Determining alkalinity, carbon loading, and degradation of aqueous amine in CO2 capture processes using heuristic methods
Not Available
Irvin, Bradley D. (ORCID:0009000442514613)↗
Engineering topics
Liu, Kunlei
Publications and source records attributed to Liu, Kunlei.
Life cycle assessment of charge carrier mediated electrocatalytic reduction of carbon dioxide to formic acid
Not Available
Matin, Naser S.↗
Ash Fouling Free Regenerative Air Preheater for Deep Cyclic Operation
The University of Kentucky (UKy) project titled “Ash Fouling Free Regenerative Air Preheater for Deep Cyclic Operation”, DE-FE0031757, was conducted from 8/15/2019 to 8/14/2024 in two Budget Periods. Other participants included PPL Corporation and Black Dragon Double Boiler. The overall goal was to investigate the proposed self-cleaning technology to achieve ash fouling free air preheater operation in a coal-fired power plant, especially during deep cycling. All project deliverables, milestones, and success criteria were met. UKy obtained the following scientific findings. • Temporary and periodic high temperature of heating elements (450 ~ 500 °F) can prevent ash accumulation and maintain air preheater free of clogging. • The ash samples analysis and unit operation provide solid evidence of ABS formed during low load with SCR ammonia slip being the major cause of ash accumulation, and air preheater clogging can be prevented by raising the heating element temperature up to 450 °F~ 500 °F at which ABS is decomposed. • In-situ self-cleaning can be controlled by monitoring temperature and/or presetting fixed number of cleanings per day. Both approaches in pilot testing show positive results for maintaining an ash free state for the air preheater. • Temperature criteria (cold end or gas outlet temperature) for entering self-cleaning service is critical to balance the number of cleaning cycles with maintaining the ash level. • Temperature criteria (cold end or gas outlet temperature) for exiting self-cleaning service is critical to balance the duration of the cleaning cycles with maintaining the ash level.
01 COAL, LIGNITE, AND PEAT↗
Decoupling Charge Carrier Electroreduction and Enzymatic CO 2 Conversion to Formate Using a Dual-Cell Flow Reactor System
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Examining the Reactions of Ethanolamine’s Thermal Degradation Compounds in Carbon Capture through 1 H NMR and 13 C NMR
In amine scrubbing carbon capture, concerns about amine solvent degradation include whether it can affect the ability of the solvent to capture CO 2 . This study examines the interactions between the three most reported monoethanolamine (MEA) thermal degradation compounds namely, oxazolidine-2-one (OZD), N-(2-hydroxyethyl)-ethylenediamine (HEEDA), and N-(2- hydroxyethyl)-imidazoline-2-one (HEIA) with CO 2 in the presence and absence of MEA. We compared 1 H NMR, 13 C NMR, and heteronuclear single-quantum coherence (HSQC) NMR for neat OZD, HEEDA, and HEIA samples with CO 2 -loaded samples to observe changes in protonation and unique carbamate species formation. We found that OZD and HEIA did not directly react with CO 2 or undergo proton shifting based on our comparison of the neat OZD and HEIA samples with CO 2 -loaded spectra. However, we observed that the OZD can protonate when sparged with CO 2 in the presence of MEA, which suggests that the OZD acts as an intermediate. The NMR spectra for HEEDA indicated that HEEDA directly reacts with CO 2 at both amino groups and can protonate. In the presence of MEA, HEEDA and MEA can act like a solvent blend, resulting in multiple carbamates forming within the solvent. The neat HEIA spectrum, compared with CO 2 -loaded HEIA spectra, revealed similar results as OZD, where it does not react with CO 2 or protonate directly. However, HEIA does not protonate in the presence of MEA. These degradation compound reactions can increase the number of general equilibrium reactions during carbon capture and impact the model MEA solvent. This work helps provide a more complete picture of the reactions as the solvent degrades. Although this study examines CO 2 effects on thermal degradation products for MEA, other amines such as piperazine or 1- amino-3-propanol will degrade, and the degradation may speciate similarly with CO 2 . Furthermore, this study can impact and improve process models by assessing the degradation compounds’ reactions with CO 2 and potentially incorporating them into the model based on a neat solvent.
20 FOSSIL-FUELED POWER PLANTS↗
Development and Characterization of Densified Biomass-plastic Blend for Entrained Flow Gasification (Final Technical Report)
Supported by the U.S. DOE NETL Award DE-FE0032043, this project was a collaborative effort. Project participants included the University of Kentucky Institute for Decarbonization and Energy Advancement (UK IDEA), Biosystems and Agricultural Engineering department (UK BAE), and Wabash Valley Resources, LLC. The goal of this final technical project report is to comprehensively summarize the work conducted on project DE-FE0032043. In accordance with the Statement of Project Objectives (SOPO), the University of Kentucky (UK) (Project Prime Recipient) has developed and studied a biomass/plastic fuel with a hydrophobic surface area less than 10 m 2 /m 3 that is suitable for oxygen-blown entrained flow gasification with slurry feed. The project involved the utilization of an existing thermogravimetric analysis (TGA)-mass spectrometer (MS), 1.5” drop tube furnace, 1 ton per day (TPD) coal gasifier, and high-pressure extruder operated at UK. The pilot-scale production of blended material was done at the Polymers Technology Center in Charlotte, North Carolina. Parametric testing and solid fuel blend slurry performance validation was completed using the UK entrained flow gasifier with multiple opposed burners to narrow the major near-term technical gaps that impede gasification of biomass and carbonaceous mixed wastes such as plastics in order to achieve net-negative CO 2 emissions. Project results validated the UK approach to address the major technical challenges on the biomass/plastic pretreatment and gasification. Previously, this has been limited in application to fluidized-type or moving bed-type gasifiers due to the high-water uptake of porous biomass containing hydroxyl groups during the conventional slurry preparation, resulting in a highly viscous, un-pumpable slurry. The biomass pretreatment with plastic developed for this project demonstrates advantages in cost and flexibility, which include: 1) the development of a blended solid fuel slurry with 55-60 wt% solids and comparable heating value to 100% coal-based water slurry; 2) the collection of gasification kinetic data and identification of preliminary operating conditions by performing thermogravimetric analysis, gasification experiments by using a 1.5” drop tube furnace; and finally 3) the demonstrated gasification of the blended solid fuel in the UK entrained flow gasifier with a long-lasting stable solid fuel blend slurry, dataset detailing operating conditions, and characterization of slag phase formation and solidification. The lab-scale data and experience obtained during this project encourages the development of technologies and commercial approaches to enable a hydrogen-based energy economy while achieving net-negative CO 2 emissions through gasification of coal, biomass, and carbonaceous mixed wastes such as plastics.
01 COAL, LIGNITE, AND PEAT↗
Optimizing Direct Air Capture Solvents to Minimize Energy Consumption of CO 2 Release in a Carbonate Electrolyzer
Addressing climate change by carbon management is critical to achieving the goal of net zero carbon emissions by 2050. In this work, we examined the electrochemically-driven recovery of CO 2 during alkaline solvent regeneration for solvent-based direct air capture. A mathematical model was developed by incorporating carbonate chemistry with water electrolysis to predict the energy consumption per unit of CO 2 released. The predicted results were consistent with the experimental data, in which the experimental work was achieved by characterizing alkalinity and carbon loading values of solvent collected from a flow carbonate electrolyzer. Through this study, we learned that minimizing the energy expended on CO 2 release can be achieved by using an anolyte with a lower alkalinity, increasing the electric charge input to the electrolyzer, and reducing the ohmic resistance of the electrolyzer. Furthermore, using a supporting electrolyte, e.g., Na 2 SO 4 in the present work, effectively compensates for the higher ohmic resistance from using an anolyte with a lower alkalinity.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Electrochemically Regenerated Solvent for Direct Air Capture with Co-generation of Hydrogen at Bench-scale
The goal of this final project report is to summarize the work conducted on project DE-FE0032125. In accordance with the Statement of Project Objectives (SOPO), the University of Kentucky Institute for Decarbonization and Energy Advancement (UK IDEA) (Recipient) developed an intensified process to capture CO 2 from ambient conditions (415 ppm CO 2 ). The process combines low-temperature solvent-aided membrane capture with electrochemically-mediated solvent regeneration to simultaneously capture ambient CO 2 while regenerating the solvent. The technology employs only two primary units, a regenerator and an absorber/contactor, while generating high purity hydrogen as a co-product that can be sold, used for energy storage, or cost-saving depolarization of the direct air capture (DAC) system during the grid peak demand, allowing for flexible operation. Since the technology is powered directly by DC electricity, it can seamlessly tie in with power sources like solar cells without the need for AC/DC converters, therefore allowing for a remote operation to further mitigate greenhouse gas generation toward deploying a negative carbon emissions technology that is completely decoupled from the carbon emissions from the power source for the DAC unit. The completion of the project results in significant progress toward the Department of Energy’s (DOE’s) goal of advancing lab and bench-scale DAC systems to a sufficient maturity level that can justify their continued scale-up through the verification testing of the electrochemically regenerated solvent system for DAC with co-generation of hydrogen at bench-scale. The technology addressed the complexities of incumbent DAC systems by demonstrating at ambient conditions (1) low gas-side pressure-drop facile CO 2 capture via an intensified membrane absorber with in-situ regenerated hydroxide as capture solvent, (2) multi-functional electrochemical regenerator for hydroxide regeneration, CO 2 concentration and hydrogen production at less than 3 V, and (3) stable DAC performance including >90% capture with air influent at the CFM scale. The data from this project enables the completion of Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA). TEA and LCA demonstrate the potential of the proposed electrochemical solvent-based process to be a viable DAC option. The analysis did not identify any obvious concern for the bench-scale operation and no apparent barriers to implementing UK IDEA carbon capture and solvent regeneration system at a larger scale.
08 HYDROGEN↗
Copper-Doped Tin Oxides Supported on Mesoporous Carbon Xerogel for Boosting the Electrochemical Reduction of CO 2 to Formate in Bicarbonate Solution Coupled with CO 2
The electrochemical reduction of CO 2 into valuable products at mild reaction conditions and using cheap renewable electrical energy are goals to sustain a low-carbon economy. Among the various CO 2 reduction reaction products, formic acid (FA) has received significant attention because of its low Gibbs free energy input requirement and the simple reduction reaction involving the transfer of 2 electrons and 2 protons. In this work, a copper-doped tin oxide catalyst supported on a mesoporous carbon xerogel was shown to enhance the electrochemical reduction of CO 2 to formate in a bicarbonate solution coupled with CO 2 . We observed that the synergistic SnCu oxides enhance the selectivity toward formate from 58.6% for Sn oxide and 28.7% for Cu oxide to over 71.2% for the SnCu oxides. The observed rate of formate production with SnCu oxide was 2.8 times higher compared to the rate of Cu oxide and about 1.5 times higher than with the Sn oxide catalyst. Our results reveal that selectivity for formate comes partly from the electrolysis of the bicarbonate solution and partly from continuous CO 2 gas purged into the solution. The contribution from the electrolysis of bicarbonate solution ranges from 15% to 40% when the concentration of bicarbonate solution ranges from 100 mM to 1 M. Chronoamperometric measurements for stability revealed that Cu oxide and Sn oxide showed stable current density for less than 30 h while under the same conditions, the stable current density was observed for more than 50 h with SnCu oxide catalyst. Additionally, the selectivity toward formate increased by 6% when the reactor pressure was increased from near ambient pressure to 4 psig. Our lab-scale electrochemical cell with SnCu oxide supported on the mesoporous carbon xerogel enhances the CO 2 solubility, minimizes the precipitation of salts that can degrade the catalytic performance, and suppresses the competitive hydrogen evolution reaction, demonstrating the feasibility of using our catalyst and system for the electrochemical conversion of CO 2 into formate with high selectivity, productivity, and stability. Furthermore, this could have significant implications for the mitigation of CO 2 emissions and the development of a sustainable chemical industry.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Fog and Froth-based Post Combustion CO 2 Capture in Fossil Fuel Power Plants
The University of Kentucky (UK) project titled “Fog+Froth-Based Post-Combustion CO 2 Capture in Fossil Fuel Power Plant”, DE-FE0031733, was conducted from 5/1/2019 to 12/31/2023 in two Budget Periods (BPs), with BP1 from 5/1/2019 to 1/31/2021 and with BP2 from 2/1/2021 to 12/31/2023. The overall goal is to reduce the CO 2 capture capital and operating cost by reducing the absorber size. Other participants included Industrial Climate Solutions, Inc. (ICSI), ALL4 and NexantECA. All project deliverables, milestones, and success criteria were met. Scaled-up demonstration of the compact absorber is planned and two specific aspects of the project demonstration, the solvent spray and the low absorber bottom packing temperature, have been incorporated into the overall UK CO 2 capture process which is on the road to large scale verification and commercialization.
01 COAL, LIGNITE, AND PEAT↗
Compact absorption column for CO2 capture
An acid gas absorber includes a co-current flue gas-lean solution section and a packed counter-current flue gas-liquid phase section useful in a method of capturing an acid gas from flue gas in a more efficient and cost effective manner.
Liu, Kunlei↗