(617g) Effect of Alumina On Oxidative Steam Reforming of Ethanol for Minimization of CO Formation and Maximization of H2 Selectivity | AIChE

(617g) Effect of Alumina On Oxidative Steam Reforming of Ethanol for Minimization of CO Formation and Maximization of H2 Selectivity

Authors 

Pant, K. K., Indian Institute of Technology, Delhi



As conventional fuels deplete rapidly, reforming of hydrocarbon feedstocks for hydrogen generation and production of clean energy gains huge importance. Ethanol is a potentially good feedstock for reforming because of its non toxicity and free availability. Therefore developing a new cheap, stable catalyst for H2 yield maximization and CO minimization during reforming at optimum conditions is of core importance.

The study of oxidative steam reforming of ethanol was performed using Ni/Al2O3-CeO2-ZrO2 and Ni/CeO2-ZrO2 catalyst to investigate the hydrogen production in a micro-reformer. The catalysts were prepared by oxidative co-precipitation followed by wet impregnation method and were characterized using Temperature Programmed Reduction (TPR), X-Ray Diffraction (XRD), and Energy dispersive X-ray (EDX) and BET surface area analysis. BET surface area analysis showed multifold increase in pore volume and area for alumina based catalysts as compared to the other catalyst. Various kinetic parameters like time on stream, temperature, pressure, oxygen/ethanol and ethanol/steam ratios were studied. Effects of addition of alumina and reforming temperature were studied for hydrogen production at water/ethanol/oxygen ratio of 9:1:0.35 in a temperature range of 550° C to 750 ° C. Operating parameters were predicted from thermodynamic studies done prior to the experimental analysis. Effect of contact time was also studied by performing experiments with W/FA0 ranging from 3.4 to 13.8 kgcat.h/kgmol[ethanol]. Selectivity trends of H2, CO, CO2 and CH4 were close to the predicted values attained by thermodynamic analysis. As the reforming temperature increases extent of methanation, methane dry reforming and water gas shift reaction decreases leading to increase in CO selectivity and reduction in CO2 and CH4 selectivity. Effect of temperature on conversion and yield for both the catalysts was studied and a comparison based on H2 selectivity, yield and CO selectivity revealed that alumina based catalyst is better in terms of its stability and its performance. Results showed that hydrogen selectivity and conversion for alumina based catalyst was higher where as methane and CO selectivity was lower relatively. Significant yield of H2 corresponding to (74%) 3.66 moles (out of 4.9-thermodynamic maximum) per mol of ethanol and selectivity (67%) was obtained at optimal conditions for Ni/Al2O­­3-CeO2-ZrO2 catalyst.