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## Re: Carbon Filtering questions.

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• Hi all, I have recently joined the group (first post, in fact). I don t actually have a still, but thus far have taken an academic interest in the whole
Message 1 of 6 , Mar 10, 2011
Hi all,

I have recently joined the group (first post, in fact). I don't actually have a still, but thus far have taken an academic interest in the whole subject on the basis that, as a chartered chemical engineer, the same principles are just as applicable to the other things that I do as part of my day job. And also because I hope that the UK government will one day see sense on the whole topic and get the law changed, or I'll move to somewhere a little more liberal, or hey, the end of the world will come and no one will mind me doing a bit of moonshining in the back garden.

Anyhooo, on to the topic in hand.

Bed volumes an hour (or hourly space velocity, HSV) is a way of representing the liquid flowrate independently of the size of vessel through which you are filtering. Its effectively the liquid volume flowrate (m3/hr) divided by the bed volume (m3). So for a HSV of 1 (/hr), you replace the volume of liquid in the bed with fresh liquid once per hour.

So, for a filtering velocity of 0.25, you replace a quarter of the bed volume every hour. For a one litre bed, this requires 0.25 l/hr; for a 2 litre bed, 0.5 l/hr. For the 1.7 l bed in the example, this is 0.425 l/hr, and for your 4ftx1.5" dia, this is 0.35 l/hr (give or take).

dl/hr is decilitres per hour. A decilitre is one tenth of a litre, hence 0.425 l/hr = 4.25 dl/hr = 425 ml/hr. Simples.

Not sure about running 96% over 50%, but it is possible that you'll preferentially absorb some water - I believe that this is one of the ways of making 100% pure spirit. I would also think that at 96%, your impurities will also be present in a higher concentration, which should improve both the rate and total amount of removal from the ethanol. Basically, I think that running at 96% will give you a purer spirit. Anyone with practical experience want to chime in?

Stay safe,
EJB

--- In Distillers@yahoogroups.com, "thewilly789" <789willy@...> wrote:
>
> I have made a 4ft by 1.5" copper filter tube filled with activated
> carbon,just to try out filtering.Have a large 2 gallon stnls stl. pot
> connected to the top to make it hold a good volumn.i have a valve at the bottom to control rate of filtration.
>
> !st question ,i have read that they use around a 50% alcohol mix,
> can i use a higher mix like my 96% that i get from my pure alcohol
> run ,does this work or do i need to dilute it down ?
>
> Also i have no idea of the rate that is talked about in "Activated carbon for purification of alcohol" by Gert Strand file i found.
>
> Quote "Bed volume per hour (HSV) is usually around 0.25 (very, very slow) when purifying alcohol, while water is usually purified at 2-3 HSV. For a pipe holding 1.7 liters, the maximum purification occurs at 4 dl per hour if the pipe is approx. 40 mm wide and the carbon grain 0.4-1.4 mm in size."
>
> Could someone put this into terms i can understand like liter's per hour.No idea what dl stands for in the above quote
>
> Thank you.
>
• Hello, Bernie the cowmical engineer. Carbon filtering has been proven to remove more impurities if diluted with water over using high proof spirits. The
Message 2 of 6 , Mar 10, 2011
Hello, Bernie the "cowmical" engineer. Carbon filtering has been proven to remove more impurities if diluted with water over using high proof spirits. The polar nature water does not lend itself to being adsorbed or absorbed easily. ps I'm a Chemical E. too.

--- In Distillers@yahoogroups.com, "berniethecow" <jon.noble@...> wrote:
>
> Hi all,
>
> I have recently joined the group (first post, in fact). I don't actually have a still, but thus far have taken an academic interest in the whole subject on the basis that, as a chartered chemical engineer, the same principles are just as applicable to the other things that I do as part of my day job. And also because I hope that the UK government will one day see sense on the whole topic and get the law changed, or I'll move to somewhere a little more liberal, or hey, the end of the world will come and no one will mind me doing a bit of moonshining in the back garden.
>
> Anyhooo, on to the topic in hand.
>
> Bed volumes an hour (or hourly space velocity, HSV) is a way of representing the liquid flowrate independently of the size of vessel through which you are filtering. Its effectively the liquid volume flowrate (m3/hr) divided by the bed volume (m3). So for a HSV of 1 (/hr), you replace the volume of liquid in the bed with fresh liquid once per hour.
>
> So, for a filtering velocity of 0.25, you replace a quarter of the bed volume every hour. For a one litre bed, this requires 0.25 l/hr; for a 2 litre bed, 0.5 l/hr. For the 1.7 l bed in the example, this is 0.425 l/hr, and for your 4ftx1.5" dia, this is 0.35 l/hr (give or take).
>
> dl/hr is decilitres per hour. A decilitre is one tenth of a litre, hence 0.425 l/hr = 4.25 dl/hr = 425 ml/hr. Simples.
>
> Not sure about running 96% over 50%, but it is possible that you'll preferentially absorb some water - I believe that this is one of the ways of making 100% pure spirit. I would also think that at 96%, your impurities will also be present in a higher concentration, which should improve both the rate and total amount of removal from the ethanol. Basically, I think that running at 96% will give you a purer spirit. Anyone with practical experience want to chime in?
>
> Stay safe,
> EJB
>
>
>
>
> --- In Distillers@yahoogroups.com, "thewilly789" <789willy@> wrote:
> >
> > I have made a 4ft by 1.5" copper filter tube filled with activated
> > carbon,just to try out filtering.Have a large 2 gallon stnls stl. pot
> > connected to the top to make it hold a good volumn.i have a valve at the bottom to control rate of filtration.
> >
> > !st question ,i have read that they use around a 50% alcohol mix,
> > can i use a higher mix like my 96% that i get from my pure alcohol
> > run ,does this work or do i need to dilute it down ?
> >
> > Also i have no idea of the rate that is talked about in "Activated carbon for purification of alcohol" by Gert Strand file i found.
> >
> > Quote "Bed volume per hour (HSV) is usually around 0.25 (very, very slow) when purifying alcohol, while water is usually purified at 2-3 HSV. For a pipe holding 1.7 liters, the maximum purification occurs at 4 dl per hour if the pipe is approx. 40 mm wide and the carbon grain 0.4-1.4 mm in size."
> >
> > Could someone put this into terms i can understand like liter's per hour.No idea what dl stands for in the above quote
> >
> > Thank you.
> >
>
• Quite apart from the technical answers already posted, you may find that things will get a little -hot- if filtering at 96%abv. Told to me by a friend who
Message 3 of 6 , Mar 10, 2011
Quite apart from the technical answers already posted, you may find that things will get a little -hot- if filtering at 96%abv. Told to me by a friend who experienced this phenomena.

dl stands for deci litre or one tenth of a litre.

I use two filtering processes. The first process is not used a lot now as I find the 2nd process to be simpler.

1. 1.5" (32mm) x 4' (1.2m) pvc pipe. 3 litre juice bottle with bottom cut out, turned upside down and fixed to top of filter column.

When first set up, after filling with AC, I blocked off the outlet hole and filled the column with water until it just showed in the juice bottle. I then drained that water into a jug to measure the volume of liquid held by the column.

Now every time I use this filter, I first "wet" it with that volume of water, and place the jug under the outlet before the water starts to flow out. When the water has almost emptied from the juice bottle atop the column, I fill the juice bottle with 50%abv product.

When the jug has collected the "wetting" water volume, I replace it with the product collection jug.

When the last of the product is about to disappear from the juice bottle, I add back the wetting water, remove the product jug and replace with the wetting water jug just as the wetting water disappears from the juice bottle. You have now "chased" almost all the product out of the column. Re-use the wetting water for a later filtering as it will have a slight product taste, or just chuck it.

2. Using 12 ltr stainless steel vessels - ex fire extinguishers - I add three of cups of AC then fill with 50%abv product. Every couple of days or once a week I swirl the vessels.

When I'm ready to use the product, I strain it into a jug, cut it to 40%abv and bottle it. The AC gets renewed after about 4 or 5 uses.

--------------------------

--- In Distillers@yahoogroups.com, "thewilly789" <789willy@...> wrote:
>
> I have made a 4ft by 1.5" copper filter tube filled with activated
> carbon,just to try out filtering.Have a large 2 gallon stnls stl. pot
> connected to the top to make it hold a good volumn.i have a valve at the bottom to control rate of filtration.
>
> !st question ,i have read that they use around a 50% alcohol mix,
> can i use a higher mix like my 96% that i get from my pure alcohol
> run ,does this work or do i need to dilute it down ?
>
> Also i have no idea of the rate that is talked about in "Activated carbon for purification of alcohol" by Gert Strand file i found.
>
> Quote "Bed volume per hour (HSV) is usually around 0.25 (very, very slow) when purifying alcohol, while water is usually purified at 2-3 HSV. For a pipe holding 1.7 liters, the maximum purification occurs at 4 dl per hour if the pipe is approx. 40 mm wide and the carbon grain 0.4-1.4 mm in size."
>
> Could someone put this into terms i can understand like liter's per hour.No idea what dl stands for in the above quote
>
> Thank you.
>
• Try looking at the coversion charts availible online. I belive dl is deciiter. That is ten liters. I have fooled around with a few activated carbon setups. I
Message 4 of 6 , Mar 10, 2011
Try looking at the coversion charts availible online. I belive "dl" is deciiter. That is ten liters.

I have fooled around with a few activated carbon setups. I found that the tube filled with activated carbon from coconut hulls, at the size of 1-3mm particles, did work very good to get a clean flavor profile. What I did not like about the method described in the Gret Strand article was all of the time and water needed. Also, I learned the first time that it was a mistake to cut with water to the % I drink befor I filterd. The water in the carbon mixed in also, giving me a very weak drink. I decided to run it again thrugh my potstill. No filtration was needed after that.
Having water in the mix does help it filter better. The longer the carbon contacts the liquid the better.

The method I prefer now is to keep my carbon in a glass contaner with an airtight lid. I do not wash it after every use. Keeping my carboy half full of carbon, prewetted at the strength I like (50%) allows me to pour in 50/50 and know I wil get the same back out. I simply pour a diluted final disttillation in the carboy and let it sit for at least 24 hours. I like to give it a swirl every now and again to let the carbon make contact with all the liquid.
Two things you should know about this method are: A drain-valve near the bottom would be nice. I have no way to drain out the liquid with out turning my carboy over. Not only is it a cumbersome task, it also allows the fine carbon particles wich had settled to the bottom, to come out into my reciving vessel. Then I have to use my 3 foot long piece of 3'' stainless steel pipe (with a funnel welded to one side) to filter out the carbon. First I push a bit of cotton down the funnel with a wood rod untill I get the reduction I want. The reduction is for reducing the particle size allowed to pass through the cotton, trying to keep the flow rate as fast as possable. The first litter or so allways has a small amount of charcoal in it so I just pour it back in the filter again. The second thing about this method is obvious. After a few runs the activated carbon becomes less than 100% effective. But, even befor I was able to make nearly pure spirit with my still alone, I was able to recive the rewards of praise from my friends after several less than perfect runs all went through the same carbon filtration process, with out being washed every time. My five gallon carboy is half full of carbon. Now that I only put nearly pure 50/50 spirit in to it, the only time I wash the carbon is if it needs it. Five runs is easily as good as the first. The longer I let sit though, the better. Just as age always makes a spirit better.
When I do need to wash the cabon, I boil it in my still for the first wash. I get to keep the distillate for starting my barbicue and washing greasy car parts. Then it is rinsed and boiled and rinsed and bioled a third time. I then drain it well and slowly heat it in the same pan as befor stiring it a bunch to let the vappor off faster. It takes a long time. Once, I spread it out on a bed sheet then laid it in the sun. While it dried fairly quick, I was not happy to see what the wind had brought for me. I have thought about just puting a second sheet on top of it but have never dried it in the sun again.

--- In Distillers@yahoogroups.com, "thewilly789" <789willy@...> wrote:
>
> I have made a 4ft by 1.5" copper filter tube filled with activated
> carbon,just to try out filtering.Have a large 2 gallon stnls stl. pot
> connected to the top to make it hold a good volumn.i have a valve at the bottom to control rate of filtration.
>
> !st question ,i have read that they use around a 50% alcohol mix,
> can i use a higher mix like my 96% that i get from my pure alcohol
> run ,does this work or do i need to dilute it down ?
>
> Also i have no idea of the rate that is talked about in "Activated carbon for purification of alcohol" by Gert Strand file i found.
>
> Quote "Bed volume per hour (HSV) is usually around 0.25 (very, very slow) when purifying alcohol, while water is usually purified at 2-3 HSV. For a pipe holding 1.7 liters, the maximum purification occurs at 4 dl per hour if the pipe is approx. 40 mm wide and the carbon grain 0.4-1.4 mm in size."
>
> Could someone put this into terms i can understand like liter's per hour.No idea what dl stands for in the above quote
>
> Thank you.
>
• Hi Timothy, dl (lower case d lower case l stands for 1 tenth of a litre, or if you prefer, 100ml (mili litres). In this case, case is everything! Cheers.
Message 5 of 6 , Mar 11, 2011
Hi Timothy,

dl (lower case d lower case l stands for 1 tenth of a litre, or if you prefer, 100ml (mili litres).

In this case, case is everything!

Cheers.

------------------------------------------------------------

--- In Distillers@yahoogroups.com, "Timothy" <timothyc.smith@...> wrote:
>
>
> Try looking at the coversion charts availible online. I belive "dl" is deciiter. That is ten liters.
>
> I have fooled around with a few activated carbon setups. I found that the tube filled with activated carbon from coconut hulls, at the size of 1-3mm particles, did work very good to get a clean flavor profile. What I did not like about the method described in the Gret Strand article was all of the time and water needed. Also, I learned the first time that it was a mistake to cut with water to the % I drink befor I filterd. The water in the carbon mixed in also, giving me a very weak drink. I decided to run it again thrugh my potstill. No filtration was needed after that.
> Having water in the mix does help it filter better. The longer the carbon contacts the liquid the better.
>
> The method I prefer now is to keep my carbon in a glass contaner with an airtight lid. I do not wash it after every use. Keeping my carboy half full of carbon, prewetted at the strength I like (50%) allows me to pour in 50/50 and know I wil get the same back out. I simply pour a diluted final disttillation in the carboy and let it sit for at least 24 hours. I like to give it a swirl every now and again to let the carbon make contact with all the liquid.
> Two things you should know about this method are: A drain-valve near the bottom would be nice. I have no way to drain out the liquid with out turning my carboy over. Not only is it a cumbersome task, it also allows the fine carbon particles wich had settled to the bottom, to come out into my reciving vessel. Then I have to use my 3 foot long piece of 3'' stainless steel pipe (with a funnel welded to one side) to filter out the carbon. First I push a bit of cotton down the funnel with a wood rod untill I get the reduction I want. The reduction is for reducing the particle size allowed to pass through the cotton, trying to keep the flow rate as fast as possable. The first litter or so allways has a small amount of charcoal in it so I just pour it back in the filter again. The second thing about this method is obvious. After a few runs the activated carbon becomes less than 100% effective. But, even befor I was able to make nearly pure spirit with my still alone, I was able to recive the rewards of praise from my friends after several less than perfect runs all went through the same carbon filtration process, with out being washed every time. My five gallon carboy is half full of carbon. Now that I only put nearly pure 50/50 spirit in to it, the only time I wash the carbon is if it needs it. Five runs is easily as good as the first. The longer I let sit though, the better. Just as age always makes a spirit better.
> When I do need to wash the cabon, I boil it in my still for the first wash. I get to keep the distillate for starting my barbicue and washing greasy car parts. Then it is rinsed and boiled and rinsed and bioled a third time. I then drain it well and slowly heat it in the same pan as befor stiring it a bunch to let the vappor off faster. It takes a long time. Once, I spread it out on a bed sheet then laid it in the sun. While it dried fairly quick, I was not happy to see what the wind had brought for me. I have thought about just puting a second sheet on top of it but have never dried it in the sun again.
>
> --- In Distillers@yahoogroups.com, "thewilly789" <789willy@> wrote:
> >
> > I have made a 4ft by 1.5" copper filter tube filled with activated
> > carbon,just to try out filtering.Have a large 2 gallon stnls stl. pot
> > connected to the top to make it hold a good volumn.i have a valve at the bottom to control rate of filtration.
> >
> > !st question ,i have read that they use around a 50% alcohol mix,
> > can i use a higher mix like my 96% that i get from my pure alcohol
> > run ,does this work or do i need to dilute it down ?
> >
> > Also i have no idea of the rate that is talked about in "Activated carbon for purification of alcohol" by Gert Strand file i found.
> >
> > Quote "Bed volume per hour (HSV) is usually around 0.25 (very, very slow) when purifying alcohol, while water is usually purified at 2-3 HSV. For a pipe holding 1.7 liters, the maximum purification occurs at 4 dl per hour if the pipe is approx. 40 mm wide and the carbon grain 0.4-1.4 mm in size."
> >
> > Could someone put this into terms i can understand like liter's per hour.No idea what dl stands for in the above quote
> >
> > Thank you.
> >
>
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