hydrate formation temperature and pressure with free water option

[tmander]

I am comparing the different Hydrate Formation conditions (pressure, temperature) calculated with the options

-free water
-calculated water equilibrium
-multiphase equilibrium

it seems that for free water option results are comparable with GPSA values,
while I am not sure about water equilibrium and multiphase equilibrium options,
do these options require some additional settings ?

[matrenel]

when calculating hydrate formation temperature or pressure
if you set multiphase option in PRODE PROPERTIES,
for solid phases (as ice) the fugacities have lower values (compared with those calculated with free water option),
and the hydrate formation curve can be very different .

[tinom]

thanks asanter,
indeed they can produce different values,
one must take care to select the proper model.

[Almart]

I can confirm (based on my experience with the software) that the different options for hydrate equilibria can generate quite different values for temperature (or pressure) formation,
I select the conservative approach (multiphase).