3 replies to this topic

[shubh]

Hey

I'm a ChemE B.tech undergrad, working on a project to model the Delayed Coker Unit using HYSYS.

What the HYSYS plugin should do is:
The input is a heavy hydrocarbon stream (vacuum residue) about which everything is known.
1)It should model the stream as a mixture of hypothetical component lumps.
2)Then, based on the hypothetical reaction kinetics of these lumps, and a reactor model for the coker unit, it should predict the composition of the outlet stream, in terms of lump compositions. (No other product is created, only the relative amounts of the lumps change in reaction)
3) Finally it should delump the outlet stream into the 50 or so components which the input stream was made of, and output properties such as composition, temperature, pressure etc.

I need:
1) A Lumping model for vacuum/atmospheric residues for delayed coking (i.e. Determine Lump compositions from stream compositions, reactions of lumps and kinetics, delump lumped products into components)
2) A reactor model for the delayed coking unit eg PFR, STR, 2Phase-PFR etc

Has anyone here done this kind of thing?
All help appreciated
Thanks

Edited by shubh, 31 May 2010 - 11:36 PM.

[Bharat Abhyankar]

Dear Shubh,
1) After defining the Assay, HYSYS will characterize it in Pseudo Components / Hypo Components.
2) It is well knows that high molecular weight hydrocarbons undergo thermal cracking reactions which can be modeled by 1st order reaction kinetics.
3) As part of your project you may try to model these reactions in PFR as residence time is also important in Coker.
4) If you need a ready made model of Delayed Coker, you may switch to Petro-SIM which has basic platform of HYSYS and built in Coker Model.

... Hope This Helps

[shubh]

hi, thanks for replying.

after i get my hysys pseudo components, i still do need a kinetic model for thermal cracking with these pseudo components as reactants. Is such a model available in literature? some references would be great...

From what i've read so far, I haven't found such a kinetic model involving NBP based lumps (or hysys pseudos). I have found one involving 5 lumps based on solubility : Toluene insolubles (coke), asphaltenes, resins, aromatics and saturates. (Process Chemistry of Petroleum Macromolecules, I.A. Wiehe). unfornutately i've so far not been able to find a way to convert composition based on a TBP curve to composition in terms of these lumps.
Any ideas, ever encountered such a problem?

Thanks alot

Edited by shubh, 16 June 2010 - 01:43 PM.

[Bharat Abhyankar]

Hi Shubh,
I havent came across any ready made model based on Pseudo Components. If it was then no refiner would have purchased expensive tools to model process units. Any ways, I would glance through to find out more about it.