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AN INTEGRATED ‘ONE-BOX’ PROCESS
FOR HYDROGEN PRODUCTION
by
Mitra Abdollahi
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(CHEMICAL ENGINEERING)
May 2011
Copyright 2011 Mitra Abdollahi
Object Description
| Title | An integrated 'one-box' process for hydrogen production |
| Author | Abdollahi, Mitra |
| Author email | abdollah@usc.edu; mitra_abd100@yahoo.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2011-03-11 |
| Date submitted | 2011 |
| Restricted until | Restricted until 03 Nov. 2011. |
| Date published | 2011-11-03 |
| Advisor (committee chair) | Tsotsis, Theodore T. |
| Advisor (committee member) |
Sahimi, Muhammad Pirbazari, Massoud |
| Abstract | Hydrogen is widely considered as a fuel for the future to address the energy crisis and the environmental concerns. In this study, process intensification in hydrogen production from natural gas, coal- and biomass-derived syngas is investigated both experimentally and theoretically. A novel reactor/separator system, termed the “one-box” process is being employed. The heart of this system is a membrane reactor (MR) that combines the water-gas shift (WGS) reaction with hydrogen separation into a single unit, thus eliminating the need for the commonly utilized two separate WGS reactors and a distinct purification unit.; Impurity-resistant carbon molecular sieve (CMS) membranes and sour-gas shift catalysts are utilized in order to treat the gas streams with simulated coal/biomass-derived syngas compositions. Both have shown high tolerance for H2S and NH3, which are the main impurities in the syngas (in fact, the sour-gas shift catalysts require sulfur to be present in order to remain active). This adds another benefit to the system by eliminating the need for gas clean-up upstream of the WGS reactor, which saves energy, and significantly simplifies the process design. The CMS membrane stability is further investigated in the presence of model tar and organic vapor compounds. The membranes proved to be stable at temperatures akin to the WGS environment. Permeation loss occurred at lower temperatures; however, regeneration was readily achieved by purging the membranes with inert gas at higher temperatures. This indicates that at low temperatures only surface coverage through condensation occurs, with little or no irreversible pore plugging of the membrane.; The project focus has been on experimental investigations in order to prove the feasibility of using the ‘one-box’ system for H2 production and to validate a mathematical model developed for use for scale-up investigations. Prior to their use in the MR experiments, the membranes are characterized via single and multi-component gas permeation measurements. Packed-bed experiments are also performed in order to derive the kinetic rate expressions. The effect of different experimental conditions on MR performance, in terms of CO conversion, hydrogen product recovery and purity is experimentally studied, and the results are compared with those from the mathematical model. The model is further used for process scale-up, and in order predict the MR performance under conditions akin to the industrial applications. It is shown that the MR-based systems are capable of converting more CO into H2 when compared to the more traditional packed-bed reactors, in some cases attaining almost complete CO conversions.; In addition to the CMS membrane-based MR, we have also investigated palladium (Pd) membranes with infinite selectivity towards hydrogen, combined with low-temperature shift (LTS) catalysts are used for ultra pure hydrogen production from gas streams with simulated natural gas reformate compositions, to serve as a feed for fuel cell applications. One key advantage of using the Pd membranes is that one can produce a high-purity (> 99.9%) hydrogen product for fuel cell applications. |
| Keyword | hydrogen production; membrane reactor; water-gas shift reaction; carbon membrane; palladium membrane |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m3883 |
| Rights | Abdollahi, Mitra |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Abdollahi-4476 |
| Archival file | uscthesesreloadpub_Volume29/etd-Abdollahi-4476.pdf |
Description
| Title | Page 1 |
| Full text | AN INTEGRATED ‘ONE-BOX’ PROCESS FOR HYDROGEN PRODUCTION by Mitra Abdollahi A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (CHEMICAL ENGINEERING) May 2011 Copyright 2011 Mitra Abdollahi |
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