Thermal insulation performance of pipe joint coating in permafrost regions

Pipeline construction in permafrost regions is completed in cold environment. Rigid polyurethane insulation tile can effectively eliminate foaming under low temperature, but it also brings low working efficiency and poor thermal insulation performance. In this regard, silica aerogel insulation blankets and polyethylene foam are incorporated into the joint coating to improve construction efficiency and thermal insulation performance. Thermal conductivity, heat flux and external temperature distribution were analyzed for three kinds of joint coating structures at different temperatures of working pipe. The results show that the rigid polyurethane with thickness of 115 mm has the lowest thermal conductivity and heat flux. Silica aerogel insulation blankets can effectively improve the temperature distribution on outer surface. With superior performance, the compound insulation structure with polyethylene foam and silica aerogel insulation blankets can satisfy project needs. It can be used for pipe joint coating in cold environment.