Thesis
Study of the effect of water in steam reforming reaction and development of a stable and active nickel based catalyst
Washington State University
Master of Science (MS), Washington State University
2016
Handle:
https://hdl.handle.net/2376/101707
Abstract
The ever increasing energy demand and the corresponding fossil fuel scarcity has urged for alternative fuel sources. The growing environmental awareness has made the challenge even more difficult. Being a clean energy carrier, hydrogen has proved its position as one of the potential alternatives. Biomass derived bio-oil is the largest source of hydrocarbon that can be used as feedstock for hydrogen production by steam reforming. Apart from ethanol, acetic acid, acetone, phenol and their derivatives bio-oil contains considerable amount of water (15-30 %). Water plays a vital role in the reaction mechanism, product distribution and reaction kinetics. In this work, first, the effect of water on ethanol conversion over zinc oxide is studied. Water blocks the strong Lewis acid site to inhibit both the dehydration and dehydrogenation of ethanol. However, the extent of inhibition for the dehydration reaction is orders of magnitude higher than that for dehydrogenation reaction, leading to the shift of reaction pathway from ethanol dehydration to dehydrogenation. In the secondary reactions for acetaldehyde conversion, water inhibits the acetaldehyde aldol-condensation to crotonaldehyde, favoring the oxidation of acetaldehyde to acetic acid, and then to acetone via ketonization at high temperature (i.e., 400 °C). In the next work, a stable and active nickel based catalyst is developed for simulated bio-oil. Magnesium oxide, ceria, copper oxide were used as additives for nickel based catalyst for improving the issues like water gas shift (WGS) activity, coke formation and sintering. Potassium was used as a dopant to reduce the methane formation. The additives showed better activity on [gamma] Al2O3 support than on the TiO2. The conversion and hydrogen yield were almost double on [gamma] Al2O3 support than on the TiO2. Nickel is well known for promoting methanation reaction instead of WGS reaction. The addition of potassium dopant dropped the methane selectivity from 12% to 2% at similar conversion. For, reducing the effect of coking and improving the catalyst stability, periodic regeneration was applied to the catalyst. This periodic steam reforming and regeneration showed stable and active performance for 10 cycles indicating a durable catalyst can be achieved through systematic regeneration.
Metrics
4 File views/ downloads
14 Record Views
Details
- Title
- Study of the effect of water in steam reforming reaction and development of a stable and active nickel based catalyst
- Creators
- Md Mahfuzur Rahman
- Contributors
- Yong Wang (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525392501842
- Language
- English
- Resource Type
- Thesis