Evaluation of Calcium Looping as Carbon Capture Option for Combustion and Gasification Power Plants

Power generation is one of the industrial sectors with major contribution to greenhouse gas emissions (especially CO2). For climate change mitigation, a special attention is given to the reduction of CO2 emissions by applying capture and storage techniques in which CO2 is captured from energy-intensive processes and then stored in suitable safe geologic locations. Carbon capture and storage (CCS) technologies are expected to play a significant role in the coming decades for curbing the greenhouse gas emissions and to ensure a sustainable development of power generation and other energy-intensive industrial sectors (e.g. cement, metallurgy, petro-chemical etc.). Among various carbon capture options, chemical looping systems are very promising options for intrinsically capture CO2 with lower cost and energy penalties. This paper evaluates calcium looping process as a promising carbon capture option to be applied in the most important coal- based power generation technologies. Combustion technology (Pulverized Fuel - PF) operated in both sub-critical and super- critical steam conditions were evaluated. Also, the gasification technology using an oxygen-blown entrained-flow gasifier was evaluated. As benchmark options, the same power generation technologies were evaluated without CCS. The power plant case studies investigated in the paper produces around 545 – 560 MW net power with at least 90% carbon capture rate. The modeling and simulation of the whole power generation schemes produced the input data for quantitative technical and environmental evaluations of power plants with carbon capture (similar power plant concept without CCS was used as reference for comparison). Mass and energy integration tools were used to assess the integration aspects of calcium looping unit into the whole power plant design, to optimize the overall efficiency and to evaluate the main sources of energy penalty for carbon capture.