The sequestration of CO₂ by conversion to hydrocarbons
thesisposted on 2022-03-28, 17:28 authored by Raha Moossavi Jazari
Carbon dioxide (CO₂) is an abundant greenhouse gas continually emitted into the atmosphere from both natural sources and anthropogenic sources including: fossil fuel combustion, fracking techniques, industrial materials production and land deforestation. Consequently, the natural carbon cycle is overridden leading to strong debates regarding global warming and climate change.The reduction of CO₂ to methane (CH₄), a process known as methanation, has been the subject of extensive study. However most approaches suffer from limitations including: use of sacrificial and expensive metal-based catalysts, high temperature and pressure requirements leading to incomplete reactions, resulting in CO and unreacted CO₂ products. Alternative approaches currently being suggested involve use of silane-based reducing reagents with Lewis acid type catalysts. Consequently this project focused on screening four silane-based reducing agents against B(C₆F₅)₃, a B(C₆F₅)₃/hindered amine tandem catalyst and B(C₆F₅)₃ + tandem catalyst to determine the efficiencies of CH₄ formation and rates of reactions. Additionally, the continuous in situ regeneration of siloxane byproducts into silane reducing agents was investigated. The conversion of CO₂ to CH₄ holds significant potential for the chemical capture of CO₂ and storage of hydrogen in the form of CH₄ which has many applications including: commercial power stations, petrochemical refining and natural gas.