摘要
立式热虹吸式的氯甲烷汽提塔再沸器在投用后短时间内发生换热管与管板连接处泄漏。热力分析表明,受传热面高热流密度和塔釜液位波动影响,换热管内汽液两相流不稳定并产生沸腾恶化,换热管壁温有明显波动,且分布不均。强度校核显示管子平均拉脱应力值高,壁温不均增加了部分管子拉脱应力,热应力冲击造成管孔结构设计和胀接质量存在欠缺的接头发生拉脱泄漏故障。提出采用三波膨胀节,改进管孔结构设计和制作工艺的技术措施。实施效果表明:设备未再发生换热管拉脱事故,稳定运行周期超过2.5年。
The tubes - tube sheet joint of vertical thermal siphon chloromethane stripping tower - reboiler was leakage in a short time. The analysis of thermal process showed that high heat flux and the fluctuation of liquid level in the tower bottom caused unstable flow of the steam liquid two - phase and boiling deteri- oration in the heat exchange tube. The temperature of tube wall was nonuniform distribution and change obviously. The strength check showed that the average pulled off stress of pipe was high, part pipes pulled off stress rised since nonuniform temperature distribution. The heat exchange tube joint was pulled off be- cause thermal stress impacted with the addition to the defect of tube pole structure design and tube expan- ding process. The technology improvement measures, using three wave expansion joint and improving the tube pole structure design and manufacture, was put forward. The result show the pulled off accidents of heat exchange tube has not occurred again, and the stable operation cycle extend to 2.5 years.
出处
《压力容器》
2013年第4期71-75,80,共6页
Pressure Vessel Technology
关键词
汽液两相流
膨胀节
热应力
结构强度
steam liquid two - phase flow
expansion joint
thermal stress
structure strength
