Need help identifying equipment to reduce CO2 emissions from a small brewery

how ironic, I was just asking this question at one of our local brew pubs. The CO2 that they buy to carbonate with comes from wells that were drill 50 years ago. These wells produce 9.99% pure CO2. The bottler uses a process that they claim is secret to make "food Grade" or "Beverge Grade" CO2. First off, the CO2 needs to be dried witha silca gel or mole sieve. Next an activated carbon would remove most contaiminates. The CO2 could be compressed by an oilless sanitary compressor and the stuff stored until its time to carbonate the next batch.

You should definately have enough CO2 coming off fermentation. I home brew too and it takes about 1 cup of sugar to produce enough CO2 to carbonate 5 gallons of beer that has already consumed 6 pounds of sugars.

How about that? Just build a tank that is sanitary, throw in some yeast and sugar. seal the tank up, the yeast work untill the tank has 50 psi on it, then use it. It would be a semi batch process with two tanks.

Bill Velek wrote:

snip ...
> First off, the CO2 needs to be dried with a silca gel or mole sieve.

I would suspect that many different dessicants could be used.

> Next an activated carbon would remove most contaiminates. The CO2 be
> compressed by an oilless sanitary compressor and the stuff stored
> until its time to carbonate the next batch.

I've thought of feeding a bladder tank from the fermenter until the bladder is full, switch to an empty bladder, and then use hydraulics or a high pressure pump to fill the bladder tank with liquid (on the side without the CO2), compressing and forcing the CO2 into a storage tank.

> You should definately have enough CO2 coming off fermentation. I home
> brew too and it takes about 1 cup of sugar to produce enough CO2 to
> carbonate 5 gallons of beer that has already consumed 6 pounds of
> sugars.

_Possibly_ enough ... but at least enough to make a HUGE difference in the amount of CO2 needed to be purchased. Aside from purging lines with it, you need enough volume to displace the liquid in any tank being emptied (this should be retrievable if you have the equipment to do it), while maintaining constant pressure as a tank is being transferred into any packages (kegs, bottles, cans) -- and that should be retrievable, too. You also need enough to purge any vessels that you are filling (NOT retrievable), and if you are canning you also need to blow CO2 across the tops of cans as the lid drops in place (NOT retrievable), and it might be the same with bottling. And then, of course, you have the volume of beer needed to carbonate the beer, too (NOT retrievable).

Okay, this is where I can use a bit of help; I'm not a scientist, and there is a lot that I don't know or understand, so please correct me.

Let's assume that you have a 50 barrel tank and you want to carbonate the beer to the typical 2.5 to 3.0 volumes of CO2 at 30F/-1C prior to filling containers (a small drop will occur during the filling process, so we overcarbonate at this stage), ... but let's use 2.7 volumes as a good target. When full, the tank will contain 2.7*50= 135 barrels of CO2 dissolved in the beer (let's assume no 'head space' for simplicity). As the beer is drained, it is draining CO2 with it, but to maintain the pressure at 2.7 volumes of CO2 so the beer won't outgas and foam while filling, we need to completely fill the tank with another 135 barrels of CO2 at the same rate that the beer is being drained. But that part should be retrievable with appropriate equipment, to be used for
carbonating the next 50 barrels of beer.

Now, to fully purge containers equivalent to 50 barrels requires 50 barrels worth of CO2 at atmospheric pressure, and a bit more to blow the surface as lids/caps go in place. Depending upon how equipment is adjusted/calibrated, that could be a bit more (wasting CO2) or a bit less (risking oxidation during storage). Let's assume that 110 percent of volume does the trick, so we'd need 55 barrels of CO2 for purging, none of which is retrievable.

But there is one other factor involved -- the level of dissolved CO2 in beer prior to forced carbonation. This will vary with fermentation temperature, altitude and barometric pressure, how quickly the beer is transferred after fermentation is finished (it will eventually go completely flat if it sits long enough), and possibly other factors. But let's assume an ale fermented at sealevel at a nice temperature of 65F; I can't find a chart on it, but I think it is a safe bet to assume that it will be close to 1-volume of gas if transferred immediately when fermentation ends. If there is any pasteurization or filtering prior to forced carbonation, that could possibly reduce CO2 saturation, but I will ignore that at this point.

This is where I'll probably mess up because I don't think volumes of gas versus temperature and/or pressure is a linear function; please help.

_WITHOUT_ any retrieval of CO2, we would have 50 barrels of beer already containing about 1-volume of CO2, to which we would need to add 1.7 volumes (1.7*50= 85 barrels) to reach our target carbonation; then we would use 2.7 volumes (2.7*50= 135 barrels) to displace the beer during transfer, and then another 1.1*50= 55 barrels for purging. So, a _rough_ estimate is that we would need at least 275 barrels of CO2/50-barrel batch if we can't retrieve CO2 ... but only 140 barrels if we CAN retrieve it.

My overly simplistic view is telling me that 275 barrels of CO2 equals 32,270.53 liters / 22.4 liters * 44.01 grams = 63,403grams = 63.4kg = 139.77 pounds/50-barrels, so for a 5,400 barrel/year brewery, it ought to require just 15,095.16 pounds of CO2. This doesn't come anywhere close to the amount the two cited breweries use, so either I'm making a big error somewhere, or else they are both wasting a lot of CO2 or have other uses that I've not accounted for.

A critique would be very much appreciated; thanks.

> How about that? Just build a tank that is sanitary, throw in some
> yeast and sugar. seal the tank up, the yeast work untill the tank has
> 50 psi on it, then use it. It would be a semi batch process with two
> tanks.

I don't know the threshhold limit for yeast surviving under pressure, plus you'd produce ethanol that you'd need to get rid of; perhaps add a distillery and use the ethanol as fuel. ;-)

Cheers.

Bill Velek -- portal to my "HOMEBREWING" sites: www.tinyurl.com/29zr8r
My other sites: www.velek.com ~ www.2plus2is4.com ~ www.grow-hops.com

"...or else they are both wasting a lot of CO2..."

If I were a betting man, that's where my money would go! Don't forget to calculate the cost of the retrieval equipment versus the savings in purchased CO₂ because even though you may be helping save the planet, if you go out of business because it isn't cost-effective, the good you do will end there. I'm not so sure you'd need to dry the emissions, because the compression of the gases will freeze out some things (like water) and leave the volatiles (like ethanol) behind. Presuming you plan to go all the way to "dry ice" for economy of storage, that is...

EnviroMan wrote:

> (Bill Velek previously wrote:)
>> "...or else they are both wasting a lot of CO2...">

> If I were a betting man, that's where my money would go!

Well, I could be wrong about things like the volume needed for bottling or canning. I just made an assumption that the machinery would inject just a little more than the volume of the bottles/cans, but it might be designed to use two or three times that much to be certain that as much air (oxygen) as possible is removed prior to and during filling; that alone could explain a lot of the difference, plus one the brewers mentioned later that he used CO2 to push his beer from vessel to vessel instead of using pumps. While one might suppose that this would be done anyway as part of the purging process, I can see how an extra volume is used that way. E.g., 2.5 volumes of CO2 under pressure is forced into a fermenter to push it into a brite tank, and then the fermenter is opened for cleaning and sanitizing, thereby venting the CO2 to atmosphere. So I wouldn't presume that these brewers are necessarily wasting very much; I was just rather shocked at how much they use, but I never really did any calculations.

> Don't forget to calculate the cost of the retrieval equipment versus
> the savings in purchased CO2 because even though you may be helping
> save the planet, if you go out of business because it isn't
> cost-effective, the good you do will end there.

Roger that!!

The considerations should be:Cost of CO2 plus storage tank plus footprint for tank, versus cost ofretrieval equipment and any storage tank, plus maintenance costs, plusfootprint, along with any labor involved plus power to operate it andsupplies used, such as any dessicant and activated carbon. But first Ineed to locate the equipment.By the way, I haven't checked with any supplier _YET_, but the cost forone brewer is 12 cents/pound, although that could vary a lot for medepending upon shipping distance, etc. But to demonstrate its possiblepracticality, a 15,000 barrel/year brewery using the conservative figurequoted by one brewery will needs 5,000 pounds/week = 260,000 pounds/yearat a cost of $31,200 per year at 12 cents/pound. So even if the recoveryequipment costs a hundred grand, it would probably be worth the money.

> I'm not so sure you'd need to dry the emissions, because the
> compression of the gases will freeze out some things (like water) and
> leave the volatiles (like ethanol) behind.

The only reason I'd worry about any water content possible corrosion of the storage tank; I realize that there won't be any oxygen to assist with corrosion, or at least we would be doing our best to remove the oxygen because that's the whole purpose in using CO2 -- to protect the beer from oxidation. But I assume the CO2 and water would make carbonic acid, although I don't know the affect on metals. I would want to get rid of the volatiles.

> Presuming you plan to go all the way to "dry ice" for economy of storage, that is...

Well ... probably liquid CO2. Under pressure, there is a liquid state, but as long as I can put CO2 _gas_ into storage and then remove _gas_ when I need it, I don't care if it's solid or liquid. And actually, by using an on-going process of consuming it about as fast as it's produced, all we might really need is just a pressurised tank without even bothering to liquify it.

Thanks for the feedback. Cheers.

Bill Velek -- portal to my "HOMEBREWING" sites: www.tinyurl.com/29zr8rMy other sites: www.velek.com ~ www.2plus2is4.com ~ www.grow-hops.com

Not affiliated with any of the following: With that said, there are many suppliers that provide CO2 recovery systems. The problem is will they be willing to work with a "small" brewer. Of the ones I have worked with, Huppmann, Steinecker, Whittemann, Haffmans, etc, Whittemann is the only one I have seen work with Micros and Pub brewers.

Are you venting to atmosphere during the entire fermenting process? If so, maybe you can look at "Bunging" or "Pigging" your tank after kraeusening in order to carbonate your product and see some immediate CO2 reduction to atmosphere.

Typically, with a balanced system, you can recover sufficient CO2 from your fermenting operation to never have to buy CO2 again. And, depending on your volume, may be able to sell it back to other industries. However, even a simplified system requires investment. You need to mechanically collect your CO2 through a piping system and send it to a foam trap or a bladder where it will be flushed (Scrubbed) with water to remove / absorb water soluble impurities and aerosols. Then the gas needs to be sent to a two tank dryer / filter where it will be dried and cleansed with activated carbon. Afterward, the gas needs to be passed through a shell and tube heat exchanger to remove any inert gases i.e O2 and N2. A compressor will be needed to compress the gas. The compressed gas will be liquefied in a condenser and stored in a tank until usage demands. I have obviously simplified the process, but I just wanted you to get an idea of the equipment involved. I would call Wittemann and ask there opinion.

Note: Some information taken from GEA Brewing Handbook

'rurudr' wrote:

> ... Of the ones I have worked with, Huppmann, Steinecker, Whittemann,
> Haffmans, etc, Whittemann is the only one I have seen work with
> Micros and Pub brewers.

Yes, I have already been to the Whittemann website which indicates that they do work with smaller breweries, so they might be our only choice. Thanks for the other possible leads.

> Are you venting to atmosphere during the entire fermenting process?
> If so, maybe you can look at "Bunging" or "Pigging" your tank after
> kraeusening in order to carbonate your product and see some immediate
> CO2 reduction to atmosphere.

I assumed (haven't had time to check yet) that pasteurization and filtering would substantially reduce saturated CO2, but there will probably be some to help a bit.

> Typically, with a balanced system, you can recover sufficient CO2
> from your fermenting operation to never have to buy CO2 again. And,
> depending on your volume, may be able to sell it back to other
> industries.

Perhaps excess can be used to refill CO2 tanks for customers who buy in kegs, but I don't want to get into another segment of industry that might require different inspections, etc. E.g., we might be required to do hydrostatic tests on tanks, which would probably make that sort of a sale of CO2 more trouble than it would be worth.

> However, even a simplified system requires investment.

If we're talking about less than $100k, we would consider it. With the possibility of needing to purchase as much as $30,000/year of CO2, we would need to be able to amortize the capital investment from that.

> You need to mechanically collect your CO2 through a piping system and
> send it to a foam trap or a bladder where it will be flushed
> (Scrubbed) with water to remove / absorb water soluble impurities and
> aerosols. Then the gas needs to be sent to a two tank dryer / filter
> where it will be dried and cleansed with activated carbon. Afterward,
> the gas needs to be passed through a shell and tube heat exchanger to
> remove any inert gases i.e O2 and N2. A compressor will be needed to
> compress the gas. The compressed gas will be liquefied in a condenser
> and stored in a tank until usage demands. I have obviously simplified
> the process, but I just wanted you to get an idea of the equipment
> involved. I would call Wittemann and ask there opinion.

Understood. Whittemann has a flow-chart here: http://tinyurl.com/6xzvvr

> Note: Some information taken from GEA Brewing Handbook

What is "GEA"?

Thanks for your response and suggestions.

Bill Velek

GEA might refer to: http://www.geabrewery.com/

Hey, just another thought as I re-read your post. You say "Aside from purging lines with it, you need enough volume to displace the liquid in any tank being emptied ". If you "play" with it a little, you will find that you can put a blanket of CO2 on your tank and continue your emptying by pushing with sterile air. The blanket of CO2 will be sufficient to keep the air from penetrating into your product. You can also push product with process water. I good eye and a sight glass will let you know when your unfinished beer has made it to filtration. Or you can spend the money and put in an inexpensive meter.

GEA is the parent company of Tuchenhagen and Huppman supplying products and services to the food and beverage industries. I have some of there ref. material laying around from years of collaborating on brewery projects.

'rurudr' wrote:

> Hey, just another thought as I re-read your post. You say "Aside from

> purging lines with it, you need enough volume to displace the liquid

> in any tank being emptied ". If you "play" with it a little, you will

> find that you can put a blanket of CO2 on your tank and continue your

> emptying by pushing with sterile air. The blanket of CO2 will be

> sufficient to keep the air from penetrating into your product. ...

With all 'due respect' to you and the 99% of homebrewers and others who seem to believe that there is some sort of an impenatrable layer of CO2, I'm pretty sure that you are wrong. It is my understanding that each and very gas, irrespective of any other gases in the area, attempts to equalize in pressure and fully disperse itself within any confines that it finds itself. And if that is not true, then it seems to me that wewould have a thin layer of CO2 covering the surface of the earth.So, for example, if you have a mixture of 99% CO2 and just 1% oxygen within a headspace, you will not have pure CO2 on the surface of the wort, and a tiny bit of oxygen at the top, but rather you will have 99% CO2 and 1% oxygen throughout the volume of gas (e.g., the "headspace"), with that 1% of oxygen trying to dissolve within the wort, which would eventually cause oxidation.

> ... You can also push product with process water. I good eye and a

> sight glass will let you know when your unfinished beer has made it

> to filtration. Or you can spend the money and put in an inexpensive

> meter.

I'm 'pretty sure' that pushing a liquid with a different liquid is apt to mix the two of them to some degree.

> GEA is the parent company of Tuchenhagen and Huppman supplying

> products and services to the food and beverage industries. I have
> some of there ref. material laying around from years of collaborating

> on brewery projects.

I'm pretty sure that you are correct, and I have found their website and have begun to study their material.

Cheers.

Bill Velek

I believe you are correct about both gases and liquids mixing, especially when pressure is applied. Fuel pipelines have this concern when they pump different grades like gasoline, jet fuel, etc. They end up with intermediate blends that have to be downgraded.