Sister blog of Physicists of the Caribbean in which I babble about non-astronomy stuff, because everyone needs a hobby

Wednesday, 3 April 2019

Turning air into oil

A technology that removes carbon dioxide from the air has received significant backing from major fossil fuel companies. British Columbia-based Carbon Engineering has shown that it can extract CO2 in a cost-effective way. It has now been boosted by $68m in new investment from Chevron, Occidental and coal giant BHP.

Carbon Engineering says that its direct air capture (DAC) process is now able to capture the gas for under $100 a tonne. With their new funding, the company plans to build its first commercial facilities. These industrial-scale DAC plants could capture up to one million tonnes of CO2 from the air each year.

Carbon Engineering's barn-sized installation has a large fan in the middle of the roof which draws in air from the atmosphere. It then comes into contact with a hydroxide-based chemical solution. Certain hydroxides react with carbon dioxide, reversibly binding to the CO2 molecule. When the CO2 in the air reacts with the liquid, it forms a carbonate mixture. That is then treated with a slurry of calcium hydroxide to change it into solid form; the slurry helps form tiny pellets of calcium carbonate. The chalky calcium carbonate pellets are then treated at a high temperature of about 900C, with the pellets decomposing into a CO2 stream and calcium oxide. That stream of pure CO2 is cleaned up to remove water impurities.

The captured CO2 is mixed with hydrogen that's made from water and green electricity. It's then passed over a catalyst at 900C to form carbon monoxide. Adding in more hydrogen to the carbon monoxide turns it into what's called synthesis gas. Finally a Fischer-Tropsch process turns this gas into a synthetic crude oil. Carbon Engineering says the liquid can be used in a variety of engines without modification.

"The fuel that we make has no sulphur in it, it has these nice linear chains which means it burns cleaner than traditional fuel," said Dr McCahill. "It's nice and clear and ready to be used in a truck, car or jet."

I'd have to wonder about just how clean this is, but I don't agree with the concerns about this being used to allow more fossil fuels or that reducing energy consumption is in and of itself somehow a good thing. Carbon sequestering is something that ought to be encouraged. Humans have already caused enough damage to the planet and have a responsibility to clean up after themselves. It's like waking up hungover in someone else's house and realised you've made a horrible, horrible mess : do you just run away or do you, in a ghastly fit of sobriety, at least offer to help them clean up ? Of course if you do find you're actually not as sober as you thought, then you stop, make your apologies, and leave them the hell alone, but to not make the initial offer is just really rude. So we should absolutely try for all clean forms of power. If this is carbon neutral, or better yet carbon negative, then I see no reason whatsoever to avoid it.

Climate change 'magic bullet' gets boost

British Columbia-based Carbon Engineering has shown that it can extract CO2 in a cost-effective way. It has now been boosted by $68m in new investment from Chevron, Occidental and coal giant BHP. But climate campaigners are worried that the technology will be used to extract even more oil.

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