| With the large-scale grid connection of renewable energy such as wind power and the increasing fluctuation of load at the power consumption end,thermal power units are facing more and more serious peak load regulation pressure.It is necessary to reduce the operation load of thermal power unit so that it can operate flexibly and stably and accept new energy power grid connection under deep peak load regulation condition.The problems of combustion deterioration and operation stability deterioration exist in the operation of boiler under the condition of deep peak load regulation,the method of combustion optimization not only has low cost,no need of new equipment and less manpower investment,but also has obvious optimization effect.The ratio of air to coal and the shape of air distribution are very important to improve the combustion stability and boiler efficiency,but the existing combustion optimization control system can only guarantee the correct proportion of the total amount of wind coal,It can not realize the flexible adjustment of air coal ratio and air distribution shape in the whole process of boiler operation.In this paper,the combustion optimization control is carried out from two aspects: precise control of the air coal ratio in the whole combustion process of the furnace and flexible adjustment of the air distribution shape,On this basis,a combustion optimization control scheme for pulverized coal fired boiler under variable load condition is proposed.The optimization plan is divided into five steps,they are parameter calibration,signal reconstruction,control optimization,combustion adjustment and evaluation feedback.Build some simulation modules for each optimization step and conduct online simulation.In order to realize the accurate calculation or adjustment of the parameters related to the boiler combustion,such as oxygen content,air volume,coal calorific value,flue gas flow,coal supply,air distribution shape and flame center height under different working conditions.In addition,the combustion optimization effect is evaluated on-line through the flue gas temperature module and boiler efficiency module at the furnace outlet.The data of THA,50%THA and 40%THA in No.3 boiler of JJ power plant are substituted into the simulation module,and the results are compared with the original data given in the boiler operation regulations,which proves the accuracy of the simulation module.This combustion optimization control system can be embedded in DCS of power plant to guide the combustion optimization adjustment in the process of deep peak shaving. |
