Valorization of alcoholic wastes from the vinery industry to produce H2

Abstract

This paper focuses on the development of active and stable catalysts for the steam reforming of alcoholic wastes. Two catalysts with high activity in the steam reforming of ethanol have been studied in the steam reforming of an alcoholic waste from the vinery industry, as previous step to their industrial scale up. The catalysts are based on cobalt supported on Zn-hydrotalcite-derived material and natural sepiolite. At laboratory level, the catalytic material based on natural sepiolite showed the best catalytic performance maintaining its catalytic activity for more than 160 hours in presence of 50 ppm of sulfur contained in the alcoholic waste. Thus, sepiolite based catalyst was scaled up to prepare a first generation of catalytic monoliths. The reforming activity of this first generation of monoliths was found lower than their corresponding powdered catalyst. The high calcination temperature (1573 K) used in the manufacture of the first generation of monoliths was the responsible of their low performance, which was related to the sintering of cobalt catalyst in a larger crystallite size of metallic cobalt. A second generation of monoliths was prepared using a lower calcination temperature (873 K). Now, the monoliths exhibited a high catalytic performance, similar to the powdered catalyst. The excellent results obtained with the second generation of monoliths have been protected under an invention patent (E201731077). This is the first time that catalytic monoliths based on natural sepiolite promoted with Co are successfully manufactured and tested in the steam reforming of alcoholic wastes from the distillery industry to produce hydrogen.

Sustainable production of hydrogen via steam reforming of furfural (SRF) with Co-catalyst supported on sepiolite

“…Co has an optimal performance at moderate temperatures and the substitution of precious metals by Co supposes a great advantage from the economic point of view. The optimal performance of Co is related to the facility that this metal has to carry out the scission of the C-C and O-H bonds [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. In general, the adequate catalytic performance of one catalyst is determined by three main parameters: activity, selectivity, and stability.…”

“…Among them, support is one of the most important factors to consider. Nature of the support is crucial to synthesize highly active, selective and stable steam reforming catalysts, because it can favor high dispersions of the active metal phase of the catalysts and favor metal-support interactions that improve the catalytic performance [39][40][41]. The method to incorporate the active phase (metals) is another important issue to synthesize efficient catalysts.…”

Sustainable Production of Hydrogen by Steam Reforming of Ethanol Using Cobalt Supported on Nanoporous Zeolitic Material

“…However, each catalyst induces different reaction pathways and, therefore, the selection of the suitable catalyst is a key factor in the SR of bioethanol. The studies show that the best catalytic results are exhibited by Ni and Co among the non-noble metals [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The main problems during the catalytic steam reforming of bioethanol are: (i) sintering of active metal and catalyst poisoning by coke depositing at high temperature, and (ii) formation at moderate temperatures of undesired products such as acetaldehyde, diethyl ether, acetic acid, or ethylene.…”

“…The main problems during the catalytic steam reforming of bioethanol are: (i) sintering of active metal and catalyst poisoning by coke depositing at high temperature, and (ii) formation at moderate temperatures of undesired products such as acetaldehyde, diethyl ether, acetic acid, or ethylene. All these problems were found to be related to the physicochemical properties of the catalyst, which highly depend on: the nature of the metal active site, the preparation methods, the type of metal precursors used, the nature of metal support, the presence of additives, and the operating conditions [ 32 , 33 , 34 ]. Among them, support plays a crucial role in the preparation of highly active and selective catalysts for the steam reforming of bioethanol, since it favors the dispersion of metal in the catalyst and increases its activity through metal-support interactions [ 32 , 33 , 34 ].…”

“…All these problems were found to be related to the physicochemical properties of the catalyst, which highly depend on: the nature of the metal active site, the preparation methods, the type of metal precursors used, the nature of metal support, the presence of additives, and the operating conditions [ 32 , 33 , 34 ]. Among them, support plays a crucial role in the preparation of highly active and selective catalysts for the steam reforming of bioethanol, since it favors the dispersion of metal in the catalyst and increases its activity through metal-support interactions [ 32 , 33 , 34 ]. Specifically, it has been found that the high specific surface of the support may enhance the catalytic activity [ 16 , 35 ], and its topology and the crystal structure may affect the dispersion of the metal particles, improving their stability against sintering [ 28 , 36 ].…”