Are double valves, blind plates, or pipe caps required for the venting of oil pipelines in refineries? Are there any guidelines?
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Please help solve this issue, thank you.
What is a hat for? How can one still relax? However, what we use for blanking out is usually a double valve along with a blind flange, to prevent leaks that could cause contamination and waste
Completion: Code for Design of Metal Piping in Petrochemical Industries SH3012-2011 8.1.11 For combustible gas pipelines operating continuously, a double valve should be installed at the lowest point to ensure proper drainage; the liquid discharged should be sent to a closed system； Combustible gas pipelines should be drained only during startup and shutdown; a valve can be installed, along with a plug, pipe cap, or flange cover. When a shut-off valve is installed for draining on pipelines carrying flammable liquids and vapors, a plug, pipe cap, or flange cover should be placed at the end.
The specifications are not very clear, but on-site there are dual valves, including for low-point drain.
Toxic or flammable gases are hard to detect in the event of a leak in the valves; therefore, wire plugs or flanges are used.
Considering factors such as pressure and the medium, solid pipe plugs should be installed on the exhaust valves of pipelines for flammable liquids and gases； If it is a corrosive medium, a pipe cap can also be used ； Blind plates can be installed for special requirements. In some design institutes, the drain and vent valves for the sections connected directly to the process pipelines at pressures above 5 MPa are both double-block valves; flange covers are used for drains or vents in high-pressure areas, while thread plugs are used in low-pressure areas.
Your answer is exactly what I wanted; thank you.
Valves alone are not sufficient, as there is a high possibility of internal leakage in them. Using blind flanges for sealing is the appropriate approach, while plug valves are generally used for valves with threaded connections; threaded valves should not be used for chemical materials.