How will this address the public health issues which relate to the burning of fossil fuels? Isn't it just going to make it easier for polluters to pollute more?
Direct air capture: our technology to capture CO₂
41–50 of 168 posts
Re: Direct air capture: our technology to capture CO₂
#42Earlier quoted context omitted.
For context, 4000 tons of CO2 is roughly the emissions of a full 777 flying from San Francisco to London and back twice.
That doesn't sound right, 4000 tons is more than 10 times the maximum takeoff weight of a 777.
It looks about right to me (I used https://www.atmosfair.de/en/offset/flight/)
It’s about 850 US tons per full leg * 4 legs to make up the two round trips
(388 pax in a -300ER)
Re: Direct air capture: our technology to capture CO₂
#43Earlier quoted context omitted.
For context, 4000 tons of CO2 is roughly the emissions of a full 777 flying from San Francisco to London and back twice.
That doesn't sound right, 4000 tons is more than 10 times the maximum takeoff weight of a 777.
Jet fuel is comprised mostly of hydrocarbons with 8 to 16 C atoms, and a large fraction of these hydrocarbons are straight-chain alkanes.
Combustion of dodecane (a C12 straight-chain alkane) makes 12 CO2 molecules. A 747 jet consumes about 4 L of jet fuel per second when in flight. Based on the density and molecular weight of dodecane and the stoichiometry of its combustion reaction, you'd arrive at something like 0.01 ton of CO2 emitted per second of flight time.
4000 tons is a good estimate.
Back of the envelope...
Re: Direct air capture: our technology to capture CO₂
#44Earlier quoted context omitted.
For context, 4000 tons of CO2 is roughly the emissions of a full 777 flying from San Francisco to London and back twice.
That doesn't sound right, 4000 tons is more than 10 times the maximum takeoff weight of a 777.
You have to account for the mass of the oxygen that gets bonded to the carbon in the jet fuel to form CO2. i.e. most of the mass is coming from atmospheric oxygen, not what the aircraft is carrying onboard.
Re: Direct air capture: our technology to capture CO₂
#45Their subscription page is currently offering a rate of about $1.35 USD per kg of CO2 removed, and they promise to complete your order within 6 years. It’s nice to have some hard numbers on end-stage or “gold standard” CO2 offset (no doubt there are cheaper carbon credit options but this directly solves the hardest problem, CO2 that’s diffused into the atmosphere.
For comparison, 1 gallon of gasoline release 9kg of CO2, so it's $0.15 USD more per gallon to be carbon neutral. I think that number is too low to be real.
Re: Direct air capture: our technology to capture CO₂
#46I don't see how these are improvements over algae bioreactors. Capturing the CO2 without reducing it will lead to less oxygen in the atmosphere as well. Also at least with bioreactors you get useful products/energy. This just generates more waste products and consumes energy.
Removing ALL the CO2 in the atmosphere would be 1-2% the partial pressure of O2 in the atmosphere (barometric pressure where you live swings more than that). Of all the concerns, this one’s low on the list.
Re: Direct air capture: our technology to capture CO₂
#47[dead]
Re: Direct air capture: our technology to capture CO₂
#48Explain like I’m 5: Why is this better than just growing trees and then cutting them down and burying them so the co2 never gets back into the atmosphere?
One reason, and not a very compelling one, is that trees in certain latitudes exacerbate global warming by absorbing more heat than naturally occurring grasses (which tend to be more reflective).
In sum, it’s not better.
Re: Direct air capture: our technology to capture CO₂
#49Earlier quoted context omitted.
That doesn't sound right, 4000 tons is more than 10 times the maximum takeoff weight of a 777.
You have to account for the mass of the oxygen that gets bonded to the carbon in the jet fuel to form CO2. i.e. most of the mass is coming from atmospheric oxygen, not what the aircraft is carrying onboard.
TIL, thanks for the explanation.
Re: Direct air capture: our technology to capture CO₂
#50Earlier quoted context omitted.
That doesn't sound right, 4000 tons is more than 10 times the maximum takeoff weight of a 777.
Jet fuel is comprised mostly of hydrocarbons with 8 to 16 C atoms, and a large fraction of these hydrocarbons are straight-chain alkanes. Combustion of dodecane (a C12 straight-chain alkane) makes 12 CO2 molecules. A 747 jet consumes about 4 L of jet fuel per second when in flight. Based on the density and molecular weight of dodecane and the stoichiometry of its combustion reaction, you'd arrive at something like 0.…
Ah, so you're saying (if I'm reading this correctly) that the plane only carries the carbon portion of the CO2, and the oxygen comes from the air itself. That's how it's emitting more CO2 then it's fuel mass.
Is that right?