability of the purification process of volatile organic compounds; further, through the conversion efficiency stability coefficient, the temperature in the adsorption tank is adjusted in real time, which can ensure that the activated carbon adsorbs volatile organic compounds under the best condition, which can not only improve the adsorption efficiency, but also effectively reduce the emission of volatile organic compounds, thereby reducing pollution to the environment.

[0075] The flowchart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to the embodiment of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowchart and the block diagram in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in a different order from the order disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0076] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic features of the present application. Therefore, no matter from which point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. An online automatic purification method for volatile organic compounds in coking benzene analysis, characterized in that: The method comprises the following steps: Collect the flow rate and concentration of volatile organic compounds, as well as the liquid level and temperature in the adsorption tank within a preset time period before the current moment; The input mass of volatile organic compounds at each collection time is obtained through the flow rate and concentration of volatile organic compounds at each collection time; By analyzing the change of the input mass at each collection time and its adjacent collection time, as well as the change of the liquid level height, the adsorption conversion rate of the volatile organic matter at each collection time is obtained; Obtaining the conversion efficiency stability coefficient of volatile organic compounds through the distribution of the adsorption conversion rate at all collection moments; The temperature in the adsorption tank at the current moment is adjusted by the conversion efficiency stability coefficient.

2. The method for online automatic purification of volatile organic compounds in coking benzene analysis according to claim 1, characterized in that: The input mass is the product of the flow rate and the concentration of the volatile organic compounds at each collection time.

3. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 1, characterized in that: The process of obtaining the adsorption conversion rate is: According to the change of the liquid level height at each collection time and its adjacent collection time, the growth ratio of the liquid level height at each collection time is obtained, which is recorded as the first ratio; By comparing the changes in the input mass of volatile organic compounds at each collection time and its adjacent collection time, the growth ratio of the input mass of volatile organic compounds at each collection time is obtained, which is recorded as the second ratio; The adsorption conversion rate is the difference between the first ratio and the second ratio.

4. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 3, characterized in that: The expression of the growth ratio of the liquid level height at each acquisition time is: In the formula, Xz i Indicates the growth rate of the liquid level at the i-th collection moment; H i―1 , H i , H i+1 They represent the liquid level heights at the i-1th, i-th, and i+1th collection moments respectively; γ represents a preset value greater than 0.

5. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 1, characterized in that: The process of obtaining the conversion efficiency stability coefficient is as follows: The collection time when the adsorption conversion rate is greater than or equal to 0 is recorded as the high-efficiency time, and the collection time when the adsorption conversion rate is less than 0 is recorded as the low-efficiency time; Calculate the sum of the adsorption conversion rates at all acquisition times; By comparing the discreteness of the adsorption conversion rate at all high-efficiency moments with the discreteness of the adsorption conversion rate at all low-efficiency moments, and combining the sum value, the conversion efficiency stability coefficient of volatile organic compounds is obtained.

6. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 5, characterized in that: The expression of the conversion efficiency stability coefficient is: Where W represents the conversion efficiency stability coefficient of volatile organic compounds; σZ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all efficient moments; σZQ represents the discrete degree of the adsorption conversion rate of volatile organic compounds at all inefficient moments; ε represents a constant greater than 0; n represents the total number of all acquisition moments; u i Represents the adsorption conversion rate of volatile organic compounds at the i-th collection time.

7. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 1, characterized in that: The process of adjusting the temperature in the adsorption tank at the current moment is as follows: The initial adjustment temperature of the adsorption tank at the current moment is obtained by combining the conversion efficiency stability coefficient with the temperature in the adsorption tank at the current moment; By comparing the initial adjustment temperature with a preset threshold, the adjustment temperature of the adsorption tank at the current moment is obtained, and the temperature in the adsorption tank at the current moment is adjusted to the adjustment temperature.

8. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 7, characterized in that: The process of obtaining the initial adjustment temperature is as follows: Calculating the product of the normalized value of the conversion efficiency stability coefficient and a preset value; The initial adjustment temperature is positively correlated with the product and the temperature in the adsorption tank at the current moment.

9. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 8, characterized in that: The initial adjustment temperature is the product of the product and the temperature in the adsorption tank at the current moment.

10. The online automatic purification method for volatile organic compounds in coking benzene analysis according to claim 7, characterized in that: The method for obtaining the adjustment temperature is: when the initial adjustment temperature is greater than or equal to the preset threshold, the preset threshold is used as the adjustment temperature of the adsorption tank at the current moment; otherwise, the initial adjustment temperature is used as the adjustment temperature of the adsorption tank at the current moment.

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