Research On Optimal Combustion Of Boiler For Large Units

In our country, the thermal power takes of a dominant position in the electricity supply. As the development of the power industry and the national economy, energy consumption is increasing sharply, and also brings a series of pollutant emissions. Energy saving and ejection decreasing is growing attention by the whole society.For our country's electric power industry, the phenomenon that boiler combustion can not reach the best state and even security problems is usual, because of coal changeable, equipment modification, variable load operation, and the interval cycle of thermal experiment is long, etc. So, it is urgent to optimize operation to improve the unit's security, economy and environmental protection. The conventional combustion adjustment experiment not only need a lot of human, materical and financial resources, and the cycel is long, income data has a lot of empirical and limitations. With the fast development of combustion theory, computer technology, computation combustion study and computation heat transfer theory, some commercial softwre of CFD has been development and application as well as, the numerical simulation technology is playing an increasingly important role in the power industry.This thesis does simulation research of boiler combustion under different operation conditions though FLUENT business software to one power plant boiler of 600MW supercritical unit.The temperature field, velocity field and concentration distribution of combustion production are calculted. By comparison and analysis, the best running state is found, and validated by experiment.Six different actual conditions are simulated by turning off different nozzle in this paper, and then it is that turning off the top nozzle is the optimal project the conclusion. Based on this, this paper studies that how do the change of Oxygen and different distribution of the secondary air affect boiler combustion and NO_X exhaust, and then the results show that keeping the Oxygen in 3.5 percent, and increasing the closed-coupled over-fired air and decreasing the seperating over-fired air properly can better meet economy and environmental protection requirement. This above results of this thesis can provide important value for optimize optimal of pulverized coal boilers.