Mohammad Tazli Azizan

Reforming of glycerol for hydrogen production over Ni based catalysts: Effect of support type

ABSTRACT This current work focuses on hydrogen production that is a component in syngas by glycerol dry reforming over 15% nickel (Ni) loading supported on different oxides, namely CaO, ZrO2, and La2O3. The screening process was conducted in a fixed-bed reactor at 700°C under atmospheric pressure. It was found that 15% Ni/CaO showed the best performance in screening studies. The effect of temperature and the carbon to glycerol ratio (CGR) was then analyzed for this catalyst. From the analysis, it was seen that 15% Ni/CaO has its optimum condition at 800°C and CGR = 1, where it gives the highest glycerol conversion (XG = 37.66%) and hydrogen yield (YH = 32.45%).

Thermodynamic Analysis of Autothermal Reforming of Oxygenated Hydrocarbons at Thermoneutral Condition for Hydrogen Production

The thermodynamic analysis of autothermal reforming of homologue series consisted of ethanol, ethylene glycol, propylene glycol and glycerol representing oxygenated hydrocarbons were studied. The main investigation was to compare the effect of thermoneutral condition where no external air/oxygen supplied for the reaction to sustain and controlled amount of air/oxygen supplied. It was found that the higher number of oxygen atoms in these homologues molecule, the higher tendency of the reaction to be sustained at the desired temperature, and thus it only requires lesser amount of air for heating. The hydrogen selectivity however depends on the ratio of hydrogen atoms with respect to the oxygen atoms in each molecule. The presence of air however, though providing extra heating to the reactor, is offset by a lower hydrogen production.

Catalytic Hydrodeoxygenation of Rubber Seed Oil over Sonochemically Synthesized Ni-Mo/γ-Al2O3 Catalyst for Green Diesel Production

Hydrodeoxygenation is one of the promising technologies for the transformation of triglycerides into long-chain hydrocarbon fuel commonly known as green diesel. The hydrodeoxygenation (HDO) of rubber seed oil into diesel range (C15-C18) hydrocarbon over non-sulphided bimetallic (Ni-Mo/γ-Al2O3 solid catalysts were studied. The catalysts were synthesized via wet impregnation method as well as sonochemical method. The synthesized catalysts were subjected to characterization methods including FESEM coupled with EDX, XRD, BET, TEM, XPS, NH3-TPD, CO-chemisorption and H2-TPR in order to investigate the effects of ultrasound irradiations on physicochemical properties of the catalyst. All the catalysts were tested for HDO reaction at 350 °C, 35 bar, H2/oil 1000 N (cm3/cm3) and WHSV = 1 h-1 in fixed bed tubular reactor. The catalyst prepared via sonochemical method showed comparatively higher specific surface area, particles in nano-size and uniform distribution of particle on the external surface of the support, higher crystallinity and lower reduction temperature as well as higher concentration of Mo4+ deoxygenating metal species. These physicochemical properties improved the catalytic activity compared to conventionally synthesized catalyst for HDO of rubber seed oil. The catalytic performance of sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst (80.87%) was higher than the catalyst prepared via wet impregnation method (63.3%). The sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst is found to be active, produces 80.87 wt% of diesel range hydrocarbons, and it gives high selectivity for Pentadecane (18.7 wt%), Hexadecane (16.65 wt%), Heptadecane (24.45 wt%) and Octadecane (21.0 wt%). The product distribution revealed that the deoxygenation reaction pathway was preferred. Higher conversion and higher HDO yield in this study are associated mainly with the change in concentration ratio between oxidation states of molybdenum (Mo4+, Mo5+, and Mo6+) on the external surface of the catalyst due to ultrasound irradiation during the synthesis process. Consequently, the application of sonochemically synthesized non-sulphided catalysts favored mainly hydrodeoxygenation of diesel range hydrocarbon.

Effects of Ultrasound Irradiation on Synthesis of Solid Acid Catalysts

The studies based on morphological characterization to assess the effects of ultrasound irradiation on synthesis of solid acid catalysts. Three sets of catalyst formulation were synthesized by both wet impregnation method and ultrasound assisted methods with different wt. % of Ni loading on γ-Al2O3. The XRD, BET, TEM and FESEM techniques were used to characterize the nano-particles. Physicochemical characterization revealed that the synthesized catalysts particles using ultrasound irradiation were in nano size range (1-24.5 nm) with equal dispersion of metal oxide, high surface area with increase of metal loading and high phase purity than the catalysts synthesized conventional method. These catalysts were also found in various crystal structures like cubic, monoclinic and tetrahedral. The use of ultrasound irradiation has great significance over the wet impregnation method in relation to the rate of synthesis of nanocatalysts. The high surface area, high thermal stability and small particle size (up to 1 nm) are the basic elements for high activity of solid acid catalysts in hydrocracking and hydrodeoxygenation of various feedstock in petroleum industries.

Ethanol Steam Reforming over Calcium Doped Ni/Al2O3 Catalyst

Steam reforming of ethanol has been carried out using a commercial catalyst (Hi-FUEL) of calcium doped nickel/alumina catalyst. Hi-FUEL had successfully reformed ethanol into the desired products at relatively high yield and selectivity. The hydrogen yield of 90.5% has been achieved from this catalyst with almost no ethylene detected. Hi-FUEL is also comparable with other calcium doped nickel/alumina catalyst as reported by other researchers.