Acetic acid recovery-boil-out-condense?

[krecian]

I have to design a kettle reboiler for boiling-off 28% acetic acid which contains some salts and no other liquids. Rate: 250 kg/h. Monstinski pool boiling equation gives absurdly high area requirements. Help!!? (I have no simulators or Sw. Only spreadsheets)
The condenser has cooling water in 35 and out 40 deg c. Vertical or horizontal? Any suggestions for the system?

(other methods such as liq-liq extraction are not considered. This shd be a no-cost/minimum cost set-up. But not a Heath-Robinson)

KRECian

 

[25362]

Othmer says "dimerization" accounts for many of the apparent anomalies in AcAc's equation of state, transport properties, thermodynamic functions, etc. At the atmospheric BP (118^oC) AcAc dehydrates to give traces of Ac anhydride.

As far as I am aware of, at present there is no simple, general equation available for calculating the HTC for pool (nucleate) boiling.

For "organics" boiling with steam, the literature gives overall U values with a range of 0.7-0.8 kW/(m²K), fouling and burnout heat flux excluded. You may use this value for comparison.

 

[krecian]

Thanks 25362,

My calculations give me 1.2 W/m2.K. Close to the values given by you.
But, boil-out is not a problem for me. Based on rough-cut design and actual fabrication and use, have told us that calculations are more than adequate. Condensation design often seems to be inadequate. I tried two designs for the same capacity and both are not giving reqd qtty of condensation. (I have used vertical condensers, Basic Nusselt theory).

Any more suggestions? Anybody?

KRECian

 

[25362]

For condensers using cooling tower water (forced convection) the same sources give a wider spread: 0.5-0.9 kW/(m²K).

 

[krecian]

25362,

Thanks. My calcs are giving me 0.47 kW/m2.K. Specs are all ready for system fabrication and then erection. Let us see how close we are.

KRECian