Liquid vs vapor CO2?

[Clare]

Hello All,

My newb question is two-fold:
1. For those of you who inject via a reactor in a sump, how much CO2 do you tend to use? ie. how long does your cylinder last?
2. Does anyone use liquid CO2 in their cylinders?
3. Any tips on converting CO2 weight to volume?

I'm in a pickle! My large CO2 cylinder has run out, and the supplier says there is a CO2 shortage and can't replace it in the foreseeable!
....I got a small 4.5 kg cylinder from a home brew supplier, and it ran out overnight, (with no change on the drop checker!) which has forced me to look in to what is going on!

...My large cylinder was liquid CO2 (I rang the company to work out why my gauges said it was empty!), so I assumed that was what everyone used! It contained 6kg of liquid CO2. It lasted me about 3 months.

....the small cylinder I have is 4.5kg. I now assume this must be CO2 as a gas.

I titrate the CO2 by measuring how many mls/min I have flowing in to the reactor (rather than bubbles per sec, as it's way high much to count) aiming for around 60ml/min (as recommended by others).

Thanks for any advice!

 

[Immortal1]

To the best of my knowledge, all CO2 cylinders use liquid CO2 - generally around 900psi in the tank. When the liquid CO2 (which vaporizes to a gas as it looses pressure) runs out in the CO2 tank, you will notice the pressure begins to drop. This indicates the liquid is gone and only the gas remains.
6kg (or 13 pounds) of liquid CO2 lasted you about 3 months. I have a 10 pound CO2 tank feeding a 40 gallon and a 75 gallon - lasts 2.5 to 3 months as well.
Hmmm, CO2 weight to volume. There should be a conversion, but I don't know what it is.
As for the 4.5kg CO2 tank - I would guess what you got was basically an empty tank (no liquid). In your case, (or mine), I would weigh the empty CO2 tank and mark that on the tank somewhere. If they (someone) re-fills the tank it should increase in weight by how much you bought - i.e. my 10 pound rated CO2 tank gets 10 pounds heavier when they re-fill it.
For my 75 gallon tank I am running about 35 to 40 standard cubic centimeters per minute (sccm) as measured by a lab grade flow meter. Not sure how that relates to your 60ml/min.

 

[klibs]

For my 75 gallon tank I am running about 35 to 40 standard cubic centimeters per minute (sccm) as measured by a lab grade flow meter. Not sure how that relates to your 60ml/min.

What flow meter are you using to measure CO2 injection?

 

[Immortal1]

What flow meter are you using to measure CO2 injection?

I run my regulator at 20psi

 

[GreggZ]

Hello All,

My newb question is two-fold:
1. For those of you who inject via a reactor in a sump, how much CO2 do you tend to use? ie. how long does your cylinder last?
2. Does anyone use liquid CO2 in their cylinders?
3. Any tips on converting CO2 weight to volume?

I'm in a pickle! My large CO2 cylinder has run out, and the supplier says there is a CO2 shortage and can't replace it in the foreseeable!
....I got a small 4.5 kg cylinder from a home brew supplier, and it ran out overnight, (with no change on the drop checker!) which has forced me to look in to what is going on!

...My large cylinder was liquid CO2 (I rang the company to work out why my gauges said it was empty!), so I assumed that was what everyone used! It contained 6kg of liquid CO2. It lasted me about 3 months.

....the small cylinder I have is 4.5kg. I now assume this must be CO2 as a gas.

I titrate the CO2 by measuring how many mls/min I have flowing in to the reactor (rather than bubbles per sec, as it's way high much to count) aiming for around 60ml/min (as recommended by others).

Thanks for any advice!

If I were you I would look for other suppliers. I just got my CO2 tank filled and no mention of a shortage. Try a local Fire Equipment provider. They fill up extinguishers all the time.

For reference on usage I run my CO2 at about 45 cc/min 8 hours a day and a 10lb CO2 tank lasts me about 10 to 12 weeks on average.

The best thing to do is to get a spare cylinder. When my CO2 runs out there is no rush to fill as I always have one filled and ready. To me it's worth the convenience and the peace of mind.

 

[Art]

As @GreggZ mentioned, look for alternatives. I've obtained CO2 from beverage, fire equipment and medical companies. I haven't heard of a CO2 shortage, at least in the US.

I too use 2 cylinders to avoid an emergency because I've had too many of those before. It buys me time to do a refill on my time rather than as an urgency.