Ultra-long thermally insulated pipeline and forming method thereof

A forming method of an ultra-long thermally insulated pipeline, comprising the following steps:

• a):
• curling and welding a steel plate used for a working steel pipe into a pipe, and performing heat treatment to obtain a working steel pipe;
• b):
• making a phase change material into a spiral-ring shaped supporting frame on an outer wall of the working steel pipe, wherein the phase change material comprises:
• 20-30 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1;
• 50-100 parts by weight of elastomer;
• and
• 50-100 parts by weight of binder;
• c) curling a steel plate used for an outer sleeve steel pipe;
• wrapping, on an inner side of the steel plate, the working steel pipe with the outer wall provided with the spiral-ring-shaped supporting frame in the curling process, welding and sealing the working steel pipe into a sleeve with an annular cavity, and performing heat treatment on the sleeve;
• d):
• placing a plurality of rubber rings at two ends of the outer sleeve steel pipe for sealing, vacuumizing the annular cavity, and welding and sealing the ports of the outer sleeve steel pipe;
• and
• e):
• performing heat treatment on the welded and sealed pipeline.