Steam reforming of ethanol for hydrogen production: influence of catalyst composition (Ni/Al2O3, Ni/Al2O3–CeO2, Ni/Al2O3–ZnO) and process conditions

Abstract

Ethanol steam reforming was studied over Ni supported catalysts. The effects of support (Al2O3, Al2O3–ZnO, and Al2O3–CeO2), metal loading, catalyst activation method, and steam-to-ethanol molar feed ratio were investigated. The properties of catalysts were studied by N2 physisorption, TPD-CO2, X-ray diffraction, and temperature programmed reduction. After activity tests, the catalysts were analyzed by TOC analysis. The catalytic activity measurements showed that the addition either of ZnO SSor CeO2 to alumina enhances both ethanol conversion and promotes selectivity towards hydrogen formation. The same effects were observed for catalysts with higher metal loadings. High process temperature and high water-to-ethanol ratio were found to be beneficial for hydrogen production. An extended catalyst stability tests showed no loss of activity over 50 h on reaction stream. The TOC analysis of spent catalysts revealed only insignificant amounts of carbon deposit.

Insights into the Reaction Routes for H2 Formation in the Ethanol Steam Reforming on a Catalyst Derived from NiAl2O4 Spinel

“…However, the Al 2 O 3 acid sites also catalyze the ethanol dehydration, eq , yielding ethylene that undergoes decomposition to yield carbon material and H 2 through eq . The use of basic supports or the combination of basic oxides with Al 2 O 3 , such as La 2 O 3 , CeO 2 , ZnO, or ZrO 2 , improves the dispersion, prevents the sintering of the metal particles, and favors some reactions boosting the H 2 yield. − The presence of these oxides improves the oxygen mobility and the H 2 O adsorption and dissociation, resulting in promoting steam reforming reactions, eqs , , , and , the water–gas shift reaction, eq , and coke gasification, eq . The addition of basic promoters, such as CaO, reduces the support acidity and decreases the interaction between the metal precursor and the support, thus enhancing the formation of the metal particles onto the support .…”

The current status of hydrogen energy: an overview

“…[40][41][42][43] Conventional steam reformers are constrained by the efficacy factor of pelletized catalysts due to signicant mass and heat transmission restrictions. 44 Therefore, with traditional steam reformer reactors, kinetics is seldom the limiting factor, and as a result, less costly nickel catalysts are utilized in industry. 45,46 In general, steam reforming will continue to be the dominant source of hydrogen fuel in the coming decade because it has an established industrial production system, an assured supply of input fuel, and an optimized manufacturing method that yields the highest quality product.…”

CeO2-supported Ni and Co catalysts prepared by a solution combustion method for H2 production from glycerol: the effect of fuel/oxidizer ratio and oxygen excess

“…Ni-containing catalysts are known to have a high capability for C-C, C-H and O-H bond cleavage 10 and can be easily dispersed on a range of supports. A number of nickel catalysts supported on Al 2 O 3 , [11][12][13][14][15][16][17][18][19][20] CeO 2 , 17,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] MgO, 21,22,30 TiO 2 , 21,22,38 SiO 2 , 13,[38][39][40] and ZrO 2 (ref. 13, 38, and 41-44) have been studied in reforming processes of several renewable feeds, including methanol, 9 ethanol, [14][15][16][17]24,26,27,[32]…”

“…A number of nickel catalysts supported on Al 2 O 3 , 11–20 CeO 2 , 17,20–37 MgO, 21,22,30 TiO 2 , 21,22,38 SiO 2 , 13,38–40 and ZrO 2 (ref. 13, 38, and 41–44) have been studied in reforming processes of several renewable feeds, including methanol, 9 ethanol, 14–17,24,26,27,32–34,37,39,41 and glycerol. 11–13,20–23,25,28–31,35,36,38,40,42–44 Al 2 O 3 and CeO 2 as supports are considered effective in terms of high H 2 production and lower coke formation.…”