The catalytic effect of plasma sprayed coatings for improved combustion of gaseous fuels

The article presents methods for reducing CO emissions and other toxic pollutants from combustion processes, emphasising the effect of catalysts to reduce such emissions. One of the most frequently used methods for reducing pollutants is the non-selective reduction of nitrogen oxides, which can be carried out in the presence of catalysts. This method uses CO from carbon-containing fuel combustion to reduce nitrogen oxides. However, this process is much more efficient in the presence of catalysts. The processes of catalytic CO combustion and NOx reduction were carried out in a model chamber by burning natural gas. The results show the catalytic effect of plasma sprayed ceramic coatings on the catalysts and surfaces bounding the combustion spaces on the exhaust gas parameters. The measurements of the natural gas combustion process parameters in the presence of the catalytic coatings showed that the coating based on a mixture of cerium oxide (CeO2) had the greatest reduction effect, and the coating based on the mixture of vanadium oxide (V2O5) had a smaller impact on reducing carbon monoxide amounting to approximately 60%, and a nitrogen oxides reduction rate of 35%. In contrast, the CO reduction rate for the catalysts without the coating was 3%, and the degree of NOx reduction was approximately 6%. The obtained results confirm the desirability of the catalyst coating application for CO combustion and NOx reduction. Catalytic coatings sprayed in multi-layer coating systems can be applied not only on the surfaces of catalysts but also on the surfaces of heating devices, and they may not only have a catalytic effect but can also extend the service life and improve the heating efficiency, which confirms the scope and purposefulness of using the plasma sprayed coatings.