Coal and natural gas represent the bulk of energy supplies in the US. Even in the control of pollution, the burning of these fossil fuels for energy emit large amounts of carbon dioxide into the atmosphere. Research uses microcapsule technology that can make carbon dioxide capture cheaper, safer and more efficient.
Although the use of renewable energy is increasing, coal and natural gas still represent the bulk of energy supplies in the United States. Even in the control of pollution, the burning of these fossil fuels for energy emitted a huge amount of carbon dioxide into the atmosphere – only in the United States coal and natural gas contributed to 1,713 million metric tons of CO2, or 98% of all CO2 emissions from the electricity sector in 2017.1 In an effort to mitigate these impacts, researchers are looking for affordable ways to capture carbon dioxide from exhaust fumes in power stations.
Research conducted by the University of Pittsburgh and the Lawrence Livermore National Laboratory (LLNL) use microcapsule technology that can make carbon dioxide capture cheaper, safer and more efficient.
"Our approach is very different from the traditional method of capturing carbon dioxide in a power plant," said Katherine Hornbostel, a mechanical engineering assistant at the Pitt Engineering School in Swanson. "Instead of leaching a chemical solvent down the tower (like water down the waterfall), put the solvent in miniature microcapsules."
Similar to the liquid drug content in a pill, microencapsulation is a process in which liquids are surrounded by a solid coating.
"In our proposed carbon capture reactor design, we pack a pile of microcapsules into a container and exhaust stream of the power plant through that," said Hornbosse. "The heat required for conventional reactors is high, resulting in higher operating costs for the plant, and our design will be less structured and will require less power to operate, thereby reducing costs. "
Conventional designs also use a heavy amine solvent that is expensive and can be dangerous for the environment. The microcapsule project, created by Hornbostel and her associates in the LLNL, uses a solution that is made from a simple household item.
"We use soda to dissolve dissolved in water as our solvent," said Hornbosse. "This is cheaper, better for the environment and richer than conventional solvents. Costs and abundance are critical factors when it comes to 20 or more meters of reactors installed on hundreds of power plants."
Hornbostel explained that the small size of the microcapsule gives the solvent a large area for a given volume. This high surface makes the solvent absorb faster carbon dioxide, which means that more slowly absorbing solvents can be used. "It's good news," Hornbosse says, "because it gives cheaper solvents like soda to compete with more expensive and corrosive solvents."
"Our microcapsule technology and design offer a promise to capture carbon after burning because they help to make more efficient slow-acting solvents," Hornbosse said. "We believe that reduced solvent costs, combined with a smaller structure and lower operating costs, can help coal and natural gas power stations to sustain long-term profits without damaging the environment."
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