Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Academic Visitor



thomas.hills07 Website CV




Bone BuildingSouth Kensington Campus





I am an Academic Visitor in the Department of Chemical Engineering at Imperial College London, collaborating on several research projects such as LEILAC, a €21M, 5-year Horizon 2020 project, and ASCENT.

I currently work for Calix, a company developing materials to solve global challenges through new solids processing technologies. Currently, Calix produces nano-active MgO which is used in wastewater treatment, sewer corrosion protection, water conditioning and fertilisers. We are rapidly expanding into other industrial sectors such as low-carbon cement and lime manufacture via the LEILAC project.

My areas of expertise are the policies and technologies required to decarbonise industrial processes, with a particular focus on carbon capture and storage (CCS). I have published several papers on the topic, as well as contributing to various projects with Imperial Consultants.

I graduated with a PhD from Imperial College in August 2016 on the topic of carbon capture in the cement industry (see below). I was funded by the Grantham Institute, Climate-KIC and Cemex Research Group AG. Before this, I received a First Class Masters of Engineering (Hons) in Chemical and Nuclear Engineering from Imperial College in 2011.

I took a break from my PhD in 2013 to work at the Grantham Institute - Climate Change and the Environment to work as a Research Assistant on industrial decarbonisation policy. This role led to presentation of results at a European energy efficiency conference.

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Phd research

My PhD research centered around two main topics: the quantification of CO2 uptake by concrete over its lifetime, and the detemrination of the suitability of the  calcium looping CO2 capture process with cement manufacture. My supervisors were Prof Paul Fennell and Dr Nick Florin.

Absorption of CO2 by concrete

Limestone (calcium carbonate) is the main feedstock for cement production; cement is used to make concrete (mainly calcium hydroxide), which absorbs COfrom the atmosphere over time, reverting to calcium carbonate. The determination of this rate is of great importance: millions of tonnes of CO2 are absorbed every year. I undertook an exhaustive review of the data in the literature and has applied statistical methods to estimate the rate at which the absorption happens. I then coupled this rate with cement production and used data to estimate the amount of CO2 absorbed by all the concrete in the world, over a 125-year period.

Integrating cement manufacture and calcium looping CCS

Post-combustion carbon capture processes remove CO2 from the gases emanating from the combustion of fuels in air. Calcium looping (CaL) is one such process, but has a major drawback: the calcium oxide (CaO) sorbent which separates the CO2 from the flue gas loses its CO2 carrying capacity over time and so must be removed and replaced by fresh limestone. This produces a waste stream of low surface-area, ‘spent’ calcium oxide. Calcium looping becomes more financially viable if this waste stream can be used as a feedstock in cement manufacture, especially if the calcium looping process captures the cement plant's CO2 in the first place. Therefore, the validation of this coupling of CO2 capture and cement production is imperative. I investigated the effects on the performance of cement made with this ‘spent’ calcium oxide.



Hills T, 2016, Highlights from Carbon Capture and Storage: Faraday Discussion, Sheffield, UK, July 2016, Chemical Communications, Vol:52, ISSN:1359-7345, Pages:13323-13326

Lee JM, Rochelle G, Styring P, et al., 2016, CCS - A technology for now: general discussion., Faraday Discuss, Vol:192, ISSN:1359-6640, Pages:125-151

Smit B, Graham R, Styring P, et al., 2016, CCS - A technology for the future: general discussion, Faraday Discussions, Vol:192, ISSN:1359-6640, Pages:303-335


Hodgson P, Sceats M, Majumder K, et al., 2018, Nano-active electrode materials, Pages:373-374

Hills TP, Sceats M, Rennie D, et al., 2017, LEILAC: Low cost CO2 capture for the cement and lime industries, 13th International Conference on Greenhouse Gas Control Technologies (GHGT), Elsevier, Pages:6166-6170, ISSN:1876-6102

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