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Canadian Company Gets $68M Investment To Turn CO2 Into Fuel (bbc.com)
An anonymous reader quotes the BBC:
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... With its new funding, the company plans to build its first commercial facilities. These industrial-scale direct air capture (DAC) plants could capture up to one million tonnes of CO2 from the air each year....
Carbon Engineering's process is all about sucking in air and exposing it to a chemical solution that concentrates the CO2. Further refinements mean the gas can be purified into a form that can be stored or utilised as a liquid fuel.... 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 Carbon Engineering's Dr Jenny McCahill. "It's nice and clear and ready to be used in a truck, car or jet."
CO2 can also be used to flush out the last remaining deposits of oil in wells that are past their prime. The oil industry in the US has been using the gas in this way for decades. It's estimated that using CO2 can deliver an extra 30% of crude from oilfields with the added benefit that the gas is then sequestered permanently in the ground... There is a big worry that with large investments from the fossil fuel industry, the focus of Carbon Engineering's efforts could be turned to producing more oil, not just tackling climate change. Carbon Engineering says that if governments want to invest in its process they are very welcome to do so. If they're not ready to stump up the cash, the company is happy to take funding from the energy industry as time is so short, and the need for the technology is so great.
Carbon Engineering's process is all about sucking in air and exposing it to a chemical solution that concentrates the CO2. Further refinements mean the gas can be purified into a form that can be stored or utilised as a liquid fuel.... 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 Carbon Engineering's Dr Jenny McCahill. "It's nice and clear and ready to be used in a truck, car or jet."
CO2 can also be used to flush out the last remaining deposits of oil in wells that are past their prime. The oil industry in the US has been using the gas in this way for decades. It's estimated that using CO2 can deliver an extra 30% of crude from oilfields with the added benefit that the gas is then sequestered permanently in the ground... There is a big worry that with large investments from the fossil fuel industry, the focus of Carbon Engineering's efforts could be turned to producing more oil, not just tackling climate change. Carbon Engineering says that if governments want to invest in its process they are very welcome to do so. If they're not ready to stump up the cash, the company is happy to take funding from the energy industry as time is so short, and the need for the technology is so great.
This doesn't make much sense to me. So in the little flow chart between sequestration and pumping it back into a hey as fuel, there is a 'fuel synthesis step' that is going to be an energy intensive step since you can't really burn CO2 to get energy as it is the product is combustion. Thermodynamically you're going to need to put a shit ton of energy in to resynthesize the long chain carbon bonds so you can burn it as fuel. So unless your energy input is clean this will not work well at any scale.
The article does not deign to actually explain the capture process completely or with reasonable accuracy, nor discuss whether the whole "fuel making" claim is really relevant to carbon capture.
There are two cycles involved in the capture process, potassium hydroxide dissolved in water (aka "hydroxide-based chemical solution") captures CO2 from air bubbled through it, forming potassium carbonate (chemistry labs everywhere use this reaction to scrub CO2 from air going to reactions where this is a problem). Then the K2CO3 solution is mixed with calcium hydroxide and it is cooked in a pellet reactor to convert the K2CO3 back to KOH, while converting the Ca(OH)2 to CaCO3 (calcium carbonate, aka chalk or limestone). The second cycle heats the CaCO3 in a furnace to convert it to calcium oxide (CaO), releasing CO2. This is also the first step in making cement.
Carbon Engineering then proposes they will make synthetic fuel with a whole bunch of other chemistry, requiring a cheap source of energy that produces hydrogen gas (Carbon Engineering's on-line papers suggest electrolysis using solar power, the BBC article just assumes it exists).
Here is the thing. The cement industry already produces huge amounts of CO2 from roasting limestone to make cement (8% of world CO2 release is from this source). These are large fixed plants, that already are concentrated sources of CO2, which is free - it is currently just dumped in the air. If you want to make synthetic fuel, why not just build the Fischer-Tropsch plant, and the hydrogen source, next to cement plants and avoid the extra cost and complexity and energy use of extracting it from the very dilute form of air?
Given the vast source of concentrated free CO2 being dumped from cement plants, this "carbon capture" scheme makes no sense at all, if we don't first capture that really easy to get concentrated CO2 from cement. I suggest that this is not really a serious project, aimed at doing anything useful, but a scheme to divert attention from stopping existing CO2 emissions ("We''ll just capture it later and make more fuel! Win, win!").
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