A particle-scale study showing microwave energy can effectively decarbonize process heat in fluidization industry.

Microwave heating converts electromagnetic energy directly into thermal energy within the heated material, thereby overcoming the limitations of traditional indirect heat transfer methods. However, microwaves are well-known to have limited penetration depth, which remains a significant challenge that inhibits the use of microwaves in processes requiring uniform heating. Here, we show that fluidized beds of particles with sufficient electrical conductivity break the limitations imposed by microwave penetration depth, enabling uniform heating in large-scale reactors. Results suggest that the alternating magnetic field penetrates the entire studied reactor to induce eddy currents everywhere, causing each particle to be heated. The power absorption density for Geldart A and B particles across the bed is uniform, with no evidence of exponential attenuation, introducing unexpected penetration depth under the magnetic field component. Utilizing microwave energy, sourced by clean electricity, to heat fluidized beds offers a transformative solution to decarbonize industry, significantly reducing greenhouse gas emissions.