Regarding the connection between the main pipe and branch pipes
Thread Content
Dear Haihao friends! My project involves a pipeline with the line number PGV-9391103. The characteristics of this pipeline are as follows: the material is pyrolysis gasoline exhaust; its state is gas. The operating pressure is 0.001 Mpa, and the operating temperature is room temperature, with no insulation provided. The pipe material is 20# steel, and its pressure rating is 150 lbs, corresponding to pressure classes SHB3 and GC2. In the process piping and instrumentation layout diagram, there is a design feature where the main pipe is 6 inches in diameter, and the branch pipes are also 6 inches in diameter. The straight sections of pipe are inserted into the main pipe at an angle of 30° along its direction of flow; there are openings directly on the main pipe, and these openings need to be reinforced. Is such a design reasonable? What is the basis? Can reinforcement plates be used for pipes carrying flammable media? Why not design a 45° angled tee? As shown in the figure below
The pressure is very low; since it’s not a pressure pipeline, no reinforcement calculations are required – welding is sufficient.
Pipes with such low pressure don’t require any attention!
The only explanation for handling it in this way is to reduce the interference between the two streams of exhaust gases
1. It is permissible to use reinforcement plates for flammable and explosive media; generally, reinforcement plates should not be used in GC1 pipelines. 2. There is no essential difference between a 30-degree connection and a 45-degree connection for gases; both are used to minimize mutual interference, and this is the typical connection method used after safety valves. 3. The standard provides calculations for 45-degree and 90-degree reinforcement; 30-degree reinforcement is generally rarely used. Although the pressure here is very low, considering the equal diameter of the main pipe and branch pipes, as well as the fact that it is a flammable and explosive medium, reinforcement is definitely required in the design.
Thank you for your reply; the explanation was very professional and clarified the intent behind the design.
A torch pipeline should be installed, with the branch pipes connecting to the main pipe at an inclined angle; this is done primarily to reduce airflow interference and facilitate pressure release. Strengthening of GC2 pipelines is necessary
It’s a torch pipeline, so there’s no problem with this design