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• Black liquor gasification was coupled with calcium looping. • Calcium looping for CO 2 capture and H 2 production was compared. • CO 2 capture route (39 €/t) was less expensive than H 2 production route (48.8 €/t). • CO 2 avoided cost was highly dependent on capital cost of black liquor gasification. • Export of H 2 had the lowest CO 2 avoided cost among black liquor gasification cases. Although considered one of the major energy-intensive industries (EIIs), the pulp and paper industry has also the potential for energy production from an industrial waste, black liquor. This study proposes black liquor gasification (BLG) coupled with calcium looping (CaL) as a CO 2 capture route for the pulp and paper industry. BLG with H 2 production (BLG-CaL-H 2), BLG with gas turbine combined cycle (BLG-CaL-GT) or with solid oxide fuel cell (BLG-CaL-SOFC) were considered. The dependence of carbon capture and storage (CCS) cost on the natural gas, limestone, electricity imported and H 2 sale prices aside the expenditures related with BLG-CaL were evaluated. The CCS route, based on CaL retrofitted to the pulp and paper plant, was found to have a lower cost of CO 2 avoided (39.0 €/tCO 2) when compared with BLG-CaL (48.8–57.1 €/tCO 2). Between the BLG-CaL scenarios, BLG-CaL-H 2 presented the lowest cost of CO 2 avoided (48.8 €/tCO 2) but the highest energy penalty. Based on the thermodynamic performance, it was shown that CaL retrofit and BLG-CaL-SOFC presented the best overall performance, turning the electricity importer reference plant into electricity exporter. The economic sensitivity showed that the capital requirement of BLG-CaL has a strong effect on the cost of CO 2 avoided for all alternatives. The H 2 production is also strongly affected by the H 2 sale price while BLG-CaL-SOFC and BLG-CaL-GT are strongly dependent on natural gas price. [ABSTRACT FROM AUTHOR]

Hydrogen Economy and Cyclic Economy are advocated, together with the use of perennial (solar, wind, hydro, geo-power, SWHG) and renewable (biomass) energy sources, for defossilizing anthropic activities and mitigating climate change. Each option has intrinsic limits that prevent a stand-alone success in reaching the target. Humans have recycled goods (metals, water, paper, and now plastics) to a different extent since very long time. Recycling carbon (which is already performed at the industrial level in the form of CO 2 utilization and with recycling paper and plastics) is a key point for the future. The conversion of CO 2 into chemicals and materials is carried out since the late 1800s (Solvay process) and is today performed at scale of 230 Mt/y. It is time to implement on a scale of several Gt/y the conversion of CO 2 into energy products, possibly mimicking Nature which does not use hydrogen. In the short term, a few conditions must be met to make operative on a large scale the production of fuels from recycled-C, namely the availability of low-cost: i. abundant, pure concentrated streams of CO 2 , ii. non-fossil primary energy sources, and iii. non-fossil-hydrogen. The large-scale production of hydrogen by Methane Steam Reforming with CO 2 capture (Blue-H 2) seems to be a realistic and sustainable solution. Green-H 2 could in principle be produced on a large scale through the electrolysis of water powered by perennial primary sources, but hurdles such as the availability of materials for the construction of long-living, robust electrochemical cells (membranes, electrodes) must be abated for a substantial scale-up with respect to existing capacity. The actual political situation makes difficult to rely on external supplies. Supposed that cheap hydrogen will be available, its direct use in energy production can be confronted with the indirect use that implies the hydrogenation of CO 2 into fuels (E-fuels), an almost ready technology. The two strategies have both pros and cons and can be integrated. E-Fuels can also represent an option for storing the energy of intermittent sources. In the medium-long term, the direct co-processing of CO 2 and water via co-electrolysis may avoid the production/transport/ use of hydrogen. In the long term, coprocessing of CO 2 and H 2 O to fuels via photochemical or photoelectrochemical processes can become a strategic technology. • Hydrogen Economy and Cyclic Economy are discussed as an option for defossilizing anthropic activities and mitigating climate change. • In the short term, a few conditions must be met to make operative on a large scale the production of fuels from recycled-C. • In the medium-long term, the direct co-processing of CO 2 and water via co-electrolysis may avoid the production/transport/ use of hydrogen. • In the long term, coprocessing of CO 2 and H 2 O to fuels via photochemical or photoelectrochemical processes can become a strategic technology. [ABSTRACT FROM AUTHOR]

Post-combustion capture (PCC) of CO 2 from fossil fuel-fired power station flue gas is one of many technologies that are being developed to reduce anthropogenic greenhouse gas emissions in the medium term. Wet-gas scrubbing using aqueous amines is currently the most mature PCC technology suitable for separating CO 2 from coal-fired power station flue gases. In this study, a series of twelve samples of a degraded 30% (w/w) MEA absorbent were obtained over a six month pilot scale PCC campaign at a brown coal-fired power station in Australia. These samples were used to investigate the accumulation of heat-stable salts, inorganics and minerals. The heat-stable salts concentration increased from 0.80 to 2.29% (w/w, as MEA) and organic acids from the oxidative degradation of MEA were the largest component of heat-stable salts. Acid gases such as SO x and NO x , make-up water, ultra-fine fly-ash and corrosion were all sources of the minerals and inorganics that accumulated in the aqueous MEA absorbent. Corrosion was the single biggest contributor of transition metals and the abrupt change in ratios of Fe, Cr and Mo suggests that the dominant corrosion mechanism may have changed towards the end of the campaign. The rapid accumulation of minerals and inorganics during this PCC campaign highlights the importance of continuing research into the interactions between amine absorbents and inorganic or mineral contaminants. The data presented in this study are an important resource for design of laboratory scale experiments to investigate these physical and chemical interactions between aqueous amines, minerals and inorganics. [ABSTRACT FROM AUTHOR]

According to the construction of the cascade hydropower stations in the lower reaches of the Yalong River and the ecological environment condition of the river, a medium and long-term optimal dispatching model with the goal of maximizing the power generation benefits of the cascade hydropower stations is established, and the dynamic programming method is used to optimize the solution, so as to obtain the ten-day average maximum power generation of cascade hydropower stations. According to the latest relevant research at home and abroad, it is found that during the power generation process of the hydropower station, the discharge will produce certain greenhouse gas (GHG) emissions during the delivery process. In this paper, the greenhouse gas emissions existing in the power generation process of cascade reservoirs are considered, and the typical values are selected to calculate the average greenhouse gas (mainly CO 2) emissions from 2001 to 2018, twelve plants with strong carbon sequestration and oxygen release capacity and suitable for growing in the basin are selected, and the mitigation and improvement measures of greenhouse gas emissions around the reservoirs in the basin are given. A new research idea is provided for the Yalong River cascade reservoirs to focus on the power generation benefits while reducing the greenhouse gas emission situation to a certain extent. [ABSTRACT FROM AUTHOR]

• Step-by-step procedure to develop the tabulation and map component of UIC class VI permit. • Qualitative risk assessment methodology for all types of wells within AoR penetrating the confining zones. • Highlights the need for crossflow modelling of CO 2 leakage through improperly plugged wells. • Generalized categorization of legacy wells based on geologic penetrations and protections. Carbon Capture & Storage (CCS) refers to capturing the anthropogenic carbon dioxide (CO 2) at a source followed by injecting and storing it safely in the subsurface. The success of the CCS projects therefore heavily relies on how efficiently the confining zones (containment seals) prevent migration of the CO 2 to the surface and/or to the underground sources of drinking water (USDW) through leakage pathways. CCS projects requires drilling of Underground Injection Control (UIC) Class VI wells for permanent storage of CO 2 in subsurface. Detailed information of all the wells within the Area of Review (AoR) is needed to develop the map and tabulation components of the Class VI well permit application. This paper discusses the generic process that can be used by permit applicants to develop the dataset necessary for preparing the map and tabulation components of the Class VI permit application and perform qualitative risk assessment of all the wells within the AoR. This methodology directs the corrective action plans as well as monitoring plans to some extent. Results of the application of the newly developed methodology for wells in Illinois basin is discussed in detail. This methodology can be applied to all wells including orphaned wells, abandoned wells, active oil and gas wells, stratigraphic wells, disposal wells, etc. This methodology generalized categorization of legacy wells that will help in easier comparison of different CCS projects across the globe. The qualitative risk assessment methodology discussed in this paper is a good starting point for developing crossflow modeling. [ABSTRACT FROM AUTHOR]

• A new method for quantitatively monitoring CO 2 saturation in depleted gas reservoirs is proposed. • The ratio of the near detector's neutron capture gamma-ray count rate to the far detector's thermal neutron count rate measured by a four-detector pulsed neutron logging tool can effectively differentiate between CO 2 and CH 4. • The new method has higher CO 2 sensitivity compared to conventional count ratio methods. With favorable trap conditions and comprehensive infrastructure, depleted gas reservoirs create ideal spaces for the economic and efficient storage of carbon dioxide (CO 2). Accurate monitoring of CO 2 saturation is important for understanding CO 2 storage efficiency and distribution status. This paper proposes a new method for the quantitative monitoring of CO 2 saturation in CO 2 sequestration projects within depleted gas reservoirs. The new method uses the ratio of the near detector's neutron capture gamma-ray count rate to the far detector's thermal neutron count rate (RCN) measured by a four-detector pulsed neutron logging tool. In this paper, the RCN responses for different CO 2 saturation levels are studied using the Monte Carlo method, and the methods for roughly and accurately calculating CO 2 saturation are given. Moreover, the effects of formation factors such as lithology, clay mineral content, bound water salinity, and borehole environment on the RCN response are studied. Finally, the applicability of the RCN method is verified through a simulation example. The results show that the RCN method not only has high CO 2 sensitivity, but it also can accurately determine CO 2 saturation in depleted gas reservoirs and control the error of CO 2 saturation calculation within 2%. This study offers robust technical support for the evaluation of CO 2 saturation in depleted gas reservoirs. In addition, the proposed method has been proved applicable in the evaluation of CO 2 saturation in low-porosity reservoirs. [ABSTRACT FROM AUTHOR]

• CCUS development among EU countries with the latest progress in the field. • Realization of EGD targets with CCUS technology in EU. • Applicability of benchmarking method to compare environmental profiles. • UK and the Netherlands are among top countries with rapid CCUS development. • Poland and Germany with a high level of difficulty in achieving the EGD targets. Carbon Capture Utilization and Storage (CCUS) is a technology highlighted as one of the tools in climate change mitigation and one of the ways to reach the goal of 1.5℃ set by the Paris Agreement. The European Commission (EC) developed this goal by creating and implementing the European Green Deal (EGD) – the European Union's (EU) environmental policy. This paper provides an analysis of environmental policies and an overview of crucial CCUS projects of selected member states based on a benchmarking analysis of 27+ UK member states. An overall review of a total of 28 countries was undertaken based on economic and environmental factors. Afterward, a benchmarking analysis was performed ranking the countries according to the TOP10 for the selected five categories: total net emissions with international transport, percentage share of the energy sector, percentage share of fossil fuels, percentage share of fossil fuels in the Gross Electricity Production (GEP), and numbers of CCUS projects. Subsequently, a detailed and comprehensive overview of four selected member states was done, with a special focus on the national energy policy towards net-zero emission goals, the role of CCUS in domestic environmental policy, with current projects and facilities development. Finally, this paper outlines how the EGD has reformed the national energy policies of selected member states, and what is the part of CCUS technology in the national efforts towards climate neutrality. [ABSTRACT FROM AUTHOR]

CO 2 fixation from seawater is an effective way to mitigate climate change and has gained widespread attention in recent years. However, the existing research mostly involves stoichiometric bases and bipolar membrane electrodialysis methods, and the performance of direct seawater electrolysis for CO 2 fixation is presented with limited studies and rare research data. The performance evaluation on CO 2 fixation based on the technology of direct seawater electrolysis is presented in this paper. Energy consumption, decalcification rate, and calcium carbonate production rate are employed as performance indexes to assess the feasibility of CO 2 fixation through direct electrolysis of seawater. The simulation method is adopted in this paper, with validation based on data from experiment. As a result, the minimum energy consumption for per amount of calcium carbonate deposited ranges from 557.82 to 730.06 kJ/mol CaCO 3 at the seawater flow rate range of 0.01–0.1 L/s, which has an advantage over other electrochemical CO 2 capture method. Additionally, the decalcification rate and calcium carbonate production rate can reach a maximum of 100% and 0.36 mmol/s respectively. The conclusions presented in this paper can serve as a valuable guide for conducting large-scale evaluations or application analyses. [Display omitted] • A novel method for CO 2 fixation and seawater decalcification is proposed. • Direct electrolysis of seawater is applied as a substitute for chemical reagent. • The model of electrolyzer is established and its reliability is validated. • Performance parameters of the proposed method is analyzed. • The energy consumption range is 557.82–730.06 kJ/mol CaCO 3. [ABSTRACT FROM AUTHOR]

The long-term safety and integrity of CO 2 storage in geological formations requires understanding of the interactions along the injection well between CO 2 and casing, cement, and rock, which may lead to potential leakage pathways and compromise the storage security. The current knowledge on the large scale evaluation of casing-cement or cement-rock composites behavior under reservoir pressure and temperature (P&T) conditions and CO 2 flow is still limited as the related experiments are challenging. Furthermore, intermittent cold CO 2 injection or cooling resulting from the Joule-Thomson (J-T) effect during injection in depleted hydrocarbon reservoirs may lead to freeze-thaw cycling in the near wellbore area. Such processes have barely been investigated to date, as they are also technically demanding. In this paper, the above challenges have been addressed by constructing a test facility that includes a large scale reactor with a length of 2 m, a diameter of 0.7 m and operating pressure up to 20 MPa. The facility has been used to experimentally investigate the behavior of the casing-cement composite under P&T cycles at CO 2 flow conditions. Furthermore, cement, caprock (e.g. shale), and cement-caprock composite tightness to CO 2 flow was investigated on a small scale setup similar to the large scale one. The results show that cement class G, caprock (shale), and cement-caprock composite remain tight. The effect of pressure cycling on casing-cement bond showed that the composite exhibits enough low permeability at ambient temperature using CO 2. The effective pressure is a critical factor; the higher the effective pressure, the lower the permeability. Temperature cycling effect on the composite casing-cement was also investigated and the results showed that at subzero temperatures freezing of water in the pore space of cement caused no hydraulic conductivity (no flow of CO 2), moreover, no significant change in the original permeability was observed after thawing. • Large scale experimental setup is built for studying wellbore integrity. • Transient two-chamber method is used for permeability measurements. • Permeability results proved tightness of cement class G, caprock, and cement-caprock. • Subzero temperature has no effect on permeability of casing-cement composite. • Pressure cycling on casing-cement shows significant effect on the tightness. [ABSTRACT FROM AUTHOR]

Policies that incentivize the capture and geological storage of CO 2 from large point sources ('CCS'; and more recently, atmospheric removals), have so far tended to reward the resultant avoided CO 2 emissions (or CO 2 removals) achieved by operators at the point of capture. The expectation has been that geological CO 2 storage sites, as well as the connecting infrastructure, will be developed and operated based upon the funding delivered from the single point of incentive (e.g. under an emissions trading system or a carbon tax, only CO 2 capture installation operators are absolved of the obligation to acquire and surrender CO 2 emission rights or to pay the tax). Project-based crediting mechanisms (e.g. in the voluntary carbon market) tend to treat the entire chain of operations as a single entity to be supplied with emission reduction or removal credits. Consequently, there has been minimal explicit financial incentive to store CO 2. Yet a multiple gigaton-per-year scale capture and storage industry requires complex CO 2 networks to evolve, with multiple sources connecting to multiple sinks, with installations owned by different operators with different technical expertise, climate mitigation goals and obligations. This multiplicity of goals and incentives can create agency problems and cross-chain risks, which impact negatively upon investment decisions. In this paper, we review the history, evolution and potential of geological net zero (GNZ) and carbon storage (or takeback) obligation concepts applied to fossil carbon producers and suppliers as a means to address these risks alongside policies aimed at atmospheric net zero (ANZ) and fossil carbon emitters. [ABSTRACT FROM AUTHOR]

• Introduction, explain the development in CCS industry (fast groing challenge of hub project mixing different sources of CO2, causing effects of impurities from different sources cause impact on integrity and interact to cause even more issues. • Impurities (H2O, SO2, H2S, O2 and NO2) chemical interactions and their limits, testing background, solubility limits and model. • Results, identified limits from testing and medelling. • Review oif results and put them in perspective, when and how do impurtities react and what are the identified limits and potential results of acid drop out. • Explaining the corrosion mechanism bridging the results toward practical applications and potential consequences (corrosion rates). • Corrosion control options. • Summary and guidance, including identified safe limits, testing and modelling, corrosion management and gaps and way forward. Carbon Capture and Storage (CCS) involves capturing, treating, transporting and storage of CO 2 to ensure long-term isolation from the atmosphere. In recent years there has been a significant increase in CCS project proposed and initiated. A number of these proposed projects aim to capture CO 2 from multiple industrial emitters (sources) to reduce the carbon footprint for these emitters. Depending on the CO 2 composition and operating conditions, separate phases may be formed. It has been identified that these separate phases can comprise of water or reaction products including strong acids, or sulphur that can cause severe corrosion. To ensure long term integrity of the facilities, a safe project CO 2 specification needs to be identified. Tight control of CO 2 stream composition and operating conditions together with the selection of suitable materials are essential to ensure the integrity for all operating scenarios including upsets. This paper focuses on identification of impurity limits for a CCS project, which are captured in a project's CO 2 specification. Special attention is given to one specific group of impurities that can react and cause drop-out of a highly corrosive phase. Sound understanding of the mechanisms that stand behind these chemical reactions, thermodynamics, the role of phase behaviour and potential consequences are needed to be able to identify or/and adjust impurity limits for a CO 2 specification in projects. This work aims to improve understanding provide guidance and to reveal knowledge gaps that require addressing in order to identify a safe CO 2 specification for a CCS project. [ABSTRACT FROM AUTHOR]

• New carbon-sequestration geosystem paradigm proposed for screening CO 2 repositories. • Deposition, burial history 1st-order controls on repository attributes, traps, etc. • Genetic understanding of geology enables property prediction away from data control. • Case-study application to heavily industrialized region of onshore Canada. In this paper, I propose a new geoscience paradigm for evaluating potential carbon-sequestration targets. I introduce the term carbon-sequestration geosystem to study and describe portions of sedimentary basins where all the geologic components necessary for the safe and long-term storage of CO 2 are present. The purpose of this type of analysis, most appropriately applied at a basin-screening stage, is to derive a holistic, genetic, and predictive understanding of the geology – the depositional systems, structural setting and other factors that are direct controls on storage, injectivity, potential for induced seismicity, and other critical factors. To illustrate the concepts, I present a re-evaluation of the geologic carbon-sequestration options in Southern Ontario (Canada) where business and environmental needs, mostly associated with hard-to-abate industries, require urgent action. Legacy wireline-logs, core, and outcrop data are the main data sources available in this onshore setting. The results of this new, independent study are broadly similar to those of previous studies: the Cambrian section, a saline aquifer, is the most likely candidate to be a CO 2 repository. However, the methodology used identified several issues (e.g., stratigraphic heterogeneity, proximity to basement) that will need addressing by targeted data collection and/or analysis before site-selection for a test should be undertaken. [ABSTRACT FROM AUTHOR]

• It maps the CO 2 storage potentials in shale basins in China comprehensively. • Both shale oil and gas basins are quantitatively estimated via different equations. • Basins are classified into three tiers for carbon storage with varied time scales. • The equations for the estimations of CO 2 storage potentials are optimised. • The density variation of CO 2 at different conditions was considered. China is the second largest shale gas and oil producing country possessing large and significant shale basins, and it is also one of the top carbon emitting countries. Therefore, there is significant potential to store CO 2 in shales in China to remove the carbon emission and enhance and gas recovery simultaneously. This research provides a comprehensive prediction of potentials of CO 2 storage in major shale gas/oil basins in China based on most recent publications where density variation of CO 2 at different subsurface conditions is considered and the different stages of development are classified. We optimise the calculation equations for shale gas and oil respectively, and further classified the three tiers (i.e. commercial, potential and possible reservoirs) in the calculation to prioritise the sequestration site selection. A total of around 6194 Gt, CO 2 sequestration in shales, including 172 Gt for commercial, 849 Gt for potential and 5147 Gt for possible storage, equivalent to a total of 620 years' carbon emissions in China is expected. These can be realised in around 20 years, 20–50 years and 50–100 years respectively. For future applications, more concerns should be on the evaluation criteria of sequestration sites in shales, CO 2 fracturing mechanisms and potential leakage, multi-phase seepage and reactions, and environmental monitoring systems. As a comprehensive assessment of potentials of CO 2 storage in shale basins in China, this paper will provide an important guide for future academic studies, industrial operations and government policy making. [ABSTRACT FROM AUTHOR]

• Experiment at upper-temperature limit for CO 2 sequestration in basalt. • CO 2 sequestration experiment in metasedimentary rocks. • PHREEQC modeling compared to experimental results. • Numerical models might overestimate CO 2 sequestration at high temperatures. The potential for in-situ CO 2 sequestration was analyzed experimentally for one basaltic hyaloclastite sample from the Nesjavellir geothermal reservoir in Iceland and three metasedimentary rock samples from the Kızıldere geothermal field in Turkey. Based on batch reaction experiments, this paper demonstrates the interaction between a CO 2 gas-charged fluid and rock samples from these reservoirs. The experiments were conducted at 260 °C and 0.8 MPa, and 105 °C and 17 MPa for the basaltic and metasedimentary rocks, respectively. The experimental results indicate that CO 2 sequestration within the glassy basaltic rocks is hampered by zeolite, chlorite, and anhydrite, which compete with carbonate minerals to uptake divalent cations at the P-T conditions applied. In contrast, the carbonation process for the metasedimentary rocks is inhibited by their mineralogical composition. Generally, these rocks are less reactive and provide an insufficient supply of divalent cations. The batch reactor experiments were numerically simulated with the PHREEQC geochemical modeling program. The simulations indicate that CO 2 sequestration is feasible at the tested P-T conditions, provided that silicate and SO 4 mineralization is suppressed for the basaltic rocks and that there is an effective source of divalent cations for the metasedimentary rocks. [ABSTRACT FROM AUTHOR]

This paper reports the preparation and characterization of asymmetric membranes for direct air capture (DAC) in polysulfone membrane contactors. In the previous studies it was found that blending the polysulfone with modified Lupasol G20 improved the polysulfone membrane performance; however, the hydrophobicity and stability of the additive require improvement for the application in gas/liquid system. In order to achieve this objective, in the current study, Lupasol G20 was grafted with phenyl isocyanate via urea linkages in a solvent-free and eco-friendly method. Membranes with different amount of the additive were prepared by phase inversion and characterized by several techniques in terms of morphology, porosity, wettability, and stability in aqueous KOH solution. Finally, CO 2 solubility and mass transfer coefficient were determined and correlated with membranes' performance in the direct air capture device. In general, it was found that the presence of the additive greatly improved the characteristics of the membranes in terms of CO 2 capture efficiency and robustness, outperforming the results obtained previously. The best results for were obtained with 5% additive content reaching 0.18 [mol/m2s]. [Display omitted] • Modified Hyperbranched Polyethyleneimine (UG20) was synthesized by grafting Lupasol G20 with phenyl isocyanate groups. • Polysulfone (PSF)/UG20 asymmetric blended membranes with different UG20 content, for CO 2 capture, were prepared by phase inversion. • CO 2 solubility, permeability and absorption values were improved in PSf/UG20 blended membranes. • CO 2 assimilation rate of blended membranes was higher than in natural stomata and in PSF-based modules previously reported. • PSf/UG20 5% displayed the highest CO 2 assimilation rate. [ABSTRACT FROM AUTHOR]

• • Three approaches are compared for dynamic simulations of CO 2 capture. • • The influence of key operating factors of CHP plants on approaches is studied. • • The influence of time step on the amount of captured CO 2 is studied for each approach. • • Recommendations are given for the selection of approaches. Integrating CO 2 capture with biomass/waste fired combined heat and power (CHP) plants is a promising method to achieve negative emissions. However, the use of versatile biomass/waste and the dynamic operation of CHP plants result in bigger fluctuations in the properties of flue gas (FG), e.g. CO 2 concentration (CO 2 vol%) and flowrates, and the heat that can be used for CO 2 capture, when comparing with coal fired power plants. To address such a challenge, dynamic modelling is essential to accurately estimate the amount of captured CO 2 and optimize the operation of CO 2 capture. This paper compares three dynamic approaches commonly used in literature, namely using the ideal static model (IST) and using dynamic models without control (Dw/oC) and with control (DwC), for MEA based chemical absorption CO 2 capture. The performance of approaches is assessed under the variations of key factors, including the flowrate and CO 2 vol% of FG, and the available heat for CO 2 capture. Simulation results show clear differences. For example, when the CO 2 vol% drops from 15.7 % to 9.7 % (about 38 %) within 4 hours, DwC gives the highest amount of captured CO 2 , which is 7.3 % and 22.3 % higher than IST and Dw/oC, respectively. It is also found that the time step size has a clear impact on the CO 2 capture amount, especially for DwC. Based on the results, suggestions are also provided regarding the selection of dynamic modelling approaches for different purposes of simulations. [ABSTRACT FROM AUTHOR]

Injection of CO 2 foam into saline aquifers is a practical method to store CO 2 ; however, generating stable CO 2 foam at high temperatures and salinities remains a challenging task. Therefore, this research fully explains the effect of formation water components (NaCl, CaCl 2 , MgCl 2 , Na 2 SO 4 , and NaHCO 3) on the stability of generated foam under harsh conditions. In this regard, a high-temperature and high-pressure (HPHT) foam analyzer was used to investigate the foamability and stability of CO 2 foam at 100 °C and 1000 psi. The liquid phase contained 0.5 wt% of Armovis surfactant dissolved into 0.1, 0.5, and 1M concentrations of formation water ions. Moreover, the dynamic surface tension of the selected surfactant solutions was investigated using an optical tensiometer. For the first time, this paper investigates the behavior of foam during the foaming process. During the injection of CO 2 , the average bubble count for the low salt concentration increased sharply and then dropped until it plateaued. However, the average bubble count for the higher salt concentration gradually increased until the foaming process stopped. These phenomena occurred because of the kinetic adsorption rate of the surfactant micelles at the interface. Additionally, we studied the effect of salt concentrations on bubble count half-life, bubble coarsening, and foam volume decay during the static condition. We observed that the increase in salt concentration resulted in more stable foam due to the reduction of CO 2 solubility in water. The foam half-life for 0.1 M of NaCl was 190 min, while it was more than 250 min for 1M of NaCl. A similar trend was observed for CaCl 2 and MgCl 2. The results of the HPHT foam analyzer concluded that the higher concentration of salt ions presented a more stable foam. Also, the use of Armovis surfactant is promising for the stabilization of CO 2 foam at high temperatures and salinities. • Individual formation water ions impact on CO 2 foamability and foam stability was investigated at high temperature. • The behavior of CO 2 foam during the injection of CO 2 was investigated using HPHT foam analyzer. • Faster foam generation is observed in the presence of low salinity salts. • Ultra-stable CO 2 foam was achieved using Armovis (viscoelastic surfactants) at high salinity salts. [ABSTRACT FROM AUTHOR]

CO 2 capture by aqueous primary and secondary alkanolamine solutions is a recognized technology in industrial CO 2 separation processes. Yet, certain obstacles caused by high-energy consumption due to the amine regeneration demands, and the formation of thermally stable salts require to be overcome for the development of these solvents. In this paper, glycerol, as a beneficial by-product of biodiesel production, has been introduced as a second promising CO 2 absorbent for aqueous diethanolamine solution in a Y-type micro-reactor with dimensions of 800 µm × 4 cm × 19 cm. The experiments of CO 2 capture into the hybrid blend of DEA-Glycerol were investigated at ambient pressure and the operating temperature of 25–45 °C, volumetric gas flow rate of 100–300 ml/min, DEA concentrations of 1.5–2.5 M, and glycerol concentrations of 5–15%wt. Experimental results demonstrated that adding 10 wt% glycerol in the aqueous blend of 2.5 M DEA-Glycerol boosts the CO 2 removal percentage, RP, up to 96.89%, and enhances the volumetric overall gas-phase mass transfer coefficient, K G a V , and volumetric mass transfer flux, N A a V , to 34.89 kmol/m3.h.kPa and 88.04 kmol/h.m3, respectively. Furthermore, based on the Box-Behnken statistical responses, under the constant concentration of 2 M of DEA, increasing the presence of glycerol from 5 to 10 wt% in the hybrid blend of DEA-Gly can intensify the CO 2 RP, K G a V , and N A a V values by 2.12% and 8.66%, and 1.80%, respectively, illustrating the glycerol contribution on the CO 2 capture process. • DEA-glycerol hybrid solvent was investigated for CO 2 capture in a Y-type micro-reactor. • Glycerol contribution on CO 2 RP and K G a V varies from 83.19% to 90.27% and from 38.19 to 48.74 kmol/m3.h.kPa, respectively. • The effect of absorption temperature on CO 2 mass transfer performance is negligible. • Adding glycerol to the hybrid solvent increases the values N A a V up to 226.3. kmol/m3.h. [ABSTRACT FROM AUTHOR]

The utilization of clathrate hydrates as a highly promising technology for CO 2 capture and separation is the focus of this review paper. We present an in-depth exploration of hydrate-based CO 2 capture technology, highlighting the use of various additives to enhance the performance of CO 2 hydrate formation, as well as the separation and capture of CO 2 from gas mixtures containing N 2 /H 2 /CH 4. By employing thermodynamic promoters, CO 2 molecules can efficiently occupy hydrate cages under moderate temperature and pressure conditions, while kinetic promoters improve the kinetic properties of hydrate formation. Key performance indicators such as (normalized) gas uptake, t 90 , and separation factor are comprehensively discussed and summarized. Moreover, this review introduces additional applications of CO 2 hydrates, such as their potential in cold energy storage due to their high heat of formation (∆ H d) of approximately 500 kJ/kg, surpassing that of ice at 333 kJ/kg. Additionally, we explore the advantages of the CH 4 -CO 2 replacement method, which offers an energy production alternative without the drawbacks of sediment subsidence and ecosystem destruction. Through a comprehensive review, we emphasize the potential of clathrate hydrates as a promising technology for CO 2 capture and underscore the importance of further research in this area. Ultimately, CO 2 hydrates represent a future direction for mitigating global warming. [Display omitted] • Various thermodynamic and kinetic hydrate promoters were explored. • Gas separation performances of hydrate-based technologies were summarized. • Potential of cold energy storage material with high dissociation enthalpy was addressed. • Various studies of CH 4 -CO 2 replacement were introduced. [ABSTRACT FROM AUTHOR]

Biomass Waste Derived Porous Carbon (BWDPC) is widely used for its ability to adsorb carbon dioxide (CO 2) in large-scale industrial operations, making it a leading solution for combating air pollution and climate change issues. However, factors such as temperature, pressure, and surface area can influence its performance in adsorbingcarbon dioxide. To maximize CO 2 adsorption, it is vital to determine the relationships among these variables. In this paper, we use several preprocessing techniques and various machine learning algorithms, such as Gradient Boosting Regressor, Convolutional Neural Networks, Multi-Layer Perceptron, and Long Short-Term Memory, to explore the efficacy of these algorithms in predicting CO 2 capture capacities. We augment our datasets by generating new features and in turn our ML models achieve a better performance on the augmented datasets compared to the original dataset. Our models achieved r 2 score of 90.7 % on the training set and 85.73 % on the test set of the augmented datasets. Furthermore, we were able to determine that the ratio of carbon to pressure as well as temperature, and aspects tied to the physical conditions of the adsorbent material emerge as the most influential factors in CO 2 adsorption. A python implementation of all our experiments is publicly available in Github https://github.com/mmaheri/CO2_Capturing.git. • We apply various preprocessing steps and augment the original dataset by generating new features. • We compare the performance of various machine learning algorithms on the original and augmented datasets. • The machine learning algorithms show a better performance on the augmented dataset in terms of r2 score. • Convolutional Neural Network and Gradient Boosting Regression exhibit the best performance. • The ratio of carbon to pressure as well as temperature, and aspects tied to the physical conditions of the adsorbent material emerge as the most influential factors in CO2 adsorption. [ABSTRACT FROM AUTHOR]

• CCS injection well metallurgy and corrosion. • Impurities in the CO 2 are most important. • The chloride content and temperature of the reservoir must be considered. Carbon capture and sequestration (CCS) and carbon capture utilization and storage (CCUS) projects continue to develop as an effective method to reduce anthropogenic CO 2 emissions. Injection wells for these projects are often required to retain integrity over long operational lives, sometimes 50 years or longer. When it is determined from process conditions that free water may or will be present, either condensing from the CO 2 injectate itself or due to injection into a water-bearing formation, the need for a corrosion resistant alloy (CRA) is required to ensure sufficiently long service life. For well designers and operators, there is a growing need for comprehensive guidelines for the selection of suitable corrosion resistant alloys (CRAs). This paper summarizes important parameters developed through the Plains CO 2 Reduction (PCOR) Partnership that need to be considered for general materials selection for use within CO 2 injection wells based on available data. [ABSTRACT FROM AUTHOR]

• Design study of a 10,000 tons/a CO 2 power-to-lower olefin plant in a cement factory. • Comparison of lower olefin production via FT syncrude and methanol as intermediates. • Technical evaluation of the defined process routes via process-related KPIs. • Calculation of the net production cost of lower olefins. This paper describes the simulation and techno-economic evaluation of a carbon dioxide capture and utilization unit integrated in a cement plant with a capacity of 10,000 tons of CO 2 per year. The aim is to utilize CO 2 along with hydrogen to produce lower olefins (C 2 –C 4), the feedstock for polyolefin production. In a first step, three process routes, namely a Fischer–Tropsch synthesis with steam cracker, a methanol synthesis with rWGS syngas production and a methanol synthesis with direct hydrogenation of CO 2 , latter two followed by a methanol-to-propylene unit, are simulated in ASPEN Plus V12.1®. Furthermore, the effect of a high- and a low-temperature electrolysis on key performance indicators are also considered in the evaluation. Additionally, an estimation of investment, operating and specific net production costs (NPC PR) of the different process routes is made. The evaluation is based on the comparison of calculated global efficiencies, specific energy consumption (SEC), NPC Pr and yields of the lower olefine products (C 2 –C 4). The power-to-lower olefin plant, consisting of an amine scrubber unit, a PEM electrolysis and a Fischer–Tropsch synthesis with downstream steam cracker proves to be the most efficient process route for polyolefin production, resulting in a global efficiency of 38.2 %, an SEC of 34.4 kWh/kg and an NPC Pr of 14.92 EUR/kg of lower olefine product. [ABSTRACT FROM AUTHOR]

Ca-Looping technology has experienced a substantial development in the technical readiness level in the last years, especially in its application as post-combustion CO 2 capture technology in power plants. Experimental results from MW-scale power plants worldwide have confirmed post-combustion Ca-Looping process using interconnected circulating fluidised bed reactors as a promising technology for CO 2 capture. Among the different fields of research having contributed to this breakthrough, modelling activity aiming at assessing sorbent properties, interpreting results from experimental reactors or assessing technology scale-up through large-scale reactors and process integration have played a crucial role. This paper aims at reviewing and discussing findings obtained by different research groups worldwide about post-combustion Ca-Looping process modelling. Assumptions made with respect to sorbent performance, reactor operating conditions and process integration between different components are crucial when evaluating the performance of the Ca-Looping process as a post-combustion technology for CO 2 capture. With the aim of understanding the importance of these assumptions, this paper covers particle reaction and reactor models for carbonation and calcination steps, assessing the impact of the conditions used for their determination into their reactivity predictions, as well as process modelling works that assess performance obtained when integrating a Ca-Looping process into a power plant. Indications on the research needs detected among the reviewed works have also been highlighted in this work to contribute to the advancement of the knowledge on the Ca-Looping technology. [ABSTRACT FROM AUTHOR]

• The dissolved inorganic carbon can indicate the migration of supercritical carbon dioxide. • The dissolution pattern of chlorite is related to the content of dissolved inorganic carbon. • The contour maps of carbon dioxide are proposed to quantitatively evaluate its migration. • Three-stage of the evolution of calcium represent the three types of carbon sequestration minerals. A monitoring method that uses the variation in water chemical characteristics of the deep storage layer was studied by a three-dimensional numerical model under the background of a CO 2 -enhanced water recovery (CO 2 -EWR) site in the Junggar Basin. The effect of water chemical characteristics on the migration of CO 2 in different phases and the transformations of major sequestered carbon minerals were determined from the resulting mechanism. The results show that the evolution of water chemical characteristics, such as pH, Ca2+ and dissolved inorganic carbon (DIC), can effectively indicate the migration distance and time of dissolved CO 2 and supercritical CO 2. The times corresponding to the turning points of the pH and DIC change curves at the monitoring points can plot the isochronal maps of dissolved and supercritical CO 2 migration, which can be used to quantitatively evaluate CO 2 migration in the reservoir. The changes of DIC and Ca2+ can be used to infer the main carbon sequestration minerals: at the rapidly falling stage of Ca2+ concentrate over time and the low concentrate of DIC, the main carbon sequestration mineral is calcite, and in other conditions is ankerite. Water chemical characteristics can identify the extent of injected CO 2 impact in the corresponding region. This paper provides an alternative method for monitoring CO 2 migration and conversion in different phases and determining the extent of injected CO 2 impact in a region by the type of sequestered carbon minerals. [ABSTRACT FROM AUTHOR]

The growing concerns over global warming and carbon dioxide emissions have driven extensive research into novel ways of capturing carbon dioxide in power generation plants. In this regard, oxy-fuel combustion has been considered as a promising technology. One unconventional fuel that is considered is sour gas, which is a mixture of methane, hydrogen sulfide and carbon dioxide. In this paper, carbon dioxide is used as the dilution medium in the combustor and different combined cycle configurations were considered and analyzed, each with a different way of dealing with the harmful sulfur products in the working fluid. Out of these options, which included acid resistance, no-condensation and SO x removal cycles, it is found that the cycle using acid resistant materials to have the best efficiency at 45.2%. However the cost of electricity (COE) of the cycle incorporating SO x removal is about 3% lower. Comparing these combined cycles to the sour gas water cycles discussed in our previous paper ( Chakroun and Ghoniem, 2015 ), it is evident that sour gas based oxy-combustion combined cycles generally perform better in terms of both technical and economical performance. Therefore, it is concluded that the best process cycle to use for this sour gas fuel to be the combined cycle with the SO x removal system. This high-efficiency cycle has the lowest COE out of all of the five cycles studied. [ABSTRACT FROM AUTHOR]

• Quest CCS facility has been operating since 2015 and has stored upwards of 6 million tonnes of CO2 permanently. • A comprehensive MMV plan is in place to monitor data conformance to model and containment. • 5 key seismic campaigns have occurred during the project and operate phase of the facility with 3 of these campaigns acquiring time-lapse datasets. • Optical Fiber cemented in place has been an effective technology to allow for more data collection at lower cost, lower exposure and higher data repeatability. • Processing enhancements have increased data quality. • Advancements in imaging and interpretation techniques are leading to better understanding of time-lapse seismic utility at quest. • DAS VSP life expectancy is likely coming to an end at quest as the plume grows. Surface seismic is now under assessment. • This paper provides an overview of time-lapse campaigns at quest with the purpose of covering many aspects of the monitoring strategy, data collection and improvements. In August 2015, CO 2 injection commenced at the Quest Carbon Capture and Storage (CCS) Facility located near Fort Saskatchewan, Alberta, Canada. Quest is a fully integrated CCS operation with a capture target of just over one million metric tonnes of CO 2 per year. CO 2 is injected into a deep saline aquifer, the Basal Cambrian Sandstone (BCS), at a depth of about two kilometers below ground. In order to demonstrate containment and conformance of the injected CO 2 , a Measurement, Monitoring and Verification (MMV) plan has been implemented. Multiple domains are monitored as part of the plan, including the atmosphere, biosphere, hydrosphere, geosphere, and wells. Time-lapse seismic methods are utilized primarily for conformance monitoring and secondarily for containment monitoring of the CO 2 plume within the Geosphere domain. These methods currently include 3D surface seismic (SEIS3D), 2D surface seismic (SEIS2D) and 2D multi-azimuth walk-away borehole vertical seismic profiles with distributed acoustic sensing (VSP2D). The first goal of this paper is to summarize the role of seismic, subsurface modeling efforts and the different baseline and monitor datasets that have been acquired at the Quest CCS Facility. The second goal is to describe the current Quest time-lapse strategy. Five key seismic acquisition campaigns have occurred at Quest through the pre- and post-start of injection periods, including an initial SEIS3D acquisition, a pre-injection baseline VSP2D acquisition, and three monitor VSP2D acquisitions. SEIS2D acquisitions have also been acquired as part of two of the most recent monitor campaigns. All campaigns have occurred over the winter season, to facilitate surface access, minimize impact on the land and farming/harvest activities, and to ensure maximum repeatability. Time-lapse seismic methods yield an image of the CO 2 that is injected into the BCS pore space, displacing some of the brine in the saline aquifer. Since the injected CO 2 is more compressible and less dense than brine, the velocity of seismic primary-waves traveling through the BCS is reduced in those places containing CO 2 and remain unchanged elsewhere. Petrophysical data from the injection wells (IWs) were used to calculate the acoustic properties of the BCS. Gassmann fluid substitution was used to model the effect of CO 2 saturation on the expected seismic response. Modeling showed that differences in the seismic images of the BCS obtained before and during CO 2 injection should be seen in two characteristics ways: 1) Travel-times across the BCS increase due to the slower primary-wave velocity inside the BCS. 2) Reflections from the base of the BCS become stronger as the impedance contrast with the underlying granite basement increases. The contrast between the BCS and underlying basement is much larger than between the BCS and the overlying sediments. The large contrast between the BCS and basement produces a prominent reflection which is easily mapped during baseline and monitor surveys and is more practical for amplitude extractions. Modeling also indicated that, while the acoustic changes are sufficient to define the CO 2 front qualitatively, it is unlikely that they can be used to quantify the distribution of CO 2 saturations within the plume. The initial time-lapse seismic strategy called for SEIS3D to be employed after a few years of injection. Borehole distributed acoustic sensing (DAS) VSPs were proposed as a cost-effective and flexible alternative to SEIS3D while injection volumes are small. With the optical fiber cemented in place behind the casing, data can be acquired at any time without suspending injection, something not achievable with conventional VSPs that use retrievable downhole geophone arrays. The effectiveness of VSPs is inherently dependent upon the injection volume, plume offset from the IWs and acquisition geometry. After evaluating the concentric plumes predicted from dynamic modeling results and considering the acquisition logistics at the Quest CCS well sites, a VSP2D program was executed. In 2017 and 2019, SEIS2D was recorded in addition to the VSP2D surveys. Surface geophones were deployed along the VSP2D shot locations, recording a pseudo-3D or cross-spread survey. SEIS2D will be evaluated as another seismic method to potentially monitor CO 2 plume development in the BCS. [ABSTRACT FROM AUTHOR]

• DTS allows real-time monitoring of subsurface conditions • DTS and warmback analysis can show presence of fluids in formations • Warmback analysis can be useful to detect fluid migration along vertical wellbore • Arrival of CO2 plume can be detected by DTS at monitoring well A Distributed Temperature Sensing (DTS) system, along with a five-level, behind-casing pressure sensing array was installed as part of the Midwest Regional Carbon Sequestration Partnership (MRCSP) large-scale carbon dioxide (CO 2) storage test in a depleted Niagaran pinnacle reef oil reservoir in Northern Michigan. The reef is being monitored during its initial reservoir fill-up period as CO 2 is being injected to raise the reservoir pressure for enhanced oil recovery (EOR). DTS data are analyzed with results from the initial injection of ˜101,000 metric tons of CO 2 , injected between January 2017 and December 2018. This paper discusses the results of real-time DTS combined with multi-level pressure monitoring. The collection, processing, and interpretation of large amounts of data from fiber-optic-based DTS provides an opportunity to obtain high-resolution information on migration of CO 2 in the reservoir. [ABSTRACT FROM AUTHOR]

Mechanism of CO 2 adsorption on amine loaded SBA-15 sorbents with varying amine coverage has been assessed using thermogravimetric analysis (TGA) and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). TGA study showed that sorbent adsorption capacities increased by 122–153% with CO 2 concentrations (5–80%) in the gas at 50/75 °C. The DRIFTS studies indicate that low amine loaded sorbents exhibit higher uptakes with an increase in CO 2 concentrations which is attributed to the mode of CO 2 adsorption i.e. 1:1 CO 2 to amine forming carbamic acid. At higher amine loadings CO 2 is adsorbed following the 1:2 CO 2 to amine forming carbamate-ammonium ions pair resulting in lower adsorption capacities per amine site. The studies also showed an increase in carbamic acid formation with pressure from 100 to 500 kPa at low amine loadings and both carbamic acid and carbamates at higher amine loadings. The paper provides insights into the mechanistic understanding of CO 2 adsorption behaviour of the varyingly covered amines on the SBA-15 support with a change in concentration and pressure of CO 2 . The current work presents the conditions to alter the CO 2 adsorption mechanism on amine sites with potential application in CO 2 conversion to chemicals. [ABSTRACT FROM AUTHOR]

The objective of this study is to evaluate the sensitivity of Distributed Temperature Sensing (DTS) data to detect CO 2 leakage along an injection well casing. This paper describes the relationship between the CO 2 leakage rate and temperature response at DTS locations, and the method and numerical model used for understanding such a relationship. The uncertainties in the parameters are propagated to the interpretation of DTS measurements, which may lead to false positive and false negative identifications of CO 2 leakage. We propose to identify CO 2 leakage by analyzing both temperature history plots at selected vertical locations as well as the vertical temperature profiles at different times. The analysis should be combined with numerical simulations for the estimation of leakage rates. In addition, leakage needs to be confirmed by data from a warm-up test (temperature recovery after injection of cold CO 2 is stopped) to minimize the probability of false identifications. [ABSTRACT FROM AUTHOR]

The potential for implementing carbon capture in Nordic industry sectors such as iron and steel production, cement and lime production, onshore and offshore oil and gas activities and pulp and paper production has been addressed. In Norway, much of the CO 2 is emitted from the oil and gas sector. In Denmark the power and heat production comprises the largest share while in Sweden and Finland biomass based industry such as power and heat production in CHP plants and pulp and paper production generates most of the CO 2 emissions. Iceland emits most CO 2 from metal industry, in particular non-ferrous metal production. In a Nordic perspective, the oil and gas industry has a high potential for implementation of CCS along with iron and steel production and cement production. Only cement production and pulp and paper production industries seem to have potential to decrease the CO 2 emissions close to zero. Capturing biogenic CO 2 from pulp and paper production could remove CO 2 from the atmosphere and create a carbon sink. Clustering of emission sources and implementing a joint CCS (Carbon Capture and Storage) chain could possibly lower the CCS unit costs. Process alterations and industry specific solutions due to the implementation of CCS in industry could improve existing processes. However, the possibility for carbon leakage could decrease the competitiveness of Nordic industries significantly as long as there is no global agreement on reduction of CO 2 emissions. [ABSTRACT FROM AUTHOR]

It is proposed that very low permeability formations are possible candidates for CO 2 sequestration. Further, experimental studies have shown that shale formations have huge affinity to adsorb CO 2 , the order of 5 to 1 compared to the methane. Therefore, potential sequestration of CO 2 in shale formations leading to enhanced gas recovery (EGR) will be a promising while challenging target for the oil and gas industry. On the other side, hydraulic re-fracturing treatment of shale gas wells is currently gaining more attention due to the poor performance of shale gas reservoirs after a couple years of production. Hence, investigating and comparing the performance of CO 2 -EGR with the re-fracturing treatment is essential for the future economic viability of depleted shale gas reservoirs. This paper presents a systematic comparison of the effect of these two processes on improving gas production performance of unconventional reservoirs, which is not well understood and has not been studied thoroughly in the literature. In this paper, a shale gas field data has been evaluated and incorporated in our simulations for both CO 2 -EGR and re-fracturing treatment purposes. Numerical simulations are performed using local grid refinement (LGR) in order to accurately model the non-linear pressure drop. Also, a dual-porosity/dual-permeability model is incorporated in the reservoir simulation model. Further, the uncertainties associated with inter-related set of geologic and engineering parameters are evaluated and quantified for re-fracturing treatment through several simulation runs. This comprehensive sensitivity study helps in understanding the key reservoir and fracture properties that affect the production performance and enhanced gas recovery in shale gas reservoirs. The results showed that re-fracturing treatment outperforms CO 2 -EGR due to the pronounced effect on cumulative methane gas production. Moreover, the sensitivity analysis showed that the characteristics of reservoir matrix including permeability and porosity are the most influential parameters for re-fracturing treatment. The findings of this study recommend hydraulic re-fracturing of shale reservoirs at first for enhancing gas production followed by CO 2 injection at a later time. This work provides field operators with more insight into maximizing gas recovery from unconventional shale gas reservoirs using re-fracturing stimulation, CO 2 injection, or a combination of both methods. [ABSTRACT FROM AUTHOR]

Carbon dioxide is one of the main if not the most potent greenhouse gases responsible for climate change. Scientists put great efforts to tackle this problem and carbon dioxide capture seems to be a promising solution. The present study proposes a novel method of carbon dioxide capture using black liquor, a side stream from the paper and pulp industry. Its content in sodium hydroxide makes it an attractive candidate for carbon dioxide capture via carbonation. The black liquor was prepared from oat husks, a non-woody biomass, using the soda-pulping process. To estimate its carbon dioxide absorption capacity, a mixture of nitrogen and carbon dioxide (70:30%) was sparged into a bubble column reactor and computational fluid dynamics simulations of this setup were used to evaluate the mixing process. The formation of carbonate and bicarbonate ions throughout the carbonation process was followed using a Fourier-Transform Infrared (FTIR) probe and a pH meter. The absorption capacity was measured from the weight increase of the reactor. It was found to be around 30 g of carbon dioxide/L of black liquor. The carbonate and bicarbonate species in black liquor before and after carbonation were further characterized with 13C Nuclear Magnetic Resonance (NMR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and optical microscopy. Using industrial side-streams might enable an economically feasible process without the need for production of virgin absorbents or their recovery. Furthermore, this capturing process, which is performed at atmospheric conditions might reduce the overall energy consumption. The results demonstrated that black liquor could be an attractive absorbent for carbon dioxide, paving the way for a circular and resource-efficient economy. • Carbon dioxide capture using black liquor as the absorbent. • Non-woody black liquor captures 30 g of carbon dioxide per liter. • Sodium carbonates and bicarbonates were formed. • Bubble column stirred reactor for carbon dioxide absorption. [ABSTRACT FROM AUTHOR]

• Predicting puncture size probability distribution for CO 2 pipelines is challenging due to sparse failure statistics • A reliable puncture size probability distribution requires over 100 sample data • Bootstrapping improves puncture size probability distribution estimation for CO 2 pipelines • CO 2 pipelines are more likely to experience smaller size punctures compared to NG pipelines The safe operation of pressurised CO 2 pipelines is key to the success of Carbon Capture and Storage as a viable means for tackling global warming. However, given their relatively small number currently in operation, the confident prediction of their puncture size failure probability and how it compares with hydrocarbon pipelines are fundamentally important questions that must be resolved. This paper presents the development and application of a robust statistical analytical technique for the confident prediction of the puncture failure size probability distribution for CO 2 pipelines. The above involves fitting statistical distributions to the historical puncture size failure data using the Maximum Likelihood Estimator (MLE). The minimum acceptable sample size sufficient for acquiring a reliable MLE is determined by calculating the mean squared error of the MLE as a function of the data sample size. To improve the estimation confidence, given the scarcity of historical failure data, the bootstrapping method is employed to obtain the 95% confidence interval of the MLE. The application of the above technique to pressurised CO 2 and hydrocarbon pipelines indicates that as compared to the latter, CO 2 pipelines are more likely to experience smaller puncture size failures (e.g. ≤ 50 mm), thus resulting in smaller magnitude but more prolonged releases. This directly impacts the preventive and emergency response planning required especially in the case of buried CO 2 pipelines where small leaks can remain undetected for long periods. [ABSTRACT FROM AUTHOR]

• System boundary choices vary widely in literature on bioenergy with CCS. • System boundary choice can be a major determiner of estimated CO 2 avoidance cost • Costs and lifecycle greenhouse gas estimated for bioenergy with CCS at cement plant • System boundary choice varied net CO 2 estimates from -660 to 16 kg CO 2 (eq)/t cement • Aligned boundaries shrinks avoidance cost range from 48-321€ to 157-193€/t CO 2 (eq) Negative emission technologies such as biomass with carbon capture and storage (bioCCS) may become an important instrument to limit global warming. Currently, estimates of CO 2 avoidance cost for bioCCS vary widely. Using a case study of a cement plant, this paper illustrates how this variance is partially attributable to the system boundary choices made by modellers. The estimated avoidance cost for the bioCCS-in-cement plant ranged from 48-321€ 2017 /t CO 2 (eq) and the net CO 2 (eq) from -660 to 16 kg CO 2 (eq)/t cement, without any change in the technological model, equipment and input costs, or lifecycle emissions, but by changing the system boundaries used for cost and emission accounting, reflecting the different boundaries seen in bioCCS literature. To allow for more comparable bioCCS cost estimates, studies should always account for costs and emissions of both biomass production and the full chain of carbon capture, transport, and permanent storage, as both are fundamental to the role of bioCCS as a potential "negative emission technology". We also advocate for clear decomposition of metrics, separation of "avoided emissions" from physical flows of greenhouse gases; and explicit consideration of the temporality of the bioCCS system. With these guidelines, the range of avoidance cost of the bioCCS-in-cement plant shrinks to 157-193€ 2017 /t CO 2 (eq) for near-term estimates and to 89-107€ 2017 /t CO 2 (eq) for longer-term estimates. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we have analyzed carbon dioxide (CO 2 ) capture and hydration using enzyme inspired complexes. Particularly, efforts have been made to investigate the carbonic anhydrase (CA) mimic complexes discovered in the last five years. CA, a well known zinc containing enzyme, can hydrate CO 2 in unprecedented rate ( K cat  = 10 6  s −1 ). It has been recently used in commercial CO 2 capture unit or blended with amines to enhance CO 2 capture and ease the stripping. However, the uses of the native enzyme face several intrinsic difficulties such as thermal stability, pH stability and storage issues etc. Therefore, mimicking the active site of CA is of enormous interest among the scientific communities. These enzyme inspired complexes not only reproduce similar activities of CA but also thermally stable over a broad range of temperature and robust at drastic conditions. In this attempt we have precisely summarized the zinc and non-zinc complexes, de-novo enzymes along with the importance of supramolecular-scaffolds during mimic design. The current use and shortcomings of these enzyme mimics in industrial prospective are also discussed. Finally, the development of ab initio and classical molecular simulation methods for modeling enzyme mimics are discussed for the futuristic design of next generation CO 2 capture catalyst. [ABSTRACT FROM AUTHOR]

• The potential integration routes of CO 2 capture technologies with renewables are discussed. • Renewable energies can play a vital role to achieve net-zero or negative CO 2 emissions. • Novel capture processes may address the intermittent nature of renewable energy sources. • Renewable integration could minimize/stop carbon capture retrofits from steam consumption. • Net-zero emission target would be realizable by leveraging negative emission technologies. This paper broadly reviews the integration of different renewable energy sources including solar, bioenergy, wind, and geothermal energy with CO 2 capture processes and evaluates the possible contribution to achieve net-zero or negative CO 2 emissions. Each renewable energy integration option possesses advantage points, which may help reducing the CO 2 capture cost and potentially realize the net-zero or negative emission ambitions. In power sector, renewable energy integration encounters a number of challenges such as high upfront investment, large fluctuation in the CO 2 capture rate, and electricity cost. Nonetheless, those drawbacks can be minimized by flexible designs that would optimize renewable energy contribution with steam extraction to improve power plant efficiency and install on/off function to exploit low electricity price periods and to alleviate the effect of the intermittent nature of those renewable energy options. Although, many integration scenarios have been proposed in literature, there is a lack of consideration with recently advanced CO 2 capture technologies in the hard-to-abate emission sectors such as heavy industries and heavy transport. Renewable energy integration may also bring a promising revenue to advance the ambitious goal of direct air capture (DAC) technologies due to the flexibility in location and operation modes, nevertheless, it draws a little attention. In this analysis, the advantages and disadvantages of each renewable energy source when it is integrated into a CO 2 capture process are discussed and thereby potential research directions are identified. It is emphasized that renewable energy integration could autonomize carbon capture retrofits to provide convenience to power/industrial plant operators and/or to realize the ambitions of installing independent and scalable DAC systems on inexpensive land or in vicinity of the CO 2 storage/utilisation sites. [ABSTRACT FROM AUTHOR]

• Stakeholders clustering is crucial for cost-effective implementation of CCUS projects. • Amongst three possible clusters, the Eastern one is the most feasbile. • EOR is considered, but with focus on CO2 retention rather than extra oil recovery. • High available theoretical storage capacity allows to consider cross-border options. Carbon Capture and Storage is a concept that is not yet fully implemented largely because of the high costs. Clustering of industrial stakeholders is imposed as a measure for cost reduction. All relevant emitters, possible transport routes, including existing gas pipeline corridors, and their geographic location in relation to potential storage locations are assessed in this paper. Site availability and CO 2 storage capacity are examined, summarizing all study results gathered under the Strategy CCUS project. The CO 2 enhanced oil recovery is being studied for CO 2 storage rather than extra oil recovery. As logical choices, three clusters were recognized. Only less expensive, onshore injection was taken in consideration for assessment of early (economic) feasibility in the Adriatic, Central, and Eastern clusters. Because of the shorter distance between CO 2 emitters and injection sites, the Eastern and Central clusters are being investigated in more detail, despite the fact that the largest point source emitter is in the Adriatic region. Because of small number of point source CO 2 emitters and huge theoretical storage capacity, further research is needed to better assess the storage capacities as well as possibilities for development of cross-border projects. Based on previous research (particularly regarding the emitters), the number of facilities (fewer facilities, with more concentrated emissions), and the availability of storage objects, the Eastern cluster is recommended to be further studied as the next stage of Carbon Capture, Utilization and Storage cluster research and development in Croatia and nearby cross-border regions. [ABSTRACT FROM AUTHOR]

• NH 4 Cl is used to leach Ca2+ from FGD gypsum and can be used for seven times. • 1 ton of FGD gypsum absorbs 207 kg of CO 2 while producing 470 kg of CaCO 3. • High-purity CaCO 3 with different grain size, structure and morphology is successfully produced. • Carbonation parameters can affect the polymorphism of CaCO 3. Based on salt effect and the solubility equilibrium theory of insoluble electrolyte, the technological process of ammonia-enhanced desulfurization gypsum carbonation for CO 2 sequestration in NH 4 Cl-H 2 O system was studied, and calcium carbonate with different crystal phase and morphology was prepared in this paper. The results showed that the optimal conditions for the dissolution of Ca2+ included NH 4 Cl concentration of 4 mol/L, LS of 80:1 mL/g, leaching temperature and time of 50 °C and 60 min. The optimal leaching rate was 95.6%, and the leaching residue could be used for cement production. Regarding the optimum conditions of carbonation reaction, the addition amount of ammonia was 10 mL, CO 2 flow rate was 80 mL/min, reaction temperature was 40 °C, reaction time was 60 min, and the carbonation conversion rate was 98.54%. The filtrate of carbonation reaction could be recycled for 7 times, and the reaction efficiency was 50.8%. The optimal carbonated product was rhombohedral calcite, and the performance of the product was beyond the requirements of HG/T 2226–2010. The reaction conditions had little influence on the phase and microscopic morphology of the carbonated products. The proposed research is expected to be applied to the CO 2 sequestration and the utilization of desulfurization gypsum. [Display omitted] [ABSTRACT FROM AUTHOR]

Non-isocyanate polyurethanes (NIPU) or hydroxyurethanes from CO 2 sourced monomers were prepared via a non-toxic route, which avoided the toxic isocyanate utilization with an excellent conversion ratio of cyclic carbonate, higher than 95%. The hybrid NIPU was prepared in the presence of aminosilylated-mica, used as reinforcement to improve mechanical properties, besides keeping the charge dissipation. The improvement of mechanical, thermal and electrical properties by silylated mica is attributed to higher crosslinking density in the organosilicate network. (attributed to the interfacial urethane linkage between the -NH 2 on the surface of the mica and the cyclocarbonates). It has been demonstrated the feasibility to produce candidate materials for replacing epoxy-mica paper hybrid system by an alternative CO 2 derived non-isocyanate hydroxyurethane-mica powder system. This system holds two advantages: CO 2 long-term capture and a more simplified hybrid formation, since no vacuum pressure impregnation (VPI) is necessary, does resulting on lower energy consumption. [Display omitted] • Successful preparation of bisphenol A NIPU from CO 2 sourced monomers with excellent yield (> 95%) and hybrid NIPU in the presence of aminosilylated-mica (used as reinforcement to improve mechanical properties, besides keeping the charge dissipation), with no vacuum pressure impregnation (VPI) necessary. • Improvement of mechanical, thermal and electrical properties by the presence of silylated mica, due to a higher crosslinking density in the organosilicate network. • The hybrids of bisphenol A hydroxyurethane-silylated mica powder presented dielectric strength of 20.2 kV/mm and dielectric constant around 10.4 (1 kHz), which qualify this material as a potential candidate for insulating usage. • An equimolar ratio between isophorone diamine and bis-cyclocarbonate of bisphenol A presented the best performance according to swelling degree, gel content, water absorption, nanoindentation and thermal stability. [ABSTRACT FROM AUTHOR]

The need for carbon neutralization on a global scale necessitates innovative concepts for collecting, converting, and using carbon dioxide (CO 2), particularly the technology and materials that use CO 2 to convert biomass and nanobiomaterials as the basis of a circular bioeconomy. In recent years, CO 2 conversion reaction has paid great attention to CO 2 reforming and CO 2 methanation of CH 4 because of its advantages in using greenhouse gases (CO 2 and CH 4). In general, it can be utilized as a primary material for synthesizing novel products. In order to control and reduce CO 2 production, enhanced CO 2 capture and storage (CCS) technology has been fully developed to store CO 2 and reuse it in the valuable products, like materials and biomaterials preparation. In the present review article, the conversion of CO 2 to biomass energy is comprehensively discussed, emphasizing capture technology and post-combustion capture technology as promising methods of CO 2 emission reduction. Further, this paper summarizes CO 2 production and the comprehensive strategy of using CO 2 as helpful Energy. Moreover, the CO 2 removal provides low-carbon Energy while using its capture and storing technology to provide bioenergy, which is estimated to sustain the net zero CO 2 target. In addition, CO 2 capture and convert to biomass and then converted biomass into nanobiomaterials, their applications, preparation techniques and unique properties were reviewed. In general, this review focuses on converting carcinogenic CO 2 into useful biomass energy, conversion strategies, and the utilization of CO 2 into biomass and nanobiomaterials. [Display omitted] • Engineering approaches for the capturing and conversion of CO 2 to biomass are reviewed. • Carbon dioxide (CO2) capture using microalgae, absorbents, and membranes are explored in detail. • Capturing, conversion of CO 2 into biomass and combination with nanobiomaterials, were fully discussed. • The future perspective and utilization of CO 2 into biomass and nanobiomaterials as the medium of circular bioeconomy are summarized. [ABSTRACT FROM AUTHOR]

Reducing CO 2 emissions from the construction industry is the most imperative factor in the fight against climate change, which aims to reduce the average atmosphere temperature below 1.5 °C by the end of this century. Globally, the cement industry is responsible for approximately ∼7 % of CO 2 emissions. About 9.95 Gt/y of CO 2 was emitted by the construction sector as of 2019, making it the highest contributor. The construction sector is forecast to reduce its CO 2 emissions by 16 % by 2030, leading to net-zero emissions by 2050. Thus, several measures have been implemented to mitigate significant CO 2 emissions from the construction industry by capturing and utilizing CO 2. This paper reviews existing industrial-level CO 2 capture technologies in cement industries, such as amine scrubbing, oxy-combustion, direct capture, and calcium looping, as well as the costs and barriers associated with their use. Also presented a summary and comparison of utilizing CO 2 through accelerated mineral carbonation in cement-based materials, recycled aggregate, and calcium-rich solid waste. In addition to this, various commercialized technologies for mitigating CO 2 emissions (Carbon8, Calera Corporation, CarbonCure, Solidia, Blue Planet and Carbstone) and their methods of sequestering CO 2 as well as their technology readiness levels (TRL), %CO 2 uptake, and patent analysis for their technologies were discussed. [Display omitted] • Different CO 2 capture technologies such as amine scrubbing, calcium looping, Oxy-combustion capture, and direct separation were reviewed. • Sequestration of CO 2 through mineral carbonation in cement-based materials, was presented in detail. • Furthermore, a detailed report is presented on recent developments and the status of various commercial technologies (1) companies that manufacture binding agents for concrete (Solidia Technologies, CarbonCure and Carbstone Innovation) and (2) firms that manufacture synthetic aggregates (Blue Planet and Carbon8 Systems). [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses the current status of CCS in China, providing an update of current projects and past activities in research and development, and a brief overview of prospects for CCS deployment in China. CCS related research in China has been building from a focus on research and development and exploration of the technical considerations o f CCS potential in China in coordination with international partners. While large scale demonstration of integrated CCS projects is still at an early stage, there is significant knowledge and technical expertise that can be derived from ongoing pilot projects. These projects employ various mature technologies that may be integrated and scaled to facilitate demonstration and deployment of CCS in the future. In addition, China is increasingly exploring opportunities in CO2 utilization to drive and support deployment of CCS–this is also known as CO2 capture, utilization and storage (CCUS). This paper provides information on some of these key activities, including details of specific projects and a background of the regulatory and policy frameworks and international cooperation on CCS and CCUS in China. [Copyright &y& Elsevier]

Abstract: Large-scale, dedicated commercial biomass energy systems are a potentially large contributor to meeting global climate policy targets by the end of the century. We use an integrated assessment model of energy and agriculture systems to show that, given a climate policy in which terrestrial carbon is appropriately valued equally with carbon emitted from the energy system, biomass energy has the potential to be a major component of achieving these low concentration targets. A key aspect of the research presented here is that the costs of processing and transporting biomass energy at much larger scales than current experience are explicitly incorporated into the modeling. From the scenario results, 120–160EJ/year of biomass energy is produced globally by midcentury and 200–250EJ/year by the end of this century. In the first half of the century, much of this biomass is from agricultural and forest residues, but after 2050 dedicated cellulosic biomass crops become the majority source, along with growing utilization of waste-to-energy. The ability to draw on a diverse set of biomass-based feedstocks helps to reduce the pressure for drastic large-scale changes in land use and the attendant environmental, ecological, and economic consequences those changes would unleash. In terms of the conversion of bioenergy feedstocks into value added energy, this paper demonstrates that biomass is and will continue to be used to generate electricity as well as liquid transportation fuels. A particular focus of this paper is to show how climate policies and technology assumptions – especially the availability of carbon dioxide capture and storage (CCS) technologies – affect the decisions made about where the biomass is used in the energy system. The potential for net-negative electric sector emissions through the use of CCS with biomass feedstocks provides an attractive part of the solution for meeting stringent emissions constraints; we find that at carbon prices above $150/tCO2, over 90% of biomass in the energy system is used in combination with CCS. Despite the higher technology costs of CCS, it is a very important tool in controlling the cost of meeting a target, offsetting the venting of CO2 from sectors of the energy system that may be more expensive to mitigate, such as oil use in transportation. CCS is also used heavily with other fuels such as coal and natural gas, and by 2095 a total of 1530GtCO2 has been stored in deep geologic reservoirs. The paper also discusses the role of cellulosic ethanol and Fischer–Tropsch biomass derived transportation fuels as two representative conversion processes and shows that both technologies may be important contributors to liquid fuels production, with unique costs and emissions characteristics. [Copyright &y& Elsevier]

Abstract: Emissions from electricity generation will have to be reduced to near-zero to meet targets for reducing overall greenhouse gas emissions. Variable renewable energy sources such as wind will help to achieve this goal but they will have to be used in conjunction with other flexible power plants with low-CO2 emissions. A process which would be well suited to this role would be coal gasification hydrogen production with CCS, underground buffer storage of hydrogen and independent gas turbine power generation. The gasification hydrogen production and CO2 capture and storage equipment could operate at full load and only the power plants would need to operate flexibly and at low load, which would result in substantial practical and economic advantages. This paper analyses the performances and costs of such plants in scenarios with various amounts of wind generation, based on data for power demand and wind energy variability in the UK. In a scenario with 35% wind generation, overall emissions of CO2 could be reduced by 98–99%. The cost of abating CO2 emissions from the non-wind residual generation using the technique proposed in this paper would be less than 40% of the cost of using coal-fired power plants with integrated CCS. [Copyright &y& Elsevier]

Abstract: Aqueous ammonia can be used to capture CO2 from flue gas of coal-fired power plant with quick reaction rate, high removal efficiency, and high loading capacity of CO2. It is thought to be a promising technology. However, the CO2 absorption rate, diffusion rate and VLE (Vapor liquid equilibrium) in aqueous ammonia have still been rarely researched. More research is necessary for these characters of ammonia solution as CO2 absorbent. The paper will focus on the fundamental characteristics of CO2 in aqueous ammonia. A series of tests were conducted in a semi-batch reactor that has been developed in this paper. CO2 removal efficiencies at different concentrations of aqueous ammonia have been studied in the similar operation conditions to compare their basic characters in the CO2 absorption process. And a small wetted wall column (WWC) with a contact area of about 41.45 cm2 was also built for the study of the absorption rate, diffusion, and solubility of carbon dioxide in the aqueous solution. In the paper, reaction rate and overall gas transfer coefficient were studied. The concentration of ammonia ranges from 1, 5, 10 to 15. CO2 and N2 are used to simulate the flue gas. The concentration of CO2 ranges from 5, 10, 15, to 20%. The reaction temperatures are 20 ∘C and 40 ∘C. It is indicated in this paper that the best concentration of aqueous ammonia should be selected from 5% to10%. And aqueous ammonia has a high Flux in WWC, which is three times higher than that of MDEA+PZ, under the same condition. It is also found that is appropriate to be used in the mass transfer process of the carbon dioxide absorption by aqueous ammonia. Alls of these experiments established foundation for the further study of CO2 removal by ammonia. [Copyright &y& Elsevier]

Abstract: Carbon dioxide capture and storage (CCS) involves the capture of CO2 at a large industrial facility, such as a power plant, and its transport to a geological (or other) storage site where CO2 is sequestered. Previous work has identified pipeline transport of liquid CO2 as the most economical method of transport for large volumes of CO2. However, there is little published work on the economics of CO2 pipeline transport. The objective of this paper is to estimate total cost and the cost per tonne of transporting varying amounts of CO2 over a range of distances for different regions of the continental United States. An engineering-economic model of pipeline CO2 transport is developed for this purpose. The model incorporates a probabilistic analysis capability that can be used to quantify the sensitivity of transport cost to variability and uncertainty in the model input parameters. The results of a case study show a pipeline cost of US$ 1.16 per tonne of CO2 transported for a 100km pipeline constructed in the Midwest handling 5 million tonnes of CO2 per year (the approximate output of an 800MW coal-fired power plant with carbon capture). For the same set of assumptions, the cost of transport is US$ 0.39 per tonne lower in the Central US and US$ 0.20 per tonne higher in the Northeast US. Costs are sensitive to the design capacity of the pipeline and the pipeline length. For example, decreasing the design capacity of the Midwest US pipeline to 2 million tonnes per year increases the cost to US$ 2.23 per tonne of CO2 for a 100km pipeline, and US$ 4.06 per tonne CO2 for a 200km pipeline. An illustrative probabilistic analysis assigns uncertainty distributions to the pipeline capacity factor, pipeline inlet pressure, capital recovery factor, annual O&M cost, and escalation factors for capital cost components. The result indicates a 90% probability that the cost per tonne of CO2 is between US$ 1.03 and US$ 2.63 per tonne of CO2 transported in the Midwest US. In this case, the transport cost is shown to be most sensitive to the pipeline capacity factor and the capital recovery factor. The analytical model elaborated in this paper can be used to estimate pipeline costs for a broad range of potential CCS projects. It can also be used in conjunction with models producing more detailed estimates for specific projects, which requires substantially more information on site-specific factors affecting pipeline routing. [Copyright &y& Elsevier]

This paper reports the carbon dioxide detection in silicon-Pyrex high pressure microfluidic devices mimicking geological conditions encountered in deep saline aquifers using an in situ infrared optical sensor. The middle infrared source inserted inside the microchannel is based on infrared emission from Dy 3+ sulfide glass fibers. The broad emission of the Dy 3+ doping in infrared fibers is used to directly probe the CO 2 thanks to the perfect overlap between the rare earth emission centered at 4.4 μm and the CO 2 absorption band located at 4.3 μm. CO 2 and water were clearly distinguished when using segmented flow on chip at pressures ranging from 4.5 to 6 MPa. These results demonstrate the feasibility of the infrared optical detection of other gases displaying absorption bands in the middle infrared domain for further developments of gas sensors, which can find applications in geological media monitoring and microfluidics. [ABSTRACT FROM AUTHOR]

This paper describes how a downhole CO 2 chemical sensor was prepared for use in determining the concentration of CO 2 in water, particularly in harsh, high-pressure environments such as those found in geological formations considered for the geologic storage of CO 2 . The sensor consisted of a pair of Ir/IrO x and Ag/AgCl electrodes, a gas-permeable membrane, a bicarbonate-based internal electrolyte solution, and porous stainless steel as supporting material. The sensor was tested in the solution with different concentrations of CO 2 and displayed very good CO 2 sensing performance under pressures of 1000, 2000, and 3000 psi. A linear relationship between the sensor response potential and the logarithm of the CO 2 concentration was obtained for the sensor under different pressures. Reproducibility of the sensor was examined and the results indicated that the sensor displayed excellent reproducibility. CO 2 /brine core flooding tests were carried out to evaluate the performance of the CO 2 sensor in simulate CO 2 storage process. The results indicated that the sensor could detect CO 2 movement in the tests. Further studies showed that the sensor could be reused by brine flooding after CO 2 /brine flushed the core. The results of the core flooding tests demonstrated that the sensor had potential application for CO 2 monitoring in carbon storage. [ABSTRACT FROM AUTHOR]

This paper applies mathematical programming and superstructure-based optimization approaches to design multi-stage membrane systems for CO 2 capture, with the aim to systematically determine the optimal number of membrane stages, membrane areas, power requirements, the location of recycle streams, and operating conditions that satisfy desired CO 2 recovery−purity value pairs ranging from 90 to 98% at minimum total cost. A superstructure that embeds several candidate configurations is represented as a NLP model which is used to investigate how these ranges of target values affect the optimal number of stages, membrane areas, operating conditions, and total cost. The results indicate that the optimal number of stages depend strongly on the desired CO 2 purity. For CO 2 purity ranging from 90 to 93%, the optimal configuration involves two stages and one recycle stream; from 94 to 96%, the optimal configuration involves three stages and two recycle streams; and finally, from 97 and 98%, the optimal configuration involves all the four stages proposed in the superstructure keeping the two recycle streams. For the same design specifications, the obtained process configurations compete not only with reference cases of multi-stage membrane systems in terms of total cost, but also with absorption-based CO 2 capture processes in terms of energy requirements. [ABSTRACT FROM AUTHOR]

Fossil fuels are used widely for energy production and are likely to continue to play a major role world wide for many years to come. Much work has been done on the technology for capturing CO 2 from gaseous industrial effluent. For large-scale applications like coal or natural gas-fired power plants, using amine solvents to capture post-combustion CO 2 is the most mature CO 2 capture technology. This technique can be used to retrofit existing plants by treating the flue gas after combustion. This paper details a dynamic mathematical model for the absorber column constructed from first principles. The loss of MEA through oxidative degradation has been quantified here for the first time and this is currently not possible using commercial packages. Reaction rate kinetics have been employed to predict the accumulation of oxidation products which is limited by the incomplete knowledge of the dominant reactions between O 2 and MEA. When research has produced more detailed information about the products formed during this oxidation, it can be inserted easily into the model. Validation has been performed using data from the CSIRO PCC pilot plant at AGL Loy Yang. A limited parametric study of the impact of operating conditions on oxidation was performed. [ABSTRACT FROM AUTHOR]