2 replies to this topic

[New Chemi]

Hi Everyone.

 

I am trying to calculate solubility of ethane, propane- propylene mix, iso-butane, n-butane and de-methanized Y-grade in brine.

 

Can anyone help me with formulas or provide any directions?

 

Thank you,

 

VJ 

[serra]

depending from operating conditions an option could be a EOS with specific mixing rules,

the selection of model should depend also from availability of specific parameters,

here I presume you have no experimental data to fit,

differently (you know solubilities) you may fit a model or

interpolate in a table of values.

Edited by serra, 04 June 2014 - 07:14 AM.

[MrShorty]

I might be revealing my own ignorance of "standard industry parlance". My first question when reading this was one of context: are you talking about 2 phase equilibrium/solubility (vapor + liquid phases) or 3 phase equilibrium/solubility (vapor + hydrocarbon liquid + aqueous liquid)? Theoretically, there is not always a lot of difference in the thermodynamic equations for vapor+liquid and liquid+liquid equilibrium, but, in practice, I tend to think about them differently. For example, if this is a "gas" solubility type problem (2 phase), then I might be looking for Henry's constants and try using Henry's law for my computations. If this is a liquid/liquid problem, I might be thinking more in terms of activity coefficients and how to solve the activity coefficient equation for mutual solubilities.

 

Quantitatively, I would tend to start with the case for pure water. It depends a lot on exactly what I am doing. For a "seat of the pants, empirical estimate", I would calculate the desired solubility in pure water, then state some kind of "correction" for the how the salt might increase/decrease the solubility and work from there. Considering how insoluble hydrocarbons are in water, even if I am in error, I am still showing that the hydrocarbon is very insoluble.