Abstract
The concentration of carbon dioxide (CO2) within the atmosphere reached unprecedented levels mainly due to population and industrial growth, both of them requiring high energy consumption. Strategies such as the use of renewable energy sources, multiple actions aiming to improve the energy efficiency, or the integration of Carbon Capture Utilization and Storage (CCUS) technologies are currently investigated to mitigate the greenhouse emissions. The utilization of CO2 to produce value-added chemical compounds / energy carriers is of major importance to meet the emission targets set by the European Union. The current research is focused on the conversion and valorisation of captured CO2, through CO2 hydrogenation, to produce green C1 high-priced chemicals such as: i) substitute natural gas (SNG), ii) formic acid (FA), and iii) methanol (MeOH). Water electrolysis is considered for H2 production with the employ of renewable energy sources, as for example solar, wind, or hydro power, with the purpose of developing a green and sustainable technology. A thermal output of 100 MW was assumed in the case of SNG production, whilst considering an annual productivity of 10,000 t of formic acid and 50,000 t of methanol. Aspen Plus simulator software was used to model the SNG production, and ChemCAD process simulation software was used for the FA and MeOH production processes. The integrated mass and energy balance data were afterwards used to evaluate all considered cases from a technical perspective. The evaluated designs were validated based on data from the scientific literature. As the results show, the proposed CO2 utilization technologies are very promising in terms of high energy efficiency (50 – 60 % range) as well as high CO2 conversion yields (>90 %).
