[ Reply | Next | Previous | Up ]
From: james.arney@valero.com
Category: Safety
Date: 23 Dec 2004
We inject steam at 8.0 mlbs/h prior to the movement of the switch valve. Drum switch take 5-8 minutes. The early injection of steam prior to the switch valve movement is meant to more effectively open the cooling veins throughout the coked drum. Steaming is essential for proper cooling of the drum and hydrocarbon stripping to the main fract tower. I must say however that we most likely inject more steam than needed because the operators like to as it cleans the inlet line and head so less cleaning is needed after the unheading of the bottom head. In our case more steam means more of a impact to the main fract operation until the drum ovhd is diverted to the blowdown system. Now that you mention this it is time for us to revisit this and optimize the steam use...thanks