Numerical simulation on thermal deformation of water-cooling pipe for radiation screen in radiant syngas cooler
Coal gasification technology is an effective way to the clean and efficient utilization of coal,the entrained-flow gasification process with radiant syngas cooler(RSC)can effectively recover the sensible heat from high temperature syn-gas and improve energy utilization rate.The radiation screen adopted inside the RSC is not only keeping the overall struc-ture compact,but improving the heat transfer area greatly.In order to study the thermal deformation of the radiation screen in the RSC under gasification operating conditions,a three-dimensional radiation screen model is established by using the fluid-structure coupling principle to simulation analysis.The simulation results show that under normal operating condi-tions,the temperature of the whole water-cooling pipe reaches the maximum value at 5.30 m from the top.In the circum-ferential direction,the surface temperature of the pipe 1 closest to the center of the RSC is parabola distribution.Temperat-ure in the middle of the fire-facing side is the highest,and the maximum temperature difference between the fire-facing side and its back side reaches 60 K.Due to the cooling action of adjacent water-cooling pipe,the surface temperature of pipe 2-5 becomes bimodal distribution.The spatial arrangement has direct effect on the surface temperature distribution of water-cooling pipe.The local deformation of pipe 1 closest to the center of the RSC in water-cooling pipe without fixed is the largest,which is 5.20 cm.Maximum offset in π direction is 4.58 cm,far exceeding the pitch of water-cooling pipes,and the collision between water-cooling pipes is prone to occur.The overall deformation arises after water-cooling pipe is fixed.Maximum thermal deformation of water-cooling pipe with fixed is 3.28 cm,which is 36.9%lower than that of water-cooling pipe without fixed.The relative shift in the π direction basically disappears.Local deformation between the water-cooling pipe is smaller than the distance between the pipes.The occurrence of collision between water-cooling pipes is disappeared for the fixed action of the fixture.The changes of inlet syngas temperature and surface deposition affect the surface temperature gradient and deformation of water-cooling pipe with varying degrees,the offset direction is π/2 side of the water-cooling pipe.
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