以填充床式放電反應器去除甲苯之最佳操作參數及耗能分析

Abstract

以填充床式非熱電漿技術處理污染物受限於複雜的影響因素如輸入的電壓種類（直流、交流、脈衝）與大小、電極的材質與形式、介電質種類、污染物濃度、攜帶氣體種類、水氣與氧氣含量、氣體流量（停留時間）、溫度等，使此一技術尚未達成熟的階段。 本研究欲建立此一技術最佳化的各操作條件關係，以預測達到預定去除率所需施加的電壓、可控制處理的濃度及流量範圍、消耗的功率及成本效益。評估之操作參數主要以電壓、介電質、污染物濃度與停留時間等四個參數來進行系統化分析。實驗結果顯示反應器消耗功率主要與施加電壓呈正比，其他參數僅小幅度影響消耗功率的變化。最佳操作參數及成本效益之分析評估方法乃是限定一定去除率(90％)，不同參數組合下所能獲得最高成本效益點，即為最佳操作參數。在填充5mm玻璃珠及95％相對溼度下，達到90％去除效率的最佳操作參數值為電壓10.8kV、甲苯進流氣體流量與濃度分別為680cc/min及1000ppm，在此操作點下，反應器之成本效益值為15g/kWh。此一技術就實驗結果證明，以並聯多管反應器方式可以提升處理流量，可去除的進流甲苯氣體濃度範圍相當廣，而且去除效率皆可達到90％以上，足見此一技術深具發展潛力。

The non-thermal plasma technique has not become a mature technique up to the present, based on the complex factors such as input voltage to the reactor, style of electrode and dielectric barrier, inlet concentration of pollutant, carrier gas, contents of oxygen and moisture, retention time and temperature etc. This study intends to establish optimal conditions of operation parameters such as applied voltage, inlet concentration of pollutant, and gas flow rate. The operation parameters were evaluated systematically. The power consumption and the cost-effectiveness for achieving the target decomposition rate are also calculated. The method to evaluate optimal operation parameters and cost-effectiveness is that both the decomposition efficiency and minimum power consumption should be satisfied. The results showed that a packed bed plasma reactor has a higher toluene decomposition efficiency and a lower marginal power consumption cost than the non-packed bed plasma reactor. The toluene decomposition efficiency increases as both the inlet gas flow rate and the toluene gas concentration are decreased. For a plasma reactor of 2 cm in diameter, an over 90% toluene destruction can be reached at a gas flow rate of less than 680 cm3/min, no matter the inlet toluene concentration is high or low. But if the gas flow rate is raised to 1000 cm3/min, then the toluene inlet concentration has to be less than around 500 ppm to achieve high toluene destruction. Under the optimal operation condition, the cost-effectiveness is 15g/kWh. It is also proved that high gas flow rate treatment could be accomplished via multi-tubes reactor.