Takenari Takeshita

Effect of Fluidizing Particle on Drying Characteristics of Porous Materials in Superheated Steam Fluidized Bed under Reduced Pressure

The hygroscopic porous particle was used as the fluidizing particle for the superheated steam fluidized bed drying under reduced pressure. A relatively large material was immersed in the fluidized bed as the drying sample. The drying characteristics of the sample were examined experimentally and the results were compared with those in the case of inert particle fluidized bed. The water transfer from the sample to the fluidizing particle bed in the case of hygroscopic porous particle facilitated the drying regardless of pressure and temperature in the drying chamber. The increment degree of the sample temperature at the earlier period of drying was smaller in the case of hygroscopic porous particle than in the case of inert particle, and the phenomenon was more remarkable in the case of superheated steam than in the case of hot air.

Comparison of three vibrational modes (twist, vertical and horizontal) for fluidization of fine particles

Abstract The effects of three vibrational modes (twist, vertical and horizontal) on flow patterns are discussed. The particles used are four powders (glass beads, 6-100 μm), which are Geldart group A or group C. The fluidity of particles is evaluated with vibration strength (A), minimum fluidization velocity ( u mf ), void fraction and flow patterns in the bed. The effect of vibrational mode on the flow patterns appears in whole bed motion, which is horizontal rotation or vertical rotation caused by twist or horizontal vibrational mode, respectively. For 60 and 100 μm particles, bubble behavior is dominant higher than u mf . Thus, the effects of vibrational mode on the flow patterns in the bed and u mf are not significant. For 30 μm particles, the horizontal rotation or vertical rotation are caused by twist or horizontal vibrational mode, respectively. For 6 μm particles, vertical rotation was not observed. When horizontal vibration is added to the bed, the lower limit of gas velocity for channel breakage for 6 μm is the lowest among the three vibrational modes. It is considered that the horizontal vibration affects channel breakage as the shear force.

Effect of aeration rate on flow rate of granular materials from a hopper attaching a standpipe

Abstract Air was injected close to the standpipe inlet to control the particle flow rate from a hopper, and the relationships between the particle flow rate, the aeration rate, the particle diameter and the hopper angle were examined. A semi-theoretical method is presented to calculate the aeration rate at the point where discharge stops. Using the calculated aeration rate, an estimation method for the mass flow rate of a granular material with air injection is also presented, and compared with the experimental results.

Experimental and Modeling Study on CO2 Absorption in a Cyclone Scrubber by Phenomenological Model and Neural Networks

Experimental and modeling studies have been conducted on CO2 absorption in a cyclone scrubber operated at room temperature. The effects of parameters such as the initial concentration of alkali in the solution and the liquid - gas ratio on the CO2 absorbed flux were experimentally and theoretically investigated. A phenomenological model and three-layer feed-forward neural networks have been applied to estimate the CO2 absorbed flux in the cyclone scrubber. It was shown that the neural networks’ values agreed well with the experimental data, while the values by phenomenological model partly agreed with the experimental data around the initial concentration of alkali in the solution, CBo≤0.001 kmol/m3 (pH≤11).

control of flow rate of granular materials from a hopper with a standpipe by aeration.

ホッパー排出端に取り付けたスタンドパイプの上部から吹き込む空気量が多いほど粒子排出量は減少するので, この吹き込み空気量を調整することによって粒子排出量を制御できることがわかった.また, 排出する粒子径が小さいほど少ない空気量で粒子排出量を制御できた.ホッパーから排出される粒子の流路は, スタンドパイプ上部で収縮し縮流となるが, 下降するにつれ再び膨張する.これを考慮した実験式を用いて, ホッパーおよびスタンドパイプ内の粒子と空気の物質収支式と運動方程式を解くと, ±30%の精度で粒子排出量を推算できた.また, 定常流動時の内部空気圧分布の推算値は実測値とよく一致した.