CN-121592827-B - Optimal control method and system for combustible gas recovery

CN121592827BCN 121592827 BCN121592827 BCN 121592827BCN-121592827-B

Abstract

The invention belongs to the field of smelting gas recovery, and particularly relates to an optimization control method and system for combustible gas recovery, wherein the method is used for calculating the average secondary combustion coefficient of each time interval in real time by dividing a smelting process into N measuring time intervals; setting M target smelting time partitions and weights thereof, establishing a dynamic target value sequence, adjusting the initial fan rotation speed through multiple iteration furnace times, stepping down when the actual measurement coefficient is larger than the target value, introducing a thermal imager and a micro differential pressure instrument to monitor smoke escape, establishing a smoke generation rate statistics and tolerance threshold judgment mechanism, triggering the rotation speed retrospective adjustment, and finally minimizing the average secondary combustion coefficient in each time interval to generate an optimal fan rotation speed model. The invention realizes the maximum improvement of the heat value of the gas and the recovery quantity of the carbon monoxide on the premise of preventing the smoke at the furnace mouth.

Inventors

GONG YI
CHEN DELIANG
LIU CAIMING
Xie Houjin
SUN LINSEN

Assignees

南京恒瑞环保科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (9)

1. The optimizing control method for the combustible gas recovery is characterized by comprising the following steps: Setting N measuring time periods, and calculating a real-time interval average secondary combustion coefficient sequence in the N measuring time periods in the smelting process; setting M target smelting time partitions in the same smelting process, setting secondary combustion target values, and obtaining a secondary combustion target value sequence of each target smelting time partition, wherein ; Setting a tolerance value of the initial fan rotating speed and the smoking occurrence rate, responding to the initial fan rotating speed, and determining the corresponding relation between the real-time interval average secondary combustion coefficient sequence and M target smelting time partitions according to the measured time period corresponding to the real-time interval average secondary combustion coefficient sequence and the time stamp relation of the target smelting time partitions; According to the corresponding relation between the real-time interval average secondary combustion coefficient sequence and the M target smelting time partitions, if the real-time interval average secondary combustion coefficient of any one of the N measuring time periods is larger than the secondary combustion target value corresponding to the corresponding target smelting time partition, according to a preset iteration heat, under the condition of the smoke generation rate tolerance value, taking the secondary combustion target value as a target iteration direction and combining a rotating speed backtracking mechanism, carrying out the deceleration adjustment of the preset stepping length on the rotating speed of the fan in the measuring time period under each iteration heat until the interval average secondary combustion coefficient of the measuring time period reaches the minimum value or the deviation of the target value corresponding to the M target smelting time partitions meets a preset deviation threshold; Setting a furnace mouth micro-pressure difference less than or equal to 0 as a smoke emission constraint threshold, judging that smoke overflows when the furnace mouth micro-pressure difference is detected to be more than 0, stopping the speed reduction adjustment of the measurement time period, establishing a mapping relation between a fan rotating speed and an air supply pressure, collecting the current pressure of the air storage cabinet in real time, calculating the minimum fan rotating speed meeting the air supply pressure requirement based on the mapping relation between the fan rotating speed and the air supply pressure, determining that the lower limit of the fan rotating speed adjustment is a larger value of the minimum fan rotating speed and the critical fan rotating speed avoiding the furnace mouth micro-pressure difference to be more than 0, ensuring that the air supply pressure corresponding to the fan rotating speed at any time point is always more than the current pressure of the air storage cabinet, and enabling the interval average secondary combustion coefficient corresponding to the measurement time period to be minimum; the rotational speed backtracking mechanism comprises: Obtaining occurrence rate of smoking The corresponding fan rotating speed when the smoke occurrence rate tolerance value D is larger than or equal to the preset smoke occurrence rate tolerance value D is used as a measurement time period Is multiplied by a preset step-down length to correspond to the time when the tolerance value of the smoking occurrence rate is not satisfied For measuring time periods Backtracking a step value of the first starting rotational speed; obtaining a measurement time period by adding the first initial rotation speed retrospective stepping value to the search initial value And in response to the first back-off fan speed value, repeating at least one measurement period of time under the current iteration heat The corresponding real-time interval average secondary combustion coefficient is larger than the secondary combustion target value corresponding to the target smelting time partition and the current measurement time period is detected by a configured thermal imager or a micro differential pressure instrument In the iterative heat process corresponding to the overflow of the flue gas, the corresponding process under the rotating speed value of the first back fan is judged If the smoke generation rate is smaller than the preset smoke generation rate tolerance value D, taking the first back fan rotating speed value and the corresponding real-time combustion coefficient as a measurement time period Is a local optimum rotational speed and a local optimum interval average secondary combustion coefficient; if the smoke occurrence rate tolerance value D is greater than or equal to the smoke occurrence rate tolerance value D, the first reversing fan rotating speed value is taken as a searching starting value, and the first starting rotating speed backtracking stepping value is multiplied by the corresponding first reversing fan rotating speed value And adding the first back-off fan rotating speed value to obtain a second back-off fan rotating speed value, and repeating the iterative and discriminating processes corresponding to the first back-off fan rotating speed value, if so If the smoke occurrence rate is still greater than or equal to the smoke occurrence rate tolerance value D, repeating the processes of acquiring, iterating and judging the corresponding second back fan rotating speed value to carry out fan rotating speed backtracking iteration until the smoke occurrence rate tolerance value D is met for the first time, recording the current backtracking times, the real-time fan rotating speed value corresponding to the smoke occurrence rate tolerance value D and the real-time interval average secondary combustion coefficient as the measurement time period And the average secondary combustion coefficient of the corresponding local optimal interval.
2. The optimal control method for combustible gas recovery of claim 1, further comprising: repeating the measuring period Iterative heat process of corresponding interval average secondary combustion coefficient, for all measurement time periods Carrying out the same heat iteration on the real-time interval average secondary combustion coefficient of the N measuring time periods, and simultaneously, when the smoke occurrence tolerance value is met, enabling the real-time interval average secondary combustion coefficient of all the measuring time periods in the N measuring time periods to reach the minimum or enabling the deviation of target values corresponding to M target smelting time partitions to meet a preset deviation threshold value, and combining a combustion coefficient-fan rotating speed mapping table to obtain fan rotating speed parameters under the condition that the real-time interval average secondary combustion coefficient in the N measuring time periods meets the condition, and packaging the fan rotating speed parameters into a fan rotating speed model; Indicating the nth measurement period in the smelting process corresponding to the b iteration heat.
3. The optimizing control method for combustible gas recovery according to claim 2, wherein the acquiring process of the real-time interval average secondary combustion coefficient sequence includes: Partitioning the smelting process of each iterative heat corresponding to the whole time length based on the set N measuring time periods to obtain a measuring time period sequence; The method comprises the steps of installing a carbon monoxide and carbon dioxide analyzer in a flue of a converter, and measuring the concentration of carbon monoxide and the concentration of carbon dioxide in each measuring time period in the measuring time period sequence to obtain a measuring result of each measuring time period; based on the measurement result of each measurement time period of each iteration heat, calculating to obtain the corresponding measurement time period under each iteration heat And (5) real-time interval average secondary combustion coefficient.
4. The optimal control method for combustible gas recovery according to claim 3, wherein the step-down adjustment of the fan rotation speed in the measurement period for each iteration heat by a preset step length includes: when at least one measuring time period exists in N measuring time periods of the current iteration heat When the average secondary combustion coefficient of the corresponding real-time interval is larger than the secondary combustion target value of the corresponding target smelting time partition and no smoke overflows from the converter in the current measurement time period detected by the configured thermal imager or micro differential pressure instrument or manual observation, the average secondary combustion coefficient of the corresponding real-time interval is the same in the next furnace in the same measurement time period Subtracting a preset step-down length from the fan rotating speed corresponding to the current iteration heat as the same measurement time period of the next iteration heat The fan operation is carried out at the first fan rotating speed; Synchronously measuring the measurement time period of the corresponding iterative heat under the fan running operation of the first fan rotating speed response And (3) continuously repeating the rotation speed adjustment of the remaining iterative heat fan until the preset iterative heat B or the interval average secondary combustion coefficient is minimum or the deviation of target values corresponding to M target smelting time partitions meets a preset deviation threshold.
5. The optimal control method for combustible gas recovery according to claim 4, wherein a speed reduction adjustment of a preset step length is performed on a fan speed in the measurement period for each iteration heat, further comprising: when at least one measuring time period exists in N measuring time periods of the current iteration heat When the corresponding real-time interval average secondary combustion coefficient is larger than the secondary combustion target value corresponding to the target smelting time partition and smoke overflow in the current measurement time period is detected through a configured thermal imager or a micro differential pressure instrument or manual observation, the same measurement time period of the next iteration furnace is carried out Setting the rotating speed of the fan corresponding to the current iteration heat as the rotating speed of the second fan in the same measuring time period of the remaining iteration heat, namely setting the preset stepping deceleration length to 0, and carrying out fan operation; Simultaneously, synchronously measuring each same measurement time period under all iteration heats when the remaining iteration heats are carried out under the condition of responding to the rotating speed of the second fan And (3) measuring the real-time interval average secondary combustion coefficient and the flue gas overflow until reaching the minimum preset iteration furnace number or interval average secondary combustion coefficient or the deviation of target values corresponding to M target smelting time partitions meets a preset deviation threshold.
6. The optimal control method for combustible gas recovery according to claim 5, wherein a speed reduction adjustment of a preset step length is performed on a fan speed in the measurement period for each iteration heat, further comprising: counting the same measurement time period in the total iteration heat of the actual generation The actual overflow iteration number C corresponding to the fume overflow is calculated according to the ratio of the actual overflow iteration number C to the total iteration heat actually occurring, and the measurement time period is calculated Occurrence of smoke in the lower part ; When (when) When the current iteration heat corresponding to the fan speed is less than the preset smoke occurrence tolerance value D, judging that the current iteration heat corresponding to the fan speed is the upper limit of the smoke speed, and taking the current speed as a measurement time period Corresponding local optimal rotating speed, and the real-time combustion coefficient corresponding to the current local optimal rotating speed is the measurement time period And the average secondary combustion coefficient of the corresponding local optimal interval.
7. The optimal control method for combustible gas recovery according to claim 6, wherein a speed reduction adjustment of a preset step length is performed on a fan speed in the measurement period for each iteration heat, further comprising: When (when) When the smoke occurrence rate tolerance value D is larger than or equal to the preset smoke occurrence rate tolerance value D, judging that the rotating speed of the fan corresponding to the current iteration heat is smaller than the upper limit of the smoke rotating speed, triggering a preset rotating speed backtracking mechanism until the measuring time period Corresponding to The method comprises the steps that when the smoke occurrence rate tolerance value is smaller than a preset smoke occurrence rate tolerance value D, the fan rotating speed corresponding to the smoke occurrence rate tolerance value D which is met at present is taken as a local backtracking optimal rotating speed corresponding to a measurement time period, and an interval average secondary combustion coefficient corresponding to the local backtracking optimal rotating speed is taken as a local optimal interval average secondary combustion coefficient corresponding to the measurement time period; And repeating the searching process of the local optimal rotating speed and the local optimal interval average secondary combustion coefficient corresponding to the measuring time periods, searching the N measuring time periods for the synchronous local optimal rotating speed and the local optimal interval average secondary combustion coefficient, and obtaining the local optimal rotating speed and the local optimal interval average secondary combustion coefficient sequence corresponding to each measuring time period.
8. The optimal control method for combustible gas recovery according to claim 7, wherein the process of detecting the overflow of the flue gas in the current measurement period by the configured thermal imager or micro differential pressure instrument or manual observation comprises: acquiring infrared thermal imaging temperature field distribution or flue gas overflow data of a converter mouth region through a configured thermal imager, and/or synchronously acquiring micro differential pressure of the converter mouth region through a micro differential pressure instrument; And judging that the flue gas escapes from the converter mouth when the abnormal flue gas plume is identified and the micro differential pressure is larger than a preset micro differential pressure threshold value based on the temperature field distribution data or the flue gas overflow data and the micro differential pressure.
9. An optimizing control system for recycling combustible gas, which is used for realizing the optimizing control method for recycling the combustible gas according to any one of claims 1-8, and is characterized by comprising a first partition module, a second partition module, a mapping module, a rotating speed adjusting module and a global optimizing module; The first partitioning module is used for setting N measuring time periods and calculating a real-time interval average secondary combustion coefficient sequence in the N measuring time periods in the smelting process; The second partition module is used for setting M target smelting time partitions and secondary combustion target values in the same smelting process simultaneously to obtain a secondary combustion target value sequence of each target smelting time partition, wherein ; The mapping module is used for setting an initial fan rotating speed and a smoke generation rate tolerance value, responding to the initial fan rotating speed, and determining the corresponding relation between the real-time interval average secondary combustion coefficient sequence and M target smelting time partitions according to the measured time interval corresponding to the real-time interval average secondary combustion coefficient sequence and the timestamp relation of the target smelting time partitions; The rotating speed adjusting module is used for carrying out the speed reducing adjustment of a preset stepping length on the rotating speed of the fan in each iteration furnace time by taking the secondary combustion target value as a target iteration direction and combining a rotating speed backtracking mechanism under the condition of the smoke generating rate tolerance value according to the preset iteration furnace time if the real-time interval average secondary combustion coefficient of any one of the N measurement time periods is larger than the secondary combustion target value corresponding to the corresponding target smelting time zone, and the rotating speed of the fan in the measurement time period is adjusted until the interval average secondary combustion coefficient of the measurement time period reaches the minimum value or the deviation of the target value corresponding to the M target smelting time zones meets a preset deviation threshold value; The global optimization module is used for repeating the measurement time period Iterative heat process of corresponding interval average secondary combustion coefficient, for all measurement time periods Carrying out the same heat iteration on the real-time interval average secondary combustion coefficient of the N measuring time periods, and simultaneously, when the smoke occurrence tolerance value is met, enabling the real-time interval average secondary combustion coefficient of all the measuring time periods in the N measuring time periods to reach the minimum or enabling the deviation of target values corresponding to M target smelting time partitions to meet a preset deviation threshold value, and combining a combustion coefficient-fan rotating speed mapping table to obtain fan rotating speed parameters under the condition that the real-time interval average secondary combustion coefficient in the N measuring time periods meets the condition, and packaging the fan rotating speed parameters into a fan rotating speed model; Indicating the nth measurement period in the smelting process corresponding to the b iteration heat.

Description

Optimal control method and system for combustible gas recovery Technical Field The invention belongs to the field of smelting gas recovery, and particularly relates to an optimization control method and system for combustible gas recovery. Background In the converter gas recovery process, a core technical contradiction always exists that in order to recover the carbon monoxide gas with high concentration and high heat value, the micro-differential pressure of a furnace mouth is stably controlled in a micro-positive pressure interval through the traction force generated by a fan so as to effectively isolate air from being inhaled, and precious CO is prevented from being in contact with oxygen to generate secondary combustion and being oxidized into carbon dioxide with low heat value. However, the existing control strategy mostly depends on a fan rotating speed mode with fixed or few preset gears, and the rough control mode can not respond to the instantaneous and changeable gas production condition in the smelting process in real time, so that double dilemma is caused, on one hand, the fan pumping force is excessively rich in most time periods, excessive air is sucked though smoking is prevented, the avoided CO secondary combustion loss is caused, the gas calorific value is obviously reduced, on the other hand, the furnace mouth smoke overflow is possibly caused due to relatively insufficient pumping force in a specific smelting stage, serious safety and environmental hidden trouble are caused, and the one-cut control mode can not realize optimal balance on two key targets of safety smoke prevention and calorific value maximization all the time, so that considerable economic benefit loss is caused, and on the other hand, the fan rotating speed can be dynamically and accurately regulated, so that the secondary combustion is furthest restrained and the gas recovery calorific value is improved on the premise of absolute guarantee of safety production. The problems of the prior art are that the prior art only considers fan rotating speed setting from a single-point steady-state working condition or performs sectional control based on a rough time period, but cannot perform accurate balanced configuration on the furnace mouth suction air quantity and the smoke suction force according to the actual gas generation dynamics of the smelting process so as to realize the dual purposes of safe explosion suppression and heat value improvement, and therefore, the invention provides an optimal control method and system for combustible gas recovery. Disclosure of Invention Aiming at the defects of the prior art, the invention provides an optimal control method and system for recycling combustible gas, the method comprises the steps of dividing a smelting process into N measurement time periods, calculating average secondary combustion coefficients of all time periods in real time, setting M target smelting time partitions and weights thereof, establishing a dynamic target value sequence, adjusting the actual measurement coefficients to be larger than the target values according to the initial fan rotating speed through multiple iteration furnace times, monitoring the escape of flue gas by introducing a thermal imager and a micro differential pressure instrument, establishing a smoke occurrence rate statistics and tolerance threshold judgment mechanism, triggering the rotating speed backtracking adjustment, and finally minimizing the average secondary combustion coefficients of all time periods under the safety constraint to generate an optimal fan rotating speed model. The invention realizes the maximum improvement of the heat value of the gas and the recovery quantity of the carbon monoxide on the premise of preventing the smoke at the furnace mouth. In order to achieve the above purpose, the present invention provides the following technical solutions: an optimal control method for combustible gas recovery, comprising: Setting N measuring time periods, and calculating a real-time interval average secondary combustion coefficient sequence in the N measuring time periods in the smelting process; setting M target smelting time partitions in the same smelting process, setting secondary combustion target values, and obtaining a secondary combustion target value sequence of each target smelting time partition, wherein ; Setting a tolerance value of the initial fan rotating speed and the smoking occurrence rate, responding to the initial fan rotating speed, and determining the corresponding relation between the real-time interval average secondary combustion coefficient sequence and M target smelting time partitions according to the measured time period corresponding to the real-time interval average secondary combustion coefficient sequence and the time stamp relation of the target smelting time partitions; According to the corresponding relation between the real-time interval average secondary combustion coefficient sequence a