In this study, we propose a new mathematical model of dissolved SO3 transport in a glass melting furnace, considering secondary decomposition of sulfate. The calculated concentration of SO3 agrees with measured data near the maximum temperature area, hot spot, in an actual glass tank furnace. The effect of onset temperature of secondary decomposition, the maximum solubility of SO3 and concentration of inlet SO3 on sulfate fining is quantified by simulation.
The growth of L-alanine crystals in a magnetic field in a fluidized-bed crystallizer was investigated. Microscopic observations of the results of crystallization revealed that the c-axes of the L-alanine crystals moving in the solution were parallel to the direction of the applied magnetic field. Furthermore, the degree of orientation of the crystals was examined for various crystal sizes and the magnetic field induction. The surface topography of the grown crystals was observed under a differential interference microscope and an atomic force microscope (AFM). It was found that the orientation of the fine crystals adhered to the surface of the growing crystals and the surface topography of the crystals could be controlled by applying a magnetic field in the fluidized-bed crystallizer.
We have successfully evaluated the lift velocities of spherical particles with diameters of 0.2–1 μm in crossflow microfiltration. The ascending migration of one or multiple particles that were located in a shear field, in the presence or absence of permeation flux, was computed using Newtonian dynamics and the fluctuating Navier–Stokes equation. In the case of a single particle, we found that the lift velocity was proportional to the square of the shear rate and the cube of the particle size. We also evaluated the lift velocity for a multiparticle system to investigate the effect of particle concentration. We found that the lift velocity tended to decrease as the particle concentration increased. We succeeded in performing the first evaluation of the lift velocity for a multiparticle system in the presence of permeation flux. We also showed that the ascent velocity of a particle is the linear sum of the lift velocity and the permeation flux.
Coalbed methane (CBM) is an important energy resource in the world, and to recover this important energy, liquefaction is a good option. Different from ordinary natural gas, CBM usually consists of a lot of nitrogen, which cannot be removed by the ordinary purification technology of LNG. One way of separating nitrogen from CBM is by distillation after liquefaction. In this way, nitrogen is liquefied together with methane, so the liquefaction process and its system performance may be different from that of the ordinary natural gas and will change along with the nitrogen content of CBM feed gas. The liquefaction process adopting a mixed refrigerant cycle with propane pre-cooling is discussed in this paper, which is widely used in LNG liquefaction plants. Taking the unit product liquefaction power consumption as the major index for analysis, the optimum parameters of the liquefaction processes at different nitrogen content of CBM feed gas are worked out, and the corresponding system performance is obtained and compared.
A novel metal monolithic anodic γ-Al2O3 support was prepared by anodization using a clad aluminum plate. The catalytic combustion of methane on Pt/Al2O3/Alloy, Pd/Al2O3/Alloy and Pd–Pt/Al2O3/Alloy catalysts prepared by the impregnation method was studied. The catalysts were characterized by ICP, BET, and temperature-programmed oxidation (TPO). The results showed that at low temperatures (<500°C), both Pd/Al2O3/Alloy and Pd–Pt/Al2O3/Alloy showed high activity, but the activity of Pt/Al2O3/Alloy catalyst was very poor. At high temperatures (>700°C), Pd–Pt/Al2O3/Alloy showed the best activity among these three catalysts, whereas the activity of Pd/Al2O3/Alloy decreased gradually. Therefore, it was concluded that the co-existence of Pd and Pt in the Al2O3/Alloy support in Pd–Pt/Al2O3/Alloy made its activity the best among that of all the catalysts studied over the entire temperature range (400–800°C) considered for methane combustion.
Methods for the application of an adaptive network model are investigated for the estimation of product properties in a semibatch process. The semibatch process exhibits nonlinear behavior, although the process is intensified by inlet flow rate scheduling (IFRS). In the present article, an estimation model based on the adaptive-network-based fuzzy inference system (ANFIS) is considered to flexibly deal with the multiplicity of the semibatch process. We focus on the structure identification of the ANFIS model, and thus propose a model structure where multiple membership functions are set with respect to a measured variable. Then, the adoption of the subtractive clustering method (SCM) is investigated for the determination of initial forms and the number of membership functions. This method results in improving the estimation performance, whereas poor robustness to change in the constant characteristic time in IFRS is seen. Thus, we have come up with the idea of the cascade mode for modifying the model structure. By using the monomer conversion as a cascaded variable, the model structure in the cascade mode is demonstrated to enhance robustness to disturbance and multiplicity in the intensified semibatch process.
Nanodesigning and nanoengineering are key techniques in organic–inorganic synthesis to develop tailor-made materials for advanced applications. Here, we report on a nanocapping technique that is the first to achieve an “ionomer capped inorganic nanoparticle”, and a nanohybrid material composed of a perfluorosulfonated ionomer (PFSI) and a zirconia precursor. The capping between the PFSI and the zirconia precursor was observed only under a narrow range of conditions, and we achieved this by carefully controlling the reaction conditions as well as the amount of chelating agent, catalyst concentration, and PFSI concentration. The capped nanoparticles were analyzed using DLS, TEM, and SAXS techniques. Capping greatly decreased the dimensions of the PFSI to the size of the zirconia nanoprecursor, and also broke down the rigid microphase-separated original structure of the PFSI. Our results also suggest that PFSI was adsorbed on the zirconia precursor via a multipoint adsorption, thereby preventing nanoparticle aggregation. Due to the effective nanocapping, an inorganic concentration as high as 50 wt% could be incorporated into the PFSI matrix without any aggregation occurring. The stability of the nanodispersion was evaluated over a period of one year and was found to be very stable.
A desiccant cooling process equipped with a multi-divided adsorption dehumidifier is proposed to achieve double stage dehumidification in one adsorbent rotor. In this process, once dehumidified and cooled air is dehumidified again at a different adsorption zone of the same desiccant rotor. It has been found experimentally that dehumidifying performance is strongly influenced by the supply position of outside air to the adsorbent rotor. Humid outside air should be supplied to the latter half of the adsorption zone and once dehumidified air should be sent to the first half of the adsorption zone to maintain a suitable adsorption capacity and rate for the whole adsorption zone. Consideration of the appropriate outside air inlet position and the optimal rotation speed yields a 30% larger amount of dehumidification than that of conventional processes under a humid summer condition.
Metal monolithic anodic alumina supported Ru catalysts prepared by impregnation method are employed to the steam reforming of kerosene. The characteristics of the resulting catalysts are analyzed by using ICP, BET, CO-Pulse and temperature-programmed reduction (TPR) measurements. The calcination on the catalyst reactivity is investigated. We found that calcination operation during the catalyst preparation is not an essential procedure; on the contrary, it decreases the catalyst dispersion, further resulting in poor activity. Furthermore, the anodic alumina supported Ru catalyst prepared without calcination at 500°C, provided better activity and stability than a commercial catalyst (S/C = 3.0, F/W = 80,000 mL/(h·g), 450–750°C). In particular, pre-reduction with hydrogen over catalyst is considered to not be an essential operation due to the excellent activity and stability in the reforming reaction.