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OFFICE OF THE UNDER SECRETARY. CO 2 : From Coal to Light. April 28, 2009 Mark Handschy, U.S. Department of Energy. U. S. energy use . U. S. energy use . Coal generation. Coal generation…. Efficiency: η < 1 – T C / T H. T C = 373 °C. Carbon capture. Carbon sequestration.
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OFFICE OF THE UNDER SECRETARY CO2: From Coal to Light April 28, 2009 Mark Handschy, U.S. Department of Energy
Coal generation… Efficiency: η < 1 – TC/TH TC = 373 °C
Carbon capture CO2 is dilute and low-pressure
Carbon capture (2): coal gasification C (coal) + O2 + H2O → H2 + CO syngas CO+H2O → H2 + CO2 (water gas shift reaction)
Integrated gasification combined cycle (IGCC) high-pressure, concentrated CO2 Sulfur Raw Syngas H2 30% CO 40% CO2 10% Shifted Syngas H2 55% CO 1% CO2 39% H2O Sulfur Recovery Steam Gasifier 800 Psig Coal 2-Stage Selexol Unit Syngas Cooling Water Gas Shift PM Removal 105oF 700 Psia O2 CO2 70oF 25 Psia Fuel Gas 70oF 695 Psia Syngas Recycle ASU Combined Cycle Power Island CO2 Comp. Power CO2 105oF 2,200Psia Flue Gas water
IGCC efficiency • reduce emitted CO2 by increasing plant efficiency • capture CO2 and sequester • reduce parasitic loss by selecting amenable process gas turbines much hotter than steam turbines
Cumulative R&D impact Efficiency Improves Nearly 24 points