In 2004 a gate valve (vapor gate valve-Velan) was installed at the Fractionator inlet for the sole purpose of isolating the Fractionator and Lt End unit from the drums, thus saving in downtime when gas freeing Fract and Lt End unit. The valve was recently inspected and found with coke in the gate guides which created a “design” concern since the valve did not close completely tight. Valve was installed in the horizontal position and has steam purge at the botom where the gate sits. My questions are: a) are there other installation similar to ours and if so, what type of installation they have regarding type of valve type (gate, ball, etc.), number of purge lines (location), any problems with their isntallation, remedies, etc. AP Maymi
You might consider a Delta Valve. I had heard that the Delta Valve was originally proposed for this service (isolation of the vapor line at the Fractionator). While evaluating whether or not to use the Delta Valve for this service, someone came up with the idea to use the Delta Valve for the Bottom of the Coke Drum.