Boston University College of Engineering
Division of Materials Science and Engineering
 
Ph.D. Prospectus Defense of Soobhankar Pati
 
Friday, February 6, 2009
15 Saint Mary’s Street, Room 116
12:00PM-2:00PM

Committee:
Co-Advisor: Uday B. Pal, MSE/ME
Co-Advisor: Srikanth Gopalan, MSE/ME
Soumendra N. Basu, MSE/ME
Adam Powell, ME
 
Title:  Electrolyzer for Production of High Purity Hydrogen From a Source of Waste and Steam
 
Abstract:  Concerns about the depletion of fossil fuel reserves and global warming due to increase in atmospheric CO2 content make hydrogen based energy systems an attractive alternative energy source. However, presently all the hydrogen produced is dependent on a carbon positive energy source. A cleaner, reliable, cheaper hydrogen production route, which is independent of fossil fuel, is necessary for hydrogen to be used extensively as a fuel. In response to this challenge, this Ph.D. project is aimed at developing an electrolyzer that can utilize carbon-neutral energy sources such as waste to produce high purity hydrogen.
In this project a laboratory-scale solid oxide membrane (SOM) steam electrolyzer, that can utilize energy value in waste or any source of carbon or hydrocarbon to produce high purity hydrogen, will be fabricated. The SOM electrolyzer will consist of an oxygen-ion-conducting yttria-stabilized zirconia (YSZ) electrolyte with a dip coated Ni-YSZ cermet cathode on one side and liquid metal anode on the other side. The SOM electrolyzer will be operated at 800-1100 oC by providing a steam-rich gas feed to the Ni-YSZ cermet cathode and feeding a waste source into the liquid metal anode. An electrochemical process model for a SOM electrolyzer will be developed and the data obtained from electrochemical measurements such as AC impedance spectroscopy, potentio-dynamic scans will be fitted into the model to analyze the polarization losses. Chronoamperometric studies will be done to evaluate the long term performance of the SOM electrolyzer. The results obtained from the experimental study and theoretical modeling will form the basis for redesigning the SOM electrolyzer to improve its efficiency and durability. The SOM electrolyzer will also be operated with varying the steam content in the cathodic gas and based on these measurements an analytical model for cathode reaction will be developed.

The hydrogen production from waste using a SOM electrolyzer involves complex chemical, thermo-mechanical and electrochemical interactions between the different components. The proposed work will obtain a comprehensive understanding of such interactions by combining experimental and theoretical modeling approaches. The objective of this project is to identify key conditions for successful industrial implementation of the SOM electrolyzer technology utilizing different types of waste.