CN-122015123-A - Gas boiler combustion optimization control method and system

CN122015123ACN 122015123 ACN122015123 ACN 122015123ACN-122015123-A

Abstract

The invention relates to the technical field of boiler combustion control, in particular to a method and a system for optimizing and controlling combustion of a gas boiler. The invention establishes a hierarchical closed-loop control logic by taking the oxygen content of tail flue gas and the concentration of NO x as dual feedback signals. Firstly, the standard of combustion is ensured by calibrating the target values of oxygen content under different loads, and secondly, in the control process, the air quantity is corrected according to the deviation of the oxygen content, and the FGR system is linked to perform special inhibition on NO x , so that the problem of 'failure in consideration' in the traditional control is solved. The method is particularly suitable for the open-loop controlled gas hot water boiler, and can realize the optimal air-fuel ratio through dynamic adjustment, thereby improving the thermal efficiency of the boiler to the maximum extent while ensuring low emission.

Inventors

LI XIUJUN
WEI PENGFEI
LI YUE
HUO QIZHI
WANG CHANGGUO
Wu Quanlai
ZHAO JINLONG
WANG JINGPENG
ZHANG TIANXING
YU JINLI
LIU YUXI
GAO QINGWEI
YAN JIANGFEI
YANG TONGLIN
LI ZHIQIANG
DING ZEPENG
HUANG HONGPING
XIAO TONG
ZHANG QIANG

Assignees

北京京能能源技术研究有限责任公司

Dates

Publication Date: 20260512
Application Date: 20260324

Claims (8)

1. The gas boiler combustion optimization control method is characterized by comprising the following steps of: S100, presetting a target value of oxygen content of tail flue gas, and determining a target value of NO x based on a newly built boiler atmospheric pollutant emission limit value table; s200, an oxygen sensor and a nitrogen oxide sensor are deployed, and real-time parameters of oxygen content and NO x concentration of tail flue gas are synchronously collected in the combustion process; S300, respectively comparing the oxygen content with a target value of NO x for the acquired real-time parameters of the oxygen content and the NO x concentration, and performing deviation analysis; S400, dynamically adjusting the air supply quantity based on deviation analysis, and controlling the smoke quantity through the existing nitrogen oxide suppression and regulation module; S500, dynamically adjusting a target value of oxygen content according to load change in a boiler combustion process, repeating the steps S200-S400, and controlling the flue gas amount.
2. The gas boiler combustion optimization control method according to claim 1, wherein the method for determining the target value of the oxygen content of the tail flue gas in S100 comprises: S110, determining a theoretical target interval of the oxygen content of the flue gas under rated load according to the type of the boiler, the form of the burner and the low-nitrogen emission requirement; S120, after the boiler is started in a cold state, setting the oxygen content to be higher than a rated load theoretical target interval in a hot state temperature rise low-load stage, and ensuring that CO is less than or equal to 100ppm and combustion is stable by adjusting the air quantity or the fuel gas/air ratio; S130, lifting the boiler load to 100% of rated load, and determining the lower limit and the upper limit of oxygen content by adjusting the air supply quantity in two directions; And S140, under 75% load and 50% load, gradually increasing the oxygen content by taking the rated load oxygen content as a reference, wherein the whole process takes CO less than or equal to 100ppm, NO visible black smoke, NO tempering/fire removal of a hearth and NO x as a core judgment standard, and the positive pressure stability of the hearth meets the discharge standard.
3. The method for optimizing and controlling combustion of a gas boiler according to claim 2, wherein the low load is 30% -50% load, and the oxygen content at the stage is 0.8% -1.0% higher than the theoretical target interval of rated load.
4. The gas boiler combustion optimization control method according to claim 2, wherein the determining method of the lower limit and the upper limit of the oxygen content in S130 includes: S131, gradually reducing the air supply quantity, adjusting the air supply quantity to be equal to or more than 100ppm, and determining the air supply quantity as the lower limit of the oxygen content; S132, gradually increasing the air supply quantity, adjusting to the condition that NO x exceeds the standard or the boiler efficiency is obviously reduced, and determining the upper limit of the oxygen content; S133, selecting an intermediate value of CO which is less than or equal to 50ppm, NO x which reaches the standard and combustion is stable between the lower limit and the upper limit of the oxygen content as a preset oxygen content target value under rated load.
5. The gas boiler combustion optimization control method according to claim 1, characterized in that: 75% load, wherein the oxygen content is 0.3% -0.5% higher than the rated load; 50% load, wherein the oxygen content is 0.8% -1.0% higher than the rated load.
6. The gas boiler combustion optimization control method according to claim 1, wherein the S300 specifically includes: Deviation analysis is carried out on the gas/air ratio: if the oxygen content of the actual tail flue gas is smaller than the lower limit of the oxygen content, judging that the air quantity is insufficient; if the oxygen content of the actual tail flue gas is larger than the upper limit of the oxygen content, judging that the air quantity is excessive; Deviation analysis was performed on NO x : if the actual concentration of NO x is larger than the target value, triggering the existing nitrogen oxide inhibition regulation mechanism; If the actual NO x concentration is not greater than the target value, the current regulation state is maintained.
7. The gas boiler combustion optimization control method according to claim 1, wherein the step S400 specifically includes: And (3) adjusting the gas/air ratio: When the air quantity is judged to be insufficient, the air quantity of the fan is increased, and the adjusting amplitude is positively related to the deviation value of the fuel gas/air ratio; When the air quantity is judged to be excessive, the air quantity of the fan is reduced, and the adjusting amplitude is positively related to the deviation value of the fuel gas/air ratio; NO x modulation: When the actual NO x concentration exceeds the target value, increasing the circulating smoke amount and inhibiting the generation of NO x ; When the concentration of NO x falls below the target value, the circulating smoke amount is gradually reduced to an initial state.
8. A gas boiler combustion optimization control system configured to execute the gas boiler combustion optimization control method according to any one of claims 1 to 7, characterized by comprising: The data acquisition module is used for acquiring tail smoke parameters and operation condition parameters of the boiler in real time; The controller is internally provided with a control model and is used for comparing the real-time parameters with target values and performing deviation analysis; the execution adjusting module is used for dynamically adjusting the air supply quantity according to deviation analysis and is connected with the existing nitrogen oxide suppression adjusting module in parallel to control the circulating smoke quantity.

Description

Gas boiler combustion optimization control method and system Technical Field The invention relates to the technical field of boiler combustion control, in particular to a combustion optimization control method and system for a gas boiler. Background The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art. With the increasing strictness of environmental regulations, particularly the increasing emission restrictions on pollutants such as nitrogen oxides (NO x) and carbon dioxide (CO), the combustion control technology of gas boilers is facing higher challenges. The traditional gas boiler control mode mainly depends on manual experience or simple proportion adjustment, and high-efficiency combustion and low emission are generally difficult to simultaneously achieve. In actual operation, combustion efficiency and pollutant formation are a pair of contradictors. Too small air volume (lack of oxygen) can lead to insufficient combustion, black smoke and carbon monoxide (CO) are generated, fuel waste and environmental pollution are caused, too large air volume (excessive oxygen) can take away a large amount of heat, the thermal efficiency of a boiler is reduced, and simultaneously, too high oxygen concentration and hearth temperature can promote the large amount of thermal NO x to be generated. Although the existing nitrogen oxide suppression and regulation module (such as a flue gas recirculation system, FGR) can effectively reduce NO x, the intervention time and the regulation depth often lack precise linkage with the real-time oxygen content change. Therefore, how to dynamically and accurately adjust the air supply quantity and the circulating smoke quantity according to the real-time load change and the smoke discharge parameters of the boiler so that the boiler always works under the optimal combustion working condition is a problem to be solved urgently. Disclosure of Invention The invention aims to provide an optimal control method and system for combustion of a gas boiler aiming at the defects. In order to solve the technical problems, the invention adopts the following technical scheme that the gas boiler combustion optimization control method specifically comprises the following steps: S100, presetting a target value of oxygen content of tail flue gas, and determining a target value of NO x based on a newly built boiler atmospheric pollutant emission limit value table; s200, an oxygen sensor and a nitrogen oxide sensor are deployed, and real-time parameters of oxygen content and NO x concentration of tail flue gas are synchronously collected in the combustion process; S300, respectively comparing the oxygen content with a target value of NO x for the acquired real-time parameters of the oxygen content and the NO x concentration, and performing deviation analysis; S400, dynamically adjusting the air supply quantity based on deviation analysis, and controlling the smoke quantity through the existing nitrogen oxide suppression and regulation module; S500, dynamically adjusting a target value of oxygen content according to load change in a boiler combustion process, repeating the steps S200-S400, and controlling the flue gas amount. Further, the method for determining the target value of the oxygen content of the tail flue gas in S100 includes: S110, determining a theoretical target interval of the oxygen content of the flue gas under rated load according to the type of the boiler, the form of the burner and the low-nitrogen emission requirement; S120, after the boiler is started in a cold state, setting the oxygen content to be higher than a rated load theoretical target interval in a hot state temperature rise low-load stage, and ensuring that CO is less than or equal to 100ppm and combustion is stable by adjusting the air quantity or the fuel gas/air ratio; S130, lifting the boiler load to 100% of rated load, and determining the lower limit and the upper limit of oxygen content by adjusting the air supply quantity in two directions; And S140, under 75% load and 50% load, gradually increasing the oxygen content by taking the rated load oxygen content as a reference, wherein the whole process takes CO less than or equal to 100ppm, NO visible black smoke, NO tempering/fire removal of a hearth and NO x as a core judgment standard, and the positive pressure stability of the hearth meets the discharge standard. Further, the low load is 30% -50% load, and the oxygen content at the stage is 0.8% -1.0% higher than the rated load theoretical target interval. Further, the method for determining the lower limit and the upper limit of the oxygen content in S130 includes: S131, gradually reducing the air supply quantity, adjusting the air supply quantity to be equal to or more than 100ppm, and determining the air supply quantity as the lower limit of the oxygen content; S132, gradually increasing the air supply quantity, adjusting to the