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Sequestration

They did it to OJ's jury; Pauli Shaw made a movie about it. Sequestration is locking something away. In the case of juries it is to protect the jurors from external influences. With CO₂ we wish to lock it away so it does not enter the atmosphere and contribute to climate change (possibly). So all we need is a location where high volumes of CO₂ can be stored, trivial right?

There are not too many locations where there are massive holes in the ground but there are other options:

• In the ocean
• In minerals
• In depleted oil and gas wells
• In brine fields
• In coal fields (unminable)
• In carbon Sinks

Source:JPM Flue gas: Nitrogen is blue, water is red with two white hydrogen atoms attached, carbon dioxide is grey with two purple spheres attached, there is some oxygen too. The where is Waldo question? Can you spot the single S atom (yellow)?

Most will be used in the US where appropriate. However, there is a significant and costly catch: we do not get pure carbon dioxide out of the stack of power plants! What goes in: Fuel and air. What comes out: products of combustion and air. The products of combustion are mostly carbon dioxide and water with lesser quantities of NO_x and sulphur dioxide etc. The air that we used is were the problem is. Air is mostly nitrogen. We want the oxygen but have to let the nitrogen tag along unless we can afford to separate them ($$$$$$). For every 1 mole of oxygen we get about 6 moles of nitrogen. We also add more air than is necessary to help the mixing process, necessary for combustion to take place. So the nitrogen that goes into the system come out again and we will have to separate the carbon dioxide from the other gases, oxygen (from the excess air), water (product of combustion) and nitrogen ($$$$$$). In the flue gas image shown to the right, the molecules are shown very close together in an unrealistic representation (too high a density) for viewability.

We have the technology (6 Million Dollar man reference for those too young to have picked it up), but part of the cost of sequestration will be this separation process. If we did not separate the gases we will have to pay more for the compression and transportation and pumping ($$$$$$).