以觸媒分解氣相中萘之研究

Decomposition of Naphthalene Using Catalyst in Gas Phase

陳家豪(Jia-Hao Chen)

指導教授 ： 張慶源

國立臺灣大學/工學院/環境工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01275

摘要

本研究主要是以萘作為氣相中多環芳香族碳氫化合物(polynuclear aromatic hydrocarbons, PAHs)之指標物種，利用觸媒焚化與臭氧氧化程序處理加以去除。研究中改變不同操作參數如：反應溫度、觸媒粒徑、空間速度及臭氧濃度，探討萘在不同操作條件下之處理效率，並建立觸媒反應動力模式以描述去除萘之動力行為。研究結果顯示萘在經過觸媒分解後，會加快反應速率，且溫度在480 K、空間速度為35,000 hr-1以下時，去除效率幾乎可達到95%以上。另外反應溫度、觸媒粒徑及空間速度三種影響因子中，以反應溫度對萘轉化率之影響程度最大。在產物分析方面，CO2為觸媒分解萘之主要產氣，由礦化率計算之結果可得知，當萘轉化率到達95%以上，溫度505 K時，礦化率可達92%以上，相較之下萘幾乎被完全分解而轉化成二氧化碳。由反應動力模式之推求結果，顯示Rideal-Eley反應機制與Arrhenius方程式相當適合於描述此觸媒反應系統。此反應速率式可簡化成一階反應，其反應所需之活化能為35.4 kcal/mol，頻率因子為3.26 × 1017 s-1。

關鍵字

動力方程式 ； 觸媒焚化 ； 萘多環芳香族碳氫化合物

並列摘要

The purpose of this study is to investigate the feasibility of the application of the catalytic incineration using Pt/γ-Al2O3 to decompose polycyclic aromatic hydrocarbons (PAHs) (taking naphthalene which is the simplest and least toxic PAH, as a target compound) generated from the waste gaseous stream or diesel engine emission to atmosphere. The relationships between conversion efficiency, operating parameters and influential factors, such as treatment temperatures, catalyst sizes, space velocities and ozone inlet concentrations have been examined. Also, the related kinetic model is proposed to describe the reaction mechanism.
The results indicate that the catalyst of Pt/γ-Al2O3 used accelerates the reaction rate of decomposition of naphthalene, and decreases the reaction temperature. A high conversion (over 95%) can be achieved at the moderate reaction temperature of 480 K and space velocity below 35,000 hr-1. At the same operation condition, the reaction temperature needed is as high as over 1000 K to achieve conversion over 95% for the case without Pt/γ-Al2O3 catalyst. Therefore, the reaction temperature is a determining factor in the catalytic decomposition. CO2 is the major product obtained from the catalytic decomposition of naphthalene. When the conversion of naphthalene is higher than 95%, over 92% mineralization can be achieved at the reaction temperature of 505 K. Also, the results indicate that Rideal-Eley mechanism and Arrhenius equation can be reasonably applied to describe the data by using the pseudo-fist-order reaction kinetic equation. The activation energy (35.4 kcal/mol) and frequency factor (3.26 × 1017 s-1) are obtained therefore.

並列關鍵字

kinetic equation ； PAHs ； naphthalene ； catalytic incineration

參考文獻

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