MEETING THE DUAL CHALLENGE A Roadmap to At-Scale Deployment of CARBON CAPTURE, USE, AND STORAGE

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES

A Report of the National Petroleum Council December 2019 This appendix was last updated on March 12, 2021

Appendix F

EMERGING CO2 CAPTURE TECHNOLOGIES

I. INTRODUCTION flue gas, a low enthalpy of reaction with CO2 to reduce the energy needed to break the amine- This appendix describes less mature carbon CO2 bond in the regeneration process, and a low dioxide (CO2) capture technologies, what this energy lost to vaporization of water and to heat- study calls Emerging CO2 Capture Technologies. ing to reduce the amount of steam used and the The appendix divides these into five technology associated energy penalty. As shown in the Tech- types, with a section devoted to each of the fol- nology Readiness Level (TRL) chart in the Execu- lowing: tive Summary of this report, absorption technolo- y Absorption, including second-generation gies range from TRL 1 to TRL 6 based on the U.S. amines and other solvent types, but exclud- DOE’s definitions. ing the mature amine scrubbing technology described in Appendix E. A. History of Testing Advanced Solvents y Adsorbents and Adsorption DOE has developed a Program Portfolio of y Membranes projects that addresses the key challenges of y Cryogenic distillation and the cryogenic solvent-based CO2 capture. The projects, focused process on addressing key barriers in technology deploy- ment, are shown in Table F-1 from the DOE/ y Allam-Fetvedt Cycle. NETL Carbon Capture Program – Carbon Dioxide This appendix concludes with a section titled Capture Handbook, August 2015. “U.S. DOE Funded Projects” that summarizes A number of advanced solvents, in addition to novel or transformational projects that have process improvements and hybrid systems with been sponsored by the Department of Energy potential to reduce CO capture costs, have been (DOE), several of which involve hybrid capture 2 tested at the small pilot or bench scale at the approaches. National Carbon Capture Center (NCCC) and at other test facilities. II. ABSORPTION: SECOND GENERATION AMINES, NONAQUEOUS, WATER- Linde/BASF tested OASE Blue solvent with LEAN, PHASE CHANGE SOLVENTS innovative capture equipment such as a gravity- flow, interstage cooler and unique reboiler design Continued research and development is ongo- at a 1.5 megawatt (MW) pilot-scale for more than ing to address challenges to the deployment of 4,000 hours in 2015 and 2016 at NCCC. Demon- advanced solvents. Some of the main character- strating a regeneration energy as low as 2.7 giga- istics of a desired solvent include a fast reaction joule (GJ)/tonne CO2 with at least 90% CO2 cap- with CO2 resulting in a smaller absorber volume, a ture, the technology was selected for funding by large CO2 carrying capacity to reduce the amount DOE for 10-MW demonstration at the University of solvent needed to separate the CO2 from the of Illinois.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-1 Project Capital Parasitic Process Performer Benefits Scaleup Water Use Focus Costs Load Integration Low Enzyme Akermin regeneration X catalyzed energy Low Battelle Non-aqueous regeneration X PNNL CO -BOL 2 energy High- Process CCS, LLC pressure X X innovation regeneration General Enhanced Aminosilicone X X Electric energetics Organic/ ION Enhanced amine X X X Engineering energetics mixture Advanced amine/ Single- Linde X X X X process process train innovation Modular; Neumann Process solvent X X X Systems innovation agnostic Low Enzyme Novozymes regeneration X catalyzed energy Hydrophobic Enhanced RTI X amine energetics Southern Process Thermal X X X Company innovation management SRI Carbonate- Capital cost X X International based reduction VOC University of Catalyzed eliminated/ X Kentucky high pressure Advanced High- University of amine/ pressure X X X X X Kentucky process regeneration innovation URS/ Piperazine/ Enhanced University of process X X X X energetics Texas innovation Table F-1. Barriers Addressed by the Solvent-Based Capture R&D Department of Energy/ National Energy Technology Laboratory Program Portfolio

ION Engineering developed an advanced sol- to monoethanolamine (MEA), ION moved forward vent that was demonstrated at NCCC in 2015 dur- with larger-scale testing conducted at Technology ing an 1,100-hour campaign. With a 30+% reduc- Centre Mongstad (TCM) and has sought other tion in regeneration energy requirements relative opportunities to continue development.

F-2 MEETING THE DUAL CHALLENGE University of Texas at Austin tested an The University of Kentucky has performed field advanced flash stripper with piperazine solvent work for the two-stage stripping concept with a (PZ) at NCCC in 2018, showing a 40% reduction in heat integration method using a Hitachi advanced regeneration energy relative to MEA with further solvent in a 0.7-MW small pilot system. testing anticipated during 2019. The University of Notre Dame has identified GE Global tested its continuous stirred-tank several promising ionic liquids (IL) for post- reactor and nonaqueous GAP-1 solvent at NCCC combustion CO2 capture. Microencapsulation in 2016 and 2017. GE received DOE Phase I fund- of these ILs in a polymer coating to alleviate ing to evaluate a demonstration-scale 10-MW high viscosity is being investigated at a lab-scale test at TCM but is not pursuing further develop- resulting in optimal heat of absorption. ment at this time. CCUS Artist ______Date ______ACProgress ______has BA been______made to reduce the para- RTI International (formerly Research Trian- sitic load and the energy penalty due to CO2 cap- gle Institute) operated a nonaqueous solvent at ture. Parasitic load includes the work lost due to NCCC in 2018 and continues development with steam consumption for CCS and capture auxil- testing at TCM. iaries plus the energy required for compression of CO Codexis performed testing of a bench-scale 2 from the stripper. Figure F-1 shows the system using carbonic anhydrase enzymes with progress in lowering parasitic load for solvent methyl diethanolamine (MDEA) at NCCC in post-combustion capture in the DOE/NETL proj- 1 2012. Although the testing confirmed the sta- ects as of 2015. bility of the enzyme and robust system opera- tion, plans to further develop the technol- 1 U.S. Department of Energy, National Energy Technology Labora- ogy were delayed due to company changes in tory. (August 2015). DOE/NETL Carbon Capture Program – Carbon research priorities. Dioxide Capture Handbook.

400 7 M MONOETHANOLAMINE, DOE/NETL CHILLED AMMONIA

2

350 7 M MONOETHANOLAMINE, DOE/NETL NOTRE DAME LINDE 300

250 LINDE

AKERMIN 200 CCS/GPS KILOWATT HOUR PER TONNE OF CO TONNE HOUR PER KILOWATT PULVERIZED COAL ) PULVERIZED (SUPER-CRITICAL ION 150 2006 2007 2008 2009 2010 2011 2012 2013 2014 YEAR Source: DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015.

Figure F-1.Figure Reduction F-1. Reduction in Parasitic in Load Parasitic for Solvent-Based Load for Solvent-Based Capture DOE/NETL Capture Projects DOE/NETL Projects

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-3 B. Future Work with At a bench scale, NETL will manage projects Advanced Solvents that concentrate on transformational technolo- gies such as the following: DOE’s Transformational Large-Scale Pilots y The University of Illinois will advance a bipha- program began its Phase I kickoff in June 2018.2 sic CO2 absorption process. It is structured in three phases. This program supports the design, construction, and opera- y SRI International will develop further a water- 3 tion of two large-scale pilots (10-MW) for trans- lean, mixed salt based solvent technology. formational coal technologies enabling a step y ION Engineering will be conducting testing on change in coal powered system performance, a novel solvent to further understand the key efficiency, and cost of electricity. Phase I will performance indicators and validate perfor- include team commitments, site selection (and mance. environmental analysis), pre-FEED (Front End Engineering Design) design basis, and cost share A list of active and completed projects in the DOE/NETL Carbon Capture R&D Program for for Phase II. Two of the CO2 capture projects chosen for Phase I are solvent projects. solvent-based post-combustion capture is shown in Table F-2.4 The Board of Trustees of the University of Illinois will be investigating the Linde/BASF C. Challenges and Research Needs for Advanced Post-Combustion CO2 Capture Tech- Solvents nology. The major research emphasis should include The University of Kentucky Research Foun- novel solvents such as nonaqueous, water-lean, dation will be furthering their UKy-CAER Heat- and multiphase solvents, in addition to improv- Integrated Transformative CO2 Capture Process. ing already existing solvents. The ideal solvent would have performance with high CO capture, DOE is supporting testing to scale up CO 2 2 efficient regeneration of the solvent with low capture technologies at engineering scale using energy requirements, utilizing environmentally existing host site infrastructure at TCM. Projects friendly processes. Since solvents are relatively include the following: mature and have been developed over several y RTI International’s Nonaqueous Solvent-Based decades, research for transformational technolo- Process gies needs to seek clear advantages over existing technologies (e.g., amines). y SRI International’s Mixed-Salt Process, using a physical solvent 1. Water-Lean Solvents y Fluor’s Multi-Component Solvent Test, with a Water-lean solvents maintain the chemical water-lean solvent. selectivity benefits of the water-based solvents Under DOE’s Funding Opportunity Announce- while reducing the energy requirements for ment (FOA) 1791 Area of Interest (AOI) 2, which regeneration by exploiting the lower specific heat includes initial engineering, testing, and design of organics compared to that of water. The novel solvents will also have the potential advantage of a commercial-scale, post-combustion CO 2 of using the same infrastructure as the first- and capture system, a commercial-scale Techno- second-generation aqueous amine processes. Economic Analysis (TEA) will be performed by ION Engineering with a nonaqueous solvent and All water-lean solvents employ variations of by the University of North Dakota with an amine the following three formulations: carbamate, solvent.

3 Litynski, J. (2018). 4 U.S. Department of Energy, National Energy Technology Labo- 2 Litynski, J. (2018). Transformational Large Scale Pilots – Progress ratory. (April 2018). DOE/NETL Capture Program R&D: Compen- and Next Steps [PowerPoint slides]. dium of Carbon Capture Technology, 04.2018–1000.

F-4 MEETING THE DUAL CHALLENGE Project Focus Participant Technology Maturity ACTIVE Novel Electrochemical Regeneration of Massachusetts Institute of Technology 1-MWe Amine Solvents Slipstream Demonstration Using Advanced University of Kentucky 0.7-MWe Solvents, Heat Integration, and Membrane Separation

Biphasic CO2 Absorption with Liquid-Liquid University of Illinois at Urbana- Lab Phase Separation Champaign Piperazine Solvent with Flash Regeneration URS Group 0.5-MWe

Microencapsulated CO2 Capture Materials University of Notre Dame Lab

Direct Air Capture from Dilute CO2 Sources Carbon Engineering LTD Pilot-Scale Nonaqueous Solvent RTI International Bench-Scale, Actual Flue Gas

Linde/BASF CO2 Capture Process University of Illinois at Urbana- 15-MWe Champaign Low-Aqueous Solvent ION Engineering, LLC 0.6-MWe and 12-MWe Phase-Changing Absorbent GE Global Research Bench-Scale, Simulated Flue Gas

CO2-Binding Organic Liquid Solvents Pacific Northwest National Laboratory Lab Aminosilicone Solvent GE Global Research 10-MWe Ammonia- and Potassium Carbonate-Based SRI International Bench-Scale, Simulated Flue Gas Mixed-Salt Solvent Amine-Based Solvent and Process Southern Company Services, Inc. 25-MWe Improvements Waste Heat Integration Southern Company Services, Inc. Pilot-Scale, Actual Flue Gas COMPLETED Slipstream Novel Amine-Based Linde LLC 1.5-MWe Post-Combustion Process Chilled Ammonia Process Improvements GE Power Bench-Scale, Simulated Flue Gas Carbonic Anhydrase Catalyzed Advanced Akermin, Inc. Bench-Scale, Actual Flue Gas Carbonate and Non-Volatile Salt Solution (“Solvents”) Carbon Absorber Retrofit Equipment Neumann Systems Group 0.5-MWe Novel Absorption/Stripper Process William Marsh Rice University Bench-Scale, Simulated Flue Gas Gas-Pressurized Stripping Carbon Capture Scientific Bench-Scale, Real Flue Gas Solvent + Enzyme and Vacuum Regeneration Novozymes North America, Inc. Bench-Scale, Simulated Flue Gas Technology Optimized Solvent Formulation Babcock & Wilcox Bench-Scale Simulated and Actual Flue Gas Hot Carbonate Absorption with Crystallization- University of Illinois at Urbana- Lab Enabled High-Pressure Stripping Champaign

Chemical Additives for CO2 Capture Lawrence Berkeley National Laboratory Bench-Scale, Simulated Flue Gas Self-concentrating Amine Absorbent 3H Company, LLC Lab Ionic Liquids University of Notre Dame Lab Novel Integrated Vacuum Carbonate Process Illinois State Geological Survey Lab POSTCAP Capture and Sequestration Siemens Energy Inc. 2.5-MW Reversible Ionic Liquids Georgia Tech Research Corporation Lab Phase Transitional Absorption Hampton University Lab

(Pre-Combustion) CO2 Capture Using SRI International 0.15-MWe AC-ABC Process Table F-2. Post-Combustion Solvent Projects in DOE/NETL Carbon Capture Program

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-5 alkylcarbonate, or azoline-carboxylate. These uid/solid assembly (precipitating). Phase change solvents are designed to be nonvolatile to mini- during the absorption/desorption process of cap- mize fugitive emissions. The enthalpies of CO2 ture has the potential to greatly enhance per- absorption for the water-lean solvents are com- formance. The opportunities that phase change parable to those of aqueous solvents at -50 to -90 could present are as follows: kilojoules per mole CO (kJ/mol CO ), demon- 2 2 y Ability to form a high-density CO rich phase strating similar viability and selectivity for post- 2 so that only part of the solvent will need regen- combustion capture. eration Water-lean solvents have been shown to deliver y Intensification of desorption at lower temper- efficiency gains. Distinguishing properties rela- atures of less than 100°C by using waste low- tive to aqueous solvents include physical state, value, heat streams contact angle, wettability, viscosity, volatility, y thermal conductance, and solvation free energy. Release of CO2 at high pressure y Precipitate bound CO2 or the reactant. Water-lean solvents have reported lower reboiler energies of 1.7 to 2.6 gigajoules per Systems that incorporate combinations of tonne CO2 (GJ/tonne CO2) compared to the amines, inorganic salts, organic solvents, and DOE NETL Case 10 with 3.5 GJ/tonne CO2 and water have only been studied recently and have the second-generation amine scrubbing per- shown the potential for reduced energy require- formance of 2.2-2.4 GJ/tonne CO2. An increase ments and improved performance. of 2.1% to 7.1% in net plant efficiency is also expected compared to DOE NETL Case 10 with 3. System Studies and Modeling these solvents.5 However, there is debate as to Molecular modeling and simulation tools whether the capital cost will be that much lower have advanced tremendously. The challenge is due to the higher viscosity of the organic sol- to accurately predict the properties of a poten- vents, with arguments that water-lean amine will tial solvent using the molecular understanding not significantly reduce energy use compared to obtained by using these tools. Using the lessons a second-generation aqueous amine and that the learned in bench- and pilot-scale solvent system second-generation amine scrubbing systems lose testing with improvements in modeling will more little efficiency and can be implemented with lit- accurately enable the design of new, effective sol- tle additional capital cost.6 vent systems. Advances in fundamental theory Most water-lean solvents tolerate acceptable and computational and experimental capabilities levels of water. All have shown stable water load- will enable design of solvent systems for a range ing (up to 10 weight %) without need for exten- of CO2 sources from a wide variety of industrial sive water management equipment. There are applications.7 no reported instances of aerosols or foaming, and these solvents also may be less corrosive than the 4. Challenges to Power Retrofits aqueous solvents. A challenge to the retrofitting of CO2 capture in the power sector for mature amine technol- 2. Multiphase Solvents ogy is amine’s susceptibility to parasitic, irre- Multiphase solvents can develop more than one versible reactions with other species in the flue liquid phase (de-mixing) or they can form a liq- gas, including SOx, NOx, mercury, and particu- lates. Therefore, a retrofit using amine technol- 5 Heldebrant, D. J., Koech, P. K., Glezakou, V. A., Rousseau, R., Mal- ogy is typically preceded by installation of other hotra, D., and Cantu, D. C. (2017). “Water-Lean Solvents for Post- Combustion CO2 Capture: Fundamentals, Uncertainties, Oppor- tunities, and Outlook,” Chemical Reviews 117, p. 14. 7 U.S. Department of Energy, Office of Fossil Energy, “Accelerat- 6 Rochelle, G. and Yuan Y. “Water-Lean Solvents for CO2 Capture ing Breakthrough Innovation in Carbon Capture, Utilization, Will Not Use Less Energy Than Aqueous Amines,” 14th Green- and Storage,” Report of the Mission Innovation Carbon Capture, house Gas Control Technologies Conference, Melbourne, 21-26 Utilization, and Storage Experts’ Workshop, September 2017. October 2018 (GHTG 14). Mission Innovation.

F-6 MEETING THE DUAL CHALLENGE scrubbers that remove these pollutants. Unfor- swing adsorption (VSA) process are separating tunately, the cost of installing these scrubbers to out the CO2 from the steam methane reformer enable a CO2 capture retrofit with amines is pro- syngas for injection in the West Hastings oil field hibitive. Early-stage technologies may overcome for enhanced oil recovery. The CO2 separation this multi-pollutant challenge by removing all takes place upstream of the existing PSA process 10 the pollutants. for capturing H2.

Zerronox offers a pulsed electron beam tech- To advance sorbents as a viable CO2 capture nology originating from the Naval Research Lab- solution, research and development has been oratory. The beam reduces acid gases like NOx underway to demonstrate sorbents’ low cost, to their elemental gases. The team is working to thermal and chemical stability, resistance to 8 extend the technology to CO2 capture. attrition, low heat capacity, high CO2 loading capacity, and high selectivity for CO2. CO2 cap- The CEFCO Process uses aerodynamic physics ture adsorbents employ either physical or chemi- (shockwaves) to achieve what they call “free jet cal adsorption, and compared to solvents may collision scrubbing” to separate pollutants in flue offer lower energy penalty, greater flexibility in gas. Unlike sorbent-based processes, this process operating temperature ranges, and smaller envi- 9 is truly continuous. ronmental impacts. As shown in the TRL chart in the Executive Summary of this report, adsorption III. ADSORBENTS AND ADSORPTION technologies range from TRL 2 to TRL 7 based on the U.S. DOE’s definitions. A. History of Testing Adsorbents To gauge the progress in technological advance- The removal of CO2 from gas streams via ments in the area of adsorbents, a good metric for adsorption is not a new concept. Throughout comparison is the reduction of energy penalty in the manned space missions, solid sorbents have terms of MWh/tonne CO2. Figure F-2 shows the been used to remove CO2 at low concentrations progress for sorbent-based capture to reduce the (<1%) from air. Regenerable sorbents have been parasitic load.11 employed since the 1990s in the space shuttle and for the International Space Station. Numerous completed DOE-supported projects based on amine-based adsorbents include the Cryogenic air separation uses sorbent material following: to remove water vapor and CO2 from feed air typi- cally in molecular sieve units. Zeolite 13X is com- y NETL’s Research and Innovation Center staff monly used since zeolites in general have a high operated a bench-scale sorbent unit at NCCC in 2014 to evaluate accumulation of trace ele- affinity for water and great selectivity for CO2. ments and sorbent degradation with silica- Hydrogen recovery at refineries is the most supported amine sorbents. The unit operated common application of sorbents in large gas sep- in circulating and batch modes, with post-test aration operations. The hydrogen is separated thermo-gravimetric analysis of sorbent sam- out of the gas mixture from the steam methane ples showing no permanent loss of CO2 capture reformer syngas. The pressure swing adsorption capacity. Following testing at the center, NETL (PSA) systems, with commercially available sor- continued sorbent work to improve material bents such as molecular sieve (zeolites), activated characteristics, although the group’s current carbon, activated alumina, or silica gel, are used CO2 capture work is focused on membrane to create relatively pure H2 from the syngas to be material development. used in the refinery process. At Valero Energy’s Port Arthur Texas refinery, sorbents in a vacuum 10 U.S. Department of Energy, National Energy Technology Labora- tory, DOE/NETL Carbon Capture Program – Carbon Dioxide Cap- 8 Zerronox, “Cleaner Emissions with Electrons,” (2015). http:// ture Handbook, August 2015. www.zerronox.com/index.html. 11 DOE/NETL Carbon Capture Program – Carbon Dioxide Capture 9 CEFCO, http://www.cefcoglobal.com/. Handbook, August 2015.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-7 CCUS Artist ______Date ______AC ______BA ______

0 100 200 300 400 500 600 2009 2010 2011 2012 2013 2014 2015

MWh/TONNE CO2 600

2 GEORGIA TECH 500

400 CASE 10 ENVERGEX LLC TDA RTI/PENN STATE 300 UOP WR GRACE SRI 200 TDA (7580) TDA (13105) 100 MEGAWATT HOUR PER TONNE OF CO TONNE HOUR PER MEGAWATT INNOSEPRA 0 2009 2010 2011 2012 2013 2014 2015 YEAR Source: DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015.

FigureFigure F-2. F-2. ProgressProgress inin Reducing thethe Energy Energy Penalty Penalty of of Sorbent-Based Sorbent-Based Capture Capture

y Georgia Tech Research Corporation developed DOE’s research portfolio in carbon-based a rapid temperature swing adsorption (TSA) adsorbents includes many projects performed by system using polymer/supported amine com- TDA Research: posite hollow fibers at the bench scale. The fast cycling would significantly reduce capital y TDA Research has developed a CO2 capture costs and heat integration of the adsorption process using dry, alkalized alumina sorbent, step would decrease the operating costs. featuring low cost, low heat of adsorption, and capability of near-isothermal, low-pressure y ADA-Environmental Solutions performed operation to achieve lower regeneration 1-kW scale field tests with four supported energy than solvent-based processes. TDA has amine sorbents. installed a small post-combustion pilot-scale y Aspen Aerogels, Inc. designed an amine func- test unit at NCCC and will complete testing tionalized aerogel sorbent, developed a pro- in 2019. duction process, and tested at a bench scale to complete a techno-economic analysis of the y TDA Research’s testing of a solid CO2 sorbent system. for pre-combustion syngas at the NCCC consis- tently demonstrated the capability to remove y RTI International developed a polyethyleni- more than 90% CO2. TDA also tested a com- mine supported over silica in a molecular bas- bined WGS/CO2 sorbent system with an inno- ket sorbent to make a more cost-effective alter- vative heat management component. When native. parameters were adjusted to achieve 90% CO y The University of Akron developed low-cost conversion in the WGS stage, the overall CO2 sorbents by integrating metal monoliths with capture rate was greater than 95%. TDA scaled amine-grafted silica, which they tested at a up testing from bench- to small-pilot-scale 15-kW scale. (0.1-MW) with a CO2 sorbent (without water

F-8 MEETING THE DUAL CHALLENGE gas shift) process, again demonstrating high erable metal carbonate-based sorbent result- CO2 capture and stable operation. After tests ing in low regeneration energy penalty. And at the NCCC, the TDA 0.1-MW test skid was NRG Energy along with Inventys developed the shipped to China’s Sinopec facility for further VeloxoTherm™ technology platform, an intensi- testing. fied and rapid-cycle temperature swing adsorp- tion process designed to test a wide-range of sor- y SRI International tested a bench-scale sorbent bent types. Inventys has made plans to utilize the process at NCCC in 2013 and 2014 using car- platform at NCCC and TCM.12 bon microbead sorbents, which offer low heat requirements, high CO2 adsorption capacity, For further discussion, please refer to the com- and excellent selectivity. Performance indica- pleted projects described in the 2018 DOE/NETL tors were lower than expected based on pre- Capture Program R&D: Compendium of Carbon vious testing of SRI’s smaller unit at the Uni- Capture Technology report. versity of Toledo, with CO2 capture efficiency at 70%. Although measures were identified to improve performance, SRI currently has no B. Planned Work with Adsorbents plans for further testing. DOE/NETL’s focus for sorbents includes devel- opment of low-cost, durable sorbents that have The zeolite-based projects supported by DOE high selectivity, high CO adsorption capacity, in the past emphasized the overall capture 2 and little to no attrition during multiple regener- cycle and the improvement of zeolite structure ation cycles. Table F-3 lists the ongoing sorbent in the beds. projects as well as the completed projects in the 13 y For example, W. R. Grace investigated a rapid carbon capture program. PSA process with simplified heat manage- TSA systems being tested are provided in the ment using a commercially available zeolite following list. TSA is where CO is adsorbed on a adsorbent crushed and coated onto a metal foil 2 high surface area solid at low temperature (40°C structure. to 60°C) and are regenerated by steam (80°C to y Also, Innosepra LLC developed a microporous 150°C). Typically, these are chemisorbents in material with low heat of adsorption and novel rotary beds or circulating beds. process cycles. y RTI International’s Dry Carbonate Process – Metal-organic frameworks (MOFs) are highly sodium carbonate to sodium bicarbonate reac- designable and tailorable with limitless combi- tion for post-combustion nations of metals and organic compounds and y KIER (Korean Institute of Energy Research) can be used for many different applications such process with dual fluidized beds at a pilot-scale as CO2 capture. MOFs are strong 3D structures (10 MWe) with exceptional surface area. MOFs have the potential to be superior to zeolites and other sor- y Climeworks – Distributed Air Capture with bents; however, cost of materials and stability in amine impregnated cellulose fibers; 900 t/yr the presence of water vapor are challenges. In CO2 at the pilot unit in Hinwil, Switzerland 2007 to 2010, UOP investigated a large selection y Inventys VeloxoTherm – rotary wheel with of MOFs, narrowing to seven that exceeded tar- diamine-functionalized commercial silica gel, gets, and identified types of favorable structures. pilot underway at NRG Energy Study into the critical property of hydrothermal stability by UOP was also done in detail. Applying MOFs for CO2 capture is currently a very active research area. 12 U.S. Department of Energy, National Energy Technology Labora- tory. (January 2013). Clean Coal Research Program: Carbon Cap- ture Technology Program Plan. Other past projects sponsored by DOE/NETL 13 U.S. Department of Energy, National Energy Technology Labo- include the University of North Dakota where ratory. (April 2018). DOE/NETL Capture Program R&D: Compen- researchers developed a process using regen- dium of Carbon Capture Technology, 04.2018–1000.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-9 Post-Combustion Project Focus Participant Technology Maturity ACTIVE Pressure Swing Adsorption Process with Georgia Tech Research Lab Novel Sorbent Corporation Porous Polymer Networks Texas A&M University Lab Novel Solid Sorbent SRI International Bench-Scale, Actual Flue Gas Alkalized Alumina Solid Sorbent TDA Research, Inc. 0.5-MWe Fluidizable Solid Sorbents Research Triangle Institute Lab COMPLETED Advanced Aerogel Sorbents Aspen Aerogels, Inc. Bench-Scale, Simulated Flue Gas Temperature Swing Adsorption with NRG Energy, Inc. Structured Sorbent Rapid Pressure Swing Adsorption W. R. Grace and Co. Bench-Scale, Simulated Flue Gas Advanced Solid Sorbents and Processes RTI International Bench-Scale, Simulated Flue Gas for CO2 Capture Cross-Heat Exchanger for Sorbent-Based ADA-ES, Inc. Bench-Scale, Simulated Flue Gas CO2 Capture Low-Cost, High-Capacity Regenerable TDA Research, Inc. Bench-Scale, Actual Flue Gas Sorbent Rapid Temperature Swing Adsorption Georgia Tech Research Bench-Scale, Simulated Flue Gas Corporation Novel Adsorption Process InnoSepra, LLC Bench-Scale, Actual Flue Gas Hybrid Sorption Using Solid Sorbents University of North Dakota Bench-Scale, Actual Flue Gas Metal Monolithic Amine-Grafted Zeolites University of Akron 15-kW, Simulated Flue Gas

CO2 Removal from Flue Gas Using UOP Lab Microporous MOFs A Dry Sorbent-Based Post-Combustion RTI International Bench-Scale, 1 tonne per day, CO2 Capture Actual Flue Gas Pre-Combustion Project Focus Participant Technology Maturity ACTIVE High Capacity Regenerable Sorbent TDA Research, Inc. 0.1-MWe COMPLETED Sorbent Development for WGS URS Group Bench-Scale Simulated Syngas Novel Concepts Project Focus Participant Technology Maturity Novel Concepts/Integrated Temperature Altex Technologies Lab and Pressure Swing Carbon Capture Corporation System Table F-3. Sorbent Projects in U.S. Department of Energy/ National Energy Technology Laboratory Carbon Capture Program

y TDA Research alumina sorbents (fixed bed, Opportunities for adsorbent CO2 capture steam regeneration) include enriching natural gas from wells with y Seibu Giku ceramic wheel. high CO2 content, coal or biomass gasification, CO2 recovery from food and dry ice industries, PSA and VSA systems have numerous vendors and CO2 recovery from petrochemical, oil, steel, that are undergoing research. These typically use cement, landfill gas. At the Otway Basin Coop- physisorbents in fixed beds. erative Research Center for Greenhouse Gas

F-10 MEETING THE DUAL CHALLENGE Technologies (CO2CRC) facility, testing of cap- CO2 capacity than the field tests at NCCC of ture materials to develop cost-effective pro- approximately 60x scale.16 cesses to capture CO2 from high CO2 content natural gas wells.14 Under the Scaling of Carbon Capture Tech- nologies to Engineering Scales using Exist- More work continues in Saskatchewan, Can- ing Host Site Infrastructure (FOA 1791 AOI 1), ada, where Inventys and Husky Energy will TDA Research will be designing, constructing, begin pilot testing in Q1 2019 with the Veloxo- and operating a 1-MW post-combustion hybrid Therm Process capture system. This system uses membrane-sorbent system. The polymeric structured solid sorbent in a rotary mechanical membrane will be developed by Membrane contactor to enable rapid sorption/desorption Technology and Research, Inc. (MTR) and will and temperature cycling. The testing at Husky provide the bulk of the CO2 separation with the Energy is a 30 tonnes per day (TPD) pilot dem- sorbent extracting the remainder to achieve 90% onstration. A 0.5 TPD field demonstration plant capture.17 is already at this location for rapid development of new adsorbent structures. Inventys is offer- C. Challenges and Research Needs for ing commercial modular skid plants that will Adsorbents capture 30 to 600 TPD of CO2 at $30 to $100/ tonne. Inventys’ first fully commercial manu- CO2 capture based on sorption/desorption facturing line is expected to be at full capacity of gases by a solid has the potential to greatly by the end of 2020. reduce the energy requirements and the capital costs compared to the current capture technolo- To accelerate the development and commer- gies. The key challenge for sorbents is to pair cialization of second-generation CO2 capture with the newly developed, tailored materials with the new sorbent materials, Inventys in partnership specific CO2 capture applications and be able to established the International Carbon Capture integrate the two predictively with modeling and Center for Solid Sorbent Survey. The objective of computational tools. the center is to move novel sorbent material from the laboratory to the real-world conditions and to Four principal challenges were cited in using establish new standards in the characterization of sorbents in CO2 capture as absorbents as well as new sorbent material and perform benchmarking in looping technologies: of capture processes with rapid cycling. The test- y Design and create tailor-made materials with ing with the VeloxoTherm technology platform at the desired attributes 100 to 500 kg/day has been deployed at the facili- ties of Inventys in Vancouver, British Columbia, y Understand the relationship at the molecular, and the National Carbon Capture Center in the microscopic, and macroscopic levels between United States, and the Technology Centre Mong- the structure and the properties of the material 15 stad in Norway. y Advance the long-term reactivity, recyclabil- ity, and robust physical properties of materials TDA Research started commissioning their within the process pre-combustion PSA sorbent system at Sinopec’s Nanhua Plant in October 2018. This system was y Produce optimal integration between materials previously tested at the NCCC in 2017. The test and process engineering. skid was modified to maintain a slightly higher

16 Alptekin, G. (2018). “Pilot Testing of a Highly Efficient Pre- combustion Sorbent-based Carbon Capture System,” (Contract 14 Webley, P., Singh, R., and Xiao, P. (April 2017). “Adsorption Pro- No. DE-FE-0013105), presented at the 2018 DOE/NETL CO2 Cap- cesses for CO2 Capture: An Overview,” presentation at CO2 Sum- ture Project Technology Review Meeting. mit III: Pathways to Carbon Capture, Utilization, and Storage Deployment, ECI Digital Archives. 17 U.S. Department of Energy. (February 2018). “Energy Depart- ment Invests $44M in Advanced Carbon Capture Technologies 15 Inventys Inc. (2018). Manufacturing & Testing Centre http:// Projects.” https://www.energy.gov/articles/energy-department- inventysinc.com/technology/. invests-44m-advanced-carbon-capture-technologies-projects.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-11 Over the last 15 years, new porous adsorbent that the driving force can be applied with mini- materials with molecular designed attributes mal energy and materials. Further research is have proliferated in the form of MOFs, covalent needed into how to optimally expose the gas to organic frameworks, and several other types of the materials to get sorption/desorption. Much porous polymer materials. These advanced solids emphasis is given to matching the material with will require less infrastructure and lower capture the process. The first step is to determine the costs. These porous materials have not been lim- driving force to use (temperature, pressure, or ited to a bed configuration but are also applicable vacuum cycling). And then, what combination is to membranes. needed to absorb and desorb so that the required feed conditions and other specifications are met. New sorbents, specifically MOFs offer to com- There is a strong dependence of the driving force bine the high surface area of zeolites and acti- with the feed conditions. vated carbons with tailored, tunable pore geom- etry and chemistry to enhance their selectivity. Other challenges center around impurity This is important for CO2 capture since sorbents removal, heat management, and fluid flow. should selectively bind only CO2. MOFs can also Important design considerations include the be tuned for other industrially important gas- need for flexible operation to adapt the cycling gas separations, so their path to market may be of PSA, TSA, or VSA to the real time demand for driven by applications other than CO2 capture. the capture plant. One key strategy has been to Two examples of MOFs used in other gas separa- reduce the cycle time in operations.20 tion process are from NuMat Technologies, Inc. and Mosaic Materials, Inc. NuMat is a spinoff MOFs exhibit sharp temperature and pressure from Northwestern University that combines stepwise pathways to absorption and desorp- high-throughput computational modeling and tion which lead to lower parasitic energy loads experimentation to develop new MOFs. NuMat and faster kinetic rates. Key challenges for these was recently awarded a $9M contract from the materials include sensitivity to oxidation, water, 21 U.S. Army to produce MOFs to protect soldiers and degradation caused by CO2. from toxic agents.18 Mosaic Materials, a spinoff In the newly awarded FOA 1792, organizations from the University of California Berkeley, is that are pursuing bench-scale testing in the sor- developing a MOF that uses a unique “coopera- bents area include the following: tive binding” mechanism that gives the material higher CO2 capture capacity than other sorbents. y Electricore, Inc. is developing a process that The MOF can be used in CO2 capture from exhaust includes a dual-absorbent bi-layer structured gas, but it is also applicable to CO2 capture from adsorbent design with a thermal conductive other process streams such as CO2-methane sep- matrix that will allow faster thermal swings arations following anaerobic digestion.19 than a conventional process. y InnoSepra, LLC is developing a novel sorbent- The leading materials for CO2 capture that offer targeted molecular design (e.g., MOFs) have all based process consisting of a flue gas purifica- been discovered in the last 5 years. There are a tion step, a moisture removal step, and a CO2 few bench-scale testing sites available now that adsorption step. Also, the CO2 adsorption bed will allow the validation of the technologies is regenerated with low level heat. including looping. y Rensselaer Polytechnic Institute is developing a transformational, molecular layer deposition, There are challenges to contacting gas with a solid adsorbent in a compact, efficient manner so 20 U.S. Department of Energy, Office of Fossil Energy, “Accelerat- ing Breakthrough Innovation in Carbon Capture, Utilization, 18 Bomgardner, M. (December 16, 2018). “NuMat Gets Contract to and Storage,” Report of the Mission Innovation Carbon Capture, Build a Metal-Organic Framework Facility.” Chemical & Engi- Utilization, and Storage Experts’ Workshop, September 2017. neering News, vol. 96, no. 49. https://cen.acs.org/business/ Mission Innovation. specialty-chemicals/NuMat-contract-build-metal-organic/96/i49. 21 Inventys Inc. (2018). Manufacturing & Testing Centre. http:// 19 Mosaic. (2018). https://mosaicmaterials.com/. inventysinc.com/technology/.

F-12 MEETING THE DUAL CHALLENGE tailor-made, size-sieving sorbent process. The sure swings. Since these modules can be valved technology will integrate these novel sor- so that individual modules can be swapped in bents with an innovative PSA process for post- and out, changes in the module system will not combustion capture. affect the entire process. This configuration also allows for large turn down ratios of as low y TDA Research, Inc. will work on addressing the as 30% to greater than 100%. Also, extremely early stage development of a transformational high on-stream factors can be achieved. Since high-capacity adsorbent with a vacuum con- the membrane module systems are highly mod- centration swing adsorption process and will ular, they typically have a small footprint and evaluate at bench scale in actual coal-fired flue gas. are easily scalable. Membranes can tolerate high concentrations of acid gases and are inert Not awarded in FOA 1792, Auburn University is to oxygen. They also have the potential for investigating solid sorbent-based long-term CO2 inherent energy efficiency and no additional removal without capture capacity degradation by water use. The TRL chart in the Executive Sum- introducing a regenerative three-stage cycling mary of this report shows membrane technolo- in a reduction-carbonation-calcination process. gies ranging from TRL 3 to TRL 8+. This regeneration of composite solid sorbent at high temperature would possibly resolve the per- Several significant challenges for membrane CO2 capture technologies result in a less favorable sistent problem of CO2 capture capacity degrada- tion over time. cost compared to other technologies. CO2 perme- ability and permeance of gas separation mem- branes is lower than desired resulting in large V. MEMBRANES membrane areas and higher capital costs due to A. History of Testing Membranes a larger footprint of membrane modules. Steam is not required in membrane systems; however, Large surface area membranes with high flux auxiliary power is often needed for compression were first developed for reverse osmosis pur- or vacuum pumps to provide driving force for poses in late 1960s to early 1970s. In 1980, Mon- separation. And, membrane life and effectiveness santo developed the first commercial gas sepa- can be reduced by contaminants in the gas feed. ration membrane, called PRISM, mainly used for Life of the modules is a critical factor for the cost hydrogen separation from refinery waste gases. of these systems. Since membranes are competing against the The membrane acts as a filter. Some molecules more established, less costly CO2 capture pro- are allowed to permeate through, while others are cesses, the use of membranes for large CO2 gas separation has been limited to small scale nat- blocked from passing. Membranes can separate ural gas purification. One commercial project gases from a mixture due to differences in per- that uses membrane separation is the Petrobras meability through the membrane for the differ- Lula Oil Field CCS Project capturing 0.7 million ent gases. The gas flux across a unit membrane tonnes per year. Improvements in flux and area under a unit pressure gradient through a selectivity as well as polymer materials and fab- unit membrane thickness is called permeability, rication have continuously decreased the cost of in moles per second per meter squared per Pas- membranes for gas separation. Some examples cal (mol s-1m-2Pa-1). The selectivity is a ratio of of commercially available membranes are the the permeability of gas A to the permeability of PRISM by Air Products, MEDAL by Air Liquide, gas B, or the ratio of permeabilities of different and PolySep by UOP. gases through the same membrane. To achieve separation by the membrane, a large difference Membrane-based CO2 separation has many in permeabilities of the gases is preferred. The advantages compared to other capture differences in physical and/or chemical proper- approaches. Membrane module systems have ties of the gases as well as how they interact with simple operation with no chemical reactions, the membrane determine permeability. Some no moving parts, and no temperature or pres- separation mechanisms are size sieving, surface

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-13 diffusion, solution diffusion, facilitated trans- bundled together cylindrically over a central core port, and ion transport. Since the feed gas is which is a perforated tube called a bore. pressurized to achieve a high flux and the mem- brane is very thin, at several hundred nanome- Or, membrane modules can be made with thin ters to several microns, the membrane is coated sheets of polymer arranged in spiral wound fash- onto a thick, porous substrate to have mechanical ion. The feed gas enters the module and flows strength to resist this force.22 between the membrane leaves. The retentate flows over the leaves and exits the other end There are four main configuration options for whereas the permeate spirals inward to a central module designs, two mechanical designs and two core collection tube. Refer to Figure F-3. material-type configurations. For the mechani- cal design there are tubular and plate and frame MTR has developed a unique spiral wound-type options. For the tubular design, numerous tubes module (see Figure F-4). This module introduces Artist ______Date ______AC ______BA ______CCUScan be placed into a single cylindrical vessel and sweep gas on the permeate side thus creating this is called a shell and tube design. driving force with no additional pressurization. The permeate central collection tube has a plug For the material-type configurations, there are in the middle to form a counter-current permeate the hollow fiber and sheet fabrications. Hollow flow to the feed gas flow. Another less widely used fibers have an outside, thin layer of dense poly- membrane module tested by MTR is the plate and mer supported by a porous structured sublayer. frame configuration with flat membrane sheets In a module, thousands of these hollow fibers are and use of sweep combustion air. This configu- ration provides a compact large membrane area

22 Ji, G., and M. Zhao. (2017). “Membrane Separation Technology in with low pressure drop. Using the sweep gas for Carbon Capture,” in Recent Advances in Carbon Capture and Stor- separation driving force instead of compressors age p. 59-90, InTechOpen, https://www.intechopen.com/books/ recent-advances-in-carbon-capture-and-storage/membrane- or vacuum pumps will reduce the cost of capital separation-technology-in-carbon-capture. and energy use of the system.

TUBULAR CAPILLARY PERMEATE MEMBRANE POROUS SUBSTRATE FLOW HOLLOW FIBERS

FEED CONCENTRATE FEED CONCENTRATE

PERMEATE

PLATE AND FRAME SPIRAL WOUND PERMEATE CONCENTRATE CONCENTRATE FLOW

PERMEATE MEMBRANES FLOW FEED FEED MEMBRANES PERMEATE CARTRIDGE FEED SPACER

Sources: Torzewski, K., “Facts at your Fingertips—Membrane Configuration,” Chemical Engineering, March 15, 2008; and DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015. Figure F-3. Common Membrane Designs Figure F-3. Common Membrane Designs F-14 MEETING THE DUAL CHALLENGE CCUS Artist ______Date ______AC ______BA ______

A. CONVENTIONAL B. COUNTERCURRENT/SWEEP SPIRAL-WOUND MODULE SPIRAL-WOUND MODULE

DIRECTION OF FLOW DIRECTION OF FEED GAS FLOW

PERMEATE FLOWS OF SWEEP FLOW-DIRECTING GAS FLOWS AND PERMEATE GAS BAFFLE

MEMBRANE ENVELOPE

PERMEATE PERMEATE GAS GAS • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • SWEEP PRODUCT PIPE PRODUCT GAS PRODUCT PIPE PLUG PRODUCT PERFORATIONS PIPE PERFORATIONS PIPE

Source: DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015.

FigureFigure F-4. F-4. Spiral-Wound Spiral-Wound MembMembranerane Module Module F lFlowow P aPatternstterns

The separation of gases with a membrane is in the latest capture R&D in order to enhance dependent on the permeability and the selec- performance or improve energy efficiency. For tivity for the target component in the gas to be example, MTR’s membrane process will be com- removed. The current membranes are limited in bined with an absorption column with 5 meters these characteristics such that a single stage sep- piperazine as the solvent at the initial separa- arator cannot attain the high removal and purity tion. And the Gas Technology Institute is test- objectives like achieving 90% capture and 95% ing their membrane contactor, which incorpo- purity. rates a polyether ether ketone (PEEK) hollow fiber membrane having flue gas on one side of The process configurations for membrane sep- the membrane and amine MDEA solvent on the aration systems are typically a two-stage process, other side. Since the solvent takes the CO2 per- as shown in Figure F-5, with either the retentate meate away from the membrane surface, the from the first stage as feed for the second stage permeate side has near zero CO2 partial pressure (stripper circuit) or the permeate as the feed to creating the separation driving force without the second stage (enricher circuit). Serial enricher compression or vacuum. circuits have been found to be the most energy efficient, with improved efficiency achieved Gas separation membranes are currently used when the second-stage retentate is recycled to in industry for hydrogen separation in ammo- the beginning of the cycle in Figure F-6. Most nia production and petrochemical plants, for arrangements include compression or vacuum separating nitrogen from air, removing CO2 from pumping, which tends to add cost. MTR’s pro- natural gas, and recovering volatile organic com- cess solution incorporates the combustion air as pounds from air or nitrogen. The most commonly a sweep gas to provide the driving force, reducing used membranes for gas separation are made of the need for the energy intensive process units. polymers. The types of membranes include poly- mers, ceramics, supported liquid membranes Hybrid combinations of solvent or sorbent with (facilitated transport membranes), metallic, and the membrane process have been emphasized others such as zeolites.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-15 CCUS Artist ______Date ______AC ______BA ______

— FEED — PERMEATE — RETENTATE MEMBRANE MODULE C COMPRESSOR E EXPANDER P VACCUUM PUMP

FEED RETENTATE

PERMEATE P

FEED RETENTATE C C E

PERMEATE P

SERIAL STRIPPER CONFIGURATION

RETENTATE C E FEED RETENTATE C E PERMEATE

RETENTATE RETENTATE

FEED P PERMEATE P

RETENTATE

RETENTATE FEED P C E PERMEATE

SERIAL ENRICHER CONFIGURATION

Source: DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015.

Figure F-5. Two-Stage Membrane Circuits – Serial Stripper Configuration and Serial Enricher Configuration

F-16 MEETING THE DUAL CHALLENGE CCUS Artist ______Date ______AC ______BA ______

— FEED — PERMEATE — RECYCLE — RETENTATE MEMBRANE MODULE C COMPRESSOR E EXPANDER P VACCUUM PUMP

C E RETENTATE RECYCLE FEED C PERMEATE

RETENTATE RECYCLE

FEED P PERMEATE P

RETENTATE RECYCLE

FEED P C E PERMEATE

Source: DOE/NETL Carbon Capture Program – Carbon Dioxide Capture Handbook, August 2015.

FigureF F-6.igure F-6.Two-Stage Two-Stage Membrane Membrane Circuits Circuits – Serial— Enricher Enricher with Rewithcy cleRecycle Configuration Configuration

Some of the membrane projects that have been temperatures to efficiently separate CO2 from tested or are ongoing are described here: flue gas. Testing at NCCC focused on develop- ment and scale-up of the novel PI-2 membrane y Membrane Technology and Research developed material featuring significantly higher CO flux a two-step membrane, with the first step oper- 2 than commercially available material. The PI-2 ating at vacuum and at a low stage cut, and the module achieved 10 times the normalized CO second step incorporating sweep gas to provide 2 permeance of the commercial module. Air Liq- a final CO capture rate of 90%. After success- 2 uide continues further testing at NCCC. fully operating a bench-scale unit at the NCCC beginning in 2011, MTR employed the lessons y Gas Technology Institute developed a hol- learned to construct and test a pilot-scale ver- low fiber gas-liquid membrane contactor to sion. Continued development included opera- replace conventional packed-bed columns in tion of the larger-scale unit at a Babcock & solvent systems to improve CO2 absorption Wilcox pilot coal-fired boiler for the first oper- efficiency. GTI conducted testing at NCCC in ation with CO2 recycle to a boiler by a mem- 2017 and 2018 and made plans for additional brane process, larger-scale operation at TCM, testing in 2019. and participation in a DOE Phase I project for The performance of facilitated transport mem- demonstration at a commercial NRG Energy branes have been assessed at the Norcem cement coal-fired power plant. factory in Norway employing hollow fiber mem- y Air Liquide evaluated a cold membrane pro- brane modules with up to 18 m2 of membrane cess that combines high-permeance membrane area. Capture was from a high CO2 content flue materials with high CO2 selectivity at subzero gas of 17 mol% wet basis. The test results showed

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-17 that 70 mol % CO2 purity can be easily achieved in permeability and selectivity, stability—both ther- a single stage.23 mal and physical, and tolerance for flue gas con- taminants or syngas, and integration capability The dense metal H2-selective membrane tech- into low pressure drop modules. Membranes for nology that allows production of CO2-free hydro- pre-combustion must also be capable of operat- gen from syngas has greatly progressed during ing in system temperatures of up to 500°F.28 The the past 10 years. Since Tokyo Gas’ demonstra- current and past technology projects for post- and tion of its membrane reformer with natural gas pre-combustion as well as novel emerging mem- as the feed (H2 production capacity of 40 Nm3/h, brane capture projects are listed in Table F-4. 150 kWth), using membranes with thicknesses of about 15 to 20 micrometers (μm),24 efforts have For Phase I of the Transformational Large- been focused on the development a of thinner Scale Pilots program (FOA 1788), MTR will be palladium layers within the membranes (i.e., assembling a team and host site and a pre-FEED <5 microns). A 98-tube membrane separator design basis for consideration in Phase II. Also, (1.8 m2) has been tested in coal-derived syngas MTR will also be testing in the Engineering-Scale at the University of North Dakota Energy and program at TCM with their Advanced Polaris CO2 Environmental Research Center.25 Other activi- Membrane. ties include tests at the NCCC26 under adverse industrial conditions. In 2017, Reinertsen AS and For FOA 1791 AOI 2, EPRI will perform an ini- SINTEF demonstrated a 3 m2 membrane module tial engineering design and cost estimate of a on a syngas-side stream of the Statoil Methanol Post-Combustion CO2 Capture system for Duke Plant at Tjeldbergodden, Norway.27 Energy’s East Bend Station using membrane- based technology. Refer to Table F-4 for active and completed DOE/NETL membrane projects. In developing transformational materials and processes, some of the membrane projects follow: B. Planned Work with Membranes y Gas Technology Institute will perform tests on bench scale graphene oxide-based membranes DOE/NETL’s current focus for membrane cap- and processes (GO-1 and GO-2 membranes ture includes development of low-cost, robust integrated into the proposed process). membranes that have characteristics of improved y MTR will also develop a composite mem- brane consisting of two parallel technology 23 U.S. Department of Energy, Office of Fossil Energy, “Accelerat- developments. First, is to double membrane ing Breakthrough Innovation in Carbon Capture, Utilization, and Storage,” Report of the Mission Innovation Carbon Capture, permeance through overcoming flow restric- Utilization, and Storage Experts’ Workshop, September 2017. tions by replacing conventional porous sup- Mission Innovation. ports used to fabricate composite membranes 24 Yasuda, I., Shirasaki, Y., Tsuneki, T., Asakura, T., Kataoka, A., by using self-assembly isoporous supports. and Shinkai, H. (2003). “Development of membrane reformer for highly-efficient hydrogen production from natural gas,” Proceed- Second is to double the mixed-gas selectivity ings of Hydrogen Power Theoretical & Engineering Solutions Inter- of the MTR Polaris membrane by building on national Symposium V (Hypothesis V), p. 97. work for new materials by State University of 25 Schwartz, J., Makuch, D., Way, D. J., Porter, J. J., Patki, N., Kel- New York at Buffalo. ley, M., Stanislowski, J. and Tolbert, S. (2015). “Advanced Hydro- gen Transport Membrane for Coal Gasification,” final report y University of Kentucky Research Foundation DE-FE0004908, U.S. Department of Energy. will investigate a process with decoupling 26 Castro-Dominguez, B., Mardilovich, I. P., Ma, R., Kazantzis, N. K., Dixon, A. G., and Ma, Y. H. (2017). “Performance of a pilot- absorber kinetics and solvent regeneration scale multitube membrane module under coal-derived syngas for through membrane dewatering and in- hydrogen production and separation,” Journal of Membrane Sci- column heat transfer. The process con- ence 523, 515-523. sists of a temperature-controlled absorber, 27 Peters, T. A., Rørvik, P. M., Sunde, T. O., Stange, M., Roness, F., Reinertsen, T. R., Ræder, J. H., Larring, Y., and Bredesen R. (2017). “Palladium (Pd) membranes as key enabling technology for pre- 28 U.S. Department of Energy, National Energy Technology Labo- combustion CO2 capture and hydrogen production,” Energy Pro- ratory. (April 2018). DOE/NETL Capture Program R&D: Compen- cedia 114, 37-45. dium of Carbon Capture Technology, 04.2018–1000.

F-18 MEETING THE DUAL CHALLENGE Post-Combustion Project Focus Participant Technology Maturity ACTIVE

Selective Membranes for <1% CO2 Sources Ohio State University Lab Subambient Temperature Membrane American Air Liquide, Inc. 0.3-MWe Polaris Membrane/Boiler Integration Membrane Technology and 1-MWe Research, Inc. COMPLETED (in Appendix) Inorganic/Polymer Composite Membrane Ohio State University Pilot-Scale, Actual Flue Gas Composite Hollow Fiber Membranes GE Global Research Bench-Scale, Simulated Flue Gas Low-Pressure Membrane Contactors Membrane Technology and Bench-Scale, Simulated and (Mega-Module) Research, Inc. Actual Flue Gas Hollow-Fiber, Polymeric Membrane RTI International Bench-Scale, Simulated Flue Gas Biomimetic Membrane Carbozyme Lab Dual Functional, Silica-Based Membrane University of New Mexico Lab Pre-Combustion Project Focus Participant Technology Maturity ACTIVE Zeolite Membrane Reactor Arizona State University Bench-Scale, Actual Syngas Mixed Matrix Membranes State University of New York, Bench-Scale, Actual Syngas Buffalo PBI Polymer Membrane SRI International Bench-Scale, Actual Syngas Two-Stage Membrane Separation: Carbon Media and Process Technology, Bench-Scale, Actual Syngas Molecular Sieve Membrane Reactor followed Inc. by Pd-Based Membrane COMPLETED High-Temperature Polymer-Based Membrane Los Alamos National Laboratory Bench-Scale, Simulated Syngas Dual-Phase Ceramic-Carbonate Membrane Arizona State University Lab Reactor Pd-Alloys for Sulfur/Carbon Resistance Pall Corporation Lab Hydrogen-Selective Zeolite Membranes University of Minnesota Bench-Scale, Simulated Syngas Pressure Swing Membrane Absorption Device New Jersey Institute of Technology Lab and Process Nanoporous, Superhydrophobic Membrane Gas Technology Institute Bench-Scale, Simulated Syngas Contactor Process Polymer Membrane Process Development Membrane Technology and Bench-Scale, Actual Syngas Research, Inc. Novel Concepts Project Focus Participant Technology Maturity ACTIVE Electrochemical Membranes FuelCell Energy Inc. 3-MWe Hybrid GO-PEEK Membrane Process Gas Technology Institute – GTI Lab Novel Concepts/ICE Membrane for Post- Liquid Ion Solutions LLC Lab Combustion CO2 Capture Novel Concepts/Encapsulation of Solvents in LLNL – Lawrence Livermore Lab Permeable Membrane for CO2 Capture National Laboratory Source: U.S. Department of Energy, National Energy Technology Laboratory. (April 2018). DOE/NETL Capture Program R&D: Compendium of Carbon Capture Technology, 04.2018–1000. Table F-4. Membrane Projects in DOE/NETL Carbon Capture Program

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-19 a membrane-based dewatering unit, and a in the feed gas and their effect on stability of the multiple-feed pressurized stripper. This new membrane material.29 process can be used with most advanced solvents. The organizations awarded DOE funding through FOA 1792 for membrane testing are the C. Challenges and Research Needs for following: Membranes y The Ohio State University is developing novel transformational polymer membranes and a Over a brief period of about 12 years, mem- two-stage process for CO2 capture from flue branes have entered the market and become the gas. The proposed membrane material is a preferred capture approach for several applica- novel synthesized membrane material with tions. In reference to CCUS, membranes are effi- simple membrane module fabrication. cient, compact and modular, simple to use, and y The State University of New York at Buffalo is environmentally friendly. developing advanced membranes that will be Polymeric membranes have been used exten- solubility-selective, mixed matrix membranes sively at large scale in hydrogen recovery, nitro- comprised of soluble metal-organic polyhedra gen production, natural gas treatment, and vapor in rubbery functional polymers for CO2/N2 sep- recovery sectors. aration.

Research for membranes focuses on polymeric, Other work is ongoing at the University of hybrid, carbon metallic, and ceramic membranes, Colorado Boulder in fabricating and evaluat- as well as composite and dual-phase membranes. ing curable polymer membranes containing The two main areas of research are (1) develop- amine functionalities for use in highly selec- ing an understanding of the transport phenom- tive removal of CO2 from flue gas streams (aka ena at the membrane interface in new materials, CO2 CCRIMP). Also, C-Crete Technologies LLC and (2) fabrication of new design and methods (C-Crete) is developing protocol to control and to produce membrane structures or modules at design nanoporous calcium-silicate materials large scale. with advanced properties for post-combustion CO2 capture. The goal is to develop low-cost, Recent investigations have shown the energy efficient, and chemically/thermally sta- importance of understanding the membrane ble calcium-silicate membranes with highly interfaces and how the properties here affect ordered and controllable pores. reactivity and transport processes. To make significant strides in membranes, the knowl- V. CRYOGENIC DISTILLATION AND THE edge of how to control the properties at the CRYOGENIC PROCESS interfaces is imperative. Phase change can be used to separate compo- Manufacture of novel membrane materials nents from a gas stream. This is typically accom- into effective membrane structures has many plished by cooling the gas stream until one or challenges, in the forming of a dense, thin layer more of the components change phase to either a of novel material on a support structure and in dense liquid or solid phase that can be physically building the membrane structure into a mechani- separated from the noncondensing species. CO cal module unit. An area of opportunity is the 2 capture through phase change has been proposed reduction of concentration polarization related and developed as a means of removing CO2 from to these high-flux membranes and where they are power plant flue-gas streams. applied. Membrane separation properties such as surface absorption and diffusion will change with operating conditions. 29 U.S. Department of Energy, Office of Fossil Energy, “Accelerat- ing Breakthrough Innovation in Carbon Capture, Utilization, and Storage,” Report of the Mission Innovation Carbon Capture, Another area of research will be material spe- Utilization, and Storage Experts’ Workshop, September 2017. cific. The concern is around trace components Mission Innovation.

F-20 MEETING THE DUAL CHALLENGE There are several major advantages of cryo- using cryogenic distillation methods. In 2008, a genic CO2 capture over amine capture systems, commercial demonstration plant was constructed including that there is a physical rather than at its Shute Creek Treatment Facility in LaBarge, a chemical separation performed, there is no Wyoming, with formal testing from March 2012 impact on the steam cycle of the associated to November 2013. ExxonMobil is offering CFZ power plant, the CO2 is pumped to pressure as a technology commercially. liquid minimizing compression energy, and the Sustainable Energy Solutions (SES) LLC has energy consumption per ton of CO2 captured overall is low. Drawbacks include difficulties developed a process, cryogenic CO2 capture associated with solids formation and handling (CCC), that has process flexibility, does not need and large heat transfer areas with tight tem- to integrate with the power plant (it is plug and perature approaches.30 As shown in the TRL play with only electricity needed), can load fol- chart in the Executive Summary of this report, low, and has the ability to capture other flue gas 32 cryogenic process technologies range from trace components, SOx, NOx, and mercury. TRL 3 to TRL 6. CCC is a retrofit, post-combustion method that uses phase change to separate CO and other pol- A. History of Testing the 2 lutants from gases. CO2 is cooled to a low tem- Cryogenic Process perature (about -140°C) that it de-sublimates, or changes from a gas to a solid. The solid CO2 is Cryogenic CO2 capture processes come in many separated from the remaining light gases, melted, forms such as a thermal swing process, an inertial pressurized, and delivered at pipeline pressure. carbon extraction system, cryogenic CO2 capture The technology originated at Brigham Young external cooling loop, and cryogenic CO2 capture University and was developed with support from compressed flue gas. DOE ARPA-e’s IMPACCT program.

A thermal swing process freezes CO2 as a SES has operated several small pilot units solid onto a surface of a heat exchanger. Alstom (1 TPD and 0.25 TPD) from 2014 through the and Shell have investigated this process, but it present with 95-99% capture at a Pacificorp has slowed investigation. In an inertial carbon power station near Glenrock, Wyoming (coal), extraction system, the process expands flue gas Holcim’s Devil’s Slide plant in Utah (cement pro- through a nozzle and a cyclone separates the cessing), and at Brigham Young University’s heat- solids from the gas. The process of cryogenic ing plant (coal and natural gas), and an experi- CO2 capture has energy efficiency advantages mental reactor (coal, natural gas, and biomass).33 that stem from ease of liquid-solid separation Cryopur, EReiE and others have performed pilot and this process pressurizes the CO2 when it is tests and GE has done simulation work to evalu- a liquid as opposed when it is a gas. Another ate the technology.34 SES’s cryogenic process advantage is that other gas impurities are sepa- was part of the demonstration of the first project rated from the gas.31 to collect cement kiln CO2 for utilization in con- In 1986, ExxonMobil demonstrated their Con- crete production. Emissions from the Cementos trolled Freeze Zone (CFZ) technology at the Clear Argos’ Roberta cement plant near Calera, Ala- Lake Pilot Plant near Houston by processing nat- bama, were captured by SES. The captured CO2 was transported and used in concrete opera- ural gas with levels of CO2 as high as 65%. This technology removes impurities from natural gas tions equipped with CarbonCure’s CO2 utiliza- tion technology. This project was an extension of

30 Berger, A. et al. “Evaluation of Cryogenic Systems for Post Com- bustion CO2 Capture,” 14th Greenhouse Gas Control Technolo- 32 Herzog, H. (2018). Carbon Capture. Boston, MA: Massachusetts gies Conference, Melbourne, 21-26 October 2018 (GHGT-14). Institute of Technology Press. 31 Jensen, M., (2015). “Energy Process Enabled by Cryogenic 33 Sayre, A. et al. (July 2017). “Field Testing of Cryogenic Carbon Carbon Capture.” Theses and Dissertations. 5711. https:// Capture.” CMTC-486652-MS. scholarsarchive.byu.edu/etd/5711?utm_source=scholarsarchive. byu.edu%2Fetd%2F5711&utm_medium=PDF&utm_campaign 34 IEAGHG, “Assessment of emerging CO2 capture technologies and =PDFCoverPages. their potential to reduce costs,” 2014/TR4, December 2014.

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-21 the Team CarbonCure’s participation in the NRG the flow of traditional heat exchangers. The 35 COSIA Carbon XPRIZE Challenge. difficulty of removing a solid through deposi- tion in a continuous process is best illustrated Using the same cost assumptions in the by looking at moisture removal. Dehydrating NETL Cost and Performance Baseline report gas streams above 0°C is almost exclusively Volume 1 Revision 2a, September 2013, the CCC accomplished through moisture condensa- cost is reported at $35/tonne CO2 avoided (~$30/ tion and liquid collection. However, water tonne captured) with no plant integration. Using forms solid ice below 0°C, making a continuous existing plant infrastructure should reduce the dehydration process that uses phase change 36 cost further. extremely difficult. Instead, a range of dehy- dration options exist for low dew-point appli- B. Planned Work with the cations that include liquid desiccants, such as Cryogenic Process glycols, and solid desiccants, such as silicas and zeolites. SES is preparing for a 500+ hour test at another Pacificorp Power Plant and is designing a 100TPD Cryogenic gas separations are used at large system (commercial-scale for industrial sector, scale—primarily for air separation operations. pilot-scale for power generation) for further test- For cryogenic air separation the inlet air is dehy- 37 ing. In the Post-Combustion Novel Concepts drated, scrubbed of CO2, then chilled, liquefied area, DOE/NETL has two active projects for cryo- and distilled to separate air into its individual genic separation for capture with SES and Orbital components of oxygen, nitrogen, and other com- ATK (Table F-5).38 ponents at very low temperatures. The dehydra- tion and CO2 removal pretreatment steps are to C. Challenges and Research Needs for remove the two species that would form a solid Cryogenic Process as they are chilled at atmospheric pressure. For cryogenic CO2 capture, moisture removal pres- Carbon dioxide undergoes deposition to form ents a similar challenge. Below 0°C the gas a solid when condensed below its triple point stream either has to be dehydrated to a dew pressure of 517 kPa. When a component under- point of approximately -100°C (<0.1 PPM) or goes deposition in a stream that is being cooled, cooled in a way that does not involve heat trans- it does so on the lowest temperature surface, fer through fixed surfaces. forming a barrier to heat transfer and plugging For all cryogenic systems, thermal integra- tion and temperature management is required

35 Smith, M. (February 2018). “CarbonCure consortium closes to minimize the energy consumption of the the carbon loop for the cement and concrete industries,” JWN process. Thermal recuperation that uses the Energy, https://www.jwnenergy.com/article/2018/2/carbon- available cooling potential in cold internal cure-consortium-closes-carbon-loop-cement-and-concrete- industries/. streams or products to cool incoming gas or 36 Sayre, A. et al. (July 2017). internal streams has to be carefully designed to minimize the exergy loss due to internal heat 37 Sayre, A. et al. (July 2017). transfer or rejection to the environment. An 38 U.S. Department of Energy, National Energy Technology Labo- ratory. (April 2018). DOE/NETL Capture Program R&D: Compen- idealized cryogenic CO2 capture process could be dium of Carbon Capture Technology, 04.2018–1000. envisioned in which there is no lost work from

Project Focus Participant Technology Maturity Novel Concepts/Cryogenic Sustainable Energy Solutions, LLC Bench-Scale, Actual Flue Gas Carbon Capture Process Supersonic Inertial CO 2 Orbital ATK Inc. Bench-Scale, Simulated Flue Gas Extraction System Table F-5. Cryogenic Process Projects in DOE/NETL Carbon Capture Program

F-22 MEETING THE DUAL CHALLENGE heat transfer or heat loss. One would then be test at larger scale is the key path to commer- able to compare existing processes to this ide- cialization.41 alized process to benchmark performance and understand potential for improvements.39 IV. ALLAM-FETVEDT CYCLE A challenge for using cryogenics for flue gases A. Allam-Fetvedt Cycle Process is that CO2 does not form a liquid at atmospheric pressures. Pure CO2 gas forms a solid (dry ice) The Allam-Fetvedt (AF) cycle is a process that when it is cooled to -78.5 C (its sublimation generates power from hydrocarbons while captur- point). So, cryogenic separation of CO2 from flue ing the generated CO2 and water. As depicted in gas is possible, but the formation of solids makes Figure F-7, the AF cycle takes a novel approach to it difficult.40 Equipment for the technology typ- reducing emissions from fossil fuel power gener- ically consists of designs and construction of ation through the use of an oxy-combustion cycle CCUSrefrigeration systems andArtist heat ______exchangers Date ______that thatAC ______employs BAhigh-pressure ______supercritical CO₂ as a are well-developed. However, the engineering working fluid in a highly recuperated manner. At of cyclic operation for frosting and defrosting at the core of the cycle is a supercritical CO2 loop, a reliable, commercial scale may be difficult. A where high-pressure CO2 passes through a tur- bine, is cooled to remove water and impurities,

39 Berger, A. et al. “Evaluation of Cryogenic Systems for Post Com- and then is re-pressurized and reheated in a heat bustion CO2 Capture,” 14th Greenhouse Gas Control Technolo- gies Conference Melbourne, 21-26 October 2018 (GHGT-14). 41 IEA Greenhouse Gas R&D Programme. (December 2014). Assess- 40 Herzog, H. (2018). Carbon Capture. Boston, MA: Massachusetts ment of emerging CO2 capture technologies and their potential to Institute of Technology Press. reduce costs, 2014/TR4.

ANCILLARY BYPASS FLOW 3 4 GASEOUS FUEL CO2 COMP

TURBINE WATER SEP 5 2 1 9 6 H2O OUT

TURBINE RECUPERATOR COOLING 13 8 7 FLOW RECYCLE HEAT RECUPERATION PUMP EXPORT CO2 (ASU OR OTHERWISE) OXIDANT 12 10 PUMP ASU 11 O2

* ASU = air separation unit Source: Allam, R. et al. (2017). “Demonstration of the Allam Cycle: An update on the development status of a high efficiency supercritical carbon dioxide power process employing full carbon capture,” Energy Procedia, Vol. 114, pages 5948-5966.

Figure F-7. Process Schematic of a Simplified Commercial-Scale Natural Gas Allam-Fetvedt Cycle Figure F-7: Process Schematic of a Simplified Commercial Scale Natural Gas Allam-Fetvedt Cycle

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-23 exchanger against the hot turbine exhaust stream most important advantages of the AF cycle comes and returned to the combustor. The inherent the exploitation of this difference between the operational characteristics of the AF cycle allow left part of line “3” and line “6.” it to avoid the necessity of additional capture, clean-up, and compression systems for CCUS. The black parabola on the far left represents The AF cycle is able to utilize a variety of hydro- the bi-phasic “dome” for CO₂. Within this dome carbon fuels. The TRL chart in the Executive CO₂ is a mixture of both gas and liquid. At con- Summary of this report shows AF cycle technol- ditions to the left of the dome, CO₂ is liquid. At ogy ranging from TRL 4 to TRL 6, based on the conditions to the right, CO₂ is a gas. Above the U.S. DOE’s definitions. top of the dome, CO₂ becomes supercritical. In the supercritical realm, CO₂ does not undergo The Allam-Fetvedt cycle is most simply a “phase transition” (changing from liquid to explained when plotted on a pressure-enthalpy gas, and vice versa); instead, CO₂ flows like a (P-H) diagram for carbon dioxide. The P-H dia- liquid while at the same time filling the space gram shown in Figure F-8 has pressure (P) loga- it occupies. rithmically spaced on the x-axis and enthalpy (H), a measure of energy, is linearly spaced on the Another important aspect of the AF cycle can be y-axis.42 Points on this diagram represent the seen by following the beige entropy lines. Think conditions of the CO₂ working fluid at various of these as “railroad tracks.” Thus, on the right, points within the AF cycle. Entropy, a measure when the gases are going through the turbine, of a system’s thermal energy unavailable for con- the drop-in pressure follows the railroad tracks version into mechanical work, is represented by down, and the turbine produces the amount the beige lines. These entropy lines should avoid of energy equal to the difference between the being crossed when moving up and down in pres- enthalpy value at the upper right of the diago- sure. For example, in the turbine this is repre- nal line and the enthalpy at the lower left of the sented by the line going from the upper right of same line. By contrast, on the left, these rail- the diagram down to the lower left (labelled “2” road tracks are steeper, and those for the pump in Figure F-8). Moving from right to left along are steeper (nearly vertical) than those for the the x-axis represents the energy that is gener- compressor. That means the system uses less ated, and the right-left distance of line “2” is the energy to increase in pressure than the energy it amount of power the turbine produces. Moving produced in the turbine from the drop-in pres- from left to right along the x-axis requires ther- sure. Further, on the left, note that less energy mal energy to be injected into the system (such is required by the pump than to compressor (the as via combustion of fuel). Temperature is repre- entropy lines are steeper for the former than the sented by the vertical/semivertical blue lines. latter). The AF cycle exploits this fact to increase its efficiency. To the right, temperature and enthalpy move together, but the temperature lines move very dif- The system design point is where the turbine ferently. Note that at the left part of line “3,” the exhaust stream goes into the heat exchanger temperature lines are clumped together. Observe (where lines two and three meet at point F). The the small amount of enthalpy that leaves the sys- limitation here is dictated based on commercially tem from a drop in temperature of five of the blue available alloys capable of operating under the lines. Next, focus on line “6.” For a temperature conditions demanded by the AF cycle. A detailed rise of five blue lines, notice how much more stepwise explanation of the thermodynamic AF enthalpy is created in the system. One of the cycle (Figure F-8) is as follows:

42 Enthalpy and temperature are similar concepts, but enthalpy is y A-B: Shaft-driven wheel pump of recycled CO₂ a true measure of the usable energy that goes into and out of to circa 110 bar pressure a system. For example, a certain amount of heat (enthalpy) is needed to take water from room temperature up to just below the boiling point. Yet, seven times that amount of heat (enthalpy) is y B-C: Heating of recycled CO₂ (45% propor- required to take water from just below the boiling point to just tion) and oxidant stream in recuperative heat over the boiling point. Despite that massive amount of heat, the temperature of water barely changed. Yes, a watched pot really exchanger (stage 1 and 2) recovering low grade does not boil! heat from turbine exhaust flow

F-24 MEETING THE DUAL CHALLENGE CCUS Artist ______Date ______AC ______BA ______

1000 -40 -20 0 20 40 60 80 100 120 160 200 250 300 350 400 500 600 700 800 900 1000 1100 1200 1300 -2.00 -1.75 -1.50 -1.25 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 6. ADDITIONAL HEAT FUEL INPUT 0.75 E B C D

5. PUMP 7. HEAT EXCHANGER 1. COMBUSTOR 1.00 100 A H 5. COMPRESSOR

2. TURBINE G F 1.25

0 25 50 75 4. WATER SEPARATOR 3. HEAT EXCHANGER PRESSURE (BAR) 100 10 1.50

––– TEMPERATURE (°C) ––– VAPOR FRACTION (%) 1.75 ––– ENTROPY (KJ/KG-K) 1 -400 -300 -200 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 SPECIFIC ENTHALPY (KJ/KG) Source: 8 Rivers Capital, LLC. Pressure-Enthalpy Diagram of the Allam-Fetvedt Cycle FigureFigure F-8. F-8: Pressure-Enthalpy Diagram of the Allam-Fetvedt

y C-D: Heating of recycled CO₂ and oxidant Toshiba for the turbine and combustor engineer- stream in recuperative heat exchanger (stage 3) ing program, then with The Shaw Group (now recovering McDermott) invested $50M in 2012, followed by Exelon’s $100M in 2014, and in October of y D-E: Primary combustor heat input from oxy- 2018 Oxy Low Carbon Ventures, Occidental combustion and sCO₂ recycle flow up to tur- Petroleum’s venture arm dedicated to reducing/ bine inlet eliminating emissions, invested an undisclosed y E-F: Turbine expansion work output from circa sum. The partnership has provided the fund- 300 bara to 30 bara ing necessary to build and operate a 50MWth NET Power test facility in La Porte, Texas, and y F-G: Cooling of turbine exhaust (predominantly to begin commercial deployments happening CO₂/H O vapor) in recuperative heat exchanger 2 now. Construction of this first-of-a-kind proj- (stages 3, 2, and 1) ect began in March 2016 and was completed in y G-H: Multi-stage compression of recycle CO₂ December 2017. The facility completed commis- to required pump inlet pressure sioning in April 2018, with first fire occurring in May, and combustor testing successfully con- y H-A: Aftercooler. cluded in August. The completion of combustor testing proved basic feasibility, operability, and B. Planned Work with Allam-Fetvedt safety of the combustor and the fundamental Cycle – NET Power Allam-Fetvedt cycle itself. Full system tests are currently ongoing. In 2009, 8 Rivers Capital, a technology devel- opment firm set out to develop an idea for a new The first stage of testing at the demonstra- type of clean coal power plant. In 2011, 8 Rivers tion facility utilized the full cycle in addition to and NET Power entered into an agreement with a specially designed commercial-scale combustor

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-25 Technology/ Description Organization Award Project

Phase- Using special ionic liquids (ILs) to remove CO2 from the gas exhaust of coal-fired power plants. University of $2,559,562 Changing Notre Dame New class of ILs that are solid at room temperature and change to liquid when they bind to CO2. Ionic Liquids Upon heating, the CO2 is released for storage, and the ILs re-solidify and donate some of the heat generated in the process to facilitate further CO2 release.

Hybrid Hybrid approach to capture CO2. University of $1,516,908 Solvent- Kentucky CO2 is removed as flue gas is passed through an aqueous ammonium-based solvent. Membrane CO Capture Carbon-rich solution from the CO2 absorber is passed through a membrane that is designed to 2 selectively transport the bound carbon, enhancing its concentration on the permeate side. Combining the best of both membrane- and solvent-based carbon capture technologies.

Gelled Ionic Using a membrane made of a gelled IL to capture CO2 from the exhaust of coal-fired power plants. Colorado $3,650,557 Liquid-Based The membranes are created by spraying the gelled ILs in thin layers onto porous support structures University Membranes using a specialized coating technique. Boulder

The new membrane is highly efficient at pulling CO2 out of coal-derived flue gas exhaust while restricting the flow of other materials through it. Design involves few chemicals or moving parts. More mechanically stable than current technologies.

The team is now working to further optimize the gelled materials for CO2 separation and create a membrane layer that is less than 1 micrometer thick.

Metal Organic Identification of the best MOFs for use in capturing CO2 from the flue gas of coal-fired power plants. University $4,961,298 Framework Use of high-throughput instrumentation to analyze nearly 100 materials at a time, screening them for of California Research Berkeley the characteristics that optimize their ability to selectively adsorb CO2 from coal exhaust. The model predicts a significant decrease in parasitic energy penalty from 30% for traditional processes to 15% for an optimized MOF. UC Berkeley also demonstrated scalability of the optimized adsorbent to over 300g and prepared a pelletized form that is suitable for testing in fixed bed reactors. Synthetic A synthetic catalyst is designed with the same function as carbonic anhydrase, an enzyme in the Lawrence $3,632,000 Catalysts for human lungs that helps to separate CO2 from the blood. The catalyst can be used to quickly capture Livermore CO2 Storage CO2 from coal exhaust, just as the natural enzyme does in our lungs. National Development of encapsulating chemical solvents in permeable microspheres that will greatly increase Laboratory the speed of binding of CO2. Composite Development of an enhanced membrane by fitting MOFs, into hollow fiber membranes. Georgia Tech $998,928 Membranes for Research Analyzing MOFs based on their permeability and selectivity toward CO2. CO Capture Corporation 2 The composite membrane would be highly stable, withstanding the harsh gas environment found in coal exhaust.

CO2 Capture Development of a unique CO2 capture process in which a liquid absorbent changes into a solid upon GE $3,692,967 with Liquid- contact with CO2. to-Solid Once in solid form, the material can be separated and the CO2 can be released for storage by heating. Absorbents Upon heating, the absorbent returns to its liquid form, where it can be reused to capture more CO2. The approach is more efficient than other solvent-based processes because it avoids the heating of extraneous solvents such as water. Better Development of new and efficient forms of enzymes known as carbonic anhydrases. Codexis $4,657,045 Enzymes Carbonic anhydrases are common and are among the fastest enzymes, but they are not robust enough for Carbon to withstand the harsh environment found in the power plant exhaust steams. Capture The enzymes’ properties will be modified to withstand high temperatures and large swings in chemical composition.

Electro- Development of an electrochemical technology to capture CO2. Arizona State $3,471,515 chemical University This technology cuts both the energy requirements and cost of CO2 capture technology in half Carbon compared to today’s best methods. Capture This technology will increase the cost of electricity generation by 85%.

Syngas into An iron-based material along with a unique process are developed to convert syngas into electricity, H2, Ohio State $7,099,904 Fuel and/or liquid fuel with zero CO2 emissions. University

An iron-based oxygen carrier is used to generate CO2 and H2 from syngas in separate, pure product streams by means of a circulating bed reactor configuration.

The end products of the system are H2, electricity, and/or liquid fuel, all of which are useful sources of power that can come from coal or syngas derived from biomass.

Table F-6. Emerging CO2 Capture Technologies

F-26 MEETING THE DUAL CHALLENGE test stand to accommodate the testing of the information on the expected economics of its commercial-scale combustor in a recirculating 300 MWe natural gas plant. At the time of this fashion akin to the final design and operation study engineering work on several commercial of the overall cycle. The second stage, underway units globally were underway. at the time of this report, utilizes the full cycle design to accommodate integrated hot operation VII. U.S. DOE FUNDED PROJECTS of both the combustor and turbine for full process demonstration. The facility will likely be used Table F-6 gives descriptions of novel, trans- into the future as a test facility for various types formational projects that have been funded of equipment and sub-systems that have the by DOE, several of which are hybrid capture potential to increase the cycles performance. In approaches.43 addition to the demonstration plant, NET Power is developing a full commercial-scale offering and 43 Carbon Sequestration Leadership Forum. “Supporting Develop- ment of 2nd and 3rd Generation Carbon Capture Technologies: has completed a comprehensive pre-FEED (Front Mapping technologies and relevant test facilities,” Rev: 08 and End Engineering Design) to confirm preliminary final December 16, 2015. • • •

APPENDIX F – EMERGING CO2 CAPTURE TECHNOLOGIES F-27