JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Online ISSN : 1881-1299
Print ISSN : 0021-9592
Volume 54, Issue 12
Displaying 1-6 of 6 articles from this issue
Editorial Note
Particle Engineering
  • Tianqi Liu, Zhixin Cai, Ruicheng Sun, Ning Wang, Ruiheng Jia, Weiye Ti ...
    Article type: Research Paper
    2021 Volume 54 Issue 12 Pages 631-637
    Published: December 20, 2021
    Released on J-STAGE: December 20, 2021
    JOURNAL RESTRICTED ACCESS

    To reveal the flame propagation characteristics of the deposited coal dust explosion driven by airflow carrying the coal dust, the horizontal glass tube explosion apparatus is used for experimental testing. The greater the degree of coal dust metamorphism, the smaller the propagation distance and duration of the explosion flame. The propagation distance and duration of the explosion flame first increase, then decrease as the weight of the deposited coal dust increases due to the limited space in the glass tube, local turbulence disturbance, and insufficient oxygen concentration. As the particle size of the deposited coal dust increases, the flame duration of lignite and long-flame coal decrease, but the flame duration of non-stick coal and gas coal increase. Inert rock dust effectively hinders the coal dust explosion, confirming that spreading inert rock dust around the tunnels effectively reduces the explosion of suspended and deposited coal dust.

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Separation Engineering
  • Bimala Pangeni, Hari Paudyal, Katsutoshi Inoue, Keisuke Ohto, Hidetaka ...
    Article type: Research Paper
    2021 Volume 54 Issue 12 Pages 638-647
    Published: December 20, 2021
    Released on J-STAGE: December 20, 2021
    JOURNAL RESTRICTED ACCESS

    The present study investigates a new adsorbent for Cs(I) removal from green tea extract. An extract of green tea rich in polyphenolic compounds was simply cross-linked using concentrated sulfuric acid to reduce aqueous solubility and improve Cs(I) adsorption. Dissolution of total organic carbon (TOC) from non-modified tea extract (TE, 4,324 mg/L) was drastically suppressed in cross-linked tea extract (CLTE, 13.6 mg/L). The adsorption performance of CLTE for Cs(I) was compared with TE, the feed material, using the batch-wise method. Kinetic study showed that the adsorption equilibrium can be reached within 4 h for native TE and 12 h for CLTE. The maximum adsorption capacity of Cs(I) using non-modified tea extract (TE, 0.20 mmol/g) was drastically increased after cross-linking (CLTE, 1.23 mmol/g). The Cs(I) ion was selectively adsorbed onto CLTE from a mixture containing a trace amount of Cs(I) and a high concentration of Na(I). Therefore, the CLTE adsorbent investigated in this study can be expected to be a potential efficient; and environmentally benign adsorbent for the treatment of water polluted with Cs(I) ion.

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Chemical Reaction Engineering
  • Gakuto Kato, Hayato Doi, Hidenori Ohashi, Hideaki Tokuyama
    Article type: Research Paper
    2021 Volume 54 Issue 12 Pages 648-656
    Published: December 20, 2021
    Released on J-STAGE: December 20, 2021
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    Au(0) nanoparticles catalyze many reactions and various Au-polymer composites have been developed to date. Herein, we developed different types of Au(0)-nanoparticle-loaded gels and investigated the effects of their structural features such as the polymer type, gel diameter, and gel composition on their catalytic properties. N-isopropylacrylamide (NIPA) gel, N,N-dimethylacrylamide (DMAA) gel, poly(ethylene glycol) diacrylate (PEGDA) gel, and poly(ethylene glycol) methyl ether acrylate (PEGMEA) gel were used, and millimeter-, micrometer-, and nanometer-sized gels were fabricated. Au(0)-nanoparticle-loaded gels were obtained by adsorbing Au(III) ions onto the gels, followed by the reduction of the adsorbed ions. All the Au(0)-nanoparticle-loaded gels successfully functioned as catalysts for the reduction of p-nitrophenol to p-aminophenol with NaBH4. The catalytic performance of the gels was evaluated using the pseudo-first-order reaction rate constant and apparent activation energy. The polymer type and the DMAA gel composition had little effect on the apparent reaction rate constant. The kinetic rate-determining steps in the Au(0)-nanoparticle-loaded gels with various diameters were identified using the Weisz–Prater modulus and the effectiveness factor, and the concentration profile of the reactant in the gels were estimated.

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Process Systems Engineering and Safety
  • Dan Wang, Jie-Sheng Wang, Shao-Yan Wang, Cheng Xing
    Article type: Research Paper
    2021 Volume 54 Issue 12 Pages 657-671
    Published: December 20, 2021
    Released on J-STAGE: December 20, 2021
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    Simulated moving bed (SMB) chromatographic separation technology is a new type of separation technology developed on the basis of traditional fixed bed adsorption operation and real moving bed (TMB) chromatographic separation technology. The component purity of the extract and raffinate during the SMB chromatographic separation was used as the prediction object. An adaptive soft-sensing modeling method for SMB chromatographic separation process based on dynamic fuzzy neural network (D-FNN) and moving window strategy. Dynamic fuzzy neural network soft-sensing models based on Kalman filter (KF) algorithm, linear least squares (LLS) method, and extended Kalman filter (EKF) method. The moving window strategy is then adopted to realize the adaptive revision on the soft-sensing model, and the prediction performances are with compared with the soft-sensing model established by the generalized dynamic fuzzy neural network (GD-FNN). The simulation results show that the proposed soft-sensing model can not only effectively achieve accurate prediction of key economic and technical indicators of the SMB chromatographic separation process, but also meat the real-time, efficient, and robust operation of the SMB chromatographic separation process.

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  • Shigeki Ootakara, Yoshiyuki Yamashita
    Article type: Research Paper
    2021 Volume 54 Issue 12 Pages 672-684
    Published: December 20, 2021
    Released on J-STAGE: December 20, 2021
    JOURNAL RESTRICTED ACCESS

    We present a model identification method for a self-excited oscillatory process, which uses only the time series data of oscillation and PID parameters. This method is applicable to cases where the self-excited oscillation is caused by unsuitable PID parameters. The models being identified include an integral system and a first-order delay system with dead time. Because system identification experiments are not required, the method can be applied to any historical operation data if the PID parameters are known. Additionally, the PID control parameter design for the integral system proposed in the previous study is extended to a first-order delay system. The new proposed method is applied to a vinyl acetate monomer (VAM) process simulator. Closed-loop identification of nine PID control loops with self-excited oscillations is performed, and the plant operation is stabilized at once without retuning using the obtained PID parameters.

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