Numerical Simulation Of Sintering Cooling And Analysis Of Waste Heat Recovery

Waste heat recovery is one of the important means of energy saving in sintering process.Waste heat recovery efficiency is related to the cooling capacity,exhaust gas temperature,exhaust gas volume distribution,air leakage rate of cooling machine and other factors.At present,there are some problems in the flue gas recovery system,such as severe air leakage,uneven air distribution in the supply system and improper air distribution,which lead to low efficiency of waste heat power generation system equipped in sintering process.In order to solve the above problems,air leakage rate measurement and laboratory basic research were carried out in the early stage of this paper.On this basis,a sinter cooling model of the same proportion as the industry was established to explore the influences of sinter layer thickness,running speed of the cart,introduction point of circulating hot air and other factors on the sinter waste heat recovery efficiency.In this paper,firstly,the A^#sintering belt cooling system of a steel plant was investigated and a comprehensive thermal test was carried out.According to the test data,the air leakage rate of the belt cooling system was analyzed and calculated,which was 47.5%.On this basis,a new method,"two-system coupling equilibrium method",which can simplify and improve the accuracy of air leakage rate test is proposed.On the one hand,the physical parameters of the sinter taken from the industrial site were measured,and the apparent density(3.618g·cm^-3),bulk density(1.628g·cm^-3),and porosity(0.55)were obtained.On the other hand,a cooling test bench with a ratio of 1:10 to the industrial site was built.The main structure included the upper cooling box and the lower trapezoidal bellows,and the flow resistance law of sinter material layer was obtained through resistance test.Finally numerical simulation method is applied to a single pallet and trapezoidal bellows as the research object,construct a three dimensional unsteady heat transfer model of porous media,the recovery of waste heat temperature and tons of ore recovery heat as the criteria,analysis of sinter material layer thickness(delta=1100?1500mm),car running speed(?=0.6?2.43m·min^-1),circulating hot air into the points(such as concentrated moved forward,cross forward scheme),and other factors impact on waste heat recovery efficiency.The results show that the waste heat recovery efficiency is the best when the thickness of the material layer is controlled at 1400mm.The operating speed of the trolley is controlled about1.88m·min^-1,and the waste heat recovery of tons of ore is the best.The optimal concentration of the introduction point of circulating hot air is to move forward.The waste heat recovery heat of tons of ore is 513,000k J/ton,and the corresponding generation capacity of tons of ore is about 11.8 degrees/ton,which is 17.7%higher than the heat recovery from the original introduction scheme of circulating hot air recovery point.