Hitoshi Kosuge

Study on removal of cadmium from wastewater by emulsion liquid membrane

Removal of cadmium from wastewater using emulsion liquid membrane (ELM) is studied in the present study. A polyamine-type surfactant was used for stabilizing the emulsion phase. Tri-iso-octyl amine (TIOA) has been used as a carrier for transferring of cadmium through the membrane. The results show good performance in the separation process. To determine the optimum operation conditions, the effect of several parameters such as surfactant concentration, carrier concentration, pH of external and internal phases, oil to internal phase volume ratio, emulsion to external phase volume ratio, solvent type, solute concentration, presence of iodide and chloride in external phase, and mixing conditions have been investigated.

Isobaric vapor-liquid-liquid equilibria with a newly developed still

Abstract A new and simple apparatus for the measurement of isobaric vapor–liquid–liquid equilibrium (VLLE) is developed by modifying the still proposed by van Zandijcke et al. The still is used to measure the isobaric vapor–liquid equilibrium (VLE) data for the system ethanol–water, the isobaric VLE and VLLE data for the binary systems water–1-butanol and 2-butanol–water at atmospheric pressure. The obtained data for the binary systems are compared with the previous data in the literature. The thermodynamic consistencies of the obtained data for the binary systems are confirmed by the Herington’s area test. Furthermore, the isobaric VLLE data for the ternary systems ethanol–water–1-butanol and ethanol–2-butanol–water are obtained with the apparatus. The results show that the apparatus can be applied to the measurements of both isobaric VLE and VLLE successfully.

Simulation and optimization of heterogeneous azeotropic distillation process with a rate-based model

A rate-based simulation method for sieve tray columns is developed with the correlations of clear liquid height and mass transfer rate that were obtained in our previous experiments of the homogeneous and heterogeneous ternary distillation with a sieve tray column. The simulation method is applied to an ethanol dehydration process that consists of a dehydration column and an entrainer recovery column. In the simulation study, the effects of tray specification, overhead vapor concentration, locations of main feed and recycle flow, reflux ratio and recycle flow rate on separation performance of the columns are investigated. The simulation results show that increase of the reflux ratio and recycle flow rate decreases the necessary number of trays of the dehydration column to achieve a specified separation, but it increases the heat duties of the process. Then, the economical analysis of the process is carried out, and the optimum operation conditions of the process are discussed.

Hydrodynamics and mass transfer in heterogeneous distillation with sieve tray column

Abstract Hydrodynamics and separation performance of a sieve tray column in heterogeneous distillation are studied experimentally under total reflux conditions. A correlation for clear liquid height in the heterogeneous liquid region is obtained by modifying the correlation of the homogeneous systems. The volumetric dimensionless diffusion fluxes in the heterogeneous liquid region are smaller than those in the homogeneous liquid region. This may be due to the mass transfer resistance in the liquid phases. In order to examine the effect of liquid-phase resistance on separation performance, a simulation is carried out by either considering or neglecting the liquid-phase resistance. The simulation shows that the liquid-phase resistance affects the vapor-phase concentration driving forces, volumetric diffusion fluxes and convective mass flux in the heterogeneous liquid region. It also shows that the predicted top vapor concentrations and flow rate are in reasonable agreement with the experimental data in the heterogeneous liquid region by considering the liquid-phase mass transfer resistance.

Mechanical Entrainment in W/O/W Emulsion Liquid Membrane

Abstract An experimental study of mechanical entrainment in W/O/W emulsions is conducted. W/O/W emulsions are stirred for various stirring times under the conditions that mechanical entrainment solely occurs, and changes in volume of the W/O emulsions and size distribution of the internal water droplets are measured. The rate of change in number of the water droplets entrained is found to be proportional to the volume fraction of W/O emulsions. Based on this result, a new model for mechanical entrainment is developed. The calculated change in W/O emulsion volume with time agrees with the observed ones except in the region near phase inversion. Then, phase inversion is discussed.

Solid‐Liquid Extraction of Taxane Compounds from Yew Needle

Abstract Solid‐liquid extraction of the taxane compounds in yew needles is carried out with methanol. The concentration of each component in the raffinate is estimated from the observed concentration in the extract and material balance equations with a solvent‐permeation model that solvent permeates the solid. The obtained distribution coefficient is found to be independent of the particle size. It suggests a possibility that the extract is in equilibrium with the liquid solution in the raffinate. Based on the experimental results, the effect of operating conditions on separation performance of countercurrent‐multistage extraction is studied by using the ideal stage calculation.

EXPERIMENTAL STUDIES OF DIFFUSION FLUXES F TERNARY DISTILLATION OF THE ACETONE-METHANOL-ETHANOL YSTEMS BY A WETTED-WALL OLUMN

Measurements of mass and diffusion fluxes for ternary distillation of the acetone-methanol-ethanol systems were made by a wetted-wall column under total reflux conditions for wide ranges of the liquid concentrations. Intermediate component methanol showed peculiar behavior of a finite mass flux near the zero-driving force region. This was explained as being due to the effect of the interfacial velocity caused by mass fluxes of the other components. The diffusion fluxes were shown to be proportional to concentration driving forces, whereas the mass fluxes were not. Discussions on the use of the number of transfer units for correlation of mass transfer data in ternary distillation were also made.

SEPARATION OF TAXANE COMPOUNDS BY LIQUID-LIQUID EXTRACTION

Experimental and numerical studies on liquid-liquid extraction of taxane compounds that are extracted from yew needles by solid-liquid extraction are carried out. In the treatment, the materials are classified to three components, and separation of component C from components A and B is discussed. In experiments, distribution coefficients and selectivities of those components are measured with various solvents. Based on the experimental results, numerical simulation of the countercurrent multistage liquid-liquid extraction process for separating the components is carried out with various operating conditions. Then, the fractional countercurrent multistage liquid-liquid extraction process is examined, and the effect of reflux operation on separation performance of the fractional liquid-liquid extraction process is studied. Based on the numerical results, it is found that the fractional countercurrent multistage liquid-liquid extraction with reflux is superior to the other extraction processes for separating taxane compounds.