Study On Improved Technology For Recovering Waste Heat From Fused Magnesia Based On The Spot Temperature Test

China is the world’s largest producer and supplier of fused magnesia. However, domestic process system of fused magnesia has not only fallen behind with serious waste of resources and energy, but has serious impact on the surrounding environment as well. Thus, developing a new method for energy saving from magnesite melting process will promote the sustainable development and enhance the international competitiveness of magnesium industry.The following technique:high temperature broken which comes from initial process of fused magnesia production system are denied by this article. The changes are based on the spot broken and temperature test. Based on the system energy saving and heat balance theory, a new waste heat recovery technology of fused magnesia is put forward. Through calculating the energy in the new process of fused magnesia production system does it show that1214kWh/t of heat the fused magnesia contains of every fused magnesia lump,6809.84Nm3/h of air flow is required by waste heat recovery chamber, reclaimed hot air can preheat magnesite from200℃to400℃. When magnesite is preheated to370℃, arc furnace can reach the energy saving target of14.06%. As fused magnesia products can save energy330kWh/t, the electricity of1.65billion kWh (1.32billion yuan) can be saved annual.Through preliminary design for the key equipment in the new technology, especially the waste heat recovery chamber with fin, a new method of round nozzle impinging jet is proposed, and a combination of continuous ventilation and intermittent ventilation air distribution system are also used in this new technology.Waste heat recovery process is numerically simulated and analysed by Fluent and Tecplot software. As simulation results of velocity field demonstrates that forced convection heat transfer by impinging jet increased wind speed near the wall obviously, not only the effect of convection heat transfer between air, fused magnesia lump and the fin are strengthened, but the temperature of outlet is increased as well. As the variation of temperature field demonstrates that the waste heat recovery chamber with fin can not only increase convection heat transfer area, shorten the crystallization time of MgO, optimize the crystal quality of fused magnesia, the maximum temperature of outlet finally receive453℃, but a theoretical basis for the new technology is provided as well.However, after the crystallization, the outlet temperature is gradually decreased with continously forced convection heat transfer. Also, it is difficult to maintain the outlet temperature at453℃. According to the simulation results, it can confirm that a combination of continuous ventilation and intermittent ventilation air distribution system is reasonable for the waste heat recovery chamber.