Gas-solid contact efficiency of a transversely aerated rotary kiln incinerator has proven to be very high. The paper addresses an experimental method to obtain heat and mass transfer coefficients between gas and solid particles in the transverse bed of an aerated rotary kiln incinerator. It is found that the transfer coefficients are sensitive to aeration rate but not to rotation speed. Equations, which correlate the transfer coefficients and relative parameters, are proposed in terms of dimensionless groups to estimate the heat and mass transfer rate in the transverse bed of an aerated rotary kiln incinerator. Furthermore, the temperature distribution in the transverse bed of such a rotary kiln is considered reasonably uniform, which is caused by well distributed inlet gas and solid mixing due to rotation.
Growth rate of Alcaligenes eutrophus under non-explosive gas mixture of low oxygen partial pressure, where oxygen transfer was rate determining process, was enhanced by adding perfluarocarbon as an oxygen carrier. The trend of enhancement with increase of PFC addition was different across the phase inversion region where continuous phase changes from aqueous medium to PFC. The enhancement was analyzed quantitatively using a mass transfer model, which took into account two cases where either the medium or the PFC was continuous phase. An enhancement factor for the oxygen transfer rate, defined as the ratio of oxygen transfer rate in a medium mixed with PFC to that in a PFC-free medium, was used in evaluating the effect of PFC addition. The factor was a function of the oxygen transfer coefficient and the interfacial area between gas bubble and the medium, and the volume fraction of PFC when the medium was in continuous phase. Also the factor varied with the interfacial area and the oxygen transfer coefficient between the PFC and the medium, the volume fraction of PFC and the dissolved oxygen concentration when the PFC phase became continuous. The model revealed the factors affecting on the observed cell growth rate of A. eutrophus, such that the primary factor contributing to the enhancement of the cell growth in the latter case was the increase of the interfacial area between the PFC and the medium.
Solubilities of argon, oxygen and nitrogen were determined in 1,2-propanediol + water mixed solvent over the full range of composition by a static method. Gas solubility measurements were carried out at a temperature of 298.15 K and pressure of 101.33 kPa. Both the excess quantity referring to the Ostwald coefficient and to the excess volume of solvent mixture showed similar relation having minima against the volume fraction composition of 1,2-propanediol. The order of gas solubility expressed by the Ostwald coefficient in 1,2-propanediol + water mixed solvent was argon > oxygen > nitrogen in full range of composition. Furthermore, the excess Ostwald coefficients on the basis of volume fraction which express the non-ideality of gas solubility in non-ideal solutions were defined, and excess Ostwald coefficient of these three solute gases in 1,2-propanediol + water mixed solvent showed one parabolic curve against volume fraction of 1,2-propanediol. This result means that excess Ostwald coefficients of these gases do not depend on the type of solute gas, but on solvent. This property was similar to that of monoalcohol aqueous solutions.
The binary cross second virial coefficient in the mixing rule of Wong and Sandler (1992) can be determined analytically from pure component parameters and activity coefficients at infinite dilution. The modification allows to determine the binary interaction parameter without the additional minimization of excess Gibbs energy deviations. At low pressures, the accuracy of the modification is comparable to that of the original model. High pressure phase equilibria were predicted by the modification of the Wong-Sandler mixing rule with Modified UNIFAC and ASOG group contribution methods.
The effect of hydrodynamic stress on intracellular factors of plant cells was investigated. Safflower (Carthamus tinctorius) cells were cultivated in a stirred tank reactor. The aggregate size distribution was determined with an image analyzer and it was confirmed that the aggregate size became smaller in a stirred tank. The resultant changes in the cells were evaluated on the basis of cell number, dry cell weight, cell viability, ATP amount and cell membrane fluidity. The viability was estimated by growth potential, membrane integrity and respiration activity of the cells. The cells were damaged by hydrodynamic stress in the respiration activity before the occurrence of the cell lysis and the damage of membrane integrity. ATP amount decreased as the agitation rate increased. The extent of ATP loss was larger than that of viability loss. These results indicated that hydrodynamic stress affected the metabolic system and that the loss of viability was probably due to this metabolic change. The degree of ATP reduction showed a power law dependence on the power dissipation rate per unit mass, ε, which is calculated from agitation rates.
A corresponding-states model with oxygen, octane and water as the reference fluids was developed for correlating the thermal conductivity of liquids and liquid mixtures. This model was applicable to most liquids over wide ranges of temperature and pressure. With a binary interaction constant, the model yielded good results for binary solutions at atmospheric pressure and could be reasonable extrapolated to elevated pressures. The prediction was satisfactory for ternary mixtures when the cross interaction constants determined from the respective equal-molar binary mixtures were employed.
Functional microcapsules encapsulating stearic acid were prepared by in situ polymerization of styrene and divinylbenzene. Morphology and release rate were investigated by changing preparation conditions. Total monomer concentration was found to be an important determinant of morphology while being a less dominant factor in average diameter of microcapsule. The sustained release of stearic acid was controlled by pore diffusion through porous microcapsule membrane. The permeability was dependent upon total monomer concentration and average diameter of microcapsule. The permeability coefficient increased with an increase of average diameter of microcapsules and decreased with increasing total monomer concentration. The sustained release rate from microcapsules to ambient solution abruptly changed in the vicinity of melting point of stearic acid. This may indicate that functional microcapsules exhibiting temperature-dependent permeability can be prepared.
Measurements of the rates of condensation of a steam, methanol and benzene vapor in the presence of air on a short horizontal tube for wide ranges of inlet air concentrations and vapor flow rates were carried out. The observed vapor phase heat and diffusion fluxes were compared with results of the authors’ previous numerical solution to heat and mass transfer on a cylinder with diffusive surface mass suction and injection under laminar forced flow conditions. By considering the results of our previous numerical solution and the present experiments, a new method for simulation of condensation of vapors in the presence of noncondensable gas on a short horizontal tube was proposed and compared with the experimental data. The effect of noncondensable gas on the rate of condensation was also discussed.
Dry and wet grinding of EP dust containing mainly carbon and ammonium sulfate with small amounts of metal compounds were carried out by using three types of grinding mills. The characteristics of ground specimen and solubility of metal compounds in distilled water were investigated by XRD, EPMA, SEM, particle size distribution measurement and ICP analysis. Aggregation of fine particles occurred in dry grinding with increase in grinding time, while continuous size reduction of the ground specimen occurred in wet grinding. Dry grinding of EP dust causes structural change from crystalline metal compounds to amorphous ones. The water solubility of vanadium compound in the specimen ground under dry condition increases with an increase in grinding time, while that of nickel and iron compounds are almost independent of grinding time. The maximum concentrations of vanadium are about five to six times higher than those for the original unground specimen. Wet grinding does not contribute to the improvement in solubility of metal compounds.
Distribution data of citric acid between an aqueous solution and a xylene solution of tri-n-octylamine (TOA) were measured in the 283–323 K temperature range. The complexes formed in the organic phase were determined and the equilibrium constants for the formation of these complexes were evaluated. In addition, the apparent thermodynamic data and the mole fraction of each complex present in the organic phase were calculated. When citric acid was extracted with a mixture of TOA and di(2-ethylhexyl) phosphoric acid (D2EHPA), the synergistic and antagonistic effects, depending on either the excess TOA over D2EHPA or the excess D2EHPA over TOA, were also observed and discussed.
Equilibrium adsorption behavior of divalent metal ions onto hydrous titanium (IV) oxide (HTO) was studied. A general equilibrium adsorption equation was derived from three simultaneous equilibrium reactions: (1) hydrolysis of metal ions to the hydroxides, (2) deprotonation of hydroxyl groups (adsorption sites) on HTO’s surface and (3) complexation, of the hydroxides with the deprotonated sites. The theoretical equilibrium adsorption equation was confirmed by several experimental results under acidic or basic conditions using uranium, lead, cadmium and zinc ions as the adsorbates. It is demonstrated that two parameters within the equation provide information about the adsorption capacity and the selectivity of adsorbent for target metal ions. The HTO employed here had available sites of 7.15 × 10–4 mol·g–1 for all experiments. Metal ions were adsorbed preferentially on the HTO in the following sequence: Zn2+ < Cd2+ < Pb2+ < UO22+.
Vapor-Liquid Equilibrium (VLE) calculations have been made on binary and ternary azeotropic mixtures using the Peng-Robinson equation of state (EOS). Various mixing rules of the van der Waals one-fluid model, the local composition model and the group-contribution model for the VLE computations were discussed. In the group-contribution model, we applied the Huron-Vidal method and determined the EOS parameters for mixtures from the UNIFAC activity coefficient model. This study compares the phase equilibrium calculations and investigates the prediction of azeotropic properties. It was shown that the group-contribution mixing model yielded satisfactory results, and provided a superior calculation method to other mixing rules or correlation equations.
Three types of L-phenylglycine-rixed membranes were prepared by varying casting conditions. The optical resolution of racemic phenylglycine (DL-Pgly) was performed by pressure gradient. L-Pgly-fixed membranes were permeable in preference to D-Pgly to L-Pgly, and the maximum separation factors of respective membrane under the operating conditions were 9.1, 8.6 and 2.7. Apparent self-association constants were evaluated from the dialysis data. By applying these values to the basic solute flux equations at a given pressure gradient, the values of the viscous parameters were evaluated. The ratio of viscous parameter of D-Pgly to that of L-Pgly depended on the apparent self-association constant. The separation factor was successfully represented on the basis of the basic solute flux equations including the apparent self-association constants, and the separation factor became larger in denser membranes with low volume flux.
The effect of NAA (1-naphthaleneacetic acid) treatment on emergence of adventitious roots was examined in the process of root regeneration using cell aggregates derived from horseradish hairy roots. The number of emerging roots was significantly larger from those cell aggregates with increasing amounts of NAA absorbed by the cells. The cell aggregates with absorbed NAA of 11.3 to 17.1 × 10–3 kg/kg-dry cells formed 3.4 to 3.7 × 105 roots per m2-aggregate surface area during the culture period of 456 h, indicating an 8- to 9-fold increase over that of cell aggregates without the treatment. The large number of available roots emerging from cell aggregates with the NAA treatment consequently led to enhanced rates of root growth and sugar consumption in a batch culture for root regeneration. The kinetic behavior of root regeneration culture was described successfully on the basis of a model of branching root growth.