Project No: FC26-05NT42650
Performer: Southwest Research Institute
Shailesh D. Vora Technology Manager, Carbon Capture National Energy Technology Laboratory 626 Cochrans Mill Road P.O. Box 10940 Pittsburgh, PA 15236-0940 412-386-7515 firstname.lastname@example.org Travis Shultz Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-1370 email@example.com Jeffrey Moore Principal Investigator Southwest Research Institute 6220 Culebra Road San Antonio, Texas 78238 210-522-5812 firstname.lastname@example.org
DOE Share: $8,499,355.00
Performer Share: $3,469,148.00
Total Award Value: $11,968,503.00
Performer website: Southwest Research Institute - http://www.swri.org
Southwest Research Institute (SwRI), partnered with Dresser-Rand, is developing improved methods to compress CO2 to pipeline pressures while minimizing the energy expended. This project will design and evaluate an efficient and costeffective compressor for sequestering IGCC plant CO2. Various concepts will be investigated using fundamental thermodynamics and economics to determine if achieving the pressure rise is best accomplished through a liquid and/or gaseous CO2 state. Novel methods to compress gaseous CO2 while removing the heat of compression internal to the compressor will be investigated. The high pressure ratio required to compress CO2 from near atmospheric pressure to pipeline levels results in significant heat of compression. Less energy is required to boost the pressure of a cool gas; therefore, both upstream and interstage cooling is desirable. Researchers will determine the optimum compressor configuration and develop technologies for internal heat removal. Alternate compression options using liquefied CO2 and cryogenic pumping will be explored as well. This project consists of three phases. Phase I, Scoping and Modeling, focused on CO2 compressor/pump technologies and assessment of performance characteristics. Phase II, Bench-scale Testing and Evaluation, focused on evaluation and testing of selected CO2 compressor/pump technologies. Phase III, Pilot-Scale Testing, is focused on the scale-up and testing of a fully-integrated pressurization system.
Program Background and Project Benefits
The mission of the U.S. Department of Energy/National Energy Technology Laboratory (DOE/NETL) Carbon Capture 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 Program portfolio of carbon dioxide (CO2) emissions control technologies and CO2 compression is focused on advancing technological options for the existing fleet of coal-fired power plants in the event of carbon constraints. Studies conducted by DOE have revealed the high cost and energy requirements that exist for CO2 compression. The CO2 captured from a power plant will need to be compressed from 1,500 to 2,200 pounds per square inch absolute (psia) to be effectively transported via pipeline and injected into an underground sequestration site. This compression requires significant power and the penalty can be as high as 8 to 12 percent for pulverized coal (PC) plants and 5 to 7 percent for a typical integrated gasification combined cycle (IGCC) plant. Reduction of the compression cost and energy requirements will benefit the overall efficiency of carbon capture and storage (CCS) for utility applications. The concepts developed in this project can significantly reduce the cost of pressurizing CO2 to pipeline requirements and improve the overall efficiency of CCS systems for all types of power plants. Successful completion of the Phase III project effort should advance the technology to the point of field demonstration testing. Primary Project Goal
The project goal is to examine methods to pressurize CO2 to pipeline pressures while significantly decreasing parasitic energy consumption, assisting central power plants to capture and store CO2 economically. Objectives
The project objectives are to advance CO2 compression and pumping technology to provide double digit power savings compared to a conventional compressor. These efforts are aimed at advancing and evaluating an in-line, multi-stage, internally-cooled centrifugal compressor in a pilot-scale plant in order to improve the mechanical reliability compared to integrally geared compressors. The design will be scalable to accommodate 1000 MW class power plants. Planned Activities
Conduct a thermodynamic and economic analysis to determine the preferred CO2 state for pressurization.
Identify and evaluate intercooling concepts, develop preliminary intercooling designs, and calculate total potential energy savings.
Complete a comprehensive thermodynamic and cost analysis of an IGCC plant incorporating the new pressurization technology.
Design and fabricate a two-stage intercooled compressor test rig based on the analyses and design studies. The flow path will be designed using state-of-the-art turbomachinery design tools and computational fluid dynamics (CFD).
Verify and optimize performance of the intercooled compressor test rig.
Design and fabricate a multi-stage pump test rig based on the analyses and design studies.
Verify and optimize the multi-stage pump test rig.
Design and construct a pilot-scale demonstration of a multi-stage centrifugal compressor with cooled diaphragm technology.
Establish and apply a rigorous performance testing and monitoring program to determine if overall power savings targets are achieved.
Develop and test a third-generation cooled diaphragm design for even greater performance.
Phase I work identified two promising concepts: inter-stage cooling to achieve near-isothermal compression, and liquid CO2 pumping to 2200 psia. The latter concept initially compresses CO2 to 250 psia and then uses refrigeration to condense the CO2 to a liquid. The liquid CO2, which requires significantly less power to compress than gaseous CO2, is then pressurized to 2,200 psia with a considerable cost savings. Preliminary analysis indicates up to a 35 percent reduction in compression power is possible with the new concepts being considered.
Developed and tested an internally-cooled compressor diaphragm that removes the heat of compression between each impeller. A cooling jacket was designed around a state-of-the-art aerodynamic flow path that contained an optimally designed heat transfer enhancement without introducing additional pressure drop.
A compressor test rig was developed by retrofitting an existing centrifugal compressor installed in a closed loop test facility with the new cooled diaphragm. The diaphragms were fabricated to provide accurate aero-dynamic and cooling circuit geometry. The compressor was instrumented and tested; internal instrumentation was included to permit characterization of the stage performance, heat transfer, and pressure drop. The internally-cooled compressor tests demonstrated the effectiveness of the design, which exceeded expectations.
Conjugate heat transfer CFD models were developed and utilized for compressor design verification and optimization.
A new pump loop facility was designed and constructed, adapting an existing cryogenic turbopump for use on liquid CO2. The pump was proven to meet all project objectives in terms of both hydrodynamic and mechanical performance.
After further process modeling—taking into consideration actual pump performance and commercial proposals for the heat exchangers—the liquefaction/pumping approach was deemed less desirable than a pure semi-isothermal solution. Therefore, the decision was made to pursue the pure compression approach and further optimize the heat transfer of the cooled diaphragm.
A cooled diaphragm design was developed that may be applied to high pressures as well, making a pure compression approach with this technology feasible. The effort and project costs originally allocated to design and build the liquefaction plant will be applied to development and single-stage testing of a Generation 3 design employing compact heat exchanger technology.
Phase III is currently underway to develop a new, pilot-scale, multi-stage centrifugal compressor that contains the cooled diaphragm technology. The new pipe loop has been designed and major pieces of equipment are on order. Testing is scheduled for completion in March 2014.