There was a small article in today’s newspaper about how they’re having a problem in the UK regarding pigs. It seems pigs are slaughtered by suffocation with CO2, but the price of gas (er petrol) is too high, so they stopped doing so. It didn’t say so explicitly, so I assume they burn the fuel to generate the CO2. Now there’s tens of thousands of pigs waiting to be slaughtered.
This makes me wonder: couldn’t they find some other way to get the CO2? Carbon dioxide is already produced by a number of other ways, so wouldn’t it be cheaper to capture it from someone’s smokestack?
From what I can see CO2 used for meat production (specifically stunning pigs before slaughter) is provided by industrial gas supply companies, they get the CO2 primarily as a byproduct generated from ammonia plants. I don’t know if much or any of it is produced by burning gasoline, considering there are a number of processes at industrial scale that generate the gas as a byproduct I have to think those would be preferable to burning gasoline which is itself a somewhat variable priced and always high in demand commodity.
CO2 production in the UK is mainly a by-product of the manufacture of nitrogen-based fertilisers, which is an energy-intensive process.
“Gas prices” in the UK have nothing to do with the price of petrol; the reference is to the price of natural gas, from which much of the UK’s electricity supply is generated. As gas prices have spiked in the UK fertiliser manufacture is currently very expensive, so producers have lowered production and are filling orders from stockpiles accumulated in happier times. They’ll rebuild the stocks back up when gas prices fall.
They just don’t have similar CO2 stockpiles, so they can’t fill orders for CO2. Hence the problem.
Your original question was answered, but your intuition was spot-on here. The reason they capture it from ammonia production is because that’s a process with a high concentration of CO2. Not the ammonia loop itself, but the production of hydrogen from methane and water. More in the wiki link below.
Capturing from SMR is easier than from coal exhaust, which is easier than from natural gas exhaust (combustion for electricity generation, not hydrogen production.)