Automatic control device for flue gas balance system of activated coke adsorption tower

Abstract

The present invention belongs to the field of environmental protection production automation control, and in particular, relates to an automatic control device for a flue gas balance system of an activated coke adsorption tower, which is characterized by comprising a gas flow meter and a flow transmitter arranged on the outlet main pipe of a booster fan, a pressure transmitter on the inlet branch pipe of each adsorption unit air inlet chamber, a pressure transmitter and a thermal resistor of each adsorption unit transition air chamber, a pressure transmitter on the outlet branch pipe of each adsorption unit air outlet chamber, an electric butterfly valve on the outlet branch pipe of each adsorption unit air outlet chamber, and pressure transmitters, thermal resistors and electric butterfly valves at different positions of each adsorption unit are all connected to a PLC system. The present invention is not affected by the steps of component processing, manufacturing, assembly, welding, etc. of each adsorption unit, and realizes the measurement of the resistance coefficient ζ of each adsorption unit under actual production conditions, thereby obtaining the flue gas flow of each adsorption unit, and controlling the flue gas volume by adjusting the outlet electric butterfly valve, thereby truly realizing the automatic control of the flue gas balance system of the attached tower.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection production automation control, and in particular relates to an automatic control device for a flue gas balance system of an activated coke adsorption tower. Background Art

[0002] With the implementation of ultra-low emission standards for industrial flue gas, flue gas purification systems have gradually become an essential process for sintering and thermal power generation. Currently, flue gas purification mainly includes dry, semi-dry and wet desulfurization processes. In recent years, more and more flue gas purification projects have adopted the activated coke dry desulfurization process, and the activated coke dry desulfurization process has become the mainstream process for flue gas purification. In the activated coke flue gas purification project, the adsorption tower is the core equipment, because the flue gas purification is completed in the adsorption unit of the adsorption tower. The flue gas is fully in contact with the activated coke in the adsorption unit, and the SO2 and NO in the flue gas are removed by the adsorption of the activated coke. X , dust, etc., to complete the flue gas purification. Because the sintering flue gas volume is relatively large, the normal adsorption tower is composed of multiple independent parallel adsorption units. The flue gas is divided into multiple routes to enter each adsorption unit. SO2, NO X , dust and other pollutants are adsorbed by the activated carbon layer or catalytically reacted to generate harmless substances, and flue gas purification is completed in each adsorption unit. According to multiple on-site feedback, when the flue gas entering each adsorption unit is unbalanced, the pollutants in the purified flue gas will exceed the standard, and the operator can only adjust the opening of the outlet valve of each adsorption unit based on experience. After adjustment, only the pressure difference between the inlet and outlet of the adsorption unit can be observed to change, but it is unclear whether the balance is achieved, especially in SO2 or NO X When emissions exceed the standard, it is unclear which adsorption unit has exceeded the standard, and the operator can only try to adjust it little by little based on experience. This brings trouble to the actual operators and causes emissions to exceed the standard for too long, and even the Environmental Protection Agency requires production to be suspended for rectification.

[0003] Therefore, it is very important to balance the flue gas entering each adsorption unit of the adsorption tower. However, the current situation is that we can only manually adjust the opening of the outlet valve based on experience by looking at the pressure difference between the inlet and outlet of the adsorption unit. Sometimes, the inlet and outlet pressure difference values ​​of each adsorption unit are the same, but the flue gas is still unbalanced (emissions exceed the standard), which brings great pressure and confusion to actual production. Therefore, the development of an online, real-time automatic control device for the flue gas balance system of the activated coke adsorption tower has important practical significance and value. Summary of the invention

[0004] The purpose of the present invention is to provide an automatic control device for the flue gas balance system of an activated coke adsorption tower to solve the problem of slow operation adjustment after the flue gas of each adsorption unit between the adsorption towers is unbalanced, which can improve the productivity of the purification system, shorten the time of abnormal emission exceeding the standard, and make the flue gas purification system run stably and efficiently.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The automatic control device of the flue gas balance system of the activated coke adsorption tower of the present invention is characterized in that it includes a gas flow meter and a flow transmitter arranged on the booster fan outlet main pipe, a pressure transmitter respectively arranged on the inlet branch pipe of each adsorption unit air inlet chamber, a pressure transmitter and a thermal resistor respectively arranged on the transition air chamber of each adsorption unit, a pressure transmitter respectively arranged on the outlet branch pipe of each adsorption unit air outlet chamber, and an electric butterfly valve respectively arranged on the outlet branch pipe of each adsorption unit air outlet chamber, and the pressure transmitters, thermal resistors and electric butterfly valves at different positions of each adsorption unit are all connected to the PLC system.

[0007] The PLC system measures the resistance coefficient ζ of each adsorption unit. By measuring the air volume, inlet and outlet pressures, transition chamber pressure and temperature of the adsorption tower, the resistance coefficient ζ1 of the first adsorption unit is measured according to Formula 7, and the result is:

[0008]

[0009] Q 单 ...air volume passing through the adsorption unit per unit time (m 3 / h);

[0010] S1…Effective area of ​​the grille plate on the air inlet side of the first coke bed in the first adsorption unit (m 2 );

[0011] P 11 …pressure at the inlet of adsorption unit No. 1 PT-11 (Pa);

[0012] P 12 …The pressure at the outlet of adsorption unit No. 1 is PT-12 (Pa);

[0013] P 13 …The pressure of the transition chamber of adsorption unit No. 1 is PT-13 (Pa);

[0014] T 11 …Temperature of transition chamber of adsorption unit No. 1 TE-11 (℃);

[0015] P0…local standard atmospheric pressure (generally 101325) (Pa);

[0016] ρ 标 ...The density of smoke under standard conditions (generally 1.29) (Kg / m 3 );

[0017] g…Local gravity acceleration (usually 9.8) (m / s 2 );

[0018] According to the above steps, the resistance coefficients of the second, third and fourth adsorption units ζ2 / ζ3 / ζ4 are measured respectively, and the resistance coefficients of each adsorption unit are determined. The resistance coefficients of each adsorption unit are assigned to the flow rate calculation formula 5 corresponding to the PLC, and then:

[0019]

[0020] Where x is the corresponding adsorption unit number.

[0021] Advantages of the present invention:

[0022] (1) The automatic control device for the flue gas balance system of the activated coke adsorption tower of the present invention is not affected by the steps of component processing, manufacturing, assembly, welding, etc. of each adsorption unit, and the resistance coefficient ζ of each adsorption unit can be measured under actual production conditions;

[0023] (2) The automatic control device for the flue gas balance system of the activated coke adsorption tower of the present invention is designed so that the flow rate in the adsorption unit is calculated based on relevant data, and a flow meter is not required. The device has a small footprint, low investment, and a wider application range (new construction or renovation of old projects).

[0024] (3) The automatic control device of the flue gas balance system of the activated coke adsorption tower of the present invention realizes the same flue gas flow rate in each adsorption unit (within the stable zone), and the adsorption tower is adaptive to the amount of flue gas to be treated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of the adsorption tower flue gas balance control process.

[0026] Figure 2 This is a schematic diagram of the distribution of flue gas in the adsorption unit of the present invention. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

[0028] like Figure 1 , 2As shown, the automatic control device of the flue gas balance system of the activated coke adsorption tower of the present invention is characterized in that it includes a gas flow meter FE-10 and a flow transmitter FT-10 arranged on the outlet main pipe of the booster fan 1, pressure transmitters PT-11, PT-21, PT-31 and PT-41 respectively arranged on the inlet branch pipe of each adsorption unit inlet chamber, pressure transmitters PT-13, PT-23, PT-33 and PT-43 respectively arranged on the transition air chamber of each adsorption unit, and a thermal resistor TE-1 1. TE-21, TE-31 and TE-41, pressure transmitters PT-12, PT-22, PT-32 and PT-42 are respectively arranged on the outlet branch pipe of each adsorption unit, and electric butterfly valves HV / HZ-11, HV / HZ-21, HV / HZ-31 and HV / HZ-41 are respectively arranged on the outlet branch pipe of each adsorption unit. The pressure transmitters, thermal resistors and electric butterfly valves at different positions of each adsorption unit are all connected to the PLC system XIC11.

[0029] The PLC system XIC11 measures the resistance coefficient ζ of each adsorption unit. By measuring the adsorption tower processing air volume and inlet and outlet pressures, transition chamber pressure and temperature, according to Formula 7, the resistance coefficient ζ1 of the first adsorption unit is measured, and then:

[0030]

[0031] Q 单 ...air volume passing through the adsorption unit per unit time (m 3 / h);

[0032] S1…Effective area of ​​the grille plate on the air inlet side of the first coke bed in the first adsorption unit (m 2 );

[0033] P 11 …pressure at the inlet of adsorption unit No. 1 PT-11 (Pa);

[0034] P 12 …The pressure at the outlet of adsorption unit No. 1 is PT-12 (Pa);

[0035] P 13 …The pressure of the transition chamber of adsorption unit No. 1 is PT-13 (Pa);

[0036] T 11 …Temperature of transition chamber of adsorption unit No. 1 TE-11 (℃);

[0037] P0…local standard atmospheric pressure (generally 101325) (Pa);

[0038] ρ 标 ...The density of smoke under standard conditions (generally 1.29) (Kg / m3 );

[0039] g…Local gravity acceleration (usually 9.8) (m / s 2 );

[0040] According to the above steps, the resistance coefficients of the second, third and fourth adsorption units ζ2 / ζ3 / ζ4 are measured respectively, and the resistance coefficients of each adsorption unit are determined. The resistance coefficients of each adsorption unit are assigned to the flow rate calculation formula 5 corresponding to the PLC, and then:

[0041]

[0042] Where x is the corresponding adsorption unit number.

[0043] The automatic control device of the flue gas balance system of the activated coke adsorption tower of the present invention is based on the fact that both the adsorption tower and the bag filter realize the same flow of flue gas through solid barriers to achieve desulfurization and dust removal, and the pressure loss formula of the bag filter is:

[0044]

[0045] ΔP…pressure loss of adsorption unit (mmH2O);

[0046] ζ… resistance coefficient of adsorption unit;

[0047] ρ 工 ...Gas density at operating temperature and pressure (Kg / m 3 );

[0048] V…gas flow rate through the adsorption unit (m / s);

[0049] g…gravitational acceleration (m / s 2 );

[0050] The gas flow rate V through the adsorption tower can be calculated according to formula 1:

[0051]

[0052] According to the density calculation formula:

[0053]

[0054] ρ 工 ...Gas density at operating temperature and pressure (Kg / m 3 );

[0055] ρ 标 ...Gas density at standard state (Kg / m 3 );

[0056] T 测…the temperature of flue gas in the adsorption unit (℃);

[0057] P 测 …the flue gas pressure in the adsorption unit (Pa);

[0058] P0…local atmospheric pressure (Pa);

[0059] According to the direction of flue gas in the adsorption unit, the pressure loss ΔP of flue gas in the adsorption unit is the difference between the inlet pressure of the adsorption unit and the outlet pressure of the adsorption unit, that is:

[0060]

[0061] P1…pressure of flue gas at the inlet of adsorption unit (Pa);

[0062] P2…pressure of flue gas at the outlet of adsorption unit (Pa);

[0063] ΔP…pressure loss of adsorption unit (mmH2O);

[0064] Substituting Formula 4 and Formula 3 into Formula 2, we get:

[0065]

[0066] Combination Figure 1 (Flow chart of flue gas balance control process of adsorption tower), it can be seen that the flow rate V of flue gas passing through the adsorption unit is pre-calculated in formula 5, and other parameters can be obtained by looking up the table or setting up an online detection device, except for the resistance coefficient ζ of the adsorption unit. The manufacture, construction and assembly of each adsorption unit will have more or less deviations. In this way, the actual resistance coefficient of each adsorption unit is biased. Therefore, it is necessary to carry out actual measurement and calibration before the normal operation of the project (i.e., the debugging stage) to calculate the actual resistance coefficient ζ of each adsorption unit.

[0067] The specific method for determining the resistance coefficient ζ is as follows:

[0068] Fill each adsorption unit of the adsorption tower with activated coke and operate it as in normal production; start the booster fan 1 and control the air volume to the rated air volume of a single adsorption unit. 单 To indicate; close the inlet and outlet valves of other adsorption towers in the series, and open all the inlet and outlet valves of only one adsorption tower. When the operation is stable, record the current processing air volume, inlet and outlet pressures, transition air chamber pressure and temperature of the adsorption tower;

[0069] According to the continuous and stable operation characteristics of flue gas and the relationship between air volume and wind speed:

[0070] Q 单 =S×V (Formula 6)

[0071] Q 单 ...air volume passing through the adsorption unit per unit time (m 3 / h);

[0072] S…The cross-sectional area of ​​the flue gas passing through the activated coke in the adsorption unit at the same time (m 2 );

[0073] V…flow rate of flue gas passing through the adsorption unit (m / h);

[0074] According to Formula 5 and Formula 6, we can get the formula of measured resistance coefficient ζ:

[0075]

[0076] Right now:

[0077]

[0078] Repeat the above process and measure the actual resistance coefficient ζ for each adsorption unit of the adsorption tower one by one; write the measured resistance coefficient ζ into the corresponding formula 5. For example, the gas flow rate of the first adsorption unit is:

[0079] Combination Figure 1 (Flow chart of adsorption tower flue gas balance control process), then:

[0080] P 11 …pressure at the inlet of adsorption unit No. 1 (corresponding to equipment PT-11) (Pa);

[0081] P 12 …pressure at the outlet of adsorption unit No. 1 (corresponding to equipment PT-12) (Pa);

[0082] P 13 …pressure of transition chamber of adsorption unit No. 1 (corresponding equipment PT-13) (Pa);

[0083] T 11 …Temperature of transition chamber of adsorption unit No. 1 (corresponding equipment TE-11) (℃);

[0084] ζ1… Resistance coefficient of adsorption unit No. 1 (the above-mentioned coefficient has been measured);

[0085] P0…local standard atmospheric pressure (generally 101325) (Pa);

[0086] ρ 标 ...The density of smoke under standard conditions (generally 1.29) (Kg / m 3 );

[0087] g…Local gravity acceleration (usually 9.8) (m / s 2 );

[0088] Therefore, the online real-time flue gas flow rate of each adsorption unit can be obtained by calculation in the PLC system XIC11 (or DCS system), and various functional operations can be completed in the PLC system XIC11.

[0089] First, compare the flue gas flow rate of each adsorption unit with the designed rated flow rate in the adsorption unit. If the flow rate in that adsorption unit is greater than the designed rated value, an alarm will be issued on the main control screen.

[0090] Second, sort the flue gas flow rates of each adsorption unit, remove a maximum value and a minimum value, and take the remaining average value (another method is to sort the flue gas flow rates of the adsorption units, make differences between adjacent values, and if the difference is greater than one tenth of the design rated flow rate, remove the value far from the average value. The value will be recorded in the alarm table. If it does not appear, all values ​​are considered valid and the average value is calculated). This is used as the target value of the flow rate of each adsorption unit. The sampling period of this step should be greater than the time the flue gas stays in the adsorption unit; third, in each adsorption unit, the target value calculated in the second step is used as the set value of the PID adjustment of the outlet control valve of this adsorption unit. This adsorption unit calculates the flow rate in real time as the feedback value of the PID adjustment of the outlet control valve. Generally, the stable zone is ±5 of the set value to achieve automatic adjustment of the PID of the outlet control valve. This step is real-time.

[0091] Thereby, each adsorption unit is adjusted around a target value in each sampling cycle, and the target value of the next sampling cycle changes with the fluctuation of flue gas volume to be treated. It has a certain degree of adaptability and truly realizes automatic control of flue gas balance in each adsorption unit of the adsorption tower.

[0092] Example

[0093] The adsorption tower of the embodiment of the present invention is composed of four adsorption units. It includes: a gas flow meter FE-10 and a flow transmitter FT-10 set on the outlet main pipe of the booster fan 1, which realizes air volume regulation by controlling the frequency converter 2 of the booster fan 1. For the present invention, it is mainly used for initial calibration, and secondly, the resistance coefficient of each adsorption unit of the adsorption tower is corrected online. Figure 1 As shown in the figure, the adsorption tower is composed of multiple adsorption units. The flue gas is distributed to the corresponding number of adsorption units after passing through the main pipe from the booster fan 1. The first adsorption unit 3 is taken as an example to describe the direction of the flue gas entering the adsorption unit and the setting of the measuring points (such as Figure 2As shown), a pressure transmitter PT-11 for detecting the inlet pressure of the adsorption unit is arranged at the branch pipe entering the air inlet chamber 8. The flue gas is divided from the air inlet chamber 8 into two directions, left and right, through the side grid plate 12 of the air inlet of the first coke bed 10, and enters the first coke bed 10 to start the first-level adsorption. The flue gas passes through the side grid plate 12 of the air outlet of the first coke bed 10 and enters the transition air chamber 13. A flue gas temperature detection thermistor TE-11 and a pressure detection pressure transmitter PT-13 are arranged in the transition air chamber 13. The flue gas enters the second coke bed 11 from the transition air chamber 13 through the side grid plate 12 of the air inlet of the second coke bed 11. The flue gas after preliminary purification contacts with the regenerated active coke layer again to complete the secondary adsorption. The purified flue gas enters the air outlet chamber 9 through the side grid plate 12 of the air outlet of the second coke bed 11, and is merged into the main pipe after branch pipe and sent to the chimney 7 for discharge. A pressure transmitter PT-12 for detecting the outlet pressure of the adsorption unit is provided at the connection between the gas outlet chamber 9 and the branch pipe, and an electric butterfly valve HV / HZ-11 is provided on the branch pipe to regulate the circulating flue gas in the adsorption unit.

[0094] The detection parameters in the above equipment table are all sent to the PLC system XIC11 (or DCS system). At the beginning of the project or after the plant is shut down for overhaul, the resistance coefficient ζ of each adsorption unit is measured. Now take the first adsorption unit as an example, the specific steps are as follows:

[0095] Each adsorption unit of the adsorption tower is filled with activated coke, and the activated coke is put into operation as in normal production; the booster fan 1 is put into operation, and the air volume is controlled at the rated operating air volume of a single adsorption unit, and the Q 单 To indicate that the inlet and outlet valves of other adsorption units of the adsorption tower are all closed, and only the inlet and outlet valves of the first adsorption tower are all opened. The speed of the booster fan 1 is adjusted by the inverter 2, so that the air volume Q of the gas flow meter FE-10 at the outlet of the booster fan 1 is 10 =Q 单 When the operation is stable, record the current air volume, inlet and outlet pressures, transition chamber pressure and temperature of the adsorption tower;

[0096] According to formula 7, the resistance coefficient ζ1 of the first adsorption unit can be measured, and then:

[0097]

[0098] Q 单 ...air volume passing through the adsorption unit per unit time (m 3 / h);

[0099] S1…Effective area of ​​the grille plate on the air inlet side of the first coke bed in the first adsorption unit (m 2 );

[0100] P 11 …pressure at the inlet of adsorption unit No. 1 PT-11 (Pa);

[0101] P 12 …The pressure at the outlet of adsorption unit No. 1 is PT-12 (Pa);

[0102] P 13 …The pressure of the transition chamber of adsorption unit No. 1 is PT-13 (Pa);

[0103] T 11 …Temperature of transition chamber of adsorption unit No. 1 TE-11 (℃);

[0104] P0…local standard atmospheric pressure (generally 101325) (Pa);

[0105] ρ 标 ...The density of smoke under standard conditions (generally 1.29) (Kg / m 3 );

[0106] g…Local gravity acceleration (usually 9.8) (m / s 2 );

[0107] According to the above steps, the resistance coefficients ζ2 / ζ3 / ζ4 of the second adsorption unit 4, the third adsorption unit 5, and the fourth adsorption unit 6 are measured respectively, and the resistance coefficients of each adsorption unit are measured. The resistance coefficients of each adsorption unit are assigned to the flow rate calculation formula 5 corresponding to the PLC system XIC11 (or DCS system), and then:

[0108] In the above formula, x is the corresponding adsorption unit number;

[0109] Each detection parameter of the adsorption unit is calculated in the PLC system XIC11 (or DCS system) to obtain the online real-time flue gas flow rate of each adsorption unit, and complete various functional operations in the PLC system XIC11. First, determine whether the flue gas flow rate of the unit is normal, and if it is abnormal, an alarm will be issued on the main control screen;

[0110] Second, according to the time that the flue gas stays in the adsorption unit, the large sampling period of the overall flue gas balance control of the adsorption tower is set, which is generally greater than or equal to the time that the flue gas stays in the adsorption unit; by comparing and judging whether the data of each adsorption unit in the sampling period is valid, the average value is calculated using the valid data as the target value for the next period;

[0111] Third, in each adsorption unit, the target value calculated in the second step is used as the set value of the outlet regulating valve PID adjustment of each adsorption unit. Each adsorption unit calculates the flow rate in real time as the feedback value of the outlet regulating valve PID adjustment. The general stable zone is ±5 of the set value, realizing automatic adjustment of the outlet regulating valve PID. This step is real-time.

[0112] Thereby, the flue gas flow rate of each adsorption unit is adjusted around a target value in each large sampling cycle, and the target value of the next sampling cycle changes according to the fluctuation of the flue gas volume to be processed. It has a certain degree of adaptability and truly realizes the automatic control of the flue gas balance of each adsorption unit of the adsorption tower.

[0113] The automatic control device of the flue gas balance system of the activated coke adsorption tower of the present invention is not affected by the steps of component processing, manufacturing, assembly, welding, etc. of each adsorption unit, and realizes the measurement of the resistance coefficient ζ of each adsorption unit under actual production conditions; the flow rate in the adsorption unit is calculated based on relevant data, and no flow meter is required, which occupies a small area, requires less investment, and has a wider scope of application (new construction or renovation of old projects); the flue gas flow rate in each adsorption unit is the same (within the stable zone), and the adsorption tower is adaptive to the amount of flue gas to be treated. The equipment for setting the measurement points of each adsorption unit is shown in Table 1:

[0114] Table 1

[0115]

[0116]

Claims

1. An automatic control device for flue gas balance system of activated coke adsorption tower, characterized in that It includes a gas flow meter and flow transmitter installed on the booster fan outlet main pipe, a pressure transmitter installed on the inlet branch pipe of each adsorption unit air inlet chamber, a pressure transmitter and a thermal resistor installed on the transition air chamber of each adsorption unit, a pressure transmitter installed on the outlet branch pipe of each adsorption unit air outlet chamber, and an electric butterfly valve installed on the outlet branch pipe of each adsorption unit air outlet chamber. The pressure transmitters, thermal resistors and electric butterfly valves at different positions of each adsorption unit are all connected to the PLC system. The PLC system measures the resistance coefficient ζ of each adsorption unit. By measuring the air volume, inlet and outlet pressures, transition chamber pressure and temperature of the adsorption tower, the resistance coefficient ζ1 of the first adsorption unit is measured according to Formula 7, and the result is: Q 单 ...air volume passing through the adsorption unit per unit time (m 3 / h); S1…Effective area of ​​the grille plate on the air inlet side of the first coke bed in the first adsorption unit (m 2 ); P 11 …pressure at the inlet of adsorption unit No. 1 (Pa); P 12 …pressure at the outlet of adsorption unit No. 1 (Pa); P 13 …pressure of transition chamber of adsorption unit No. 1 (Pa); T 11 …Temperature of transition chamber of adsorption unit No. 1 (℃); P0…local standard atmospheric pressure, generally 101325 (Pa); ρ 标 ...The density of smoke under standard conditions is generally 1.29 (Kg / m 3 ); g…Local gravity acceleration, generally 9.8 (m / s 2 ); According to the above steps, the resistance coefficients of the second, third and fourth adsorption units ζ2 / ζ3 / ζ4 are measured respectively, and the resistance coefficients of each adsorption unit are determined. The resistance coefficients of each adsorption unit are assigned to the flow rate calculation formula 5 corresponding to the PLC, and then: Where x is the corresponding adsorption unit number, Therefore, the online real-time flue gas flow rate of each adsorption unit can be obtained through calculation in the PLC system, and various functional operations can be completed in the PLC system XIC11. First, compare the flue gas flow rate of each adsorption unit with the designed rated flow rate in the adsorption unit. If the flow rate in any adsorption unit is greater than the designed rated value, an alarm will be issued on the main control screen. Second, sort the flue gas flow rates of each adsorption unit, remove the maximum value and the minimum value, and take the remaining average value as the target value of the flow rate of each adsorption unit. The sampling period of this step should be greater than the time the flue gas stays in the adsorption unit. Third, in each adsorption unit, the target value calculated in the second step is used as the set value of the electric butterfly valve PID adjustment of this adsorption unit. This adsorption unit calculates the flow rate in real time as the feedback value of the electric butterfly valve PID adjustment. The general stable zone is ±5 of the set value, realizing automatic adjustment of the electric butterfly valve PID. This step is real-time.

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