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[zikri]

Hello,

I have a question regarding partial pressure,i think this is a very simple question.

In a distillation column there are side cut stripper but certain side cut have a reboiler and some use stripping steam .

my question is :

What effect partial pressure of liquid ?
why kero used reboiler rather than stripping steam ?
Why diesel have dryer ?
Why diesel side cut do not used reboiler ?

Thank you

[S.AHMAD]

Zikri
1. What effect partial pressure of liquid ?
Liquid does not create vapor pressure only gas/vapor exerts partial pressure by Dalton'sLaw and partial pressure related to vapor pressure by Roult's Law. Vapor pressure is a function of temperature and partial pressure affected by presence of inerts (e.g. steam)

2. why kero used reboiler rather than stripping steam ?
Some old design of side stripper using steam stripping instead of reboioiler. However, reboiler is preferrable due to problem associated with high water content such is formation of ice which is undesireable for jet kero. Using of reboiler is also associated with efficient heat integration. If steam stripping is beig used, the facilities require extensive water removal system (e.g dryer/coalescer).

3. Why diesel have dryer ?
Dryer removes water. Water at tank bottom promotes biolological growth. This may eventally carried over to dispenser and eventually clogging diesel filter.

4. Why diesel side cut do not used reboiler ?
If you have the source of energy why not? normally sue of reboiler is assocoated with effecient heat integration in a comples refinery. I have seen refinery using furnace as diesel reboiler. Normally for diesel, using stripping steam is the most energy efficient operations since the diesel bottom temperature is lower due to the effect of inerts (steam). Reboiler requires higher temperature that may result in thermal cracking of diesel.

Hope the above answers you questions.