Preparation and eva‎luation of nickel nanostructured catalysts in acetic acid steam reforming for hydrogen production

1/1/1900 12:00:00 AM

The presence of hydrogen-carrying compounds in abundance in nature make hydrogen a great source of energy for future energy needs. Abundant biomass is one of the promising sources of hydrogen production. This not only solves the problems of agricultural waste disposal but also reduces our dependence on fossil fuels for the energy we need. Biomass-derived bio-oils can be an efficient way to produce hydrogen. Acetic acid is a major component of bio-oils and has been widely studied by researchers around the world as one of the components of the bio-oil test for hydrogen production. Hydrogen can be produced by acetic acid using a catalytic steam reforming process that is thermodynamically feasible and has been investigated. Among the catalysts used in this reaction, the nickel-based alumina catalysts have been considered as potential catalysts due to the acceptable price and catalytic performance. In this study, the effect of nickel loading (5, 7.5, 10, 12.5, 15, 17.5, and 20 wt.%) on the catalytic performance of Ni-Al2O3 catalyst prepared by a new and simple mechanochemical method was investigated. The results showed that the mechanochemical synthesis was effective for the fabrication of Ni-Al2O3 catalysts and these samples had a specific surface area of 185-215 m2/g. The catalyst with 17.5% nickel has a conversion rate of 99% and a hydrogen yield of 70% for maximum hydrogen production at 350 to 600 ° C and this catalyst was selected as the optimal catalyst. Considering the formation of carbon in this process and its role in deactivating the catalyst, the effect of adding different promoters to reduce the amount of carbon formation on the catalyst and increase its stability using Mg, K, Cr, and Ce compounds was studied. Among these promoters, potassium showed a more significant decrease in carbon formation and increased catalyst stability and based on these results it was selected as a suitable promoter in this research. The effect of adding different percentages of potassium (1, 3, and 5wt.%) was also investigated. Among the eva‎luated values, the catalyst with 3% potassium content had a high acetic acid conversion rate of about 95.9%, with high stability during 6 hours, and less carbon formation than the sample without promoter. Also, the effect of calcination temperature, steam-to-feed ratio, gas space velocity (GHSV), and reduction temperature were investigated for two optimal catalysts. In addition, the chemical and physical properties of the prepared catalysts were eva‎luated using various analyzes including XRD, BET, TPR, FESEM and, TPO.

ريفرمينگ كاتاليستي , استيك اسيد , توليد هيدروژن , سنتز مكانيكي-شيميايي , ريفرمينگ با بخارآب , كاتاليست¬هاي نانوساختار نيكل

Catalytic reforming , acetic acid , hydrogen production , mechanical-chemical synthesis , steam reforming , nickel nanostructured catalysts

Amir Ghorbani

Dr. Mehran Rezaei - Dr. Seyed Mehdi Alavi