Simple removal of dioxins by injecting combustion gas into water

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• 作者：Hirotoshi Kawabata ; Bokka Yabunaka ; Masayuki Tanabe ; Tateo Usui ; Katsukiyo Marukawa ; Shigeta Hara and Toshihiro Tanaka
• 关键词：Simple removal of dioxins ; Exhaust gas ; Gas injection into water ; Incinerators ; Predictive equation
• 刊名：Journal of Material Cycles and Waste Management
• 出版年：2007
• 出版时间：March, 2007
• 年：2007
• 卷：9
• 期：1
• 页码：80-89
• 全文大小：575 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment
  Waste Management and Waste Technology
  Environmental Management
  Industrial Pollution Prevention
  
• 出版者：Springer Japan
• ISSN：1611-8227

文摘

A simple, low-cost method for suppression of dioxins/furans (hereinafter referred to as dioxins) is required because many middle- and, especially, small-scale incinerators have fallen into disuse or have been dismantled because of the high running and system costs of measures for the suppression of dioxins. Therefore, the purpose of the present study was to develop a simple removal method for dioxins from combustion gas and to evaluate the basic removal rate of dioxins. The removal method for suspended matter in a gas mixture (cold model) and dioxins in exhaust gases (hot model) has been investigated by means of gas injection into water, the mechanism of which is that the suspended matter in the gas gathers at the gas–liquid interface. In the cold model, the removal ratio of fine particles (R_P) by gas injection into water was reproduced well by the following equation: R_P (%) = 100 × {1?exp(?0.8?·?S_S?·?t_C)}, where S_S (cm2/cm3) is the specific surface area of bubbles and t_C (s) is the residence time of bubbles in water. The removal ratio of fine particles increased as the product S_s?·?t_C increased. In a hot model using the exhaust gas from combustion experiments of polyvinyl chloride, the removal ratio of dioxins (R_D) by injecting the exhaust gas into water was estimated by the following equation: R_D (%) = 100 × {1?exp(?0.8?·?S_S?·?t_C?·?C_D0 0.07)}, where C_D0 [ng/cm3 (at standard temperature and pressure)] is the dioxins concentration in the exhaust gas before injection into water. R_D depends greatly on the specific surface area of bubbles and the residence time of the bubbles in water, and only weakly on the dioxins concentration in the exhaust gas. Injection of the exhaust gas into water has been shown to be effective and was evaluated as a simple method for the removal of dioxins from exhaust gas.