報告書番号

W03015

タイトル（和文）

燃焼排ガス中揮発性有機化合物の分解触媒の開発 -貴金属担持触媒および酸化物触媒のスクリーニング-

タイトル（英文）

Development of Catalyst for VOC Decomposition in Combustion Flue Gas

概要 （図表や脚注は「報告書全文」に掲載しております）

燃焼排ガス中のVOC（ベンゼン）分解触媒として、酸化物触媒および貴金属担持触媒によるスクリーニングを行った。PdPt担持触媒では水蒸気存在下で分解率は大きく低下したが、空間速度（SV）を12,000h-1から6,000h-1に下げることでPt/Al2O3では98%以上の分解率が得られた。また、SV 12,000h-1においても180℃以上で分解率98%以上を示した。さらに、PdPt/ZrO2CeO2でもSV 12,000h-1、200℃及びSV 6,000h-1、180℃の条件下で分解率98%以上を示し、Pt/Al2O3ともにVOC分解触媒として有望であることを見出した。また、CeO2に関してはSV 6,000h-1、反応温度300℃の条件下でPt/Al2O3と同等の分解率を示し、貴金属担持触媒の代替となるVOC分解触媒として有望であることを見出した。

概要 （英文）

A large number of industrial processes and mobile sources are causing the emission of VOC (Volatile organic compounds) into the atmosphere, thereby contributing to poor air quality. Several VOC are toxic and carcinogenic. Benzene is a known human carcinogenic too. One of the techniques available for decomposition of VOC is catalytic oxidation. The oxide catalyst, multi component oxide and supported noble metal catalyst (Pt/Al2O3, Pd/Al2O3, PdPt/Al2O3, PdPt/ZrO2, PdPt/CeO2, PdPt/ZrO2CeO2) were selected to examine the activity of the catalyst for decomposition of benzene. In the oxide catalyst, CeO2 and ZrO2CeO2 showed about 15% conversion efficiency under the dry gas condition (SV 12,000h-1). However, the conversion efficiency decreased from 15 to 0% over ZrO2CeO2 at reaction time of 60min. On the other hand, Pd/Al2O3, Pt/Al2O3 and supported Pd and Pt catalyst showed above 98% conversion efficiency, but it deactivated by water vapor. The conversion efficiency over Pt/Al2O3 drops from above 98% for dry feed gas to about 80% humidified feed. In contrast, the conversion using supported Pd and Pt catalyst drops from 98% to below 50%. Pt/Al2O3, PdPt/ZrO2CeO2 and PdPt/CeO2 were selected to examine the activity of the catalyst as a function of space velocity (SV 6,000h-1). Catalytic activity was enhanced with a decrease of space velocity. Under these conditions the conversion efficiency was higher than at 12,000h-1. The Pt/Al2O3 was showed above 98% conversion efficiency. The effect of space velocity on the conversion over PdPt/ZrO2CeO2 is similar to that for the PdPt/CeO2. However, it was still below conversion over Pt/Al2O3 at space velocity of 12,000h-1. Next, Pt/Al2O3, PdPt/ZrO2CeO2 and CeO2 were selected to examine the activity of the catalyst as a function of reaction temperature (SV 12,000h-1). The activity of Pt/Al2O3 was significantly greater than that of the PdPt/ZrO2CeO2, especially at lower temperatures. The Pt/Al2O3 showed 98% conversion efficiency at 180℃. In the PdPt/ZrO2CeO2, to achieve approximately above 99% conversion efficiency the temperature had to be increased to 200℃. The above results showed that the Pt/Al2O3, PdPt/ZrO2CeO2 was effective for the decomposition of VOC. On the other hand, CeO2 showed above 98% conversion efficiency at 300℃, space velocity of 6,000h-1. It is noteworthy that even in the presence of humidity the activity of the CeO2 (300℃, SV 6,000h-1) is similar to or exceeds the best attainable activity of the Pt/Al2O3 and PdPt/ZrO2CeO2.

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