关键词: 炼油化工企业, 大口径, 火炬管道, 管子, 管件, 法兰, 盲板, 阀门

Abstract: Combined with the engineering design experience of domestic large-scale oil refining and chemical engineering projects in recent years, the methods used in the design of large diameter carbon steel pipeline for flare system are introduced. Calculate the wall thickness and check the stiffness conditions of the pipe in combination with SH/T 3059—2012 or ASME b31.3—2020; large diameter steel pipes are recommended to be welded with normalized steel plates and supplied after overall stress relief heat treatment; the connection between the main pipe and the branch pipe generally adopts the combination of local opening reinforcement (the outer diameter of the branch pipe is less than half of the main pipe) and tee pipe fittings (the outer diameter of the branch pipe is greater than or equal to half of the main pipe); the tee is recommended to adopt the hot extrusion flanging hot forming butt welding process, and 100% radiographic inspection shall be conducted for the weld, and plug welding connection is not suitable; the flange design shall be matched with the equipment and valve; the large diameter blind plate is designed by GB 50316—2000(2008) or ASME B31.3—2020, and the split structure is recommended; large diameter non-standard valves should be selected according to the standard of conventional size valves for manufacturing, nondestructive testing and testing, but attention should be paid to valve end flange matching with pipe or equipment ends. The limitations of the current codes are summarized, and it is pointed out that attention should be paid attention to the material design, flexibility analysis and pressure test of large diameter pipeline under wet hydrogen sulfide condition.

Key words: refining and chemical industry, large diameter, flare system piping, piping, fitting, flange, blank, valve