Issues regarding the vent pipe behind the safety valve
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I have a question to ask! The vent pipe behind the safety valve is generally designed to lead directly to the roof, with a flame arrestor installed at the end of the pipeline! For which substances cannot the vent pipe behind the safety valve be connected directly to the atmosphere? It is necessary to install a large tank first, through which the gas can then be released into the atmosphere! Where does the rule come from!
TSG R0004-2009 Regulations on Safety Technical Inspection of Fixed Pressure Vessels, “8.2 Safety Accessories” (3) For pressure vessels handling explosive media, or media with an extremely high, high, or moderate level of toxicity, pipes should be installed at the discharge outlets of safety valves or rupture disks to direct the discharged media to a safe location where it can be properly handled; such media must not be discharged directly into the atmosphere；
There are many substances with extreme, high, or moderate toxicity; for example, methanol is one such substance. In the case of pressure reactions involving methanol, must the gas released by the safety valves be collected and treated?
During the emission of gases, a small amount of liquid may be present; therefore, a sedimentation tank is usually installed in the emission pipeline to allow this liquid to settle before it can be processed and recovered.
Methanol is indeed moderately hazardous. When overpressure occurs in the safety valve vent, the amount of leakage is relatively large. Methanol is involved in the reaction; you mean something like a reactor, right? Methanol may be discharged through the safety valve, and if people are in the vicinity of the discharge point, it is quite possible for them to inhale large amounts of methanol vapor. If there is a source of ignition near the exhaust outlet, it is possible to cause a fire explosion.
I would like to ask, if a square groove is installed, how is its volume calculated? And how thick should the vent pipe for that square groove be?
If water is present in the vent gas, a liquid separation tank must also be installed
Our safety valves are all connected to the flare system.
Non-toxic, non-flammable substances such as steam and water are released into the atmosphere
The key point is that I don’t have a torch system here; it can only be released into the atmosphere!
In cases related to emissions, the medium in question contains toxic substances and other materials whose direct discharge is prohibited by environmental and safety regulations; therefore, the safety valves on the pipelines carrying such materials must first be directed toward storage tanks, where pressure separation or extraction takes place before the materials can be burned in a flare.