Filling High Pressure CO2 Tanks From Fermentation

Taking care of your health just got easier, thanks to my sponsor Zocdoc — start here at: https://zocdoc.com/hyperspace

In this video I'll show how to capture the Carbon Dioxide generated during alcohol fermentation and use it to fill high pressure tanks as a liquid. This is sort of a follow-up to my last video where i fermented sugar to ethanol and used it to run a generator. Approximately half the mass of the sugar gets converted to CO2, and normally it's just wasted by venting out into the atmosphere, but bottled CO2 has tons of practical uses:

-A compact pneumatic source
-Paintball propellant
-Beverage Carbonation
-Refrigerant
-Fire Extinguishing
-Several applications as an "inert" cover gas to shield against oxidation

There's a lot more applications than that but those are just a few common ones. At room temperature, liquid CO2 has a density of about 0.77g/cc, which makes it extremely convenient as a pneumatic source, because a single liter of liquid CO2 can fill about 430L of volume when it's discharged as a gas. The only catch is that to be liquid at room temperature requires a pressure of around ~64 bar absolute or 910 PSIG. A regular shop compressor can't achieve this pressure, so either a high pressure compressor would have to be utilized, or this would need to be done at a lower temperature. By using a vapor compression system filled with propylene, I was able to reduce the temperature of the bottle being charged to about -33C, meaning only about ~13 bar absolute or 175 PSIG was required for condensation, making this possible for an ordinary shop compressor. However, I found that the fill rate at this pressure was extremely slow, so I opted to use a refrigeration compressor instead, which could easily deliver 400-500 PSIG, which rapidly filled a 20-oz paintball CO2 tank at -33C.

The small CO2 bottle was able to lift my F150 truck about ~200mm on its rear suspension, but the actuator I was using didn't have a long enough stroke to lift the rear wheels clear of the ground. The bottle was also able to run a pneumatic motor connected to a generator for several minutes, but the extreme temperature drop caused challenges in maintaining pressure. Obviously the liquefied CO2 can also be used for making dry ice, but it's usually best to do this at a lower temperature to improve efficiency.

I plan to use this method to charge CO2 bottles for ballast gas when I make part II of my Kayak Submarine Video.