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Engineering a Good Scrub

An exciting new pilot project may steer us toward a more carbon neutral future.

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Carbon dioxide, or CO2, is a greenhouse gas that is driving climate change. Emissions from the vehicles we drive include CO2, and this is a significant problem: when CO2 is produced in a factory, it’s relatively easy to scrub emissions clean before being released into the air. The material you see coming out of smoke stacks is actually largely steam.

However, this technology is not practical for small producers like individual cars. And with over 32 million registered vehicles in Canada alone, those small individual amounts start to add up.

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Emissions from point sources like factories are easy to scrub clean. The gas you see exiting smoke stacks is actually largely steam.

Calgary-based company Carbon Engineering wants to apply smoke stack scrubbing technology to CO2 present in atmospheric air, and has shown that their air contactors can remove 80% of the CO2 that they draw in.

As a pilot, Carbon Engineering has built an array of air contractors in Squamish, BC, between Vancouver and Whistler. Set to start operating this year, the pilot plant will clean 500 tons of CO2 out of the air, which is about the average annual CO2 emission from 125 cars. And that’s just the start: if the pilot is successful, a full commercial array could be set up as early as next year, processing a million tons of CO2 each year.

Check out this video from Carbon Engineering to see the technology in action, and learn more about how it works.

Carbon Engineering’s air contactors pull in atmospheric air and extract CO2 by contact with an absorbent liquid

Briefly, by borrowing from tried and true industrial scrubbing technology, these air contactor units bring atmospheric air in contact with a CO2-absorbing liquid. The geometry inside the air contactors is designed to maximize contact between the two, capturing up to 80% of the incoming CO2 in the liquid phase as carbonate. Once processed, the CO2 and clean absorbing fluid are both recovered separately, and the purified CO2 can be used for any number of commercial applications, including adding fizz to your summer drink.

Perhaps even more exciting is the eventual prospect of making fuel out of your exhaust. The purified CO2 , when reacted with hydrogen, can be converted into a low carbon fuel. The resulting synthetic diesel could be used to power local buses. This fuel, made from the air instead of being drawn from the ground, would be carbon neutral.

Critics, however, are quick to point out that direct air carbon capture is only one part of the tools we need to curb climate change. Computer simulations of the impact of removing CO2 from the air would be slow. CO2 that makes it into the air gets locked deep in our oceans as acid, meaning that removing CO2 from the air at some later time is not the same as reducing our emissions altogether. Removing 25 million tons of CO2 from the air each year would only restore the surface pH of our oceans to normal levels by 2030.

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Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.