Outstanding Paper Award Subcommittee of Journal of Chemical Engineering of Japan has assessed the 171 papers published in 2006, corresponding to volume 39 and selected the candidates of the award. As a result, the editorial board finally selected the five papers for JCEJ Paper Awards of 2006; those are the papers on “Preparation and Gas Permeation Properties of Composite Carbon Molecular Sieve Membranes Derived from Polyimides with Thermally Decomposable Sulfonic Acid Salt and/or Hexafluoroisopropylidene Group,” “Application of Association Model for Solubilities of Alkali Metal Chloride in Water Vapor at High Temperatures and Pressures,” “Epitope Screening by Use of a Random Peptide-Displayed Phage Library and Polyclonal Antibody-Coupled Liposomes,” “Crystallization of Ergosterol from Hexane Solution by a Continuous Column Crystallizer Equipped with a Water Feeding System,” and “Numerical Investigation of Local Oxygen Injection Effect on Argon Induction Plasmas Using a Chemically Non-Equilibrium Model“.

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The kinetics of the solid-state polymorphic transition of theophylline anhydrates from the metastable phase (Form III) to the stable phase (Form II) were studied and the effect of humidity on the transition kinetics was quantitatively analyzed. Relative humidity of environments was found to be the major controlling factor for the transition. In order to describe quantitatively the kinetics, a serial kinetic model comprised of the first order reaction followed by the penetration of moisture in the crystalline anhydrate phase was proposed. The two rate constants in the serial model, i.e., the reaction constant and the apparent mass transfer coefficient, were correlated as functions of temperature and relative humidity. A chart for the prediction of time necessary to complete the transition in terms of temperature and humidity was presented.

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A new coal combustion technology for a large-scale power plant is required to be applicable to various kinds of coal. An oxygen-blown pulverized coal combustion experiment was investigated with a bench scale apparatus to understand such characteristics as the combustion efficiency, NO_x concentration, conversion from fuel-N, the unburned fraction and composition of mineral matter in the collected ash. The experiment was conducted in a down-fired, cylindrical and vertical furnace. The primary oxygen is injected into the ejector to carry coal particles to the burner, and the swirled secondary one is fed through an annulus. The CO₂ concentration in flue gas was much higher than that of air–coal combustion, and the value was eight out of ten. The results made a feasible condition for CO₂ separation and sequestration. The NO_x emission was ranged in concentrations from 1650 to 1800 ppm in the complete combustion region. The NO_x concentration was much higher, however the NO_x conversion ratio was about the same level as the case of air combustion. The decrease of low-boiling component such as Na, Mg, K and Ca was identified because the flame temperature of the oxygen-blown coal combustion was achieved about 3000 K. We suggested the vaporized calcium components in the fly ash have a potential of the furnace desulfurization and the effect of SO_x attack to the heat exchanger was inhibited.

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The contribution of ionic reactions to phenol oxidation has been investigated in subcritical and supercritical water. From the experiments conducted at 24.7 MPa, it was found that the phenol conversions at 360°C were slightly higher than that at 400°C. We calculated the concentration of phenolate anion at 24.7 MPa using semiempirical model reported by Sue et al. (2002). The calculated concentration of phenolate anion at 360°C is about seventh order of magnitude higher than that at 400°C because of the high ion product of water at 360°C. The electron transfer (ET) reaction (C₆H₅O^– + O₂ = C₆H₅O· + O₂^–) was investigated as one of the reasons for the enhancement of phenol oxidation in subcritical water. We estimated the equilibrium constant of the ET reaction using density functional theory calculations, which suggests that the ET reaction should be taken into consideration in the region of high ion product of water. We also discussed the dimerization reaction as consumption reactions of phenoxy radical and other reactions involving inorganic ion species such as O₂^–, OH^– and HO₂^–. When phenoxy radical and O₂^– are produced effectively, these reactions could be more favorable in subcritical water than in supercritical water. From these discussions, phenol oxidation in subcritical water could be enhanced by the ionic reaction mechanism because of a high ion product of water.

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This study examined foam breaking characteristics of a mechanical foam-breaker using shear force (MFUS) between a fixed orifice plate and a rotating disk fitted to a stirred-tank reactor (STR). The effects of operating conditions on the liquid holdup in foam φ_L and the volumetric rate of foam flow Q_a, which reflect the foaming behavior of the STR, were revealed. The foam-breaking behavior of the MFUS was investigated from changes in the foam density after foam breaking (ρ_f)_c, which remained constant at a disk rotational speed N, transitional disk rotational speed N_t, and shearing power P_s. The value of (ρ_f)_c decreased concomitant with the increase in the mass flow rate of liquid in the foam flowing into the orifice, w_L. The N_t became larger concomitant with the lower average ascending velocity of the foam U_a and higher φ_L. The magnitude of P_s was related to that of w_L. Empirical equations for predicting (ρ_f)_c, N_t and P_s were obtained based on those results.

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Lipase-catalyzed transesterification of olive oil with ethanol to produce biodiesel was studied. Operation optimization with low cost lipase, Lipase OF, was proposed. The conversion was low because Lipase OF had low resistance for ethanol. To prevent deactivation, a hydrolysis–esterification two-stage system was employed. Ethanol was added in three ways, adding at once, dividing ethanol into 3 and continuous feed. Introducing ethanol continuously by a pump had the highest conversion. Also diluted ethanol improved the conversion. Fermentation raw ethanol can produce almost the same amount biodiesel as the diluted reagent.

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This paper presents an optimal PID controller using a new loop-shaping procedure which is developed by pushing all two zeros formed by the PID controller closely to a larger pole of the second order process to improve the sensor noise attenuation in high frequency regions. And it formulates the optimization problem minimizing the gains of the PID controller in order to reduce the high gain problem and consider such time domain design specification as maximum overshoot as well as frequency domain design specification.

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We have developed enzyme-encapsulated microcapsule reactors in which the reaction rates are controlled by specific ions. A microcapsule was integrated with enzymes in the core and ion-responsive polymers grafted onto the walls of the pores in the shell membrane. In this research, glucoamylase was selected as the reaction device in the core and the copolymer of N-isopropylacrylamide and benzo-18-crown-6-acrylamide was used as an ion-responsive device. Our ion-responsive microcapsule reactor was developed by preparing porous microcapsules using a combination of the SPG membrane emulsification technique and interfacial polymerization following plasma-graft polymerization to graft ion-responsive polymers to the shell membrane’s pores for the ion-responsive gate function. This was followed by transglutaminase treatment to immobilize the enclosed glucoamylase in the core. The ion-responsive gate performance was independent of pH and the permeability of starch was controlled using K⁺ or Ba²⁺ ion signals. A fivefold permeability difference was achieved using a 0.1 M Ba²⁺ signal at pH 4.6 and 40°C. This difference was caused by the pores opening and closing; that is, the pores in the shell gate were open in the absence of the specific signal ion because of the shrunken states of the gate polymers, while the pores were closed in the presence of the specific signal ion because of the swollen states of the gate polymers. Furthermore, we showed the efficiency of the transglutaminase treatment method for preventing the enclosed enzymes leaching through the environment-responsive microcapsule shell membranes. Finally, we achieved a reactivity difference of 2.2 times in our enzyme-enclosed ion-responsive microcapsule reactors using 0.1 M of Ba²⁺ signal at pH 4.6 and 40°C, resulting from the permeability difference in response to the ion signal, not from the changes in the enzymatic activity itself.

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The removal properties of aqueous phosphate with commercially available boehmite were compared with those with a corresponding compound prepared by the sol–gel method. It was found that the removal rate when using the prepared boehmite was evidently greater than that using the commercial reagent. The removal rate using the prepared boehmite was strongly influenced by the amount of acid added in the peptization step during the sol–gel preparation. As a development of the boehmite utilization, a glass plate was coated with boehmite and utilized for the removal and regeneration of aqueous phosphate. The removal rate of aqueous phosphate was dependent on the dip-coating times and the preparation method of the precursor sol. It was also described that the removed phosphate could be eluted from the coated plate with aqueous ammonium, suggesting that boehmite film can be employed for the continuous removal and regeneration of aqueous phosphate.

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