V-jet pigging

[phuongnguyen]

Anyone has experience about v-jet pigging? When using double pig with V-jet followed, how would we deal with the pig moves down through riser, 1st pig can drop down and void can appear between two pig?
Many thanks

 

[1503-44]

I have not used a v-jet pig,

I think you might be talking about a run-away pig.
What conditions cause "drop down"? Can you explain more about this?

Is "drop down" something that you have experienced, or just a worry?

But I do not see how 2 of them could separate. They don't seem to allow for slippage, as long as you prevent a run-away pig conditions by controlling backpressure on the lead pig and keeping pumping rate up behind them.





--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

The V jet pig is a bypass pig so over time will gradually fall behind the initial pig as liquid is sprayed in front of it.

Really not sure how they keep the spray nozzle horizontal to spray upwards??

Why two pigs that close? Recipe for disaster. You need to explain this a bit more.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

I was thinking he was running two vjet pigs. If the lead is solid, then they would separate.

But why would a void form between them? The trailing vjet is packing the line ahead. It seems like a trailing void might happen, so just keep up the flow rate while holding backpressure on the leader.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."