Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Gerhard, Jason I.

Abstract

In the face of climate change, the world is looking to new fuel sources to meet the surging global energy demand. Hydrogen has been proposed as a promising energy vector being both a net-zero carbon emitter and having one of the highest gravimetric energy densities of known fuels. Production of hydrogen, however, is difficult with many of the technologies which exist today failing to be economically feasible or environmentally sustainable. Smouldering has recently been developed as a cost effective and energy efficient technology for destruction of organic wastes. The unique reaction zones created within a smouldering system have the potential to generate hydrogen if properly amended. For the first time, organic wastes were treated by an amended smouldering reaction to generate hydrogen in a carbon-neutral manner. Calcium Oxide (CaO) and steam were added to the smouldering system which completely treated woody biomass and coal tar while generating hydrogen. The maximum hydrogen concentration achieved in the smouldering system was 33.7% resulting in a net energy positive syngas. Evidence suggests that both heterogenous gasification and the water gas shift are the mechanisms of hydrogen formation. Results indicate that a smouldering reaction can be used simultaneously as both a waste management technology and a new method for producing hydrogen-rich syngas.

Summary for Lay Audience

Fossil fuels such as coal, oil and gas have been the predominant source of energy used for the past 150 years. Exploiting this resource has brought about many major advances in human civilization, industrializing our world as well as connecting it with transportation fuels and providing electricity from power plants. The primary means of extracting energy from fossil fuels involves burning them which releases CO2 and other greenhouse gases. Unfortunately, a legacy of burning fossil fuels has resulted in greenhouse gases slowly accumulating in the atmosphere. As their name suggests, these gases act much like a greenhouse reflecting heat energy back towards the surface of the earth causing warmer temperatures. Numerous studies have documented a warming climate causing extensive environmental damage both on land and at sea. As the main contributor to greenhouse gas emissions, the use of fossil fuels needs to be dramatically reduced and new sources of energy need to be used.

The modern world requires a tremendous amount of energy to sustain it making it extremely important to identify new sources of energy which can be green replacements for fossil fuels. Hydrogen is a gas which can also be used like a fossil fuel to generate energy except that it doesn’t produce any greenhouse gases. Hydrogen is difficult to manufacture effectively, though. STAR is a method of destroying many waste products which often cannot be treated by other technologies. Interestingly, the STAR process contains a reaction zone which could be conducive to generating hydrogen under the right conditions. This research explored, for the first time, amending the STAR process to not only destroy wastes, but also generate hydrogen. A low carbon intensity, waste-to-energy system was created as a new means to produce hydrogen.

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