Steam Reforming of Glycerol for Hydrogen Production over Ni/SiO2 Catalyst

G Sadanandam,S Kishta Reddy,M V Phanikrishna Sharma,V Durga Kumari,T Krishnudu,N Sreelatha,K Venkateswarlu,B Srinivas,M Subrahmanyam

doi:10.5402/2012/591587

G Sadanandam, S Kishta Reddy + Show 7 more

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https://doi.org/10.5402/2012/591587

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Abstract

The performance of Ni/SiO2 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/SiO2 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 H2 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).

Highlights

The search for alternative energy sources is becoming an important aspect in the present scenario due to diminishing petroleum reserves and increased environmental pollution
Aqueous phase reforming of oxygenated hydrocarbons is extensively studied by the Luo et al and Shabaker et al [9, 13], and glycerol steam reforming is studied by Czenik et al [14], Pompeo et al [10], and Adhikari et al [6, 15] over nickelbased catalysts and noble metal catalysts on different supports [16,17,18,19]
The thermodynamic analysis reported by Adhikari et al suggests the best conditions for hydrogen production at temperatures higher than 900 K under atmospheric pressure with 1 : 9 molar ratio of glycerol to water [6, 22]

Summary

Introduction

The search for alternative energy sources is becoming an important aspect in the present scenario due to diminishing petroleum reserves and increased environmental pollution. Besides converting glycerol into value-added chemicals [2,3,4], hydrogen production through reforming is alternative route [5,6,7,8,9,10,11,12]. Chiodo et al reported carbon formation of 2–6 mg carbon g−1 cat h−1 by steam reforming of glycerol by Ni over MgO, CeO2, Al2O3, and Ru/Al2O3 catalysts for 20 h [20]. Performance of metal-supported catalysts have been evaluated in terms of activity and hydrogen productivity, but no clear evidence has been reported to establish the most suitable catalyst system for glycerol steam reforming

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