Dear sir,
I need to design orifice for safety valve. for that I need latent heat of vaporisation of process fluid(Hydro carbon).
For that can I use the Mass heat of vaporisation value appear on stream properties in Hysys for that particular composition(stream). please help.
During PSV sizing( Fire Case) , we know the set pressure( below the MAWP) but not relieving temperature, to find it can I fill the Pressure(set Pressure) for that particular stream & put Vapor fraction=1 in hysys then some temperature displays. Can I use that temperature as relieving temperature.

Please suggest.
Thanks & regards,
Abdu

What exactly you are looking for ?



Yes at single point but No for many points...

If liquid in vessel in equilibrium in vapor and external heat input... the relieving temperature can varies from initial boiling temperature at saturated liquid (x=0) to final boiling temperature at saturated vapor (x=1).

If only vapor (x also 1), heat input will increase internal energy...then the temperature could continue to rise...

Dear Joewong
Will you please guide us by worked out examples to understand clearly about the identification of relieving temp.
By using HYSYS how we can calculate,
please explain with example
Thanks
Stu

Perhaps the easiest way to calculate relieving rate for a vessel filled with a hydrocarbon mixture is to use the dynamic depressuring utility. Take a look at it, and see if you understand what it does and if you can make it work for you.