CO2 pressure

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Pikey
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CO2 pressure

Post by Pikey »

Ok so we generate a real load of CO2 in our ferments.

I want to collect this CO2 and pressurise it, so I can use the pressure later to move wash from the ferment vessel into the still. All I need is a on/off tap on the top of the boiler and a sight tube, to assess the level reached.

I don't need a huge pressure - 2 -3 bar would do the job easy. - Maybe even 1.5 Bar ?

Has anyone devised a method of using the ferment gas - to push wash from the fermentvessel into the cooker ?

OR to collect the ferment CO2 in a condensed form in order later to use it to do work ?

I do feel we are missing a lot of opportunity here. :?
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Re: CO2 pressure

Post by NZChris »

We are distilling, not making beer, so it's not important.

Making beer, most plastics let CO2 through fairly quickly, but if you don't leave your ferment dead for too long, you may still have enough left. Mylar is better.
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Re: CO2 pressure

Post by Kareltje »

If you do not make beer or champagne, but are only interested in the moving capacity, why not use simple pressurized air?

And use the CO2 in a greenhouse for stimulating plant growth? Grain or fruit, for example?
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Re: CO2 pressure

Post by cob »

Pikey wrote:Ok so we generate a real load of CO2 in our ferments.

I want to collect this CO2 and pressurise it.

I do feel we are missing a lot of opportunity here. :?
an oilless air compressor will compress co2. it will also compress air, meaning you don't need the co2,

just the compressor.

are you related to Rube Goldberg?
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Re: CO2 pressure

Post by Pikey »

Yeah I thought about using air and have a decent compressor. Point is that by using CO2, I have a blanket over the must that it's used to and is fairly sterile. If I use air, I'm pumping in all sorts of fungal spores and bacteria which are potential spoilage organisms and introducing oxygen for them to use.

My big fermenter is 220 Litres and my little unit is only 25 Litres, so I can'y deal with that all in one go.

At 4 hours a time, I can get 3 - 4 runs in a day, whereas if I wait for it to all cool down, take off the lid and bucket the wash over, I can get 1 run a day and spillage / drips which have the potential to make the area unhygienic.

If I just tap off the backsett and pump over a new fill, no spillage and I'm back in production, without having to clean anything down, or split any joins.

I have a 25 Litre Rotokeg which is used for pressurised beer and I'm thinking if I can get that maybe 1 bar pressurised or even 1/2, I can hold enough pressure to lift pretty much all that over.
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Re: CO2 pressure

Post by Pikey »

Actually I'm wrong - Boyles law states what P1V1 = P2V2 (constant Temp) - so 1 bar would only just replace 25 Litres and I'd need more than that to lift the last of the wash over. :(

So I'd need something like 5 Bar for a day's work. - I don't fancy putting 70 psi in plastic, so it looks like we're back to the submersible bilge pump and gumming up the works from time to time.
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Re: CO2 pressure

Post by NZChris »

1 Bar will lift water 400". How high do you need to pump it?
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Re: CO2 pressure

Post by Badmotivator »

If your premise is sound (co2 is useful to move ferment to boiler, keeping fermenter sanitary) then you might consider just buying a tank of co2. It'll probably be less trouble and expense than compressing it and storing it using a homemade system. Hope that helps.
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Re: CO2 pressure

Post by Pikey »

NZChris wrote:1 Bar will lift water 400". How high do you need to pump it?
My thoughts exactly Chris. - I only need to lift it a maximum of 48" depending on how empty the fermenter is.

However, what I forgot at that stage was that If I have 1 bar (1 Atmosphere - about 14.7 lb/sq inch) overpressure and I let it pressurise my fermenter, it will lift the wash yes, but the displaced wash will be replaced by CO2 from my pressure vessel, until the pressures equalise, or I shut the valve down. Now 25 Litres CO2 will replace 25 litres of wash, but the pressure will drop as my original 25 litres at 1 bar, is now occupying 50 Litres of space ! so looking at Boyles law we have 25 litres at 2 bar (1 atmosphere to get "neutral" plus 1 atmoshpere of "overpressure") x 25 litres = 50 litres at 1 atmosphere (neutral) - hence I lose all the lifting capacity because the gas now takes up twice the space !

Thus to lift 4 x 25 litres, I need a little over 4 atmospheres of overpressure - ie something over 60 psi.
Badmotivator wrote:If your premise is sound (co2 is useful to move ferment to boiler, keeping fermenter sanitary) then you might consider just buying a tank of co2. It'll probably be less trouble and expense than compressing it and storing it using a homemade system. Hope that helps.
True BM and I used to "gas" up my homebrew with an old sodastream, by stamping on the machine and using the works and cylinder to add gas. Nowadays CO2 is expensive to buy in that form, for a few grammes of gas, whereas if I ferment 25 kg of sugar, I generate 12.5 kg of CO2 (for nothing) !

Bear in mind - I'm too tight to buy CO2 for my mig welder and had some hopes in that direction too ! :lol:
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Re: CO2 pressure

Post by NZChris »

As I get older I will have a similar problem. I need to lift my wash from ground level to 6' to charge the preheater. I can still do it now, but it is time to think about it. The shoulder joints creak and pop and remind me I'm getting closer to my Use By Date.

I used to use an aquarium pump sucking from CO2 stored in plastic or Mylar bags to pressurise beer fermenters for bottling, copying major NZ breweries at the time . I still use the pump, but don't bother to store the CO2 since I started krausening. For distilling, O2 exclusion isn't so important and any food grade compressed gas will do.
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Re: CO2 pressure

Post by Tomb »

Pikey:

Be prepared for a lot of naysayers if you want to collect co2.

But if you are serious...

Brewboard.com had a guy (oldfart) that took this to the point of science. (It appears he suddenly stopped contributing)

I have followed his lead and can claim all my product is naturaly carbonated. I do have a 20 pound cylinder but it is mainly for convienince at the keezer. I am now working on collecting in a 55 gal drum to max 1 bar and then compressing as needed using a "bladder tank" and compressed air.

I admit it only saves a few dollars but it adds a dimension of frugalness to the hobby.

T
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Re: CO2 pressure

Post by FuelMaker »

Capturing and compressing CO2 from your primary ferment is going to be a difficult mechanical problem. I can see why you'd want to but it'd be a toughie.

How about getting pressurized CO2 by starting a secondary ferment in a pressure vessel using something simple like sugar and tomato paste and capping it off? Let it bubble a bit first to purge the oxygen out of the vessel then seal it.

You could use a 5 gal corny keg, or maybe even a garden pump sprayer. I have no idea what kind of pressures you'd reach - or even if the yeast would end up killing themselves by dissolved CO2 in the ferment. Corny kegs are rated to 120ish PSI so they should be safe enough - though if it were me I'd still have a pressure relief safety valve and a gauge somewhere.

To keep any potential infections from transferring from your pressure vessel you'd need a .1 micron air filter in the gas line.

Edit: According to this paper https://www.ncbi.nlm.nih.gov/pmc/articl ... 0-0167.pdf 7 bar (101psi) completely inhibits yeast metabolism and 15 bar flat-out kills them. The paper is about making sparkling wine. So the pressure ferment would self-inhibit before hitting the rupture point of the corny keg.

Edit2: You'd also probably need some kind of slobber box to separate out the foam that'd generate when the pressure is released.

The more I think about it the more I think it's a neat idea - the ability to generate pressurized gas without using electric power or a foot pump. It even solves a problem of my own in generating pressure to move liquid around in a long-term power out conditions.
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Re: CO2 pressure

Post by Pikey »

Thanks for that FM - I'm thinking I'm needing to do a bit more research before I go high pressure. Basically I don't have an issue but I'm not spending huge amounts on a Corny keg, so I think I need to take some plastic out there with my compressor and see how much they can take before bursting. :shock:

I'm thinking I seriously like that bladder system - does that unit come as something you buy, or is it a bag in a barrel, home made ? My own thoughts are similar - I'll post later, when I can see properly :wink:

Edit NZ Chis - That little aqua pump - what sort of pressure can it cope with & at what sort of output / minute ? - I quite like the sound of that too :)
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Re: CO2 pressure

Post by NZChris »

Pikey wrote:Edit NZ Chis - That little aqua pump - what sort of pressure can it cope with & at what sort of output / minute ? - I quite like the sound of that too :)
I have no idea, but it is more than enough to do what I need. It's the cheapest aquarium air pump I could find, modified to give it an inlet for a CO2 line. It only has to lift 18" at the most to start the siphon, then keep up the pressure while I bottle. To lift my six gallon still charge 6' from a keg to my preheater would require pressurizing the keg to 15 psi by my estimation. That's not a lot, and there is plenty of time to recharge the keg and pressurize it between stripping runs.
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Re: CO2 pressure

Post by Pikey »

Thanks Chris - well I already have an air pump I use for aereating the wash for the aerobic ferment, so I'm sure I could press that into use. I'll modify a 20 litre container, I have a few of those which are not stamped food grade, so I can't use them for ferments, then fill it with water and see how long it takes to displace the water with air. I do want a fairly quick recharge, faster if possible than a syphon, so I'll just time it and see.

I think 15 psi (1 bar) will support a column of water 32 feet high if my O Level physics is remembered corectly, so to lift 6 ' you should only need 6/32 x 15 - or about 3 psi, plus a bit for doing the work so say 4 psi ?

My own idea at the moment has 2 more 200 litre barrelsjoined by a connacting pipe at the bottom and each with a connection at the top. One of these would be charged with water and CO2 from a secondary ferment would be used to displace the water in this barrel through the bottom connector to the other barrel. When the barrel was completely charged and holding a slight pressure, all the water would be in the other barrel and the that barrel could then be used with compressed air, to push the water bac k into the CO2 barrel which is now connected to the mash barrel. The Co2 would now push mash into my fermenter as desired.

I'm pretty sure I could make this work, but space constraints may make it impractical without adaptions to the shed. It's not terribly elegant, but there we go, I'm not very keen on going high pressure, because if we think about it a car tyre is only charged to around 2 bar (30 psi) and if we think about putting say 6 or 7 bar into one of those, I'm sure most of us would want to be in a different place at the time !
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Re: CO2 pressure

Post by NZChris »

4 psi will lift 6' ok, but I want to charge my preheater quickly and don't want to be waiting for a small pump, or low pressure, to refill the preheater so that I can put the heat back on the main boiler. I want to fill a vessel with the next charge then, when ready, open a valve, transfer it into the preheater in a couple of minutes and get the heat back on the main boiler for the next strip, all without painful reminders from my rotator cuffs that I am getting older.
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Re: CO2 pressure

Post by FuelMaker »

I dunno, I think a 5 gallon corny keg ($30 on craigslist) would be the easiest and cheapest - 4 gallons of gas over a 1 gallon ferment that's allowed to stall out at 90-100 psi. 4 gallons at 100 psi will displace 26 gallons of fluid.

BTW, it looks like a garden pump sprayer is rated for 45 PSI
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Re: CO2 pressure

Post by squeezins »

I use a small transfer pump with stainless cam lock fittings. Everything is mounted and plumbed in place. Just attach the hose and flip a switch.
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Re: CO2 pressure

Post by Pikey »

JUst wrote in the Construction section that I'm about to scrap a working freezer and thought about this thread. I wondered about using the compressor and piping as a ready made Co2 pump - ANybody know what pressure a freezer pump operates at ?
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Re: CO2 pressure

Post by acfixer69 »

Pikey wrote:JUst wrote in the Construction section that I'm about to scrap a working freezer and thought about this thread. I wondered about using the compressor and piping as a ready made Co2 pump - ANybody know what pressure a freezer pump operates at ?
It doesn't work on a pressure. It work on a pressure ratio i.e. 3:1 or 4:1 cool gas in and hot compressed gas out.

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Re: CO2 pressure

Post by Pikey »

acfixer69 wrote:
Pikey wrote:JUst wrote in the Construction section that I'm about to scrap a working freezer and thought about this thread. I wondered about using the compressor and piping as a ready made Co2 pump - ANybody know what pressure a freezer pump operates at ?
It doesn't work on a pressure. It work on a pressure ratio i.e. 3:1 or 4:1 cool gas in and hot compressed gas out.

AC
So what we sayin' - About 60 psi then ?
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Re: CO2 pressure

Post by Yummyrum »

Pikey I had a similar thought and started a topic on CCSC forum http://www.coppercustomstillcomponents. ... &hilit=Co2" onclick="window.open(this.href);return false;" rel="nofollow
Might get some ideas from it
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Re: CO2 pressure

Post by Tomb »

Pikey:

I collect co2 from a sanke keg that I ferment beer in. I let it get to about 25psi. (Above that and the yeast get unhappy. Although, once I forgot to open a valve and the pressure went way high) This means that the beer is already carbonated when it is finished fermenting so I can call it “naturally carbonated” and don’t have to wait for it to be ready to drink.

I store the extra co2 in corny kegs and a plastic drum (drum can only handle about 14 psi safely) I then compress it with a bladder tank and compressed air and store it in corny kegs at about 60psi. This is great for purging corny kegs before filling (fill with water first and then push out water with about 8psi) and moving the beer from the fermenter to the serving kegs ( one sanke to three corny)

This harvesting co2 only saves a few bucks (to fill my 20 pound cylinder costs me $30, but the trip is a couple hours and $10 in gas) but it’s part of the learning process.

Tom
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Re: CO2 pressure

Post by yakattack »

Tom. Can you post a few picks of that setup, sounds quit interesting. Would be good knowledge to have.
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