Vent gas water seal drum

[Pinnacle1]

We need to provide a water seal drum for a cold vent system. The drum size is 750 mm. Is it required to provide the manhole/ hand hole for the drum?

 

[EmmanuelTop]

Manholes are dictated by vessel inspection (entry) and personnel rescue requirements. You don't need a manhole for every pressure vessel.

API 521 (section 5.9) recommends handholes [DN 100 to DN 200 (NPS 4 to NPS 8) nozzles] to be present on the bottom of the drum to permit thorough cleaning. These nozzles should have DN 40 (NPS 1 1/2) or DN 50 (NPS 2) valves in the blind flange to permit complete draining of the vessels before opening. Read entire section 5.9 (API 521 6th edition) for complete information on other facilities that might be required (removal of hydrocarbons, drain, freezing protection etc.).

Also see

https://law.resource.org/pub/in/bis/S08/is.3133.1989.pdf

Dejan IVANOVIC
Process Engineer, MSChE

 

[georgeverghese]

Do you plan to use water as the seal fluid on a COLD vent? Can the cold vent gas temp be at or lower than 0degC ?

 

[Pinnacle1]

It's the relief vent from various safety valves and reaches the seal drum through a KO drum. We are planning to use cold water as sealing liquid. Max operating temp of SS seal drum is 113 Deg C. You may call it vent gas seal drum . Cold vent may be a misnomer.