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    The solubility of water (H2O) in carbon dioxide (CO2) and nitrogen (N2) mixtures (xN2 = 0.050 and 0.100, mole fraction) has been investigated at 25 and 40 °C in the pressure range between 8 and 18 MPa. The motivation for this work is to aid the understanding of water solubility in complex CO2-based mixtures, which is required for the safety of anthropogenic CO2 transport via pipeline for carbon capture and storage (CCS) technology. The measurements have been performed using an FTIR spectroscopic approach and demonstrate that this method is a suitable technique to determine the concentration of water in both pure CO2 and CO2 + N2 mixtures. The presence of N2 lowers the mole concentration of water in CO2 by up to 42% for a given pressure in the studied conditions and this represents important data for the development of pipelines for CCS. This work also provides preliminary indications that the key parameters for the solubility of H2O in such CO2 + N2 mixtures are the temperature and the overall density of the fluid mixture and not solely the given pressure of the CCS mixture. This could have implications for understanding the parameters required to be monitored during the safer transportation of CO2 mixtures in CCS pipelines. The paper is available at http://www.sciencedirect.com/science/article/pii/S1750583615000444, DOI: 10.1016/j.ijggc.2015.02.002. UKCCSRC Grants UKCCSRC-C1-21 and UKCCSRC-C2-185.

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    This project will determine the dew point of water, or "water solubility", in impure CO2 mixtures (e.g. containing N2 and H2). At present, key data for defining water levels have not been determined. The data are important because liquid water is highly acidic in the presence of excess CO2; this acidity can be increased by trace amounts of SO2 and H2S and acidity will greatly accelerate corrosion. This research will provide the first accurate data for CO2 transportation systems, which can be used to develop accurate equations of state and define more robust pipeline specifications. These in turn can be applied to inform cost benefit analyses on the additional costs on the pipeline material and construction balanced against the cost of purification and the needs of safety. The research will provide critical physical property data to enable the safe and cost effective transportation of CO2. Grant number: UKCCSRC-C1-21.

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    The solubility of water (H2O) in carbon dioxide (CO2) and nitrogen (N2) mixtures (xN2 = 0.050 and 0.100, mole fraction) has been investigated at 25 and 40 degrees C in the pressure range between 8 and 18 MPa. The motivation for this work is to aid the understanding of water solubility in complex CO2-based mixtures, which is required for the safety of anthropogenic CO2 transport via pipeline for carbon capture and storage (CCS) technology. The measurements have been performed using an FTIR spectroscopic approach and demonstrate that this method is a suitable technique to determine the concentration of water in both pure CO2 and CO2 + N2 mixtures. The presence of N2 lowers the mole concentration of water in CO2 by up to 42% for a given pressure in the studied conditions and this represents important data for the development of pipelines for CCS. This work also provides preliminary indications that the key parameters for the solubility of H2O in such CO2 + N2 mixtures are the temperature and the overall density of the fluid mixture and not solely the given pressure of the CCS mixture. This could have implications for understanding the parameters required to be monitored during the safer transportation of CO2 mixtures in CCS pipelines. The paper is available at http://www.sciencedirect.com/science/article/pii/S1750583615000444, DOI: 10.1016/j.ijggc.2015.02.002. UKCCSRC Grants UKCCSRC-C1-21 and UKCCSRC-C2-185.

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    A new synthetic method for studying phase behaviour is described using Attenuated Total Reflection (ATR) spectroscopy. The method has been developed to provide relevant information on the solubility of water in CO2. The dew point of water has been determined at three different pressures, viz. (4.05, 5.05 and 6.03) MPa with mole fractions of water between 0.01 and 0.04. The data obtained fill the gap in the literature in these regions of pressures and temperatures and could be of high importance in the context of Carbon Capture and Storage (CCS) technology. Indeed, the presence of water in the captured CO2 could damage the pipeline used for CO2 transport. Hence, it is very important to have a fully understanding of the behaviour of the (CO2 + H2O) mixtures in wide range of temperature relevant for CCS. The paper is available at http://www.sciencedirect.com/science/article/pii/S0021961415003547, DOI: 10.1016/j.jct.2015.09.024. UKCCSRC Grant UKCCSRC-C2-185.

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    This poster on the UKCCSRC Call 2 project, Measurement of water solubility limits of CO2 mixtures to underpin the safe pipeline transportation of CO2, was presented at the Cranfield Biannual, 21.04.15. Grant number: UKCCSRC-C2-185.

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    This poster on the UKCCSRC Call 2 project Measurement of Water Solubility Limits of CO2 Mixtures to Underpin the Safe Pipeline Transportation of CO2 was presented at the CSLF Call project poster reception, London, 27.06.16. Grant number: UKCCSRC-C2-185. Monitoring the composition of mixtures which are of relevance to Carbon Capture and Storage pipelines is of high importance for the safe transportation of CO2 during the CCS process. Captured CO2 will contain varying amounts of impurities such as N2, H2, O2 and H2O. These are components which greatly affect the phase behaviour of the captured CO2. Being able to quantifiably monitor the composition and components of CCS-relevant mixtures is key for (i) safety; (ii) determining standard operating conditions. This project, incorporating several novel techniques, have been used to measure: • The phase behaviour and thermodynamic properties of CO2 containing varying amounts of impurities in order to improve or validate existing models of CCS relevant gas mixtures. • The solubility of water in impure CO2 CCS mixtures.

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    This presentation on the UKCCSRC Call 1 project, Determination of water Solubility in CO2 Mixtures, was presented at the Cranfield Biannual, 22.04.15. Grant number: UKCCSRC-C1-21.

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    This poster on the UKCCSRC Call 2 project, Measurement of water solubility limits of CO2 mixtures to underpin the safe pipeline transportation of CO2, was presented at the Cardiff Biannual, 10.09.14. Grant number: UKCCSRC-C2-185.

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    This project will tackle one of the key technical challenges facing the development of commercially viable CO2 transport networks: modelling the phase behaviour of impure carbon dioxide, under the conditions typically found in carbon capture from power stations, and in high-pressure (liquid phase) and low-pressure (gas phase) pipelines. Models for phase behaviour are known as equations of state (EoS). EoS vary in their mathematical form, accuracy, region of validity and computational complexity. Because different applications have different requirements, there is no single EoS that is ideal for all applications. This project will use cutting-edge computer algorithms to automatically reparameterise EoS for CCS modelling. This flexible technique will allow a user to specify their requirements and re-derive model parameters matched to their needs. Our algorithms will directly produce functional forms for EoS from experimental data, thus fully automating the derivation of EoS. This will enable users to rapidly produce bespoke EoS that are tailored to their particular application, and will enable these models to continually evolve as new measurements become available, ensuring that experimental advances are rapidly converted into improved CCS modelling and, ultimately, better performance and efficiency of real CCS processes. Grant number: UKCCSRC-C1-22.

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    Aqueous amine scrubbing was originally developed for natural gas treatment and is currently considered to be the current best available technology for post-combustion capture (PCC) of CO2 from both pulverised fuel (PF) and natural gas combined cycle (NGCC) power plants. A major issue is the severe thermo-oxidative degradation of alkanomaine solvents that occurs in PCC compared to natural gas processing, with the problem being compounded by the presence of acid gases that lead to the formation of heat stable salts (HSS). The accumulation of degradation products is known to reduce CO2 capture efficiency and cause excessive foaming and fouling and unacceptably high corrosion rates. Current measures to compensate for degradation involves purging spent solvent solution for reclaimation, makeup with fresh amine and the addition of anti-foam and oxidation/corrosion inhibitors. Reclaimer technologies based on distillation, ion-exchange and elecrodialysis have been developed to deal primarily with HSS where distillation has the advantage of removing both the HSS and their anions (i.e. formate and acetate). However, these technologies do not deal with the majority of the other degradation products, particularly those arising from thermal and oxidative degradation. Further, it has generally recognised that MEA forms high boiling polymeric material where N-(2-hydroxyethyl)-ethylenediamine (HEEDA), in particular, may continue to degrade in the presence of CO2 to form longer substituted ethlyenediamines. This proposal has been prompted by our extremely promising preliminary results that the thermal and oxidative degradation of an amine polymer (polyethyleneimine) can largely be reversed using both hydrogenation and hydrothermal (hydrous) treatments. We used non-catalytic hydropyrolysis and hydrous pyrolysis treatments at temperatures below 250oC which were clearly effective in reducing oxygen functionalities without causing any degradation of the polymer chain. The challenge is to partially reduce degraded amines to hydroxyamines and also, for polymeric forms, to induce some hydrogenolysis to reduce chain lengths. Hydrous pyrolysis has the potential advantage of not directly requiring hydrogen with water being the hydrogen source. Judicious choice of catalysts provides selectivity for hydrogenation and hydrogenolysis and research on amine degradation in natural gas sweetening has shown degradation products, such as N,N-bis(2-hydroxy-ethyl)piperazine and N,N,N-tris(2-hydroxyethyl)ethylenediamine, can be converted back to hydroxyamines by a hydrotreating reactions . •Directly targeting a high research priority identified by the RAPID Handbook, the proposed research aims to investigate novel reductive approaches for rejuvenating spent amine solutions from PCC plants, namely selective catalytic hydrotreatments at modest temperatures and H2 pressures and hydrous pyrolysis (hydrothermal conversion). The specific objectives are: 1.To apply the hydrogenation/ hydropyrolysis and hydrothermal treatments to individual compounds, including 1-(2-hydroxyethyl)-2-imidazolidone (HEIA), HEEDA, .N-(2-hydroxyethyl)acetamide and N-methylformamide 2.Based on the model compound results, to conduct experiments on actual fractions from degraded amine solvents, notably the residues from distillation containing HSS and the compounds targeted above; and 3.To use the results to define the overall benefits hydrogenation, hydropyrolysis and hydrothermal treatments in solvent rejuvenation and a basis for planning the subsequent research needed to take forward these new treatments, in terms of identifying how these treatments can best be conducted continuously. Grant number: UKCCSRC-C2-189.