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Propositions of Sustainable methods of Carbon Dioxide Separation and Disposal. Caleb Stewart Mir-Akbar Hessami Department of Mechanical Engineering, Monash University, Clayton, Victoria, Australia. Introduction . What is the importance of developing sustainable technologies?
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Propositions of Sustainable methods of Carbon Dioxide Separation and Disposal Caleb Stewart Mir-Akbar Hessami Department of Mechanical Engineering, Monash University, Clayton, Victoria, Australia
Introduction • What is the importance of developing sustainable technologies? • Reduce greenhouse gas emissions (GHGE). • Kyoto Protocol required Australia to slow growth of annual GHGE to 108% of 1990 levels by the commitment period 2008-2012. • What is the Australian Government’s view on the Kyoto Protocol?
Australia is dependant on high carbon intensive energy production. • Coal mining accounts for approximately 1.9% of GDP [2]. • Australian Government declined to ratify the protocol.
Carbon Dioxide Separation Options • MEA Scrubbing – solvent strips CO2 from flue gas. • Membrane Technology – CO2 molecules are forced through a membrane. • Molecular Sieve – CO2 molecules are adsorbed to a sieve structure. • Desiccant Technology – CO2 is adsorbed at a specific temperature.
Carbon Dioxide Disposal Options • Geologic Injection – retention time 1000’s of years (Enhanced Oil Recovery, Coal Seams). • Oceanic Injection – retention time 100’s of years. • Oceanic Fertilisation – Nutrient released in to the ocean stimulate growth of photosynthetic organisms.
The photo-bioreactor approach • Use photo-synthetic organisms to fix carbon dioxide from atmosphere (table 3). • Select on the basis of • carbon uptake rate • light requirement • robustness to temperature fluctuations and; • by-products such as hydrogen or biomass.
The Design of a Photo-bioreactor • The design of a solar light delivery system to the photo-bioreactor installation consists of 3 components: • Distribution • Transmission • Solar Collection Solar Light DISTRIBUTION Tapered Glass Plate COLLECTION Parabolic Cylindrical Dish TRANSMISSION Fibre Optics
Distribution • Light requirements for the organisms used. • Specifications of the distribution plate. • Specifications of the bioreactor. • Specifications of the water bath. • Requirements for a sterile system.
Transmission • Maximum operating temperature. • Steady state maximum transmission capability. • Fibre Optic transmission losses ~ 10%. • Fibre optic dead losses ~ 40%. • Estimated number of fiber optics for the interface between distribution plate.
Collection • Available Energy • Daily irradiation levels • Useful visible light ~ 48% • Collection Efficiency ~ 95% • Overall efficiency ~ 24.6% • Required Collection Intensity and growth rates?
Conclusion • Most photo-bioreactor technology is not yet feasible on a large scale. • More research is required to identify photosynthetic micro-organisms capable of sequestering carbon on an economical scale.
References • Australian Greenhouse Office. Fact sheet 1 2002 National Greenhouse Gas Inventory, Canberra, Australia, www.ago.gov.au, April, 2004. • Mark R, Worral R., Greenhouse gas key performance indicators for Australian coal mines, CSIRO Exploration and Mining, Fifth International Conference on Greenhouse Gas Control Technologies Cairns Australia, 2000: 1020-1025.