BERC-e 10/12: Capturing carbon from air

At our last BERC Engineers meeting, we discussed Carbon Engineering (http://carbonengineering.com/), a start-up in Canada working to capture CO2 from the air to ultimately produce transportation fuels. They’ve just recently built a pilot plant outside of Vancouver. This pilot plant will produce pure CO2 through a two-step process. The first process uses a contactor to capture CO2 with an alkaline hydroxide capture liquid. A large wall of fans pulls air into the system and pushes the air through corrugated sheets that are coated in the capture liquid, where the CO2 reacts with the capture liquid to form a CO2 rich solution. The second step is to pull the CO2 out of the solution through a regeneration cycle to produce pure, compressed CO2 and to re-use the capture liquid for other cycles. This regeneration cycle is based on a well-known industrial process in which the CO2 rich solution goes through a reaction to form a solid containing the CO2, and the solid is heated to 900 C to decompose the solid and release the pure CO2.

 

Though this might sound great at first, we found many issues with this technology in our discussion. Firstly, it is only half the process needed to actually make fuel. The pure CO2 needs to be combined with hydrogen to form the fuels. Secondly, the system is energy intensive: it requires energy to run the fan systems and requires burning natural gas to generate the 900C heat needed for the process. As one BERC-e member pointed out, 900C heat could be used to directly form fuels from biomass. However, Carbon Engineering does collect the CO2 released from burning the natural gas and plans to use solar power to make the energy economics work. Also, the system is not designed to measurably reduce CO2 in the atmosphere. The most important problem is that the fuel generated will cost $1 per liter when the system is up and running and solar power is used, where currently diesel is just under $1 per liter. All-in-all BERC-e members weren’t too excited about this technology for fuels, but perhaps there is a better use for the CO2 collected.

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