No replies to this topic

[Wilson]

We are having TVP issues at one of our crude oil batteries. In our process we combine NGL from our gas plant slug catcher with our light crude oil (42 API) before it enters a treater which runs at around 35 psi and 40-50C. Oil is then dumped to a 32ft 2000bbl 16 oz tank. Currently the inlet into the tank is only 926mm from the bottom and the tank is usually 10-15C and could be as cold as 0C.  As we are unable to get anymore heat out of our treater one potential solution that was proposed was to run a riser from this inlet to the top of the tank and have the oil from the treater splash out at a 45 deg angle. This should help twofold in that our product would not be cooled when entering the tank and also because of the agitation from the splashing.

 

Where I am having trouble is while this conceptually makes sense to me I am trying to assign some numbers to how much this may help propane breakout of solution and thus lower our TVP. In both cases the propane in solution would be above boiling point so is there a way to quantify how this reduction in pressure and increase in temperature would affect the breakout of propane from the crude oil. I have been looking into vapour pressures all morning and haven't been able to come up with an adequate solution. What I have determined is that I believe the vapour pressure of the propane will be approximately 100 psi different from the bottom (~100 psi @ 10C) to the top of the tank (196 psi @ 37.8C)  and the hydrostatics in the tank will be 6-9 psi at the current inlet level (vs ~0 with the riser installed).

 

My goal in this is to determine if the impact will be great enough to justify spending the money to install the internal riser.

 

Thanks!

 

Wilson

Attached Files

•  T-720 MARKUP.pdf   2.12MB   5 downloads

Edited by Wilson, 01 February 2017 - 05:12 PM.