[curiouscat]

If one were to design a wet scrubber for acetaldehyde fumes is water a good (practical) choice or would there be a better agent? e.g. caustic, some solvent etc.

[discodermolide]

Acetaldehyde is quite volatile, I don't remember the V.P.
I would use a bleach scrubber and oxidise it. I assume you have efficient cooling, -30°C on the condenser then a lot of vapour should not go up the tube.

[curiouscat]

Acetaldehyde is quite volatile, I don't remember the V.P.
I would use a bleach scrubber and oxidise it. I assume you have efficient cooling, -30°C on the condenser then a lot of vapour should not go up the tube.

Thanks for the bleach idea!

Yes, VP is high. We do have a chiller line  on the condenser though, not quite -30 C. Under normal ops things seem to work fine. This scrubber will come into play only for residual fumes during upsets.

[curiouscat]

What's a good way of calculating how cold a condensor one needs for an application? 

The OSHA PEL is 200 ppm. Is that a good basis? 200 ppm, if I calculated correctly, comes to a mole fraction of 2×10^-4

That'd mean going down to a temp. where Vap Pr of Acetaldehyde was 1mmHg. This doesn't seem right to me.

Can one take credit for the fact that no one's literally sniffing at the condensor? Some sort of distance abatement?

Or do I have a calculation error.