Hydrogen Production By Glycerol Steam Reforming With Pt/SiO2 And Ni/SiO2 Catalysts

Hydrogen Production from renewable sources including biomass has importance in terms of renewable energy production now a days. Glycerol has high content of hydrogen and also its nontoxic nature, safety of storage and handling makes it more suitable for production of hydrogen. Steam reforming for production of hydrogen is one of the most used process in industries for H2 production. This process of production involves highly endothermic reaction and low pressures C3H8O3 (H2O)←→3CO + 4H2 (glycerol decomposition)CO + H2O ↔ CO2 + H2 (water–gas shift reaction) C3H8O3 + 3H2O ↔ 3CO2 + 7H2 (steam reforming of glycerol)CO + 3H2 ↔ CH4 + H2O (methanation reaction)

Catalyst used for this reaction of glycerol hydrogen production should have ability to cleavage bonds of C-C, C-H and O-H molecules to be reformed. Nickel is the one of the cheapest metal and active metal. By evaluating the performance of nickel over alumina modified by Ce and Zr at temperature more than 800 degree Celsius. The most stable was found to be Ni/CeO2/Al2O3. Ce has effect of inhibition of the reaction going parallel to main reaction forming unsaturated hydrocarbon that were formed from the coke. Other Catalyst selected is Palladium. Platinum Catalyst prepared by different methods and using supports of other metal oxides like SiO2, Al2O3, ZrO2, which were active in the range of 350–450 ◦C. The Ni and Pt catalyst were prepared at general room temperature by method of ion exchange with viscous liquid solution of Degussa silica. The content of metal obtained was 2 wt % for platinum and 5 wt % for nickel.

The final adjustment of catalyst was made to obtain 2 % and 0. 5% of Ni and Pt. The test of temperature program reduction test was carried out in dynamic equipment conventionally with ratio of hydrogen and nitrogen of 1/9 th and heating rate of 10 degree Celsius per min from the refrence room temperature upto the temperature of 1000 degree Celsius. Mean Particle size was obtained by TEM and measured in 100C TEM instrument. A Pattern was obtained for calibration. For size of particle, the assumption was made that particle were spherical and all the geometric parameter lie surface area, volume was calculated by following expression dva = , where di is diameter and ni is number of particle. Dynamic Equipment with Detector was used for Hydrogen Chemisorption measurements. A fixed Bed quartz reactor having internal diameter of 8 mm was operated isothermally at atmospheric pressure. The Ni catalyst was reduced from standard room temperature up to 500 degree Celsius. The injection of aqueous glycerol to the reactor was done by pump with feed flow of 0. 51 cm3 per min. Evaporator for this setup is quartz of 6mm diameter which is filled by pellets. This evaporator is heated by electric furnace. The carrier gas used for support was nitrogen. The space time which is indicated as per min was defined and calculated as grams of feed per min per gram of catalyst. This study face time was varying from the 0. 44 to 1. 65 min of catalyst mass. The Analysis of gas product was done by gas chromatograph detector, the liquid product was analyzed chromatographically with chrome pack and capillary column.

The accuracy of this experiment of measured values was within 5 percent error and relative error of 10 percent Gaseous Products (Carbon monoxide, Hydrogen, carbon dioxide and methane) converted from glycerol = The glycerol conversion to liquid products is indicated as XL and it was calculated based on the following equation: = * (100-) The composition of gas product [% mol/mol (dry)] was calculated as produced moles of H2, CO, CO2 and CH4, divided total moles of gas phase × 100. The activity on time was expressed as coefficient that expresses the ratio between gaseous glycerol conversion at time t divided the initial gaseous glycerol conversion. Temperature Programmed Reduction analysis was done for the catalyst concentration. The Platinium has two oxides with two type of interaction with certain temperature range. Weak interaction is under 220 degree Celsius and strong interaction supports from 350 degree Celsius. Regarding Nickel very broad reduction peak was seen between temperature range of 400 to 800 degree Celsius. Thus preparation of catalyst by ion exchange method makes formation of nickel silicates with high temperature stability.

First of all Ni catalyst was seen having lower conversion the platinum catalyst in some conditions. Regarding the concentration of gaseous, carbon monoxide appears to the primary product in produced gases. As the time of the reaction increases carbon dioxide and hydrogen production increases at expense of decrease in carbon monoxide. Methane still doesn’t show change. Platinium addition to nickel catalyst to generate 0. 5Pt-2Ni bimetallic catalyst which overall did not improved catalytic performance. Although the total conversion increased to certain extent but it was not possible to achieve 100% conversion to gases. This implies that electronic properties of Pt are affected reducing ability of C-C cleavage. The analysis of deposition of carbon was done by TPO/TGA analysis by collecting post reaction sample. Pt catalyst showed very less deposition of carbon as compared to nickel catalyst. It is seen that oxidation temperature can related to morphology of carbon decomposition The purpose of this experiment was to study different type of Ni and Pt catalyst in different composition having SiO2After study and analysis of experiment of steam reforming reaction of glycerol using different concentration and combination of Nickel and Platinum catalyst its been seen that it is possible to achieve the complete conversion to gases phase at 350 degree Celsius. The precise results were obtained with concentration of 2Pt at 450 degree Celsius, producing a completely gaseous state of 70 percent of Hydrogen, 6. 4 percent of carbon monoxide, 23 percent of Carbon Monoxide and remaining 0. 6% of methane. The activity test done in the experiment showed that 2Pt catalyst allowed total conversion to gas form, without any deactivation in between during 40 hours on stream at 350 degree Celsius. In was seen that both of catalyst 2Pt and 1Pt were stable at 450 degree Celsius.