Conversion of Carbon Dioxide to Fuel, Feed and High Value Chemicals

Carbon capture and utilization (CCU) technologies propose the valorization of carbon dioxide (CO₂) after capture, labelling CO₂ as a resource. The advantages of CCU are multifold, which include a reduction in greenhouse gas (GHG) emissions, a decreased dependence on petroleum-based products, storing renewable energy, creating green jobs and establishing a circular carbon economy. This chapter provides an overview of the CO₂-derived product, the basics of existing conversion technologies, and also assesses the economic viability and environmental impact of CO₂ conversion routes. Due to the thermodynamic stability of CO₂ molecules, valorization process demands energy, which can again lead to CO₂ emissions. Hence, it becomes important to assess the potential conversion routes, which will require lower energy, simultaneously generate a product that has significant market value and utilize more CO₂ than the emission during the process. In this regard, potential CO₂-derived products and conversion technologies are solid carbonates by mineral carbonization, fine chemicals and plastics by polymerization and copolymerization, biodiesel from algal cultivation, and methanol from electrochemical reduction. For catalytic reduction and hydrogenation, there lies a need for developing inexpensive, robust and regenerable catalysts, and an improvised design of reactors is required to accommodate catalyst adsorption–regeneration steps to proceed toward commercial installations. CO₂-based fuels could be superior to current fossil fuels when CCU is powered by renewable energy. In the future, for each CCU technology investigation, life cycle assessment (LCA) and scrutiny of CCU as negative emission technology (CCUNET) must be laid out. The field of CO₂ valorization for value addition, simultaneously mitigating climate change is advancing and demanding further investigations and implementation approaches to be in accordance, globally.