[skbuncks]

Hi All,

I have a problem with a process that I have tried sitting in a new reactor. Basically, it does not seem able to cope with the off gassing generated in the reaction (reduction using hydrazine) without excessive foaming. Im looking for a mechanical means to rapidly dissipate the foam.

Vessel dimensions
Height: 1160mm
Diameter: 1150mm
Agitator: Off centre top entering angled (around 75º) three blade propellor (diameter of agitator head around 130mm)
Speed: 1370 rpm
Min stir volume: approx 400 L
Batch volume: 500 to 900L
Fluid characteristics
Viscosity: 0.890 to 1.0 mPas
Density: 1 to 1.58g/ml
Temperature: 20 to 40ºC

The reaction involves multiple additions each one generating 0.047 Kgmols* of nitrogen over approx over 2 min resulting in a 12inch head of foam. The foam takes a couple of hours to dissipate whereas the desired time is under 5 min.

The capital is available to replace the agitator, replace and resite the motor and add baffles to the reactor, but before doing any of these we need to be pretty sure that they will be successful.


* strictly speaking this is the amount that would be evolved if we could make a complete charge, which can't as the foan head bulids to quickly and we need to be able to see the reaction liquors to monitor for colour changes.

skb