Desulphurization Lance Numerical Simulation Of Thermal Stress Behavior Research

Desulphurization lance，a complex made up of metal core and refractory，is a key equipmentfor the process of hot metal pretreatment. As an intermittent injecting instrument, desulphurizationlance suffers from the thermal shock frequently during service, making the refractory crackedand thermal stress spalling. With the increasing of service time. At the end, the lance wasdestroyed by burn-through、bending and fracture finally, which lead to lance changed frequentlyand restricting the improvement of desulphurization production efficiency.According to the practical behavior of desulphurization lance, a fine model of typical unit(including anchorages) of lance was build by using FEM and testing thermal properties of lancerefractory at different temperatures. Then the temperature and stress field was analyzed byANSYS software. The effect of related factors on thermal stress distribution was alsoresearched.Finally; a new low-stress lance structure was invented and applied to the practice.The results show that: the temperature of lance changes obviously and the lance refractorybears tensile stress most of time during service; With the lance used times increasing, the thermalstress of outer layer refractories continuous growth; the thermal stress on bonding interface ofmetal core and refractory distribute unevenly, and the stress of refractory directly againstreinforcement tube is obviously more larger, which can making vertical crack in there.Thermo physical properties of lance refractory has great influence on thermal stress, and itis beneficial for improving thermal stress of lance when thermal conductivity is larger and elasticmodulus、thermal expansion is smaller. it can reduce thermal stress effectively to make bufferspace between core and refractory, and the optimal thickness of space is0.2mm; lance structurealso has comparatively large influence upon thermal stress, and both of invented structures canreduce the peak stress of refractory. According to the above influencing laws of related factors onthermal stress of lance, the improvements of refractory and new type lance were finished. Theresults of industrial test indicate that the service life of lance was extended122%.