Global CO2 emissions are increasing at about a 1.5% rate per year. Fossil fuel-based plants are one of the main contributors to this rise. In the power generation industry, fossil fuel plants are dominant, and many plants are under development. In this study, a natural gas combined cycle (NGCC) power plant with postcombustion capture using a leading water-lean solvent is considered. For optimal design and operating schedule, large-scale dynamic optimization is undertaken for net present value (NPV) optimization. The first principle dynamic model of NGCC is developed, including a model of the highly efficient H-class gas turbines. For computational tractability of the dynamic optimization problem, a reduced-order model is developed by using the Hankel singular value decomposition. A water-lean solvent, N-(2-ethoxyethyl)-3-morpholinopropan-1-amine, is used for carbon capture. A model of the capture system is developed in Aspen Plus, which is used to develop a reduced-order model by using ALAMO, a machine learning software. In addition, a reduced model of the CO2 compression system with a dehydration unit is also considered. The integrated system is used for NPV optimization by using the Python-based PYOMO platform. The PCC process is analyzed for three configurations-conventional packed bed, rotating packed bed (RPB), and a combination of RPB and direct contact cooler. The NPV optimization is performed for 14 regional markets by considering year-long clustered and continuous locational marginal price data with a 1 h interval. Optimization results show that the PCC can achieve 90% CO2 capture with a positive NPV for six regions. Sensitivity studies conducted by using the PCC configurations indicate that the process is economically feasible for 9 regions out of 14 regional electricity markets with NPV values in the range of 33-540 $MM.

Water-lean solvents, like N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (EEMPA), show promise for postcombustion carbon capture, offering up to 36 and 25% energy and cost savings compared to 30 wt % MEA for a coal-fired power plant. Due to the increasing reliance on natural gas combined cycle (NGCC) power plants in the US, this study provides a conceptual design-level economic analysis of using water-lean solvents to capture 90-99.8% CO2 from NGCC flue gas. The higher capture rates correspond to resulting CO2 concentrations of <400 ppmv, which can be considered as "negative" emissions. The results indicate that EEMPA can achieve capture rates as high as 99.8% and an estimated minimum cost of $53.7/tonne CO2 (in 2018 U.S. dollar) at 90% capture. When applied as a negative emission technology with a postcapture exhaust gas CO2 concentration lower than 400 ppm, EEMPA proved economically attractive compared to direct-air capture technologies.

N-(2-ethoxyethyl)-3-morpholinopropan-1-amine, also known as EEMPA, has recently been developed as a post-combustion capture CO2 solvent. In this application, EEMPA can operate as a water-lean solvent, containing less than 5 wt.% H2O, without a diluent component to manage viscosity. EEMPA may be able to achieve competitive specific reboiler duties (less than 2.5 GJ/tonne CO2 captured) and has several positive characteristics, including miscibility with water, low vapor pressure, and good thermal and oxidative stability. This paper reports initial data from an on-going test campaign in the Pilot Solvent Test Unit (PSTU) at the National Carbon Capture Center. The primary objective of this campaign is to measure the performance of the solvent at the engineering scale on both coal-relevant and natural gas flue gases. Preparations for the test and modifications to the PSTU to accommodate water-lean operation are discussed. Capture rates above 90% have been achieved, including periods above 95% capture. Water content was systematically varied from below 1 wt.% to above 10 wt.% without operational issues although peak solvent viscosity exceeded initial expectations. An unexpected fog has been observed in the regenerator vessel across most operating conditions.

Here we demonstrate the proof-of-concept for microchannel reactive distillation for alcohol-to-jet application: combining ethanol/water separation and ethanol dehydration in one unit operation. Ethanol is first distilled into the vapor phase, converted to ethylene and water, and then the water co-product is condensed to shift the reaction equilibrium. Process intensification is achieved through rapid mass transfer-ethanol stripping from thin wicks using novel microchannel architectures-leading to lower residence time and improved separation efficiency. Energy savings are realized with integration of unit operations. For example, heat of condensing water can offset vaporizing ethanol. Furthermore, the dehydration reaction equilibrium shifts towards completion by immediate removal of the water byproduct upon formation while maintaining aqueous feedstock in the condensed phase. For aqueous ethanol feedstock (40%w), 71% ethanol conversion with 91% selectivity to ethylene was demonstrated at 220 degrees C, 600 psig, and 0.28 h-1 wt hour space velocity. 2.7 stages of separation were also demonstrated, under these conditions, using a device length of 8.3 cm. This provides a height equivalent of a theoretical plate (HETP), a measure of separation efficiency, of 3.3 cm. By comparison, conventional distillation packing provides an HETP of 30 cm. Thus, 9.1x reduction in HETP was demonstrated over conventional technology, providing a means for significant energy savings and an example of process intensification. Finally, preliminary process economic analysis indicates that by using microchannel reactive distillation technology, the operating and capital costs for the ethanol separation and dehydration portion of an envisioned alcoholto-jet process could be reduced by at least 35% and 55%, respectively, relative to the incumbent technology, provided future improvements to microchannel reactive distillation design and operability are made. (c) 2024 Published by ELSEVIER B.V. and Science Press on behalf of Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences.

Counter-current chromatography (CCC) is capable of unique elution modes that isolate analytes using the movement of the stationary phase in addition to moving the mobile phase. These modes include elution-extrusion CCC (EECCC) and dual-mode CCC (DM CCC) that are not possible in traditional solid-liquid chromatography systems. Although EECCC and DM CCC are widely used to recover highly retained components, to our knowledge, optimizing the elution process in these modes with predictive models has not been reported. To address this gap, we developed a predictive model for CCC dubbed the Cell Utilized Partitioning (CUP) model. The CUP model accurately predicts the effluents of multicomponent separations in EECCC and DM CCC modes when compared to experimental data. Furthermore, CUP model simulations were extended to investigate the influence of operating and intrinsic parameters on the yield and productivity, and to compare the separation performances of EECCC and DM CCC in various conditions. The results demonstrate that low distribution constants, usually a K-D less than 1, and a selectivity > 1.3, under specific flowrate ranges, increase both productivity and yield. From these results, generalized optimization and scaleup guidelines are proposed that can apply to research settings and to industrial processes to maximize preparative CCC performance.

Separation technologies currently used in U.S. manufacturing industries are estimated to account for more than 20% of plant energy consumption. However, accurately determining the impact of new separation technology solutions can sometimes be difficult, especially when evaluating a slate of new candidate separation technologies, each of which has its own separation performance, energy demand, and capital cost. In these cases, a typical approach is to assess each new separation technology by collecting performance and cost information and then using that information to develop a techno-economic analysis to identify overall benefits. While this approach is thorough, it can be time consuming and can hinder reaching a critical understanding of the potential of a given separation challenge, especially when there is no known solution. To address these issues, we developed an assessment methodology, using industrial screening processes, that can be used to better understand the potential impacts of addressing a given separation challenge. This paper presents an overview of our separation challenge stream assessment methodology. The methodology involves defining an “ideal” separator and deriving the associated minimum separation energy. The “ideal” separator represents the most optimistic outlook of a given opportunity so the maximum impact from existing and not-yet-developed solutions can be assessed. Using established biorefinery models, we applied the methodology to 10 different separation challenge streams from two different biomass conversion platforms to identify the type of information that can be obtained. Three of the ten challenge streams assessed had maximum possible cost savings predictions >20%, and associated reductions in process energy carbon intensity ranging from 0 to 54%. Two streams had cost and energy savings potential that were < 5%. Some of the opportunity drivers from the various assessments include higher product yields, reduction or elimination of downstream equipment, new co-products, and cost savings associated with raw materials and energy consumption. The information from these assessments can help guide the selection or development of new separation technology solutions based on the various potential factors that drive the projected benefits.

Water-lean solvents can significantly reduce the energy penalty of post-combustion carbon capture associated with water vaporization during solvent regeneration. PNNL’s current leading CO2BOL derivative, EEMPA is a promising post-combustion carbon capture because of its low energy- and cost-penalty (19% cheaper than NETL’s baseline technology) that is currently being scaled up for a 0.5 MW scale testing at the National Carbon Capture Center on coal and natural gas exhaust. While EEMPA is continues to advance in its testing, there are dozens of other CO2BOL derivatives have been identified through our previous molecular modelling studies, which may have the desired properties for post-combustion carbon capture. Here, we assess two new CO2BOL derivatives along, presenting their synthesis, property testing and process modeling in addition to results from 40 hr continuous-flow testing and comprehensive techno-economic analysis.

PNNL’s most recent single-component diamine CO2BOL derivative, 2-EEMPA, is an attractive post- combustion carbon capture solvent. This solvent can be configured to achieve regeneration energies as low as 2.0 GJ/tonne CO2 when configured with advanced heat integration, and total capture costs as low as $47.1/tonne CO2 when using a two-stage flash configuration. 2-EEMPA has been shown to be chemically durable, exhibits little foaming, and maintains a steady-state water loading of 1.6 wt%, as demonstrated on continuous flow testing with simulated flue gas. 2-EEMPA is potentially capable of thermally cracking heat-stable salts from NOx and SOx using PNNL’s polarity-swing assisted regeneration process. Building off of the promising behaviour of 2-EEMPA we conclude that by focusing future research areas on remaining cost-of-capture drivers, further improvements to water- lean formulations could be possible.

Aqueous amines-based absorption is the most mature and scalable technology for post-combustion carbon capture, but subject to high energy and capital investment costs. Water-lean solvents, with associated advanced process configurations, show promise of significantly reducing both energy and capital costs via lower solvent recirculation and lower water condensation and vaporization. Even though advanced process configurations have been intensively studied for aqueous amines, few discussions can be found in the open literature for water-lean solvents. In order to fill the gap, the present study focuses on the process designs towards lower carbon capture cost enabled by water-lean solvents. N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (EEMPA), a single-component water-lean solvent, was selected as an archetypical water-lean solvent. A property package was developed for the H2O−CO2-EEMPA system based on experimental data. Process models were developed in Aspen Plus for 90% CO2 capture in a 550 MW supercritical pulverized coal power plant, with optimal operating conditions determined by sensitivity studies. Techno-economic analyses were performed to compare seven process configurations: simple stripper, two-stage flash, lean vapor compression, inter-heated column, advanced flash stripper, low-pressure steam heater, and advanced heat integration. The results show a two-stage flash configuration, has a carbon capture cost of $47.1/tonne CO2 (in 2011 US dollars), about 19% lower than the industrial benchmark, Cansolv. While considerable capture cost reductions have been proven for aqueous amine using lean vapor compressor and advanced flash stripper, those configurations were shown to have negligible impacts with water-lean solvents due to differences in solvent’s physical properties.

Electrocatalytic conversion is emerging as a potentially attractive low-cost approach to valorize biomass-derived streams. Conventional upgrading processes require moderate temperatures between 433 and 678 K, pressures of 14,000 kPa, and external sources of dihydrogen; however, the same upgrading reaction can be performed using electrochemical reactors and much lower temperatures and pressures (293 K and 101 kPa) and with no supplied hydrogen (H 2 ). 1-4 In this work, we evaluate the electrocatalytic conversion of aqueous waste and bio-oils generated during biomass liquefaction via hydrothermal liquefaction (HTL) and pyrolysis. Our work shows that the main biomass-derived compounds (carboxylic acids, alcohols, ketones, etc.) were successfully converted via electrocatalytic oxidation (ECO) into olefins, paraffins, and alcohols. 2, 5 Alternatively, the same compounds could not be upgraded via electrocatalytic hydrogenation (ECH) over a variety of noble and base metals, instead H 2 evolution was the preferred reaction. 1, 3 Figure 1 shows that the operation (electricity) cost can be offset by the sale of the excess H 2 generated (valued at >$2/kg H2 ) specially when operating at low full cell potentials (<4.5 V) and using low electricity cost (<¢4/kwh). 2 Additionally, a preliminary techno-economic analysis shows the capital cost associated with the integrated electrocatalytic process for the aqueous waste treatment and H 2 generation can be up to 80% lower than the combined cost for traditional thermal (e.g., gasification) and biological (e.g., anaerobic digestion) wastewater treatment, and H 2 generation (via natural gas steam reforming), and can lower the minimum fuel selling price (MFSP) by up to $0.84/GGE. References Andrews, E.; Lopez-Ruiz, J. A.; Egbert, J.; Koh, K.; Sanyal, U.; Miao, S.; Li, D.; Karkamkar, A.; Derewinski, M. A.; Holladay, J.; Gutiérrez, O. Y.; Holladay, J. D., Performance of Base and Noble Metals for Electrocatalytic Hydrogenation of Bio-Oil-Derived Oxygenated Compounds. ACS Sustainable Chem. Eng. 2020, 8 (11), 4407-4418. Lopez-Ruiz, J. A.; Qiu, Y.; Andrews, E.; Gutiérrez, O. Y.; Holladay, J. D., Electrocatalytic valorization into H2 and hydrocarbons of an aqueous stream derived from hydrothermal liquefaction. J. Appl. Electrochem. 2020, Accepted . Lopez-Ruiz, J. A.; Andrews, E. A.; Akhade, S. A.; Lee, M.; Koh, K.; Sanyal, U.; Yuk, S. F.; Karkamkar, A. J.; Derewinski, M. A.; Holladay, J.; Glezakou, V. A.; Rousseau, R.; Gutiérrez, O. Y.; Holladay, J. D., Understanding the role of metal and molecular structure on the electrocatalytic hydrogenation of oxygenated organic compounds. ACS Catal. 2019, 9 (11), 9964-9972. Lopez-Ruiz, J. A.; Sanyal, U.; Egbert, J.; Gutiérrez, O. Y.; Holladay, J., Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials. ACS Sustainable Chem. Eng. 2018, 6 (12), 16073-16085. Qiu, Y.; Lopez-Ruiz, J. A.; Sanyal, U.; Andrews, E.; Gutiérrez, O. Y.; Holladay, J. D., Anodic electrocatalytic conversion of carboxylic acids on thin films of RuO2, IrO2, and Pt. Appl. Catal. B-Environ. 2020, 277 , 119277. Snowden-Swan, L. J.; Hallen, R. T.; Zhu, Y.; Hart, T. R.; Bearden, M. D.; Liu, J.; Seiple, T. E.; Albrecht, K. O.; Jones, S. B.; Fox, S. P.; Schmidt, A. J.; Maupin, G. D.; Billing, J. M.; Elliott, D. C. Conceptual Biorefinery Design and Research Targeted for 2022: Hydrothermal Liquefaction Processing of Wet Waste to Fuels ; PNNL-27186. BM0108010; Pacific Northwest National Lab. (PNNL), Richland, WA (United States): 2017. Figure 1

Washington River Protection Solutions (WRPS) tested four types of chemical cartridges for use in air-purifying respirators (APR) and powered air-purifying respirators (PAPR). These tests were undertaken to determine the period of time that the cartridges would provide adequate performance1 for APRs and PAPRs used to protect workers when exposed to a mixture of Chemicals of Potential Concern (COPC) from vapors exiting the headspaces of Hanford BY-108 and BY-110 waste storage tanks. The Occupational Safety and Health Administration (OSHA) considers cartridge testing to be a valid approach for establishing cartridge change schedules.2 Testing commonly is applied in situations where mixtures of COPCs exist, and where other approaches, such as manufacturer recommendations and modeling, are less reliable. The tests were designed and conducted to assure measurement and/or control of the key variables OSHA identified as important to estimate the cartridge service life, including temperature, humidity, COPC concentration, breathing rate, and cartridge adsorption capacity. Cartridge tests were conducted over two days from February 23-25, 2018, using headspace vapors from Hanford tanks BY-108 and BY-110. Headspace vapors from the BY-108 tank were fed to the PAPR respirator cartridge test stand, while vapors from the BY-110 headspace were fed to the APR respirator cartridge test stand. Both the APR and PAPR test stands were developed by WRPS in collaboration with HiLine Engineering (Richland, Washington). Two different cartridges were assessed on each tank. Multipurpose APR cartridges—SCOTT 7422-SD1 and SCOTT 7422-SC1 (SCOTT Safety, Monroe, North Carolina)—were assessed for vapors from BY-110 using the APR cartridge test stand. Multipurpose PAPR cartridges—MSA OptiFilter TL (MSA Safety Inc., Pittsburgh, Pennsylvania) and 3M FR-57 (3M Company, Maplewood, Minnesota)—also were assessed for vapors from BY-108 over the same two days using the PAPR cartridge test stand. Sample media (i.e., sorbent tubes) were used to collect samples of the vapor stream entering and exiting the respirator cartridges, and the samples then were analyzed for COPC concentrations. Pacific Northwest National Laboratory was tasked with conducting an independent analysis of the analytical results and making recommendations based on the results for respiratory cartridge performance and service life. The key conclusions from the analysis are described below.

Washington River Protection Solutions (WRPS) conducted tests using two types of chemical cartridges for use in air purifying respirators to determine the period of time that the cartridges would provide adequate protection to worker when exposed to a mixture of Chemicals of Potential Concern (COPCs) from vapors emanating from the headspace of tank BY-108 on the Hanford Site. Pacific Northwest National Laboratory (PNNL) was tasked with conducting an independent analysis of the analytical results and making recommendations based on the results for respiratory cartridge performance and change schedules.

Between 2017 and 2018, 10 powered air-purifying respirator (PAPR) cartridge tests were performed on headspace vapors from three Hanford tanks (BY-108, SX-101, and SX-104) and two Hanford Tank Farm exhausters (AP in 2018 and AX in 2017). All tests were conducted under static conditions absent waste-disturbing activities in the subject tanks or tank farms. Multipurpose high-efficiency PAPR cartridges, MSA-TL (TL1) (MSA Safety Inc., Pittsburgh, Pennsylvania) and 3M FR-57 (TL2) (3M Company, Maplewood, Minnesota), were tested on each of the five tanks or exhausters. Out of 611 Chemicals of Potential Concern (COPCs), only ammonia and 2,5-dimethylfuran exhibited breakthroughs with outlet concentrations that were greater than 10% of their Occupational Exposure Limits (OEL). For 2,5-dimethylfuran, elevated concentrations found in blank tube samples made the elevated outlet measurements for this COPC questionable.

Washington River Protection Solutions (WRPS) conducted tests on two types of chemical cartridges for use in air-purifying respirators (APR) to determine the period of time that the cartridges would provide adequate performance1 for APRs used to protect workers when exposed to a mixture of Chemicals of Potential Concern (COPC) from vapors emanating from the headspace of tank SY-102 on the Hanford Site. The Occupational Safety and Health Administration (OSHA) identifies cartridge testing as a valid approach for establishing a cartridge change schedule. Testing is commonly applied in situations where mixtures of COPCs exist, and where other approaches, such as manufacturer recommendations and modeling, are less reliable. The tests were designed and conducted to assure measurement and/or control of the key variables OSHA identified as important to estimate cartridge service life, including temperature, humidity, COPC concentration, worker breathing rate, and cartridge adsorption capacity. Testing was conducted from July 8–10, 2016, on headspace vapors from Hanford tank SY-102 under static conditions2 fed to a respirator cartridge test stand developed by WRPS in collaboration with HiLine Engineering (Richland, Washington). Multipurpose respirator cartridges, SCOTT 7422-SD1 and SCOTT 7422-SC1 (SCOTT Safety, Monroe, North Carolina) were assessed on separate days. Sample media (sorbent tubes) were used to collect samples of the vapor stream entering and exiting the respirator cartridge and were subsequently analyzed for COPC concentrations. Pacific Northwest National Laboratory was tasked with conducting an independent analysis of the analytical results and making recommendations based on the results for respiratory cartridge performance and service life.

Washington River Protection Solutions (WRPS) conducted tests using two types of chemical cartridges for use in air-purifying respirators (APR) to determine the period of time that the cartridges would provide adequate performance1 for APRs used to protect workers when exposed to a mixture of Chemicals of Potential Concern (COPC) from vapors exiting the 702-AZ Primary Exhauster for the Hanford AY-AZ tank farms. Unlike prior cartridge testing on the 702-AZ Primary Exhauster, the recent tests were performed during a waste-disturbing event. The Occupational Safety and Health Administration (OSHA) identifies cartridge testing as a valid approach for establishing a cartridge change schedules [3]. Testing is commonly applied in situations where mixtures of COPCs exist, and where other approaches, such as manufacturer recommendations and modeling, are less reliable. The tests were designed and conducted to assure measurement and/or control of the key variables OSHA identified as important to estimate the cartridge service life, including temperature, humidity, COPC concentration, breathing rate, and cartridge adsorption capacity. Testing was conducted from February 10–11, 2017, on a slipstream from the 702-AZ exhauster fed to a respirator cartridge test stand developed by WRPS in collaboration with HiLine Engineering (Richland, Washington). Multipurpose respirator cartridges, SCOTT 7422-SD1 and SCOTT 7422-SC1 (SCOTT Safety, Monroe, North Carolina), were assessed on separate days. Sample media (sorbent tubes) and canisters (e.g., Summa) sampling were used to collect samples of the vapor stream entering and exiting the respirator cartridge and were subsequently analyzed for COPC concentrations. Pacific Northwest National Laboratory was tasked with conducting an independent analysis of the analytical results and making recommendations based on the results for respiratory cartridge performance and service life.