甲烷化废热锅炉管板温度场与应力分析

Temperature field and stress analysis of tubesheet of methanator waste heat boiler

甲烷化废热锅炉入口温度高达620℃,管壳程温差较大,管板承受内压与温差载荷双重作用。设计中管程选用内部衬里的冷壁结构,管板选用带折边的柔性薄管板结构。由于柔性管板应力状态复杂且各工况不同,难以用常规方法进行设计。基于有限元分析软件ANSYS,以入口端管板及其相连部件为研究对象,并取1/4整体结构及1/2壳程长度进行建模,对其进行温度场分析,得出管板各部分的温度分布,然后综合考虑压力与温度载荷的作用,分4种工况对管板进行详细的应力分析。温度场分析结果表明,各部位的实际温度均低于设计温度,绝热系统布置符合设计要求;应力分析结果表明,管板结构尺寸合理,各载荷工况下管板危险截面的应力强度均满足JB 4732—1995《钢制压力容器——分析设计标准》(2005年确认)要求。

The inlet temperature of methanator waste heat boiler was as high as 620 ℃,and there was a large temperature difference at tube side of the boiler.The tubesheet was working under the combination effect of thermal load and the pressure load at the same time.The lined cold-wall design was selected for the tube side and flexible thin tubesheet was adopted.The conventional design method could not be applied in the design because of the complicated stresses of tubesheets for each load case.With the FEA software ANSYS and on the basis of study of inlet tubesheet and associated connection parts,the temperature field was analyzed for the 1/4 part of the whole body and 1/2 part of shell side,and temperature distributions of different tube sheets were obtained.The stress of tubesheets of four load cases were analyzed in detail.The results of temperature field analysis show that the actual temperature at each location is lower than the design temperature,and arrangement of heat insulation system has met the design requirement.The results of stress analysis indicate that the tube sheet dimensions are appropriate,and the stress intensity of dangerous cross section of tube sheet at each load meets the specifications in JB 4732-1995 ＂Analysis and Design Standard for Steel Pressure Vessels （Confirmed in 2005） ＂.