Dissolution Of Carbon Dioxide Research Articles

Effects of the hydrologic process and geochemistry on dissolved carbon in shallow groundwater surrounding Qinghai Lake

A high concentration of dissolved carbon in groundwater increases drinking water health risks and carbon transport. Understanding the comprehensive impact of hydrologic processes and geochemistry on dissolved carbon in shallow groundwater also is a fundamental prerequisite for estimating the carbon budget of lakes in the Tibetan Plateau. This study investigated the spatial–temporal characteristics of the hydrologic process, geochemistry and dissolved carbon in shallow groundwater by the stable isotope tracer method, Piper diagram and Boomerang envelope model. The driving factors of dissolved carbon in shallow groundwater were explored by correlation analysis and redundancy analysis. The results showed low dissolved inorganic carbon (DIC) concentrations and high dissolved organic carbon (DOC) concentrations during the thawing period and rainy season and high DIC concentrations and low DOC concentrations during the freezing period. The seepage velocity, soil carbon dioxide dissolution and gypsum dissolution were the main factors influencing DIC concentrations during the thawing period. The mineralization and decomposition of DOC and dissolution of carbonate rocks were the main factors influencing DIC concentrations during the freezing period. The concentrations of DOC were mainly controlled by the adsorption of Ca2+ and Mg2+, microbial activity and pollutants produced by human activities. Our results are useful for ecological sustainable development, human health, and research on the carbon transport in groundwater in the Tibetan Plateau.

Biomass productivity and characterization of Tetradesmus obliquus grown in a hybrid photobioreactor.

In this study, the effects of CO2 addition on the growth performance and biochemical composition of the green microalga Tetradesmus obliquus cultured in a hybrid algal production system (HAPS) were investigated. The HAPS combines the characteristics of tubular photobioreactors (towards a better carbon dioxide dissolution coefficient) with thin-layer cascade system (with a higher surface-to-volume ratio). Experimental batches were conducted with and without CO2 addition, and evaluated in terms of productivity and biomass characteristics (elemental composition, protein and lipid contents, pigments and fatty acids profiles). CO2 enrichment positively influenced productivity, and proteins, lipids, pigments and unsaturated fatty acids contents in biomass. The HAPS herein presented contributes to the optimization of microalgae cultures in open systems, since it allows, with a simple adaptation-a transit of the cultivation through a tubular portion where injection and dissolution of CO2 is efficient-to obtain in TLC systems, greater productivity and better-quality biomass.

The effect of gas solubility on the selection of cushion gas for underground hydrogen storage in aquifers

Underground hydrogen storage (UHS) is gaining worldwide attention as an efficient solution for energy supply-demand imbalance. However, deploying UHS at full scale encounters several challenges. One of the primary challenges is selecting a suitable cushion gas to optimize hydrogen storage and withdrawal efficiency. In the existing literature cushion gas dissolution in the resident reservoir fluid is not considered as one of the technical selection criteria and we aim to show in this paper that it is critically important as it affects hydrogen recovery, pressure maintenance and hydrogen purity. With a focus on hydrogen storage in aquifers, we investigated cushion gas solubility in water. Three potential cushion gases—carbon dioxide, methane, and nitrogen—were assessed through large-scale compositional simulations using a conceptual aquifer model, considering temperature and pressure conditions corresponding to the reservoir depth. Gas solubility analysis involved examining changes in reservoir pressure, water production, injected cushion gas volume, and gas saturation changes during the cyclic process. Two distinct scenarios, with and without gas solubility, were considered to understand the effect of solubility on produced hydrogen purity and efficiency. Results indicate that increasing cushion gas solubility decreases final hydrogen recovery. For the case of carbon dioxide, due to its high solubility in the reservoir water, hydrogen purity is reduced to 30 % and hydrogen recovery factor falls by 18 % compared to using methane and nitrogen. Despite this, carbon dioxide dissolution can favorably reduce cumulative water production and mitigate severe reservoir pressure drops during production. Therefore, the dissolution phenomenon should be a key consideration in the screening of cushion gases and subsequently in the design and operation of UHS. Understanding the relationship between cushion gas solubility and hydrogen production efficiency contributes to enhancing the overall performance, and the long-term success of UHS projects.

Parentage influence on gene expression under acidification revealed through single-embryo sequencing.

The dissolution of anthropogenic carbon dioxide (CO2 ) in seawater has altered its carbonate chemistry in the process of ocean acidification (OA). OA affects the viability of marine species. In particular, calcifying organisms and their early planktonic larval stages are considered vulnerable. These organisms often utilize energy reserves for metabolism rather than growth and calcification as supported by bulk RNA-sequencing (RNA-seq) experiments. Yet, transcriptomic profiling of a bulk sample reflects the average gene expression of the population, neglecting the variations between individuals, which forms the basis for natural selection. Here, we used single-embryo RNA-seq on larval sea urchin Heliocidaris crassispina, which is a commercially and ecologically valuable species in East Asia, to document gene expression changes to OA at an individual and family level. Three paternal half-sibs groups were fertilized and exposed to 3 pH conditions (ambient pH 8.0, 7.7 and 7.4) for 12 h prior to sequencing and oxygen consumption assay. The resulting transcriptomic profile of all embryos can be distinguished into four clusters, with differences in gene expressions that govern biomineralization, cell differentiation and patterning, as well as metabolism. While these responses were influenced by pH conditions, the male identities also had an effect. Specifically, a regression model and goodness of fit tests indicated a significant interaction between sire and pH on the probability of embryo membership in different clusters of gene expression. The single-embryo RNA-seq approach is promising in climate stressor research because not only does it highlight potential impacts before phenotypic changes were observed, but it also highlights variations between individuals and lineages, thus enabling a better determination of evolutionary potential.

Correction: Theoretical and experimental investigation regarding the impact of sodium dodecyl sulfate (SDS) on carbon dioxide dissolution

Correction: Theoretical and experimental investigation regarding the impact of sodium dodecyl sulfate (SDS) on carbon dioxide dissolution

Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO2–H2O Treatment

The dissolution of supercritical carbon dioxide (ScCO2) in water forms a ScCO2–H2O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO2-driven enhanced coalbed methane (CO2-ECBM) recovery process. Herein, the effect of ScCO2–H2O treatment on the physicochemical properties of coal was simulated in a high-pressure reactor. The migration of major elements, change in the pore structure, and change in the CH4 adsorption capacity of coal after the ScCO2–H2O treatment were detected using plasma emission spectroscopy, the low-temperature liquid nitrogen adsorption method, and the CH4 adsorption method, respectively. The results show that (1) the ScCO2–H2O treatment led to mineral reactions causing a significant migration of constant elements in the coal. The migration of Ca ions was the most significant, with an increase in their concentration in treated water from 0 to 16–970 mg·L−1, followed by Na, Mg, and K. Al migrated the least, from 0 to 0.004–2.555 mg·L−1. (2) The ScCO2–H2O treatment increased the pore volume and pore-specific surface area (SSA) of the coal via the dissolution and precipitation of minerals in the coal pores. The total pore volume increased from 0.000795–0.011543 to 0.001274–0.014644 cm3·g−1, and the total pore SSA increased from 0.084–3.332 to 0.400–6.061 m2·g−1. (3) Changes in the CH4 adsorption capacity were affected by the combined effects of a mineral reaction and pore structure change. The dissolved precipitates of the minerals in the coal pores after the ScCO2–H2O treatment caused elemental migration, which not only decreased the mineral content in the coal pores but also increased the total pore volume and total pore SSA, thus improving the CH4 adsorption capacity of the coal. This study provides theoretical support for CO2 sequestration and ECBM recovery.

High resolution electrochemical monitoring of small pH changes

Usually pH measurements are carried out using potentiometric technique. However, sensitivity of this method is low due to limitation set by Nernst equation – the moderate resolution is a significant problem in today demand for tracking small pH changes in various application areas.We propose a novel approach that allows electrochemical monitoring of pH changes with resolution reaching below 0.01 units in alkaline, acidic or close to neutral media. The proposed method uses all-solid state pH sensitive electrode with syringaldazine (Syr) modified multi-walled carbon nanotubes as the reference electrode modulating amperometric signal of Ag|AgCl electrode used as the working one. Due to high slope of the current vs. potential dependence for low-polarizable silver / silver chloride electrode relatively small changes of reference (pH-sensitive) electrode potential are transformed to pronounced changes of the recorded current. Ultimately, this results in significant increase in resolution of traced pH changes. Moreover, the current recorded is found to be linearly dependent on changes of H+ or OH− ions concentration in a broad pH range, which additionally contributes to increased resolution readout. Advantages of herein proposed approach were fully verified by monitoring minute changes of solution pH resulting from dissolution of carbon dioxide.

Diffusive and convective dissolution of carbon dioxide in a vertical cylindrical cell

Diffusive and convective dissolution of carbon dioxide in a vertical cylindrical cell

Theoretical and experimental investigation regarding the impact of sodium dodecyl sulfate (SDS) on carbon dioxide dissolution

Theoretical and experimental investigation regarding the impact of sodium dodecyl sulfate (SDS) on carbon dioxide dissolution

Effects of Reservoir Heterogeneity on CO2 Dissolution Efficiency in Randomly Multilayered Formations

Carbon dioxide (CO2) dissolution is the secondary trapping mechanism enhancing the long-term security of CO2 in confined geological formations. CO2 injected into a randomly multilayered formation will preferentially migrate along high permeability layers, increasing CO2 dissolution efficiency. In this study, sequential Gaussian simulation is adopted to construct the stratified saline formations, and two-phase flow based on MRST is established to illustrate the spatial mobility and distribution of CO2 migration. The results show that gravity index G and permeability heterogeneity σY2 are the two predominant factors controlling the spatial mobility and distribution of CO2 transports. The CO2 migration shows a totally different spatial mobility under different gravity index and heterogeneity. When the permeability discrepancy is relatively larger, CO2 preferentially migrates along the horizontal layer without accompanying the vertical migration. For the formation controlled by gravity index, CO2 migration is governed by supercritical gaseous characteristics. For the medium gravity index, the upward and lateral flow characteristics of the CO2 plume is determined by gravity index and heterogeneity. When the gravity index is smaller, permeability heterogeneity is the key factor influencing CO2 plume characteristics. Permeability heterogeneity is the decisive factor in determining final CO2 dissolution efficiency. This investigation of CO2 mobility in randomly multilayered reservoirs provides an effective reference for CO2 storage.

Solvent Dynamics Are Critical to Understanding Carbon Dioxide Dissolution and Hydration in Water.

Simulations of carbon dioxide (CO2) in water may aid in understanding the impact of its accumulation in aquatic environments and help advance technologies for carbon capture and utilization (via, e.g., mineralization). Quantum mechanical (QM) simulations based on static molecular models with polarizable continuum solvation poorly reproduce the energetics of CO2 hydration to form carbonic acid in water, independent of the level of QM theory employed. Only with density-functional-theory-based molecular dynamics and rare-event sampling, followed by energy corrections based on embedded correlated wavefunction theory (in conjunction with density functional embedding theory), can a close agreement between theory and experiment be achieved. Such multilevel simulations can serve as benchmarks for simpler, less costly models, giving insight into potential errors of the latter. The strong influence of sampling/averaging over dynamical solvent configurations on the energetics stems from the difference in polarity of both the transition state and product (both polar) versus the reactant (nonpolar). When a solute undergoes a change in polarity during reaction, affecting its interaction with the solvent, careful assessment of the energetic contribution of the solvent response to this change is critical. We show that static models (without structural sampling) that incorporate three explicit water molecules can yield far superior results than models with more explicit water molecules because fewer water molecules yield less configurational artifacts. Static models intelligently incorporating both explicit (molecules directly participating in the reaction) and implicit solvation, along with a proper QM theory, e.g., CCSD(T) for closed-shell systems, can close the accuracy gap between static and dynamic models.

Numerical Investigation of the Influence of Hydrodynamic Dispersion on Solutal Natural Convection

AbstractWe investigate numerically the effect of hydrodynamic dispersion on convective dissolution of carbon dioxide in saline aquifers. Solutions of the transport equations were used to describe the dissolution process in the aquifer and provide a systematic parametric analysis of the influence of dispersion on two important measures of convective dissolution, the wavenumber, and dissolution flux. The results suggest that dispersion decreases the dissolution rate and reduces the finger wavenumber. Based on the simulated results, new empirical scaling laws that predict the dissolution rate and wavenumber were developed. The application of the new laws to two storage sites shows that the currently available predictions overestimate the dissolution rates by ∼30%. We have identified some discrepancies between published scaling laws that were obtained for the dissolution rate. While most numerical studies identify a linear scaling, experimental investigations often suggest a sublinear behavior. Our findings resolve the controversy by suggesting that dispersion, which was not considered in these past numerical studies, is the reason for the apparent sublinear scaling.

Convective dissolution of carbon dioxide into brine in a three-dimensional free medium

Carbon dioxide (CO${}_{2}$) can be stored in huge quantities in deep saline reservoirs, thus providing a key contribution to the fight against global warming. A complete understanding of the convective dissolution process can help optimize CO${}_{2}$ storage. Observing in a different direction, i.e. parallel to gravity, highlights the 3-dimensional structure of convection dominated, at an early stage, by falling sheets. That allows an accurate measurement of the onset time of convection, verifying the predicted power-law master curve independent of the liquid phase composition. This demonstrates that adding salt simply shifts the thermodynamic state by to a different Rayleigh number.

Evaluation of immiscible CO2 injection in high water production reservoir in the Pannonian basin

Carbon dioxide (CO2) flooding is one of the most important and most used enhanced oil recovery (EOR) method because it does not only increase oil recovery efficiency but also is used as an underground CO2 storage. It is considered a very complex method as it involves knowing the fluid phase behavior with different CO2 concentrations. It should be noted that oil swelling (volume increase) with the dissolution of carbon dioxide has a significant effect on increase of oil recovery. When this occurs, a significant decrease in the viscosity of the oil is observed. In this study, a reservoir 3D simulation modeling approach was applied to evaluate immiscible and miscible CO2 flooding in a high WC reservoir. To reduce simulation time, the PVT composition was grouped into 5 fluid components. The 3-parameter, Peng-Robinson Equation of State (EOS) was used to match PVT experimental data by using the Schlumberger's ECLIPSE PVTi software. One-dimensional slim-tube model was defined using ECLIPSE 300 software to determine the minimum miscibility pressure (MMP) for injection of CO2. Beside this approach, an analytical MMP estimation was carried out using several correlations. Schlumberger Petrel software was used to set up a 3D simulation model of a static and dynamic model. Various scenarios of immiscible and CO2 injection have been simulated using ECLIPSE 300 software and these results have been compared.

Experimental characterization of the difference in induction period between CH4 and CO2 hydrates: Motivations and possible consequences on the replacement process

The present research explores the differences in induction time between methane and carbon dioxide hydrates. This parameter was calculated by considering the heat released during the formation of hydrates. Being the process exothermic, the heat released, in conjunction with the enthalpy of formation, allowed to calculate the quantity of hydrates formed as soon as the process became detectable. This information was then combined with the measure of time to define the induction period. The procedure was selected in order to avoid possible errors related to the dissolution of carbon dioxide in water, which may affect the accuracy of detection. It was found that the induction time is significantly longer for carbon dioxide hydrates. It can be explained with the non-hydrophobicity of the molecule and with the higher Gibbs free energy barrier which must be overcome to produce the first nuclei of CO2 hydrates. The reliability of the proposed method was verified by evaluating the gas absorption over time for methane, whose dissolution in water can be considered negligible. Finally, it was proved that, after the formation of the first conglomerates, the growth of carbon dioxide hydrates is faster than that of methane hydrates, due to the higher degree of mixing between water and gas molecules within the whole formation environment.

Enhanced oil recovery through synergy of the interfacial mechanisms by low salinity water alternating carbon dioxide injection

During this study, a comprehensive investigation of low salinity water alternating CO2 injection was performed for enhanced oil recovery in oil-wet carbonate reservoirs. A synergy of interfacial mechanisms such as IFT, wettability alteration, CO2 solubility, oil swelling, water shielding effect, and rock dissolution was considered in two and three-phase systems. Results showed that the monovalent ions, such as NaCl or KCl, inhibit the dissolution of carbon dioxide in brine in excess of divalent salt solutions, e.g. CaCl2 or MgCl2 due to the salting-out effect. In addition, more water shielding effect was observed in low salinity formation water than it in low salinity seawater. The significant change in the reservoir wettability of oil/brine/CO2 system compared to oil/brine referred to the CO2 solubility in brine which could cause stronger carbonated water in the reservoir. Consequently, the low salinity alternating CO2 injection overpowers the late-production problem that occurred commonly in conventional WAG injection.

Prediction method of solubility of carbon dioxide and methane during gas invasion in deep-water drilling

Gases that invade during deep-water oil and gas drilling may be concealed due to the gas dissolution effect, leading to increased well control risks. Accurate and rapid prediction of carbon dioxide and methane dissolution is of great significance for the prediction and control of wellbore pressure during gas invasion. In this study, 316 sets of carbon dioxide solubility data at 288.15 to 423.15 K and 0.1 to 100 MPa, and 266 sets of methane solubility data at 275.15 to 444.3 K and 0.1 to 68 MPa were used to train a machine learning algorithm. The machine learning prediction method for gas solubility was established with a support vector regression machine and a particle swarm optimisation algorithm. The kernel function and disciplinary parameters of the support vector regression machine were optimised using the experimental dataset. The solubility of CO2 and CH4 in water was measured using a gas solubility measurement device. The experimental and model analysis showed that the solubility of CO2 varied in different phase states. At a given pressure, the solubility of CO2 was highest in the liquid state, followed by the supercritical state, and then the gaseous state. The average absolute relative deviation percentages between the calculated values of the CO2 and CH4 solubility models and the experimental values were 2.57 and 8.20, respectively. The machine learning method is consistent with the high-precision Duan thermodynamic model for predicting the solubility of CO2 and CH4 in water and can be used to predict the gas solubility in deep water and deep oil and gas drilling.

ЭЛЕКТРОПРОВОДНОСТЬ ВОДНЫХ РАСТВОРОВ АЛАНИНА И ВАЛИНА, ПРИГОТОВЛЕННЫХ ИТЕРАЦИОННЫМ МЕТОДОМ РАЗБАВЛЕНИЯ С ПОСЛЕДУЮШИМ ИНТЕНСИВНЫМ МЕХАНИЧЕСКИМ ВОЗДЕЙСТВИЕМ

The method of preparation of highly diluted solutions, by iterative dilution accompanied by intense mechanical action is described. The results of high-frequency electrical conductivity and dielectric permittivity of L and D isomers of alanine and valine are presented. The absence of dielectric increment in all samples indicates the absence of mesoparticles with high dielectric permittivity in solutions. A non-monotonic, complex dependence of electrical conductivity on the number of N dilution iterations is recorded. This type of dependence persists at large N, when the concept of the solute concentration loses its meaning, which indicates changes in the composition of aqueous solutions under mechanical impact. Repeated measurements of samples stored in closed vials in closed cardboard boxes at room conditions revealed long-term evolutionary processes in aqueous solutions. The peculiarity of the evolution of the electrical conductivity of alanine and valine solutions, in comparison with the previously studied potentiated diclofenac solutions, consists in a decrease in electrical conductivity over time, which contradicts the additional dissolution of carbon dioxide from the atmosphere when opening vials and dissolving glass. There were no differences in the properties of L and D isomers of alanine and valine solutions.

Carbon Dioxide (CO2) Dissolution Efficiency During Geological Carbon Sequestration (GCS) in Randomly Stratified Formations

AbstractGeological carbon sequestration mitigates climate change by capturing and storing carbon dioxide (CO2) emissions in deep geologic formations. Dissolution trapping is one mechanism by which CO2 can be trapped in a deep formation. However, heterogeneity can significantly affect the dissolution efficiency. This work addresses the injection of CO2 in perfectly stratified saline formations under uncertainty. Monte Carlo two‐phase flow compositional simulations involving the dissolution of CO2 into brine and evaporation of water into the CO2‐rich phase are presented. We systematically analyzed the interplay between heterogeneity and gravity factor (G), which is shown to control the migration of the CO2 plume as well as the temporal evolution of dissolution efficiency. Results show that when G is important, vertical segregation controls the overall behavior of CO2, diminishing the influence of small‐scale heterogeneity on dissolution. However, when G is relatively small compared to , CO2 migrates preferentially through high permeability layers and dissolution efficiency increases with due to the stretching of the CO2 plume that enhances mixing. As a result, in this situation, the upscaling of permeability leads to an underestimation of the dissolution efficiency. A review of field sites shows that dissolution is heterogeneity‐controlled in most real systems. Knowing that most numerical models cannot afford to represent heterogeneity at an adequate scale, results indicate that dissolution efficiency can be typically underestimated by a factor close to 1.5.

Convective dissolution of carbon dioxide in two- and three-dimensional porous media: The impact of hydrodynamic dispersion

Convective dissolution is the process by which CO2 injected in geological formations dissolves into the aqueous phase and thus remains stored perennially by gravity. It can be modeled by buoyancy-coupled Darcy flow and solute transport. The transport equation should include a diffusive term accounting for hydrodynamic dispersion, wherein the effective diffusion coefficient is proportional to the local interstitial velocity. We investigate the impact of the hydrodynamic dispersion tensor on convective dissolution in two-dimensional (2D) and three-dimensional (3D) homogeneous porous media. Using a novel numerical model, we systematically analyze, among other observables, the time evolution of the fingers' structure, dissolution flux in the quasi-constant flux regime, and mean concentration of the dissolved CO2; we also determine the onset time of convection, ton. For a given Rayleigh number Ra, the efficiency of convective dissolution over long times is controlled by ton. For porous media with a dispersion anisotropy commonly found in the subsurface, ton increases as a function of the longitudinal dispersion's strength (S), in agreement with previous experimental findings and in contrast to previous numerical findings, a discrepancy that we explain. More generally, for a given strength of transverse dispersion, longitudinal dispersion always slows down convective dissolution, while for a given strength of longitudinal dispersion, transverse dispersion always accelerates it. Furthermore, a systematic comparison between 2D and 3D results shows that they are consistent on all accounts, except for a slight difference in ton and a significant impact of Ra on the dependence of the finger number density on S in 3D.