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- 2011-11-15
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速度: 46'' 40'' 56'' 49'' 45''
越障: 8'49'' Topic: global warming caused by carbon dioxide (CO2) Scope: How to lower the atmospheric concentration of CO2? To discuss the techniques and their associated considerations
1. A big environmental issue is global warming, caused by increased atmospheric CO2. A lot of efforts have been aiming at reducing the CO2 emission. However, let's think it another way - how to take CO2 out of the atmosphere? In light of the natural process of photosynthesis, researchers have developed techniques to absorb the atmospheric CO2.
2. Three scientists (two from Columbia Univ, the other from Harvard?) simultaneously published their innovative techniques to absorb CO2. Details:.... the key technical consideration is how to control the CO2 absorption and release. In the method proposed by the 2nd scientist, this absorption/release regulation is triggered by temperature: low T ----> absorb CO2 high T ----> release CO2 According to the method by the 3rd scientist, the key is that the device absorbs CO2 and uses it as a reactant to carry on a chemical reaction....
3. Although the idea of taking out atmospheric CO2 is fancy, the techniques are pricy - it's like a million-dollar game. (detail: economic constraints... hardly affordable)
4. Based on the economic consideration, the key here is - how to utilize the CO2 absorbed? In order to implement this kind of techniques, we should look for demands for CO2. If the CO2 could be sold out as industrial raw materials, then Okay. Here is the answer: (1) mining factories have a demand for CO2. If the ground is exhausted, making the mining challenging, we can tap into the ground a huge volumn of CO2 gas so as to make digging easier. (a technique called EOR?) This is of economic benefit to the mining company, since in this case the company is absorbing CO2, rather than emitting CO2 (California has regulation on the amount of CO2 emission).
(2) CO2 can feed algea (藻类)
5. Since it's costly to take out CO2 from the air, how about take out CO2 directly from the chimney of factories/mining companies? It's a great idea, and it will cost about 1/10 of the cost for taking out CO2 from the air. This should be the future direction. |
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