2 replies to this topic

[phoroogh]

Hello there, I have a question regarding the title. As far as I know, we determine the operating pressure of a column by considering the cooling medium temperature and the temperature approach for the condenser. But what if we don't have a condenser? 

Actually, that is my next question: When do we not consider a condenser for our column? It seems absorber columns, for example, do not usually need condenser or re-boiler. What is the reason?

I am really grateful in advance for your replies and guidance.

[fallah]

 

Actually, that is my next question: When do we not consider a condenser for our column? It seems absorber columns, for example, do not usually need condenser or re-boiler. What is the reason?
 

 

Hi,

 

In general, the best operating pressure for an absorber is the one in which the absorption column will result in highest performance in absorption operation...

[Pilesar]

In general, colder liquids at higher pressures can hold more vapor in solution. A warm carbonated soft drink does not hold its fizz as well as a cold one. Absorbers have liquid entering the top of the column. Cooling that liquid before it enters the column would be more efficient than trying to condense the vapor overhead to supply additional reflux. Using a reboiler on an absorber would just drive off the vapor you are trying to take out the bottom of the column.