(557d) High Temperature CO2 and Sulfur Removal Using Carbonation-Calcination Reaction (CCR) Process: Results From Computer Simulations and Experiments

Coal-fired power plants generate 50% of the nation’s electricity and account for one-third of the anthropogenic CO₂ emissions. Since it is widely anticipated that regulations on CO₂emissions will come into effect in the near future, coal-fired power plants, which are largepoint sources of CO₂, will be needed to adopt CO₂ reduction if the expected CO₂ levels are to be achieved. Several novel technologies are being pursued for this purpose.The Carbonation-Calcination Reaction (CCR) Process, which employs a calcium-based sorbent for CO₂ capture, is being developed at The Ohio State University (OSU). A 90% reduction in CO₂ and 100% SO₂ removal from coal-combustion flue gas, has been demonstrated using the CCR Process at 120 kWth scale. An intermediate reactivation step – hydration – has been integrated in the system to maintain the reactivity of the sorbent over multiple cycles.

Since the CCR Process removes CO₂ and SO₂ at high temperature, there are different process integration options for existing coal-fired power plants. Process analysis from computer simulations shows the CCR Process to be highly effective and efficient in removing both CO₂and SO₂ at low energy penalties under realistic conditions. The CCR Process is expected to maintain a constant electrical output with ~25-28% increase in thermal energy.

The feedstock for the CCR Process is naturally occurring limestone. The low-cost and abundance of the feedstock adds to the economic viability of the process. Six different naturally occurring calcium sorbents have been investigated at laboratory-scale over multiple carbonation-calcination-hydration cycles. Results from these tests confirm the suitability of the proposed high temperature steam hydration as a method for sorbent reactivation.