Experimental Studies on Iron-Based Catalytic Combustion of Natural Gas
Catalytic combustion is an efficient method to reduce pollutant emissions produced by a variety of fuels. In this thesis, the use of iron pentacarbonyl (Fe(CO)5) as a catalyst precursor in the combustion of natural gas is experimentally studied. The counter-flow diffusion flame burner is employed as the experimental apparatus. The products of combustion are analyzed by using a Gas Chromatograph (GC) to quantitate the effects of adding the catalyst. The experimental setup is such that a mixture of methane (CH4) and nitrogen (N2) is fed from the bottom burner while a mixture of oxygen (O2) and air is supplied from the top burner. The combustion of natural gas without catalyst is first characterized. The oxidizer and fuel flow parameters are set up so that a stable, flat blue flame is formed close to the centre plane between the two burners upon ignition. The experimental results agree with the literature data and the numerical predictions from CHEMKIN software. To investigate and evaluate the performance of iron-containing catalysts on emission reduction, a small amount of separated nitrogen flow is used to carry iron pentacarbonyl into the flame through the central port of the fuel-side burner. Catalytic combustion produces an orange flame. Compared with the non-catalytic combustion data, it is found that carbon monoxide (CO) and soot precursor acetylene (C2H2) are reduced by 80% to 95% when 7453ppm iron pentacarbonyl is added.