Hydrogen from Renewables: A Case Study of Glycerol Reforming

Abstract

Biomass is an interesting candidate raw material for the production of renewable hydrogen. The conversion of biomass into hydrogen can be achieved by several processes. In particular, this short review focuses on the recent advances in glycerol reforming to hydrogen, highlighting the development of new and active catalysts, the optimization of reaction conditions, and the use of non-innocent supports as advanced materials for supported catalysts. Different processes for hydrogen production from glycerol, especially aqueous phase reforming (APR) and steam reforming (SR), are described in brief. Thermodynamic analyses, which enable comparison with experimental studies, are also considered. In addition, research advances in terms of life cycle perspective applied to support R&D activities in the synthesis of renewable H2 from biomass are presented. Lastly, also featured is an evaluation of the studies published, as evidence of the increased interest of both academic research and the industrial community in biomass conversion to energy sources.

Recent Advances in Glycerol Catalytic Valorization: A Review

“…For glycerol steam reforming, the main catalysts described are heterogeneous, and are similar to the ones used in other equivalent processes, such as methane steam reforming, especially in the case of supported noble and transition metal catalysts (with Ni as the most widely studied) [60,61]. As supports, different kinds of materials, such as alumina (such as Ni/Al 2 O 3 ), carbon (Pt/C), Ce and Zr oxides, and Mg oxides to a lesser extent, can be found in the literature [3,57]. Furthermore, perovskites based on Co and doped with Au, Ag, or Pt offered H 2 generation ranging from 70 to 90% [3].…”

“…Moreover, the higher the temperature is, the higher the production and selectivity of H 2 is, although it can also involve a decrease in the heating value of the resulting gas [20,59]. In contrast, as was previously pointed out, the main disadvantage of this process is the generation of CO 2 (which can be removed by in-situ adsorption), catalyst deactivation, and the high energy consumption [20,57]. Some authors have pointed out the possibility of re-using the CO 2 produced in this process for other purposes, such as coupling CO 2 desorption with methanation [18].…”

“…H 2 and syngas are potential alternative molecules obtained from biomass within the energy strategy of valorization, and are effective and clean energy carriers with an excellent storage capacity [46,57]. Therefore, they represent an interesting starting point for producing methanol, short-chain alcohol, detergents, ammonia, and synthetic hydrocarbon fuels for turbines or engines, among others.…”

A Short Overview on the Hydrogen Production Via Aqueous Phase Reforming (APR) of Cellulose, C6-C5 Sugars and Polyols

“…For instance, the increasing of polyol size generally leads to a consecutive decrease of hydrogen production, which fosters the light alkanes selectivity [21,22] . Additionally, for this reason, an impressive amount of work has been performed in the investigation of the APR of the simplest polyol, ethylene glycol (EG), and its higher, bio-based analogue, glycerol [9,21,23]. Figure 2, (adapted from Scopus ® ), shows the number of the peer review manuscripts containing the keywords "X aqueous phase reforming" (with X = methanol, ethanol, ethylene glycol, glycerol, sorbitol etc…) in the abstract, keywords, and titles published over a twenty years range.…”

MCM-41 Supported Co-Based Bimetallic Catalysts for Aqueous Phase Transformation of Glucose to Biochemicals

“…Glyceraldehyde can be hydrogenated to glycerol or rearranged to lactic acid, which can be further hydrogenated with propionic acid or decarboxylated to yield ethanol. Another pathway involving C-O and C-C cleavage leads to acetic acid, which can be obtained from glycerol [10][11][12][13][14].…”