Saturday, 28 July 2018

Sequence involved in Thermophysical properties(Fixed Properties and Temperature Dependent Properties) in Chemical Simulation Software

I have been reading some excellent literature where I tried to learn sequence of calculations involved in Thermophysical properties.

Let's start with assay processing where from TBP curve we will get Normal boiling point, composition and specific gravity as out put for each cut components.
Additional reading : Mid point average and LV% method, Watson K factor /Charecterization factor equation.  Where these methods used to convert curve to pseudo components as per cuts defined.All these methods uses boiling point and Gravity as main input.
Reference: Characterization of Petroleum fractions by Dr Qaiser Muslim Abid Ali Assady. And Characterization of Petroleum fraction Hassan S Nazi.

Now think like we have Normal Boiling Point and Gravity for each pseudo component.

Now we have to calculate Critical properties (Tc, Pc, Zc, Vc, Acentric factor)
All these fixed properties are derived from either RIAZI Dubert, Cavet 1962,Cavet 1980,TWU..  I calculated using RIAZI Dubert we got a good match however TWU is suggested because it will do some back calculations to check whether calculations are correct.

Now Temperature dependent properties at desired temperature.  Vapor Pressure (extention of Antoine equation), Acentric factor (depends on reduced  vapor pressure pitzer Correlation) .
 Density(from eos by eliminating V) Vapor pressure(extension of antoine - reidal) , Enthalpy (yan Alexander and Lee kessler,  William for solid H) .I got this understanding by reading one paper ( Thermophysical properties of UF6 which are required for stress testing when engraved in fire where literature data is not sufficient to calculate at higher Tr and Pr)

Note :
This is only for theoretical purpose only.  And there is no guarantee on using for research / any other purposes. 

2 comments:

CPP- Co generation Power Plant

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