Influence of nitrogen on the catalytic behaviour of Pt/γ-Al2O3 catalyst in glycerol reforming process

In the present work, deactivation behaviour of a Pt/γ-Al2O3 catalyst used for converting glycerin/water mixture into hydrogen was investigated. It was shown that main reason for the catalyst activity drop is due to the carbon deposition over the catalyst surface. Interestingly, the catalyst suffered from faster deactivation in the case of nitrogen presence in the inlet stream. However, the catalytic stability of the catalyst could be greatly enhanced when nitrogen was phase out from the reaction atmosphere. In the reaction mixture containing 10 wt% glycerol, the deactivation constant of the catalyst decreased from dA = −0.0516 mL/(min gcat. h) under a condition with nitrogen to dB = −0.0051 mL/(min gcat. h) without nitrogen in the reaction bed. Catalytic evaluation and thermogravimetric analysis revealed that nitrogen was not only an inert carrier gas served as but also an accelerator for coking. A speculation model was proposed for explanation of the coking process over the catalyst with the nitrogen effect.