阅读说明：本技术 一种燃尽风门开度控制方法及其存储介质 (Method for controlling opening degree of burnout air door and storage medium thereof ) 是由 赵鹏 王小华 陈宝康 陈敏 梅振锋 薛晓垒 彭小敏 俞胜捷 刘瑞鹏 丁奕文 朱晋 于 2021-08-04 设计创作，主要内容包括：本发明提供一种燃尽风门开度控制方法及其存储介质,包括：采集锅炉的负荷值；根据锅炉的负荷值采集相对应的运行氧量实际值,预设锅炉的运行氧量控制阈值,根据所述运行氧量实际值与所述运行氧量控制阈值计算得到锅炉的运行氧量偏差值；根据锅炉的运行氧量偏差值计算修正得到控制回路输出值,经过处理输出燃尽风门开度指令,所述燃尽风门开度指令用于控制燃尽风门开度大小,以获得相对应的燃尽风门开度值；本发明提供一种燃尽风门开度控制方法及其存储介质,锅炉在升降负荷过程偏离稳态运行工况情况下,能够提高煤粉燃尽率,并降低NOx生成浓度。(The invention provides a burnout air door opening degree control method and a storage medium thereof, wherein the burnout air door opening degree control method comprises the following steps: collecting a load value of a boiler; acquiring a corresponding running oxygen amount actual value according to a load value of the boiler, presetting a running oxygen amount control threshold value of the boiler, and calculating to obtain a running oxygen amount deviation value of the boiler according to the running oxygen amount actual value and the running oxygen amount control threshold value; calculating and correcting according to the running oxygen deviation value of the boiler to obtain a control loop output value, and outputting a burnout air door opening instruction after processing, wherein the burnout air door opening instruction is used for controlling the opening size of the burnout air door to obtain a corresponding burnout air door opening value; the invention provides a method for controlling the opening of a burnout air door and a storage medium thereof, which can improve the burnout rate of pulverized coal and reduce the generation concentration of NOx under the condition that a boiler deviates from a steady-state operation working condition in the process of lifting load.)

1. A burnout damper opening degree control method is characterized by comprising the following steps:

collecting a load value of a boiler;

acquiring a corresponding running oxygen amount actual value according to a load value of the boiler, presetting a running oxygen amount control threshold value of the boiler, and calculating to obtain a running oxygen amount deviation value of the boiler according to the running oxygen amount actual value and the running oxygen amount control threshold value;

and calculating and correcting according to the load value of the boiler and the running oxygen deviation value of the boiler to obtain a control loop output value, and outputting a burnout air door opening instruction after processing, wherein the burnout air door opening instruction is used for controlling the opening size of the burnout air door so as to obtain a corresponding burnout air door opening value.

2. The method for controlling the opening degree of a burnout damper according to claim 1, wherein the operating oxygen deviation value is calculated by the following formula:

C＝(A-B)×100％

wherein A is the actual value of the operation oxygen amount, B is the control threshold value of the operation oxygen amount, and C is the deviation value of the operation oxygen amount.

3. The method of controlling a burnout damper opening according to claim 2, wherein the control loop output value is calculated by the following equation:

E＝D+C

wherein C is a burnout air door correction value corresponding to the running oxygen deviation value, D is a burnout air door opening value corresponding to the load value of the boiler, and E is a control loop output value.

4. The opening control method of the burnout damper according to claim 1, wherein the opening of the burnout damper is controlled by a burnout damper opening command, comprising the steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

when the actual value of the operating oxygen amount is lower than the operating oxygen amount control threshold value of the boiler, calculating according to the operating oxygen amount deviation value of the boiler to obtain a corresponding burnout air door correction value as a negative value;

presetting a correction value range of the deviation adjustment dead zone of the operating oxygen amount, confirming that the output value of the control loop obtained by calculation and correction is not in the correction value range of the deviation adjustment dead zone of the operating oxygen amount, outputting an opening instruction of a burnout air door to be turned off, and controlling the opening of the burnout air door to be turned off to obtain a corresponding opening value of the burnout air door.

5. The opening control method of the burnout damper according to claim 1, wherein the opening of the burnout damper is controlled by a burnout damper opening command, comprising the steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

when the actual value of the operating oxygen amount is higher than the operating oxygen amount control threshold value of the boiler, calculating to obtain a corresponding opening correction value of the burnout air door as a positive value according to the operating oxygen amount deviation value of the boiler;

presetting a correction value range of the deviation adjustment dead zone of the operating oxygen amount, confirming that the output value of the control loop obtained by calculation and correction is not in the correction value range of the deviation adjustment dead zone of the operating oxygen amount, outputting an opening instruction of the burnout air door to be opened, and controlling the opening of the burnout air door to be opened to be large so as to obtain a corresponding opening value of the burnout air door.

6. The opening control method of the burnout damper according to claim 1, wherein the opening of the burnout damper is controlled by a burnout damper opening command, comprising the steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

calculating and correcting according to the running oxygen deviation value of the boiler to obtain a control loop output value;

presetting a range of a correction value of an operating oxygen deviation dead zone, confirming that the output value of the control loop obtained by calculation and correction is within the range of the correction value of the operating oxygen deviation dead zone, not outputting an opening instruction of a large burnout air door and simultaneously not outputting an opening instruction of a small burnout air door, and controlling the opening of the burnout air door not to be opened and closed so as to obtain the corresponding opening value of the burnout air door to be 0.

7. The burnout damper opening degree control method according to claim 1, further comprising: the method comprises the following steps of optimizing a NOx change data curve in the load change process of the coal-fired boiler, wherein the step of optimizing the NOx change data curve in the load change process of the coal-fired boiler comprises the following steps:

collecting N different load values and running oxygen amount deviation values corresponding to the N different load values in the process of changing the boiler load, collecting, calculating and correcting to obtain control loop output values corresponding to the N different load values and the running oxygen amount deviation values, obtaining corresponding N different opening values of the burn-out air doors through N different opening instructions of the burn-out air doors output by the N different control loop output values, and recording N optimal NOx concentration values corresponding to the N different opening values of the burn-out air doors;

and fitting the obtained N different load values, the operation oxygen amount deviation value, the N different burn-out air door opening degree values and the N optimal NOx concentration values through a DCS automatic control system to obtain a boiler load-burn-out air opening degree NOx change data curve.

8. A burnout damper opening degree control storage medium having stored thereon a computer program that causes an electronic device to execute a burnout damper opening degree control method according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of boilers, in particular to a method for controlling the opening of a burnout air door and a storage medium thereof.

Background

With the continuous improvement of the requirement on the AGC response rate of the domestic thermal power generating unit, the thermal power generating unit needs to frequently and quickly lift the load during operation. In order to ensure the load response rate, the coal feeding amount control has a large overshoot when the load changes, and when the thermal power generating unit receives a load increasing (decreasing) instruction, the coal feeding amount can rapidly and greatly increase (decrease), so that the operation oxygen amount is lower (higher) and deviates from the steady-state operation working condition. During load increase, the actual operation oxygen amount is low, so that the coal powder burnout rate is reduced, and the boiler thermal efficiency is reduced; when the load is reduced, the excessive air coefficient of the main combustion area is increased due to the fact that the actual operation oxygen amount is higher, the low-nitrogen combustion effect is reduced, and the NOx generation concentration is greatly increased.

At present, the study of the over-fire air opening degree by scholars at home and abroad mainly focuses on the influence of the over-fire air rate on the coal powder burnout property and the NOx generation concentration under the steady-state working condition. In practical application, according to NOx generation concentration and pulverized coal burnout conditions under various loads obtained by a combustion optimization adjustment test, an optimal burnout air opening degree is determined, a load-burnout air opening degree curve is formulated, the control value of the burnout air opening degree is determined by the load, and a corresponding burnout air opening degree is output under a certain load. The control method is suitable for the steady-state working condition, but under the unsteady-state working condition, the combustion state deviates from the steady-state working condition due to the coal quantity overshoot, the opening of the over-fire air is still not beneficial to the over-fire of the pulverized coal or the reduction of the NOx generation concentration according to the load change, and the obvious defect exists.

Disclosure of Invention

In order to solve the technical problems, the invention provides a control method of the opening of a burnout air door and a storage medium thereof, which can improve the burnout rate of pulverized coal and reduce the generation concentration of NOx under the condition that a boiler deviates from a steady-state operation working condition in the process of lifting load.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the invention provides a method for controlling the opening degree of a burnout air door, which comprises the following steps:

collecting a load value of a boiler;

acquiring a corresponding running oxygen amount actual value according to a load value of the boiler, presetting a running oxygen amount control threshold value of the boiler, and calculating to obtain a running oxygen amount deviation value of the boiler according to the running oxygen amount actual value and the running oxygen amount control threshold value;

and calculating and correcting according to the load value of the boiler and the running oxygen deviation value of the boiler to obtain a control loop output value, and outputting a burnout air door opening instruction after processing, wherein the burnout air door opening instruction is used for controlling the opening size of the burnout air door so as to obtain a corresponding burnout air door opening value.

The invention provides a method for controlling the opening of a burnout air door and a storage medium thereof, which can improve the burnout rate of pulverized coal and reduce the generation concentration of NOx under the condition that a boiler deviates from a steady-state operation working condition in the process of lifting load.

As a preferred technical scheme, the deviation value of the operating oxygen amount is calculated by the following formula:

C＝(A-B)×100％

wherein A is the actual value of the operation oxygen amount, B is the control threshold value of the operation oxygen amount, and C is the deviation value of the operation oxygen amount.

As a preferred technical solution, the control loop output value is calculated by the following formula:

E＝D+C

wherein C is a burnout air door correction value corresponding to the running oxygen deviation value, D is a burnout air door opening value corresponding to the load value of the boiler, and E is a control loop output value.

As a preferred technical scheme, the method for controlling the opening of the burnout air door through the opening instruction of the burnout air door comprises the following steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

when the actual value of the operating oxygen amount is lower than the operating oxygen amount control threshold value of the boiler, calculating according to the operating oxygen amount deviation value of the boiler to obtain a corresponding burnout air door correction value as a negative value;

presetting a correction value range of the deviation adjustment dead zone of the operating oxygen amount, confirming that the output value of the control loop obtained by calculation and correction is not in the correction value range of the deviation adjustment dead zone of the operating oxygen amount, outputting an opening instruction of a burnout air door to be turned off, and controlling the opening of the burnout air door to be turned off to obtain a corresponding opening value of the burnout air door.

As a preferred technical scheme, the method for controlling the opening of the burnout air door through the opening instruction of the burnout air door comprises the following steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

when the actual value of the operating oxygen amount is higher than the operating oxygen amount control threshold value of the boiler, calculating to obtain a corresponding opening correction value of the burnout air door as a positive value according to the operating oxygen amount deviation value of the boiler;

presetting a correction value range of the deviation adjustment dead zone of the operating oxygen amount, confirming that the output value of the control loop obtained by calculation and correction is not in the correction value range of the deviation adjustment dead zone of the operating oxygen amount, outputting an opening instruction of the burnout air door to be opened, and controlling the opening of the burnout air door to be opened to be large so as to obtain a corresponding opening value of the burnout air door.

As a preferred technical scheme, the method for controlling the opening of the burnout air door through the opening instruction of the burnout air door comprises the following steps of:

collecting a load value of a boiler;

acquiring an actual operating oxygen amount value corresponding to the load value of the boiler, presetting an operating oxygen amount control threshold value of the boiler, and calculating to obtain an operating oxygen amount deviation value of the boiler according to the actual operating oxygen amount value and the operating oxygen amount control threshold value;

calculating and correcting according to the running oxygen deviation value of the boiler to obtain a control loop output value;

presetting a range of a correction value of an operating oxygen deviation dead zone, confirming that the output value of the control loop obtained by calculation and correction is within the range of the correction value of the operating oxygen deviation dead zone, not outputting an opening instruction of a large burnout air door and simultaneously not outputting an opening instruction of a small burnout air door, and controlling the opening of the burnout air door not to be opened and closed so as to obtain the corresponding opening value of the burnout air door to be 0.

As a preferred technical solution, the method further comprises: the method comprises the following steps of optimizing a NOx change data curve in the load change process of the coal-fired boiler, wherein the step of optimizing the NOx change data curve in the load change process of the coal-fired boiler comprises the following steps:

collecting N different load values and running oxygen amount deviation values corresponding to the N different load values in the process of changing the boiler load, collecting, calculating and correcting to obtain control loop output values corresponding to the N different load values and the running oxygen amount deviation values, obtaining corresponding N different opening values of the burn-out air doors through N different opening instructions of the burn-out air doors output by the N different control loop output values, and recording N optimal NOx concentration values corresponding to the N different opening values of the burn-out air doors;

and fitting the obtained N different load values, the operation oxygen amount deviation value, the N different burn-out air door opening degree values and the N optimal NOx concentration values through a DCS automatic control system to obtain a boiler load-burn-out air opening degree NOx change data curve.

The present invention also provides a burnout damper opening degree control storage medium having stored thereon a computer program that causes an electronic device to execute the burnout damper opening degree control method according to any one of the above.

Drawings

FIG. 1 is a flow chart of a method of controlling the opening of a burnout damper;

FIG. 2 is a control curve for operating an oxygen deviation to adjust the opening of the burnout damper;

FIG. 3 is a graph of data showing the variation of NOx in boiler load versus overfire air opening (not optimized by the overfire air door opening control method of the present invention);

FIG. 4 is a graph of data showing changes in the boiler load versus the overfire air opening NOx (optimized by the method for controlling the opening of the overfire air door according to the present invention).

Detailed Description

No. 5 thermal power generating unit of a certain power plant is a 600MW four-corner tangential coal-fired unit, is provided with an upper group of over-fire air and a lower group of over-fire air, and four layers of over-fire air nozzles of each group can control NOx to be 200mg/m under the stable working condition of a 600 MW-210 MW full-load region³Within the unit, the low-nitrogen combustion effect is good, but when the load is reduced by 300 MW-210 MW, the running oxygen amount is greatly increased due to the coal amount overshoot, the NOx concentration is increased along with the running oxygen amount, huge running pressure is brought to a denitration system, and the change curve of the NOx concentration of the unit at the load reduction stage of 300 MW-210 MW is shown in FIG. 3.

As shown in FIG. 3, the curve of the variation data of the boiler load-burnout air opening degree NOx (which is not optimized by the control method of the burnout air opening degree) can find that the concentration of NOx is only 100mg/m before the load is reduced³On the left and right sides, descending the negativeDuring the load period, the oxygen amount rises rapidly, the low-nitrogen combustion effect is weakened, the NOx concentration rises greatly, and when the load is reduced to 220MW, the NOx concentration reaches 238mg/m³The problem that the concentration of NOx rapidly and greatly rises during the low-load reduction process occurs, so that the ammonia escape of a denitration system also greatly rises, the standard reaching performance of unit operation environment-friendly parameters is seriously influenced, and the air preheater is also seriously corroded.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 4, the set over-fire air control method is characterized in that two groups of eight layers of over-fire air nozzles are arranged in total along with load change, and at most six layers of over-fire air nozzles are opened in actual operation to ensure that the generation concentration of NOx is lower than 200mg/m under stable load³And the opening degree of the upper two layers of over-fire air is in a 5% opening state. In order to reduce the NOx generation concentration during load reduction, the control method of the burnout air door is adopted, a control loop for comprehensively controlling the opening degrees of the upper layer of burnout air by combining the opening degree value of the burnout air door corresponding to the load value of the boiler with the opening correction value of the burnout air door corresponding to the operating oxygen deviation value is added,

the method comprises the following steps that a load value of a boiler is collected by an overfire air opening control loop;

collecting a corresponding running oxygen amount actual value according to a load value of the boiler, presetting a running oxygen amount control threshold value of the boiler, calculating a running oxygen amount deviation value of the boiler according to the running oxygen amount actual value and the running oxygen amount control threshold value, and calculating the running oxygen amount deviation value through the following formula to obtain:

C＝(A-B)×100％

wherein A is an actual value of the operating oxygen amount, B is an operating oxygen amount control threshold value, and C is an operating oxygen amount deviation value;

when the actual value of the operating oxygen amount is higher than the control threshold value of the operating oxygen amount of the boiler, the output value of the control loop is calculated by the following formula:

E＝D+C

wherein C is a burnout air door opening correction value corresponding to the running oxygen deviation value, D is a burnout air door opening value corresponding to the load value of the boiler, and E is a control loop output value;

calculating to obtain a corresponding burnout air door opening correction value as a positive value according to the operating oxygen deviation value of the boiler, and adding the burnout air door opening correction value and the burnout air door opening value corresponding to the load value to obtain a control loop output value;

presetting a correction value range of an operating oxygen deviation regulation dead zone, confirming that the output value of a control loop obtained by calculation and correction is not in the correction value range of the operating oxygen deviation regulation dead zone, outputting a command of opening a large burnout air door, starting to control the opening of the upper two layers of burnout air doors when the operating oxygen deviation is more than 0.3%, and controlling the opening of the upper two layers of burnout air doors to be maximum when the operating oxygen deviation reaches 1.5% so as to obtain a corresponding burnout air door opening value of 35%.

The invention provides a method for controlling the opening degree of a burnout air door, which further comprises the following steps: the method comprises the following steps of optimizing a NOx change data curve in the load change process of the coal-fired boiler, wherein the step of optimizing the NOx change data curve in the load change process of the coal-fired boiler comprises the following steps:

collecting N different load values and running oxygen amount deviation values corresponding to the N different load values in the process of changing the boiler load, collecting, calculating and correcting to obtain control loop output values corresponding to the N different load values and the running oxygen amount deviation values, obtaining corresponding N different opening values of the burn-out air doors through N different opening instructions of the burn-out air doors output by the N different control loop output values, and recording N optimal NOx concentration values corresponding to the N different opening values of the burn-out air doors;

a curve of the change data of the boiler load-the opening degree of the over-fire air NOx obtained by fitting the N different load values, the deviation value of the operating oxygen amount, the N different opening degrees of the over-fire air doors, and the N optimal NOx concentration values by the DCS automatic control system is shown in fig. 4.

As shown in FIG. 4, a curve of the variation data of the boiler load-burnout air opening degree NOx (optimized by the control method of the burnout air door opening degree) can be observed from the graph, when the deviation of the operating oxygen amount exceeds 0.3%, the upper two layers of burnout air doors are gradually opened, when the deviation of the operating oxygen amount reaches 1.5%, the maximum opening degree during the whole load reduction period is 35%, and the maximum NOx concentration is 184mg/m³The maximum value is 54mg/m lower than the initial working condition³The average NOx concentration during load reduction is reduced by 32mg/m compared with the initial working condition³The effect of reducing the concentration of NOx is very obvious.

It is to be understood that the present invention has been described with reference to certain embodiments, and that various changes in the features and embodiments, or equivalent substitutions may be made therein by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all modifications and equivalents falling within the scope of the appended claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.