Pilot unit in the practice
Removal is firstly undertaken of the nitrogen, dust and sulphur in the flue gases which arise from coal combustion. But the flue gas still has minor concentrations of CO2 (approx. 13% by volume). Post-combustion capture (PCC) sees to it that the carbon dioxide with the help of scrubbing solutions (amines or other sorbents) is dissolved from the flue gas and chemically bound (with an absorbent). In a second step, it is dissolved once again from the absorbent, concentrated and then stored.
Even at the start of the 1990s, Hitachi, Ltd. in Japan was carrying out tests on a small-scale flue gas scrubber plant. Hitachi Power Europe has taken up these findings and developed a mobile CO2 capturing pilot unit which is being tested at a number of power plant sites of energy suppliers E.ON and Electrabel in Germany, the Netherlands and Belgium.
The pilot unit not only has the benefit of being mobile and can thus be deployed under various conditions but it is also not bound to any specific scrubbing/amine solution. The operator is free to use the means which he finds the most suitable. As soon as commercial use is a possibility, the process can also be retrofitted into existing power plants.