tailieunhanh - Dust Explosions in the Process Industries Second Edition phần 8

Thí nghiệm nổ cơn bão tương tự đã được tiến hành ở Nhật Bản gần đây của Hayashi và Matsuda (1988). Bộ máy của họ được minh họa trong hình 6,13. Khối lượng của tàu cơn bão là 0,32 m3, tổng chiều cao 1,8 m và đường kính của hình trụ một phần trên 0,6 m. Những đám mây bụi được thổi vào cơn bão thông qua một ống có đường kính 150 mm. | Sizing of dust explosion vents 453 Similar cyclone explosion experiments were conducted in Japan more recently by Hayashi and Matsuda 1988 . Their apparatus is illustrated in Figure . The volume of the cyclone vessel was m3 its total height m and the diameter of the upper cylindrical part m. Dust clouds were blown into the cyclone through a 150 mm diameter duct. The desired dust concentration was acquired by independent control of the air flow through the duct suction fan at downstream end of system and the dust feeding rate into the air flow. The dust trapped in the cyclone dropped into a m3 dust collecting chamber bolted to the bottom outlet. The exhaust duct of m2 cross section and 3 m length ended in a m3 cubical quenching box fitted with two vents of m2 and m2 respectively. The venting of the cyclone itself was through the m2 X1 Ignition source o P1-P7 Pressure transducers T1-T8 Light-sensing diodes Ig1 Ig2 Ionization probes V1-V2 Explosion venting doors VC1 VC3 Vent covers for methane- air explosion tests Dust chamber Quenching box Figure Experimental cyclone plant for studying dust explosion development under realistic industrial conditions From Hayashi and Matsuda 1988 exhaust duct and the almost 10 m long m2 dust feeding duct. During explosion experiments two water spraying nozzles for flame quenching were in operation in the exhaust duct in order to protect the fan just outside the quenching box. The ignition source was a 5 kJ chemical igniter located in the dust feeding duct about 2 m upstream of the cyclone. Two different polymer dusts were used in the experiments namely an ABS resin dust of median particle size 180 im and an ethylene-vinyl acetate copolymer dust EVA of median particle size 40 . In addition to the realistic dynamic explosion experiments Hayashi and Matsuda 1988 conducted a series of experiments with the same two dusts using an artificial static 454 Dust Explosions in the .