A group of researchers from the Massachusetts Institute of Technology has developed a new method that allows you to extract carbon dioxide from any stream, whether it is air pumped by fans or the chimney outlet of a thermal power plant. The device created on the basis of this method is a specialized battery that absorbs carbon dioxide as it is charged and releases it in the form of a continuous stream of pure gas during discharge.
The new battery device consists of a series of sequential chambers in which there are electrochemical cells with small gaps between these cells through which the gas flow moves. The cell electrodes are coated with a complex composite material based on carbon nanotubes called polyanthraquinone.
When this battery is charged, an electrochemical reaction occurs on the surface of the electrodes. Since the electrode coating material was originally designed to absorb carbon dioxide, the molecules of this gas are attracted to the surface and held in this region. When the entire surface of the electrodes is completely filled with carbon dioxide molecules, the reverse process is required to clean the electrodes. Discharging this battery causes CO2 molecules to break away from the walls of the electrodes, after which clean gas can be pumped into a separate chamber.
The main advantage of this carbon dioxide absorption method is that this method is completely independent of the concentration of CO2 in the input stream. This battery works equally well, absorbing carbon dioxide from the atmosphere or from the exhaust of a car, where the concentration of CO2 approaches 100 percent.
Moreover, this technology allows scaling up to the point where the installation will be able to absorb all the carbon dioxide produced by a thermal power plant. For this, two identical installations will be required, one battery will be charged, absorbing carbon dioxide, and the second will be discharged, giving gas to a special container, from where it can be “packaged” into cylinders for use in welding technologies or pumped into a special underground storage.
The introduction of this technology will not only reduce carbon dioxide emissions into the atmosphere, but also produce large enough quantities of pure CO2, which is usually produced by special enterprises that consume energy for this, derived mainly from burning fuel or nuclear energy. By the way, about energy, scientists say that their method is quite economical, about one gigajoule of energy is required to produce one ton of carbon dioxide. Other methods used to produce pure carbon dioxide are more energy intensive, their “appetites” begin with 10 gigajoules per ton.
Laboratory tests conducted with the help of a prototype battery showed that this device is able to withstand without loss of its basic parameters 7 thousand charge-discharge cycles, after which the efficiency begins to decline to the level of 30 percent of the original. But further improvements to this technology, according to scientists, will create batteries that can withstand from 20 to 50 thousand cycles.