Hello all,
We are in the process of spec'ing a N2 generator for our facility to replace an 850lbs trailer mounted bulk tank. Our current set up was only meant to be a temporary solution when we worked through a lengthy CO2 allocation starting last spring but are happy with N2 gas in the plant. We know it is very inefficient to store bulk N2 due to venting loss. I would like to estimate how much N2 is lost due to off-gas/venting in storage to better understand the generator ROI. I know this can be significant (especially in our scenario) but I can't find a good resource providing an estimate. I found one article stating "this process is called off-gassing and can consume upwards of 20% of your bought supply." However, I don't know at what usage rate or idle time point that is based off of.
- We use N2 at our can line and need to top up the bulk tank (600-800lbs) 1x/week
- We only can 3 days/week for 9-11h/day and the tank is idle the remaining days.
- Flow during canning runs is ~400L/min at 30psi for the duration of the run.
- Ambient temp ranges from 32°F (0°C) in winter to 100°F (38°C) in summer (not sure how much this matters since the boiling point of N2 is -320°F (-195°C).
I have calculated the ROI of the generator based on our N2 consumption in the plant relative to the compressed air cost to feed the generator but assume its even better since we won't have storage losses. I don't need to calculate an exact number but a good baseline of how much N2 we purchase never makes it into the building would be great. If that 20% number makes sense, then great.
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Campbell Morrissy, PhD
Director of Brewery Operations
pFriem Family Brewers
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