Input for Hysys

Dear Friends,

Recently our partner made an audit and said that “Oil and gas stream must be at equilibrium at separator outlet in an HYSYS simulation because in a separator oil and gas are at thermodynamic equilibrium” so could you advise whether we have any rule mention that “the input for hysys must be at equilibrium”

(The actual boiling point pressure is different with the BP in hysys model).

Thanks in advance.
MLee

The outlet streams from a separator in HYSYS will be at equilibrium by definition. There is no rule to say that the inlets to the separator must be at equilibrium. For example, you can have streams at different temperatures and pressure which will equilibrate within the separator.

Thanks Gtaa,

Our pipeline length 18km, gas oil volume fraction is 0.01, Pipeline fluids temperature to 23deg. and rising to operating temperature 28deg.C (surface temp absorption- at Seperator) but below wax appearance temperature and pour point 30deg.C -33deg.C if the waxing of oil into large crystal/lumps can affect the dynamics of equilibrium and cause the waxy oil deposits to under absorb the equilibrium gas to remain under saturated.

Thanks in advance.
MLee

Thanks Gtaa,

Our pipeline length 18km, gas oil volume fraction is 0.01, Pipeline fluids temperature to 23deg. and rising to operating temperature 28deg.C (surface temp absorption- at Seperator) but below wax appearance temperature and pour point 30deg.C -33deg.C if the waxing of oil into large crystal/lumps can affect the dynamics of equilibrium and cause the waxy oil deposits to under absorb the equilibrium gas to remain under saturated.

Thanks in advance.
MLee

I'm afraid I don't understand the question?