Structure Design And Analysis Of Aggregate Drying Pulverized Coal Burner Under Flame Control

The aggregate drying mostly uses fuel oil as fuel.With the shortage of petroleum resources and the rise of oil price in recent years,the fuel oil burner can no longer meet the economic requirements,while the pulverized coal burner has become a new demand due to its remarkable economy.Flame characteristics during pulverized coal combustion affect aggregate drying effect,pulverized coal combustion efficiency,and pollutant emissions,while the structural type of aggregate drying pulverized coal burner determines flame characteristics.Therefore,taking flame characteristics as evaluation index,this paper studies the structural design of aggregate drying pulverized coal burner.Based on the analysis of aggregate drying process and thermodynamic requirements,the behavior model and evaluation index of aggregate drying pulverized coal combustion are established,and the mapping rule between structural type of aggregate drying pulverized coal burner and flame characteristics is explored by combining theoretical analysis with numerical simulation.The specific research contents are as follows:1.Taking LB2000 type aggregate drying drum as the service object,considering the size and type of coal mill,and in view of the previous research of the research group,the type and structural parameters of aggregate drying pulverized coal burner are determined.2.The mapping rule between swirling aggregate drying pulverized coal burner and flame characteristics is explored.A primary cyclone and a secondary cyclone are sequentially added into the secondary air passage and the tertiary air passage of the direct-flow aggregate drying pulverized coal burner.Combined with the pulverized coal combustion mechanism and the aggregate drying process,the specific size requirements of flame length and diameter characteristics are determined.With the combustion efficiency of pulverized coal and NO emission as constraint conditions and the flame length and diameter characteristics as evaluation indexes,an orthogonal experimental design method is adopted to design an experimental scheme and carry out numerical simulation,the influence of different structural types of cyclones on flame characteristics is observed,and the structural optimization scheme of the swirling aggregate drying pulverized coal burner is determined.3.The mapping rule between flared aggregate drying pulverized coal burner and flame characteristics is explored.The flaring body is added on the basis of the optimal scheme of the cyclone type aggregate drying pulverized coal burner,and the test scheme is designed by orthogonal test design method and numerical simulation is carried out.The influence law of the structural parameters of the flaring type aggregate drying pulverized coal burner on the flame characteristics is analyzed,and the optimal scheme of the flaring type aggregate drying pulverized coal burner structure is determined.4.The mapping rule between blunt aggregate drying pulverized coal burner and flame characteristics is explored.Bluff body is added to the optimal scheme of cyclone type aggregate drying pulverized coal burner,and the experimental scheme is designed and simulated by comprehensive implementation method.The influence law of structural parameters of bluff body type aggregate drying pulverized coal burner on flame characteristics is analyzed,and the optimal scheme is selected.The optimal scheme is compared with the optimal scheme of cyclone type and flared type aggregate drying pulverized coal burner,and the reasonable structural type of aggregate drying pulverized coal burner is selected.The research results of this paper will lay a theoretical foundation for the development of aggregate drying pulverized coal burner.