"modified" marbles: a better column filling ?

[Grayson_Stewart]

Brought over from old forum

Dirk
(Unregistered)
06/07/02 08:18 AM
"modified" marbles: a better column filling ?



Hi,

I am planning to use glass marbles (diameter 16 mm) as column (diameter 12 cm) filling, appreciating the many qualities of glass.
But I was wondering if the functioning of these glass marbles could be improved by lightly sandblasting them. Their surface would become more rough and would also increase. I am figuring that maybe this might cause an improved liquid/vapour exchange (a shorter HETP).
Since sandblasting the marbles is practically an irreversible treatment, I am posting this question before I start experimenting.

Anybody some experience on this topic ?

Thanks !



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MOONSHINER
(Unregistered)
06/13/02 09:50 PM
Re: "modified" marbles: a better column filling ? [re: Dirk]



I think sandblasting the marbles would be an acceptable practice provided you boil them in some water before using, as sometimes sandblasters are cleaned using toxic chemicals. Either that or you could just use smaller marbles. You didn't say how tall your column was.

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Dirk
(Unregistered)
06/15/02 02:44 PM
Re: "modified" marbles: a better column filling ? [re: MOONSHINER]



Thanks for the answer.

I plan to make my column between 210cm (7feet) and 300cm (10feet) high to create a reasonable amount of "stages": seven or eight.

I have really no choice for smaller marbles: those I can buy cost a little more than one US Dollar for 200 (they're imported from China) and I think that's a really good deal.

Although in my head I really appreciate the use of stainless steel scrubbers, I am a little bit afraid for their maintenance and durability in the long run. To clean and repack well a bigger size column with scrubbers will not be that simple. I'm planning to clean my marbles-filled column by just flushing it with hot water.

I would "sandblast" the marbles myself by letting them run for some time in a cement-mixer together with some sand and water. The marbles are bound to get the same surface-texture as the beautifully "sandblasted" glass we can find between the sand on the seaside.

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MOONSHINER
(stranger)
06/16/02 03:13 AM
Re: "modified" marbles: a better column filling ? [re: Dirk]



Dirk have you thought about raschig rings? they provide way more surface area than the marbles you have described. They have no effect on purity or flavour as they are glazed and are perfect for a boiler column.For more info go to

That tower is awfully tall isnt it? I know a guy here in Oz that has a column that is 1.6m tall (5-6 feet) and he gets 94% purity from a single run, so I don't see the need to go any taller than that. But its up to you. I hope this helps and good luck.

I'm not as think as you drunk I am.

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Swede
(Unregistered)
06/16/02 11:28 AM
Re: "modified" marbles: a better column filling ? [re: MOONSHINER]



It´s gonna take a awfull lot of heat to warm up such a long tower. But the result shoud be very good. (I hope).

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Anonymous
(Unregistered)
06/16/02 03:17 PM
Re: "modified" marbles: a better column filling ? [re: MOONSHINER]



Moonshiner, thanks for thinking with me.

I'm afraid that raschig rings are way too expensive if compared to the price of my marbles.
I understand that with raschig rings I would be able to obtain the same output with a smaller (length and diameter) column. But I am getting all of my stainless steel components in a junk yard, so the price of a taller column is really not high (I even found a used stainless steel barrel: 220 liter volume!).

Marbles as column filling create only one stage every 35 cm or so. In my case a 245 cm high column gives only 7 stages. Your friend in Oz probably has a better column filling. Stainless steel scrubbers give something like only 12 cm between each stage, so a column of 160 cm has already something like 13 stages, hence much easier a higher purity!

Yes, because of the marbles my tower is bound to be heavy and tall. I plan to fix it semi-permanent against a wall and pivotable in the middle (to get the marbles in and out without accidents!)

I hope to finish this project and will not hesitate to document this project with pictures and obtained results!

I also want to express appreciation for this very well done website!


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Dirk
(Unregistered)
06/16/02 03:40 PM
Re: "modified" marbles: a better column filling ? [re: Swede]



Thanks also, Swede, for thinking with me.

Yes, definitely, this set-up will require some heat-input.
I plan to use the "secondary" heat of a wood-fired bread-oven. I am still thinking about the best way to transfer the heat: it might be an open steam system (steam bubbling in the mash), or a double-walled boiler system (functioning just like a radiator in a central heating system)

The heat losses of the (insulated) column will always be used to heat up a room (drying room for clothes)

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MOONSHINER
(stranger)
06/16/02 07:55 PM
Re: "modified" marbles: a better column filling ? [re: Anonymous]



I don't know if I would even go that far. I've got a STILL SPIRITS 5L reflux still that has one marble in the relux tower. Yes you read correctly, 1 marble in the column surrounded by a water jacket that is fed off the coiled condenser. You may be wondering what kind of purity I get from it, I get 160 proof (80% abv) alcohol from the first run. and the column is only a total height of about 22cm (9 in) from the boiler dome to where the thermometer sits. You might think that this isn't a very high percentage, but it makes it easy to water down to drinking strength (ratio of 1:1). this cloumn is extremely easy to operate and produces about 1L in 45mins and takes about 25 min to heat up.Because its so small, it does not need any support and the tower can be easily removed and adapted to just about any boiler. this is heaps for me as a wash of 20% @ 25L produces 10L of 40% vodka in 8 days , which is far more than I can drink as I'm only 16. good luck with your still.

I'm not as think as you drunk I am.

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Anonymous
(Unregistered)
06/17/02 03:58 AM
Re: "modified" marbles: a better column filling ? [re: MOONSHINER]



Moonshiner, I understand your point.

I must admit though that I am a little bit perfectionistic and also: I love to experiment.

This website teaches me that a tall column is ideal for experimenting since only this way the different fractions can be separated. Mixing these fractions can then be done afterwards, according to taste. It becomes thus more possible to produce a satisfying endproduct. It's just the same philosophy as trying to make a good cup of coffee or to make delicious home-made bread.

By the way: I'm not intending to use the the output of a 200 liter wash for drinking reasons only! I'm planning to experiment with ethanol as a fuel or as a component in fuel-mixes.

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Tony
(stranger)
06/18/02 12:10 AM
Re: "modified" marbles: a better column filling ? [re: Dirk]



Just make sure that you increase the column width as well - marbles take up a fair bit more space than other forms of packing, and leave little room for the liquid & vapour to get past. They only leave about 30% of the space availiable, compared to around 90% for scrubbers. This means that you'll need to just increase the diameter quite a bit compared to "scrubber" designs.

Tony

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Swede
(Unregistered)
06/22/02 05:37 PM
Re: "modified" marbles: a better column filling ? [re: Dirk]



I had a double-walled burner before. With oil heating. Worked fine.
I´m looking forward to se the result. You obviously have some interesting idea´s.

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Dirk
(stranger)
07/06/02 03:55 PM
Re: "modified" marbles: a better column filling ? [re: Swede]



I'm still waiting for the marbles (I ordered 20.000 marbles of 16 mm diameter).

In the meantime I will do a test to find out if more liquid will adhere to sandblasted marbles than to non-sandblasted ones.