February 9, 2005 at 9:55 am #4380
I’d like to find out what other cokers use for their cutting water isolation valve. We have an older coker that constists of 4 drums and a newer coker that consists of 2 drums. On our older coker we have manually operated resiliant seated ball valves. These provide reliable operation for about 2-3 years and then need to be replaced.
On our newer coker we have W-K-M Power Seal valves with a Limitorque actuator. These have been troublesome from a reliability point of view so we are considering replacing them with a different type of valve. [:@] Does anyone have just a regular gate valve in this service? If so, is there excessive leakage past it while decoking the other drum?
July 19, 2016 at 5:26 pm #21967
We are having problems with our isolation valves. In the last 3 years the maintenance increase a lot. There are in these isolation valves constant leaking. So, we are decoking a drum and the others drum are receiving water water leaking from the isolation valve.
We observe in these isolation valves in its internal like a erosion. Very hard erosion. Some part of the metal disappear. What is it ? Erosion by fines ? How can I measure this coke fines ? Is it corrosion ?
July 20, 2016 at 6:49 pm #22005
gary m pitmanParticipant
I am guessing you have the FLOWSERVE/TK valve 6″ x 2500 air actuator ball valve for your water isolation.
One thing that may help is using a sealant to prevent high pressure water from getting in the body. On the outside of the body there is a Lincoln head grease fitting that we pumped silicone sealant into.
I think that the OEM has something about this??
Packing the area around the ball helps to prevent coke laden high pressure water from entering the ball to body cavity causing erosion.
Some of the time the body is too eroded to rebuild.
It is a best practice to include this pumping of the sealant in a routine preventative maintenance package to prevent damage to the valve.
If the valves have been rebuilt, the tolerances may be incorrect on the seals around the ball to keep any water from getting into the body area.
There may be bull plugs in the body and someone will have to remove those and install the Lincoln head fitting. I can send some photo examples if you wish, contact me at the address below.
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