Catalysis Today, Vol.309, 140-146, 2018
Rapid evaluation of coke resistance in catalysts for methane reforming using low steam-to-carbon ratio
The formation and subsequent accumulation of coke is one of the major reasons for the catalyst deactivation in methane reforming reaction. Although the investigation of coke-resistant catalysts is closely related to their long-term stability of given catalysts, it takes a long time to quantitatively measure the amount of carbon deposition on catalysts under normal reaction operational conditions. To overcome this problem, we used the steam deficient reaction condition, i.e. a low steam-to-carbon ratio (S/C) of 0.5 to accelerate the carbon deposition on catalysts. In this condition, the base catalyst of 10 wt.% Ni/alumina rapidly lost its catalytic activity, indicating fast coke deposition. However, adding proper additives, such as Ru among various precious metals (Ru, Rh, Pt, and Pd) and alkaline earth metals (Mg, Ca, Sr, and Ba) with the appropriate loading (5 wt.%) effectively suppressed coke formation. The optimized catalyst composition is 0.5 wt.% Ru/5 wt.% Mg/10 wt.% Ni/alumina, which displayed coke resistance in the long-term stability test of steam methane reforming and 40 h test of dry reforming of methane. These experimental results indicate that the method developed in this study is useful for the rapid evaluation of given catalysts for their coke resistance.