Graduate Thesis Or Dissertation

 

Hydrogen production via a sulfur-sulfur thermochemical water-splitting cycle Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/kh04ds34t

Descriptions

Attribute NameValues
Creator
Abstract
  • 4I₂(l)+4SO₂(l)+8H₂O(l)↔4H₂SO₄(l)+ 8HI(l)
  • 3H₂SO₄(g)↔ 3H₂O(g)+3SO₂(g)+1½O₂(g)
  • The critical step in the Sulfur-Sulfur cycle is the steam reformation of H₂S. This highly endothermic step is shown to successfully occur at temperatures in excess of 800˚C in the presence of a molybdenum catalyst. A parametric study varying the H₂O:H₂S ratio, temperature, and residence time in a simple tubular quartz reactor was carried out and Arrhenius parameters were estimated. All reactive steps of the Sulfur-Sulfur cycle have been either demonstrated previously or demonstrated in this work. A theoretical heat-to-hydrogen thermal efficiency is estimated to be 55% at a hot temperature of 1100 K and 59% at 2000 K. As a highly efficient, all-fluid based thermochemical cycle, the Sulfur-Sulfur cycle has great potential for feasible process implementation for the transformation of high quality heat to chemical energy.
  • 8HI(l)+H₂SO₄(l)↔ H₂S(g)+4H₂O(l)+4I₂(l)
  • H₂S(g)+2H₂O(g)↔ SO₂(g)+3H₂(g)
  • Thermochemical water splitting cycles have been conceptualized and researched for over half a century, yet to this day none are commercially viable. The heavily studied Sulfur-Iodine cycle has been stalled in the early development stage due to a difficult HI-H₂O separation step and material compatibility issues. In an effort to avoid the azeotropic HI-H₂O mixture, an imidazolium-based ionic liquid was used as a reaction medium instead of water. Ionic liquids were selected based on their high solubility for SO₂, I₂, and tunable miscibility with water. The initial low temperature step of the Sulfur-Iodine cycle was successfully carried out in ionic liquid reaction medium. Kinetics of the reaction were investigated by I₂ colorimetry. The reaction also evolved H₂S gas, which led to the conceptual idea of a new Sulfur-Sulfur thermochemical cycle, shown below:
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Keyword
Subject
Rights Statement
Peer Reviewed
Language
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2011-11-18T22:28:08Z (GMT). No. of bitstreams: 3 license_rdf: 19977 bytes, checksum: 9b906c3236d4c21f75a26a164fe0d6f3 (MD5) license_text: 23115 bytes, checksum: ec3783401c55aba9b2c045380c0dd4b3 (MD5) AuYeungNicholasJ2011.pdf: 2520045 bytes, checksum: 52e184e62b774a17a61e877c761e04af (MD5) Previous issue date: 2011-10-14
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2011-11-18T21:24:20Z (GMT) No. of bitstreams: 3 license_rdf: 19977 bytes, checksum: 9b906c3236d4c21f75a26a164fe0d6f3 (MD5) license_text: 23115 bytes, checksum: ec3783401c55aba9b2c045380c0dd4b3 (MD5) AuYeungNicholasJ2011.pdf: 2520045 bytes, checksum: 52e184e62b774a17a61e877c761e04af (MD5)
  • description.provenance : Approved for entry into archive by Laura Wilson(laura.wilson@oregonstate.edu) on 2011-11-18T22:28:08Z (GMT) No. of bitstreams: 3 license_rdf: 19977 bytes, checksum: 9b906c3236d4c21f75a26a164fe0d6f3 (MD5) license_text: 23115 bytes, checksum: ec3783401c55aba9b2c045380c0dd4b3 (MD5) AuYeungNicholasJ2011.pdf: 2520045 bytes, checksum: 52e184e62b774a17a61e877c761e04af (MD5)
  • description.provenance : Submitted by Nicholas Au Yeung (auyeungn@onid.orst.edu) on 2011-11-17T22:40:15Z No. of bitstreams: 3 AuYeungNicholasJ2011.pdf: 2520045 bytes, checksum: 52e184e62b774a17a61e877c761e04af (MD5) license_rdf: 19977 bytes, checksum: 9b906c3236d4c21f75a26a164fe0d6f3 (MD5) license_text: 23115 bytes, checksum: ec3783401c55aba9b2c045380c0dd4b3 (MD5)

Relationships

Parents:

This work has no parents.

Items