Chemical looping combustion in a rotating bed reactor--finding optimal process conditions for prototype reactor

Area of Science:

• Chemical Engineering
• Combustion Science
• Materials Science

Background:

• Chemical looping combustion (CLC) offers a promising pathway for efficient combustion and carbon capture.
• Rotating bed reactors present a novel configuration for CLC, potentially enhancing gas-solid contact and process control.

Purpose of the Study:

• To design, construct, and test a lab-scale rotating bed reactor for chemical looping combustion.
• To investigate the impact of process parameters on reactor performance, including methane conversion and CO2 capture efficiency.
• To assess the operational stability and identify limitations of the prototype reactor.

Main Methods:

• A rotating bed reactor was fabricated using a CuO/Al(2)O(3) oxygen carrier and methane fuel.
• Key parameters like bed rotation frequency, gas flow rates, and reactor temperature were systematically varied.
• Performance was evaluated based on methane conversion, CO2 capture efficiency, and CO2 purity.

Main Results:

• Achieved approximately 90% methane conversion and over 90% CO2 capture efficiency (based on converted methane).
• Demonstrated stable reactor operation for several hours, with the ability to recover from unstable conditions.
• Observed CO2 purity ranging from 30% to 65%, primarily limited by air slippage.

Conclusions:

• The lab-scale rotating bed reactor shows significant potential for chemical looping combustion with high conversion and capture rates.
• Air slippage is identified as the main drawback, impacting CO2 purity in the current prototype design.
• Future iterations and up-scaling are expected to mitigate gas mixing and improve overall reactor performance.