Study On Mixed Modeling And Optimization Of NOx Emission And Efficiency Of Utility Boiler

With the increasingly stringent environmental requirements and the continuous increasement of coal price, coal-fired utility boiler operation is confronted with two requirements to reduce its operation cost and to lower its emission under the background of the power market reform of "separation of the power plant from the grid and bidding in the generation market". The high efficiency and low pollution combustion optimization technology is attracting more and more attention.In order to meet the requirement of high efficiency and low emissions in boiler operations, a mixed model is developed based on experimental data and combined with LS-SVM. This model uses the adjustable operation parameters of boiler, uses NOx emissions and boiler efficiency as the output, and achieves prediction of NOx emissions and heat efficiency. In the model, PSO is used to find the best parameters of LS-SVM, which is a difficult problem in practical application.Base on the above model, a optimization modeling is proposed, whose object is both of boiler efficiency and NOx emission and whose independent variables are the number of running coal pulverizers, coal fineness, flue gas temperature and furnace outlet oxygen. Then, the optimized NOx emissions and efficiencies are obtained by using MOPSO and compared with those by using weighting method. Results show that, reducing NOx emission is not always conflict with increasing efficiency, except that the operating condition doesn't have large optimization space. It is an unusual case to use MOPSO to optimize operation parameters of boiler in the field of boiler combustion optimization.Base on the work above, combined with OPC, a Guiding system for optimizing boiler combustion is developed with Visual Basic 6.0 and MATLAB 6.5,which is convenient for operators or technician to model and optimize utility boiler combustion.