CO2 and CH4 Upcycling to Green Fuels via Non-thermal Plasma

Abstract

Efforts to reduce greenhouse gas emissions such as carbon dioxide (CO2) and methane (CH4) have required effective mitigation technologies. It is an area of deep complexity with numerous techniques proposed and tested to find useful methods of capturing, storing, and utilising CO2 and CH4 in better, cleaner, and greener ways. The task of doing so is further compounded by issues such as organising governmental policies across several nations to address rising emission levels before critical environmental thresholds are reached. Thus, it is becoming clearer that new methods and innovative strategies are required to reduce uncertainty of the world’s future from climate change concerns. This body of work presents studies into an innovative technology known as non-thermal plasma. Plasma is the 4th state of matter that takes the form of ionised gas. This occurs when gaseous matter is excited to the point where atoms become a field-ionised discharge composed of excited species, energetic electrons and charged radicals. These ionised particles have the unique capabilities to create a high-effect mass transfer environment where several different reactions can occur on a micro timescale. This makes it particularly useful for converting normally stable molecules that require large amounts of energy to break bonds and generate a reactive state. Of its many variations, non-thermal plasma (NTP) is a form of plasma that operates at atmospheric conditions. This makes it particularly useful as an innovative form of gas conversion technology. This thesis studies NTP and its use in CO2 and CH4 conversion to develop another form of climate change technology. A novel reactor was developed to create a system that generates NTP in a onestep process. Such a reactor was designed as a quartz tube feeding column that exploited an electrical potential applied from a power supply to generate reactant gases as a spark discharge plasma stream.