We have been working on a case study that compares our TCS against CO2 / dry ice / chillers and are interested in knowing how much you are consuming (co2 / dry ice) at how many kw (heat) to recover how much solvent or chill how many columns? I have never really focused on consumables to run a system and as a result have become very familiar with chillers, and all the problems associated with them, but not so familiar with co2 / dry ice consumption.
Additional info that would be greatly appreciated is the inlet and outlet temperature of the column, along with the volume of solvent per minute (or other known time-frame), and the solvent mixture. From here I can calculate the general cooling capacity of your system knowing this information.
So far, our electrical savings are coming in right at 93.37% compared to chillers. I am excited to see how we compare against co2 and dry ice!
I went ahead and picked up a couple 20lb tanks of co2 and transferred it to an extraction column at about 100psi to keep it from forming dry ice. After that I had depressurized to around 50psi or so to get it cold; just under the triple-point.
From what I can tell, the 40lbs of liquid CO2 only filled the 6x48 column jacket to just under half way where it was reading below -50c, then only had a half life of about 30 minutes, and was pretty much completely gone in an hour or so.
This would put it at right around 100 lbs of co2 per 6x48 jacket per hour to maintain below -50c. That is pretty outrageous to have to supply that kind of volume to run a machine… To compare, our two column Turbo Max, that has its own <-50c refrigeration system contained, would comparatively require around $150k of co2 per year on the extreme low side and upwards of something stupid on the high side. The Behemoth would then come in on the extreme low side right about $800k/year in CO2 to operate.
Does this seem right to you all? That seems pretty expensive to run an extraction system daily.
Not sure if my info helps you or not, but here is my dry ice consumption. I run 2 6x36 columns 4 times a day and use 300lbs of dry ice per day give or take a little. And that is for my entire system. I can run 32-35k of fresh frozen in 4 runs. So compared to the amount of product your producing vs dry ice that’s pretty cheap. I only run 2 days a week So it’s not like a large lab running 24/7 but I’m a one man show with a helper from time to time. Power for recovery is also very low . My bill is 60-70$ a month for electricity and I run welders and other tools in the shop also.
The lc02 turns into dry ice in the jacket by the way it’s injected and that’s how it doesn’t cost as much as your calculations. It’s not sent in as a liquid to fill the column.
If you’re spending 60k a year on lc02 for chilling, which would be on the expense side, you would be making an obnoxious amount of hash to justify the consumables.
I tried to make a best effort attempt at getting some data on how much co2 was needed - as a baseline just to fill and chill one column. So after a quick gander at the triple point of co2 its obvious that if I wanted to transfer a liquid and not turn to dry ice it must be over 75psi so I did 100-120psi transfer with the tanks upside-down on a scale. Could watch the cold level rise as the transfer took place. Of the little bit of co2 I had to play with, 40lbs wasn’t enough to fill the column jacket but was instead just under half way.
Once in the jacket I let it depressurize so it would get below -50c by converting to dry ice for a general comparison. I suspect most of the loss was from the depressurization. It only stayed at or below -50c for a short period with a longer lasting -35c to -48c ice block.
Price wise, the cheapest co2 I have ever found is at our local grow shop for $0.375 per lb and everything is calculated from this value based on observed consumption rates. No heat load was applied to the columns in any way, this was simply just to get them to -50c or colder to get a general idea of consumption.
It came in right at about $78k per year per column for co2.
If you have a micro-bulk or micro-cyl that cost will be closer to half that, guaranteed lower than $0.25 per lb. I was paying $.24 in Arizona with a micro-bulk outside, and I could have gotten it cheaper with the micro-cyl (bigger).
When filling the jacket, the other manufacturers aren’t using the liquid phase for cooling. With the needle valve just barely, barely, like rch (red cunt hair, they’re thinner) thin, open the needle valve to “hiss” in the lc02 turning it into a dry ice powder instantly and that’s what’s cooling everything. And why the internal chamber needs to be able to withstand so much pressure. Vessels that are 6" and smaller are capable of having a thicker guage steel. 6" have 6mm thick internal wall and the smaller columns may have thinner as a smaller circumference can withstand more pressure. Nboler uses lc02 on his solvent tanks, which would normally crush them, but he adds support braces on the inside of the tank preventing it from collapsing on itself.
We figured pricing on a bulk cylinder would be much better… what are the install costs like?
Definitely aware of the wall thickness issues… our TCS jackets have the same internal thickness for similar reasons, plus was required for certification.
The initial cool down time though must be pretty long if you are filling it at a rate of rch no?
Would you want to lease the bulk tank or buy it? What size tank would you need based on your consumption? Install costs for a bulk or micro bulk CO2 tank would vary on several factors such as the size of the tank you need, building electricity capability and need for upgrade, concrete pad based on the size of the tank you want, permitting, renting cranes for install, etc. A simple site survey from a supplier like us will help determine all this. Figure out your consumption rate then work backwards. Size of tank, size of concrete pad, needed wattage and possible upgrade, etc. Point is it can add up quickly.
Roughly how much co2 do you typically see consumed by a 6x48 column in an 8hr day of operation?
I would think that after the metal gets cold it wont use as much co2 to maintain temperature. I was un-able to get the entire column below -50c with co2, just the portion with liquid in it. The rest had strange hot/cold spots all over. I assumed this was due to the ice formation inside not being perfectly uniform as would be seen with a liquid.
I suppose filling it differently so that it is full of fine powder dry ice might have the ability to fill the column with less liquid and therefore make it last a bit longer. Will have to try this out on the next round of testing we do.
Hello! I’m trying to double check my napkin math, so if anyone has any input, it’s appreciated!
From my experience, I believe I get 1 lb of butane recovered for 3lbs of dry ice used, but that was a few years ago, and I’ve used recovery pumps since then at my workplace. Unfortunately don’t have my old notebooks
I seem to see some folks indicating more and less, but my search fu is lacking. This was the only post I found that referenced consumption and not recovery rate.
I run 2 6x36 columns 4 times a day and use 300lbs of dry ice per day give or take a little
My napkin math says 160lbs of butane recovered with 300lbs, or roughly ~1.8lbs of dry ice per lb of butane recovered
What do ya’ll think? I think 3:1 is a good estimate, but I’m glad to be proven wrong.
I can chill all 4 6x48 columns all day and not go through a dewar.
It takes about an hour to chill down the solvent, but empty columns are faster.
After playing with co2 for some time now, I think the way you filled it is extremely inefficient…
My columns are insulated so they are still -30 the next morning when I fire up again, so Monday costs more than the rest of the week as it consumes more to chill to -60, I have gotten them to -75c with co2 but that last but takes a while.
Mind you I taught myself how to use the lc02 with dreads advice, so I maybe doing it inefficient also.
I’d say a busy day it would be about 1 dewar for 6 runs, using lc02 for recovery used about 2 dewars for 4 runs.
Dewars are alot more expensive than a microbulk etc, but it’s still worth it considering how much product I can make.
Chiller gets here mid July hopefully so no more lc02 for me.
What is the rating for closed jackets to hold the pressure/conditions of the triple point? I just want to stay safe and I had planned to stay in my 6inch diameter but I question is usalabs steel is rated to hold this method. They don’t know much of anything when it comes to lco2 so I know they’re not accounting for this method.
USA labs steel will not be strong enough. The only two manufacturers that I would recommend to use would be bizzybee and nboler. They are the only ones that have equipment to handle this.
