so, why do the refineries still do flare-off? (Rapaire)

I know you know really, but the flares are there for saftey. A pipe registers a big pressure drop, you shut it down and route it to the flare. If it's a false alarm, it's cost the comapny a bit of money. If it really has developed a leak, you've probably just prevented a huge leak, and stopped the plant blowing up. This generally a bad thing. repaet this for lots of scenarios...

You try very hard not to keep big tanks of intermediate products, so don't tend to have the capacity to store them. It's safer, and cheaper.Big tanks for feed stocks, and end products are another matter.*

BTW, I was studying Chemical engineering. Does it show?







* If you really care why, its simple. Products at either end of a process are often delivered/collected in bulk, so you need big tanks, which can be a safe distance from the main plant. Intermedite products occur in the middle of the process, so sticking a huge tank in the middle of the plant takes up valuable space, costs more money to maintain, and is at more risk from an accident than isolated tanks.