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A comprehensive evaluation of a recently developed water-lean amine-based solvent, namely N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (2-EEMPA), has been performed to analyze its post-combustion CO2 capture performance. This evaluation comprises (1) fundamental characterization of the solvent–CO2 interaction using vapor–liquid equilibria, kinetics and viscosity measurements; (2) process characterization of the CO2 capture performance as measured in a laboratory scale continuous flow system and via Aspen Plus® simulation using a flue gas simulant; as well as (3) a full techno economic analysis of the capture process at industrial scale with corresponding projections of critical metrics. This paper summarizes the many parts of this comprehensive evaluation and shows how the various parts come together to empower validated conclusions about its process performance. Notably, it is projected that this solvent can operate at a regeneration heat rate of 2.0 GJ per tonne CO2 for post-combustion capture, and at a total cost of capture of $50.6/tonne CO2. With further process optimization significant reductions in the capture cost are predicted.

We present here an overview of water-lean solvents that compares their projected costs and performance to aqueous amine systems, emphasizing critical areas of study needed to evaluate their performance against their water-based brethren. The work presented here focuses on bridging these knowledge gaps. Because the majority of water-lean solvents are still at the lab scale, substantial studies are still needed to model and assess their performance at full scales. This presents a significant challenge as each formulation has different physical and thermodynamic properties and behavior, and quantifying how these different properties manifest themselves in conventional absorber-stripper configurations, or identifying new configurations that are specific for a solvent's signature behavior. We identify critical areas of study that are needed, and our efforts (e.g. custom infrastructure, molecular models) to predict, measure, and model these behaviors. Such findings are critical for determining the rheology required for heat exchanger design; absorber designs and packing to accommodate solvents with gradient changes (e.g. viscosity, contact angle, surface tension), and stripper configurations without direct steam utilization or water reflux. Another critical area of research need is to understand the molecular structure of the liquid interface and bulk as a function of CO2 loading, and to assess whether conventional film theories accurately quantify solvent behavior, or if thermodynamic models adequately quantify activity coefficients of ions in solution. We conclude with an assessment of our efforts to aid in bridging the knowledge gaps in understanding water-lean solvents, and suggestions of what is needed to enable large-scale demonstrations to meet the United States Department of Energy's goals.

We present novel design strategies for reduced viscosity single-component, water-lean CO 2 capture organic solvent systems. Through molecular simulation, we identify the main molecular-level descriptor that influences bulk solvent viscosity. Upon loading, a zwitterionic structure forms with a small activation energy of ca 16 kJ/mol and a small stabilization of ca 6 kJ/mol. Viscosity increases exponentially with CO 2 loading due to hydrogen-bonding between neighboring Zwitterions. We find that molecular structures that promote internal hydrogen bonding (within the same molecule) and suppress interactions with neighboring molecules have low viscosities. In addition, tuning the acid/base properties leads to a shift of the equilibrium toward a non-charged (acid) form that further reduces the viscosity. Based on the above structural criteria, a reduced order model is also presented that allows for the quick screening of large compound libraries and down selection of promising candidates for synthesis and testing.

This paper investigates the CO2 and N2O absorption behavior in the water-lean gamma amino propyl (GAP)-1/TEG solvent system using a wetted-wall contactor. Testing was performed on a blend of GAP-1 aminosilicone in triethylene glycol at varied water loadings in the solvent. Measurements were made with CO2 and N2O at representative lean (0.04 mol CO2/mol alkalinity), middle (0.13 mol CO2/mol alkalinity), and rich (0.46 mol CO2/mol alkalinity) solvent loadings at 0, 5, 10, and 15 wt % water loadings at 40, 60, and 80 °C and N2O at (0.08–0.09 mol CO2/mol alkalinity) at 5 wt % water at 40, 60, and 80 °C. CO2 flux was found to be nonlinear with respect to log mean pressure driving force (LMPD). Liquid-film mass transfer coefficients (k′g) were calculated by subtracting the gas film resistance (determined from a correlation from literature) from the overall mass transfer measurement. The resulting k′g values for CO2 and N2O in GAP-1/TEG mixtures were found to be higher than that of 5 M aqueous monoethanolamine u...

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 (H2).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 H2 evolution was the preferred reaction.1, 3 Figure 1 shows that the operation (electricity) cost can be offset by the sale of the excess H2 generated (valued at >$2/kgH2) specially when operating at low full cell potentials (2 Additionally, a preliminary techno-economic analysis shows the capital cost associated with the integrated electrocatalytic process for the aqueous waste treatment and H2 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 H2 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

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.

This paper investigates CO2 absorption behavior in CO2BOL solvents by decoupling the physical and chemical effects using N2O as a nonreactive mimic. Absorption measurements were performed using a wetted-wall contactor. Testing was performed using a “first generation” CO2-binding organic liquid (CO2BOL), composed of an independent base and alcohol. Measurements were made with N2O at a lean (0.06 mol CO2/mol BOL) and rich (0.26 mol CO2/mol BOL) loading, each at three temperatures (35, 45, and 55 °C). Liquid-film mass transfer coefficients (kg′) were calculated by subtracting the gas film resistance-determined from a correlation from literature–from the overall mass transfer measurement. The resulting kg′ values for N2O in CO2BOLs were found to be higher than that of 5 M aqueous MEA under comparable conditions, which is supported by published measurements of Henry’s coefficients for N2O in various solvents. These results suggest that the physical solubility contribution for CO2 absorption in CO2BOLs is great...

CO2 capture from power generation with aqueous solvents remains energy intensive due to the high water content of the current technology, or the high viscosity of non-aqueous alternatives. Quantitative reduced models, connecting molecular structure to bulk properties, are key for developing structure–property relationships that enable molecular design. In this work, we describe such a model that quantitatively predicts viscosities of CO2 binding organic liquids (CO2BOLs) based solely on molecular structure and the amount of bound CO2. The functional form of the model correlates the viscosity with the CO2 loading and an electrostatic term describing the charge distribution between the CO2-bearing functional group and the proton-receiving amine. Molecular simulations identify the proton shuttle between these groups within the same molecule to be the critical indicator of low viscosity. The model, developed to allow for quick screening of solvent libraries, paves the way towards the rational design of low viscosity water-lean solvent systems for post-combustion CO2 capture. Following these theoretical recommendations, synthetic efforts of promising candidates and viscosity measurement provide experimental validation and verification.

Broad research is underway on developing transformational solvents that can capture of CO 2 from flue gas with lower energy compared to aqueous amines. Water-lean, or non-aqueous, solvents are being considered as a class of transformational solvents due to the prospect of lower energy duties by not having to heat and condense water. To date, little is known about the real world performance of water-lean solvent systems compared to commercial aqueous amine technologies, and whether or not they can utilize existing or at least similar processing infrastructure. This paper provides the key results from a comprehensive three-year study of the water-lean CO 2 -Binding Organic Liquids (CO 2 BOL) solvent platform coupled with Polarity-Swing Assisted Regeneration (PSAR). We present here thermodynamic, kinetic, and bench-scale data, followed by Aspen Plus projections of full-scale process performance for three CO 2 BOL/PSAR cases. This paper also provides discussions on materials performance and identifies viscosity as a critical property that most greatly limits the viability of water-lean solvent platforms. We provide results from a new effort spanning molecular modeling and synthesis and experimental testing to decipher the critical material properties needed to address this challenge. We conclude with implications for development of other water-lean solvent systems.

Anhydrous tertiary alkanolamines chemically react with CO2 and H2S, with greater selectivity for the latter. This is in direct contrast to aqueous amine-based solvent systems, which exhibit higher ...

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

The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.

Carbon capture and storage (CCS) is one of a suite of technology options that might play a significant role in reducing greenhouse gas emissions. However, outside of traditional enhanced oil and gas recovery operations with a well established business model, CCS project deployments are struggling with adoption of a federal or international climate policy driver appearing unlikely for the foreseeable future. As part of a feasibility study for an industrial CCS project at the Boise White Paper mill in Washington State, a business model and CCS system design was developed that provided financial surety for the project developers while recognizing that uncertainty in revenue forecasts for CO2 storage would persist for the foreseeable future. Key to the business model was installation of a new 37 MWe biomass-fueled power island at the plant that would replace antiquated boilers and that could still supply the necessary steam to run pulp and paper production operations when capturing CO2 emissions under favorable market conditions for monetizing CO2 storage credits. Under unfavorable market conditions, CO2 capture would be suspended and excess power generated from the plant would reduce external electrical energy purchases required for paper mill operations. The net CO2 reduction for the project versus current operations is 1.0 MMT of CO2 per year with the CCS system online, and 139 ktons per year with the CCS system offline due to reduced natural gas co-firing. So, both operational modes offered a significant net reduction in CO2 emissions. Based on assumptions regarding electricity and natural gas pricing, and CO2 storage revenue generated through an open market mechanism priced at $15 per metric ton CO2, the payback period for the project capturing 0.5 MMT/yr (62% of total CO2 production) was estimated at 6.7 years versus 7.4 years with the CCS system offline. Geologic storage was evaluated in the deep flood basalt formations that dominate the storage capacity in Eastern Washington. Sub-basalt sediments were also examined at the site to provide alternative or supplemental storage capacity in the event that storage in the basalt sequences did not prove technically or economically feasible.

We report the performance of multiple CO2 binding organic liquids (CO2BOLs) as solvent systems for post combustion gas capture. Alkanolguanidines and alkanolamidines are single component CO2BOLs that reversibly bind CO2 chemically as liquid zwitterionic amidinium/guanidinium alkylcarbonates. Select alkanolguanidines/alkanolamidines and guanidine/alcohol mixtures were tested for CO2 capacity and solvent lifetime. Solvent performance of these three CO2BOLs was assessed by batchwise CO2 uptake and release over multiple cycles. We report each CO2BOL's activity and solvent durability with and without water.

This manuscript provides a detailed analysis of a continuous-flow, bench-scale study of the CO2-binding organic liquid (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 a decane antisolvent. In both regeneration schemes, steady-state capture of >90% CO2 was achieved using simulated flue gas at reasonable liquid/gas (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, and comments on the viability of the CO2BOL solvent class for post-combustion CO2 capture.

Metal-organic frameworks (MOFs) have proved to be very attractive for applications including gas storage, separation, sensing and catalysis. In particular, CO(2) separation from flue gas in post-combustion processes is one of the main focuses of research among the scientific community. One of the major issues that are preventing the successful commercialization of these novel materials is their high affinity towards water that not only compromises gas sorption capacity but also the chemical stability. In this paper, we demonstrate a novel post-synthesis modification approach to modify MOFs towards increasing hydrophobic behaviour and chemical stability against moisture without compromising CO(2) sorption capacity. Our approach consists of incorporating hydrophobic moieties on the external surface of the MOFs via physical adsorption. The rationale behind this concept is to increase the surface hydrophobicity in the porous materials without the need of introducing bulky functionalities inside the pore which compromises the sorption capacity toward other gases. We herein report preliminary results on routinely studied MOF materials [MIL-101(Cr) and NiDOBDC] demonstrating that the polymer-modified MOFs retain CO(2) sorption capacity while reducing the water adsorption up to three times, with respect to the un-modified materials, via an equilibrium effect. Furthermore, the water stability of the polymer-functionalized MOFs is significantly higher than the water stability of the bare material. Molecular dynamic simulations demonstrated that this equilibrium effect implies a fundamental and permanent change in the water sorption capacity of MOFs. This approach can also be employed to render moisture stability and selectivity to MOFs that find applications in gas separations, catalysis and sensing where water plays a critical role in compromising MOF performance and recyclability.

This study examines how existing U.S. refining infrastructure matches in geography and processing capability with the needs projected from anticipated biofuels production. Key findings include:  a potential shortfall in both overall hydrotreating capacity and hydrogen production capacity in refineries to manage the conversion of certain bio-derived feedstocks having high oxygen contents;  a regional concentration of anticipated biofuel resources, placing added stress in particular refining regions (e.g. the Gulf Coast);  uncertainties surrounding the impact of bio-derived fuel intermediates on the refiner’s ability to meet product performance and product quantity demands, and the need for better and more comprehensive chemical composition information;  the need for considerably more data and experience on the behavior of projected biofuels feedstocks in refining processes (e.g. impacts on process performance and reliability);  and the need to examine the optimum capital investment locations for additional processing equipment. For example, whether it is better to further refine biofuels at the new production sites, in centralized biofuel "depots", or whether the existing refining facilities should be expanded to better handle a more 'raw' biofuel.

Carbon capture and sequestration (CCS) has the ability to dramatically reduce carbon dioxide (CO2) emissions from power production. Most studies find the potential for 70 to 80 percent reductions in CO2 emissions on a life-cycle basis, depending on the technology. Because of this potential, utilities and policymakers are considering the wide-spread implementation of CCS technology on new and existing coal plants to dramatically curb greenhouse gas (GHG) emissions from the power generation sector. However, the implementation of CCS systems will have many other social, economic, and environmental impacts beyond curbing GHG emissions that must be considered to achieve sustainable energy generation. For example, emissions of nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM) are also important environmental concerns for coal-fired power plants. For example, several studies have shown that eutrophication is expected to double and acidification would increase due to increases in NOx emissions for a coal plant with CCS provided by monoethanolamine (MEA) scrubbing. Potential for human health risks is also expected to increase due to increased heavy metals in water from increased coal mining and MEA hazardous waste, although there is currently not enough information to relate this potential to actual realized health impacts. In addition to environmental and human health impacts, supply chain impacts and other social, economic, or strategic impacts will be important to consider. A thorough review of the literature for life-cycle analyses of power generation processes using CCS technology via the MEA absorption process, and other energy generation technologies as applicable, yielded large variability in methods and core metrics. Nonetheless, a few key areas of impact for CCS were developed from the studies that we reviewed. These are: the impact of MEA generation on increased eutrophication and acidification from ammonia emissions and increased toxicity from MEA production and the impact of increased coal use including the increased generation of NOx from combustion and transportation, impacts of increased mining of coal and limestone, and the disposal of toxic fly ash and boiler ash waste streams. Overall, the implementing CCS technology could contribute to a dramatic decrease in global GHG emissions, while most other environmental and human health impact categories increase only slightly on a global scale. However, the impacts on human toxicity and ecotoxicity have not been studied as extensively and could have more severe impacts on a regional or local scale. More research is needed to draw strong conclusions with respect to the specific relative impact of different CCS technologies. Specifically, a more robust data set that disaggregates data in terms of component processes and treats a more comprehensive set of environmental impacts categories from a life-cycle perspective is needed. In addition, the current LCA framework lacks the required temporal and spatial scales to determine the risk of environmental impact from carbon sequestration. Appropriate factors to use when assessing the risk of water acidification (groundwater/oceans/aquifers depending on sequestration site), risk of increased human toxicity impact from large accidental releases from pipeline or wells, and the legal and public policy risk associated with licensing CO2 sequestration sites are also not currently addressed. In addition to identifying potential environmental, social, or risk-related issues that could impede the large-scale deployment of CCS, performing LCA-based studies on energy generation technologies can suggest places to focus our efforts to achieve technically feasible, economically viable, and environmentally conscious energy generation technologies for maximum impact.

This report documents the efforts taken to develop a preliminary design for the first commercial-scale CO2 capture and sequestration (CCS) project associated with biomass power integrated into a pulp and paper operation. The Boise Wallula paper mill is located near the township of Wallula in Southeastern Washington State. Infrastructure at the paper mill will be upgraded such that current steam needs and a significant portion of the current mill electric power are supplied from a 100% biomass power source. A new biomass power system will be constructed with an integrated amine-based CO2 capture plant to capture approximately 550,000 tons of CO2 per year for geologic sequestration. A customized version of Fluor Corporation’s Econamine Plus™ carbon capture technology will be designed to accommodate the specific chemical composition of exhaust gases from the biomass boiler. Due to the use of biomass for fuel, employing CCS technology represents a unique opportunity to generate a net negative carbon emissions footprint, which on an equivalent emissions reduction basis is 1.8X greater than from equivalent fossil fuel sources (SPATH and MANN, 2004). Furthermore, the proposed project will offset a significant amount of current natural gas use at the mill, equating to an additional 200,000 tons of avoided CO2 emissions. Hence, the total net emissions avoided through this project equates to 1,100,000 tons of CO2 per year. Successful execution of this project will provide a clear path forward for similar kinds of emissions reduction that can be replicated at other energy-intensive industrial facilities where the geology is suitable for sequestration. This project also represents a first opportunity for commercial development of geologic storage of CO2 in deep flood basalt formations. The Boise paper mill site is host to a Phase II pilot study being carried out under DOE’s Regional Carbon Partnership Program. Lessons learned from this pilot study and other separately funded projects studying CO2 sequestration in basalts will be heavily leveraged in developing a suitable site characterization program and system design for permanent sequestration of captured CO2. The areal extent, very large thickness, high permeability in portions of the flows, and presence of multiple very low permeability flow interior seals combine to produce a robust sequestration target. Moreover, basalt formations are quite reactive with water-rich supercritical CO2 and formation water that contains dissolved CO2 to generate carbonate minerals, providing for long-term assurance of permanent sequestration. Sub-basalt sediments also exist at the site providing alternative or supplemental storage capacity.

This paper describes a solvent regeneration method unique to CO2-binding organic liquids (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 can be exploited as a means to control CO2 loading. In this process, a chemically inert nonpolar “antisolvent” (AS) such as hexadecane (C16) is added to aid in de-complexing CO2 from a CO2-rich CO2BOL. The addition of this polarity assist reduces the temperature required for regeneration of our most recent CO2BOL, 1-((1,3-dimethylimidazolidin-2-ylidene)amino)propan-2-ol by as much as 73 °C. The lower regeneration temperatures realized with this polarity change allow reduced solvent attrition and thermal degradation. Furthermore, the polarity assist shows considerable promise for reducing the regeneration energy of CO2BOL solvents, and separation of the CO2BOL from the AS is as simple as a cooling the mixture to promote phase separation. Based on vapor–liquid and liquid–liquid equilibrium measurements of a candidate CO2BOL with CO2, with and without an AS, we present the evidence and impacts of a polarity change on a CO2BOL. Equilibrium thermodynamic models and analysis of the system were constructed using Aspen Plus®, and forecasts of preliminary process configurations and feasibility are also presented. Lastly, projections of solvent performance for removing CO2 from a subcritical coal-fired power plant (total net power and parasitic load) are presented with and without this polarity assist and compared to the U.S. Department of Energy's Case 10 monoethanolamine baseline.

The past practices of DOE and its predecessor agencies in burying radioactive and hazardous wastes have left DOE with the responsibility of remediating large volumes of buried wastes and contaminated soils. The Buried Waste Integrated Demonstration (BWID), has chosen to evaluate treatment of buried wastes at the Idaho National Engineering Laboratory (INEL). Because of the characteristics of the buried wastes, the potential for using high-temperature thermal treatment technologies is being evaluated. The soil-waste mixture at INEL, when melted or vitrified, produces a glass/ceramic referred to as iron-enriched basalt (IEB). One potential problem with producing the IEB material is the high melting temperature of the waste and soil (1,400-1,600{degrees}C). One technology that has demonstrated capabilities to process high melting point materials is the plasma arc heated furnace. A three-party program was initiated and the program involved testing an engineering-scale DC arc furnace to gain preliminary operational and waste processibility information. It also included the design, fabrication, and evaluation of a second-generation, pilot-scale graphite electrode DC arc furnace. Widely ranging simulants of INEL buried waste were prepared and processed in the Mark I furnace. The tests included melting of soils with metals, sludges, combustibles, and simulated drums. Very promising results in termsmore » of waste product quality, volume reduction, heating efficiency, and operational reliability and versatility were obtained. The results indicate that the graphite electrode DC arc technology would be very well suited for treating high melting point wastes such as those found at INEL. The graphite electrode DC arc furnace has been demonstrated to be very simple, yet effective, with excellent prospects for remote or semi-remote operation.« less