阅读说明：本技术 一种循环流化床锅炉风量控制方法、系统及装置 (Method, system and device for controlling air quantity of circulating fluidized bed boiler ) 是由 史春方 赵立军 张春山 隋成平 于 2020-06-23 设计创作，主要内容包括：本发明公开了一种循环流化床锅炉风量控制方法、系统及装置,包括当当前锅炉负荷大于或等于第一负荷时,根据公式F<Sub>Z</Sub>＝MAX{Z,[F(X<Sub>i</Sub>)+W]}+K×FTm+F<Sub>Y</Sub>,计算总风量F<Sub>Z</Sub>,并根据所述总风量F<Sub>Z</Sub>控制锅炉风机动作。应用本发明提供的循环流化床锅炉风量控制方法及系统,通过锅炉负荷与一次风量间的模糊函数得到一次风量,当高低负荷切换时,将锅炉负荷变化所对应的一次风量变化量和总煤量的比值、即一次风变化风量的风煤比作为二次风风煤比的初始值对二次风量进行控制,并根据预设个数的周期中的二次风煤比K计算下一周期的K,由此以实时调节负荷变化引起燃料变化时所需求的风量,使得在高低负荷切换时根据锅炉负荷调整风量,实现自适应。(The invention discloses a method, a system and a device for controlling the air quantity of a circulating fluidized bed boiler, which comprises the following steps that when the current boiler load is more than or equal to a first load, the air quantity is controlled according to a formula F Z ＝MAX{Z,[F(X i )+W]}+K×FTm+F Y Calculating the total air volume F Z According to the total air quantity F Z And controlling the action of the boiler fan. By applying the method and the system for controlling the air volume of the circulating fluidized bed boiler, the primary air volume is obtained through a fuzzy function between the boiler load and the primary air volume, when high and low loads are switched, the secondary air volume is controlled by taking the ratio of the primary air volume variation corresponding to the boiler load variation and the total coal volume, namely the air-coal ratio of the primary air volume variation as the initial value of the secondary air-coal ratio, and the next period K is calculated according to the secondary air-coal ratio K in the preset number of periods, so that the air volume required when the fuel is changed due to load variation is adjusted in real time, the air volume is adjusted according to the boiler load during high and low load switching, and self-adaptation is realized.)

1. A method for controlling air quantity of a circulating fluidized bed boiler is characterized by comprising the following steps:

when the current boiler load is greater than or equal to the first load, according to the formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_Z；

According to the total air volume F_ZControlling the action of a boiler fan;

wherein Z is the initial value of the minimum fluidization primary air quantity;

F(X_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load;

w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load;

F_Ythe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value;

FTm is total coal amount;

k is a secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the preset number, and the initial value of K is

2. The circulating fluidized bed boiler air volume control method of claim 1, further comprising:

when the current boiler load is less than the first load, according to formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_Z', and according to said total primary air quantity F_Z' controlling the action of a boiler fan.

3. The circulating fluidized bed boiler air volume control method of claim 1, further comprising:

judging whether the periodicity of the current period is greater than or equal to a preset periodicity M;

if yes, the secondary air-coal ratio K of the next period is equal to the weighted average value of the secondary air-coal ratios K of the previous M periods;

if not, the secondary air-coal ratio K of the next period is the passing formulaIs calculated to obtain, wherein, F_ZIs the total air volume of the previous period, Z is the initial value of the minimum fluidization primary air volume of the previous period, F (X)_i) Primary air volume for the previous cycle, W is the primary air volume correction for the previous cycle, and FTm is the total coal volume for the previous cycle.

4. A circulating fluidized bed boiler air volume control system, characterized by comprising:

the boiler load judging module is used for judging whether the current boiler load is larger than or equal to a first load or not, and if so, triggering the total air volume calculating module to start;

the total air volume calculating module is used for calculating the total air volume according to a formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_ZWherein Z is the initial value of the minimum fluidization primary air quantity; f (X)_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load; w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load; f_YThe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value; FTm is total coal amount; k is a secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the preset number, and the initial value of K isTriggering the air volume control module to start;

the air volume control module is used for controlling the air volume according to the total air volume F_ZAnd controlling the action of the boiler fan.

5. The circulating fluidized bed boiler air volume control system of claim 4, wherein the boiler load determination module is further configured to:

when the current boiler load is smaller than the first load, triggering a primary air total amount calculation module to start;

the primary air total amount calculating module is used for calculating the total primary air amount according to a formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_Z' and triggering the air volume control module to start;

the air volume control module is used for controlling the air volume according to the total primary air volume F_Z' controlling the action of a boiler fan.

6. The circulating fluidized bed boiler air volume control system of claim 4, wherein the total air volume calculation module further comprises:

the secondary air-coal ratio calculating unit is used for judging whether the periodicity of the current period is greater than or equal to a preset periodicity M; if yes, the secondary air-coal ratio K of the next period is equal to the weighted average value of the secondary air-coal ratios K of the previous M periods; if not, the secondary air-coal ratio K of the next period is the passing formulaIs calculated to obtain, wherein, F_ZIs the total air volume of the previous period, Z is the initial value of the minimum fluidization primary air volume of the previous period, F (X)_i) Primary air volume for the previous cycle, W is the primary air volume correction for the previous cycle, and FTm is the total coal volume for the previous cycle.

7. A circulating fluidized bed boiler air volume control device is characterized by comprising:

a memory for storing a computer program;

a processor for implementing the steps of the circulating fluidized bed boiler air volume control method according to any one of claims 1 to 3 when executing the computer program.

Technical Field

The invention relates to the technical field of boiler air supply control, in particular to an air volume control method of a circulating fluidized bed boiler, and further relates to an air volume control system and device of the circulating fluidized bed boiler.

Background

In the combustion process of the circulating fluidized bed boiler, fuel is required to be matched with an air supply system to complete the whole combustion process, but in the circulating fluidized bed, the air supply system is divided into primary air and secondary air, when the load is high and low, the air quantity is different when the load is high and low due to different design modes of different boiler manufacturers, the primary air design of some manufacturers can reach 50% -60% of load, and the secondary air is required to participate in when the load is more than 60% to complete the whole combustion process, but the proportion is different, so that the automatic adaptation of the primary air and the secondary air in the whole load interval is the basic requirement for the automatic combustion of the whole load interval.

In the existing control system, the air quantity requirement is determined by combining the combustion in a furnace and the fuel quantity requirement target, the air quantity ratio can be simply realized in the high load and low load interval except the high and low critical loads, but when the high and low critical loads are switched, the operating frequency of a primary fan and a secondary fan needs to be manually changed to change the air-coal ratio to ensure the oxygen quantity requirement, the combustion stability is ensured, the adjusting process time is long, and different operating personnel experience is different, so that the adjusting process time is different. During the combustion process, the coal quality changes, the air quantity also needs to be automatically adapted, and how to realize the automatic adaptation switching of the air quantity in a full-load interval is difficult to realize by common automatic control.

Disclosure of Invention

In view of the above, a first objective of the present invention is to provide a method for controlling an air volume of a circulating fluidized bed boiler, so as to solve the problem that the conventional air volume is not adaptive to the air volume of the circulating fluidized bed boiler when the air volume is changed in accordance with the switching between the high air volume and the low air volume. The invention provides a system and a device for controlling the air quantity of the circulating fluidized bed boiler. In order to achieve the first object, the invention provides the following technical scheme:

a method for controlling air quantity of a circulating fluidized bed boiler comprises the following steps:

when the current boiler load is greater than or equal to the first load, according to the formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total windQuantity F_Z；

According to the total air volume F_ZControlling the action of a boiler fan;

wherein Z is the initial value of the minimum fluidization primary air quantity;

F(X_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load;

w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load;

F_Ythe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value;

FTm is total coal amount;

k is a secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the preset number, and the initial value of K is

Preferably, the method further comprises:

when the current boiler load is less than the first load, according to formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_Z', and according to said total primary air quantity F_Z' controlling the action of a boiler fan.

Preferably, the method further comprises:

judging whether the periodicity of the current period is greater than or equal to a preset periodicity M;

if yes, the secondary air-coal ratio K of the next period is equal to the weighted average value of the secondary air-coal ratios K of the previous M periods;

if not, the secondary air-coal ratio K of the next period is the passing formulaIs calculated to obtain, wherein, F_ZIs the total air volume of the previous period, Z is the initial value of the minimum fluidization primary air volume of the previous period, F (X)_i) Primary air volume for the previous cycle, W is the primary air volume correction for the previous cycle, and FTm is the total coal volume for the previous cycle.

The invention also provides a circulating fluidized bed boiler air volume control system, which comprises:

the boiler load judging module is used for judging whether the current boiler load is larger than or equal to a first load or not, and if so, triggering the total air volume calculating module to start;

the total air volume calculating module is used for calculating the total air volume according to a formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_ZWherein Z is the initial value of the minimum fluidization primary air quantity; f (X)_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load; w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load; f_YThe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value; FTm is total coal amount; k is a secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the preset number, and the initial value of K isTriggering the air volume control module to start;

the air volume control module is used for controlling the air volume according to the total air volume F_ZAnd controlling the action of the boiler fan.

Preferably, the boiler load judgment module is further configured to:

when the current boiler load is smaller than the first load, triggering a primary air total amount calculation module to start;

the primary air total amount calculating module is used for calculating the total primary air amount according to a formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_Z' and triggering the air volume control module to start;

the air volume control module is used for controlling the air volume according to the total primary air volume F_Z' controlling the action of a boiler fan.

Preferably, the total air volume calculating module further includes:

the secondary air-coal ratio calculating unit is used for judging whether the periodicity of the current period is greater than or equal to a preset periodicity M; if yes, the next cycleThe secondary air-coal ratio K is equal to the weighted average of the secondary air-coal ratios K of the previous M periods; if not, the secondary air-coal ratio K of the next period is the passing formulaIs calculated to obtain, wherein, F_ZIs the total air volume of the previous period, Z is the initial value of the minimum fluidization primary air volume of the previous period, F (X)_i) Primary air volume for the previous cycle, W is the primary air volume correction for the previous cycle, and FTm is the total coal volume for the previous cycle.

A circulating fluidized bed boiler air volume control device comprises:

a memory for storing a computer program;

a processor for implementing the steps of the circulating fluidized bed boiler air volume control method according to any one of the above when executing the computer program.

The invention provides a method for controlling the air quantity of a circulating fluidized bed boiler, which comprises the following steps: when the current boiler load is greater than or equal to the first load, according to the formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_ZAccording to the total air quantity F_ZAnd controlling the action of the boiler fan.

By applying the method and the system for controlling the air volume of the circulating fluidized bed boiler, the primary air volume is obtained through a fuzzy function between the boiler load and the primary air volume, when high and low loads are switched, the ratio of the primary air volume variation corresponding to the boiler load variation to the total coal volume, namely the air-coal ratio of the primary air variation is used as the initial value of the secondary air-coal ratio to control the secondary air volume, and the K of the next period is calculated according to the secondary air-coal ratio K in the preset number of periods, so that the air volume required when fuel is changed due to load variation is adjusted in real time, the air volume is adjusted according to the boiler load during high and low load switching, and self-adaption is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for controlling air volume of a circulating fluidized bed boiler according to an embodiment of the present invention.

Detailed Description

The embodiment of the invention discloses an air quantity control method of a circulating fluidized bed boiler, which aims to solve the problem that the existing air quantity can not realize self-adaption by manually replacing primary air quantity and secondary air quantity when the air quantity is in accordance with switching.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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 invention.

Referring to fig. 1, fig. 1 is a schematic flow chart of a method for controlling air volume of a circulating fluidized bed boiler according to an embodiment of the present invention.

In a specific embodiment, the invention provides a method for controlling air volume of a circulating fluidized bed boiler, which comprises the following steps:

s11: when the current boiler load is greater than or equal to the first load, according to the formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_Z；

S12: according to the total air volume F_ZControlling the action of a boiler fan;

the first load may be set according to the load capacity of the boiler, and is generally considered to be a low load range at 40% to 55% or less and a high load range at 40% to 55% or more. Z is the initial value of the minimum fluidization primary air quantity; the initial value of the minimum fluidization primary air quantity is set according to the particle size of the bed material.

F(X_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load; primary air quantity fuzzy function F (X)_i) In normal operation, the inflection point of each input variable in the function is increased by an increment value corresponding to the last cycle of the output variable, and in one embodiment, the fuzzy function between the boiler load and the primary air volume is shown in table 1 below. Wherein, X_iIs the current boiler load (t/h), F (X)_i) The primary air volume (Km 3/h).

xi	0	95	110	125	140	155	170	185	200	215	230
												F(Xi)	62	66	70	74	78	82	86	90	92	92	92

TABLE 1

In other embodiments, F (X) may be set as desired_i) Such as linear functions, polygonal line functions or other types of functional relationships, are within the scope of the present invention.

W is a primary air volume correction value obtained by a field combustion parameter corresponding to the current boiler load; the field combustion parameters comprise material bed differential pressure, bed temperature, coal feeding quantity and the like, the change of any parameter changes the requirement of primary air quantity, a preset function model is obtained according to the field combustion parameters and the requirement change coefficient of the primary air quantity, and a primary air quantity correction value is obtained according to the field combustion parameters.

Likewise, F_YThe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value; the relation function between the oxygen deviation value and the secondary air volume correction value is according to a preset function.

FTm is total coal amount;

k is the secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the previous preset number, and the initial value of K is

In the first period after the current boiler load is greater than or equal to the first load, the initial value of K isWherein, Δ F (X)_i) The amount of change in the primary air, i.e., the amount of change in the primary air after load switching, is F (X) corrected based on the load change at the time of switching and the secondary air volume change after the secondary air is turned on after load switching_i) And comparing the change amount of the primary air quantity in the previous period (the boiler load in the period is smaller than the first load) to obtain the change amount of the primary air, and taking the air-coal ratio of the change of the primary air quantity as the initial air-coal ratio of the secondary air.

And calculating to obtain the total air volume F_ZIn the second period, K is the total air volume F in the first period_Z、Z、F(X_i) W and FTm are calculated to obtain,and K is K1, and the air volume of the next period is continuously adjusted according to the formula by the secondary air coal ratio of the previous period.

By applying the method and the system for controlling the air volume of the circulating fluidized bed boiler, the primary air volume is obtained through a fuzzy function between the boiler load and the primary air volume, when high and low loads are switched, the secondary air volume is controlled by taking the ratio of the primary air volume variation corresponding to the boiler load variation and the total coal volume, namely the air-coal ratio of the primary air volume variation as the initial value of the secondary air-coal ratio, and the next period K is calculated according to the secondary air-coal ratio K in the preset number of periods, so that the air volume required when the fuel is changed due to load variation is adjusted in real time, the air volume is adjusted according to the boiler load during high and low load switching, and self-adaptation is realized.

Further, the method further comprises:

judging whether the periodicity of the current period is greater than or equal to a preset periodicity M;

if yes, the secondary air-coal ratio K of the next period is equal to the weighted average value of the secondary air-coal ratios K of the previous M periods;

if not, the secondary air-coal ratio K of the next period is the total air volume passing through the previous periodAnd (4) calculating.

As indicated above, M may be set to 4, and in the fifth period, the overfire air-coal ratio K is equal to the weighted average of the overfire air-coal ratios of the aforementioned M periods, which are understood to be the number of periods counted after the boiler load is equal to or greater than the first load. In one embodiment, the average value can be calculated directly, and the frequency is set according to the requirement. When the periodicity of the current period is less than the preset period, the total air volume F of the previous period is passed_Z、Z、F(X_i) W and FTm calculate the secondary air-coal ratio K of the next period to realize the self-adaptive adjustment of the whole load interval.

Specifically, the method further comprises:

when the current boiler load is less than the first load, according to the formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_ZAccording to the total amount of primary air F_Z' controlling the action of a boiler fan. Wherein, as described above, Z is the initial value of the minimum fluidization primary air volume; f (X)_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler load; w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load; therefore, the self-adaptive change of the air volume in the full-load interval is realized, the combustion change can be automatically adapted to the combustion change in the high-low load interval, the primary and secondary air volume change can be automatically corrected, the combustion stability and efficiency are ensured, and the combustion stable state is improved.

Based on the above method embodiment, the present invention further provides a circulating fluidized bed boiler air volume control system, which includes:

the boiler load judging module is used for judging whether the current boiler load is larger than or equal to a first load or not, and if so, triggering the total air volume calculating module to start;

the total air volume calculating module is used for calculating the total air volume according to a formula F_Z＝MAX{Z,[F(X_i)+W]}+K×FTm+F_YCalculating the total air volume F_ZWherein Z is the initial value of the minimum fluidization primary air quantity; f (X)_i) As a fuzzy function between boiler load and primary air quantity, X_iIs the current boiler loadLoading; w is a primary air volume correction value obtained by the field combustion parameter corresponding to the current boiler load; f_YThe secondary air volume correction value corresponding to the deviation of the real-time oxygen volume value and the target oxygen volume value; FTm is total coal amount; k is a secondary air-coal ratio and is obtained by calculation according to the secondary air-coal ratio K in the period of the preset number, and the initial value of K isTriggering the air volume control module to start;

the air volume control module is used for controlling the air volume according to the total air volume F_ZAnd controlling the action of the boiler fan.

By applying the method and the system for controlling the air volume of the circulating fluidized bed boiler, the primary air volume is obtained through a fuzzy function between the boiler load and the primary air volume, when high and low loads are switched, the secondary air volume is controlled by taking the ratio of the primary air volume variation corresponding to the boiler load variation and the total coal volume, namely the primary air-coal ratio, as the initial value of the secondary air-coal ratio, and the K of the next period is calculated according to the secondary air-coal ratio K in the preset number of periods, so that the air volume required when fuel is changed due to load variation is adjusted in real time, the air volume is adjusted according to the boiler load when high and low loads are switched, and self-adaption is realized.

In one embodiment, the boiler load determination module is further configured to:

when the current boiler load is smaller than the first load, triggering a primary air total amount calculation module to start;

a primary air total amount calculating module for calculating the total amount of primary air according to the formula F_Z'＝MAX{Z,[F(X_i)+W]Calculating the total amount of primary air F_Z' and triggering the air volume control module to start;

an air volume control module for controlling the air volume according to the total amount of primary air F_Z' controlling the action of a boiler fan.

Specifically, the total air volume calculating module further includes:

the secondary air-coal ratio calculating unit is used for judging whether the periodicity of the current period is greater than or equal to a preset periodicity M; if yes, the secondary air-coal ratio K of the next period is equal to the previous M periodsThe weighted average of the secondary air-coal ratio K; if not, the secondary air-coal ratio K of the next period is the passing formulaIs calculated to obtain, wherein, F_ZIs the total air volume of the previous period, Z is the initial value of the minimum fluidization primary air volume of the previous period, F (X)_i) Primary air volume for the previous cycle, W is the primary air volume correction for the previous cycle, and FTm is the total coal volume for the previous cycle.

The invention also provides a circulating fluidized bed boiler air volume control device, which comprises:

a memory for storing a computer program;

a processor for implementing the steps of the circulating fluidized bed boiler air volume control method according to any one of the above when executing the computer program.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.