Siemens and E.ON have now placed a pilot carbon dioxide (CO2) capture plant into operation. Located at the Staudinger coal-fired power plant near Hanau, Germany, it is intended to verify the laboratory results and demonstrate through the end of 2010 that large-scale capture of CO2 from an existing power plant is possible. It will serve as the basis for larger demonstration plants. The advantage of the special CO2 scrubbing process from Siemens is that it is also suitable for backfitting. It consumes relatively little energy and does not pollute the environment.

An approximately 35 meter high absorber, through which a portion of the flue gas is passed, was erected next to Staudiger Unit 5. The cylinder contains metal sieves and a cleaning solution, through which the gas bubbles upward. The cleaning solution contains amino acid salts that are capable of binding CO2 and removing roughly 90 percent of it from the flue gas. The gas is then heated in an approximately 20 meter high desorber to dissolve it out of the salt. Nearly all of the salt can be reused and is perfectly safe for the environment.

All indications are that coal will remain an important source of energy for decades to come, with consumption projected to continue to increase, in particular in India and China. A technology that can significantly reduce the CO2 emissions of coal-fired power plants is therefore important for efficient climate protection. The gas captured during the post-combustion capture process can be compressed, used for chemical processes, or transported to storage facilities. Research is also currently being conducted into the underground storage of CO2.

Because CO2 capture consumes energy, it reduces the efficiency of the power plant. Heating of the cleaning agent, in particular, is energy-intensive. After years of optimization work in the laboratory, the experts at Siemens Energy have succeeded in improving the scrubbing process so that it only costs 9.2 percentage points of efficiency. The technology is a component of the Siemens environmental portfolio, with which the company generated €19 billion in sales in 2008. 
 
Reference Number: IN 2009.09.6e