PRV Sizing References 1

[JAlton]

I am a relatively unsophisticated user who needs aid in determining the required capacity for systems found in general industry. I also need assistance in estimating pressure relief device adequacy of systems.

I am looking at systems which include ASME Sec. I, Sec. IV and Sec. VIIIs. Sec. VIII pressure vessels are the area where there is most need for this type of information. Other than overpressure limits, Sec. VIII offers no guidance on PRV sizing. My inquiries typically come from plant maintenance personnel who are changing the boiler burner from oil to natural gas or adding an air storage vessel to a plant air system.

Most of the new product standards, including ASME Code, do not offer guidance when systems are modified, expanded or rerated.

Can anyone offer suggestions?


J. Alton Cox

http://www.delucatest.com

 

[jay165]

Your first step should be to read and thoroughly understand API RP 520 and 521. The design of a pressure relief system is extremely complicated and requires engineering knowledge on many levels. I would urge you to hire a consultant who has experience in this area if you need help. In my opinion, relief and flare networks are one of the least understood and the most incorrectly designed systems in petrochemical or power generating facilities.

 

[meandmyostrich]

I had a similar problem sizing relief venting for fire engulfment of solvent storage vessels. I designed a spreadsheet from the calculations stated in API520. It gives an indication of vent size required, but does not take into account 2 phase flow, which is extremely difficult to model. For something as vital as pressure relief I would agree with jay165's conclusion, but if you would like a copy of the spreadsheet to identify whether your vents are in the right ball park please e-mail me and I will send you a copy.

 

[Tonylmiller]

I can assist you, but I do not think I can do it through this forum. Pressure relief valve sizing is just too complex. Contact me through the URL below if you would like some assistance.

Someone please let me know if this post is inappropriate.



Tony Miller
Cornerstone Engineering Group, p.c.

http://www.cegpc.com

 

[MortenA]

Tone: I think its OK.

My best advise (for mr. Cox) would be: Seek help - either inhouse or from a consultant (it could be Tony).

Best regards

Morten

 

[thorco1]

Visit CWFC.com/farris and register for the sizemaster program which will allow you to properly size the relief valves. This is one of the best programs available for relief valves.