热动力站蒸汽管道热膨胀异常原因分析及改进措施

Analysis and improvement measures for abnormal thermal expansion of main steam pipelines in thermal power stations

热动力站蒸汽管道由热膨胀引发的安全运行隐患将直接影响工厂的安全生产。针对热动力站易出现的管道、支吊架变形、过载热位移过大等异常问题,通过定量分析设计、安装及运行过程,评判造成管道热膨胀异常的关键因素,结果表明蒸汽母管刚性支吊架设计不合理、部分管系柔性偏大、安装过程支吊架性能降低或失效、运行过程缺乏有效处理措施是主要原因,采取优化支吊架、管道布置,达到管道系统“刚柔并济”,可有效消除热膨胀异常引起的安全隐患。经应力模拟计算,热动力站蒸汽管道系统热应力、热位移及设备推力显著降低,系统最大热应力由238.3 MPa降至176.23 MPa,原两处最大位位移量分别减少至17 mm和56 mm,对设备推力及力矩最高分别为10016.37 N和33032.37 N·m,最高降幅93.59%,提高了蒸汽管道系统稳定、安全及连续运行水平。研究结论可为高温高压蒸汽管道的设计、安装及运行提供一定的技术借鉴。

The hidden dangers in safe operation caused by thermal expansion of steam pipelines in thermal power stations will directly affect the safe production of chemical plants.In response to the common anomalies prone to occur in the thermal power station,such as pipe and support hanger deformation,excessive thermal displacement due to overload,and damage,a quantitative analysis of the design,installation and operation process is carried out to identify the key factors that may cause abnormal thermal expansion of the pipeline.The results indicate that the main steam header rigid support and hanger design is unreasonable,some piping systems have excessive flexibility,the performance of supports and hangers deteriorates or fails during installation,and the lack of effective measures during operation are the main reasons.Adopting a“rigid and flexible combination”design for the pipeline system can effectively eliminate the safety hazards caused by thermal expansion abnormalities.Through stress simulation calculations,the thermal stress,thermal displacement,and equipment thrust of the main steam pipeline system in the thermal power station have been significantly reduced.The maximum thermal stress in the system decreased from_(2)38.3 MPa to 176.23 MPa,and the original maximum displacements at two locations decreased to 17 mm and 56 mm,respectively.The maximum equipment thrust and torque are now 10016.37 N and 33032.37 N·m,respectively,with a maximum reduction of 93.59%.The stability,safety and continuous operation level of the main steam pipeline have been effectively improved.