3 replies to this topic

[kenalizer]

Hi there,

 

As you all know, there is usually a throttling valve before the feed stream enters the flash drum. 

 

Can anyone tell me how to calculate the temperature drop across the throttling valve ?

 

I can simulate the temperature drop in HYSYS but I do not know how that is calculated. 

 

For your information, my feed is in liquid state.

 

I read about the Joule Thompson effect/coefficient and is that only applicable to gases? 

 

Thank you.

[shubhang]

Hello kenalizer,

I think you can use simulate it using a flash drum, with feed pressure as valve upstream pressure. The flash drum pressure can be set to the downstream valve pressure. This should give you the temperature, vapor fraction etc.

That is one way of doing it. Other way is use an adiabatic expansion setting for a valve in Aspen and it gives you the downstream temperature.

[kenalizer]

Thanks for the reply.

 

I have no problem getting the temperature drop in HYSYS.

 

But I'm writing a report on the flash process. It would be best if I can demonstrate how HYSYS calculates the temperature drop when the pressure drops with manual calculation.

[breizh]

kenalizer,

Probably good to support your work .

 

Breizh