一般濕式氧化法(Wet Air Oxidation或WAO)是利用高溫(150℃ ~325 ℃)和高壓(0.5 MPa ~20 MPa)通入氧化劑氣體如空氣或氧氣來熱氧化液相中有機物,高溫的目的在使液相中有機物進行熱分解,高壓是為了使整個熱分解反應會保持在液相中進行,並增加液相溶氧值,以提升氧化分解的效果。 本研究使用半批次式鈦合金高壓(Semi-batch)觸媒濕式氧化反應器以酚水溶液作為處理對象,旨在探討觸媒濕式氧化(CWAO)反應系統中,溫度、壓力及觸媒等條件對於酚水溶液處理效能之影響。 在許多濕式氧化來處理酚水溶液的研究中,貴金屬觸媒如鉑、釕等對於酚的反應具有良好之活性,本實驗中使用貴金屬觸媒鉑、釕、鈀等,負載於氧化鋁擔體上。就單成分觸媒而言中,在溫度160 ℃壓力200 psi下,以2 % Pt/Al2O3觸媒對酚的反應活性較好,另外我們以接續含浸法製作雙成份觸媒(2%Ru/10%CeO2/Al2O3及2%Pt/10% CeO2 /Al2O3)探討加入氧化鈰之雙成份觸媒對酚水溶液的處理效能有無活性加成之作用。 觸媒的分析是用程溫還原(TPR)來觀察觸媒先驅體的還原情形,並使用CO化學吸附求得Ru的分散度。 最後就動力學的部分,以酚水溶液氧化的實驗數據配合Arrhenius Equation,推得酚反應之反應速率常數及活化能,其酚水溶液濕式氧化的反應假設為一階反應。
Catalytic wet oxidation (CWO) is a liquid-phase reaction between organic material in water and oxygen. The CWO process is used to treat industrial wastewater at moderate temperature (150-325℃) , and at pressures from 0.5 to 20 MPa. High pressures are employed not to keep the water in liquid phase but to increase dissolved oxygen concentration as well. Studies on catalytic wet oxidation of phenol in aqueous solution have been studied by using a semi-batch reactor. The affect of temperature, pressure and catalysts was investigated. In present works, employment of noble metal catalysts such as Pt, Ru and Pd show good activity for treating phenol in aqueous solution. Experimental results show 2%Pt/Al2O3 catalyst exhibits the best activity at 160℃ and 200 psig. Addition of CeO2 to the noble metal catalysts was also implemented by sequential impregnation to find the interaction between Ru, Pt and CeO2 enhances the catalyst activity for the wet oxidation of phenol. Reaction properties of catalyst precursors were analyzed by temperature programmed reduction. In addition, CO chemisorption was used to determine the dispersion of Ru metal clusters. Arrhenius equation was applied to account form the observed characteristics of experimental data. By assuming the reaction rate obeys the first-order with respect to the concentration of phenol under the pressure of 200 psig. We can find the values of activation energy and frequency factor.