Oxidant-assisted methane pyrolysis.

Area of Science:

• Chemical Engineering
• Catalysis
• Sustainable Energy

Background:

• Methane pyrolysis offers a scalable route to low-CO2 hydrogen production using existing infrastructure.
• Catalyst deactivation and carbon buildup are major hurdles for large-scale methane pyrolysis.

Purpose of the Study:

• To investigate the impact of oxidant addition on methane pyrolysis efficiency and catalyst stability.
• To overcome catalyst deactivation and carbon deposition challenges in methane pyrolysis.

Main Methods:

• Methane pyrolysis experiments were conducted in a fluidized bed reactor at 750 °C.
• Small concentrations of CO2 and H2O were introduced as oxidants with methane over Fe-based catalysts.
• Catalyst performance and effluent composition were analyzed to assess hydrogen and carbon yields.

Main Results:

• Addition of CO2 increased carbon yield twofold and hydrogen concentration 7.5-fold compared to pure methane.
• H2O addition showed similar beneficial effects, preventing catalyst deactivation.
• Evidence suggests a cyclic iron carbide formation and decomposition mechanism enhances methane decomposition and carbon removal.

Conclusions:

• Controlled oxidant addition to methane pyrolysis is a viable strategy to enhance hydrogen and carbon production.
• This method effectively mitigates catalyst deactivation and carbon buildup, improving process economics.
• The findings are applicable to Fe, Ni, and Co-based catalysts, broadening potential industrial implementation.