以選擇性觸媒還原技術同時去除NO及VOCs之效率測試研究

Abstract

利用碳氫化合物為還原劑之選擇性觸媒還原(即Hydrocarbon-Selective Catalytic Reduction, HC-SCR)除硝技術近來逐漸受到重視，但是目前之研究多著重在探討燃料中既有之烷類及烯類等碳氫化合物作為還原劑，若能利用揮發性有機化合物(VOCs)作為還原劑，則可同時處理NOx及VOCs廢氣，進一步擴展HC-SCR之應用領域。研究中選用之VOCs物種包括半導體產業常見之丙酮與異丙醇溶劑，以及汽油中常見之揮發性物質如甲苯等。 本研究利用離子交換法將銅植入HiSiv 3000沸石，並探討溫度、還原劑濃度、觸媒之Cu含量以及空間速度等參數對測試結果之影響。研究結果發現，以銅進行植入改質後之觸媒對於丙酮及NO的去除率明顯優於未經處理之HiSiv 3000沸石，且NO的去除率與觸媒中Cu之含量成正相關。而當丙酮濃度為5000 ppm時，Cu含量達0.563 % 之觸媒對於丙酮的去除率可達95 % 以上，對於NO則有41 % 之處理效率。另一方面，甲苯與異丙醇也被用來測試去除NO及VOC的效能：當甲苯濃度為3000 ppm、NO濃度為500 ppm、空間速度為10000 h-1及溫度為400℃的條件下，NO去除率為33 %；而當IPA濃度為5000 ppm、NO濃度為500 ppm、空間速度為 10000 h-1及溫度為400℃的條件下，NO去除率為29 %。

The Selective Catalytic Reduction with hydrocarbons as the reductants (HC-SCR) has gained increased attention for NOx control. If the volatile organic compounds (VOCs) could be used in HC-SCR, NOx and VOCs might be removed simultaneously. In this study, acetone, isopropyl alcohol (IPA) and toluene are investigated as the HC sources of HC-SCR technology. The copper-coated zeolite was prepared by the ion-exchange method. The effects of parameters such as operation temperature, the concentration of VOCs, the quantity of Cu on the catalysts, and space velocity on the catalyst performance were discussed. The performance of copper-coated zeolite was better than that without Cu on the removals of NO and Acetone. The NO removal efficiency was increased as the quantity of Cu on the zeolite was increased. When the concentration of acetone was 5000 ppm and the zeolite contained 0.563 wt. % of Cu, the removal efficiencies of acetone and NO were over 95 % and 41 %, respectively at a space velocity of 10000 h-1. When the concentrations of toluene and NO were 3000 ppm and 500 ppm, respectively, the NO removal efficiency was 33 % at 400℃. When the concentrations of IPA and NO were 5000 ppm and 500 ppm, respectively, the NO removal efficiency was 29 % at 400℃.