Shigenobu Hatano

High temperature air-blown woody biomass gasification model for the estimation of an entrained down-flow gasifier

A high temperature air-blown gasification model for woody biomass is developed based on an air-blown gasification experiment. A high temperature air-blown gasification experiment on woody biomass in an entrained down-flow gasifier is carried out, and then the simple gasification model is developed based on the experimental results. In the experiment, air-blown gasification is conducted to demonstrate the behavior of this process. Pulverized wood is used as the gasification fuel, which is injected directly into the entrained down-flow gasifier by the pulverized wood banner. The pulverized wood is sieved through 60 mesh and supplied at rates of 19 and 27kg/h. The oxygen-carbon molar ratio (O/C) is employed as the operational condition instead of the air ratio. The maximum temperature achievable is over 1400K when the O/C is from 1.26 to 1.84. The results show that the gas composition is followed by the CO-shift reaction equilibrium. Therefore, the air-blown gasification model is developed based on the CO-shift reaction equilibrium. The simple gasification model agrees well with the experimental results. From calculations in large-scale units, the cold gas is able to achieve 80% efficiency in the air-blown gasification, when the woody biomass feedrate is over 1000kg/h and input air temperature is 700K.

Drying Enhancement of Clay Slab by Microwave Heating

ABSTRACT The effect of internal heating by microwave on the drying behavior of a slab was studied. A wet sample of kaolin pressed into a slab was subjected in microwave irradiation of 2.45 GHz. The absorption of microwave energy into a wet slab can be expressed by a function of the moisture content and the pathway length, which is a similar form to Lambert-Beers law. The drying behavior was compared among three modes: microwave irradiation, hot air heating and radiation heating in an oven. Microwave heating with a constant power resulted in breaking the sample when the internal temperature achieves at 373 K. However, if the power was controlled to maintain the temperature less than the boiling point of water, the drying succeeded without any crack generation until the completion with a significantly faster drying rate than in convective heating or in the oven. It is also noted that the transient behavior of the temperature is quite different from the conventional drying.

Effect of Scattering by Fluidization of Electrically Conductive Beads on Electrical Field Intensity Profile in Microwave Dryers

Abstract: A technology to apply a fluidized bed of electrically conductive beads is proposed to improve uniformity of the electric field intensity in microwave dryers, which are required for uniform heating of wet media. The principle of this effectiveness lies in a dynamic random scattering of microwave due to motion of the conductive beads in the bed. The electrically conductive beads were prepared by wrapping aluminum foil around styrene foam balls with cellophane tape. The diameter and density were 13 mm and 123 kg/m3, respectively. The minimum fluidizing velocity of these beads agreed with the one predicted by the Wen–Yu equation when the distributor was a porous plate. However, the fluidization of the beads took place at a lower gas rate than the minimum fluidizing velocity due to a jet flow from the small pores for the distributor of a perforate plate. The intensity in the applicator of a commercial microwave oven became the most uniform when the beads were fluidized with a uniform holdup profile along the height of the bed placed in front of the applicator walls. The dynamic effect making the intensity uniform by the fluidization was advanced by increasing the area of apparent reflection by the fluidized bed and the holdup of beads and was superior to a conventional stirring blade.

Development of Process for Manufacturing Metal-Nonmetal Composite Particles Using Fluidized-Bed in Electro-Magnetic Field.

非導電性粒子にてコーティングされた金属粒子を製造するプロセスを開発するために, 電磁場内に設置した流動層を用いて実験を行った.コーティング試験は窒素雰囲気のもとで行った.非導電性粒子を用いる流動層を電磁加熱コイルの中に設置し, 窒素ガスを流し, 電磁場を印加した後に, 所定量の金属粒子を上部より投入し非導電性粒子で被覆された金属粒子を回収した.コーティングの原理は, 非導電性粒子の融点が金属粒子の融点より高いか低いかによって, 2通りあることがわかった.プラスチックによるコーティングについてはプラスチックの融点により, 印加出力, ガス流速の最小点が変化すること, またコーティング厚さは印加出力と共に増加することがわかった.