The authoritative public forum
  for Metal Finishing since 1989
  

  -----

How to fabricate a fume scrubber?

2004

I have been doing some research into fume scrubbers as I require a small scrubber for my lab scale type II anodizing line which is to be put into construction in the near future. Of course I do not expect companies to come forth with their detailed schematics for their equipment, however, I am searching for information regarding a fume scrubbers design.

I intend on constructing my own small unit, in part for educational purposes and in part for economical reasons. My questions are as follows :

1. Has anyone here successfully fabricated a functioning fume scrubber (of any scale) and if so, what information can you pass on to me?

2. Is anyone familiar with a source of information regarding the design and fundamentals of fume scrubbers?

3. Does anyone care to pass along any advice, information and/or concerns?

Thanks to all who participate. I realize that the task at hand may indeed be a difficult one, however, I am confident that with your help I will succeed. Though I don't feel this is the time to ask this question yet, just so you are aware, if the time should come I will be interested in finding a person or place where my scrubber can be performance tested. Thanks again...

Daniel DeGueldre
anodizing shop entrepreneur - Ste. Anne, Manitoba, Canada

---

2004

Golly Moses, Daniel, you sure don't want much, do you?

There are, for your purposes, two types of scrubbers.

The 'old' type (which will infuriate some people) is called mass transfer. What you do is to have a 'cylinder' and fill it full of packing and then spray the appropriate neutralizing liquor onto that.

But this generates a cloud of very wet particles and you need to remove them. How? Often by using some mesh...,.but this design is for vertical usage only ... and the design factor is normally max 400 fpm.

Packing? There are many sources. Was it Tribar? I forget ... and if you speak to one of the engineers, he will ask you a) what is the chemistry b) what efficiency do you want to remove it at ... and then tell you to use size 'XYZ' packing, 'X' feet high (or tall) and spray it with 'Y' gpm. This also means you need a tank, pump, float valve.

There is another method ... using sine curved mist eliminator blades. But again one needs to KNOW just what you want to scrub! For chrome, ah, you can achieve 0.8 Mg/M3 if you have the right set-up (which was A.OK in the 80's in B.C.) but isn't good enough for EPA specs.

Then you can reduce the micron size from 10-12 down to LESS than 3 microns using a so-called coalescer design ... I've done it (Ontario) for Bright Dip. See the archives # 4396, 6733 and 14944.

Many, sorry, MOST plating emissions are NEITHER fumes nor gases, irrespective of what the text books will say, they consist of mainly invisible low micron droplets.

It takes YEARS of experience to come up with a reasonably good scrubber design, so don't imagine that you can willy-nilly make one at home overnight. Sorry, but it can't be done.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

---

2004

Daniel,

My scrubber is primarily for particulates so this may not apply to your situation. Scrubber is pvc sch 80 (sch 40 ok but 80 is heavier), motor w/fan, fine mist spray head, lots and lots of perforated little plastic balls (for more surface area), water and drain. Suck gas up through ball. Spray water down on top of balls. Drain water and whatever it scrubs out to appropriate treatment tank for proper disposal.

That said, be careful! There are a lot of companies out there putting time, research and money into making efficient scrubbers. They have already made the mistakes and corrected them. Might be better off to price out a cheap shelf model and purchase it.

Good Luck

Trent Kaufman
electroplater - Galva, Illinois