Prototype of CO2 scrubber

Discussion in 'General Homesteading & Building' started by bunkerbob, Dec 1, 2009.

  1. bunkerbob

    bunkerbob Supporting Member

    Here are a few photos of the CO2 you can see this will attach with a male thread adaptor to the 4" sweep just before the AC fan and hand cranked fan. It can be opened and closed as necessary via the blade valve, and the lid can be opened to change out depleted contents. The lid is perforated to allow air in.
    Last edited: Nov 29, 2010
  2. Jerry D Young

    Jerry D Young Well-Known Member

    Great job! I've been looking for ideas on how to do something similar. What is the bowl container made from?

  3. bunkerbob

    bunkerbob Supporting Member

  4. TechAdmin

    TechAdmin Administrator Staff Member

  5. bunkerbob

    bunkerbob Supporting Member

    I had posted more detailed photos of it but was somewhat hesitant, I replaced them with that one. I take responsibility for my own use, if someone wants to duplicate thats ok with me, but, also do your own research first. Sorry if this sounds weird.
  6. TechAdmin

    TechAdmin Administrator Staff Member

    Don't think you would be held liable but its completely your call Bunkerbob. Thank you for sharing!
  7. JeepHammer

    JeepHammer Well-Known Member

    I have to assume this is in the event of chemical, biological or nuclear attack,
    All of which is VERY unlikely...
    In that case, you would want to seal off a room and have POSITIVE PRESSURE in the room to keep contaminants out.

    This constitutes a 'Pressure Vessel', and all rules apply same as any pressure vessel.

    I scuba with a re-breather (Draeger Mk V), and the material there will only SCRUB the CO2,
    There is NO ADDED OXYGEN to replace the depleted oxygen your body used...
    The Re-breathers add oxygen to the mix as needed from an O2 tank on board the scuba frame.

    The training to use one CORRECTLY IS EXTENSIVE!

    If you are in a LARGE, SEALED SPACE,
    Then there is enough extra oxygen to keep you going for a while, but there is NO WAY to seal a large space for positive pressure unless you have the shipyards build it for you,
    And again, it will have to conform to pressure vessel standards.

    But you WILL need to add O2 eventually or YOU WILL DIE...

    The chemical is 'Soda Lime', and medical grade soda lime should ONLY be used by someone that knows EXACTLY what they are doing...

    Medical grade soda lime changes color as it absorbs CO2,
    But Divers don't use the dyed version since it's suspected that the dye was poisoning divers when under pressure.
    (Remember that positive pressure thing you need to keep contaminants out? If not, keep reading...)

    A simple indicator is used to keep track of CO2 and Oxygen content.
    (Field expedient version can be rigged from a vehicle O2 sensor and volt meter)

    For a small room size containment "Vessel"
    ("Vessel" being proper usage for a sealed environmental chamber)
    One should have a 'Chest' size container, around 30 pounds, of soda lime for a 5 hour containment.

    44 Lbs. of life support grade soda lime will run you about $180 with a $45 ground shipping fee.

    Medical grade that changes color is about $40 a pound.

    CONSTANT checks on O2 and CO2 levels will be necessary,
    And automatic alarms and/or automatic provisions for rescue in the event of unconsciousness should be in place!
    (IE, dead man's switch to ventilate and rescue your butt if you loose consciousness!)

    Adding oxygen or other INERT gasses will create 'Positive Pressure' in your 'Vessel' and positive pressure keeps contaminants from entering.

    Inert in regards to the effect they have on the human body, most of which are EXPENSIVE.

    Doors/windows MUST be sealed and pressure rated,
    And doors should be "Double Sealed'...
    that means an external seal when the door is 'Dogged',
    (Like a large 'O' ring)
    And an internal seal between door and frame, which is usually greased/inflated to fill the gap completely between door and frame...

    Internal window needs to be sealed to the INSIDE of the vessel, with a good seal, and the window MUST be pressure resistant or it will blow out with just a few psi of pressure internally.

    The outer window (should there be one) needs to be sealed to the OUTSIDE of the vessel.
    Usually, alcohol or other liquids are used between windows to ensure a seal is kept,
    Leaks will show up as air space between windows.

    The vessel can't be built out of anything rigid!
    Concrete will give way at about 3 psi no matter how thick.
    Steel liner that DOES NOT touch walls is best,
    But even some fiberglass tanks will work as 'Pressure Chambers' or 'Containment Vessels'

    Long exposure to even low pressure (1-5 psi),
    Can give you the "Bends" when you decompress.
    Decompression should be done VERY CAREFULLY to avoid bubbles forming in the blood stream that can attack organs, nervous system, even cause clots, strokes, ect.


    There are a LOT of ugly things that can happen when using pressure vessels,
    And if you are NOT using a pressure vessel,
    Then there shouldn't be any need for re-breather...

    Medical grade HEPA filters would be MUCH cheaper and more efficient for partial filtering and you would have positive flow that wouldn't be as claustrophobic.
    (HEPA: High Efficiency Particle Arrestors, very common and easy to use)
    Last edited: Mar 31, 2010
  8. bunkerbob

    bunkerbob Supporting Member

    Jeep here are some of the system specs and equipment I have in place and also some of the research I've done:

    Carbon Dioxide Information Analysis Center (CDIAC) - Frequently Asked Questions No Longer Online

    I'm presently do some research into CO2 scrubbers using Sofnolime(from underwater re breather systems) and pelletized carbon. These would be important in a sealed shelter situation. What I can gather that Air contains about .04% CO2 and the normal adult exhales about 5.7% CO2.
    3000ppm would be a minimum accumulation
    5000ppm could cause discomfort an or headache
    50000ppm could cause intoxication
    70000ppm-100000ppm could cause loss of consciousness

    1 kilo grams or 4 cups of Sofnolime absorb about 144 liters of CO2

    Reaction of Sofnolime is as follows:
    CO2+H2O----H2 CO3
    H2 CO3+2 NaOH----Na2 CO3 + 2 H2O
    Na2 CO2 + Ca(OH)2----CaCO3 + 2NaOH
    Thus changing CO2 into carbonic acid then neutralizing it.
    The Sofnolime changes from white to a bluish purple color when saturated.

    The pelletized carbon will absorb a plethory of toxins and gases.
    The canister, which holds 4 cups of Sofnolime and 2 cups of carbon, is clear acrylic which will enable visual indicators when new one is needed. It also can be readily opened to refresh the contents.

    looking into these:
    CO2 Meter | Indoor Air Quality Products - Welcome
    Nellcor Easy Cap II CO2 Detector- Each
    Cellarsafe mains powered CO2 and O2 Detector -
    Found and purchased reasonable priced sofnolime:
    Molecular Products 5 Gallon Pail Sofnoline® 2550 USP Grade Sodalime -

    And as you can see in the photos I have a O2 tank to replenish The O2 in the event I have to seal (ie the 4" stainless steel blade valves) the shelter. I use a clear CO2 canister so I can see when the sofnolime changes color when saturated and needs to be changed along with the pelletized carbon. I also have 2-300cf high pressure air cylinders to provide positive pressure if need be and positive pressure does not have to be that high to work. My estimate is that the 2 tanks will last about 18hrs with a slow release of air. The shelter still needs the UV high intensity lamp still, but the MERV 13 and carbon filters are in place, as well as lightly oiled copper wool outside filter material.
    One photo shows my whole house filter system, and yes I will still seal the external openings with duct tape and 2 mil plastic. The filter consists of 2 outside HEPA filters, then into a chamber of UV high intensity light, then to a MERV 13 rated HEPA filter, continuing thru a carbon foam filter.
    All of this prep and multiple NBC masks, full containment suits, and decom gear should provide enough protection.
    All of this is in place now and ready to use.

    Attached Files:

    Last edited: Apr 1, 2010
  9. JeepHammer

    JeepHammer Well-Known Member

    Man! You really are ready for NBC attack! :congrat:

    Personally, if NBC hammers my area (unlikely since we are WAY out in the 'Boonies') I'm DEAD! :surrender:

    My experience is with military NBC and scuba, sometimes mixed gas and decompression.

    The medical grade SodaLime you are using (Changes Color) we don't use in scuba anymore.
    Navy divers were getting some serious health problems linked to the dyes in the medical grade soda lime,

    We use un-dyed soda lime now for that reason in our re-breathers. No color change.
    The body acts very differently to chemicals under intense pressure than it does at atmospheric pressures, so we don't introduce the chemicals that do the color change to the life support anymore.

    The only issue I have with a plywood 'Shelter' is you can't pressurize a plywood structure.
    It's like concrete, just too permeable, while concrete is too brittle to use as a pressure vessel.

    Seems like it would take a LOT of volume to keep positive pressure in a plywood structure (safe room), and all the volume you have to take from outside would exponentially increase the chances of infiltration of toxins (NBC) from outside to keep the pressure up...

    Anyway, I've been out of it a LONG time, I haven't been an NBC officer since '94, so I'm long out of practice...

    Looks like you are ready in any situation!
    Personally, I would have gone with a cargo container or old pressure tank, like one of those giant propane tanks cleaned out,
    And sealed it up to hold about 2-3 psi over atmosphere...

    Since radiation can't turn corners, a shielded 'Zig Zag' inlet tube keeps direct radiation out,
    Shielding can be anything up to and including a buried PVC tube that 'Zig-Zags'....
    Earth makes a GREAT radiation shield!

    Most radiation issues will be from contaminated particles, and HEPA filters will stop most particles down to .3 microns,
    And that's small enough to stop bacteria and most viruses.

    Medical Grade UV kills ALL biologicals,
    I use UV to purify my raw water, and it works WELL!
    4' of Medical grade UV tubes eliminated 100% of biologicals in my drinking water, so it's VERY effective if you can keep exposure time up enough to do the job.

    Then it's just an issue of 'Gas'...
    Which most will be stopped cold by carbon filters, so it looks like you have thought of everything!

    I use sand filter barrel for water, then charcoal, then UV.
    Biologicals were 100% eliminated, so were all heavy metals, with just traces (well below 'Safe' standards) of chemicals which you can't avoid entirely unless you have deionized water...

    I figure my re-breather/scuba tanks will keep me alive until a farm chemical spill dissipates or I can get clear of the area,
    And in an all out military strike/area saturation attack, I wouldn't want to live there anymore anyway!

    We DO occasionally have the odd ammonia spill around here (farm chemicals), but I normally don't plan to live long term (or even short term!) in a NBC environment!
  10. bunkerbob

    bunkerbob Supporting Member

    The shelter is below ground under my workshop slab, dug into DG(decomposed granite) almost as dense as rock.
    The home bunkerbob is ICF block, 2 1/2" foam on each side and 6" core of steel reinforced concrete. The exterior is Hardie concrete siding and the interior walls and ceiling are 5/8 drywall. When walls are poured the concrete actually comes in contact with the slab, thus sealing the bottom. Rebar is embedded in the 3'x3' footings which extend the full height of the 9' walls, 37 yards of concrete later the walls were finished. Even the garage is ICF block walls, the house will take a rictor 10 earthquake. The wood truss system is bolted to the walls with 3/8" 'L' brackets via 5/8" bolts embedded in the concrete.
    I used tech shield OSB sheeting for the roof, this has a metal foil surface on the inside to add an insulating factor and add some EMP protection. This is also grounded to the UFER ground rod in the slab.
    We tried the system and it showed a change on the barometer inside, showing that is was indeed pressurized, not much but some.
    Always working to make it better and learning more on the forum.
  11. NaeKid

    NaeKid YourAdministrator, eh?


    I believe what you are seeing is only one part of the underground bunker that BunkerBob has created which is completly surrounded by solid earth and a concrete cap. The plywood sheeting just makes things a little easier to mount, and, it hides the dirt behind it.
  12. bunkerbob

    bunkerbob Supporting Member

    The photos show the sides of the DG that I dug out, I guess it looks like plywood, but no plywood in shelter at all. The only wood right now are the 4x4 beams.
    I changed the photo to explain what you are looking at.
    Last edited: Apr 1, 2010
  13. NaeKid

    NaeKid YourAdministrator, eh?

    Thanks for that clarification there Bob.

    BTW: Looks like we both posted at the exact same time to JeepHammer's response ;)
  14. NavyKen

    NavyKen Active Member

    JeepHammer you made some good points but I'm in the US Navy and all our ships are equipped with a CPS (Collective Protective System) this is where the ship has air locks and the inside of the ship is pressurized at all times while at sea and the bends is not a concern. The amount of pressure is extremely low only a few pounds just enough to ensure that the air from any leaks is always flowing out of the ship. the are coming is is hepa filtered and charcoal filtered thus no CBR contaminates.

  15. HarleyRider

    HarleyRider Comic Relief Member

    Bunkerbob... you da man!!!

    Bunkerbob, I am really impressed! You seem to have thought of EVERYTHING and definitely have my respect. No wonder your posts are so informative.
    Thanks for sharing your knowledge with us newbies. :congrat::congrat::congrat::congrat:
  16. bunkerbob

    bunkerbob Supporting Member

    Thank you for the acknowledgement, hard work, that's all, wish more would do likewise in this nation.
    Its kinda going slow lately on the power room addition to the 'pit', with all the canning, gardening, and reloading.
    By the way the batteries I just acquired are fantastic, the AGM deep cycle type are the bomb, added 12 to my off-grid power system and planning to put 10 in the power room.
    I have set up the air system in the 'pit' to come on 15 min every hour until 6pm then shut down until 6am to keep the air fresh and recycled, the plants are doing fine with the LED panel and the full spectrum CFL bulb growing as if in sunlight. I plan on expanding the type to air filtering plants later.
  17. The_Blob

    The_Blob performing monkey

    I just had a terrible thought...

    you didn't buy CHINESE drywall, did you? :gaah: