multiproduct pipeline interface cut ( Diesel/Jet)

[smartic]

I would like to have expert advice for the procedure or best practice to handle the multiproduct pipeline interface at terminals. Specifically, at what point during the receiving of diesel/jet fuel interface we should divert jet fuel to it dedicated storage tanks. We receive jet fuel and motor Diesel through 30-inch pipeline from refinery that is 500 KM away. the Jet fuel is stored, settled and certified at the terminal before transferring to Airport depot. Our practice is to make the interface cut based on jet density, so that jet fuel is diverted to jet tanks after density matching the source density through online pipeline densitometer and manual density. The difficulty we have that the density matching ( delta density = 0 between the source tank density at refinery and in-plant measured density) can’t be achieved unless continue receiving at interface tank till delta density = 0 which takes long time and losing the quantity of jet fuel. This practice is used to ensure no diesel is received at jet tanks and consequently impact the jet properties, e.g. Freezing Point. I have read some industrial standards, like JIG 1530, but I am not sure of what is the specific density point where the jet should be diverted to its tanks. Also, I came across the terminology of “clean cut” but I am also not sure what does it refer to. Moreover, I read some procedures that allow +/- 3 digits of density variation from the source density to start receiving at jet tanks, still I am not sure if it is accepted and will not impact the jet properties.

I appreciate expert advice and sharing industrial practices.

 

[RVAmeche]

For multi product pipelines it isn't unusual for there to be slugs of water separating the products. Would your system allow that type of delivery?

 

[LittleInch]

RVA,

It is very UNUSUAL to introduce water into the separation of products. I've never heard of this practice. The risk of contamination, especially for Jet fuel is far too high, not to mention any corrosion issues and water becomniog trapped in pipework etc.

It's been a while since I was a tthe sharp end for jet fuel delveries and the pipelines I was used to were quite a bit shorter and not as big diamter, hence the volumes of the interface were much smaller.

If you are receiving direct into storage tanks at an airport then you really can't take chances. The quality manuals for the transporting companies will tell you what is acceptable or not.

It's not easy to comment on this as there are too many items which are location specific.

I would need to see what the clean cut is in terms of the rest of the paragraph to be clear as it could mean a few different things.

but I understand the point - when does your interface finish and when do you open the manifold valve. Really takes judgement and experience. You could start taking samples of the later stages of the interface and then seeing if they pass the tests for aviation when mixed with the final product.

But you really can't mess about with aviation if this is then going straight into a plane. Normally I've seen this sit in tanks for testing then go in dedicated lines to the airport tanks where they do a final quick inspection before it goes on the plane.

Will be interested to see what others do.

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

 

[RVAmeche]

Ah, you didn't mention it was going straight to aircraft. For pipeline receipt there is typically bulk storage tanks and then operating tanks, and there are sufficient numbers of tanks w/ sufficient volumes to allow the water to settle and be drawn off.

Note UFC 3-460-01, the US military petroleum design guide, Chapter 6 (Interterminal and Installation Pipelines) states that fuel segregation with suitably treated water is acceptable.

Depending on the facility and operation, they may be additional filter/separator vessels between the different stages to extract the water used to segregate the fuel.

 

[1503-44]

30" pipe is difficult to connect directly to aircraft.
In any case I would avoid deliberately mixing in any additional contaminates.
A "clean cut" is made after the entire interface passes the densitometer and tee outlet and a bit of pure trailing product is through the cut valve on the way to the interface tank. A "dirty" cut is made while there is still interface mixture passing the densitometer, but when the mixture has reached an acceptable level of contamination, which can be safely dilluted into the receiving tank with no ill effect by the time the tank has been filled with the following pure product.