# Scrubber Internals



## Tub Buster (Feb 1, 2014)

Here are a few ideas for the do-it-yourselfers...

Scrubber Tower Packing

4metals mentioned a lab bench sized scrubber consisting of two 4 liter flasks filled with marbles. 8 liters of marbles will cost about $200! Perhaps quartz pebbles would be an alternative.

For full-sized scrubbers, let's do the math. Say you want to fill it with Bio Balls. They cost about $100 for 15 gallons of balls. 

If your tower is 12" in diameter and you want to fill 5 feet with bio balls, the volume is pi times the diameter squared divided by 4 (same as radius**2), times the length. So pi (3.14) times 1 foot times 1 divided by 4, times 5 =
pi * 5/4 = 3.93 cu ft or 29.4 gallons. Call it 30 gallons, so it will cost $200.

If the tower is 2 feet in diameter, the volume is pi * (2 * 2 / 4) * 5, or 5* pi, which is 15.7 cu ft = 117.5 gallons. Divide by 15 and we get 7.83, so it will cost $783 for just 5 feet.

Plastic snow fence has been mentioned before as an alternative to expensive random packing. It sells for about $20 for 50 feet x 4 feet at Home Depot. I'd suggest using that, and then filling the voids with about $50 of bio balls. (Continued next message).


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## Tub Buster (Feb 1, 2014)

Packing bed support

Raschig.com and machengineering.com sell support trays for holding the tower packing. It can get heavy, so something strong but corrosion-resistant is required. Below are photos of the commercial packing supports, and below that some commonly available substitutes. 

The first is for large diameter towers. It is the tray used by bakeries for delivering bread. Just ask a bakery if they have old trays they'd like to sell cheap.

For 12" towers, you can use the plastic crates used to deliver milk. Just cut to size. GSP mentioned he's used one as an anode tray in a small Thum cell, so they have multiple uses.


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## 4metals (Feb 1, 2014)

Out with the marbles, in with bio balls. This handled all of the fumes in a 4 liter sealed reactor digesting 1/2 kilo lots of karat scrap.


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## Tub Buster (Feb 4, 2014)

4metals said:


> Out with the marbles, in with bio balls. This handled all of the fumes in a 4 liter sealed reactor digesting 1/2 kilo lots of karat scrap.


I like it! Good way to get started without a big investment. Problem is, those 4 L. Erlenmeyer flasks cost around $100 each. Would you know of a source with better prices?

The snow fence is a bit flimsy, even if one purchases the stronger security fencing, so I was thinking of making a sort of "jelly roll" with some sort of low density plastic wool. 3M company is known for making Scotch Brite cleaning pads, but they also manufacture miner's moss. I would not be surprised if they have a material that can be used in a scrubber, without increasing resistance for the blower too much. I'll have to look into this.


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## Tub Buster (Feb 5, 2014)

I found these artificial "grass balls" in a dollar store. They are near-perfect for packing material, but cost $2/each if bought retail. However, the supplier in China charges from 5 cents to 15 cents each, depending on size: 12cm, 15cm, 18cm, 23cm, 27cm, 35cm, 45cm, and 52cm diameter.

More info here: http://ruopei.en.alibaba.com


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