Density Of Carbon Dioxide Research Articles

Optimization of drug solubility inside the supercritical CO2 system via numerical simulation based on artificial intelligence approach

In this research paper, we explored the predictive capabilities of three different models of Polynomial Regression (PR), Extreme Gradient Boosting (XGB), and LASSO to estimate the density of supercritical carbon dioxide (SC-CO2) and the solubility of niflumic acid as functions of the input variables of temperature and pressure. The optimization of hyperparameters for these models is achieved using the innovative Barnacles Mating Optimizer (BMO) algorithm. For SC-CO2 density estimation, PR exhibits remarkable accuracy, showing an R-squared value of 0.99207 for data fitting. XGB performs admirably with an R2 of 0.92673, while LASSO model demonstrates good predictive ability, showing an R2 of 0.81917. Furthermore, we assess the models’ performance in predicting the solubility of niflumic acid. PR exhibits excellent predictive capabilities with an R2 of 0.96949. XGB also delivers strong performance, yielding an R-squared score of 0.92961. LASSO performs well, achieving an R-squared score of 0.82094. The results indicated promising performance of machine learning models and optimizer in estimating drug solubility in supercritical CO2 as the solvent applicable for pharmaceutical industry.

Artificial intelligence for computation and development of nanodrug solubility in supercritical solvent: Analysis of temperature and pressure influence

This paper presents an investigation into the modeling and prediction of the density of supercritical carbon dioxide (SC-CO2) and mole fraction of Erlotinib hydrochloride using machine learning techniques. The dataset consists of temperature and pressure as input variables, with density of SC-CO2 and mole fraction of Erlotinib hydrochloride as output variables. The process is supercritical-based operation which can be used for production of nanomedicines with improved aqueous solubility. Three models, Multilayer Perceptron (MLP), Orthogonal Matching Pursuit (OMP), and Extreme Gradient Boosting (XGB) were trained and optimized using the Firefly Optimization Algorithm (FA). The models’ performance in correlating solubility and density were evaluated via statistical analyses to measure their accuracy. The MLP model achieved high accuracy, with scores of 0.99714 and 0.97749 for density and mole fraction prediction, respectively in term of coefficient of determination (R2). The OMP and XGB models also provided reasonably accurate results. These findings demonstrate the effectiveness of machine learning in understanding and predicting SC-CO2 behavior, with potential applications in industrial processes and pharmaceutical formulations.

The retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide: Measurements and correlation

The retention factors and infinite dilution partial molar volumes of a solute in supercritical fluid are crucial for understanding solute–solvent interactions, analyzing pressure effects on chemical reactions, and optimizing industrial processes. Despite their importance, there is a notable scarcity of available data on retention factors and infinite dilution partial molar volumes in supercritical fluid systems. This study presents the first experimental data on the retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide. The retention factors were measured across temperatures ranging from 308.15 to 353.15 K and pressures of 8.20 to 31.03 MPa using supercritical fluid chromatography. The infinite dilution partial molar volumes were determined by taking the partial derivative of the retention factors with respect to the density of carbon dioxide. The obtained infinite dilution partial molar volumes range from −1.64 × 10−2 to 4.10 × 10−4 m3/mol, with large negative values observed near the critical point of carbon dioxide, indicating strong solvent–solute interactions. In this study, a new correlation model successfully predicts the experimental infinite dilution partial molar volumes with an average absolute relative deviation of 2.3 % over 86 data points.

Effects of the 2007 Martian Global Dust Storm on Boundary Positions in the Induced Magnetosphere

Mars's magnetosphere is a sensitive system, varying due to external and internal factors, such as solar wind conditions and crustal magnetic fields. A signature of this influence can be seen in the position of two boundaries; the bow shock and the induced magnetospheric boundary (IMB). The bow shock moves closer to Mars during times of high solar activity, and both the bow shock and IMB bulge away from Mars over crustal magnetic fields in the southern hemisphere. This study investigates whether large-scale atmospheric events at Mars have any signature in these two magnetic boundaries, by investigating the 2007 storm. The 2007 global storm lasted for several months and increased atmospheric temperatures and densities of both water vapor and carbon dioxide in the atmosphere, leading to an increase in atmospheric escape. Using Mars Express, we identified boundary locations before, during, and after the event, and compared these to modeled boundary locations and areographical locations on Mars. We find that, while it is unclear whether the bow shock position is impacted by the storm, the IMB location does change significantly, despite the orbital bias introduced by Mars Express. The terminator distance for the IMB peaks at longitudes 0°–40° and 310°–360°, leaving a depression around 180° longitude, where the boundary usually extends to higher altitudes due to the crustal magnetic fields. We suggest this may be due to the confinement of ionospheric plasma over crustal fields preventing mixing with the dust, creating a dip in ionospheric pressure here.

Elucidating supercritical fluid extraction of fucoxanthin from algae to enable the integrated biorefinery

The emerging nutraceutical, fucoxanthin, shows promise as a high-value product to enable the integrated biorefinery. Fucoxanthin can be extracted from algae through supercritical fluid extraction (SFE), but literature does not agree on optimal extraction conditions. Here, a statistical analysis of literature identifies supercritical carbon dioxide (scCO2) density, ethanol cosolvent amount, and polarity as significant predictors of fucoxanthin yield. Novel SFE experiments are then performed using a fucoxanthin standard, describing its fundamental solubility. These experiments establish solvent system polarity as the key knob to tune fucoxanthin recovery from 0% to 100% and give specific operating conditions for targeted fucoxanthin extraction.Further experiments compare extractions on fucoxanthin standard with extractions from Phaeodactylum tricornutum microalgae to elucidate the effect of the algae matrix. Results show selectivity of fucoxanthin over chlorophyll in scCO2 microalgae extractions that was not seen in extractions with ethanol, indicating a benefit of scCO2 to design selective extraction schemes.

Experimental Study on Carbon Dioxide Flooding Technology in the Lunnan Oilfield, Tarim Basin

The Lunnan Oilfield in the Tarim Basin is known for its abundant oil and gas resources. However, the marine clastic reservoir in this oilfield poses challenges due to its tightness and difficulty in development using conventional water drive methods. To improve the recovery rate, this study focuses on the application of carbon dioxide flooding after a water drive. Indoor experiments were conducted on the formation fluids of the Lunnan Oil Formation, specifically investigating gas injection expansion, thin tube, long core displacement, oil and gas phase permeability, and solubility. By injecting carbon dioxide under the current formation pressure, the study explores the impact of varying amounts of carbon dioxide on crude oil extraction capacity, high-pressure physical parameters of crude oil, and phase characteristics of formation fluids. Additionally, the maximum dissolution capacity of carbon dioxide in formation water is analyzed under different formation temperatures and pressures. The research findings indicate that the crude oil extracted from the Lunnan Oilfield exhibits specific characteristics such as low viscosity, low freezing point, low-medium sulfur content, high wax content, and medium colloid asphaltene. The measured density of carbon dioxide under the conditions of the oil group is 0.74 g/cm3, which closely matches the density of crude oil. Additionally, the viscosity of carbon dioxide is 0.0681 mPa·s, making it well-suited for carbon dioxide flooding. With an increase in the amount of injected carbon dioxide, the saturation pressure and gas-oil ratio of the crude oil also increase. As the pressure rises, carbon dioxide dissolves rapidly into the crude oil, resulting in a gradual increase in the gas-oil ratio, expansion coefficient, and saturation pressure. As the displacement pressure decreases, the degree of carbon dioxide displacement initially decreases slowly, followed by a rapid decrease. Moreover, an increase in the injection rate of carbon dioxide pore volume leads to a rapid initial improvement in oil-displacement efficiency, followed by a slower increase. Simultaneously, the gas-oil ratio exhibits a slow increase initially, followed by a rapid rise. Furthermore, as the displacement pressure increases, the solubility of carbon dioxide in water demonstrates a linear increase. These research findings provide valuable theoretical data to support the use of carbon dioxide flooding techniques for enhancing oil recovery.

Data-driven models and comparison for correlation of pharmaceutical solubility in supercritical solvent based on pressure and temperature as inputs

Data-driven models were employed for the solubility correlation, while the focus was on modeling the solubility of raloxifene drug and density of carbon dioxide based on temperature (T) and pressure (P) inputs. Three Machine Learning models, namely Multilayer Perceptron (MLP), Bayesian Ridge Regression (BRR), and LASSO regression, were employed and optimized using the MPHPT method for hyper-parameter tuning. The dataset consisted of experimental measurements of solubility (y), and CO2 density. For the prediction of density, the MLP model exhibited excellent performance with an R2 score of 0.99726, demonstrating a significant level of association between the anticipated and observed values. The mean squared error (MSE) was 9.8721E+01, the mean absolute percentage error (MAPE) was 1.78565E-02, and the maximum error was 1.86395E+01. The LASSO and BRR models achieved slightly lower accuracy, with R2 scores of 0.83317 and 0.83001, respectively. Regarding the solubility of the raloxifene drug, the MLP model demonstrated a strong predictive capability with an R2 score of 0.99343. The MSE was 3.0869E-02, MAPE was 4.02666E-02, and the maximum error was 3.01133E-01. The LASSO and BRR models also provided reasonable predictions, with R2 scores of 0.90955 and 0.8891, respectively. However, they exhibited higher MSEs and MAPEs compared to the MLP model.

Quartz-Hosted Fluid Inclusions in Commercial Ores of Various Type at the Verninskoe Gold Deposit, Bodaibo District, Russia

The paper presents data on quartz-hosted fluid inclusions in commercial ores of various type (veinlet−disseminated and vein) of the Verninskoe gold deposit. The ores of various types were found out to significantly vary in the values of some of their physicochemical parameters of the fluids and in the composition of these fluids. The fluids that formed the gold veins have a somewhat higher initial temperature (356–246°C), a higher density of carbon dioxide in gas inclusions (1.00–0.84 g/cm3), and a higher fluid pressure (3170–1390 bar) than those of the fluids that formed the veinlet–disseminated ores (330–252°C, 0.87–0.54 g/cm3, and 1960–570 bar, respectively). The fluids that formed the gold veins were enriched in CО2, Sr, Ag, Ga, Ge, Mn, Fe, Ni, Sn, Ba, and REE, whereas the fluids that formed veinlet–disseminated mineralization were richer in HCO−3, Br, Sb, V, and Au. This situations may be explained by the interaction of the deep fluid with the terrigenous host rocks in the course of ore deposition. When vein quartz crystallized in relatively wide fractures, the fluid interacted with host rocks and changed not as much as when the veinlet−disseminated ores were formed in narrow fractures. The initial parameters of the fluid that formed the vein quartz were thus the closest to the characteristics of the fluid that transported the ore components, and the comparison of these data with the parameters of the fluids that formed the veinlet–disseminated mineralization demonstrates that they changed in the course of ore deposition. The mineral-forming fluids likely came from a deep-sitting source, and the mineral-forming processes may have involve granitoid-derived fluids.

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profiles Retrievals With the Hydrostatic Equilibrium Equation: 1. Description of the Method

AbstractThe Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument has been scanning the Martian atmosphere for almost 2 Martian years. In this work, we present a subset of the NOMAD SO data measured at the mesosphere at the terminator. From the data set, we investigated 968 vertical profiles of carbon dioxide density and temperature covering the Martian Year (MY) 35 as well as MY 36 up to a solar longitude (Ls) of 135° and altitudes around 60–100 km. While carbon dioxide density profiles are directly retrieved from the spectral signature in the spectra, temperature profiles are more challenging to retrieve as unlike density profiles, temperature profiles can present some spurious features if the regularization is not correctly managed. Comparing seven regularization methods, we found that the expected error estimation method provides the best regularization parameters. The vertical resolution of the profiles is on average 1.6 km. Numerous warm layers and cold pockets appear in this data set. The warm layers are found in the Northern hemisphere at dawn and dusk as well as in the Southern hemisphere at dawn. Strong warm layers are present in more than 13.5% of the profiles. The Southern hemisphere at dusk does not present any warm layer between Ls 50° and 150°. The height and latitudinal distribution of those warm layers were similar in MY 35 and MY 36 during the first half of the year (Ls = 0°–135°).

Carbon Dioxide Retrievals From NOMAD‐SO on ESA's ExoMars Trace Gas Orbiter and Temperature Profile Retrievals With the Hydrostatic Equilibrium Equation: 2. Temperature Variabilities in the Mesosphere at Mars Terminator

AbstractThe Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument scans the Martian atmosphere since 21 April 2018. In this work, we present a subset of the NOMAD SO data measured at the mesosphere. We focused on a spectral range that started to be recorded in Martian year (MY) 35. A total of 968 vertical profiles of carbon dioxide density and temperature covering MY 35 and the beginning of MY 36 were investigated until 135° of solar longitude. We compared 47 profiles with co‐located profiles of the Mars Climate Sounder onboard the Mars Reconnaissance Orbiter. Most profiles show a good agreement as SO temperatures are only 1.8 K higher, but some biases lead to an average absolute difference of 7.4°K. The SO data set is also compared with simulations from the Global Environmental Multiscale‐Mars general circulation model. Both data sets are in good agreement except for the presence of a cold layer in the winter hemisphere and a warm layer at dawn in the Northern hemisphere for solar longitudes between 240° and 360°. Five profiles contain temperatures lower than the limit for CO2 condensation. Strong warm layers were found in 13.5% of the profiles. They are present mainly at dawn and in the winter hemisphere, while the Northern dusks appear featureless. The data set mainly covers high latitudes around 60° and we derived some non‐migrating tides. In the Southern winter hemisphere, we derived apparent zonal wavenumber‐1 (WN‐1) and WN‐3 tidal components with a maximum amplitude of 10% and 5% at 63 km, respectively.

Density and Viscosity Measurements of n-Dodecane and Carbon Dioxide + n-Dodecane at Temperatures from (298 to 548) K

Density and Viscosity Measurements of n-Dodecane and Carbon Dioxide + n-Dodecane at Temperatures from (298 to 548) K

Thermal Structure of the Middle and Upper Atmosphere of Mars From ACS/TGO CO2Spectroscopy

AbstractTemperature and density in the upper Martian atmosphere, above ∼100 km, are key diagnostic parameters to study processes of the species' escape, investigate the impact of solar activity, model the atmospheric circulation, and plan spacecraft descent or aerobraking maneuvers. In this paper, we report vertical profiling of carbon dioxide (CO2) density and temperature from the Atmospheric Chemistry Suite (ACS) solar occultations onboard the ExoMars Trace Gas Orbiter. A strong CO2absorption band near 2.7 μm observed by the middle infrared spectrometric channel (ACS MIR) allows the retrieval of the atmospheric thermal structure in an unprecedentedly large altitude range, from 20 to 180 km. We present the latitudinal and seasonal climatology of the thermal structure for 1.5 Martian years (MYs), from the middle of MY 34 to the end of MY 35. The results show the variability of distinct atmospheric layers, such as a mesopause (derived from 70 to 145 km) and homopause, changing from 90 to 100 km at aphelion to 120–130 km at perihelion. Some short‐term homopause fluctuations are also observed depending on the dust activity.

Developing an accurate empirical correlation for predicting anti-cancer drugs’ dissolution in supercritical carbon dioxide

This study introduces a universal correlation based on the modified version of the Arrhenius equation to estimate the solubility of anti-cancer drugs in supercritical carbon dioxide (CO2). A combination of an Arrhenius-shape term and a departure function was proposed to estimate the solubility of anti-cancer drugs in supercritical CO2. This modified Arrhenius correlation predicts the solubility of anti-cancer drugs in supercritical CO2 from pressure, temperature, and carbon dioxide density. The pre-exponential of the Arrhenius linearly relates to the temperature and carbon dioxide density, and its exponential term is an inverse function of pressure. Moreover, the departure function linearly correlates with the natural logarithm of the ratio of carbon dioxide density to the temperature. The reliability of the proposed correlation is validated using all literature data for solubility of anti-cancer drugs in supercritical CO2. Furthermore, the predictive performance of the modified Arrhenius correlation is compared with ten available empirical correlations in the literature. Our developed correlation presents the absolute average relative deviation (AARD) of 9.54% for predicting 316 experimental measurements. On the other hand, the most accurate correlation in the literature presents the AARD = 14.90% over the same database. Indeed, 56.2% accuracy improvement in the solubility prediction of the anti-cancer drugs in supercritical CO2 is the primary outcome of the current study.

Examining partial-column density retrieval of lower-tropospheric CO2 from GOSAT target observations over global megacities

We retrieved and examined the partial-column densities of carbon dioxide (CO2) in the lower (LT, typically 0–4 km) and upper (UT, typically 4–12 km) troposphere (XCO2LT and XCO2UT) collected over six global megacities: Beijing, New Delhi, New York City, Riyadh, Shanghai, and Tokyo. The radiance spectra were collected using the Thermal And Near-infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT). Our retrieval method uniquely utilizes reflected sunlight with two orthogonal components of polarization and thermal emissions. We defined megacity concentration enhancement due to surface CO2 emissions as XCO2LT minus XCO2UT, allowing us to overcome some of the challenges in the enhancement analysis using existing column density data. We examined the relationship between the XCO2LT enhancements from the time series of intensive target observations over megacities and the inverse of simulated wind speed, which could be potentially used to estimate surface emissions. Next, we attempted to estimate the average emission intensity for each city from the linear regression slope. We also compared our obtained emission estimates with the Open-Data Inventory for Anthropogenic CO2 (ODIAC) inventory for evaluation. Our results demonstrate the potential utility of the new partial-column density retrievals for estimating megacity CO2 emissions. More frequent and comprehensive coverage characterizing the spatial distribution of emissions is necessary to reduce random error and bias associated with the obtained estimate.

Interfacial tension of ethanol, water, and their mixtures in high pressure carbon dioxide: Measurements and modeling

Hypothesis.It is particularly noteworthy to study interfacial tension behavior under pressurized carbon dioxide for supercritical processes such as crystallization or fractionation. For the latter, a liquid phase and a supercritical phase are in contact, and interfacial properties influence mass transfer phenomena and hydrodynamics. Ethanol-water mixture is a good theoretical study case also involved in a wide range of applications. ExperimentalInterfacial tensions of ethanol, water and three mixtures, with an ethanol mass fraction from 0.25 to 0.75, under pressurized CO2 were measured for pressures ranging from 0.1 MPa to 15.1 MPa at 313.15 K and 333.15 K. A specific experimental set-up was used for CO2 phase saturation. FindingsThis work brings interfacial tension data of five different solutions including water and ethanol in contact with CO2. Effects of pressure, temperature, carbon dioxide density and ethanol mass fraction are discussed regarding the literature. Significant discrepancies are found with previous literature data for ethanol–water mixtures. The “two-step” decrease observed when pressure or density increase is also discussed regarding both the concept of Widom line, and the polar and dispersive contributions of the surface tension of a component. For the first time, fair accurate interfacial tension modeling involving these contributions is addressed.

The effect of carbon dioxide gas pressure on solubility, density and pH of carbon dioxide – Water mixtures

Absorption process is the most used separation technology for CO 2 removal. The aim of this research is to investigate the effect of different carbon dioxide gas pressure towards solubility, density and pH of CO 2(g) + H 2 O (l) mixtures. The absorption process was investigated in a semi-batch reactor equipped with arduino monitoring system. The results indicated that the solubility and density of CO 2 in water increased with increasing of CO 2 gas pressure. The highest solubility of CO 2 in water was 1.320 gr/L. On the other hand, the pH values of CO 2 in water decreased with increasing of CO 2 gas pressure.

Laboratory simulation and dynamics study of carbon dioxide geological storage system

In recent years, the issue of carbon dioxide disposal has become a national hot issue, and China has pledged to the international community to achieve the goal of carbon neutrality by 2060. In this paper, the relationship between the water-rock reaction rate of different ores and temperature and alkalinity is first studied by consulting relevant data. It is found that the reaction rate of quartz increases with the increase of temperature under neutral conditions, and the reaction rate of manganese-free ore increases with the alkalinity. At the same time, the kinetic parameters of the water-rock reaction were determined. Secondly, the underground storage model of carbon dioxide is established by using the law of conservation of mass and Darcy's law, and a case of solving the model is given. Finally, the sensitivity analysis of the model was carried out, and it was found that the model was not sensitive to carbon dioxide density and flow, but was more sensitive to soil porosity, and the sensitivity first decreased, then increased and finally stabilized.

Experimental data and modeling for density and viscosity of carbon dioxide (CO2)-loaded and -unloaded aqueous blend of 2-(ethylamino)ethanol (EAE) and aminoethylethanolamine (AEEA) for post-combustion CO2 capture

Amine based chemical absorption is the most developed technique for post-combustion CO2 capture from flue gases of low CO2 partial pressure. Density and viscosity data of CO2 – loaded and –unloaded absorbent are important in kinetics study and design the absorption column. Density and viscosity of CO2 loaded and –unloaded aqueous blend of 2-(ethylamino)ethanol (EAE) + aminoethylethanolamine (AEEA) were obtained experimentally in the temperature range of 293.15 to 323.15 K with 5 K temperature interval at atmospheric pressure. Concentration of aqueous EAE + AEEA blend was 10 wt%, 20 wt%, and 30 wt% with 7/3 weight ratio of EAE/AEEA. Excess volume was calculated by using experimental density data and correlated with Redlich-Kister type equation. Correlations were developed to calculate density and viscosity. For CO2-loaded and –unloaded aqueous EAE + AEEA blend, correlations predicted data were with average absolute deviation percentage (AAD %) of 0.1286, 0.0208, respectively for density while with AAD % 4.744, 4.433, respectively for viscosity. Wieland model was also correlated to CO2-loaded viscosity data and AAD % was 2.852 for this model. Moreover, diffusivity of CO2 into the aqueous EAE + AEEA blend was calculated using modified Stokes-Einstein equation.

Response of atmospheric carbon dioxide to the secular variation of weakening geomagnetic field in whole atmosphere simulations

Responses of atmospheric carbon dioxide (CO₂) density to geomagnetic secular variation are investigated using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X). Our ensemble simulations show that CO₂ volume mixing ratios (VMRs) increase at high latitudes and decrease at mid and low latitudes by several ppmv in response to a 50% weakening of the geomagnetic field. Statistically significant changes in CO₂ are mainly found above ~90 km altitude and primarily redetermine the energy budget at ~100–110 km. Our analysis of transformed Eulerian mean (TEM) circulation found that CO₂ change is caused by enhanced upwelling at high latitudes and downwelling at mid and low latitudes as a result of increased Joule heating. We further analyzed the atmospheric CO₂ response to realistic geomagnetic weakening between 1978 and 2013, and found increasing (decreasing) CO₂ VMRs at high latitudes (mid and low latitudes) accordingly. For the first time, our simulation results demonstrate that the impact of geomagnetic variation on atmospheric CO₂ distribution is noticeable on a time scale of decades.

Spectroscopic Detection of Critical Compression of Carbon Dioxide Confined in an Nanoporous Aerogel by Coherent Anti-Stokes Raman Spectroscopy

The compaction of carbon dioxide in the pores of nanoporous silicon aerogel at near-critical temperatures has been studied by coherent anti-Stokes light scattering (CARS) spectroscopy. The density was determined by the shift of the vibrational line at 1388 cm $${}^{-1}$$ under isochoric heating from the subcritical temperature of 25.2 $${}^{\circ}$$ C to the supercritical one of 31.95 $${}^{\circ}$$ C. It was found that the density of carbon dioxide in nanopores near the critical temperature increases, exceeding the average value in the cuvette by about $${\sim}20\%$$ .