Carbon sequestration

CO2 sequestration is the capture, extraction, separation, collection, etc, of carbon dioxide and a means for its storage or use.

See main article on carbon capture and storage for information on large scale permanent sequestration and/or storage of industrially-produced CO2 into deep saline aquifers, which is proposed as a means of mitigating the accumulation of green houses gases in the atmosphere from fossil fuel burning.

Methods of CO2 sequestration include:

• Adsorption

www.netl.doe.gov (PDF file)

• Amine extraction
• Metal-organic frameworks (MOF's) [1] [2]
• Mineral storage

Calcium oxide: Carbon Dioxide reacts with quicklime (calcium oxide), to form limestone (calcium carbonate). [3]

Serpentine: The metamorphic mineral serpentine (magnesium silicate hydroxide), is composed of magnesium, silicon and oxygen.

Ovivine: [4] [5]

• Molecular Sieve
• Polymer membrane gas separators [6] [7]
• Porous carbon
• Reversing heat exchangers

• Regenerative Carbon Dioxide Removal System (RCRS)

The RCRS on the space shuttle Orbiter uses a two-bed system that provides continuous removal of CO2 without expendable products. Regenerable systems allow a shuttle mission a longer stay in space without having to replenish its sorbent canisters. Older lithium hydroxide (LiOH)-based systems, which are non-regenerable, are being replaced by regenerable metal-oxide-based systems. A metal-oxide-based system primarily consists of a metal oxide sorbent canister and a regenerator assembly. This system works by removing carbon dioxide using a sorbent material and then regenerating the sorbent material. The metal-oxide sorbent is regenerated by pumping air heated to around 400°F at 7.5 scfm through its canister for 10 hours. [8]

www.osti.gov the capture, utilization and disposal of carbon dioxide from fossil fuel-fired power plants(pdf)

Recycling sequestered CO₂

It has recently been noted that the CO₂ from fossil fuel emissions is almost entirely depleted in radiocarbon, or ¹⁴C, and therefore could be used to produce food products containing little or no radiocarbon. Persons raised on such low radiocarbon food could be spared billions of lifetime chromosomal damage events, which could reduce rates of spontaneous cancer or birth defects, or even slow the aging process. This could increase incentives for carbon sequestration in general, and particularly in those methods which would allow the subsequent recovery and reuse of low radiocarbon CO₂ for producing safer food.

News on CO2 Sequestration

• Sieves put a lid on greenhouse gas

• On Friday, February 9, 2007 Sir Richard Branson offered a $25 million prize to anyone who develops a workable means to remove a billion tonnes of carbon dioxide per year from the atmosphere Note: Branson has little to lose, since his "billion" is measured in the UK sense of ten to the twelfth power, as compared with what he would call a "billard" and most of the world calls a "billion" in the sense of ten to the ninth power.