阅读说明：本技术 变负载过程中的氮氧化物控制方法、装置及煤燃烧系统 (Nitrogen oxide control method and device in variable load process and coal combustion system ) 是由 刘智勇 郑双清 于 2020-11-16 设计创作，主要内容包括：本申请公开了一种变负载过程中的氮氧化物控制方法、装置及煤燃烧系统。该方法包括：获取负载指令,该负载指令中包括目标负载；根据所述目标负载计算校正后的风量输出值；根据预设的动态调整系数以及校正后的风量输出值,计算风量的目标输出值；基于所述目标输出值控制输送至所述燃煤锅炉中的风量。由于可以通过预设的动态调整系数来放大风量调整的幅度,因此在升负载和降负载的过程中,均能够降低风量调节速度与煤量调节速度之间的偏差,从而减少氮氧化物的产生。(The application discloses a method and a device for controlling nitrogen oxides in a variable load process and a coal combustion system. The method comprises the following steps: acquiring a load instruction, wherein the load instruction comprises a target load; calculating a corrected air volume output value according to the target load; calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value; and controlling the air quantity conveyed into the coal-fired boiler based on the target output value. Because the amplitude of air volume adjustment can be amplified through a preset dynamic adjustment coefficient, the deviation between the air volume adjustment speed and the coal volume adjustment speed can be reduced in the processes of load rising and load falling, and the generation of nitrogen oxides is reduced.)

1. A method for controlling nitrogen oxides in a variable load process of a coal-fired boiler is characterized by comprising the following steps:

acquiring a load instruction, wherein the load instruction comprises a target load;

calculating a corrected air volume output value according to the target load;

calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value;

and controlling the air quantity conveyed into the coal-fired boiler based on the target output value.

2. The nox control method according to claim 1, wherein before calculating the target output value of the air volume based on the preset dynamic adjustment coefficient and the corrected air volume output value, the method further comprises:

and calculating the preset dynamic adjustment coefficient according to the difference value between the target load and the actual load of the coal-fired boiler.

3. The method for controlling nitrogen oxides according to claim 2, wherein calculating the preset dynamic adjustment coefficient according to the difference between the target load and the actual load of the coal-fired boiler specifically comprises:

when the absolute value of the difference value between the target load and the actual load is less than or equal to a preset threshold value, the preset dynamic adjustment coefficient takes the value of 1;

when the coal-fired boiler is in a load increasing process and the absolute value of the difference value between the target load and the actual load is greater than the preset threshold, the value of the preset dynamic adjustment coefficient is a first dynamic adjustment coefficient greater than 1; or the like, or, alternatively,

when the coal-fired boiler is in a load reduction process and the absolute value of the difference value between the target load and the actual load is greater than the preset threshold, the value of the preset dynamic adjustment coefficient is a second dynamic adjustment coefficient smaller than 1.

4. The method of claim 3, wherein calculating the target output value of the air volume based on the preset dynamic adjustment factor and the corrected output value of the air volume comprises:

and taking the product of the preset dynamic adjustment coefficient and the air volume output value as the calculated target output value.

5. The method of claim 1, wherein obtaining a load command specifically comprises:

and acquiring the load instruction in real time.

6. The method of controlling nitrogen oxides according to claim 1, wherein calculating a corrected air volume output value based on the target load specifically comprises:

inputting the target load to a preset calculation formula of air volume, and calculating to obtain the corrected air volume output value; or the like, or, alternatively,

and calculating the corrected air volume output value according to the corresponding relation between the air volume and the load and the target load.

7. A nitrogen oxide control device in a variable load process of a coal-fired boiler is characterized by comprising: the device comprises an acquisition unit, an air volume correction output value calculation unit, an air volume target output value calculation unit and a control unit, wherein:

the obtaining unit is used for obtaining a load instruction, wherein the load instruction comprises a target load;

the air volume correction output value calculating unit is used for calculating a corrected air volume output value according to the target load;

the air volume target output value calculating unit is used for calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value;

and the control unit is used for controlling the air quantity conveyed into the coal-fired boiler based on the target output value.

8. The nox control apparatus according to claim 7, characterized by further comprising: and the dynamic adjustment coefficient calculating unit is used for calculating the preset dynamic adjustment coefficient according to the difference value between the target load and the actual load of the coal-fired boiler.

9. A coal combustion system, comprising: coal fired boiler, coal feeding device, air feed device, load equipment and nitrogen oxide controlling means, wherein:

the coal-fired boiler provides heat energy to the load equipment through coal combustion;

the coal feeding device is used for conveying coal to be combusted to the coal-fired boiler;

the nitrogen oxide control device includes: the device comprises an acquisition unit, an air volume correction output value calculation unit, an air volume target output value calculation unit and a control unit, wherein: the obtaining unit is configured to obtain a load instruction, where the load instruction includes a target load of the load device; the air volume correction output value calculating unit is used for calculating a corrected air volume output value according to the target load; the air volume target output value calculating unit is used for calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value; and the control unit is used for controlling the air quantity conveyed into the coal-fired boiler by the air supply device based on the target output value.

10. The coal combustion system as set forth in claim 9, further comprising: tail gas emission equipment and tail gas deNOx systems.

Technical Field

The application relates to the field of pollution gas emission control of coal-fired boilers, in particular to a method and a device for controlling nitrogen oxides in a variable load process and a coal combustion system.

Background

In industrial production, coal-fired power generation and other processes, heat energy can be provided by burning coal in a coal-fired boiler. When coal burning is performed in a coal-fired boiler, coal and air need to be introduced into the coal-fired boiler, and the amount of introduced coal and the amount of introduced air are generally determined according to the load of the coal-fired boiler, for example, when the load of the coal-fired boiler is a certain value, a certain amount of coal and the amount of air matched with the amount of coal are introduced into the coal-fired boiler.

However, in practical applications, the load of the coal-fired boiler often changes with time, and the adjustment speed of the coal quantity is usually faster than the adjustment speed of the air quantity, which may cause a deviation in matching between the introduced coal quantity and the air quantity, thereby generating excessive nitrogen oxides.

Disclosure of Invention

The embodiment of the application provides a method and a device for controlling nitrogen oxides in a variable load process and a coal combustion system, which are used for solving the problems in the prior art.

The embodiment of the application provides a method for controlling nitrogen oxides in a variable load process of a coal-fired boiler, which comprises the following steps:

acquiring a load instruction, wherein the load instruction comprises a target load;

calculating a corrected air volume output value according to the target load;

calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value;

and controlling the air quantity conveyed into the coal-fired boiler based on the target output value.

Preferably, before calculating the target output value of the air volume according to the preset dynamic adjustment coefficient and the corrected air volume output value, the method further includes:

and calculating the preset dynamic adjustment coefficient according to the difference value between the target load and the actual load of the coal-fired boiler.

Preferably, the calculating the preset dynamic adjustment coefficient according to the difference between the target load and the actual load of the coal-fired boiler specifically includes:

when the absolute value of the difference value between the target load and the actual load is less than or equal to a preset threshold value, the preset dynamic adjustment coefficient takes the value of 1;

when the coal-fired boiler is in a load increasing process and the absolute value of the difference value between the target load and the actual load is greater than the preset threshold, the value of the preset dynamic adjustment coefficient is a first dynamic adjustment coefficient greater than 1; or the like, or, alternatively,

when the coal-fired boiler is in a load reduction process and the absolute value of the difference value between the target load and the actual load is greater than the preset threshold, the value of the preset dynamic adjustment coefficient is a second dynamic adjustment coefficient smaller than 1.

Preferably, the calculating the target output value of the air volume according to the preset dynamic adjustment coefficient and the corrected air volume output value specifically includes:

and taking the product of the preset dynamic adjustment coefficient and the air volume output value as the calculated target output value.

Preferably, the obtaining of the load instruction specifically includes:

and acquiring the load instruction in real time.

Preferably, calculating a corrected air volume output value according to the target load specifically includes:

inputting the target load to a preset calculation formula of air volume, and calculating to obtain the corrected air volume output value; or the like, or, alternatively,

and calculating the corrected air volume output value according to the corresponding relation between the air volume and the load and the target load.

The embodiment of the application also provides a nitrogen oxide controlling means among coal fired boiler variable load process, includes: the device comprises an acquisition unit, an air volume correction output value calculation unit, an air volume target output value calculation unit and a control unit, wherein:

the obtaining unit is used for obtaining a load instruction, wherein the load instruction comprises a target load;

the air volume correction output value calculating unit is used for calculating a corrected air volume output value according to the target load;

the air volume target output value calculating unit is used for calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value;

and the control unit is used for controlling the air quantity conveyed into the coal-fired boiler based on the target output value.

Preferably, the nitrogen oxide control apparatus further includes: and the dynamic adjustment coefficient calculating unit is used for calculating the preset dynamic adjustment coefficient according to the difference value between the target load and the actual load of the coal-fired boiler.

The embodiment of the present application further provides a coal combustion system, including: coal fired boiler, coal feeding device, air feed device, load equipment and nitrogen oxide controlling means, wherein:

the coal-fired boiler provides heat energy to the load equipment through coal combustion;

the coal feeding device is used for conveying coal to be combusted to the coal-fired boiler;

the nitrogen oxide control device includes: the device comprises an acquisition unit, an air volume correction output value calculation unit, an air volume target output value calculation unit and a control unit, wherein: the obtaining unit is configured to obtain a load instruction, where the load instruction includes a target load of the load device; the air volume correction output value calculating unit is used for calculating a corrected air volume output value according to the target load; the air volume target output value calculating unit is used for calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value; and the control unit is used for controlling the air quantity conveyed into the coal-fired boiler by the air supply device based on the target output value.

Preferably, the coal combustion system further includes: tail gas emission equipment and tail gas deNOx systems.

The embodiment of the application adopts at least one technical scheme which can achieve the following beneficial effects:

by adopting the method for controlling the nitrogen oxides in the variable load process of the coal-fired boiler, after the load instruction is obtained, the corrected air volume output value is calculated according to the target load in the load instruction, then the target output value of the air volume is calculated according to the preset dynamic adjustment coefficient and the corrected air volume output value, and the air volume conveyed to the coal-fired boiler is controlled based on the target output value. After the target output value is obtained, the amount of air delivered to the coal-fired boiler may be controlled based on the target output value. Because the amplitude of air volume adjustment can be amplified through a preset dynamic adjustment coefficient, the deviation between the air volume adjustment speed and the coal volume adjustment speed can be reduced in the processes of load rising and load falling, and the generation of nitrogen oxides is reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic flow chart of a method for controlling nitrogen oxides in a variable load process of a coal-fired boiler according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a nitrogen oxide control device in a variable load process of a coal-fired boiler according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical solutions provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

As shown above, since the amount of coal introduced into the coal-fired boiler needs to be matched with the air volume, in practical applications, when the load of the coal-fired boiler changes with time, the adjustment speed of the amount of coal is usually faster than the adjustment speed of the air volume, which may cause a deviation in the matching between the amount of introduced coal and the air volume, thereby generating excessive nitrogen oxides.

Based on the above, the application provides a method for controlling nitrogen oxides in a variable load process of a coal-fired boiler, which can be used for solving the technical problems. The method for controlling nitrogen oxides in the variable load process of the coal-fired boiler shown in FIG. 1 can comprise the following steps:

step S11: and acquiring a load instruction, wherein the load instruction comprises a target load.

The target load may be a target load of a load device connected to the coal-fired boiler, for example, an actual load of the load device connected to the coal-fired boiler needs to be adjusted to the target load according to actual requirements.

For the timing of acquiring the load command, the load command may be acquired periodically (for example, every hour, half hour, or the like), or may be acquired in real time. Generally, for more precise control of the air volume, a method of acquiring a load instruction in real time may be adopted, for example, whether a user inputs a target load is monitored in real time, and when the user inputs the target load, the load instruction is generated.

Step S12: and calculating a corrected air volume output value according to the target load.

When the load instruction is obtained, it is described that the current actual load of the load equipment needs to be adjusted, and the air volume and the coal volume also need to be adjusted correspondingly, wherein the corrected air volume output value can be calculated according to the target load by adopting various ways.

In the first mode, the target load is input into a preset calculation formula of the air volume, and the corrected air volume output value is calculated, where the preset calculation formula may be obtained by summarizing and summarizing historical data, such as historical air volume and historical load, by using a function fitting method, and the like, so that after the target load is input into the preset calculation formula, the calculation result may be used as the corrected air volume output value.

In the second aspect, the corrected air volume output value may be calculated based on the correspondence between the air volume and the load and the target load. The corresponding relation between the air volume and the load can be directly set, and after the target load is obtained, the air volume corresponding to the target load is determined according to the corresponding relation.

Step S13: and calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value.

The preset dynamic adjustment coefficient can be used for adjusting the corrected air volume output value, so that a target output value of the air volume is obtained through calculation, and the amplitude of air volume adjustment can be amplified through the preset dynamic adjustment coefficient, so that for the adjustment result, for example, in the process of load increase (namely the load of load equipment is continuously increased, and the target load is usually greater than or equal to the actual load), the target output value of the air volume is greater than the corrected air volume output value, so that the air volume is further increased, and the deviation between the adjusting speed of the air volume and the adjusting speed of the coal volume is reduced; in the process of load reduction (that is, the load of the load equipment is continuously reduced, and at this time, the target load is usually smaller than or equal to the actual load), the target output value of the air volume is smaller than the corrected air volume output value, so that the air volume is further reduced, and the deviation between the air volume adjusting speed and the coal volume adjusting speed is also reduced.

Therefore, for the preset dynamic adjustment coefficient, it is usually determined according to the target load and the actual load of the coal-fired boiler, for example, a difference between the target load and the actual load may be calculated first, and then the preset dynamic adjustment coefficient may be calculated according to the magnitude of the difference, and the specific manner may be:

firstly, judging whether the absolute value of the difference is smaller than or equal to a preset threshold value, if so, indicating that the difference between the target load and the actual load is small, and normal parameter fluctuation possibly caused by equipment factors is caused, at the moment, setting the value of a preset dynamic adjustment coefficient as 1, and directly multiplying the preset dynamic adjustment coefficient by the corrected air volume output value when calculating the target output value of the air volume according to the preset dynamic adjustment coefficient and the corrected air volume output value, and taking the product as the target output value of the air volume. The preset threshold value is usually set according to specific situations, and may be, for example, 10 mw, 20 mw, or the like.

If the absolute value of the difference between the target load and the actual load is greater than the preset threshold, it may be further determined that the coal-fired boiler is specifically in the load-increasing process or the load-reducing process, for example, when the target load is greater than the actual load, the load-increasing process is described, or when the target load is less than the actual load, the load-reducing process is described.

At this time, if it is further determined that the load is increasing, the target output value needs to be adjusted to be greater than the corrected air volume output value, so that the preset dynamic adjustment coefficient may be taken as the first dynamic adjustment coefficient greater than 1, and when the target output value of the air volume is calculated based on the preset dynamic adjustment coefficient and the corrected air volume output value, the preset dynamic adjustment coefficient is directly multiplied by the corrected air volume output value, and the product is used as the target output value of the air volume. The first dynamic adjustment coefficient may be, for example, 1.01, 1.02, 1.05, 1.07, 1.1, or the like.

Or if the load reduction process is further determined, the target output value needs to be adjusted to be smaller than the corrected air volume output value, so that the preset dynamic adjustment coefficient can be taken as a second dynamic adjustment coefficient smaller than 1, and when the target output value of the air volume is calculated according to the preset dynamic adjustment coefficient and the corrected air volume output value, the preset dynamic adjustment coefficient is directly multiplied by the corrected air volume output value, and the product is taken as the target output value of the air volume. Wherein, the second dynamic adjustment coefficient can be 0.9, 0.93, 0.95, 0.98, 0.99, etc.

Step S14: the amount of air delivered to the coal fired boiler is controlled based on the target output value.

After the target output value is obtained, the amount of air delivered to the coal-fired boiler may be controlled based on the target output value. The preset dynamic adjustment coefficient is used for amplifying the air volume adjustment amplitude, for example, in the process of load increase, the target output value of the air volume is enabled to be larger than the corrected air volume output value, so that the air volume is further increased, in the process of load reduction, the target output value of the air volume is enabled to be smaller than the corrected air volume output value, so that the air volume is further decreased, in the processes of load increase and load reduction, the deviation between the air volume adjustment speed and the coal volume adjustment speed can be reduced, and the generation of nitrogen oxides is reduced.

The invention concept same as the nitrogen oxide control method in the variable load process of the coal-fired boiler provided by the embodiment of the application is adopted, and the embodiment of the application also provides a nitrogen oxide control device in the variable load process of the coal-fired boiler.

Fig. 2 is a schematic structural diagram of the nox control device 20, which includes: an acquisition unit 201, an air volume correction output value calculation unit 202, an air volume target output value calculation unit 203, and a control unit 204, wherein:

an obtaining unit 201, configured to obtain a load instruction, where the load instruction includes a target load;

an air volume correction output value calculation unit 202 for calculating a corrected air volume output value according to the target load;

the air volume target output value calculating unit 203 is used for calculating a target output value of the air volume according to a preset dynamic adjustment coefficient and the corrected air volume output value;

and a control unit 204 for controlling the amount of air delivered to the coal-fired boiler based on the target output value.

In practical applications, the nox control device 20 may further include: and the dynamic adjustment coefficient calculating unit 205 is configured to calculate a preset dynamic adjustment coefficient according to a difference between the target load and the actual load of the coal-fired boiler. When the dynamic adjustment coefficient calculation unit 205 calculates the preset dynamic adjustment coefficient according to the difference between the target load and the actual load of the coal-fired boiler, the calculation may be: when the absolute value of the difference value between the target load and the actual load is less than or equal to a preset threshold value, the value of a preset dynamic adjustment coefficient is 1; when the coal-fired boiler is in a load-increasing process and the absolute value of the difference value between the target load and the actual load is greater than a preset threshold value, the value of a preset dynamic adjustment coefficient is a first dynamic adjustment coefficient greater than 1; or when the coal-fired boiler is in the load reduction process and the absolute value of the difference value between the target load and the actual load is greater than the preset threshold value, the value of the preset dynamic adjustment coefficient is a second dynamic adjustment coefficient which is less than 1.

The air volume target output value calculating unit 203 may use a product between the preset dynamic adjustment coefficient and the air volume output value as the calculated target output value when calculating the target output value of the air volume according to the preset dynamic adjustment coefficient and the corrected air volume output value.

The acquiring unit 201 may acquire the load instruction in real time.

The air volume correction output value calculation unit 202 may calculate the corrected air volume output value according to the target load as follows: inputting the target load into a preset calculation formula of the air volume, and calculating to obtain a corrected air volume output value; or, calculating the corrected air volume output value according to the corresponding relation between the air volume and the load and the target load.

Of course, the embodiment of the present application may also provide a coal combustion system, which may include: coal fired boiler, coal feeding device, air feed device, load equipment and the nitrogen oxide control device that provides in the embodiment of this application, wherein:

the coal feeding device can be used for conveying coal to be combusted into the coal-fired boiler; the air supply device can be used for conveying air for combustion supporting in the coal-fired boiler; the load device may be a generator set or other industrial rotating load device, and the coal-fired boiler provides heat energy to the load device by burning coal.

At this time, the load instruction obtained by the obtaining unit of the nitrogen oxide control device includes the target load of the load device; an air volume correction output value calculation unit of the nitrogen oxide control device, which can calculate the corrected air volume output value according to the target load; the air volume target output value calculating unit of the nitrogen oxide control device can calculate the target output value of the air volume according to the preset dynamic adjustment coefficient and the corrected air volume output value; and the control unit of the nitrogen oxide control device can control the air quantity delivered to the coal-fired boiler by the air supply device based on the target output value.

In practical application, in order to discharge the flue gas generated in the coal-fired boiler, the coal combustion system may further include a tail gas discharge device and a tail gas denitration system, and the tail gas denitration system may be a Selective Catalytic Reduction (SCR) system, so that the tail gas is discharged from the tail gas discharge device after being denitrated by the SCR system.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.