How to flare only "excess" output?
Posted: Fri Jan 08, 2021 1:43 am
I have a steam cracker turning methanol into propene + residual, both of which are useful. I can buffer them to a point, but if one use dominates, the other will eventually starve. I'd like to flare off the "excess" output, which seems simple if I could cross-control two valves:
Valve1: flares propene if residual is empty
Valve2: flares residual if propene is empty
But I can't find a "circuit-controllable" valve, of the five valve types (inspector, non-return, overflow, top-up, convertor), and the flare stack is also not controllable. How do I solve this? I can't just use two overflow valves, because if neither output is consumed, both will flare and lead to waste.
Or maybe the answer is, use two overflow valves, but control the upstream input to the cracker? Or control the power to the cracker?
Thanks
john
Valve1: flares propene if residual is empty
Valve2: flares residual if propene is empty
But I can't find a "circuit-controllable" valve, of the five valve types (inspector, non-return, overflow, top-up, convertor), and the flare stack is also not controllable. How do I solve this? I can't just use two overflow valves, because if neither output is consumed, both will flare and lead to waste.
Or maybe the answer is, use two overflow valves, but control the upstream input to the cracker? Or control the power to the cracker?
Thanks
john