Subscribe free to our newsletters via your
. 24/7 Space News .




CARBON WORLDS
Sequestration on shaky ground
by Staff Writers
Boston MA (SPX) Jan 26, 2015


Image courtesy Christine Daniloff and MIT.

Carbon sequestration promises to address greenhouse-gas emissions by capturing carbon dioxide from the atmosphere and injecting it deep below the Earth's surface, where it would permanently solidify into rock. The U.S. Environmental Protection Agency estimates that current carbon-sequestration technologies may eliminate up to 90 percent of carbon dioxide emissions from coal-fired power plants.

While such technologies may successfully remove greenhouse gases from the atmosphere, researchers in the Department of Earth, Atmospheric and Planetary Sciences at MIT have found that once injected into the ground, less carbon dioxide is converted to rock than previously imagined.

The team studied the chemical reactions between carbon dioxide and its surroundings once the gas is injected into the Earth -- finding that as carbon dioxide works its way underground, only a small fraction of the gas turns to rock. The remainder of the gas stays in a more tenuous form.

"If it turns into rock, it's stable and will remain there permanently," says postdoc Yossi Cohen. "However, if it stays in its gaseous or liquid phase, it remains mobile and it can possibly return back to the atmosphere."

Cohen and Daniel Rothman, a professor of geophysics in MIT's Department of Earth, Atmospheric, and Planetary Sciences, detail the results this week in the journal Proceedings of the Royal Society A.

Current geologic carbon-sequestration techniques aim to inject carbon dioxide into the subsurface some 7,000 feet below the Earth's surface, a depth equivalent to more than five Empire State Buildings stacked end-to-end. At such depths, carbon dioxide may be stored in deep-saline aquifers: large pockets of brine that can chemically react with carbon dioxide to solidify the gas.

Cohen and Rothman sought to model the chemical reactions that take place after carbon dioxide is injected into a briny, rocky environment. When carbon dioxide is pumped into the ground, it rushes into open pockets within rock, displacing any existing fluid, such as brine.

What remains are bubbles of carbon dioxide, along with carbon dioxide dissolved in water. The dissolved carbon dioxide takes the form of bicarbonate and carbonic acid, which create an acidic environment. To precipitate, or solidify into rock, carbon dioxide requires a basic environment, such as brine.

The researchers modeled the chemical reactions between two main regions: an acidic, low-pH region with a high concentration of carbon dioxide, and a higher-pH region filled with brine, or salty water. As each carbonate species reacts differently when diffusing or flowing through water, the researchers characterized each reaction, then worked each reaction into a reactive diffusion model -- a simulation of chemical reactions as carbon dioxide flows through a briny, rocky environment.

When the team analyzed the chemical reactions between regions rich in carbon dioxide and regions of brine, they found that the carbon dioxide solidifies -- but only at the interface. The reaction essentially creates a solid wall at the point where carbon dioxide meets brine, keeping the bulk of the carbon dioxide from reacting with the brine.

"This can basically close the channel, and no more material can move farther into the brine, because as soon as it touches the brine, it will become solid," Cohen says. "The expectation was that most of the carbon dioxide would become solid mineral. Our work suggests that significantly less will precipitate."

Cohen and Rothman point out that their theoretical predictions require experimental study to determine the magnitude of this effect.

"Experiments would help determine the kind of rock that would minimize this clogging phenomenon," Cohen says. "There are many factors, such as the porosity and connectivity between pores in rocks, that will determine if and when carbon dioxide mineralizes. Our study reveals new features of this problem that may help identify the optimal geologic formations for long-term sequestration"


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Massachusetts Institute of Technology
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





CARBON WORLDS
Graphene plasmons go ballistic
Barcelona, Spain (SPX) Jan 13, 2015
Squeezing light into tiny circuits and controlling its flow electrically is a holy grail that has become a realistic scenario thanks to the discovery of graphene. This tantalizing achievement is realized by exploiting so-called plasmons, in which electrons and light move together as one coherent wave. Plasmons guided by graphene -a two-dimensional sheet of carbon atoms - are remarkable as ... read more


CARBON WORLDS
Service Module of Chinese Probe Enters Lunar Orbit

Service module of China's lunar orbiter enters 127-minute orbit

Chinese spacecraft to return to moon's orbit

Russian Company Proposes to Build Lunar Base

CARBON WORLDS
Team Working on Strategy to Fix Flash Memory Issue

UA-led HiRISE camera spots long-lost space probe on Mars

Lost and found in space: Beagle 2 seen on Mars 11 years on

Crystal-Rich Rock 'Mojave' is Next Mars Drill Target

CARBON WORLDS
Tech barons paint rosy future at Davos despite security fears

U.S. food headed for ISS stalled in Russian customs

US venture capital funding near dot-com boom levels

Singer Sarah Brightman delays space tourist training

CARBON WORLDS
China launches the FY-2 08 meteorological satellite successfully

China's Long March puts satellite in orbit on 200th launch

Countdown to China's new space programs begins

China develops new rocket for manned moon mission: media

CARBON WORLDS
Russian Cargo Spacecraft to Supply ISS With Black Caviar

Astronauts' year-long mission will test limits

Astronauts prepare for year-long stay on space station

Astronauts take shelter after alarm at space station

CARBON WORLDS
Soyuz Installed at Baikonur, Expected to Launch Wednesday

Russian firm seals $1 billion deal to supply US rocket engines

SpaceX CEO Elon Musk wants to shake up satellite industry

Firefly Space Systems and NASA have Inked Space Act Agreement

CARBON WORLDS
Three nearly Earth-size planets found orbiting nearby star

Three-Planet System Holds Clues to Atmospheres of Earth-size Worlds

Meteorites weren't exactly the building blocks of young planets

A twist on planetary origins

CARBON WORLDS
Laser-generated surface structures create extremely water-repellent metals

New laser-patterning technique turns metals into supermaterials

Satellite telemetry tracks bearded vultures

Japan researchers target 3D-printed body parts




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.