antonio saura Cebrian
All these valves are called SP’s (steam purge) because they must be specified with steam purge. In the specific case of the SP-3 (in the FW design) that valve is located on the line that goe to the fractionator, There are units were have installed butterfly valves or gate valves. That valves can generally tend to stick (formation of coke in its internal, due to the loss of steam into the purge)
The main function of that valve is to help send more gas to the top of the drum to warm; close this SP-3 valve allow to force the hot vapors to the drum
As Clauss said in the new designs are being installed the valve that is called “ring valve,” prevent closing the valve completely (due its internal design, see velan page), almost all the new design (FW design) have installed ball valve in all this sytems like SP-1/2, also the valve going to the blowdown
I understand that problem is present from the initial startup of the unit, This may be due to poor design of the line of gases coming out of coke condensate drum (might be small) or that the blowdown system has a lot of pressure (less drive force)
What is the method or procedure to warm up the drum, I meant, for how long do you send the gas to the blowdown and to the fractionator. or how do you do to warm up the coke drum?
Excuse my English, Best Regards