| The Coal-fired boiler is mainly used in our country.However,the distribution of coal resources is uneven and the use cost is high,leading to the fact that most power plant boilers have to burn low-quality coal,which has a great impact on the safe and stable operation of boilers.Therefore,coal burning with different coal characteristics has become the main factor affecting the combustion process of the boiler.Based on the routine experimental analysis of pulverized coal,this project uses numerical simulation method to study the influence of coal quality on the combustion process of a 203 5t/h Ultra-supercritical tangentially fired boiler in a power plant,which can improve the efficiency of coal combustion and optimize the boiler running has a very important meaning.This paper briefly introduces the structural characteristics of tangentially fired boiler and many problems such as the selection of coal in actual operation.Then it introduces the mathematic and physical models and theoretical basis for numerical simulation of pulverized coal combustion in detail.And finally highlight the simulation of 2035t/h ultra-supercritical tangentially fired furnace combustion conditions,the use of pretreatment software Gambit in Fluent software.The furnace model is meshed and the boundary conditions are set according to the given parameters of the power plant.The appropriate mathematical physics model is selected,and the temperature field,velocity field,gas component field and pulverized coal particle trajectory and so on are achieved.The results of the simulation are analyzed in detail,and the characteristics of the flow and the temperature distribution of the airflow in the ultra-supercritical tangentially fired boiler are obtained.And further analysis shows that Calculation coal 2 is the highest temperature,because the Calculation coal 1 contains the highest moisture content,less carbon content and the lowest calorific value,while Calculation coal 2 contains the minimum moisture,higher volatile content,easier.On the other hand,when the Calculation coal 2 is burned and calculated,the boiler can use the most heat,but its outlet flue gas temperature is relatively high compared with the Design coal type,and the heat loss is larger.Among them,the calculated coal type 1 and the calculated coal type 2 are the mixed coal with bituminous coal and lean lean ratio of 8:2 and 6:4,respectively.The accuracy of the simulation results is verified by comparing with the actual operation data of the power plant,and the feasibility of the calculation method of this project is proved.It is instructive for the selection of coal in the power plant and the optimal operation of the boiler. |
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