Numerical Calculation Of Gas-Solid Heat Transfer In A Sinter Cooler And Its Application

The recovery of sintering sensible heat is one of the key tasks of China's iron and steel enterprises during the 13th Five-Year Plan.Based on the sinter cooler mode of waste heat recovery at domestic and foreign is the main form of sintering sensible heat recovery.The design and operation of the structure and operation parameters of the sinter cooler has been mainly focused on the cooling of the sintered ore,rather than on the recovery and utilization of sintered sensible heat.Therefore,the structure and operating parameters of the existing sinter cooler are not necessarily suitable from the viewpoint of efficient sensible heat recovery of the sinter.Based on this,the papers intends to use the numerical method to calculate the heat transfer process of the gas-solid in the sinter cooler from the point of efficient recovery of sintered sensible heat,and analyze the influence of the structure and operating parameters on the gas-solid heat transfer process.The typical structure and operating parameters for achieving high efficiency recovery and sufficient cooling of sintered sensible heat are proposed,which will provide the theoretical basis for tapping potentials.The main research contents,conclusions and innovations are as follows.(1)Based on the shortcomings of current numerical calculation of gas-solid heat transfer in sinter cooler,the viscoelastic force and inertial force coefficient,the comprehensive heat transfer coefficient of sintering layer,the sintering layer Dimensional numerical simulation model of gas-solid heat transfer was established by means of secondary development of UDF and embedded in COMSOL software,which was verified by self-made test-bed.(2)Focuing on the energy recovery and utilization of the cycle cooler-waste heat boiler-steam turbine-generator to obtain ideal power generation while ensuring the cooling effect of the sinter.The heat transfer medium to set the thermal parameters of the criteria,that is,to achieve greater enthalpy exergy of heat carrier.The temperature exergy and tons of power generation was monotonically increasing,the pressure exergy on the contrary.(3)At the same time,the air velocity in the lower part of the trolley is the largest,and the air flow is evenly distributed in the middle and upper parts.The air velocity is symmetrical with the center line of the trolley as the symmetrical axis,with the same height and velocity distribution was flat flow distribution,intermediate smooth and maximum,both sides gradually reduced.With the increase of the height of the bed,the static pressure of the sinter bed decreases in a quasi-linear manner,and the temperature of the sinter and the cooling air increases gradually.With the progress of gas-solid heat transfer in the sinter,the change of the air velocity field along the sinter direction is small,the pressure is increasing,the sinter and air temperature are decreasing,and the slope is decreasing.(4)The main influencing factors of the gas-solid heat transfer process in the sinter cooler machine are air inlet speed,material height and air inlet temperature according to the degree of influence.In the range of 394-424K,the enthalpy exergy of the air outlet increases with the increase of the air inlet temperature,and the increasing slope decreases.With the increase of the temperature from 1.12m to 1.96m,The enthalpy exergy of the air outlet increases with the increase of the height of the air inlet,and the increase of the enthalpy exergy increases with the increase of the air inlet velocity in the range of 1?3m/s.And the enthalpy exergy peak reached 1.21×108kJ/h in the vicinity of 1.5m/s.(5)For a domestic sintering machine 360m2,consider its operability and acceptability,the ideal parameters are,sinter cooler height of 1.96m,an increase of 40%than the existing;cooling air volume 296.4 thousand m3/h,than The existing enthalpy exergy of heat carrier is 1.4783×108kJ/h,which is 22%higher than that of the existing one.The output of ton ore is expected to reach 15.9?18.3kW·h from the existing 13?15kW·h,and the annual power generation is 12.0120 million kW h.