Drainage problem of boiler superheater
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The superheater inlet and outlet headers of the boiler are equipped with drains, but they use two stop valves in series instead of a trap. The combined superheater drain system header is also connected in series to the drain expansion vessel through two stop valves. Please tell me, are these stop valves normally open or normally closed? ； If it is normally open, how to ensure that steam is not discharged? If it is normally closed, how to judge whether it is necessary to open the hydrophobic?
I haven't done any design work, but I think it's best to install a trap, and then drain the water from the trap and collect it centrally. The superheater must separate the water before it can generate superheated steam. Otherwise, it will only heat the water into saturated steam first. From your introduction, it should be that both stop valves are always open, otherwise the effect of immediate drainage will not be achieved. Your case involves centralized recovery and drainage. As long as there is no leakage at the final drainage point, there will be no problem. If you don't want steam to leak, you can only use a steam trap, and centralized recovery and drainage is generally not recommended.
Whether it is a low-temperature superheater or a medium-temperature superheater, the medium is superheated steam, and the temperature is above the saturation temperature. There will be no condensation water or wastewater during normal operation. The drain pipe joint on the header is used for water pressure testing and drainage during backwashing. It should be fully closed during normal operation. ； I understand that the two stop valves are connected in series to ensure no leakage. I don’t know about the situation on the centralized drain header.