Study on the Microwave Heating Fe3O4 Fixed-Bed Process for Dichloromethane Treatment

• Main Authors: Yao-Ting Shen, 沈耀庭
• Other Authors: Bing-Nan Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/94841533676074969830

碩士 === 大仁科技大學 === 環境管理研究所 === 93 === This research was undertaken to investigate the treatment of a simulated industrial flue gas containing of dichloromethane over a Fe3O4 packed-bed under microwave radiation field. It was observed that the Fe3O4 packed-bed can be heated by microwave radiation quickly up to a temperature above 900℃, which is much higher than the flammable temperature of most volatile organic compounds (VOCs). The Voss in the influent gas were nearly decomposed and no black smoke was generated during the microwave treatment process. Experimental results revealed that microwave technology allowed the treatment of industrial flue gas to meet the more stringently discharging limit by the regulation. Based on the experiment data, temperature of the Fe3O4 packed-bed could reach a steady state after having been heated by microwave radiation for 10±1 min and temperatures measured at point E (Zi/L = 0.5) and point M (Zi/L = 0.9) were 555±12℃ and 980±30℃, respectively. Furthermore, the destruction removal efficiency (DRE) was calculated more than 99.99% during the following heating process. The higher concentration of dichloromethane (DCM) in the influent gas, the greater heating rate of the Fe3O4 packed-bed was measured, as a result of heat release from the reaction of DCM being burned. It was found that heating rate of the Fe3O4 packed-bed was 86.54℃ min－1 with a DCM concentration of 2000 ppmv, however, the heating rate was lower (71.38℃ min－1) if DCM concentration was as low as in concentration of 500 ppmv. Effect of space velocity (SV) of the influent gas over the microwave treatment process was found insignificant (p = 0.832). Despite an increasing SV of the influent gas was increased from 1572 hr－1 to 5240 hr－1, the decreased DRE of DCM was found only 1.31%. In addition, addition of acetone (ACE) in concentration of 260 ppmv into the flue gas, consisting of DCM in 2000 pomp, could increase the DRE of DCM as a result of increasing temperature of the Fe3O4 packed-bed about 25±6℃. Though addition of hexane (HEX) in 650 ppmv could inhibit the oxidation of DCM and result a decrease 7.81％ of DRE of DCM in the flue gas during the first 5 min microwave radiation heating period, more than 99.99% of DRE of DCM was found in a spite of ACE or HEX addition into the flue gas when the heating process was lasting for more than 11 min. Experimental results of this research revealed that it is promising technology to treat a flue gas consist of VOCs in concentrations less than 2000 ppmv by microwave radiation heating on Fe3O4 packed-bed process.