Clean Hydrogen Production and Carbon dioxide Capture Methods

Authors

Sushant KumarFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Materials Science and Engineering

First Advisor's Name

Surendra K. Saxena

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Arvind Agarwal

Third Advisor's Name

Jiuhua Chen

Fourth Advisor's Name

Chunlei Wang

Fifth Advisor's Name

Krish Jayachandran

Keywords

Fossil fuels, global warming, steam methane reformation, coal gasification, hydrogen, carbon dioxide capture, energy penalty, hydrogen storage, hydrides

Date of Defense

10-1-2013

Abstract

Fossil fuels constitute a significant fraction of the world’s energy demand. The burning of fossil fuels emits huge amounts of carbon dioxide into the atmosphere. Therefore, the limited availability of fossil fuel resources and the environmental impact of their use require a change to alternative energy sources or carriers (such as hydrogen) in the foreseeable future. The development of methods to mitigate carbon dioxide emission into the atmosphere is equally important. Hence, extensive research has been carried out on the development of cost-effective technologies for carbon dioxide capture and techniques to establish hydrogen economy.

Hydrogen is a clean energy fuel with a very high specific energy content of about 120MJ/kg and an energy density of 10Wh/kg. However, its potential is limited by the lack of environment-friendly production methods and a suitable storage medium. Conventional hydrogen production methods such as Steam-methane-reformation and Coal-gasification were modified by the inclusion of NaOH. The modified methods are thermodynamically more favorable and can be regarded as near-zero emission production routes. Further, suitable catalysts were employed to accelerate the proposed NaOH-assisted reactions and a relation between reaction yield and catalyst size has been established. A 1:1:1 molar mixture of LiAlH₄, NaNH₂ and MgH₂ were investigated as a potential hydrogen storage medium. The hydrogen desorption mechanism was explored using in-situ XRD and Raman Spectroscopy.

Mesoporous metal oxides were assessed for CO₂ capture at both power and non-power sectors. A 96.96% of mesoporous MgO (325 mesh size, surface area = 95.08 ± 1.5 m²/g) was converted to MgCO₃ at 350°C and 10 bars CO₂. But the absorption capacity of 1h ball milled zinc oxide was low, 0.198 gCO₂ /gZnO at 75°C and 10 bars CO₂. Interestingly, 57% mass conversion of Fe and Fe₃O₄ mixture to FeCO₃ was observed at 200°C and 10 bars CO₂. MgO, ZnO and Fe₃O₄ could be completely regenerated at 550°C, 250°C and 350°C respectively. Furthermore, the possible retrofit of MgO and a mixture of Fe and Fe₃O₄ to a 300 MWe coal-fired power plant and iron making industry were also evaluated.

Identifier

FI13120609

Recommended Citation

Kumar, Sushant, "Clean Hydrogen Production and Carbon dioxide Capture Methods" (2013). FIU Electronic Theses and Dissertations. 1039.
https://digitalcommons.fiu.edu/etd/1039