Nanotubes from waste CO2

In the sixth article about the companies short-listed within the Global Cement & Concrete Association’s Innovandi Open Challenge, Global Cement speaks with The Cool Corporation’s Josephine Tyler...

Global Cement (GC): Please could you outline The Cool Corporation’s technology?

Josephine Tyler (JT): Our technology converts CO₂ into high-performance solid carbon materials, specifically nanotubes. Not only are these a high value product, but they are extremely inert, resulting in permanent carbon storage. The nanotubes can be used as additives in cement and concrete, enhancing the mechanical, and thermal properties of the built environment, while simultaneously offsetting, or even eradicating, the CO₂ footprint!

GC: How does it work?

JT: CO2 and hydrogen (H2) are mixed in a carrier gas, usually nitrogen (N2­­). The mixture is passed over a metal catalyst at ~200°C and moderately elevated pressure. This generates multi-walled carbon nanotubes, along with some waste gases - mainly unreacted CO₂ and H₂, carbon monoxide (CO), short-chain hydrocarbons and water vapour. Many of these can be recylced back into the process.

This approach differs from other nanotube production processes, which predominantly use fossil-fuel based feedstocks, be it methane, ethylene or alcohols. This is the key environmental benefit of our approach. Another benefit is that - fully commercialised - our process would flip the economics of CO₂ capture on its head. Conventional CO₂ capture, whether it uses amines, membranes, mineralisation or other approaches, represents little more than a cost
centre at present, with minimal revenue generated. In contrast, our process manufactures a high-value additive. And it’s not just cement and concrete that can use nanotubes, there’s a whole range of applications for them, from batteries to polymers, aerospace materials, sports equipment and more.

GC: By how much does your technology reduce the embodied CO₂ emissions of concrete?

JT: Using CO₂-derived nanotubes made from cement plant flue gas will reduce the embodied emissions of placed concrete by 30 - 100% compared to conventional approaches. The exact amount depends on the dose of carbon nanotubes within the matrix, the emissions-intensity of the energy used, and the composition of the cement.

Incorporating carbon nanotubes into concrete also offers further environmental benefits by enhancing the durability of concrete, leading to longer-lasting structures. This allows for thinner, more resource-efficient designs.

GC: You mentioned some other properties that nanotubes impart to concrete in your first answer. Can you expand on these?

JT: Carbon nanotubes are highly thermally conductive, which may help concrete - and thus buildings - regulate temperature. This property could be very beneficial in a warming world. There’s also a lot of evidence that nanotubes can prevent crack propogation in concrete, as they help to bridge cracks before they can grow.

GC: At what scale are you currently operating?

JT: We are still in the laboratory at the moment but are actively developing the next step, which will be an industrial pilot in a relevant setting. We have the designs set out, but we need to carefully assess a number of parameters to identify the optimum site.

As we grow, we will also have to consider raw material supplies. At the moment our H2 is from commercial suppliers. In the longer term, our process would need to source sufficient quantities of renewably-generated hydrogen to be realised at scale. We are all set on the CO₂ side, as there are lots of industrial sources that we could use.

GC: Does that mean that cement and concrete are just one option among many?

JT: We are somewhat agnostic about both where the CO₂ comes from and where the nanotubes are used. We could deploy the technology at a cement plant, a steel plant or a direct air capture (DAC) plant. However, cement and concrete both generate CO₂ and can benefit from nanotubes. These sectors present us with a win-win scenario!

We have had productive discussions with several players in the cement sector already, which has provided a lot of useful feedback. Of course, we are having this discussion today because The Cool Corporation has been short-listed as part of the GCCA’s Innovandi Open Challenge. While I cannot reveal too much, we are continuing with this process.

GC: There are some considerable health and safety considerations around nanotubes. How would these be mitigated in a cement plant?

JT: Nanotubes are hazardous to human health and to the wider environment, predominantly due to their high aspect ratio. Due to this, they should be stored carefully, ideally by dispersion in an appropriate solvent soon after manufacture. They can then be added to cement and concrete blends at the required dosage. Our industrial vision is to supply and operate the nanotube plants using a service contract model, so the cement producer will not need to be involved in these often difficult operations.

GC: How much of an impact do you think your technology will have by 2030?

JT: By 2030, The Cool Corporation wants to abate hundreds of thousands of tonnes of CO₂ every year, aiming for the Gigatonne scale by 2050. We first want to focus on the markets of Europe and North America. These regions are best developed in terms of existing CO₂-capture installations and are open to novel cement blends such as those that will be made using our technology. They present the best initial options for The Cool Corporation.

GC: Thank you for your time today Josephine. We look forward to following the company’s progress.

JT: You are very welcome!