Steam Reforming of Glycerol for Hydrogen Production over Ni/SiO 2 Catalyst

Abstract

The performance of Ni/SiO 2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO 2 catalysts of three sizes ( 2 × 2 , 2 × 4 , and 3 × 5 mm) are evaluated using glycerol: water mixture at 600 ° C to produce 2 L H 2 g −1 cat h −1 . The results indicate that 3 × 5 mm size pellet is showing minimum coking and maintaining same level of conversion even after several hours of reforming activity. Whereas studies on 2 × 2 and 2 × 4 mm pellets indicate that carbon formation is affecting the reforming activity. Under accelerated aging studies, with 1 : 9 molar ratio of glycerol to water, 3 mg carbon g −1 cat h −1 was generated in 20 cycles, whereas 1 : 18 feed produced only 1.5 mg carbon g −1 cat h −1 during the same cycles of operation. The catalysts were characterized before and after evaluation by X-ray diffraction (XRD), BET surface area, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDAX), CHNS analysis, transmission electron microscopy (TEM), and X-ray photo electron spectroscopy (XPS).