Speeding up Mother Nature's very own CO2 mitigation process

January 19, 2011

Speeding up Mother Nature's very own CO2 mitigation process

Enlarge

Courtesy of National Oceanic and Atmospheric Administration

(PhysOrg.com) -- Using seawater and calcium to remove carbon dioxide (CO2) in a natural gas power plant's flue stream, and then pumping the resulting calcium bicarbonate in the sea, could be beneficial to the oceans' marine life.

Greg Rau, senior scientist with the Institute of Marine Sciences at UC Santa Cruz and who also works in the Carbon Management Program at Lawrence Livermore National Laboratory, conducted a series of lab-scale experiments to find out if a seawater/mineral carbonate (limestone) gas scrubber would remove enough CO2 to be effective, and whether the resulting substance – dissolved calcium bicarbonate – could then be stored in the ocean where it might also benefit marine biota.

In addition to global warming effects, when carbon dioxide is released into atmosphere, a significant fraction is passively taken up by the ocean in a form that makes the ocean more acidic. This acidification has been shown to be harmful to marine life, especially corals and shellfish.

In his experiments, Rau found that the scrubber removed up to 97 percent of CO2 in a simulated flue gas stream, with a large fraction of the carbon ultimately converted to dissolved calcium bicarbonate.

At scale, the process would hydrate the carbon dioxide in power plant flue gas with water to produce a carbonic acid solution. This solution would then be reacted with limestone, neutralizing the carbon dioxide by converting it to calcium bicarbonate — and then would be released into the ocean. While this process occurs naturally (carbonate weathering), it is much less efficient, and at a much slower pace to be effective.

"The experiment in effect mimics and speeds up nature's own process," said Rau. "Given enough time, carbonate mineral (limestone) weathering will naturally consume most anthropogenic CO2. Why not speed this up where it's cost effective to do so?"

If the carbon dioxide reacted with crushed limestone and seawater, and the resulting solution was released to the ocean, this would not only sequester carbon from the atmosphere, but also would add to ocean alkalinity that would help buffer and offset the effects of ongoing marine acidification. Again, this speeds up the natural CO2 consumption and buffering process offered by carbonate weathering.

Earlier research has shown that ocean acidification can cause exoskeletal components to decay, retard growth and reproduction, reduce activity and even kill including coral reefs.

"This approach not only mitigates CO2, but also potentially treats the effects of acidification," Rau said. "Further research at larger scales and in more realistic settings is needed to prove these dual benefits."

Rau said the process would be most applicable for CO2 mitigation at coastal, natural gas-fired . Such plants frequently already use massive quantities of seawater for cooling, which could be cheaply reused for at least some of the CO2 mitigation process.

"This method allows a power plant to continue burning fossil fuel but eliminate at least some of the carbon dioxide that is emitted, and in a way that in some locations should be less expensive and more environmentally friendly than other sequestration methods" he said.

More information: The work, funded by the Energy Innovations Small Grant Program of the California Energy Commission and LLNL, appears in the journal Environmental Science & Technology.

Provided by Lawrence Livermore National Laboratory search and more info website

4.4 /5 (5 votes)  

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

Parsec
Jan 19, 2011

Rank: 5 / 5 (1)
As long as we don't have to blow the tops off mountains to mine the limestone... this sounds like a very cool approach.

One question remains however... is the calcium bicarb stable in the ocean over very long periods of time? Is it converted by geologic, chemical, or biochemical means to more obnoxious forms? For example, does the CO2 get released to the atmosphere after a few years or break back down into carbonic acid?
Caliban
Jan 20, 2011

Rank: not rated yet
I believe it provides the raw material for the formation of hard parts in aquatic organisms.
Howhot
Jan 20, 2011

Rank: 1 / 5 (1)
Interesting idea. A way to sequester CO2 and counteract ocean acidification. If we can just add oxygen to dead waters, it worth a trial. If somehow it can be made profitable then it will happen. Maybe via carbon credits?

Rank 4.4 /5 (5 votes)
Relevant PhysicsForums posts

More news stories

Australia hails surprise super-telescope decision

Australia has hailed a surprise decision giving it a role in a radio telescope project aimed at revolutionising astronomy, vowing to draw on its decades of experience in space science.

Space & Earth / Astronomy

created 8 hours ago | popularity 5 / 5 (2) | comments 0

Astronomers seize last chance in lifetime for Venus Transit

Astronomers are gearing for one the rarest events in the Solar System: an alignment of Earth, Venus and the Sun that will not be seen for another 105 years.

Space & Earth / Astronomy

created 8 hours ago | popularity 5 / 5 (1) | comments 0

SpaceX capsule has 'new car' smell, astronauts say

SpaceX's Dragon cargo vessel smells like a new car, said astronauts at the International Space Station after opening the hatches Saturday following the spacecraft's landmark mission to the orbiting lab.

Space & Earth / Space Exploration

created 8 hours ago | popularity 4.5 / 5 (11) | comments 0

Astronauts enter world's 1st private supply ship

(AP) -- Space station astronauts floated into the Dragon on Saturday, a day after its heralded arrival as the world's first commercial supply ship.

Space & Earth / Space Exploration

created 8 hours ago | popularity 5 / 5 (4) | comments 0

Dragon makes history with space station docking

The private company SpaceX made history Friday with the docking of its Dragon capsule to the International Space Station, the most impressive feat yet in turning routine spaceflight over to the commercial ...

Space & Earth / Space Exploration

created 23 hours ago | popularity 4.9 / 5 (9) | comments 0


SpotterRF debuts Radar Backpack Kit (w/ Video)

(Phys.org) -- SpotterRF has announced a special radar backpack kit designed to enhance situational awareness for soldiers on the ground. The company says its special radar is designed for warfighters as part ...

Thousands of shellfish found dead in Peru

Thousands of crustaceans were found dead off the coast of Lima following the mystery mass death of dolphins and pelicans, the Peruvian Navy said Friday.

Family history of Alzheimer's affects functional connectivity

(HealthDay) -- Cognitively normal individuals with a family history of late-onset Alzheimer's disease (AD) may display lower resting state functional connectivity in the default mode network (DMN) of the brain, ...

Transvaginal mesh op restores pelvic organ prolapse at price

(HealthDay) -- Transvaginal mesh (TVM) procedures are effective for anatomical restoration of pelvic organ prolapse (POP), but patients report a worsening of sexual function following surgery, according to ...

Travel to high altitudes tied to Crohn's, colitis flare-ups

(HealthDay) -- People with inflammatory bowel disease, which includes Crohn's disease and colitis, may be at increased risk for flare-ups when they fly or travel to high altitudes for skiing or mountain climbing, ...

It's in the genes: Research pinpoints how plants know when to flower

Scientists believe they've pinpointed the last crucial piece of the 80-year-old puzzle of how plants "know" when to flower.