Carbon Dioxide Capture Using Advanced Carbon Sorbents

The immediate application of this technology is to capture 90% CO₂ from the flue gas of a pulverized coal fired power plant at no more than a 35% increase in cost of electricity The technology was tested on a large bench scale level in a coal-fired steam bolier  In the bench-scale tests, we achieved  a capture efficiency of 98% with the CO₂ purity of >97%.  The proposed process is based on two unique components: carbon sorbent  microspheres made by ATMI and a novel reactor configuration developed by SRI.  The carbon sorbent has a high CO₂ capacity, rapid adsorption and desorption rates, low heat requirements, extremely low attrition resistant, and high hydrothermal stability.  An integrated adsorber-stripper reactor system developed at SRI allows the sorbent  microspheres to move, by gravity, from the adsorber to the stripper.  The integrated system, based on a cascading bed geometry, enables the integration of adsorption and stripping of the CO2 in a single vertical column.  Adsorption is performed at about 30 degrees Celsius while the desorption is accomplished using low pressure steam at about 100 degrees Celsius.  The microspheres, after cooling, are cycled back to the adsorber.  The integrated reactor allows a low pressure drop for the passage of the flue gas streams and direct contact with steam for efficient heat transfer during stripping.  The integrated system has been tested for 7000 cycles with excellent stability.  The process will be tested, in the future, using a slip stream from an operating PC-fired boiler.