A combustion optimization control method based on boiler CT technology

Abstract

The present invention relates to a combustion optimization control method based on boiler CT technology, comprising the steps of burner grouping, temperature acquisition, temperature comparison and burner adjustment. The combustion optimization control method based on boiler CT technology provided by the present invention solves the technical problem that the boiler combustion deviation and the resulting temperature deviation are difficult to control in real time and automatically during the boiler combustion adjustment process.

Description

Technical Field

[0001] The invention relates to a combustion optimization control method based on boiler CT technology, belonging to the technical field of boilers. Background Art

[0002] At present, most of the boiler combustion control of thermal power units in my country has achieved automatic operation, and the combustion load can be changed automatically according to the load change of the unit during boiler operation. In the "boiler and machine" automatic coordination mode, the steam turbine controls the power generation load, and the boiler combustion system controls the main steam pressure. When the main steam pressure set value deviates from the actual value, the DCS system boiler combustion automatic control loop issues an adjustment command to adjust the boiler fuel and the corresponding air distribution in time to maintain the stability of the boiler load.

[0003] For most thermal power plant boilers, for example, a fully gas-fired boiler, there are multiple burners. The combustion regulation and air distribution regulation of multiple burners are independent of each other. Burners at the same vertical height are burners on the same layer; burners on the same wall and at the same vertical height are burners in the same group.

[0004] The boiler combustion system is equipped with a gas regulating valve and a gas branch regulating valve. The valve group on the same level receives the regulating command from the boiler combustion automatic control loop regulator, and transmits the regulating command to each branch regulating valve through the regulating valve level operator to keep the branch regulating valve at the same opening.

[0005] The boiler combustion system is also equipped with an air volume regulating valve and an air volume branch regulating valve. The boiler has a double-row air blower arrangement. Generally, the boiler air supply is achieved by changing the output of the two air blowers according to the flue gas oxygen content in the horizontal flue and the appropriate air-coal ratio, so that the boiler burns economically. After being heated by the air preheater, the double-sided air supply is sent to the burner by the air volume regulating valve and the air volume branch regulating valve. The valve group command distribution principle is consistent with the gas regulating valve group.

[0006] The automatic boiler combustion and air volume have reduced the operating burden of operators. However, as the boiler runs longer, the fuel quantity, air volume and burner structure deviations between the burners will continue to deteriorate. Minor deviations will continue to accumulate and increase as the boiler runs longer, eventually leading to increasing temperature deviations in the burner area when the boiler is running, which in turn leads to: large deviations in boiler flue gas, increased deviations in the boiler heating surface, increasing deviations in the radiation convection heating surface, increased deviations in the opening of the water spray desuperheaters on both sides of the boiler, and increased loss of heating surface life, which can seriously affect the safe operation of the boiler.

[0007] Therefore, for boilers with combustion systems, it is necessary to take targeted measures to reduce the thermal deviation of the boiler heating surface according to the thermal deviation of the boiler, and try to control the thermal deviation within a controllable range, so as to extend the safe operation time and service life of the boiler. Traditionally, operators often make manual combustion adjustments based on the flue gas temperature deviation in the middle and rear ends of the boiler flue gas process, and the adjustment effect is not good. Especially in the process of large-scale and repeated changes in boiler load, the lag of the above adjustment method is more obvious, and it is difficult to achieve the purpose of timely reducing the thermal deviation of the boiler. In theory, the thermal deviation adjustment based on the temperature of the burner area is more timely and more conducive to timely control of thermal deviation from the front end of the flue gas process. Summary of the invention

[0008] The technical problem to be solved by the present invention is: to overcome the shortcomings of the above-mentioned technology, to provide a method for optimizing boiler combustion by using the temperature field distribution data obtained by boiler CT, to design a burner leveling optimization control strategy, an optimal total air volume control strategy and an air door leveling optimization control strategy, to realize automatic leveling of the temperature field in the boiler burner area, and then to realize automatic leveling of boiler combustion, to reduce the thermal deviation of flue gas along the process, to reduce the thermal deviation of the boiler heating surface, and to realize a method for optimizing boiler combustion.

[0009] In order to solve the above technical problems, the technical solution proposed by the present invention is: a combustion optimization control method based on boiler CT technology, comprising the following steps:

[0010] Step 1: The first grouping method: group the burners located on the same furnace wall of the boiler and with the same height into one group; The second grouping method: divide the burners into a left burner group and a right burner group with the center line of the front-to-back direction of the boiler as the axis;

[0011] Step 2: finding the intersection of each group after the first grouping method in step 1 and each group after the second grouping method; collecting the temperature field information and oxygen field information of the burner area in the obtained intersection through the boiler CT system;

[0012] Step 3: gas leveling of burners in the same group; take a group of burner groups after the first grouping method; read its temperature field information; compare the left temperature characterization value TiLavg with the right temperature characterization value TiRavg, if the two are consistent, do not adjust, if TiLavg is greater than TiRavg, then reduce the gas valve of the burner in the group that intersects with the left burner group, and at the same time increase the gas valve of the burner in the group that intersects with the right burner group; if TiLavg is less than TiRavg, then increase the gas valve of the burner in the group that intersects with the left burner group, and at the same time reduce the gas valve of the burner in the group that intersects with the right burner group; repeat this step until all burner groups in the first grouping method are adjusted;

[0013] Step 4: gas leveling of burners on the same layer; take all highly consistent groups in the first grouping method; read the temperature field information of each group; average the temperature characterization value on the left side and the temperature characterization value on the right side of each group; if the average values ​​of each group are consistent, no adjustment is made; if they are inconsistent, increase the gas valve of the burner group with a smaller average value, and decrease the gas valve of the burner group with a larger average value; repeat this step until all groups in the first grouping method are adjusted;

[0014] Step 5: Leveling the air volume of the burners in the same group; take a group of burner groups after the first grouping method; read its oxygen field information; compare the left oxygen value OiLavg with the right oxygen value OiRavg, if the two are consistent, do not adjust, if OiLavg is greater than OiRavg, then reduce the air volume valve of the burner in the group that intersects with the left burner group, and at the same time increase the air volume valve of the burner in the group that intersects with the right burner group; if OiLavg is less than OiRavg, then increase the air volume valve of the burner in the group that intersects with the left burner group, and at the same time reduce the air volume valve of the burner in the group that intersects with the right burner group; repeat this step until all burner groups in the first grouping method are adjusted;

[0015] Step 6: Level the air volume of the burners on the same floor; take all highly consistent groups in the first grouping method; read the oxygen field information of each group; average the oxygen value characterization value on the left and the oxygen value characterization value on the right of each group. If the average values ​​of each group are consistent, no adjustment is made. If not, increase the air volume valve of the burner group with a small average value, and decrease the gas valve of the burner group with a large average value; repeat this step until all groups in the first grouping method are adjusted.

[0016] A further improvement of the above scheme is that in step 3, the adjustment amount of the gas valve that is adjusted up and the gas valve that is adjusted down at the same time are the same, and the adjustment directions are opposite.

[0017] The above scheme is further improved in that: in step 3, a PID regulator is used to adjust the gas valve; the difference between TiLavg and TiRavg is divided into four sections, the first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius; the proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c], when the difference between TiLavg and TiRavg is in the first section, [a, b, c] = [1, 0.8, 0]; in the second section, [a, b, c] = [1, 1, 0]; in the third section, [a, b, c] = [1.3, 1.1, 0]; in the fourth section, [a, b, c] = [1.4, 1.1, 0].

[0018] A further improvement of the above scheme is that in step 4, the adjustment amount of the gas valve that is adjusted up and the gas valve that is adjusted down at the same time are the same, and the adjustment directions are opposite.

[0019] The above scheme is further improved in that: in step 4, a PID regulator is used to adjust the gas valve; the difference in average values ​​is divided into four sections, the first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius; the proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c], when the difference in average values ​​is in the first section, [a, b, c] = [1, 0.9, 0]; when it is in the second section, [a, b, c] = [1.1, 1, 0]; when it is in the third section, [a, b, c] = [1.3, 1.2, 0]; when it is in the fourth section, [a, b, c] = [1.4, 1.2, 0].

[0020] The above scheme is further improved in that: according to the analysis of boiler performance data and boiler combustion adjustment test, the optimal temperature field data corresponding to the boiler in different load sections is obtained. When the boiler can burn in the optimal temperature field condition, its air distribution is also in the best matching state. Measure and record the total air volume of the blowers on both sides of the boiler. In the actual operation of the boiler, the optimal total air volume model is used instead of the oxygen correction model; the optimal total air volume model inputs the boiler load, and automatically outputs the corresponding optimal total air volume in the form of a linear broken line function. The optimal total air volume is used as the target value for controlling the output of the blower, thereby obtaining a more accurate air distribution instruction than oxygen correction, and then giving the basic opening instruction for the air volume adjustment of each layer of the burner; at the same time, the air supply PID regulator introduces the main steam pressure as a feedforward signal to ensure that the air supply volume is adjusted in time when the boiler operating conditions change, and maintain the stability of the ratio of air supply volume to gas volume.

[0021] The above scheme is further improved in that: the air supply PID feedforward setting is specifically to obtain the main steam pressure in real time, and use a numerical analysis algorithm to calculate the main steam pressure change rate per minute; determine whether it exceeds the preset value a0, or is lower than the preset value a1; if it exceeds the preset value a0, the feedforward gain coefficient K=Kmax, if it is lower than the preset value a1, the feedforward gain coefficient K=Kmin, otherwise the feedforward gain coefficient K=Knor; the main steam pressure is multiplied by the feedforward gain coefficient K, which is used as the PID feedforward signal, and acts together on the control output of the air supply fan inverter.

[0022] The above scheme is further improved in that: a0=0.6, a1=0.2, the feedforward gain coefficient K varies in the range of [0.1, 0.2]; when the main steam pressure change rate per minute is greater than 0.6Mpa, K=Kmax=0.2, when the main steam pressure change rate per minute is less than 0.2Mpa, K=Kmin=0.1, otherwise K=Knor=0.15.

[0023] The combustion optimization control method based on boiler CT technology provided by the present invention solves the technical problem that the boiler combustion deviation and the resulting temperature deviation are difficult to control in real time and automatically during the boiler combustion adjustment process, and directly controls the thermal deviation from the front end of the flue gas process in a timely manner, and responds in a timely manner. Traditional boiler combustion automatic control can only issue burner operation instructions based on unit demand, but cannot independently perform fuel and air supply precision matching for each branch burner. Different from traditional control methods, the present invention proposes for the first time to use the boiler burner area temperature field signal and oxygen content signal measured by the boiler CT as signals for controlling boiler combustion deviations. When there is a small deviation in boiler combustion, the corresponding valve group is controlled and leveled, which can not only slow down or eliminate the continued expansion of the boiler combustion deviation, but also ensure that there will be no large deviation in oxygen content, thereby ensuring that the boiler fuel can be burned economically. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an application scenario of a preferred embodiment of the present invention.

[0025] Figure 2 yes Figure 1 Schematic diagram of the lower burner structure.

[0026] Figure 3 yes Figure 1 Schematic diagram of boiler automatic control method. DETAILED DESCRIPTION Example

[0027] In the combustion optimization control method based on boiler CT technology of this embodiment, N×N measurement grids and N pairs of measurement probes are configured on the furnace cross-sectional channel. The probes are installed on the boiler water-cooled wall. Holes are opened in the water-cooled wall fins as laser measurement channels to obtain the average temperature of N measurement paths. The CT imaging technology inversion algorithm is used to calculate the values ​​of the corresponding channel intersections. The furnace distribution of the temperature field is reproduced through the algorithm, and finally the furnace temperature field data and images are obtained.

[0028] The following takes Meishan Steel's 4# boiler as an example for explanation. Figure 1 and Figure 2As shown in the figure, the boiler has 6 burners on the front and rear walls, each of which is equipped with a corresponding gas branch pipe regulating valve and air volume branch pipe regulating valve, so as to achieve independent regulation of each burner; at the same time, the three burners located at the same height of the same furnace wall are also synchronously controlled by the gas regulating valve and the air volume regulating valve. The boiler is controlled by the DCS system, and the gas branch pipe regulating valve, air volume branch pipe regulating valve, gas regulating valve and air volume regulating valve are controlled by the PID regulator.

[0029] The specific steps include:

[0030] Step 1: The first grouping method: the burners located on the same furnace wall of the boiler and with the same height are grouped together, that is, the burners in this embodiment are divided into four groups: front upper, front lower, rear upper, and rear lower, each group having 3 burners; The second grouping method: the burners are divided into a left burner group and a right burner group with the center line of the front-to-back direction of the boiler as the axis. Since the middle burner is just located on the center line, it is excluded.

[0031] Step 2: Intersect each group after the first grouping method in step 1 with each group after the second grouping method; in this way, the first front upper burner, the third front upper burner, the first rear upper burner, the third rear upper burner, the front lower burner 1f, the front lower burner 3f, the rear lower burner 1b, and the rear lower burner 3b are obtained; the temperature field information and oxygen field information of the area where these burners are located in the intersection are collected through the boiler CT system; the communication is communicated to the DCS system through the 485 communication method; the communication monitoring function is designed, and the communication monitoring function has the following characteristics: when the communication is abnormal, the temperature field signal and oxygen field signal transmitted from the boiler CT system to the DCS system can automatically maintain the value before the communication abnormality, and issue a communication abnormality alarm prompt.

[0032] Step 3: Leveling of the gas of the burners in the same group; Take a group of burners after the first grouping method; Read its temperature field information; After eliminating the data that obviously deviates from the design process, use the cluster analysis method to analyze the temperature on the same side of the remaining data, and obtain the temperature signal that best represents the combustion situation of the combustion area on this side; Perform Kalman filtering on the data to eliminate signal jumps, avoid the influence of signal jumps on the optimization of leveling combustion, and grasp the changes in the temperature field in this area to predict the changes in the temperature field; Compare the temperature representation value TiLavg on the left with the temperature representation value TiLavg on the right The value TiRavg is compared, if the two are consistent, no adjustment is made; if TiLavg is greater than TiRavg, then the gas valve of the burner in the group that intersects with the left burner group is reduced, and the gas valve of the burner in the group that intersects with the right burner group is increased; if TiLavg is less than TiRavg, then the gas valve of the burner in the group that intersects with the left burner group is increased, and the gas valve of the burner in the group that intersects with the right burner group is reduced; repeat this step until all burner groups in the first grouping method are adjusted.

[0033] Taking the upper burner group as an example, T1Lavg of the first upper front burner is compared with T1Ravg of the third upper front burner; if the two are inconsistent, the PID regulator outputs the adjustment instruction OP1z, which only indicates the adjustment amount and has no direction; if T1Lavg>T1Ravg; then the adjustment optimization instruction OP1zL=OP1z*(-1) for the first upper front gas branch control valve is expressed by a negative value for the adjustment direction, that is, to reduce, and at the same time, the adjustment optimization instruction OP1zR=OP1z*1 for the third upper front gas branch control valve is expressed by a positive value for the adjustment direction, that is, to reduce; if T1Lavg<T1Ravg; then the adjustment optimization instruction OP1zL=OP1z*1 for the first upper front gas branch control valve is, and at the same time, the adjustment optimization instruction OP1zR=OP1z*(-1) for the third upper front gas branch control valve.

[0034] In order to achieve faster and more accurate adjustment, the difference between T1Lavg and T1Ravg is divided into four sections. The first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius. The proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c]. When the difference between T1Lavg and T1Ravg is in the first section, [a, b, c] = [1, 0.8, 0]; when it is in the second section, [a, b, c] = [1, 1, 0]; when it is in the third section, [a, b, c] = [1.3, 1.1, 0]; when it is in the fourth section, [a, b, c] = [1.4, 1.1, 0]; thereby obtaining different adjustment instructions OP1z, that is, different adjustment amounts.

[0035] The adjustment methods of the other three groups of burners are the same and will not be repeated here.

[0036] Gas leveling for burners in the same group is based on Figure 3 The results of the optimization of the combustion of the same group of burners after gas leveling are superimposed on the automatic instructions of the gas branch regulating valve of the corresponding burner as an offset, and finally participate in the large closed-loop control loop of the combustion regulation with the main steam pressure as the regulation object.

[0037] Step 4: Leveling the gas of the burners on the same floor; take all the highly consistent groups in the first grouping method; read the temperature field information of each group; calculate the average value of the temperature characterization value on the left and the temperature characterization value on the right of each group. If the average values ​​of each group are consistent, no adjustment is made. If they are inconsistent, increase the gas valve of the burner group with a smaller average value, and decrease the gas valve of the burner group with a larger average value; repeat this step until all the groups in the first grouping method are adjusted.

[0038] In this case, the front upper and rear upper are groups of the same height, and the front lower and rear lower are groups of the same height. Here, the front upper and rear upper are used as examples for explanation. The front upper and rear upper contain a total of 6 burners, namely the first front upper burner, the second front upper burner, the third front upper burner, the first rear upper burner, the second rear upper burner and the third rear upper burner.

[0039] The temperature characterization values ​​of the first front upper burner, the second front upper burner, and the third front upper burner are averaged to obtain T1avg, and the temperature characterization values ​​of the first rear upper burner, the second rear upper burner, and the third rear upper burner are averaged to obtain T2avg. Compare T1avg and T2avg. If the two are inconsistent, the PID regulator will output the adjustment instruction OPC, which only indicates the adjustment amount and has no direction; if T1avg>T2avg; then the adjustment optimization instruction OPC1=OPC*(-1)for the front upper gas control valve, the adjustment direction is expressed by a negative value, that is, it is adjusted down, and at the same time, the adjustment optimization instruction OPC2=OPC*1 for the rear upper gas control valve, the adjustment direction is expressed by a positive value, that is, it is adjusted up; if T1avg is less than T2avg; then the adjustment optimization instruction OPC1=OPC*1 for the front upper gas control valve, and at the same time, the adjustment optimization instruction OPC2=OPC*(-1)for the rear upper gas control valve.

[0040] In order to achieve faster and more accurate adjustment, the difference between T1avg and T2avg is divided into four sections. The first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius. The proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c]. When the difference between T1avg and T2avg is in the first section, [a, b, c] = [1, 0.9, 0]; when it is in the second section, [a, b, c] = [1.1, 1, 0]; when it is in the third section, [a, b, c] = [1.3, 1.2, 0]; when it is in the fourth section, [a, b, c] = [1.4, 1.2, 0]; thereby obtaining different adjustment instructions OPC, that is, different adjustment amounts.

[0041] In this way, the adjustment methods for the front lower burner and the rear lower burner are the same and will not be repeated here.

[0042] Step 5: Level the air volume of the burners in the same group; take a group of burner groups after the first grouping method; read their oxygen field information; compare the left oxygen value OiLavg with the right oxygen value OiRavg, if the two are consistent, do not adjust, if OiLavg is greater than OiRavg, then reduce the air volume valve of the burner in the group that intersects with the left burner group, and increase the air volume valve of the burner in the group that intersects with the right burner group; if OiLavg is less than OiRavg, then increase the air volume valve of the burner in the group that intersects with the left burner group, and reduce the air volume valve of the burner in the group that intersects with the right burner group; repeat this step until all burner groups in the first grouping method are adjusted; this step is similar to step 4, changing the gas valve to an air volume valve, which will not be repeated.

[0043] The gas leveling of the burners on the same floor is also based on Figure 3 The combustion automatic adjustment shown in the figure needs to be put into use when the boiler combustion is automatically put into use. The result of the same-layer burner leveling combustion optimization is superimposed on the automatic instruction of the same-layer operator as an offset, and then distributed to the corresponding branch pipe regulating valve, and finally participates in the large closed-loop control loop of combustion adjustment with the main steam pressure as the adjustment object.

[0044] Step 6: Level the air volume of the burners on the same floor; take all highly consistent groups in the first grouping method; read the oxygen field information of each group; calculate the average of the oxygen characterization value on the left and the oxygen characterization value on the right of each group. If the average values ​​of each group are consistent, no adjustment is made. If not, increase the air volume valve of the burner group with a small average value, and decrease the gas valve of the burner group with a large average value; repeat this step until all groups in the first grouping method are adjusted; this step is similar to step 5, except that the gas valve is changed to an air volume valve, which will not be repeated.

[0045] According to the analysis of boiler performance data and boiler combustion adjustment test, the optimal temperature field data corresponding to the boiler in different load sections are obtained. When the boiler can burn in the optimal temperature field condition, its air distribution is also in the best matching state. Measure and record the total air volume of the blowers on both sides of the boiler. In the actual operation of the boiler, the optimal total air volume model is used instead of the oxygen correction model; the optimal total air volume model inputs the boiler load and automatically outputs the corresponding optimal total air volume in the form of a linear broken line function. The optimal total air volume is used as the target value for controlling the output of the blower, thereby obtaining a more accurate air distribution instruction than oxygen correction, and then giving the basic opening instruction for the air volume adjustment of each layer of the burner; at the same time, the air supply PID regulator introduces the main steam pressure as a feedforward signal to ensure that the air supply volume is adjusted in time when the boiler operating conditions change, and maintain the stability of the ratio of air supply volume to gas volume.

[0046] The specific feedforward setting of air supply PID is to obtain the main steam pressure in real time, and use the numerical analysis algorithm to calculate the main steam pressure change rate per minute; judge whether it exceeds the preset value a0, or is lower than the preset value a1; if it exceeds the preset value a0, the feedforward gain coefficient K=Kmax, if it is lower than the preset value a1, the feedforward gain coefficient K=Kmin, otherwise the feedforward gain coefficient K=Knor; multiply the main steam pressure by the feedforward gain coefficient K as the PID feedforward signal, which acts together on the control output of the air supply fan inverter.

[0047] In this embodiment, a0=0.6, a1=0.2, and the feedforward gain coefficient K varies in the range of [0.1, 0.2]; when the main steam pressure change rate per minute is greater than 0.6Mpa, K=Kmax=0.2, and when the main steam pressure change rate per minute is less than 0.2Mpa, K=Kmin=0.1, otherwise K=Knor=0.15.

[0048] The present invention is not limited to the above embodiments. Any technical solution formed by equivalent replacement falls within the protection scope required by the present invention.

Claims

1. A combustion optimization control method based on boiler CT technology, characterized in that: The steps include: Step 1: The first grouping method: group the burners located on the same furnace wall of the boiler and with the same height into one group; The second grouping method: divide the burners into a left burner group and a right burner group with the center line of the front-to-back direction of the boiler as the axis; Step 2: finding the intersection of each group after the first grouping method in step 1 and each group after the second grouping method; collecting the temperature field information and oxygen field information of the burner area in the obtained intersection through the boiler CT system; Step 3: gas leveling of burners in the same group; take a group of burner groups after the first grouping method; read its temperature field information; compare the left temperature characterization value TiLavg with the right temperature characterization value TiRavg, if the two are consistent, do not adjust, if TiLavg is greater than TiRavg, then reduce the gas valve of the burner in the group that intersects with the left burner group, and at the same time increase the gas valve of the burner in the group that intersects with the right burner group; if TiLavg is less than TiRavg, then increase the gas valve of the burner in the group that intersects with the left burner group, and at the same time reduce the gas valve of the burner in the group that intersects with the right burner group; repeat this step until all burner groups in the first grouping method are adjusted; Step 4: gas leveling of burners on the same layer; take all highly consistent groups in the first grouping method; read the temperature field information of each group; average the temperature characterization value on the left side and the temperature characterization value on the right side of each group; if the average values ​​of each group are consistent, no adjustment is made; if they are inconsistent, increase the gas valve of the burner group with a smaller average value, and decrease the gas valve of the burner group with a larger average value; repeat this step until all groups in the first grouping method are adjusted; Step 5: Leveling the air volume of the burners in the same group; take a group of burner groups after the first grouping method; read its oxygen field information; compare the left oxygen value OiLavg with the right oxygen value OiRavg, if the two are consistent, do not adjust, if OiLavg is greater than OiRavg, then reduce the air volume valve of the burner in the group that intersects with the left burner group, and at the same time increase the air volume valve of the burner in the group that intersects with the right burner group; if OiLavg is less than OiRavg, then increase the air volume valve of the burner in the group that intersects with the left burner group, and at the same time reduce the air volume valve of the burner in the group that intersects with the right burner group; repeat this step until all burner groups in the first grouping method are adjusted; Step 6: Level the air volume of the burners on the same floor; take all highly consistent groups in the first grouping method; read the oxygen field information of each group; average the oxygen value characterization value on the left and the oxygen value characterization value on the right of each group. If the average values ​​of each group are consistent, no adjustment is made. If not, increase the air volume valve of the burner group with a small average value, and decrease the gas valve of the burner group with a large average value; repeat this step until all groups in the first grouping method are adjusted.

2. The combustion optimization control method based on boiler CT technology according to claim 1 is characterized in that: In step 3, the gas valve that is adjusted up and the gas valve that is adjusted down at the same time are adjusted by the same amount, but in opposite directions.

3. The combustion optimization control method based on boiler CT technology according to claim 2 is characterized in that: In step 3, a PID regulator is used to adjust the gas valve; the difference between TiLavg and TiRavg is divided into four sections, the first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius; the proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c], when the difference between TiLavg and TiRavg is in the first section, [a, b, c] = [1, 0.8, 0]; in the second section, [a, b, c] = [1, 1, 0]; in the third section, [a, b, c] = [1.3, 1.1, 0]; in the fourth section, [a, b, c] = [1.4, 1.1, 0].

4. The combustion optimization control method based on boiler CT technology according to claim 1 is characterized in that: In step 4, the gas valve that is adjusted up and the gas valve that is adjusted down at the same time are adjusted by the same amount, but in opposite directions.

5. The combustion optimization control method based on boiler CT technology according to claim 4 is characterized in that: In step 4, a PID regulator is used to adjust the gas valve; the difference in average values ​​is divided into four sections, the first section is greater than 0 and less than or equal to 10 degrees Celsius, the second section is greater than 10 and less than or equal to 25 degrees Celsius, the third section is greater than 25 and less than or equal to 40 degrees Celsius, and the fourth section is greater than 40 degrees Celsius; the proportional coefficient, integral coefficient and differential coefficient of the PID regulator are set to [a, b, c], when the difference in average values ​​is in the first section, [a, b, c] = [1, 0.9, 0]; when it is in the second section, [a, b, c] = [1.1, 1, 0]; when it is in the third section, [a, b, c] = [1.3, 1.2, 0]; when it is in the fourth section, [a, b, c] = [1.4, 1.2, 0].

6. The combustion optimization control method based on boiler CT technology according to claim 1 is characterized in that: According to the analysis of boiler performance data and boiler combustion adjustment test, the optimal temperature field data corresponding to the boiler in different load sections are obtained; when the boiler can burn within the optimal temperature field conditions, its air distribution is also in the best matching state; the total air volume of the blowers on both sides of the boiler is measured and recorded, and in the actual operation of the boiler, the optimal total air volume model is used instead of the oxygen correction model; the optimal total air volume model inputs the boiler load, and automatically outputs the corresponding optimal total air volume in the form of a linear broken line function, and uses the optimal total air volume as the target value for controlling the blower output, thereby obtaining an air distribution instruction that is more accurate than oxygen correction, and then giving the basic opening instruction for the air volume adjustment of each layer of burners; at the same time, the air supply PID regulator introduces the main steam pressure as a feedforward signal to ensure that the air supply volume is adjusted in time when the boiler operating conditions change, so as to maintain the stability of the ratio of air supply volume to gas volume.

7. The combustion optimization control method based on boiler CT technology according to claim 6 is characterized in that: The specific feedforward setting of air supply PID is to obtain the main steam pressure in real time, and use the numerical analysis algorithm to calculate the main steam pressure change rate per minute; determine whether it exceeds the preset value a0, or is lower than the preset value a1; if it exceeds the preset value a0, the feedforward gain coefficient K=Kmax, if it is lower than the preset value a1, the feedforward gain coefficient K=Kmin, otherwise the feedforward gain coefficient K=Knor; multiply the main steam pressure by the feedforward gain coefficient K as the PID feedforward signal, which acts together on the control output of the air supply fan inverter.

8. The combustion optimization control method based on boiler CT technology according to claim 7 is characterized in that: a0=0.6, a1=0.2, the feedforward gain coefficient K varies in the range of [0.1, 0.2]; when the main steam pressure change rate per minute is greater than 0.6Mpa, K=Kmax=0.2, when the main steam pressure change rate per minute is less than 0.2Mpa, K=Kmin=0.1, otherwise K=Knor=0.15.

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