Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2018
Student: NURBANU ÇAKIRYILMAZ
Supervisor: NURAY OKTAR
Abstract:Hydrogen, utilized as alternative fuel, was produced from biomass oriented acetic acid via catalysts having high activity and resilience to coke formation. Cu, Ni and/or W were used as active materials in the synthesis of silica (MCM-41, SBA-15)/ zirconium supported catalysts. Structural and physical properties of synthesized catalysts were determined by XRD, N2 adsorption-desorption, FT-IR, ICP-MS, SEM and TEM analyses. Effects of support material, nickel amount, addition of Cu or W, tungsten amount, reaction temperature and acetic acid/water amount in feed on catalytic activity were investigated. Catalytic activity tests were initially conducted in a packed bed flow reactor heated with conventional system. Catalysts with highest activity were further tested in a microwave reactor system operated with high energy yield. Results obtained in conventional system for Cu and Ni containing catalysts revealed lower hydrogen yield in the presence of Cu in catalyst structure. 5Ni@SBA-15 catalyst exhibited highest activity among mono-metallic catalysts with 100% acetic and conversion and 7% coke formation. Coke formation was evident with MCM-41 and Zr-SBA-15 supported Ni catalysts. On the other hand, higher resistance to its formation was achieved by W addition on catalyst structure. Formation of synthesis gas was also observed via W addition. Increasing W amount from 10-50% in 25Zr-SBA-15 Ni catalysts resulted in the increase of synthesis gas utilized in production of liquid hydrocarbons having H2/CO ratio of 1 and/or production of alternative diesel fuel synthesis. Spent catalysts were analyzed by XRD, TGA-DTA and SEM against coke formation. Results obtained with TGA analyses showed that the amount of coke formed after reaction could be reduced to 1% with the addition of W on the structure. Hydrogen production with energy conservation up to 20 fold was obtained in microwave heated reactor compared to its conventional alternative.