Heater outlet line

[Anonymous]

From: rambabu
Date: 26 Jul 2004

I am rambabu, from Reliance Industries Limited, Refinery division, India, Working as a process engineer in Delayed Coker. We are planning to go for expansion of coker from 150 KBPSD to 170 KBPSD. This question is regarding coker heaters. Is there any velocity / pressure drop / residence time criteria for the heater outlet line to coke drums? Ph (O): 0288-3010510

Transferred from the coking.local Discussion on August 16, 2004 by the coking.local administrator.

[Anonymous]

From:
Category: Safety
Date: 07 Aug 2004

Comments
The more you push thru the transfer line from the heater to the drum the greater the pressure drop. The greater the pressure drop the higher the pressure in upstream of the drum i.e. the heater tube. When the pressure is high in the transfer line and the heater tube this causes the velocities to go down and the residence time to go up and finally as the residence time goes up the coking in the tubes/transfer line goes up. Now there is an equalibrium that is reached with this -> as the DP goes up the back pressure goes up and the vel go down which then causes the DP to go down – a new equalibrium is reached.

Transferred from the coking.local Discussion on August 16, 2004 by the coking.local administrator.

[Anonymous]

From: Coker Squirrel
Date: 04 Aug 2004

As a rule of thumb, 6′ per second per coil is minimum flow velocity. Don’t know the velocity of the hater outlet line.

Transferred from the coking.local Discussion on August 16, 2004 by the coking.local administrator.

[Anonymous]

If you have a KBC heater programs you will be able to simulate this in conjuction with FRNC5.
 
SMistry

[Lucibar Davalillo]

In cokers always pay giving up something to increase throughput; it has been my way of running cokers. If heaters safety limits are not exceeded, then go for it. Typically Coke drums are the limitations, especially in latest designs where overdesign hardly gets to 110%. Also feedstock is getting worse and most likely will eat that extra 10%.
In summary, make sure maximizing your heaters and everything else, but watch closely your drums; you will recover faster from heater tubes fouling and even plugging, but coke drum foamover would be a killer.
Just my thoughts..
Lucky 

[Author]

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