Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst

Abstract

Glycerol (a bio-waste generated from biodiesel production) has been touted as a promising bio-syngas precursor via reforming route. Previous studies have indicated that carbon deposition is the major performance-limiting factor for nickel (Ni) catalyst during glycerol steam reforming. In the current paper, dry (CO2)-reforming of glycerol, a new reforming route was carried out over alumina (Al2O3)-supported nonpromoted and lanthanum-promoted Ni catalysts. Both sets of catalysts were synthesized via wet coimpregnation procedure. The physicochemical characterization of the catalyst showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. In addition, BET surface area measurement gave 92.05m²/g for non-promoted Ni catalyst whilst promoted catalysts showed an average of 1 to 6% improvement depending on the La loading. Reaction studies at 873 K showed that glycerol dry reforming successfully produced H2 with glycerol conversion and H2 yield that peaked at 9.7% and 25% respectively over 2wt% La content. The optimum catalytic performance by 2%La-Ni/Al2O3 can be attributed to the larger BET surface area and smaller crystallite size that ensured accessibility of active catalytic area.

Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts

“…Syngas is touted as the promising alternative energy due to its high efficiency, clean emission and it helps to reduce the dependency on these non renewable sources [1]. Syngas or synthesis gas is comprised mainly of hydrogen (H2) and carbon monoxide (CO2) and it was used as feedstock in several of process like Fischer-Tropsch, methanol, ammonia and synthetic natural gas [2].…”

“…Commercially, syngas is produced through the natural gas steam reforming where steam (H2O) is use as feedstock and CO2 is produced as its byproduct. This process is found to contribute to energy-intensive related problem and the releases of greenhouse gases, carbon dioxide (CO2) that contributed to the global warming problems [1][2]. Besides that, steam reforming produces several side reactions such as carbon formation, methanation and reverse watergas shift [7,[9][10][11] that affecting the purity of the reforming product [12] .…”

“…(1) Prior works has been done on the glycerol dry reforming, concentrating on the thermodynamic analysis and effect on different types of support and promoters over Nickel (Ni) based catalyst [1,[13][14]. Wang and co workers [15] has performed the thermodynamic analysis using Gibbs free energy method and found that the maximum quantities of syngas can be reached at atmospheric pressure where the temperature is set at 1000 K. Lee et al [13] reported on the use of cement clinker as support for the Ni based where the reaction temperature was held at 1023 K. In the experiment, the CO2 to glycerol ratio (CGR) was manipulated with the pressure of CO2.…”

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

“…Interestingly, the peaks of AgSi in Ag(1)-Ni/SiO2 and Ag(2)-Ni/SiO2 appeared between 2θ of 29.0° to 80.0° are short and unnoticeable, indicates the weak dispersion of Ag with the catalyst support at low Ag loading. The short peaks indicate the formation of small crystalline particles, which might cover the active sites of the catalyst [9].…”