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[Fr3dd]

Hello Guys,

 

Once again I'm here to hear (or read) your thoughts about some issue I'm dealing with now. I'm currently working in an upstram project which involves heavy-crude oil extraction (around 9 deg. API) with primary separation, dehydration and desalting before send it out of the facilities.

 

This heavy crude is going to be mixed with Light crude (around 36 deg. API) on the christmas tree in oder to ease its transport and processing. The processing path includes 3-phase separation, dehydration and desalting by washing with fresh water and using electrostatic coalescers.

 

I need to have a general idea of which need to be considered (general guidelines) for the start-up of the plant. My initial thoughts are early startup using only light crude oil and start-up of exchangers and other equipment.

 

My biggest concern is: after all the equipment is online, running with Light crude oil, we'll start ramping up the heavy crude oil flowrate; of course this needs to be done until reach the density/viscosity considered for equipment design.

- How can we monitor the density/viscosity of the mixed crude?

- Which kind of methods/instrumentation is recommendable for this (online measurement, sample testing)?

- What are the limitations of these measurement methods (considering extra-haviness and high viscosity)?

 

I would really appreciate your thoughts and your experience regarding these. Thanks in advance.

 

Fr3dd

 

[PingPong]

Is it possible to take a sample from the 9 ^oAPI crude before it is mixed with the 36 ^oAPI crude?

 

If so you can make blends of both crudes in different mixing ratios and measure the viscosity of each mixture at multiple temperatures in the lab.

 

In this way you can later on simply predict the viscosity from the flowrates of both crudes you are mixing, and the mixture temperature.

 

As you know the API gravity of both crudes you can also simply predict the mixture density from both flowrates and mix temperature.

 

Flowrate of heavy crude = flowrate of mixture minus flowrate of light crude.