Coal and natural gas account for most of the US energy supply. Even with contamination control, the burning of this fossil fuel into the atmosphere emits huge amounts of carbon dioxide. The research uses a microcapsule technology that can make carbon capture after burning cheaper, safer and more efficient.
Although the use of renewable energy is increasing, coal and natural gas still account for most of the United States' energy supply. Even with pollution control, the burning of these fossil fuels exposes a huge amount of carbon dioxide to the atmosphere – only US coal and natural gas alone have got 1713 million metric tons of CO2, or 98% of all CO2 the electricity sector in 2017.1 To mitigate this impact, researchers are looking for affordable ways to capture carbon dioxide from the exhaust gases from power plants.
Research by Pittsburgh and the Lawrence Livermore National Laboratory (LLNL) utilizes microcapsule technology that can make carbon capture after incineration cheaper, safer and more efficient.
"Our approach is very different from traditional carbon dioxide capture methods in a power plant," said Katherine Hornbostel, Master's Degree in Mechanical Engineering at Pitta Swanson Engineering School. "Instead of pouring a chemical solvent down the tower (for example, water down the waterfall), we place the solvent in tiny microcapsules."
Similar to the liquid tablet formulation, microcapsulation is a process in which the liquids are surrounded by a solid coating.
"In our proposed carbon capture reactor, we pack microcapsule bundles in a container and through their exhaust power outlets," Hornbostel said. "The heat demand for conventional reactors is high, which means higher operating costs. Our design will be smaller and will require fewer electricity, thus reducing costs."
Traditional designs also use a sharp amine solvent that is expensive and can be hazardous to the environment. Hornbostel and his collaborators use the solution derived from a common household object in a microcapsule design developed by LLNL.
"We use a water-soluble solution as our solvent," Hornbostel said. "It's cheaper, better for the environment and richer than conventional solvents. Cost and abundance are key factors when talking about hundreds of power plants installed in a reactor of 20 or more meters."
Hornbostel explained that the small size of the microcapsule gives the solvent a large surface area for a specific volume. This high surface area makes the solvent quick to absorb carbon dioxide, which means that slower absorbing solvents can be used. "This is a good news," says Hornbostel, "because it provides cheaper solvents, such as fine soda drinks, the ability to compete with more expensive and more corrosive solvents."
"Our proposed micro-capsule technology and design are promising for carbon capture after burning, because they help make the slow-acting solvents more effective," Hornbostel said. "We believe that reducing solvency costs, combined with a smaller structure and lower operating costs, can help coal and natural gas plants save profits in the long term without harming the environment."
Pittsburgh University. .