Flue Gas Reforming of Methane Over a Ni-Al2O3 Catalyst: A Microkinetic Modeling and Experimental Study

Flue gas reforming of methane (FGRM), which involves the cofeeding of methane to an existing industrial flue gas stream, is an effective route to convert flue gas into syngas. Here, we perform the FGRM reaction over a freshly prepared Ni/gamma-Al2O3 catalyst and simultaneously develop a microkinetic model using an existing methane reforming reaction mechanism applicable for the Ni catalyst. Experiments and simulations are carried out using methane and synthetic flue gas from coal-fired or natural gas-fired burners over a range of contact times (0.04-0.33 g(cat) h/g mol(reactants)) and temperatures (600-700 degrees C). The parity plots reveal that the model can closely predict the experimentally observed values (R-2 >= 97). With an increase in contact time, the conversion of reactants (CH4, CO2, and H2O) and yield of products (H-2 and CO) gradually increase, whereas the H-2/CO molar ratio rapidly decreases and approaches a constant value at high contact times. Moreover, conversions and yields also increase with an increase in the reaction temperature. The experimental and simulation data show that the excess water in flue gas from natural gas-fired burners results in lower CO2 conversions and higher H-2/CO ratios. However, the CH4 conversion and H-2 and CO yields remained unaffected. No evidence of coke deposition is seen on the spent catalyst surface, even at low contact times and a reaction temperature of 600 degrees C. To further explain the trends observed during the FGRM reaction, the variation of surface species coverage with contact time and temperature is also examined.

Automated summary

Flue gas reforming of methane is an effective method to convert industrial flue gas into syngas. The conversion of reactants and yield of products increase with higher contact time and temperature. Additionally, the water content in flue gas from natural gas-fired burners affects the CO2 conversion and H-2/CO ratio.