| Industrial processes such as steel-making produce large amounts of high-temperature particles,the temperature of which is as high as 900 ℃.If this high-temperature waste heat can be effectively recycled,it is of great significance for high-energy-consuming companies to achieve energy-saving and emission reduction.Therefore,this paper proposes a moving bed type high-temperature particulate heat recovery device,which uses the principle of moving bed to allow the cooling air and the high temperature particles to flow in countercurrent and achieve high-efficiency waste heat recovery and utilization.A combination of numerical simulation and experiment is used in the paper to study the influence of the device’s structural parameters and process parameters on particle flow and heart transfer characteristics of the particles.Thesis includes the following main content:Ⅰ.Comparing the advantages and disadvantages of wet heat recovery and dry heat recovery methods of steel making slag,analyzing the development status of dry heat recovery,and referring to the principle of moving bed in chemical industry,a moving bed type dry high-temperature slag particle waste heat recovery device is proposed.Ⅱ.Using slant test,collision test and pull test to determine the contact parameters between particles,particles and steel plates.A small particle flow experimental platform was set up on its own,and the CCD high-speed camera was used to capture the trajectory of the particles.Compared with the simulation results of the EDEM software,the accuracy of the experimentally determined parameters and the feasibility of the EDEM model were verified.Ⅲ.Using EDEM for numerical simulation,study the effect of internal distribution plate structure parameters(D.θ,h/H,w/W)on particle flow,and determine the primary and secondary relationship that influences particle flow:D>h/H>θ>w/W.The dimensions of the non-stacked distributor plate are:D = 30 mm,θ = 76°,h/H=0.1,w/W=0.75.Ⅳ.To design and build an experimental platform for the small particle heat recovery unit independently,and experimentally study the heat transfer characteristics between particles and air.The experimental results show that when the particle mass flow rate is 0.04 kg/s,the air volume flow rate is 108 m3/h,and the particle diameter is 5 mm,4 mm,3 mm,and 2 mm,the heat recovery rate increases for each particle diameter decrease of 1 mm.1.89%,1.32%,1.03%,indicating that as the particle diameter decreases,the heat recovery rate of the particles increases,but the increase rate slows down;the particle mass flow rate is 0.04 kg/s,the particle diameter is 5mm,and the air volume flow rate is 108 m3/h,135m3/h,162 m3/h,and 189 m3/h,when the air flow rate increases by 27 m3/h,the heat recovery rate increases by 4.49%,3.08%,and 2.31%,respectively,indicating that with the increase of air flow rate,the heat recovery rate of particles increases,but the increase gradually decreased.Ⅴ.The CFD-DEM bidirectional coupling method was used to calculate and analyze the influence of process parameters(particle diameter,particle mass flow,air volume flow,and proportion of particles of different diameters)on the heat transfer characteristics of high temperature particles.The following conclusions can be drawn:Reduction of particle diameter can increase the heat recovery rate of pellets and the air outlet temperature,but with the decrease of particle diameter,the increase will be slower;increase the mass flow of particles,the air outlet temperature will rise,the increase will be slow,and the heat recovery rate is reduced and the reduction rate is gradually increased.When the air volume flow rate is increased,the air outlet temperature is decreased,but the decreasing speed is slowed,the heat recovery rate of the particles is increased,and the increase rate is gradually slowed down;the proportion of small and medium-diameter particles in the non-uniform particles is higher,which is more favorable for increase air outlet temperature and particle heat recovery. |
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