Tank Blanket Gas Requirement

[Berenger]

Hi all,

I am trying to estimate the flue gas requirement for a proposed plant. I have been able to determine all FG needed for all processes except tank blanketing purposes.

People have directed me to API 2000, but it doesn't give you the blanket gas needed. API 2000 is used to calculate vent sizes and flowrate.

Can anyone explain how I can estimate the daily blanket gas requirement for tanks? Currently, I am estimating the daily withdrawal from the tanks and using that volume as the requirement. For example, if 10 pounds of slop was pumped out a day, the blanket gas required will be 10 pounds converted into cubic ft. Same thing for amine and glycol (using amine and glycol make-up values from promax simulations). However, I am coming up with a small value - 60 cubic feet a day.

Is my approach right? Does the figure look reasonable for a 60 mmscfd plant? Make-up of amine is 1.12 lb/hr, glycol is 2.85 lb/hr, water is 144.53 lb/hr and slop is 0.55 lb/hr. Using their densities, I converted into cubic feet/day. Density for slop is 62.06 lb/cubic ft.

Thank you all for your help.

 

[JStephen]

If the flow rates are small relative to the tank size, I would think that thermal effects would contribute a lot of the blanket gas turnover?

 

[Compositepro]

One of the worst case situations is a nearly empty tank tank in the hot sun that suddenly gets rained-on.

 

[SJones]

Double posted from Chemical Engineering - red flag one and get it removed.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.