A Study on the Electrification and Neutralization Process of Powders during Piping Transportation

[[abstract]]由於在工業製程中以顆粒狀物料或粉體作為原物料的製程作業日益增加，在物料輸送過程中，輸送物料和管路均會產生靜電，形成潛在危害源。現今對於靜電的產生與逸散尚未完全掌控及量化。若輸送作業的環境中存有易燃易爆物質，當環境達爆炸下限時，靜電有一定機率成為點火源而發生火災爆炸事故。本研究以實驗裝置模擬物料傳輸作業，實驗流速、流量、濕度、不同物料對管路及物料帶電之影響、若輸送管路設有彎管時，彎管的帶電特性和使物料通過一金屬接地導體，實驗金屬接地導體對消除輸送物料帶電之有效性。以提供靜電產生特性與消除方法的基本相關數據為本研究之目的。 實驗結果得知，管路的帶電電位與輸送的流速越快、流量越高，管路的帶電越高。環境濕度越高，管路的帶電越低。在相同的管路中輸送不同物料，管路的帶電電位也會不同。在良導體的不鏽鋼管及碳鋼管中輸送丙烯腈-丁二烯-苯乙烯聚合物顆粒和粉末(ABS顆粒、ABS粉末)及耐燃級-丙烯腈-丁二烯-苯乙烯聚合物(FR-ABS顆粒)，直管和彎管的電位幾乎相同。絕緣體的塑膠管，彎管的帶電電位最高，其次為彎管入口和直管。顆粒物料和粉體物料的帶電電位會因濕度高低所影響。輸送顆粒物料的流速越快，顆粒的電位有上升的趨勢。而粉體的電位有下降的趨勢。輸送顆粒物料的流量越高，顆粒的電位有下降的趨勢。顆粒物料、和粉體通過金屬接地網的電位與未通過金屬接地網的電位無明顯差異。ABS粉末在不鏽鋼管中輸送通過金屬接地網的電位皆小於未通過的電位，而在碳鋼管和塑膠管中輸送，則無明顯差異。[[abstract]]In this study the purposes were experiments to the surfaces of the horizontal straight pipe and the curved pipes (the stainless steel the carbon steel and the PVC) powders (the Flame Retardant Acrylonitrile-Butadiene-Styrene Copolymer particles and the Acrylonitrile-Butadiene-Styrene Copolymer particles and powders) static electrification characteristics and method of powders static neutralization in powders pneumatic transportation apparatus From the results of the experiments the increase in transportation velocity and transportation flow will increased the pipe’s electric potential In the stainless steel pipes and the carbon steel pipes which transported the particles and powders of the electric potential of the horizontal straight pipe and the curved pipe did not show any significant differences In the PVC pipes the curved pipes generated a higher electric potential than the horizontal straight pipe and the electric potential was 50 to 100 times higher than the stainless steel pipe and the carbon steel pipe In the same PVC pipes which transported the FR-ABS particles and ABS particles will generated different electric potentials The increase in transportation velocity that might lead to the increase of the particles electric potential but as a result the powders were decreased The increased in transportation flow that might lead to a decrease in the particles electric potential Also the increase in equilibrium relative humidity that lead to decrease of the pipes particles and powders electric potential The electric potential of the particles and powders were not significant shown in the passing of the grounding of metal grids and did not pass the ground of the metal grid