Portfolio 6

The amount of carbon dioxide (CO2) in the atmostphere has  greatly increased over time. Evidence shows that CO2, which is capable of trapping heat, has caused the global temperature to rise. If this situation continues, several disaster could happen. However, it's not easy to cut down the amount of CO2 entering the atmosphere. Burning fossil fuels releases huge amount of CO2, but they cannot be easily substituted. As the greatest fossil fuel supply, coal emits the greatest amount of CO2 per unit energy produced. A chemical system to capture CO2 has been used at some industries. This approach can be adapted for coal-based power plants, where smokestacks is replaced with absorption towers, one of which to isolate and absorp CO2 from the other gases, and another to seperate the CO2 from the first tower, so as the chemical can then be reused. Another variation of this approach is to alter the combustion process by burning coal in oxygen. This makes seperating the CO2 from the exhaust easier. However, another problem, which is the need for oxygen, emerges. If this process can be made economical, the cost of CO2 capture can be reduced. Advanced method to generate power from coal also provides a way to capture CO2. In coal-gastification units, burning of coal produces a synthetic gas, which can be converted to other useful gas. Several underground places investigated, such as old gas and oil fields. However, these fields do not have the capacity to store the great amount of CO2. Thus, sedimentary rocks formation might be another prossible way to store CO2. However, although redimentary rocks are highly available, it's unsure whether they can be used safely, as several problems might caused CO2 leakage. Some experts suggests injecting the CO2 into sediments beneath the ocean floor. Although this approach might be a little bit costly, but it's safer. Althought several concern exists, but it's highly possible that these technology will succeed.

References:

National Acedemy of Engineering. (n.d.). Develop carbon sequestration methods. Retrived November 3, 2008, from http://www.engineeringchallenges.org/cms/8996/9077.aspx.