Calculate heating value at flare

[sunnyfriday]

Hello Experts,

how to calculate heating value at flare during equipment steam out operation. We have been observing flame-outs at flare during steam-out step in plant shutdown. Lowering the heating value below desired value (300 btu/scf or 12 MJ/m3) is probably cause for the same.

How to calculate heating value when 200,000 lb/hr 150# steam is diverted to Flare during shutdown?
Can we take credit for steam condensation in the system before it reaches the flare?
What is the impact on flare tip exit gas velocity?

please advise.

thanks.

 

[dcasto]

Since steam has 0 BTU/cf heating value, you can take 100,000,000 scfd of steam times 0 + Xamount gas scfd times 300 BTU/cf, then divide by sum of (100,000,000 + XAmount) to get new BTU/scf