Interfacial Tension and Density of Ethanol in Contact with Carbon Dioxide

The mass transfer of carbon dioxide through the outer polyethylene casing of district heating pipes, at room temperature, was evaluated, using different test methods. The mass transfer either through polyethylene casings on polyurethane preinsulated district heating pipes or through polyethylene casings alone was mea sured. Permeability coefficients of different polyethylene casings were about 20 · 10-18 kg·m-1·s-1·Pa-1. Permeability coefficients for carbon dioxide in polyurethane foam is about 100 times lower, which means that the mass transfer resistance to car bon dioxide of the polyurethane foam in a district heating pipe is negligible in com parison with the polyethylene casing.

Effects of dissolved binary ionic compounds and different densities of brine on interfacial tension (IFT), wettability alteration, and contact angle in smart water and carbonated smart water injection processes in carbonate oil reservoirs

Intensified biogas purification in a stirred tank

Multiphase CO[formula omitted] dispersions in microfluidics: Formation, phases, and mass transfer

Effects of surfactant type and structure on properties of amines for carbon dioxide capture

Dissolved carbon dioxide and bicarbonate ions in fermentation broths can (independently) inhibit or promote microbial growth and productivity. In research facilities with a large number of fermenters, dissolved carbon dioxide sensors tend not to be used, and as a result this variable will generally go unmonitored, making the meaningful analysis of data more difficult. For aerobic fermentations, mass transfer of carbon dioxide can be described in an analogous way to oxygen transfer. The mass transfer coefficient for carbon dioxide is 0.89 times that for oxygen. The maximum dissolved carbon dioxide concentration as a function of exit gas composition is compared with the concentration obtained by assuming equilibrium between the broth and exit gas. The difference between these two concentrations is typically 20–40% of the equilibrium concentration. In large fermenters, a degree of plug flow behavior in the gas and the generally lower specific aeration rates will serve to produce a better approach to equilibrium than for research fermenters.

Carbon dioxide gas delivery to thin-film aqueous systems via hollow fiber membranes

A novel air-to-liquid mass transfer system using wetted rotating membranes was designed to enhance air-to-liquid carbon dioxide (CO2) mass transfer efficiency. Traditional methods, such as sparging, are energy-intensive, but the rotating membrane reduces energy demands by optimising membrane wetting via rotational motion. Experimental tests were conducted using a small-scale system with a membrane width of 0.64 m and loop size of 2 to 5 m, with rotational speeds between 0.0 and 0.78 m/s. CO2 flux increased by up to 45%, achieving maximum uptake rate of 9.14 mg CO2/min/m2 at 100% speed. An empirical model was developed to predict mass transfer rates under varying operational conditions, and model validation showed a strong correlation with experimental data (R 2 = 0.9668). Preliminary techno-economic analysis estimated that scaling the system to meet the CO2 demands of a hypothetical 500,000 L raceway, 915 membranes would be required, utilising ∼223 m2 (13.4%) of 1667 m2 surface area, assuming a 0.3 m depth, 12 g/m2/day growth rate, and algae with 50% carbon by weight. The system’s energy consumption was measured at 17.1 J/g CO2 captured, representing a 90% reduction in power usage compared to conventional sparging systems, which typically require ∼627 W per 8.3 m2 of membrane surface area. Based solely on electricity costs of $0.10/kW-hr, the cost of capturing atmospheric CO2 was estimated at $1550 per ton. This marks a significant improvement over existing technologies, enhancing commercial viability. Future work will validate the system with Chlorella vulgaris and scale to optimise CO2 capture and reduce costs.

Mass transfer of carbon dioxide in anaerobic reactors under dynamic substrate loading conditions

Zeolites are inorganic materials with intrinsic microporous properties. Basically they are aluminasilicates constituted from a three dimensional network of SiO 4 and AlO 4 tetrahedra. This type of materials may have very interesting applications like adsorbents or molecular sieves. In this study, mass transfer properties of supported MFI zeolite membranes at high pressure are established using a new experimental methodology. The aim of this study was the analysis of the mass transfer of a compressed carbon dioxide through microporous zeolite membranes in order to characterize its structural parameters, identifying mass transfer mechanisms under high pressure conditions. This type of materials can be used like molecular sieves, since they present a crystalline structure with interstitial micropores of a mean pore diameter of 0.55 nm. For this purpose, we studied the mass transfer of high pressure CO 2 through microporous MFI zeolite membranes using a new experimental methodology in order to determine the permeance of carbon dioxide using an original apparatus operating in transient state. Carbon dioxide is used in experiments taking into account several applications reported in the literature coupling recovery or separation of this compound from gaseous solutions with inorganic molecular sieves. Values of flux (mol m-2 s-1) and permeance (mol m-2 s-1 Pa-1) have been obtained experimentally. This new experimental device allows estimating permeance values between 3.59 * 10-9 and 7.51 * 10-7 mol m-2 s-1 Pa-1) when the values of feed pressure are ranged between 3 and 14 MPa and the temperature varies between 25 and 100oC. These values are coherent with the microscopic nature of pores, showing that the zeolite layer deposed on the macroporous support was synthesized without macroporous defaults. An activated diffusion through the micropores might be identified in the gas phase, but under supercritical conditions (P > P c , T > T c ) an irreversible modification of transport properties was observed. This behavior was explained by a limited mechanical resistance of the membrane at high pressure conditions. In supercritical conditions, mass transfer could be controlled by a combination of diffusion through mesoscopic and microscopic porosity.

A two-dimensional numeric simulator is developed to predict the nonlinear, convective-reactive, oxygen mass exchange in a cross-flow hollow fiber blood oxygenator. The numeric simulator also calculates the carbon dioxide mass exchange, as hemoglobin affinity to oxygen is affected by the local pH value, which depends mostly on the local carbon dioxide content in blood. Blood pH calculation inside the oxygenator is made by the simultaneous solution of an equation that takes into account the blood buffering capacity and the classical Henderson-Hasselbach equation. The modeling of the mass transfer conductance in the blood comprises a global factor, which is a function of the Reynolds number, and a local factor, which takes into account the amount of oxygen reacted to hemoglobin. The simulator is calibrated against experimental data for an in-line fiber bundle. The results are: (i) the calibration process allows the precise determination of the mass transfer conductance for both oxygen and carbon dioxide; (ii) very alkaline pH values occur in the blood path at the gas inlet side of the fiber bundle; (iii) the parametric analysis of the effect of the blood base excess (BE) shows that (.)V(CO₂) is similar in the case of blood metabolic alkalosis, metabolic acidosis, or normal BE, for a similar blood inlet P(CO₂), although the condition of metabolic alkalosis is the worst case, as the pH in the vicinity of the gas inlet is the most alkaline; (iv) the parametric analysis of the effect of the gas flow to blood flow ratio (QG/QB) shows that (.)V(CO₂) variation with the gas flow is almost linear up to QG/QB = 2.0. (.)V(O₂) is not affected by the gas flow as it was observed that by increasing the gas flow up to eight times, the (.)V(O₂) grows only 1%. The mass exchange of carbon dioxide uses the full length of the hollow-fiber only if Q(G) /Q(B)> 2.0, as it was observed that only in this condition does the local variation of pH and blood P(CO₂) comprise the whole fiber bundle.

Experimental and modeling investigations of solubility and saturated liquid densities and viscosities for binary systems (methane +, ethane +, and carbon dioxide + 2-propanol)

Interfacial properties at elevated pressures in reservoir systems containing compressed or supercritical carbon dioxide

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

Low Emission Conversion of Fossil Fuels with Simultaneous or Consecutive Storage of Carbon Dioxide