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Budweiser flatulence! well maybe not...hydrogen peroxide? > Date: Tue, 9 Feb 2010 15:30:22 -0600 > From: spm2@nomad.ignorelist.com > To: personal_submersibles@psubs.org > Subject: Re: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > When water touches Lithium I think it makes Lithium Hydroxide and hydrogen gas > (which is very bad). But aren't these things already Lithium Hydroxide? What > chemical do they turn in to when they get wet? > > Alex > > > On 09-Feb-2010 Jo Bain wrote: > > Hi, > > as a rebreather diver using Sodasorb -a lot of it! I would recomend using it > > in place of Lithium hydroxide, if Sodasorb gets wet there's a decrease in > > performance but that's it. Lithium goes BANG especially when saltwater > > contacts it...that's why tech divers use Sodasorb even though Lithium is more > > effective at removing CO2.... > > just my $0,02 worth > > > > Jo Bain > > ----- Original Message ----- > > From: Greg Cottrell > > To: personal_submersibles@psubs.org > > Sent: Wednesday, February 10, 2010 5:56 AM > > Subject: RE: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > > > If anyone is interested- Extend Air offers Co2 absorbing curtains that > > would work without the need for a fan or electricity. Each box of curtains > > would keep one person alive for about 30 hours. > > > > > > > > http://www.extendair.com/MineSafety-07.pdf > > > > > > > > Greg C > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > From: owner-personal_submersibles@psubs.org > > [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Cliff Redus > > Sent: Monday, February 08, 2010 7:42 PM > > To: personal_submersibles@psubs.org > > Subject: Re: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > > > > > Greg > > > > > > > > The link is interesting. It seems to be using the zeolite sieve not just > > for separation of the gas phases but also an absorption of the CO2 and latter > > reclamation with heat. I still think this technology is a bit of a stretch > > for a psub. > > > > > > Cliff > > > > Subject: RE: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > Cliff, Check this out: > > > > > > > > http://people.oregonstate.edu/~atwaterj/zeolite.htm > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > From: owner- personal_submersibles@psubs.org [mailto:owner- > > personal_submersibles@psubs.org ] On Behalf Of Cliff Redus > > Sent: Monday, February 08, 2010 2:00 PM > > To: personal_submersibles@psubs.org > > Subject: Re: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > > > > > Greg > > > > > > > > A molecular sieve separates the CO2 gas stream from the O2 and N2 gas > > stream by forcing the air mixture through an engineered media ( zeolite ) > > that is sized to allow the larger O2 (3.5 angstroms) and Nitrogen (3.6 > > angstroms) molecules to pass and blocks the smaller CO2 molecules (3.3 > > angstroms) from passing. So now that you have a slip stream of pure CO2 you > > have to do something with this like compress the CO2 and purge the gas out of > > the hull for figure out something else to do with this concentrated CO2 > > stream. I personally think it is to complicated for a psub and breaks the > > KISS rule. It is a better fit for a large nuclear boat. > > > > > > > > Cliff > > > > > > > > > > Cliff Redus > > Redus Engineering > > USA Office: 830-663-6445 > > USA mobile: 830-931-1280 > > cliffordredus@sbcglobal.com > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > From: Greg Cottrell <greg@precisionplastics.com> > > To: personal_submersibles@psubs.org > > Sent: Mon, February 8, 2010 12:10:21 PM > > Subject: RE: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > Hi Cliff, > > > > > > > > What do you think about using molecular sieve for CO2 removal? > > > > > > > > Greg C > > > > > > > > > > ------------------------------------------------------------------------------ > > > > From: owner- personal_submersibles@psubs.org [mailto:owner- > > personal_submersibles@psubs.org ] On Behalf Of Cliff Redus > > Sent: Monday, February 08, 2010 10:48 AM > > To: personal_submersibles@psubs.org > > Subject: Re: [PSUBS-MAILIST] CO2 Scubber Design Guidelines > > > > > > > > The easiest way to build a CO2 scrubber is to buy some SodaSorb HP (4/8 > > mesh) and use 2.2 lbs of this absorbent for every 8 hours per person in the > > boat. You pack enough of this absorbent for your normal dive into canister or > > any container with a fan and your good to go. If you follow ABS rules, you > > carry some reserve absorbent to give you an additional 72 hours of bottom > > time. For ABS rules this this means for say and 8 hour dive time plus the 72 > > hours reserve, you would need about 22 lbs of Sodasorb HP. As a check, the > > Deepwork 2000 carries 24 lbs of this absorbent. > > > > > > > > The 2.2 lbs for 8 hours comes from > > http://www.sodasorb.com/English/downloads/Sodasorb_Manual.pdf, page 16 in > > which is says "In a properly packed and well designed canister... for 8-hour > > capacity... a canister should hold approximately 1 kilogram of (2.2 pounds) > > of SodaSorb absorbent". > > > > > > > > On my boat, I picked a canister size to meet my normal mission time and > > then played around with different fan motors until I found a fan size that > > would circulate the cabin air through the canister without pulling so much > > current that it would drain my emergency battery bank before I reached the 72 > > hours limit. > > > > > > > > While this worked fine, I wondered about what a "properly packed and well > > designed canister" meant. I recently came across an excellent technical > > report that goes into a lot more detail on this subject. It is titled > > "Design Guidelines for Carbon Dioxide Scrubbers", (May 1983, revised July > > 1985) by M.L. Nuckols, A. Purer and G.A. Deason of the Naval Systems Center , > > Panama city Florida . > > http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA160181&Location=U2&doc=GetTRDoc.pdf > > > > > > > > This goes into the impact of design variables such as temperature, > > pressure, canister length and diameter, relative humidity, CO2 concentration, > > flow rate through the canister and particle size. The experimental work > > sited in the paper is for SodaSorb. While this report was written for > > designing re-breather canisters operating at elevated pressures that a diver > > would see, it does handle the limiting condition of 1 atm that we would see > > in a 1-atm. psub. > > > > > > > > So if you need a little "light" reading while your doing your business in > > the morning, you might want to have a read. Now if we could just get someone > > to drop this into an excel spreadsheet, we would be in business. > > > > > > > > > > > > Cliff > > -- > Mailed with XFmail on 09-Feb-2010. > God saved Noah, but Noah had to build an ark! > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. 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