Trace Methane Destruction within the Effluent of Microwave Plasma

Area of Science:

• Environmental Science
• Plasma Physics
• Chemical Engineering

Background:

• Atmospheric methane concentrations have significantly increased since preindustrial times, exacerbating the global climate crisis.
• Methane emissions from agriculture, particularly from livestock, contribute substantially to this increase.

Purpose of the Study:

• To investigate the efficacy of microwave plasma for destroying trace methane concentrations, simulating conditions found in agricultural settings like cow barns.
• To explore the potential for converting methane into valuable products or less harmful substances like carbon dioxide.
• To assess the energy efficiency of plasma-based methane destruction compared to existing methods.

Main Methods:

• Experimental setup using microwave plasma to treat methane-containing air.
• Evaluation of various gases within the plasma and downstream methane injection.
• Utilizing Fourier transform infrared spectroscopy (FTIR) to measure methane and other IR-active product concentrations in the reactor effluent.

Main Results:

• No tested gas combination achieved lower energy costs than current methane removal methods, though oxygen showed potential for comparable efficiency.
• Simultaneous destruction of trace methane and production of nitrogen oxides (NOx) was achieved with an energy cost of 3 MJ/mol-(NOx).

Conclusions:

• Microwave plasma technology can effectively destroy atmospheric methane.
• The process offers a dual benefit for agriculture: simultaneous methane emission reduction and sustainable production of nitrate fertilizers from NOx fixation.