Optimization For The Low No_x Emission Process Based On Particle Swarm Optimization

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,according to the boiler with Auto-adjustable blade coal distributor, a optimization modeling is proposed, whose object is NOx emission and whose independent variables are the number of nitrogen content in pulverized-coal and oxygen concentration of furnace outlet and a given load of unit and pulverized-coal concentration of every burner ports after some key factors which influence NOx formation had been analysed. Based on the model, an effective algorithm is developed to solve the problem.Particle swarm optimization (PSO) convergence's speed is fast, simple and easy to realize and only need to adjust to very a few parameters. But it is impossible that particle swarm optimization can be used to solve any problems, that is to say, we need to improve or modify this algorithm when using it to solve concrete problems. This paper has made deep research on PSO to solve constrained optimization problems in the foundation of the analysis of PSO, and the division strategy is added to combine with PSO, some relevant was put forward,that is Modified Particle Swarm Optimization with division strategy and double fitnesses(MPSODD). At last,the modified algorithm was applied to the optimal design of the low NOx emission process, the angle of Auto-adjustable blade coal distributor was found, Through the comparison of its optimizing result with the results by other optimization methods, the result shows MPSODD has gotten the most ideal optimization effect, and the feasibility and superiority of the modified PSO is confirmed. So it offers a new thought for guiding boiler optimization control.