Improving pollutant emission performances of natural gas combustion in a metal fiber surface burner using Y2O3-BaO-ZrO2 catalytic coatings

This study investigates the combustion and emission performances of low-environmental-impact premixed metal fiber burners for natural gas combustion. High-temperature resistant Y2O3-BaO-ZrO2 was developed through solid state synthesis (SSS) and solution combustion synthesis (SCS), followed by deposition onto Fe-Cr-Al alloy metal fiber matrices. The investigation encompassed various combustion powers (P), excess air ratios (λ), and loading amounts (fcat), within this heterogeneous combustion system. Results demonstrated that while different Y2O3-BaO-ZrO2 coatings exhibited minimal impact on the flame behavior in different combustion models, a significant 30 % average increase in near-surface burning temperature was observed at high P with λ = 1.20–1.30. CO emissions decreased monotonically with increasing λ before reaching stabilization, whereas NO emissions displayed an initial increase followed by subsequent reduction. At relative low P, catalytic burners effectively reduced both CO and NO emissions across a broad λ range, particularly for SCS-coated fibers. However, under high λ and elevated P conditions, both coatings led to a significant increase in thermal NO emissions due to combustion strengthen. Notably, an optimal fcat of 1 % achieved an average reduction of over 50 % in both CO and NO emissions throughout the testing range, providing an innovative green and sustainable pathway toward ultra-low pollutant emissions.