The pre-salt oil and gas production in Brazil faces a significant challenge due to the high CO2 content in these reservoirs. Approximately 600,000 t of CO2 are reinjected monthly in the reservoirs, but the increased production of CO2 will demand alternatives for sequestration. Experiments and pilot projects have demonstrated the viability of CO2 sequestration through the mineralization method in basaltic rocks. Here, we present a study aimed at demonstrating the feasibility of using the volcanic rocks of the Cabiúnas Formation, located at the base of the pre-salt section in shallow waters of the Campos Basin, for CCS projects. We used legacy data to determine the regional characteristics and porosity distribution of the volcanic sequence to assess the feasibility of geological sequestration in this region. Our estimates demonstrated that the Cabiúnas flood basalts have a good to excellent storage capacity. The modeling of a 31km2 hypothetical reservoir with a thickness of 300 m in the upper part of the sequence above the Badejo Field revealed a storage estimate of 16–47 Mt. The technical aspects discussed in this study provide valuable insights that can help with the development of future CCS projects in the volcanic rocks of this petroleum province.

Carbon capture from the calcination process in Kraft pulp mills, also known as sulphate pulp mills, has potential as a part of carbon capture and storage (CCS) infrastructure deployment. Growing concern of climate change is increasing the interest for so-called negative emission technologies (NETs), and large emission points have great potential. However, among other factors, lack of financial incentives, trade-off with investments in existing products, and the necessity of large infrastructure that stretch across country borders, constrain deployment. This study investigates two concepts for carbon capture in combination with lime kilns in Kraft pulp mills: oxyfuel combustion and electric arc plasma calcination. The results from the modelling of six configurations show that carbon capture from the calcination process with these technologies can be made with comparatively low additional energy demand. Sulphate pulp production from Kraft pulp mills, which use lime kilns, is increasing in Europe and in the world. Therefore, there is large potential for capture of CO2 from these alternative calcination technologies, both as a first step towards and as a part of a large-scale deployment of CCS and bioenergy with CCS (BECCS).

In the absence of abiotic sources of CO2, variation in pCO2 and pO2 is expected to be inversely correlated in the water column due to biogenic processes. It has previously been suggested to use this correlation for leakage monitoring of offshore geological carbon storage (GCS) sites. In this study the aim is to investigate the extent of this correlation in ocean water masses with different origin and history in the Norwegian Sea, as well as in water masses in the vicinity of an active hydrothermal vent field at Mohn's Ridge, where pH is used as a proxy for pCO2. Over a hydrothermal vent site, a strong correlation between pH and pO2 is observed from 0 to 1700 m, whereas at depths >1700 m there is no correlation, likely due to CO2 emissions from the hydrothermal vents. However, at a reference site nearly 200 km from the hydrothermal vents, the intermediate Arctic water masses (700 – 1600 m depth) also show pH-pO2 correlations that are inconsistent with biogenic processes, but less pronounced compared to the hydrothermal vent site. These findings show that the suitability of this monitoring strategy will depend on a thorough site-specific evaluation of pH/CO2 and O2 relationships of relevant water masses.

The CO2 desorption performance of N-methyldiethanolamine(MDEA)-Tetramethylammonium glycinate ([N1111][Gly]), MDEA-1-butyl-3-methylimidazolium lysinate ([Bmim][Lys]) aqueous solutions was investigated. The influences of amino acid ionic liquids (AAILs) type and AAILs concentration on CO2 desorption were demonstrated on the basis of experiments. The corrosion characteristics of 20# carbon steel in the MDEA-AAILs-CO2 aqueous solutions were also determined, and the effects of temperature, AAILs concentration, AAILs type, and CO2 loading on the corrosion rate were analyzed. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance carbon spectroscopy (13C NMR) and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) characterization were used to evaluate the CO2 desorption mechanism and corrosion mechanism, respectively. It is found that AAILs have a good performance in the desorption process and they can effectively reduce the corrosion rate of amine aqueous solution.

Carbon capture, utilization and storage (CCUS) is currently the most potential cutting-edge emission reduction technology in China to achieve the vision of carbon neutrality. The industrialization of CCUS faces multiple challenges such as high cost, technical security and public acceptance, but the lack of mature business model and corresponding incentive policies is the main restrictive factor affecting the industrialization of CCUS technology. Therefore, exploring a feasible CCUS business model and formulating relevant incentive policies are of great significance for promoting the commercial deployment of CCUS and achieving the national carbon neutrality goal. Focusing on coal-fired power plants, this paper uses the system dynamics method to compare and analyze two different CCUS business models from the perspectives of economy, technical feasibility and emission reduction benefits, and evaluate the system operation effects under different incentive policy scenarios. The research results show that the vertical integration model is the most potential CCUS business model in China at present, and different incentive policies will cause different changes in the CCUS system. Based on the research conclusions, this paper puts forward suggestions such as formulating differentiated power generation quota subsidy policies and actively developing the carbon emission trading market.

A detailed 1-D non-isothermal model of moving beds for micro-encapsulated carbon sorbents (MECS) is developed in this study with sodium bicarbonate as the encapsulated sorbent. A rigorous capsule model is also developed and integrated with the bulk phase model leading to a multi-scale reactor model. A heat exchanger embedded in the regenerator is considered to provide the heat required for sorbent regeneration along with the heat input from direct steam. A new correlation for the heat transfer coefficient for heat exchange between the embedded heat exchanger and the moving solids is used. A plant-wide model of the capture system is developed with the absorbers, regenerators, heat recovery systems and the balance of the plant. Several sensitivity studies are conducted evaluating the impact of operating and design variables. An economic model of the process is developed. Key design and operating variables are optimized for minimizing Equivalent Annual Operating Cost (EAOC). Optimal EAOC of the moving bed reactor using MECS with encapsulated sodium carbonate is found to be about 8% better compared to the traditional MEA-based CO2 capture for similar extent of heat recovery. For +50% uncertainty in the capital costs of the moving beds, the moving bed technology using MECS studied here is found to result in about 3% higher EAOC than MEA while for -50% uncertainty in capital cost of moving beds, EAOC for the moving bed process is found to be about 19% lower than the MEA-based capture. Finally, the impact of part load operation on the economics of the capture system is evaluated.

A many times heard mantra of solvent degradation management in amine-based post combustion capture is “keep the solvent clean” to minimize solvent consumption. It is assumed that the amine losses would decrease by the removal of metals, degradation products, and reactive trace components which are captured from the flue gas, like NO2 (as potentially driving components of the amine degradation besides dissolved O2). However, this theoretical hypothesis – based on results from laboratory experiments typically generated with fresh amines – disregards the complexity of the solvent matrix, interaction of potential metal catalysts with degradation products and oxidizing agents, and specific chemical requirements which must be fulfilled before a degradation mechanism can proceed. Degradation of the solvent CESAR1 (aqueous solution of 3.0 molar 2-amino-2-methylpropan-1-ol (AMP) and 1.5 molar piperazine (PZ)) is investigated in a unique long-time test campaign (testing time up to now 40 months; 24/7 operation) without replacement of the solvent inventory at the capture pilot plant at the lignite-fired power plant in Niederaussem. Three solvent management strategies with different effect mechanisms are investigated and evaluated: (a) removal of only anionic compounds and trace elements (within 75 days solvent inventory treated two times) and anionic as well as cationic compounds and trace elements (114 days, inventory treated four times) from the solvent by ion exchange, (b) adsorptive removal of trace elements from the solvent by active carbon in 35% of the operating time, and (c) removal of >80% NO2 by flue gas pretreatment with thiosulfate/sulfite solution (dosing for 2,000 h). The results of the testing program clearly show that “solvent cleanliness” is not a well-defined parameter and that results from laboratory tests, tests without fully representative industrial flue gasses, and short-term testing of monoethanolamine cannot be generalized for other solvents and industrial application. These results showcase that specific degradation management considering solvent, capture plant and flue gas quality is reasonable. Overshooting efforts for solvent management are contra-productive and produce unnecessary waste streams, efficiency losses and costs.

Carbon sequestration in geologic reservoirs is a proven method for reducing carbon dioxide (CO2) emissions from industrial point sources. Subsurface deltaic deposits are attractive candidates for CO2 storage projects due to their common occurrence as host to significant hydrocarbon and hydrologic resources, and are highly prospective for subsurface storage of large volumes of CO2. This research informs subsurface passive margin deltaic reservoir characterization and fluid flow performance for geologic carbon storage. The objective of this research is to create a high-resolution geocellular digital model that honors both the large-scale stratigraphic architecture and local vertical and lateral facies heterogeneity represented in deltaic environments of deposition. We present a novel approach to reservoir model generation by utilizing a previously generated meter-scale physical flume sand tank analog experiment to represent realistic deltaic stratigraphic architectures and facies distributions. The result is an extremely high-resolution geologic model that can be used for a variety of applications, including single and multiphase fluid flow simulation. An application is presented using the example model to simulate buoyant fluid (CO2) migration and resulting saturation distribution. Results emphasize the importance of recognizing sequence stratigraphic architectures in deltaic depositional settings for predicting CO2 migration and retention (storage capacity).

Carbon capture, utilisation and storage (CCUS) has gained prominence as one of a suite of technologies needed for mitigating the urgent threat posed by climate change. Despite the significance of CCUS technologies to a multitude of climate mitigation scenarios, research has identified a series of challenges to deployment, ranging from cost overruns and technical failures to public opposition. Research has widely documented the range of techno-economic challenges impacting the feasibility of individual technologies. However, a growing body of research calls for the feasibility of CCUS to be assessed more holistically, with greater focus on systemic, societal and other non-technical issues. Through a meta-review of 22 recent multidisciplinary review papers on CCUS, we identify and explore a comprehensive set of challenges impacting CCUS deployment. The results show a continued focus on the techno-economic dimensions within literature. However, the meta-review also unfolds a series of issues receiving less attention in literature, from organisational and environmental challenges to issues of legitimacy. Overall, this paper contributes to a broader understanding of the critical challenges facing CCUS projects in the coming decade and provides a framework for a more holistic assessment of climate mitigation technologies such as CCUS.

Hydrate-based CO2 sequestration (HBCS) is a new concept to store a huge amount of CO2 in geological sediments in the form of crystalline solids. This technique can address several environmental challenges of the current geologic carbon sequestration approaches. This study aims to evaluate and compare the characteristics and kinetics of CO2 hydrate formation and dissociation in the porous medium (three-phase) and bulk (two-phase) conditions at different CO2-water ratios. The experimental results indicate that the pressure drops and consequently hydrate nucleation and growth are limited in the porous medium due to the presence of solid particles, limited CO2 mass transfer, and heat transfer. Calculation of CO2 mass consumption and rate of gas uptake during hydrate formation also support the limited CO2 consumption and gas uptake rate in the porous medium, compared to the bulk condition. The calculated driving force for each test condition suggests its critical importance in the kinetics of CO2 hydrate formation. On the other hand, limited CO2 diffusion to the aqueous phase, hydrate nucleation at the solid-CO2-water interface, and better protection of newly formed hydrates are among the main reasons for the success of hydrate formation at the CO2-limited ratio only in the porous medium. Lastly, three steps during hydrate dissociation via thermal stimulation, such as heat transfer driving, kinetic driving, and fluid flow driving, are no longer discernable in the porous medium due to the limited heat and mass transfer during the process.

Negative emission technologies such as biomass with carbon capture and storage (bioCCS) may become an important instrument to limit global warming. Currently, estimates of CO2 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 CO2(eq) and the net CO2(eq) from -660 to 16 kg CO2(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 CO2(eq) for near-term estimates and to 89-107€2017/t CO2(eq) for longer-term estimates.

Due to the degradation reaction and the presence of acidic impurities (HCl, SO2, etc.) in the flue gas, heat stable salts (HSS) are widely present in the aqueous amine solvent for post-combustion CO2 capture. Accumulation of HSS in the solvent can lead to decreased absorption capacity and even corrosion of equipment in post-combustion capture (PCC) pilot plants. This study presents a novel “BMED+ED” two-stage electrodialysis unit for the efficient removal of HSS, including glycolate, formate, Cl−, and SO42−, from degraded amine solvent with an initial loading of approximately 0.38 mol/mol taken from the solvent loop of a PCC pilot plant after over 1000 hours of operation at real conditions. Experimental results showed that 94.93% of HSSs were removed with an initial HSS concentration of approximately 1920 ppm. The amine loss rate in the two-stage electrodialysis unit was much lower than that in a conventional ED unit, as protonated amine is further converted to organic amines by bipolar membrane electrodialysis. The energy consumption of the two-stage electrodialysis unit was 0.1643 kWh/L amine solvent, and the total cost for amine reclaiming was 1.8145 $/kg amine. This method effectively addressed the challenges of high amine loss rate in the traditional ED treatment process and hazardous wastewater disposal.

A combined rich and lean vapour compression configuration was investigated for CO2 capture from a cement plant. This was to assess its performance in energy consumption, actual CO2 emission reduction, and cost reduction potentials compared with the conventional process and the simple rich vapour compression and lean vapour compression configurations. Two electricity supply scenarios were considered: from natural gas combined cycle power plant and a renewable source like hydropower. The three vapour compression configurations outperformed the standard CO2 absorption configuration in energy requirement, actual CO2 emissions reduction and in CO2 avoided cost reduction. The best performance was achieved by the combined rich and lean vapour compression configuration. The reboiler heat, equivalent heat and CO2 avoided cost reduction performance was 24 – 30 %, 16 -18 % and 13 – 16 % respectively. However, the performances in energy, CO2 emissions reduction and CO2 avoided cost are only marginally better than the lean vapour compression configuration. The use of renewable electricity, like hydropower electricity will help CO2 capture processes to achieve higher CO2 emission reduction and lower CO2 avoided cost compared to fossil fuel based electricity.

Depleted hydrocarbon reservoirs are a promising target for CO2 sequestration. Injection of cold CO2 into such geological reservoirs will cause thermal stresses and strains in wellbore casings, cement seals and surrounding rock, which may lead to the creation of unwanted pathways for seepage. Joule-Thomson effects could potentially produce freezing conditions. The design of CO2 injector wells must be able to cope with these thermal loads. While numerical modelling can be used to develop our understanding and assess the impact of thermal processes on wellbore integrity, such analyses require reliable input data for material properties, such as those of the cement seals. This critical review provides an overview of existing lab measurements and theoretical considerations to help constrain the thermal behaviour of Portland cement under relevant subsurface conditions. Special attention is given to the i) thermal conductivity, ii) specific heat capacity, and iii) coefficient of thermal expansion. Influences on these properties of factors such as a) temperature, b) pressure, c) mixing water-to-cement ratio, d) extent of hydration, e) porosity, and f) pore fluid saturation are discussed. Our review has shown that lab datasets obtained under relevant downhole conditions are limited, constraining the input for numerical assessment of wellbore cement integrity.

Carbon capture and storage (CCS) projects rely on numerical reservoir simulations for determining where and how much CO2 can safely be stored underground. Conventional simulations are computationally expensive and time consuming, thereby increasing the turn-around time of decision-making processes and projects. Recent research on artificial intelligence (AI) based approaches for solving the underlying two-phase flow equations has shown enormous promise, as the computational burden can be shifted to the training time, while simulations can be performed in fractions of a second at test time. Applications of AI methods for simulating CO2 flow and other differential equations have so far been limited to 2D or small 3D problems with relatively simple geometries. We introduce a cloud-native framework for parallel simulations of large-scale training data sets using the Open Porous Media (OPM) simulator and we propose a new AI architecture based on Fourier Neural Operators (FNOs) with 3D wavelet transforms. This architecture performs better than FNOs on data with shock fronts, such as simulating CO2 saturation. We also provide a new training dataset for CO2 flow based on the Sleipner CO2 storage geomodel from the Norwegian continental shelf and show that both FNOs and Wavelet Neural Operators (WNOs) can be trained on models with over 200,000 cells and lead to significant speed-ups of up to 50,000× (FNOs) and 100× (Wavelet NOs) over numerical simulations of CO2 saturation with OPM.

Using lignocellulosic biomass-based sorbents for CO2 capture potentially offers a sustainable solution to combatting global warming effects and preserving the environment through reduction of greenhouse gas emissions, mainly carbon dioxide. In this work, activated carbons were produced from microcrystalline cellulose using a simple, moderate physical activation procedure. Activations produced at 10, 20 and 30% burn-off along with the original biochar were characterised for their physical and chemical properties, and ability to capture CO2 by adsorption. CO2 isotherms showed that the produced activated carbon with a burn-off of 30 wt% produced the highest CO2 adsorption capacity (2.15 mmol/g at 25°C and 101.3 kPa). Isosteric heats of adsorption of all sorbents ranged from 38.4 to 45.2 kJ/mol, which indicates that strong bonding is present on the surface of the developed sorbents. The highest CO2 adsorption capacity (1.59 mmol/g at 25°C and 101.3 kPa) under dynamic adsorption conditions at was also exhibited by the sorbent with 30 wt% burn-off. This sample also showed a total CO2 adsorption capacity of 15.8 mmol/g over 10 adsorption/desorption cycles and similar adsorption-desorption behaviour to that of commercial sorbent Norit R2030CO2 over 10 cycles, at the conditions tested. Additionally, all sorbents maintained a stable CO2 capture capacity over 10 adsorption-desorption cycles. The results obtained are encouraging for the further development of microcrystalline cellulose-based activated carbons for CO2 capture.

The importance of CO2 storage in deep geological formations to mitigate CO2 emissions, has triggered the investigation of possible sites worldwide. This study presents a hierarchical basin-wide evaluation of the Tampico-Misantla basin (TMB), Mexico, following a basin evaluation methodology based on literature criteria and local particularities. The results show that the TMB has significant potential to adequately store CO2. The stratigraphy evaluation reveals two candidate aquifers: (1) the Cretaceous Tamaulipas and (2) the Jurassic Cahuasas formations. Twenty-three criteria are taken into account to evaluate the storage potential of the area. A numerical scoring and weighting scheme integrate all the criteria in a raster, thus allowing the storage potential to be depicted using a normalized scale. The prospective areas are restricted by the 0.8 isoline normalized value (over 1). Considering the aquifer's volume with potential above 0.8, the effective storage capacity of the basin is estimated to be 972.3 to 1346.0 million tonnes of CO2.

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 CO2 storage capacity are examined, summarizing all study results gathered under the Strategy CCUS project. The CO2 enhanced oil recovery is being studied for CO2 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 CO2 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 CO2 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.

The naturally occurring bio-geochemical microbial-induced calcium carbonate precipitation (MICP) process is an eco-friendly technology for rehabilitating construction materials, reinforcement of soils and sand, heavy metals immobilization and sealing subsurface leakage pathways. We report pore-scale spatiotemporal dynamics of the MICP process in porous media, relevant for reduced environmental risk by leakage during CO2 geological storage. Effects of hydrodynamics and supersaturation on the MICP with Sporosarcina pasteurii stains were studied using a high-pressure, rock-on-a-chip microfluidic device. Bacterial cell numbers and variation in cementation concentration controlled the crystal size and pore-scale distribution by influencing the local supersaturation. Local pore structure determined crystal nucleation, where low velocity regions tended to nucleate more crystals. CaCO3 crystallization was observed at subsurface pressure (100 barg) with a reduced sealing performance due to the low microbial activity from elevated pressure. We identify that hydrodynamics and supersaturation determine crystal nucleation and growth in porous systems, providing important experimental evidence for subsurface environmental applications and validation of upscaled MICP models.

Among the pollutants known as greenhouse gasses, carbon dioxide (CO2), although it is less toxic than the others, has by far the most significant amount of pollution in the earth's atmosphere. Also, it is one of the typical components of natural gas, which is removed due to the increase in fuel value and the adjustment of pipeline standards to prevent acid corrosion. There are various techniques for CO2 removal, among which membrane processes are a new and applied technology with many advantages in industrial separation. 3-diethylaminopropylamine (DEAPA) is a new amine absorbent with good interaction with CO2 molecules and increased absorption capacity, which shows good potential for CO2 separation. This study aims to investigate the performance potential of CO2 absorption by an aqueous solution of DEAPA as an absorbent in a hollow fiber membrane contactor (HFMC) with hydrophobic porous polytetrafluoroethylene (PTFE) fibers. A two-dimensional mathematical model was presented and solved based on the finite element method (FEM) to evaluate the CO2 removal efficiency. The effect of different parameters such as amine concentration, liquid and gas flow rate, liquid temperature, CO2 partial pressure, membrane tortuosity, number of hollow fibers, and packing density on CO2 absorption performance was investigated. The model results showed that increasing the gas flow rate and membrane tortuosity has a negative effect on CO2 removal. Also, increasing the amine concentration, packing density, the number of hollow fibers, DEAPA concentration, liquid temperature, and CO2 partial pressure improve the CO2 separation efficiency.