Recent advances in high-temperature solid looping processes toward commercial application

Review article, 2026

Over the last ten years, high-temperature solid looping (HTSL) technologies have received considerable interest from industry and academia, with important progress toward commercialization. There are three main HTSL concepts: (i) carbonate looping, based on the reversible carbonation of a metal oxide for separating CO2 from a gas stream; (ii) chemical looping, which utilizes the reversible oxidation and reduction of a metal for separating oxygen from air; and (iii) indirect gasification that uses the sensible heat contained in a hot solid to drive gasification (an endothermic reaction). Different HTSL process variants are used for various CO2 capture applications, such as post-combustion capture, oxyfuel combustion, or pre-combustion capture through gasification and reforming. In this review, we focus on HTSL processes that have reached a high level of maturity, so that commercialization could be expected within the next 5–10 years. This implies that the processes have already been validated in industrially relevant environments, such as pilot testing in continuous operation. Throughout this work, we explain the basic principles of the different HTSL processes and discuss recent advances in arrangements and materials toward reducing costs and energy requirements for CO2 capture from industrial sources. Furthermore, our review provides an overview of existing HTSL pilot plants and the main results from the last 10 years, as well as the latest developments in modeling of HTSL reactors. Lastly, we review the most relevant techno-economic and environmental studies of HTSL processes for various industrial sectors and propose next research steps toward commercial applications in the near future.