Coke Study on Water Pretreated Ni/Al2O3 for Combined Steam and Carbon Dioxide Reforming of Methane

摘要

Combined steam and carbon dioxide reforming of methane (CSCRM) can produce desired synthesis gas for Fischer–Tropsch and methanol synthesis due to adjust H2/CO ratio by controlling reacting gas composition. Compare to noble metal catalysts, Ni catalysts are economical and have been researched commonly. However, supported Ni catalysts easily deactivate due to carbon formation in carbon dioxide reforming of methane with and without steam (1). In this work, we found that simple pretreatment with water can significantly improve the conversion of methane and carbon dioxide and diminish carbon deposition greatly. Water pretreatment stabilized alumina in advance, minimizing aluminum leaching during the reaction and thereby limiting coke formation at the early stages of the reaction. Although the resulting catalyst after water pre-treatment had much larger Ni particles than conventional catalysts, the water-pretreated catalyst showed enhanced conversion and carbon resistance. This work shows that minimizing coke formation at initial reaction is a facile and effective method to enhance activity and long-term stability during methane reforming with steam and carbon dioxide.