2 replies to this topic

[darknight1991]

Hi all,

I’m working with a characterized crude assay using assay manager in Aspen HYSYS and had a question on adding a pure component to it.

Specifically, I would like to add Toluene (need to monitor it) as a separate component to the crude assay. However, I understand that in a characterized crude, components are typically represented as hypo-components based on boiling point ranges rather than individual pure components.

Could someone please advise on how to add a pure component for my case?

[Pilesar]

Characterization using boiling point pseudo components can be for just a part of the whole stream. If you have pure component analysis also, you can add them in as "light ends" and cut off the pseudo components at a specific boiling point. From your question, I suspect you do not have any pure components known except for toluene. If that is the case, then characterize the assay according to cutpoints first, then consider mixing a stream of the right amount of Toluene and subtracting the same amount of the similar boiling point pseudo component. Depending on what you are modeling, a full composition of light ends may be needed to get a good simulation.

[SilverShaded]

As far as thermodynamics goes real and hypos work in exactly the same way, all depend on TC, PC, Omega etc.  So you can simply add toluene into any hypo-component stream, provided you maintain mass balance.  However, be carefull if playing with the assay amanger as it kind of sucks handling real components.  The other way to do is to assign a toluene percentage to the appropriate hypos-component, less accurate in terms of boiling point.

A third option is to replace the entire naphtha portion with PONA data.  Technically more correct.