Most of the electricity that we still make use of comes from coal-fired power plants, which are nowhere as green as the world wants them to be. While a shift to renewable energy sources such as the sun and the wind is essential for a cleaner world of tomorrow, research also has to be carried out to figure out ways coal can be used to produce energy, without emitting tons of harmful CO2 in the process. A research team at the Ohio State University has done exactly that by coming up with a technology to harness the energy of coal without polluting the environment.
The technology, dubbed Coal Direct Chemical Looping, chemically harnesses coal’s energy and efficiently contains the carbon dioxide produced by the reaction, before it can be released into the atmosphere. The technology, which is being claimed to contain as much as 99 percent of the CO2 released during the reaction, makes use of coal that’s been ground into a powder and iron oxide beads that are much larger than the coal particles.
The mix is heated to high temperatures in a chamber where the materials react with each other. Carbon from coal binds with oxygen from the iron oxide and creates CO2, which rises into a chamber where it is captured and what’s left behind is coal ash and hot iron. Hot iron beads, which are significantly larger than the coal ash are easily separated from the mix and delivered to a chamber where the heat energy is harnessed to produce electricity. The separated carbon dioxide can then be sequestered for storage and once cooled, the iron beads can be reused almost indefinitely.
To prove their technology, the research team has operated a prototype system making use of the technology for 203 continuous hours, while capturing 99 percent of the CO2 produced in the reaction. Now, the researchers are about to take their technology to the next level by building a large-scale pilot plant which is under construction at the US Department of Energy’s National Carbon Capture Center. The plant is set to being operations later this year and will be producing about 250 thermal kilowatts of power.