Incinerator caustic scrubber ORP

[azav8ter]

I have a venturi scrubber followed by a Packed Tower for controlling emissions from a large incinerator. We maintain the pH of the caustic scrubbing solution to above 8, typically it is 8.5. I have been tracking the ORP of the solution as well. We have been around 100mV. I have been reading conflicting info regarding ORP values. Some info say zero and other say 600mV. We are using NaOH to scrub out acid gases from the incinerator. I believe ORP is a more valuable indicator as to the amount of caustic that is available for exchange in the packed tower.

Any help would be appreciated.
Doug

 

[kenvlach]

ORP is useful if oxidizing something (organics, ammonia) or reducing something (hexavalent Cr). It would also be useful for nitric acid (an oxidizer), but not sulfuric, hydrochloric or hydrofluoric, nor caustics.

 

[910366]

it should be controlled by conductivity. better choice