Numerical Simulation And Parameter Optimization Of Pulverized Coal Combustion In The Blast Furnace

Pulverized coal injection into blast furnace is a major technological progress in modern iron-making technologies,it has the advantages of saving energy and reducing consumption,making the blast furnace stable and smooth.In recent years,with the blast furnace coal injection ratio continues to increase,resulting in lower and lower burning rate of pulverized coal combustion.The excessive accumulation of unburned pulverized coal will lead to deterioration of permeability and liquid permeability of the stock column,so that the blast furnace cannot operate normally.Therefore,on the basis of ensuring blast furnace's trouble-free operation and energy saving,increasing coal injection ratio effectively has become a hot research topic in blast furnace iron-making field.The numerical simulation method is used to analyze the pulverized coal flow and combustion process in blast furnace area,then optimize the coal injection process parameters,which has an important guiding significance for improving blast furnace operating efficiency.Based on the characteristics of coal injection technology and based on fluid mechanics software,Euler-Lagrange method is used to describe discrete phase motion,Realizable k-? model,Two-Competing-Reactions model,Eddy-Dissipation model,Kinetics/Diffusion-limited model and P-1 radiation model were used to numerical simulation of pulverized coal combustion in the raceway,analyzed the influence of different operating parameters on the burnout rate of pulverized coal,and the key process parameters were optimized by orthogonal experiment method and effect value analysis method,finally applied the similarity theory to conduct the cold physical model experiment,which provides an experimental basis for the design and operation of a hot combustion field.In the study of the process of blast furnace coal injection combustion,the research contents include the following aspects:First,based on the actual conditions,establish the geometric models and mathematical models of the system,using the CFD numerical simulation to study gas-particle flow and combustion field in the raceway,using single variable method to analyze blast temperature,oxygen enrichment,pulverized coal injection rate and blast humidity on temperature and gas composition in the raceway.Secondly,using the extremum difference analysis and variance analysis method to select the optimal level of the four process parameters and analyze the significance.Find out the rule of index changing with factors and trends,combined with the effect analysis method to determine the best optimization conditions.Finally,based on the similar theory,design and processing a 1:15 scale narrowing model,carrying out the cold state experiment of the aerodynamic field inside the raceway,which can verify the correctness and reliability of the CFD simulation on the cold field,and analyze the experimental results.