1. Propositions of Sustainable methods of Carbon Dioxide Separation and Disposal Caleb Stewart Mir-Akbar Hessami Department of Mechanical Engineering, Monash University, Clayton, Victoria, Australia

2. 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?

3. 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.

4. Carbon Dioxide Separation Options MEA Scrubbing – solvent strips CO 2 from flue gas. Membrane Technology – CO 2 molecules are forced through a membrane. Molecular Sieve – CO2 molecules are adsorbed to a sieve structure. Desiccant Technology – CO 2 is adsorbed at a specific temperature.

5. 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.

6. 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.

7. The Design of a Photo-bioreactor The design of a solar light delivery system to the photo- bioreactor installation consists of 3 components: 1. Distribution 2. Transmission 3. Solar Collection Solar Light TRANSMISSION Fibre Optics DISTRIBUTION Tapered Glass Plate COLLECTION Parabolic Cylindrical Dish

8. 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.

9. 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.

10. Collection Available Energy Daily irradiation levels Useful visible light ~ 48% Collection Efficiency ~ 95% Overall efficiency ~ 24.6% Required Collection Intensity and growth rates?

13. 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.

14. References 1. Australian Greenhouse Office. Fact sheet 1 2002 National Greenhouse Gas Inventory, Canberra, Australia, www.ago.gov.au, April, 2004. www.ago.gov.au 2. 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.