Efficiency of water removal from water/ethanol mixtures using supercritical carbon dioxide

Rodrigues, Miguel A.; Li, Jun; Almeida, António J.; Matos, Henrique A.; Azevedo, Edmundo Gomes de

doi:10.1590/s0104-66322006000200007

Cited by 13 publications

(6 citation statements)

References 4 publications

(4 reference statements)

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“…This is because the CO 2 /water parameters from eq 13 give a very good description of the water content in the vapor phase at low ethanol concentration of the liquid phase, as Figure 10 shows. Table 7 also shows that the calculated results from an empirical method 13 fit well the data; yet, in most cases, it slightly underestimates the CO 2 consumptions.…”

Section: Water Removalmentioning

confidence: 74%

“…Calculation Method. A step-by-step procedure 13 and the PRSV-EoS were used to calculate the relevant quantities in the experimental process described above. The first step was to determine the initial working point at the system's pressure (10.0 MPa) and temperature (313.2 K) from the initial feed of the aqueous ethanol a Binary interaction parameters obtained using the alternative objective function, AAD ) AADx ) Here n in should be small enough to keep the results steadily unchanged; our calculations showed that 1% or less of the initial CO 2 mole number was a convenient choice (experiment also required that CO 2 flow rates should be small enough, here 3-7 g min -1 that was small compared to the total CO 2 consumed).…”

Section: Water Removalmentioning

confidence: 99%

“…Because of the present unsuccessfully phase equilibrium calculations by means of equations of state on this ternary system, we recently 13 extended the empirical method established by Duarte et al 14 for the evaluation of the water removal efficiency from ethanol solutions by high-pressure CO 2 . Also, Budich and Bru ¨nner 15 reported an empirical method applied to extraction column calculations.…”

Section: Introductionmentioning

confidence: 99%

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VLE of Carbon Dioxide/Ethanol/Water: Applications to Volume Expansion Evaluation and Water Removal Efficiency

Li¹,

Rodrigues²,

Matos³

et al. 2005

Ind. Eng. Chem. Res.

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The Peng-Robinson equation of state (PR-EoS) and the Stryjek and Vera modification of the Peng-Robinson equation of state (PRSV-EoS) were used to predict the vapor-liquid equilibrium of the system carbon dioxide(1)/ethanol(2)/water(3) under various temperatures and pressures. We propose a new algorithm that uses a flash calculation to provide a set of initial values and then solves the highly nonlinear phase equilibrium equations using the Broyden modified Newton-Raphson (BNR) method. With interaction parameters for the constituent binary systems, the ternary vapor-liquid equilibrium prediction shows that, at a given temperature, pressure, and water molar fraction in liquid phase, this algorithm is stable to calculate all other compositions. The calculated results from both the PR-EoS and the PRSV-EoS are in good agreement with the experimental data for the binary and ternary systems. A water removal process using supercritical carbon dioxide was experimentally implemented. The pressure dependence of the volume expansion of the mixture ethanol/water with carbon dioxide was also investigated using a high-pressure view cell. The established phase equilibrium calculation was applied to predict the volume expansion behavior and to evaluate the water removal efficiency. Results show that this ternary phase equilibrium calculation is useful to study the water removal process under high pressure carbon dioxide. It also shows that the volume expansion prediction is good at relatively low ethanol mass fraction in the feeding water/ethanol mixture or at low pressures.

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Section: Water Removalmentioning

confidence: 74%

Section: Water Removalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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VLE of Carbon Dioxide/Ethanol/Water: Applications to Volume Expansion Evaluation and Water Removal Efficiency

Li¹,

Rodrigues²,

Matos³

et al. 2005

Ind. Eng. Chem. Res.

Self Cite

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“…The former represents a new generation of membrane separation process involving a phase change to form a gaseous permeate and liquid retentate using a semipermeable membrane, whereas the latter employs molecular sieves or biomaterials (e.g., corn grits, cassava starch) to selectively adsorb water. − Another process for dehydrating ethanol is supercritical fluid extraction, in which carbon dioxide is employed as the solvent. Liquid CO 2 is used to extract the ethanol, and then CO 2 is flashed off by depressurization to recover anhydrous ethanol . However, regardless of whether they are distillation or nondistillation technologies, all of the above processes involve either considerable energy consumption or huge capital investments because of their complex process configurations.…”

Section: Introductionmentioning

confidence: 99%

Simulation and Analysis of a Reactive Distillation Column for Removal of Water from Ethanol–Water Mixtures

Lin

Chen

et al. 2014

Ind. Eng. Chem. Res.

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A novel approach to removing water from near-azeotropic ethanol−water mixtures is proposed based on the hydration of ethylene oxide (EO) to produce ethylene glycol (EG) in a reactive distillation (RD) column. Steady-state simulations using the Aspen Plus software package were carried out to investigate the feasibility of the suggested approach, and a sensitivity analysis was carried out to obtain the optimal design parameters. The results showed that, using the optimal operating conditions, a reactive distillation column is capable of circumventing the azeotropic limitation to obtain anhydrous ethanol. Compared with traditional approaches, the proposed approach is promising because of its great potential for reducing energy consumption and capital costs.

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“…Hence, the use of O/W emulsions in the place of solvent requires a process setup in order to improve water solubility in SC-CO 2 . For instance, the water removal efficiency can be raised by increasing the pressure and temperature [47].…”

Section: Technologies For β-Carotene Encapsulation In Dried Systemsmentioning

confidence: 99%

Kinetic Study of Encapsulated β-Carotene Degradation in Dried Systems: A Review

Lavelli

Sereikaitė

2022

Foods

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β-Carotene serves as a precursor of vitamin A and provides relevant health benefits. To overcome the low bioavailability of β-carotene from natural sources, technologies have been designed for its encapsulation in micro- and nano-structures followed by freeze-drying, spray-drying, supercritical fluid-enhanced dispersion and electrospraying. A technological challenge is also to increase β-carotene stability, since due to its multiple conjugated double bonds, it is particularly prone to oxidation. This review analyzes the stability of β-carotene encapsulated in different dried micro- and nano-structures by comparing rate constants and activation energies of degradation. The complex effect of water activity and glass transition temperature on degradation kinetics is also addressed, since the oxidation process is remarkably dependent on the glassy or collapsed state of the matrix. The approaches to improve β-carotene stability, such as the development of inclusion complexes, the improvement of the performance of the interface between air and oil phase in which β-carotene was dissolved by application of biopolymer combinations or functionalization of natural biopolymers, the addition of hydrophilic small molecular weight molecules that reduce air entrapped in the powder and the co-encapsulation of antioxidants of various polarities are discussed and compared, in order to provide a rational basis for further development of the encapsulation technologies.

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Efficiency of water removal from water/ethanol mixtures using supercritical carbon dioxide

Cited by 13 publications

References 4 publications

VLE of Carbon Dioxide/Ethanol/Water: Applications to Volume Expansion Evaluation and Water Removal Efficiency

VLE of Carbon Dioxide/Ethanol/Water: Applications to Volume Expansion Evaluation and Water Removal Efficiency

Simulation and Analysis of a Reactive Distillation Column for Removal of Water from Ethanol–Water Mixtures

Kinetic Study of Encapsulated β-Carotene Degradation in Dried Systems: A Review

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