13 replies to this topic

[lokesh_09]

Dear all,

How to achieve 0.5 vol% BS&W content in the final stage of crude that goes to cargo tank by specifying carry over in 1st stage(HP) and 2nd stage(LP) separation in hysys simulation

Thanks in advance

Regards,
Lokesh

[chemtan]

Dear Lokesh,

Understand that people reading this thread dont have the background knowledge that you have when you posted the thread. Can you be please more informative?

Please provide:
Drawings (Sketch, PFD).
Stream composition.
Any other info that you think is required for a person to understand your problem.

[Padmakar Katre]

Dear,

If you are modelling Desalter as a three phase separator (real separator in Hysys) then the results would be non-reliable.Have you defined slt contents and all. As far as my experience in Crude Refinery Modeling is concerned I have never seen the desalter modeling either in Hysys or in Pro-II. In this case you can give the actual inlet conditions and the outlet specifications for crude to a desalter vendor and get the clarifications and further information. Hope this clears your doubt if I had actually understood your query.

[Zauberberg]

If you want to model the existing separator as real separator, you could use the following option: double click on the vessel, go to the "Rating" tab, "C.Over Setup" option, and specify the quantity of each phase (vapor, light liquid, heavy liquid) in other phases/streams leaving the separator. That way you can adjust actual carryover. Was that your question?

[star@25]

Yes... We can adjust the individual phase carry over. But really how is that possible? One more thing is we are adding dilution water into the electro static treater. How can we achive in the treater. What is the relation ship between carry over & BS&W? Please clarity.

[Padmakar Katre]

Dear,
Just find the document which will guide you how to model real separator.

Attached Files

•  Real Separator Guide.pdf   431.52KB   1001 downloads

[Chellani]

CO option really doesn't model anything, it is simply fixing what you want at your desired conditions but how about those conditions which you haven't come across yet. It uses few empirical correlations which have no idea about what is your physicochemical system. We can try it for systems which haven't been studied by anyone but crude desalter is being studied since few years. If you don't have time to search / understand / study this sytem use CO.
Has anyone tried OLI Electrolyte FP for this? Here are few links to what OLI claims
http://www.google.co...&meta=&aq=f&oq=

[Zauberberg]

Predicting carryover rates is one of the most difficult things to be done, and entire research times are engaged for evaluating performance of different vessels/internals. It would be ridiculous to expect such solutiion from HYSYS - and to be done in a single step, on top of everything what I have just said.

C.O. option works in dynamic mode and it can be used in a smart way, e.g. once when you establish (measurement in the plant) carryover rates during steady-state conditions, dynamics can show you the trend of carryover during unsteady conditions. It can also give you a good indication of carryover intensity increase at higher vessel throughputs.

[daryon]

When we tak about BS&W with regard to HYSYS modelling we are really only talking about water in oil (WIO) of the processed crude. HYSYS does not model inorganic salts or sediment like sand or other particles. In addition to a crude oil BS&W spec (typicall 0.5%) there is often a salt specification in pounds per thousand barrels (PTB), a manual salt balance should be performed to ensure the salt spec is not exceeded in the processed crude oil.

In a typical 3 stage crude separation process WIO separation down to 0.5% BS&W is often achievable using simple gravity separators, for heavier crude oils or crude oils that form stable emulsions with water a electrostatic coalescer maybe neccessary or coalescing internals within the gravity separators. The 1st stage separator will perform bulk free water knock out and the exiting crude may have 30 to 10 % WIO. Performing Stokes' Law calculations gives you an idea of what size of droplet will settle out/ rise from each phase for a given separator residence time. I have seen bulk separation defined as separating all droplets of 150 micron diameter or larger from each phase.

The 2nd stage separator usally achieves a oulet WIO conentration of 15 to 5%, nd the third stage then achieves the product spec of 0.5 BS&W. Separation efficiency is dependant on temperature, differential density between oil and water, fluid viscosity, residence time, droplet diameter, etc. Its difficult to predict separation performance and this is best left to specialist internals suppliers (Zeta PDM, CDS, Hat Ltd.) there is no way HYSYS will predict this. The user must specify heavy liquid in light liquid carry over for each separator modelled. I usally do this on volume basis for the product stream of the separator.

[Dmitry]

Gentlemen,

I have a real 3 ph. separator. We used it during wells testing. I need make a model in Hysys of this separator. How can I specify carry over? I have all data, and volumetric flowrate of gas, water and oil after separator.

Regards,
Dmitry

[jatinder]

what is the minimum water loading for electrostatic coalescer? I have heard that it should be 10%. 

[dnrakesh2006]

For electrostaic coalscer better efficiency water content in the inlet feed should be min 5%v/v, if it is less than that makeup produced water is required at upstrem.

Edited by dnrakesh2006, 18 March 2013 - 11:01 PM.

[gegio1960]

what is the minimum water loading for electrostatic coalescer? I have heard that it should be 10%. 

 

please start a new thread for this subject.

regards

[junaid8942]

Hi Everyone! Carry over tab has the correlation option set(pro professorial /generic/ horizontal vessel) in which RR index, droplet size, mesh pad or vane pad can be given, go to this tab and specified this value;( such as when mesh pad are installed the carryover liquid size are reduced from 150 microns to 5 microns with 0.95 voidage).then Hysys self calculated the amount of Coarryover even in Dynamic mode.