State-Of-The-Art Overview of CO2 Conversions

Due to the environmental problems about climate change and global warming, carbon dioxide is transformed and valorized from an emission to a raw material of many chemical production processes. This contributes transforming the linear economy into a circular one, considering the principles of reduction, reuse, recovery, recycle. However, the potential carbon dioxide uptake is lower compared to the worldwide CO2 emissions, estimated of 37 Gt actually. In the literature, many utilization options are suggested and are evaluated according to the 3E performance criteria (engineering–economic–environmental), including nine key indicators. An economic estimation and an analysis about the market size of the main carbon dioxide-based products are here suggested. Moreover, with particular attention, in this work, different routes for carbon dioxide utilization are reviewed: chemicals, fuels, concrete building materials, horticulture and microalgae production as well as mineral carbonation, oil and methane recovery and some direct uses. Cycling, closed and open pathways can be realized. Carbon dioxide utilization pathways ensuring a promising development in the next years are suggested.