Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al_S.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al_S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al_S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

Owing to the high energy content of hydrogen and the possibility of converting this energy in fuel cell devices into electric power without any pollutant emissions, hydrogen has grown to be one of the most useful sources of energy, especially if it is produced from renewable sources. In recent years, the development of an efficient process for hydrogen production has become an important goal for energy researchers. Numerous studies have evaluated the catalytic reforming of glycerol for hydrogen production both experimentally and thermodynamically. To enhance hydrogen production and make the production process efficient, researchers have investigated different reforming processes under a wide range of operating conditions. Moreover, the main focus of these studies was the development of a high-performance reforming catalyst that can increase the hydrogen yield and decrease carbon formation and processing costs. Several reforming processes can be used to produce hydrogen from glycerol. This article reviews these reforming processes with emphasis on the common catalysts and the operating conditions used in thermodynamic analyses and experimental work. Although most of these studies have been conducted on steam and aqueous-phase reforming processes, more work on other reforming processes, such as autothermal reforming, partial oxidation, supercritical water, and photo-catalytic reforming, has yet to be completed.

In this work, catalytic steam reforming of glycerol for hydrogen production was performed over Ce/Al₂O₃ and Pd/Al₂O₃ catalysts prepared via the impregnation method. The catalysts were characterized by scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), BET surface area, and X-ray diffraction (XRD). Two sets of catalytic reactions were conducted, one comparing 1% Pd/Al₂O₃ to 1% Ce/Al₂O₃ and the second comparing 1% Ce/Al₂O₃ loading to 10% Ce/Al₂O₃ loading. All catalytic reactions were performed using a fixed-bed reactor operated at 600 °C and atmospheric pressure. Aglycerol–water mixture at a molar ratio of 1:6 was fed to the reactor at 0.05 ml/min. In the first set of experiments, Pd/Al₂O₃ exhibited higher hydrogen productivity than Ce/Al₂O₃. A maximum hydrogen yield of 56% and a maximum selectivity of 78.7% were achieved over the Pd/Al₂O₃ catalyst. For the second set of experiments, the results show that the reaction conversion increased as the cerium loading increased from 1% to 10%. A total average hydrogen yield of 28.0% and a selectivity of 45.5% were obtained over 1% Ce/Al₂O₃, while the total average hydrogen yield and selectivity were 42.2% and 52.7%, respectively, for 10% Ce/Al₂O₃.

In this work; a response surface methodology (RSM) was implemented to investigate the process variables in a hydrogen production system. The effects of five independent variables; namely the temperature (X₁); the flow rate (X₂); the catalyst weight (X₃); the catalyst loading (X₄) and the glycerol-water molar ratio (X₅) on the H₂ yield (Y₁) and the conversion of glycerol to gaseous products (Y₂) were explored. Using multiple regression analysis; the experimental results of the H₂ yield and the glycerol conversion to gases were fit to quadratic polynomial models. The proposed mathematical models have correlated the dependent factors well within the limits that were being examined. The best values of the process variables were a temperature of approximately 600 °C; a feed flow rate of 0.05 mL/min; a catalyst weight of 0.2 g; a catalyst loading of 20% and a glycerol-water molar ratio of approximately 12; where the H₂ yield was predicted to be 57.6% and the conversion of glycerol was predicted to be 75%. To validate the proposed models; statistical analysis using a two-sample t-test was performed; and the results showed that the models could predict the responses satisfactorily within the limits of the variables that were studied.