ABSTRACT

The conversion of CO₂ into fuels and chemicals has emerged as a valuable alternative in the battle to combat climate change, particularly in geographical regions where the subsurface properties are not suitable for CO₂ sequestration. This paper provides a review of various pathways for utilising captured CO₂ to produce synthetic fuels and green chemicals. The pathways are generally agnostic to the source of the CO₂, which mainly affects the purification requirements (such as desulfurisation or deoxygenation). The CO₂ is typically converted into CO, which could be achieved by known chemical processes such as reverse water shift and CO₂ reforming. The CO and H₂ produced from these processes are the building blocks for synthetic liquid products such as methanol, ethanol, jet fuel, diesel, and naphtha. In another variation, the H₂ could be generated from renewable energy sources and electrolysis to produce e-fuels from the captured CO₂. A review of the current and developing technologies and their technology readiness levels is included to determine their suitability for industrial applications, as well as a high-level discussion on factors impacting their economic viability, such as the differences in compression and other energy requirements, process flexibility, and requirements for intermediate storage buffering. The relative cost differences between the various CO₂ utilisation pathways are also presented along with a discussion on suitable cost reduction strategies for each option.