Mixing of Crude oils with condensate in a pipeline 1

[LittleInch]

Hello All,

The issue I'm currently facing is how to show that a crude Oil pipeline, 24" OD, when it has a side stream of another crude oil (condensate) injected into it via a simple tee connection will mix effectively. My "understanding" is that after 1-2km at most, this continuous injection should be fully homogenised and the resultant mixture is a true mixture and not subject to separation or distinct flow patterns. Flow in the pipeline is fully turbulent and has a velocity around 1 to 1.5m/sec.

I've looked here and elsewhere for a more "technical" answer and something which has been undertaken which can be referenced (papers, data etc) but I'm struggling to find this continuous mixing issue as opposed to the more common interface issue. We could add an inline mixer, but this entails more expense and the injection is into a piggable part of the pipe line. The injection amount is around 10%, but we also need to determine if there is a maximum amount that can be mixed and how long (distance wise) it takes.

Any assistance gratefully received as I'm sure it must have been studied and looked at before as dilution or spiking of a more viscous Crude oil by a diluent is quite common.

Any more questions I'll try and answer.

Thanks, LI

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[dcasto]

As long as you have turbulent flow the two should mix very quickly, in under a kilometer

 

[LittleInch]

That's my thoughts as well, but I'm trying to find any technical papers, tests or calculations which back this up. Maybe I'm trying to prove something which no one has really tested, but either that or any other locations where this is successfully undertaken and then I can get public info or ask the relevant parties would be very useful.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[processeng2014]

There is some API specification or RP on crude oil sampling that does detail the amount of mixing that can be expected in piping given the fluid velocity. It also goes into things like how many elbows can be placed in the line to supplement not having a static mixer.

 

[LittleInch]

Any idea which one(s)? I've had a quick trawl and nothing jumps out at me at the moment, but I think you're on the right track, thanks.

Any experience of Dilbit mixing would be good if anyone can share this as the crude is very waxy.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Any particular reason you think waxy crudes mix well with condensates? Bitumens do tend to do that, but for example, waxy Uinta Basin crudes don't.

Learn from the mistakes of others. You don't have time to make them all yourself.

 

[BigInch]

"But there is one important difference between these waxy crudes (Uintas) and bitumen, which is that because of their paraffin wax content you can’t make them flow easily by diluting them with lighter hydrocarbons. That rules out the use of diluents such as natural gasoline or condensates like the Canadian’s use in their bitumen, to help waxy crudes flow in pipelines"

Learn from the mistakes of others. You don't have time to make them all yourself.

 

[LittleInch]

The issue is just a mixing one - the waxy bit is a bit of a red herring as the crude will be above the Wax Appearance temp. I was just making the point that I wasn't looking at bitumen type crudes. Whether it flows better or not is not the point of the exercise, it is to confirm that mixing will occur in a pipeline without the need for a mixer.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

That should help a lot.

Learn from the mistakes of others. You don't have time to make them all yourself.

 

[rotw]

It seems this person is a specialist in the field :

OCTAVE LEVENSPIEL

There is a paper from him on longitudinal mixing in pipe which I found here

http://pubs.acs.org/doi/pdf/10.1021/ie50579a034

Unfortunately I could access only the front page maybe this can be a reference.

 

[LittleInch]

Rotaryw,

Thanks very much, that looks like exactly what I need - am now tracking it down.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way