Battelle Pacific Northwest Division (Battelle), Fluor Corporation, and Queen’s University have teamed together to develop a new CO2 capture technology for treating post-combustion power plant emissions. This new process couples the unique attributes of non-aqueous, switchable organic solvents (CO2-binding organic liquids; CO2BOLs) with the newly discovered polarity-swing-assisted regeneration (PSAR) process. The process requires significantly lower temperatures and energies for CO2 separation relative to conventional technology, making appreciable cost savings possible. Combining the PSAR with CO2BOLs is estimated to provide more than 42 percent energy savings over aqueous alkanolamine systems. Further, the low regeneration temperatures of the proposed technology allow a unique energy integration method that can reduce overall process parasitic energy requirements by more than 65 percent compared to commercial systems. An important characteristic of the PSAR process is that it efficiently utilizes heat from the power plant, rather than steam, to operate the CO2 capture process. This not only improves the efficiency of the overall process but also simplifies the use of this process as a retrofit to an existing pulverized coal power plant.
The process will be further defined using Aspen Plus™ software to develop process flow diagrams and heat and material balances. Laboratory experiments will be conducted to gather process chemistry information as inputs to the flow sheet models and economic assessment. Preliminary equipment sizing will be performed to enable a capital cost estimate and the flow sheet models will be used to gather operating cost information. The process definition, laboratory measurements, and economic information will be reviewed before committing to bench-scale testing. An existing Battelle bench-scale solvent testing system will be retrofitted to serve as the bench-scale system for the CO2BOLs/PSAR process. Bench-scale testing information will be gathered and an environmental, health, and safety (EH&S) evaluation will be performed.
The mission of the U.S. Department of Energy/National Energy Technology Laboratory (DOE/NETL) Carbon Capture Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation’s vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The Carbon Capture R&D Program portfolio of carbon dioxide (CO2) emissions control technologies and CO2 compression is focused on advancing technological options for new and existing coalfired power plants in the event of carbon constraints.
Pulverized coal (PC) plants burn coal in air to produce steam and comprise 99 percent of all coal-fired power plants in the United States. Carbon dioxide is exhausted in the flue gas at atmospheric pressure and a concentration of 10 to 15 percent by volume. Post-combustion separation and capture of CO2 is a challenging application due to the low pressure and dilute concentration of CO2 in the waste stream, trace impurities in the flue gas that affect removal processes, and the parasitic energy cost associated with the capture and compression of CO2. Solvent-based CO2 capture involves chemical or physical sorption of CO2 from flue gas into a liquid carrier. Although solvent-based systems are used commercially to remove CO2 from industrial gases, they have not been applied to the removal of large volumes from coal-fired power plant flue gas due to significant cost and efficiency penalties. The use of non-aqueous solvents is an area of research that has the potential to effectively reduce the energy requirements for regeneration and reuse of the solvent.
The combination of CO2BOL solvents with the PSAR process has the potential to significantly reduce the cost of capturing CO2 from coal-fired power plants and make progress toward achieving at least 90 percent capture of CO2 with less than 35 percent increase in the cost of electricity. This unique approach will be applicable to both new construction of pulverized-coal power plants as well as the retrofit of existing facilities.
Primary Project Goal
The overall project goal is to further develop and evaluate a new carbon capture process combining CO2BOLs with PSAR to achieve the DOE goals for post-combustion CO2 capture.
The objectives of the 30-month project are to complete technical and economic evaluations, integrated bench-scale process testing, safety and health assessments, and a final technology assessment.
Perform process definition including process design and flow sheet evaluation.
Perform process chemistry evaluations including kinetic and equilibrium measurements to enable equipment design.
Perform an initial techno-economic feasibility study using Aspen Plus™ modeling. The economic evaluation will include capital and consumable cost estimations.
Complete design of the bench-scale system retrofits, procurement of required equipment, and the actual retrofit of the bench-scale system.
Conduct shakedown and parametric testing on the bench-scale system.
Gather information from the bench-scale test measure-ments to conduct an EH&S analysis.
Revise the techno-economic evaluation of the technology and assess overall efficacy for further programmatic considerations.
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