Preparation and eva‎luation of Yttria Promotted Nickel-based Catalysts in Dry Reforming of Methane

1/1/1900 12:00:00 AM

Over the past few decades, many problems in the field of energy supply needed by industries and factories, such as the limited resources of fossil fuels and environmental problems, have forced scientists to find new sources and methods of energy production. A new alternative to fossil fuels is hydrogen, which can be produced in a variety of ways. Catalytic reforming of hydrocarbons is one of the most common methods of hydrogen production used in the chemical industry. Of the various types of reforming, dry reforming of methane uses two greenhouse gases methane and carbon dioxide to produce synthesis gas with an equal ratio of hydrogen to carbon monoxide. In this research, yttrium oxide (Y2O3) promoted Ni/Al2O3 catalysts have been used to produce syngas in dry reforming of methane process. In the first part of the research, the alumina and yttria promoted alumina supports were synthesized by mechano-chemical method and then the nickel active phase was loaded on these supports by incipient impregnation method with 10 wt%. After conducting characterisitc analysis and activiy tests, the 10Ni/15Y2O3- Al2O3 sample with specific surface area of 164.52 m2/gr and conversion of 76.5% and 78.8% for methane and carbon dioxide at 700 °C was selected for continiuation of research. In the next step, the effect of different nickel loadings was investigated. The results showed an increase in catalytic activity up to the loading of 12.5 wt% Ni, but adding more Ni caused a drop in catalytic activity. At this part, the catalyst containing 12.5 wt% weight with specific surface area of 156.22 m2/gr and conversion of methane and carbon dioxide equal to 78.2% and 80.7% at 700°C was selected as the best sample in terms of catalytic activity. The third part included the eva‎luation of the effect of operating conditions on the selected sample. The results of the activity test indicated an increase in methane conversion and a decrease in carbon dioxide conversion due to the increase in the amount of CO2 in the input feed. In addition, the results showed that a higher reduction temperature leads to the reduction of more nickel species and thus increases the catalytic activity. Finally, it was found that at GHSV=12000 ml/grcat.h, the reactants have more contact with each other, which improves the conversion. In the fourth part of the research, the effect of calcination temperature on the structural properties and catalytic activity of the 12.5% wt% Ni sample was investigated. Increasing the calcination temperature from 500°C to 700°C decreased the specific surface area from 156.22 m2/gr to 142.91 m2/gr. Also, the conversion of methane and carbon dioxide reached from 78.2% and 80.7% to 73.1% and 78.2% at 700°C, respectively.

ريفرمينگ خشك متان , گاز سنتز , كاتاليست , اكسيد ايتريم , نيكل , ارتقادهنده , آلومينا

dry reforming of methane , syngas , catalyst , yttrium oxide , nickel , promoter , alumina

Mohammad Reza Rajabi

Mehran Rezaei