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

Glycerol, byproduct from the biodiesel production can be effectively utilized as the promising source of synthesis gas (syngas) through a dry reforming reaction. Combination of these waste materials with greenhouse gases which is carbon dioxide (CO2) will help to reduce environmental problem such as global warming. This dry reforming reaction has been carried out in a fixed bed batch reactor at 700 °C under the atmospheric pressure for 3 hours. In this experiment, reforming reaction was carried out using Nickel (Ni) as based catalyst and supported with zirconium (ZrO2) and calcium (CaO) oxides. The catalysts were prepared by wet impregnation method and characterized using Bruanaer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Thermo Gravimetric (TGA), and Temperature Programmed Reduction (TPR) analysis. Reaction studies show that 15% Ni/CaO give the highest hydrogen yield and glycerol conversion that peaked at 24.59% and 30.32%, respectively. This result is verified by XRD analysis where this catalyst shows low crystallinity and fine dispersion of Ni species resulted in high specific surface area which gives 44.93 m2/g that is validated by BET. 

Hydrogen production via Co2 dry reforming of glycerol over Re-Ni/Cao catalysts

Hydrogen (H2) has become a promising alternative energy source due to its high efficiency, clean emission and impact in reducing the dependency on non-renewable energy sources [1]. Glycerol has become one of the attractive feedstock for H2 production and it has received considerable attentions from researchers worldwide [2,3]. Glycerol dry reforming offers a better pathway for the production of H2 as it is reported to have a greener process where it utilize waste products; glycerol and greenhouse gases (CO2) as its feedstock. This dry reforming reaction was carried out over two catalysts which is 15%Ni/CaO and 5%Re-Ni/CaO in a packed bed reactor with CGR ratio of 1 – 5, reaction temperature of 600 – 900 °C and GHSV of 1.44 x 104 – 7.2 x 104 ml gcat-1 s-1. From the characterization analyses, fresh 5%Re-Ni/CaO catalyst was found to have lower specific surface area when compared to 15%Ni/CaO due to the plugging of pore. The addition of Re also improved the reduction temperature and contributed to higher acidic sites concentration, hence, improving the catalytic activity of the reaction by enhancing the surface adsorption of OH group in glycerol. From the reaction studies, it was found that suitable operating condition for both catalysts was at 800°C and GHSV of 3.6×104 hh-1 with CGR of 1.0 for non-promoted and CGR of 3.0 for promoted catalyst. Hydrogen gas was directly produced from glycerol decomposition and indirectly produced through the water gas shift reaction. Post reaction analysis of the spent catalysts using FESEM-EDX and TPO analysis showed existence of whisker carbon from the CO2 hydrogenation and methanation process

Extraction and isolation of kappa carrageenan from red seaweeds

This works present the extraction and isolation process of kappa carrageenan from red seaweed. Product from this research can be use in pharmaceutical industry for production of capsule as it give advantages in aspect of economical, health and cultural. To extract and isolate kappa carrageenan, alkali treatment and alcohol precipitation was involved. In the alkali treatment of extraction process, three variables (i.e. temperature, concentration and time) have been investigated whereas in isolation process, isopropanol was used to study the separation of kappa carrageenan through precipitation. Based on experimental analysis, alkali treatments influence the yield, rheological and physichochemical properties of kappa carrageenan. Increasing potassium hydroxide (KOH) concentration decreased the yield and viscosity of kappa carrageenan due to degradation of polysaccharides. Temperature and time gave insignificant effect to the properties of extracted carrageenan. From the experimental result, the extraction and isolation of kappa carrageenan has been successfully conducted. Therefore, the range of concentration, temperature and time used in this analysis is acceptable to extracte and isolate kappa carrageena

Dry reforming for glycerol hydrogen-rich production over Ni/CaO, Ni/ZrO2 and 5%Re-Ni/CaO

Increase in biodiesel production has lead towards a glut production of glycerol where it is estimated that 3 megatons of crude glycerol will be produced by 2020. This leads towards oversupply crisis of glycerol and simultaneously influences its market price. Conversion of glycerol into hydrogen via dry reforming is a potential alternative to overcome this crisis which helps to overcome the environmental problems related with the greenhouse gases production. This work focused on the feasibility of glycerol dry reforming over a series of synthesised catalysts. In this work, nickel was supported with different oxides namely calcium oxide and zirconium oxide. The best oxide support was then promoted with rhenium via wet impregnation technique. The reaction was conducted in a stainless-steel fixed bed reactor at various temperatures of 600–900 °C, carbon dioxide to glycerol ratios of 1, 3, and 5, and gas-hourly space velocity (GHSV) of 7.20 × 104 to 1.44 × 104 mL gcat-1 h-1. The physichochemical characterisations of the catalysts were analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption, temperature programmed calcination (TPC), temperature-programmed oxidation (TPO), and field emission scanning microscopy/energy dispersive X-ray analysis (FESEM-EDX). In the screening stage, the Ni/oxide support loadings were varied and carried out at a fixed reaction condition of T (700 °C), CGR (1), and GHSV (3.6 × 104 mL gcat-1 h-1). Based on the screening study, 15%Ni/CaO exhibited smaller crystallite size that leads to well dispersion of NiO and high catalysts specific surface area. In TPD-NH3 analysis, 15%Ni/CaO possessed greater basic site concentration that helped in suppressing the carbon deposition. In the reaction study, this catalyst achieved 32.33% of glycerol conversion and 28.83% of hydrogen yield. After selecting the best catalyst support, the properties of the catalyst was enhanced with the addition of 5%Re as the catalyst promoter. For 5%Re-Ni/CaO catalyst, the crystallite size was found to be small within the range of 0.49 to 0.90 nm. This condition has significantly reduced the specific surface area of the catalyst due to the partial blockage of catalyst support. Besides that, Re promotion also helped to speed up the reduction of NiO to Ni and increased the acid site of catalyst. This condition has improved the catalytic activity of the promoted catalyst up to 44% of glycerol conversion. From the reaction study, the highest glycerol conversion and hydrogen yield were successfully achieved at the temperature of 800 °C and GHSV of 1.44 × 104 mL gcat-1 h-1 with CGR of 1 for non-promoted catalyst and CGR of 3 for promoted catalyst. It is determined that hydrogen gas was majorly produced from glycerol decomposition and indirectly from water gas shift reaction. Increment of temperature and GHSV beyond the optimum point is not beneficial due to the CO2 hydrogenation and methanation processes that built up of carbon deposition on the surface of catalyst. The formation of whisker carbon for both catalysts is proven in FESEM-EDX and TPO analysis

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

Glycerol, byproduct from the biodiesel production can be effectively utilized as the promising source of synthesis gas (syngas) through a dry reforming reaction. Combination of these waste materials with greenhouse gases which is carbon dioxide (CO2) will help to reduce environmental problem such as global warming. This dry reforming reaction has been carried out in a fixed bed batch reactor at 700 °C under the atmospheric pressure for 3 hours. In this experiment, reforming reaction was carried out us-ing Nickel (Ni) as based catalyst and supported with zirconium (ZrO2) and calcium (CaO) oxides. The catalysts were prepared by wet impregnation method and characterized using Bruanaer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Thermo Gra-vimetric (TGA), and Temperature Programmed Reduction (TPR) analysis. Reaction studies show that 15% Ni/CaO give the highest hydrogen yield and glycerol conversion that peaked at 24.59% and 30.32%, respectively. This result is verified by XRD analysis where this catalyst shows low crystallin-ity and fine dispersion of Ni species resulted in high specific surface area which gives 44.93 m2/g that is validated by BET

Reforming of Glycerol for Hydrogen Production over Ni Based Catalysts: Effect of Support Type

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%)

Characterization of Ni catalyst supported on α-Al2O3 and SiO2 for syngas production via dry reforming of glycerol

Ni-based catalysts supported on α-Al2O3 and SiO2 were prepared through wet impregnation method for glycerol dry reforming to produce hydrogen, carbon monoxide and methane. Glycerol dry reforming was carried out in tubular reactor at 973 K under atmospheric pressure. The catalysts were characterized using X-Ray Diffraction, Bruneuer-Emmet Teller surface area, Thermogravimetric Analysis, temperature-programmed reduction and Scanning Electron Microscopy. Ni/Al2O3 gives the higher glycerol conversion and hydrogen yield (14.46% and 9.82% respectively) compared to Ni/SiO2. This result was due to smaller crystallite size and higher specific surface area of Ni/Al2O3 compared to Ni/SiO2. Additionally, the nature of Al2O3 could increase metal dispersion as well as avoid the carbon deposition, helps the activity and the stability of this catalyst. The deposition of encapsulated carbon and filamentous carbon could be observed on Ni/Al2O3 and Ni/SiO2, respectively, and can be easily removed through oxidation

Hydrogen production by glycerol dry reforming over rhenium promoted Ni-based catalyst supported on Santa Barbara Amorphous 15 (SBA-15)

This paper presents the glycerol dry reforming (GDR) reaction using rhenium (Re) promoted on Ni-based catalyst supported on Santa Barbara Amorphous 15 (SBA-15) for the production of hydrogen. In this study, the non-promoted (15%Ni/SBA-15) and promoted (3%Re-15%Ni/SBA-15) catalysts were first synthesized using wet impregnation method and their physicochemical characteristics were analyzed with Brunauer–Emmet–Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric (TGA) analyses. Their performances were evaluated in GDR reaction and it was found that 3%Re-15%Ni/SBA-15 exhibited higher glycerol conversion (57%) and hydrogen yield (55%) than 15%Ni/SBA-15 (i.e., 20% glycerol conversion and 18% hydrogen yield). From the GDR study, the highest glycerol conversion (57%) and hydrogen yield (55%) for 3%Re-15%Ni/SBA-15 were obtained at 0.2 g catalyst, 700°C of reaction temperature, and CO2 to glycerol ratio (CGR) of 1:1. The small crystallite size and BET surface area of 3%Re-15%Ni/SBA-15 had successfully reduced the carbon deposition and indirectly contributed to high glycerol conversion and product yield