| The industrial chain of iron and steel is long,the working procedure is complex,the resource consumption is huge,has been one of the key industries of air pollution in our country,and the sintering process is the main pollution of iron and steel industry.The traditional sintering process has a high energy consumption,severe pollution and low utilization rate of waste heat.Sintering flue gas circulation technology is a method to return part of the sintered flue gas through the flue gas seal cover to the top of the sintering machine and do sintering again,which can get a good energy saving and emission reduction.In the process of industrial practical sintering flue gas circulation system,the problems of uneven distribution of flue gas and uneven distribution of airflow on the inner surface of flue gas seal cover are common.This essay treats the equipment of the flue gas circulation system of 360m~2sintering machine in an iron and steel factory as the research object,uses the FLUENT simulation software to carry on the numerical simulation research to the flue gas distributor and the flue gas seal cover,analyzes the influence of the circulation system's structure parameter to the flue gas distributor and the flue gas seal cover flow field,and at the same time combines the evaluation index and makes sure the optimal flue gas distributor and the flue gas seal cover structure.Meanwhile,the essay also do the research of operating stability of the flue gas seal hood,the four sintering system parameters is as follows:flue gas flow rate,material height,negative pressure at the outlet of the bellows and porosity of the material layer.At last the main conclusions are as follows:(1)Based on the features of flue gas flow in flue gas circulation system equipment,the standard k-?two-equation turbulence selected,and the porous medium model is selected and its control equation is established for the material layer area,which lays a foundation for the numerical simulation of flue gas circulation system.(2)Based on the numerical simulation analysis of flue gas distributor with different structure,the causes of the uneven flow distribution of flue gas distributor are studied through the micro angle of velocity field and pressure field.Combined with the criterion of flow uniformity,the multistage variable diameter structure is obtained as the most uniform flue gas distributor structure.(3)The flow field of flue gas seal hood is numerically simulated by changing the inlet angle,inlet mode,inlet spacing and base height of the seal hood.The relative optimal smoke seal cover structure is obtained by analyzing the flow field inside the flue gas seal hood of different structures.The ratio of inlet,inlet spacing(L)and inlet diameter(D)k is 0.The ratio of flue gas seal base height(h)to flue gas seal cover height(H)is 0.25.(4)Through the numerical simulation and analysis of four sintering system parameters:flue gas flow rate,negative pressure at bellows outlet,material layer height and material layer porosity,the conditions of flue gas overflow produced by flue gas seal hood are defined,and the maximum flue gas flow rate in flue gas seal hood under different sintering system process parameters is obtained.(5)The relationship between flue gas circulation(Q)and flue gas seal cover pressure(P)under the process parameters of each sintering system was obtained by linear fitting.the field test of flue gas circulation and the pressure inside the seal cover were carried out and compared with the numerical simulation results.the error range was±20%in the acceptable range,which provided reference value for the actual flue gas circulation system regulation process. |
PDF Full Text Request