Request suggestions for thermal degradation calculations

[hollerg]

I need to control degradation when I renovate an existing evaporator to run at a lower pressure, but at a higher level of moisture removal from an organic acid. The equipment has an external exchanger, with a 100 to one circulation to product discharge rate and a 50 to one inventory to product discharge rate. Temperature rise is only a few degrees each pass. Back-pressure suppresses boiling in the tubes to prevent salts from fouling the surface.

For degradation that doubles for every 10 C rise in T, is there a relationship to apportion the relative contribution of the damage the heat exchanger surface temperature causes and the degradation in the bulk @ the flash temperature?

Your suggestions on how to deal with the heat exchanger contribution in the recycle loop, would help a great deal

I hope to perform preliminary engineering of surface area, heat transfer enhancement or volume reduction while waiting on the kinetics to be measured.

Thanks for suggestions.
Gary

 

[hollerg]

I am considering setting up the reaction model to be two parts: 1) A mixed-flow reactor (CSTR) to account for the reaction at bulk T. 2) A second mixed-flow reactor at the temperature of the wall and limiting the volume of the second reactor to the thickness of 1/64th of an inch to represent the reaction. Only @ ~ 6000 Re#, 14 cP fluid.

Comments?