The Catalyst Review March 2020 - 11

SPECIAL FEATURE
solar energy. The equipment is modular and the largest module-the DAC-36, can capture 5 tons per day (~1,800 tons CO2 per year).
Several modules (either three or six) can be installed together to increase capacity and presumably Climeworks will continue to scale
up its units.
Another company with a DAC process is Carbon Engineering, based out of Calgary, Canada. It has a pilot plant for removing CO2
from the air in Squamish, British Colombia, which employs a liquid-solvent based capture process. The technology is also modular,
consisting of air contactors and a causticizer. CO2 in air reacts with a caustic solution in the contactor to form a soluble carbonate
and is then precipitated out with another alkaline solution in the causticizer. The precipitate is then filtered and heat treated at high
temperatures to release the CO2 as a pure stream (TCGR 2019b). One contactor can capture 100,000 tons CO2 per year. The scale
is more suited to a larger number of utilization products. Carbon Engineering announced that it would begin construction on the
1-million ton per year plant in 2021, with a view to having it operational in 2023. If the company's plans come to fruition, then it
could be able to provide scaled-up units for CCP in the very near future.
The Global Thermostat (GT) process meanwhile relies on technology somewhat like a mix between that of Climeworks and Carbon
Engineering, using an air contactor with a solid amine sorbent. ExxonMobil is investing in GT to scale up the technology for industrial
use (ExxonMobil 2019).
While the main near-term market for CO2 collected at the million-ton scale is enhanced oil recovery (EOR), it could be employed for
a carbon-neutral Smart City, to provide substitute fuel through methanation of CO2 captured locally from DAC units (DAC-CCP). This
could also create a "CO2 Refinery" whereby for each carbon atom combusted in an internal combustion engine or boiler, another is
converted back into fuels and chemical products (Lynch and Watson 2018).
There is regulatory support for DAC-CCP. The new version of the European Renewable Energy Directive (RED II) for instance, does
not support fuels generated from the capture of CO2 from large combustion point sources, but it does allow this for DAC. By
implementing DAC-CCP (and CRU-CCP) we could avoid emission of hundreds of Gt of CO2 into the atmosphere over the next 25 years
and compensate for the CO2 emitted from hard-to-abate sectors. Having access to a method for carbon neutral liquid fuels would
also seem to be a highly pragmatic option and one which does not come with all the difficulties and question marks over the true
ecological and social footprint of biofuels.
CRU-CCP Implementation Strategy
Many industrial micro-emitters are looking for a strategy to abate CO2. This presents several challenges including that there are
so many options to choose from. Not least that the existing business model has to be extended to include that of being a CO2 and
perhaps downstream chemical supplier. Many things come as a surprise to an industrial micro-emitter (IME) when they come to
investigate adding CRU-CCP to their business. The first being the CAPEX. Adding a CO2 recovery unit (CRU) can cost anywhere from
$10-500 million depending on the size of the emissions (Pentair 2019). This could be a higher figure than the value of the existing
plant. In this situation a client might simply decide to build a new generation of plant which lowers or eliminate the emissions,
rather than mitigating them. An example would be in the steel and cement industry if they could move to electric furnaces and
hydrogen. This option is a good one if the cleaner plant technology is available and gives the right product grade. If not CRU-CCP is an
alternative. The more pleasant surprise is that the CO2 sales could rival or even exceed those of the main product. 50,000 tons of CO2
sold for $150/ton for instance, adds another $7.5 million in revenue. Add on an order of magnitude at a larger emitter and an extra
$75 million starts to look very attractive; especially if the capture cost is only $25 per ton. However, there are many factors to be
considered, and hoops to jump through before this dream of making extra money from the world's biggest nuisance can be realized.
One of the first steps to be taken is to speak to a gas recovery company. They will provide a questionnaire that needs to be
completed about IME's plant. These are quite detailed. Table 1 shows some of the information that is typically required from an IME.
Once this information has been obtained, the engineers from the gas recovery specialists visit and inspect the site to understand the
best format for the CRU. Thereafter, gas sampling is required, and over a few months, an independent third-party company takes a
few samples of the flue gas and performs a deep analysis down to parts per billion (ppb) on its composition.
Once all the plant parameters are understood, the final quotation and design for the CRU is provided. While this is ongoing, the
IME needs to make decisions on what to do with the CO2 it captures. As described in the examples above, this could involve one
of four main options: use it captively in the process; sell as CO2 directly to an industrial gas supplier, sell to a company using it in
their application or build an adjacent unit to convert the CO2 into another product. The first three of these options can be realized
relatively quickly. For a CRU to be installed normally takes around 15-18 months from purchase order to operation. The fourth option
The Catalyst Review

March 2020

The Catalyst Review March 2020

Table of Contents for the Digital Edition of The Catalyst Review March 2020