Method for controlling inlet concentration and bed temperature of low-temperature catalytic oxidation device

Abstract

The invention provides a method for controlling inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method comprises the following steps: (1) collecting and inputting initial data; (2) determining a time step length in combination with initial data and a difference method; (3) calculating relevant parameters of the catalytic bed by combining the actual inlet concentration of the device and the actual airflow temperature of the catalytic bed; (4) judging whether the gas temperature at the outlet of the catalytic bed reaches the standard or not according to the relevant parameters of the catalytic bed obtained in the step (3); if the standard is reached, ending the calculation; and if not, the step (3) is continued after the variable parameters are adjusted. According to the method provided by the invention, the inlet concentration and the bed temperature of the low-temperature catalytic oxidation device are accurately controlled by combining actual data with the simulated iterative calculation process, the efficient and safe operation of the low-temperature catalytic oxidation device is ensured, and the stability of the low-temperature catalytic oxidation process is further improved.

Description

Technical Field

[0001] The invention belongs to the field of process production safety control, and in particular relates to a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. Background Art

[0002] In recent years, with the rapid development of industrialization, the problem of waste gas emissions has become increasingly serious, among which the emission of volatile organic compounds (VOCs) has caused great damage to the atmospheric environment. As an effective means of VOCs treatment, low-temperature catalytic oxidation technology has been widely used at home and abroad. However, in the catalytic oxidation process, the inlet concentration and bed temperature are the key factors affecting the treatment effect. Therefore, achieving precise control of the inlet concentration and bed temperature is of great significance for improving treatment efficiency, reducing energy consumption and ensuring the stability of catalytic oxidation.

[0003] Low-temperature catalytic oxidation refers to the process of converting organic matter into carbon dioxide and water by reacting with oxygen at a relatively low temperature through the action of a catalyst. Compared with the traditional regenerative thermal oxidation (RTO) process, the currently popularized regenerative catalytic oxidation (RCO) process changes the combustion mode from traditional high-temperature flame combustion to smokeless combustion, greatly reducing the generation of nitrogen oxides, and can reduce the ignition temperature from 200-400℃ to 600-900℃, and the combustion temperature from 600-800℃ to 300-500℃, effectively reducing energy consumption. The reduction in production temperature also provides more guarantees for the establishment of a safe production monitoring feedback mechanism, which can extend the service life of real-time monitoring equipment and thus reduce production risks. In the low-temperature catalytic oxidation process, the catalyst is a key factor, and its activity is affected by multiple factors such as temperature, pressure, and inlet concentration. Therefore, precise control of the inlet concentration and bed temperature and the establishment of a real-time monitoring feedback mechanism can improve the activity of the catalyst, thereby improving the efficiency of catalytic oxidation.

[0004] Inlet concentration control requires pre-treatment of the exhaust gas entering the catalytic oxidation equipment to remove impurities, such as dust removal and dehumidification, so as to control the inlet concentration. Common treatment methods for removing impurities in the air flow include filtration and adsorption. By controlling the inlet concentration, the toxic effect on the catalyst can be reduced, the service life of the catalyst can be extended, and energy consumption and pollutant emissions can also be reduced.

[0005] Bed temperature control technology refers to the technology of heating or cooling by adjusting the heating power of the device to achieve precise control of the bed temperature. In the catalytic oxidation process, temperature is an important reaction condition. Temperature changes will affect the activity of the catalyst and the conversion rate of organic matter.

[0006] In summary, it is necessary to provide a method for accurately controlling the inlet concentration and bed temperature of low-temperature catalytic oxidation equipment, so as to achieve accurate control of the inlet concentration and bed temperature of low-temperature catalytic oxidation equipment, improve processing efficiency, reduce energy consumption and ensure the stability of catalytic oxidation. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method realizes precise control of the inlet concentration and bed temperature of a low-temperature catalytic oxidation device by combining actual data with a simulated iterative calculation process, thereby ensuring the efficient and safe operation of the low-temperature catalytic oxidation device and further improving the stability of the low-temperature catalytic oxidation process.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device, the method comprising the following steps:

[0010] (1) Collect and input initial data;

[0011] (2) Determine the time step by combining the initial data and the difference method;

[0012] (3) calculating relevant parameters of the catalytic bed in combination with the actual inlet concentration of the device and the actual air flow temperature of the catalytic bed;

[0013] (4) judging whether the gas temperature at the outlet of the catalyst bed meets the standard according to the relevant parameters of the catalyst bed obtained in step (3);

[0014] If the standard is met, the calculation is terminated; if the standard is not met, the variable parameters are adjusted and step (3) is continued.

[0015] In the present invention, by combining actual operating data (initial data, actual airflow temperature and actual inlet concentration) and an iterative calculation process (calculation of the time step and calculation of relevant parameters of the catalytic bed), accurate and sensitive control of the inlet concentration and bed temperature of the low-temperature catalytic oxidation device is achieved, thereby avoiding problems such as explosion of the low-temperature catalytic oxidation device due to operating parameter setting problems during operation, ensuring the efficient and safe operation of the low-temperature catalytic oxidation device, further improving the stability of the low-temperature catalytic oxidation process, and reducing energy consumption.

[0016] Furthermore, the present invention achieves sensitive control of the parameters of the low-temperature catalytic oxidation device by combining actual production data with theoretical simulation.

[0017] As a preferred technical solution of the present invention, the method is carried out in Matlab software.

[0018] As a preferred technical solution of the present invention, at least two catalyst beds are arranged inside the low-temperature catalytic oxidation device.

[0019] As a preferred technical solution of the present invention, the initial data includes initial device data and initial material data.

[0020] Preferably, the initial plant data includes bed dimensions.

[0021] Preferably, the initial material data includes: the initial temperature and initial thermophysical property parameters of the exhaust gas to be treated that is introduced into the low-temperature catalytic oxidation device.

[0022] Preferably, the initial thermophysical property parameters include initial calorific value, gas-solid heat transfer coefficient, gas phase temperature, solid phase temperature, gas phase thermal conductivity and solid phase thermal conductivity.

[0023] As a preferred technical solution of the present invention, the actual air flow temperature in step (3) is provided by a temperature sensor arranged on the surface of each catalyst bed layer.

[0024] Preferably, the temperature sensor includes one first temperature sensor and four second temperature sensors.

[0025] Preferably, the first temperature sensor is arranged at the center point of the catalytic bed.

[0026] Preferably, the second temperature sensor is arranged in a windmill shape at the boundary line of the catalytic bed.

[0027] Preferably, the second temperature sensor is arranged at 1 / 4 of the boundary line of the catalytic bed.

[0028] Preferably, the actual air flow temperature in step (3) is an average value of the temperatures provided by the first temperature sensor and the second temperature sensor.

[0029] As a preferred technical solution of the present invention, the actual inlet concentration in step (3) is provided by a concentration sensor provided at the inlet of the low-temperature catalytic oxidation device.

[0030] In the present invention, the inlet concentration of the exhaust gas delivered to the room temperature catalytic oxidation device needs to be pretreated to achieve the purpose of controlling the inlet concentration. Commonly used pretreatment methods include filtration, adsorption, etc.; by accurately controlling the inlet concentration, the poisoning effect on the catalyst in the catalytic reaction can be reduced and the service life of the catalyst can be extended; at the same time, energy consumption and pollutant emissions can also be reduced.

[0031] As a preferred technical solution of the present invention, the calculation of the relevant parameters of the catalytic bed in step (3) includes: sequentially calculating the heat flux density on the surface of the catalytic bed, the thermophysical parameters of the center point inside the catalytic bed, and the temperature of the catalytic bed.

[0032] In the present invention, the surface heat flux density of the catalyst bed includes the surface heat flux density of the catalyst bed above and below and before and after;

[0033] The catalyst bed temperature is calculated by a difference equation.

[0034] As a preferred technical solution of the present invention, the thermophysical parameters include specific heat capacity and thermal conductivity.

[0035] Preferably, the catalyst bed temperature includes the bed axial distance temperature and the bed lateral distance temperature.

[0036] As a preferred technical solution of the present invention, the standard for the gas temperature at the outlet of the catalyst bed in step (4) is:

[0037] The gas temperature at the outlet of the catalyst bed is ≤ the standard temperature of the catalyst bed + 40°C.

[0038] As a preferred technical solution of the present invention, the variable parameters in step (4) include: the actual air flow temperature of the catalyst bed, the actual inlet concentration of the device and the actual feed flow rate of the device.

[0039] In the present invention, methods for adjusting the actual inlet concentration of the device include: supplementing with fresh air to dilute the inlet concentration, emergency emptying of part of the high-concentration inlet airflow, etc.; methods for adjusting the actual airflow temperature of the catalytic bed include: adjusting the heating power of the device, introducing back-blowing cool air into the device, etc.; methods for adjusting the actual feed flow rate include: regulating the fan to reduce the inlet air volume.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The method provided by the present invention can achieve precise control of the inlet concentration and the catalyst bed temperature, thereby improving the catalytic oxidation treatment efficiency and reducing pollutant emissions;

[0042] (2) The method provided by the present invention can extend the service life of the catalyst and reduce the operating cost by accurately controlling the inlet concentration and bed temperature;

[0043] (3) The method provided by the present invention has high stability and reliability and can adapt to various complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flow chart of a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device provided by the present invention;

[0045] Figure 2 It is a distribution diagram of the catalyst bed surface temperature sensor provided by the present invention;

[0046] Among them, 1 is the first temperature sensor, and 2 is the second temperature sensor. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] In one specific embodiment, the present invention provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device, which is performed in Matlab software, such as Figure 1 As shown, the specific steps include:

[0049] (1) Collect and input initial data;

[0050] The initial data include the size of the catalytic bed, the initial temperature and initial thermophysical parameters of the exhaust gas to be treated introduced into the low-temperature catalytic oxidation device;

[0051] The initial thermophysical parameters include initial calorific value, gas-solid heat transfer coefficient, gas phase temperature, solid phase temperature, gas phase thermal conductivity and solid phase thermal conductivity;

[0052] (2) Determine the time step by combining the initial data and the difference method;

[0053] (3) calculating the heat flux density on the surface of the catalyst bed, the thermophysical parameters of the center point inside the catalyst bed, and the temperature of the catalyst bed based on the actual inlet concentration of the device and the actual gas flow temperature of the catalyst bed;

[0054] The actual air flow temperature is provided by a temperature sensor disposed on the surface of each catalyst bed; Figure 2 As shown, the temperature sensor includes 1 first temperature sensor and 4 second temperature sensors, the first temperature sensor is arranged at the center point of the catalytic bed layer, the second temperature sensor is arranged in a windmill shape at the boundary line of the catalytic bed layer, and the second temperature sensor is arranged at 1 / 4 of the boundary line of the catalytic bed layer;

[0055] The actual air flow temperature is an average value of the temperatures provided by the first temperature sensor and the second temperature sensor;

[0056] The actual inlet concentration is provided by a concentration sensor provided at the inlet of the low-temperature catalytic oxidation device;

[0057] The thermophysical parameters include specific heat capacity and thermal conductivity; the catalyst bed temperature includes the bed axial distance temperature and the bed lateral distance temperature;

[0058] (4) judging whether the gas temperature at the outlet of the catalyst bed meets the standard according to the relevant parameters of the catalyst bed obtained in step (3);

[0059] The standard for the gas temperature at the outlet of the catalyst bed is: the gas temperature at the outlet of the catalyst bed ≤ the standard temperature of the catalyst bed + 40°C;

[0060] If the standard is met, the calculation is terminated; if the standard is not met, the variable parameters are adjusted and step (3) is continued;

[0061] The variable parameters include: the actual air flow temperature of the catalyst bed, the actual inlet concentration of the device and the actual feed flow rate of the device.

[0062] Example 1

[0063] This embodiment provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method is performed in Matlab software and specifically includes the following steps:

[0064] (1) Collect and input initial data;

[0065] The initial data include the size of the catalytic bed, the initial temperature and initial thermophysical parameters of the exhaust gas to be treated introduced into the low-temperature catalytic oxidation device;

[0066] The initial thermophysical parameters include initial calorific value, gas-solid heat transfer coefficient, gas phase temperature, solid phase temperature, gas phase thermal conductivity and solid phase thermal conductivity;

[0067] (2) Determine the time step by combining the initial data and the difference method;

[0068] (3) calculating the heat flux density on the surface of the catalyst bed, the thermophysical parameters of the center point inside the catalyst bed, and the temperature of the catalyst bed based on the actual inlet concentration of the device and the actual gas flow temperature of the catalyst bed;

[0069] The actual air flow temperature is provided by a temperature sensor disposed on the surface of each catalyst bed; Figure 2 As shown, the temperature sensor includes 1 first temperature sensor and 4 second temperature sensors, the first temperature sensor is arranged at the center point of the catalytic bed layer, the second temperature sensor is arranged in a windmill shape at the boundary line of the catalytic bed layer, and the second temperature sensor is arranged at 1 / 4 of the boundary line of the catalytic bed layer;

[0070] The actual air flow temperature is an average value of the temperatures provided by the first temperature sensor and the second temperature sensor;

[0071] The actual inlet concentration is provided by a concentration sensor provided at the inlet of the low-temperature catalytic oxidation device;

[0072] The thermophysical parameters include specific heat capacity and thermal conductivity; the catalyst bed temperature includes the bed axial distance temperature and the bed lateral distance temperature;

[0073] (4) judging whether the gas temperature at the outlet of the catalyst bed meets the standard according to the relevant parameters of the catalyst bed obtained in step (3);

[0074] The standard for the gas temperature at the outlet of the catalyst bed is: the gas temperature at the outlet of the catalyst bed ≤ the standard temperature of the catalyst bed + 40°C;

[0075] If the standard is met, the calculation is terminated; if the standard is not met, the variable parameters are adjusted and step (3) is continued;

[0076] The variable parameters include: the actual air flow temperature of the catalyst bed, the actual inlet concentration of the device and the actual feed flow rate of the device.

[0077] Example 2

[0078] This embodiment provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method is different from that of Embodiment 1 only in that:

[0079] In this embodiment, the distribution of the temperature sensors in step (3) is adjusted as follows: a first temperature sensor is arranged at the center point of the catalyst bed layer, and second temperature sensors are independently arranged at the midpoints of the four sides of the catalyst bed layer.

[0080] Example 3

[0081] This embodiment provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method is different from that of Embodiment 1 only in that:

[0082] In this embodiment, the distribution of the temperature sensors in step (3) is adjusted as follows: the first temperature sensor disposed at the center point of the catalytic bed is omitted.

[0083] Example 4

[0084] This embodiment provides a method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device. The method is different from that of Embodiment 1 only in that:

[0085] In this embodiment, the distribution of the temperature sensors in step (3) is adjusted as follows: the provision of the second temperature sensor is omitted.

[0086] Compared with Example 1, Examples 2-4 adjust the distribution position or number of temperature sensors, which will lead to inaccurate and unbalanced temperature feedback data, causing inaccurate bed temperature calculation data, and unable to timely feedback and adjust the control inlet concentration and bed temperature, thereby failing to ensure the safe operation of the device.

[0087] In summary, the method provided by the present invention realizes precise control of the inlet concentration and bed temperature of the low-temperature catalytic oxidation device by combining actual data with the simulation iterative calculation process, ensures the efficient and safe operation of the low-temperature catalytic oxidation device, and further improves the stability of the low-temperature catalytic oxidation process.

[0088] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for controlling the inlet concentration and bed temperature of a low-temperature catalytic oxidation device, characterized in that: The method comprises the following steps: (1) Collect and input initial data; (2) Determine the time step by combining the initial data and the difference method; (3) calculating relevant parameters of the catalytic bed in combination with the actual inlet concentration of the device and the actual air flow temperature of the catalytic bed; (4) judging whether the gas temperature at the outlet of the catalyst bed meets the standard according to the relevant parameters of the catalyst bed obtained in step (3); If the standard is met, the calculation is terminated; if the standard is not met, the variable parameters are adjusted and step (3) is continued.

2. The method according to claim 1, characterized in that At least two catalyst beds are arranged inside the low-temperature catalytic oxidation device.

3. The method according to claim 1 or 2, characterized in that: The initial data includes initial device data and initial material data.

4. The method according to claim 3, characterized in that The initial plant data include catalyst bed dimensions; Preferably, the initial material data includes: the initial temperature and initial thermophysical property parameters of the exhaust gas to be treated introduced into the low-temperature catalytic oxidation device; Preferably, the initial thermophysical property parameters include initial calorific value, gas-solid heat transfer coefficient, gas phase temperature, solid phase temperature, gas phase thermal conductivity and solid phase thermal conductivity.

5. The method according to any one of claims 1 to 4, characterized in that: The actual air flow temperature in step (3) is provided by a temperature sensor disposed on the surface of each catalyst bed layer; Preferably, the temperature sensor includes 1 first temperature sensor and 4 second temperature sensors; Preferably, the first temperature sensor is arranged at the center point of the catalytic bed; Preferably, the second temperature sensor is arranged in a windmill shape at the boundary line of the catalytic bed; Preferably, the second temperature sensor is arranged at 1 / 4 of the boundary line of the catalytic bed; Preferably, the actual air flow temperature in step (3) is an average value of the temperatures provided by the first temperature sensor and the second temperature sensor.

6. The method according to any one of claims 1 to 5, characterized in that: The actual inlet concentration in step (3) is provided by a concentration sensor provided at the inlet of the low-temperature catalytic oxidation device.

7. The method according to any one of claims 1 to 6, characterized in that: The step (3) of calculating the relevant parameters of the catalytic bed comprises: sequentially calculating the heat flux density on the surface of the catalytic bed, the thermophysical parameters of the center point inside the catalytic bed, and the temperature of the catalytic bed.

8. The method according to claim 7, characterized in that The thermophysical parameters include specific heat capacity and thermal conductivity; Preferably, the catalyst bed temperature includes the bed axial distance temperature and the bed lateral distance temperature.

9. The method according to any one of claims 1 to 8, characterized in that: The standard for the gas temperature at the outlet of the catalyst bed in step (4) is: The gas temperature at the outlet of the catalyst bed is ≤ the standard temperature of the catalyst bed + 40°C.

10. The method according to any one of claims 1 to 9, characterized in that: The variable parameters in step (4) include: the actual air flow temperature of the catalyst bed, the actual inlet concentration of the device, and the actual feed flow rate of the device.

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