架空蒸汽热网保温性能变化规律及恶化机制研究

Investigation of the trend and deterioration mechanism of thermal insulation of the overhead steam heating pipeline network

针对热力蒸汽管道的保温性能和热网管线散热损失特征随时间的变化规律及其恶化机理问题,采用对比法和焓降法对6组运行年限在5~14年之间的架空蒸汽热网的保温性能进行现场测试。测试结果表明,所测管道的保温恶化系数从运行5年的1.35升高到运行14年的1.73,管道保温性能随运行时间呈恶化趋势。其中,运行时间在8年以前的保温恶化系数以波动性特征为主,8年以后的则呈明显的上升趋势。保温材料导热系数和保温结构恶化是管道保温性能恶化的主要原因,其中导热系数的影响占比呈现出先增大后减小的趋势,最大为运行12年的管道,占比为53.74%。热网管线的保温性能恶化趋势与保温管道一致,并且局部踩踏和管件散热恶化会加剧管线的全程散热损失。

In view of the variation and mechanism of heat dissipation characteristics of thermal insulation pipes and heat network pipeline with time,the thermal insulation performance of 6 groups of overhead steam heat network with operating life of 5~14 years are tested by contrast method and enthalpy drop method.The test results show that the thermal insulation deterioration coefficient of the measured pipeline increases from 1.35 in 5 years of operation to 1.73 in 14 years,and the thermal insulation performance of the pipeline deteriorates with the time of operation.There is mainly characterized by volatility 8 years ago,but showed an obvious upward trend after 8 years.The deterioration of thermal conductivity of thermal insulation material and thermal insulation structure is the main reason for the deterioration of thermal insulation performance of pipeline.Among them,the proportion of the deterioration of thermal conductivity shows a trend of increasing first and then decreasing,and the highest is the pipeline for 12 years,accounting for 53.74%.The deterioration trend of thermal insulation performance of heat network pipelines is consistent with that of thermal insulation pipelines,and the deterioration of local trampling and heat dissipation of pipe fittings will aggravate the heat dissipation loss of the whole pipeline.