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Title: CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems

Abstract

PNNL, Fluor Corporation and Queens University (Kingston, ON) successfully completed a three year comprehensive study of the CO2BOL water-lean solvent platform with Polarity Swing Assisted Regeneration (PSAR). This study encompassed solvent synthesis, characterization, environmental toxicology, physical, thermodynamic and kinetic property measurements, Aspen Plus™ modeling and bench-scale testing of a candidate CO2BOL solvent molecule. Key Program Findings The key program findings are summarized as follows: • PSAR favorably reduced stripper duties and reboiler temperatures with little/no impact to absorption column • >90% CO2 capture was achievable at reasonable liquid-gas ratios in the absorber • High rich solvent viscosities (up to 600 cP) were successfully demonstrated in the bench-scale system. However, the projected impacts of high viscosity to capital cost and operational limits compromised the other levelized cost of electricity benefits. • Low thermal conductivity of organics significantly increased the required cross exchanger surface area, and potentially other heat exchange surfaces. • CO2BOL had low evaporative losses during bench-scale testing • There was no evidence of foaming during bench scale testing • Current CO2BOL formulation costs project to be $35/kg • Ecotoxicity (Water Daphnia) was comparable between CO2BOL and MEA (169.47 versus 103.63 mg/L) • Full dehydration of the flue gas wasmore » determined to not be economically feasible. However, modest refrigeration (13 MW for the 550 MW reference system) was determined to be potentially economically feasible, and still produce a water-lean condition for the CO2BOLs (5 wt% steady-state water loading). • CO2BOLs testing with 5 wt% water loading did not compromise anhydrous performance behavior, and showed actual enhancement of CO2 capture performance. • Mass transfer of CO2BOLs was not greatly impeded by viscosity • Facile separation of antisolvent from lean CO2BOL was demonstrated on the bench cart • No measurable solvent degradation was observed over 4 months of testing – even with 5 wt% water present« less

Authors:
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1151840
Report Number(s):
PNWD-4432
DOE Contract Number:
DEAC0576RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Heldebrant, David J. CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems. United States: N. p., 2014. Web. doi:10.2172/1151840.
Heldebrant, David J. CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems. United States. doi:10.2172/1151840.
Heldebrant, David J. 2014. "CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems". United States. doi:10.2172/1151840. https://www.osti.gov/servlets/purl/1151840.
@article{osti_1151840,
title = {CO2-Binding Organic Liquids Gas Capture with Polarity-Swing-Assisted Regeneration Full Technology Feasibility Study B1 - Solvent-based Systems},
author = {Heldebrant, David J},
abstractNote = {PNNL, Fluor Corporation and Queens University (Kingston, ON) successfully completed a three year comprehensive study of the CO2BOL water-lean solvent platform with Polarity Swing Assisted Regeneration (PSAR). This study encompassed solvent synthesis, characterization, environmental toxicology, physical, thermodynamic and kinetic property measurements, Aspen Plus™ modeling and bench-scale testing of a candidate CO2BOL solvent molecule. Key Program Findings The key program findings are summarized as follows: • PSAR favorably reduced stripper duties and reboiler temperatures with little/no impact to absorption column • >90% CO2 capture was achievable at reasonable liquid-gas ratios in the absorber • High rich solvent viscosities (up to 600 cP) were successfully demonstrated in the bench-scale system. However, the projected impacts of high viscosity to capital cost and operational limits compromised the other levelized cost of electricity benefits. • Low thermal conductivity of organics significantly increased the required cross exchanger surface area, and potentially other heat exchange surfaces. • CO2BOL had low evaporative losses during bench-scale testing • There was no evidence of foaming during bench scale testing • Current CO2BOL formulation costs project to be $35/kg • Ecotoxicity (Water Daphnia) was comparable between CO2BOL and MEA (169.47 versus 103.63 mg/L) • Full dehydration of the flue gas was determined to not be economically feasible. However, modest refrigeration (13 MW for the 550 MW reference system) was determined to be potentially economically feasible, and still produce a water-lean condition for the CO2BOLs (5 wt% steady-state water loading). • CO2BOLs testing with 5 wt% water loading did not compromise anhydrous performance behavior, and showed actual enhancement of CO2 capture performance. • Mass transfer of CO2BOLs was not greatly impeded by viscosity • Facile separation of antisolvent from lean CO2BOL was demonstrated on the bench cart • No measurable solvent degradation was observed over 4 months of testing – even with 5 wt% water present},
doi = {10.2172/1151840},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2014,
month = 8
}

Technical Report:

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  • This report outlines the comprehensive bench-scale testing of the CO 2-binding organic liquids (CO 2BOLs) solvent platform and its unique Polarity Swing Assisted Regeneration (PSAR). This study outlines all efforts on a candidate CO 2BOL solvent molecule, including solvent synthesis, material characterization, preliminary toxicology studies, and measurement of all physical, thermodynamic and kinetic data, including bench-scale testing. Equilibrium and kinetic models and analysis were made using Aspen Plus™. Preliminary process configurations, a technoeconomic assessment and solvent performance projections for separating CO 2 from a subcritical coal-fired power plant are compared to the U.S. Department of Energy's Case 10 monoethanolamine baseline.
  • A new solvent-based CO2 capture process couples the unique attributes of non-aqueous, CO2-binding organic liquids (CO2BOLs) with the newly discovered polarity-swing-assisted regeneration (PSAR) process that is unique to switchable ionic liquids. Laboratory measurements with PSAR indicate the ability to achieve a regeneration effect at 75°C comparable to that at 120°C using thermal regeneration only. Initial measurements also indicate that the kinetic behavior of CO2 release is also improved with PSAR. Abstract cleared PNWD-SA-9743
  • This manuscript provides a detailed analysis of a continuous flow, bench scale study of the CO2BOL solvent platform with and without its Polarity Swing Assisted Regeneration (PSAR). This study encompassed four months of continuous flow testing of a candidate CO2BOL with a thermal regeneration and PSAR regeneration using decane antisolvent. In both regeneration schemes, steady state capture of >90 %CO2 was achieved using simulated flue gas at acceptable L/G ratios. Aspen Plus™ modeling was performed to assess process performance compared to previous equilibrium performance projections. This paper also includes net power projections, and comparisons to DOE’s Case 10 amine baseline.
  • A polarity swing-assisted regeneration (PSAR) process is disclosed for improving the efficiency of releasing gases chemically bound to switchable ionic liquids. Regeneration of the SWIL involves addition of a quantity of non-polar organic compound as an anti-solvent to destabilize the SWIL, which aids in release of the chemically bound gas. The PSAR decreases gas loading of a SWIL at a given temperature and increases the rate of gas release compared to heating in the absence of anti-solvent.
  • This paper describes an unusual solvent regeneration method unique to CO₂BOLs and other switchable ionic liquids; utilizing changes in polarity to shift the free energy of the system. The degree of CO₂ loading in CO₂BOLs is known to control the polarity of the solvent; conversely, polarity could be exploited as a means to control CO₂ loading. In this process, a chemically inert non-polar “antisolvent” is added to aid in de-complexing CO₂ from a CO₂-rich CO₂BOL. The addition of this polarity assist reduces temperatures required for regeneration of CO₂BOLs by as much as 76 °C. The lower regeneration temperatures realized withmore » this polarity change allow for reduced solvent attrition and thermal degradation. Furthermore, the polarity assist shows considerable promise for reducing regeneration energy of CO₂BOL solvents, and separation of the CO₂BOL from the antisolvent is as simple as cooling the mixture below the upper critical solution temperature. Vapour-liquid equilibrium and liquid-liquid equilibrium measurements of a candidate CO₂BOL with CO₂ with and without an antisolvent were completed. From this data, we present the evidence and impacts of a polarity change on a CO₂BOL. Thermodynamic models and analysis of the system were constructed using ASPEN Plus, and forecasts preliminary process configurations and feasibility are also presented. Lastly, projections of solvent performance for removing CO₂ from a sub-critical coal fired power plant (total net power and parasitic load) are presented with and without this polarity assist and compared to DOE’s Case 10 MEA baseline.« less