Combustion Optimization Operation Of High Capacity Coal-Fired Power Station Boiler

Boilers are one of the three main frames of coal-fired generations. At present, coal-fired boilers on duty with 300MW load have problems of high emissions of pollutant and low combustion efficiency in China because of self-defects of equipments and lacks of excellent operating techniques. to improve boiler efficiency and save limited coal resources, reduce emissions of pollutant produced in process of firing coal are urgent to realize continuable development of energy resources in China as well as a problem to be overcome by electrical scientists and technicians.Focusing on the 330MW coal-fired boiler of No.7 unit of Jianbi power plant, this paper detailedly studied NOx formation mechanisms and some main factors influencing its emissions, and analized relations of controlling rules between reducing NOx emissions and improving boiler efficiency by combustion modification. At the basis of the above study, a combustion modification hot experiment was carried out. According to every experiment with different working conditions, characteristic relation between NOx emissions and some operating variables was analized. Some problems which exist in the boiler's current operating conditions are listed. And some suggestion is given.The utility boiler installation is huge. It has characteristics of multivariate, long lagging and nonlinear. It is almost impossible to predict outputs of combustion process in real time by some traditional physical and chemical models because of complication of burning pulverized coal in boiler's furnace. In order to solve this problem , the artificial neural network could be utilized. In this paper, a real time predicting model of NOx emissions and boiler efficiency is built by using BP neural network. Samples are datas aquired from the above experiment.Combining genetic algorithms using nonlinear optimization searching technology with the BP neural network model, some optimum operating plans under different coal was calculated. Results of high efficiency and low pollutant could be aquired if the boiler operates using the plan. The operation plan can either guide operators to operate the boiler or be combined with DCS suppling basis of model for achieving low NOx combustion optimization closed-loop operation.