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Simple Batch Distillation. Bottom And Top Temperature


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#1 bmicky

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Posted 18 September 2019 - 01:58 AM

Hello,

I try to model the separation of n-pentane from the syntetic seal oil/n-pentane miscible mixture by a simple batch distillation process (reboiler + riser+condenser) at the atmosheric pressure. The n-pentane boiling temperature is 38 deg.C. and oil boiling temperature is about 270 deg.C. According to the oil/n-pentane VLE data (which were created based on the Raoult's law),for example at the reboiler's temperature of 60 deg.C, the equilibrium n-pentane (Y) concentration in vapor is 0.9998 and oil is 0.0002.

Is it correct to assume that at the simple batch distillation process, the vapor (top) dew point temperature, assuming when n-pentane (Y) 0.9998 is similar to the botomm bubble temperature of 60 deg.C ?

On the other hand,once the vapor phase enriched with low boiling n-pentane, I would expect to see the vapor temperature closely to 38 deg.C. Is there a temperatute difference between a reboiler and condenser for a simple batch distllation process ?

 

 

Thanks, Mike



#2 breizh

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Posted 18 September 2019 - 06:29 PM

hi ,

What you describe is a boil off system or one stage distillation equilibrium . You can model it like a flash .

At the top you should recover the light component at its corresponding temperature and pressure.

 

note :

No other light component in the mixture to explain the temperature ?

What about head loss in the system ?

 

Good luck

Breizh


Edited by breizh, 18 September 2019 - 06:43 PM.


#3 bmicky

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Posted 19 September 2019 - 01:21 AM

Hi Breeizh, Thank you.

Yes. It's one stage distillation equilibrium.

Can I assume that at the reboiler's temperature of 60 deg.C, when the equilibrium n-pentane (Y) concentration in vapor is 0.9998 the vapor temperature (dew point) is 60 deg.C  or closely to 38 deg.C(assuming heat losses are negligible) ?

 

Thank you. Milke 



#4 breizh

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Posted 19 September 2019 - 11:05 PM

Hi ,

Is there a chance to confirm the quality and temperature of your product (top)  in a lab ( simple distillation ) ? 

The pressure corresponding to a boiling temperature of 60 C is about 2.15 bar !

Do you have packing inside the riser or is it just an empty pipe? 

 

A document to support is attached . 

 

Good luck

Breizh 

Attached Files


Edited by breizh, 20 September 2019 - 02:35 AM.





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