Showing papers in "Journal of Chemical Engineering of Japan in 2012"

Recent Advances in Internally Heat-Integrated Distillation Columns (HIDiC) for Sustainable Development

Abstract: Keigo Matsuda1,2, Koichi Iwakabe2 and Masaru Nakaiwa2 1 Business Research Institute for Glocal Innovation, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa-shi, Yamagata 992-8510, Japan 2 Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba-shi, Ibaraki 305-8565, Japan

Improvement of the Deethanizing and Depropanizing Fractionation Steps in NGL Recovery Process Using Dividing Wall Column

Abstract: In this work, our aim is to utilize a dividing wall column to improve the performance of the deethanizing and depropanizing fractionation steps in natural gas liquid processing. Starting from an initial conventional column sequence, the initial designs of the conventional dividing wall column and a top dividing wall column are obtained by maintaining the number of trays. In succession, they are optimized to reduce the energy consumption using factorial design. The results show that the conventional dividing wall column and the top dividing wall column can offer many benefits to the system, e.g., curbing the operating cost including refrigeration cost, and minimizing the reboiler and condenser duty. Furthermore, by using a dividing wall column, both the purity of ethane and its recovery rate are increased. The influence of utility prices on the operating cost saving of the conventional and the top dividing wall columns is also investigated. In addition, to further enhance the dividing wall column performance, heating is integrated on the top and an interreboiling system is installed at the bottom section of the dividing wall column.

Production of Fine Organic Crystalline Particles by Using Milli Segmented Flow Crystallizer

Abstract: In the pharmaceutical production field, it is required to produce organic fine crystalline particles having a monodispersed crystal size distribution (CSD). Anti-solvent crystallization is one method for producing crystal particles. In order to produce fine crystalline particles and/or crystals having a monodispersed CSD, several methods such as segmented flow in the tubular crystallizer, ultrasound irradiation, and modulated operation in batch cooling crystallization have been studied in previous studies. In this study, integrated operation of ultrasound irradiation and temperature modulation at a milli-sized segmented flow has been carried out to produce organic fine crystalline particles having a monodispersed CSD in the anti-solvent crystallization. Taurine (solute)–water (solvent)–EtOH (anti-solvent) system is employed. The effect of segmented flow on mixing solution has been observed with a high-speed microscope. Fine crystalline particles which have tens of microns average size are obtained with the integration of ultrasound irradiation and temperature modulation on a milli-sized segmented flow. Furthermore, crystals of 10 µm size are produced under controlled supersaturation condition. Additionally, it is suggested that the CSD could be improved by introducing temperature modulation after nucleation.

Definition of the New Mean Particle Size Based on the Settling Velocity in Liquid

Abstract: New analysis and a definition of the new mean particle size have been discovered by rediscussing theory of the buoyancy weighing-bar method, which is a type of sedimentation methods. This paper proposes a new mean particle size based on the settling velocity in liquid. The velocity mean size of all particles [equation], which is the new mean particle size defined in this paper by the buoyancy weighing-bar method, is given as follow.[equation]ΔGi is the buoyancy difference mass of particles xi. Homogenous particles and a ternary mixture of spherical glass beads are used as the samples. Although the buoyancy weighing-bar method is also time-consuming, the maximum particle size and the mean particle size can be derived within a short time after initiating measurement.

A New Method for Flow Regime Identification in a Fluidized Bed Based on Gamma-Ray Densitometry and Information Entropy

Abstract: The accurate identification of the boundaries of the main flow regimes in fluidized beds is very important since the degrees of mixing and mass and heat transfer depend on the prevailing flow regime. Both the minimum fluidization velocity Umf (0.103 m·s−1) and the transition velocity Utrans (0.12 m·s−1) to bubbling fluidization regime have been successfully identified based on a newly developed maximum information entropy (IEmax) algorithm applied to gamma photon time series. The latter are recorded by means of gamma-ray densitometry scans performed in an air–polyethylene fluidized bed (0.438 m in ID) operated at ambient conditions. A comparison with the Kolmogorov entropy (KE) algorithm has found that the new approach yielded more accurate transition velocities. The value of Umf is also validated by means of the profiles of both bed pressure drop and bed height, respectively. It has been found, however, that these parameters are not capable of identifying the second transition velocity Utrans. It is demonstrated that the Umf value identified on the basis of IEmax is theoretically predictable. In the bubbling fluidization regime, a simple correlation between both the KE and IEmax values is developed.

Mixing Rules Based on Power Means and Generalized q-Fractions

Abstract: The linear blending rule (LBR) is the simplest mixing rule linking physical properties with mixture composition. It is just a composition-weighted arithmetic mean over the pure component property values. Unfortunately, the composition dependence of most mixture properties shows nonlinear deviations from the LBR. The conventional approach is to use higher-order Scheffe polynomials. However, this introduces cross-parameters that characterize nonlinear blending effects and that require extensive mixture data for their evaluation. Instead, we propose new parameter-sparse mixing rules that feature pure component parameters only. The new mixing rules were constructed by (i) employing composition-weighted power means, (ii) transforming the composition variables via Wohl’s q-fraction concept, and (iii) combinations of these two approaches.

Marangoni flows in polymer solution droplets drying on heating surfaces

Abstract: The effect on substrate temperature on the fluid dynamics in a polymer solution droplet evaporating on a substrate is investigated experimentally and numerically. It is found from the experiments that fluid velocities in the droplets increase with increasing initial substrate temperature and with decreasing initial solute concentration. A mathematical model, which takes thermal and solutal Marangoni effects into account, are numerically solved using a finite element method. The calculated fluid velocities agree with the experiment. Both experiments and calculations show that, though thermal Marangoni forces dominate the fluid dynamics, solute Marangoni forces should never be neglected. The calculations predict that solute Marangoni effects are more emphasized with decreasing contact angle.

Photocatalytic Activity of Magnetically Separable TiO_2/SiO_2/Fe_3O_4 Composite for Dye Degradation

Abstract: In the present study, a magnetically separable photocatalyst (TiO2/SiO2/Fe3O4) has been prepared and used for the photooxidation of methyl orange (MO) dye. The effects of various reaction conditions such as dye concentration, catalyst dose, and pH on the reaction rate were investigated to enhance the photooxidation process. Thephotocatalytic oxidation of MO was found to follow half-order kinetics. The optimum reaction conditions were found to be a 2000 ppm TiO2 catalyst dose in an acidic medium. A higher catalyst load had no effect on the degradation rate. The dye concentration negatively affected the reaction rate because of the reduced light transmittance inside the photoreactor. The catalyst could be reused several times with nearly the same activity and thus the final cost of the treatment process could be reduced.

Preparation of Sulfo-Group-Bearing Mesoporous-Silica-Based Solid Acid Catalyst and Its Application to Direct Saccharification

Abstract: A series of sulfo-group-bearing mesoporous silica (SBA-15) catalysts were prepared using a one-step hydrothermal synthesis method. The e ect of preparation conditions on the structure and acidic nature of the prepared solid acid catalysts was investigated. The characterization results of the prepared solid acid catalysts indicate that most of the sulfur atoms in mercaptan were oxidized and converted into sulfo groups through a reaction with hydrogen peroxide and that the SBA-15 structure was retained in all the catalysts after the oxidation. The catalytic performance of the prepared solid acid catalysts in the sacchari cation of cellulose and rice straw was investigated; an autoclave was used for the saccharication. A maximum glucose yield of 27% and a maximum total monosaccharide yield of 21% were obtained when the sacchari cation of cellulose and rice straw was carried out using a MPS-D catalyst, respectively.