In the processes for extracting carbon dioxide that exist in the prior art, there are essentially three types of process: 1. gas scrubbing process, 2. adsorption process and 3. membrane process. In the washing process, so-called amine washing is widespread in which in aqueous solutions containing monetholamine or its derivatives are used, which act as acceptor for carbon dioxide. Desorption is achieved by increasing the temperature of the acceptor solution to 120 ° C. During the process, a small part of the monetholamine escapes. Another aqueous process is pressure swing scrubbing. For this purpose, the entire gas flow must be compressed to 4 - 6 bar while mixing with water. The carbon dioxide dissolved in water is then desorbed by applying a negative pressure. In the adsorption process, carbon dioxide is adsorbed onto solids. For regeneration, these must be heated, which is also done under vacuum. Gas separation membranes are used in the membrane process. A retention of carbon dioxide can be achieved under high pressure. However, it is only possible to obtain pure gases with this process with further process effort. What the processes have in common is that enormous energy losses occur as a result of the fact that a large part of the required energy is lost in the form of thermal energy or pressure energy.
A process was developed in which a physiological amino acid is used to electrostatically bind the water-soluble form of carbon dioxide (carbonate anions). This reaction takes place spontaneously at temperatures between 0 and 99 ° C. This makes it possible to bind more than 120g / carbon dioxide in one liter of the aqueous acceptor solution without pressure and to transport it therein. Following the binding, selective release can take place in an electrodialysis device. The carbonate anions are transported electrophoretically through a membrane suitable for selective material transport. After passing through the membrane, the carbonate anions are bound in an aqueous transport medium and passed outside the electrodialysis unit into an outgassing unit, where outgassing occurs spontaneously in the form of carbon dioxide. The acceptor liquid is regenerated while passing through the electrodialysis unit and can be used again for the extraction of carbon dioxide.
This method and the way in which the method is carried out result in significant advantages compared to the methods presented from the prior art. The process has no ecological concern and is carried out with a physiologically occurring compound that is made from renewable raw materials. There is no loss of this compound, as could be shown in long-term operation. The extraction of carbon dioxide can take place with a gas scrubber available in the prior art and is therefore scalable as required. The carbon dioxide dissolved in the form of carbonate anions is separated electrokinetically, so that the energy input is used almost exclusively for the separation. This enables an energy efficiency of > 80% to be achieved. As a by-product of the energy input, pure gases from hydrogen and oxygen, which are created in the electrolyte chambers by electrolysis, are obtained. Due to the selective transport of carbon anions by means of the method, a pure gas of carbon dioxide is immediately available.