精对苯二甲酸尾气中乙酸甲酯低温氧化Pt-Pd双贵金属催化剂的性能

采用浸渍法制备了一系列Pt-Pd双贵金属催化剂,并加入Fe,W,V,Ag,Co,Cu,A1,A10,A11(A1,A10,A11为过渡或稀土金属元素)等金属助剂对催化剂进行改性,考察了助剂、浸渍液的pH、浸渍顺序对催化剂催化氧化乙酸甲酯活性的影响;溴甲烷对催化剂的中毒作用以及CO和水对乙酸甲酯氧化反应的影响。实验结果表明,助剂对乙酸甲酯的氧化反应均有促进作用,其中A1的促进效果尤为显著,Ag的促进作用较弱;浸渍液的pH应小于4,先浸渍Pt-Pd后浸渍金属助剂的双贵金属催化剂活性较高;在Pt-Pd双贵金属催化剂中加入A10和A11助剂后,其抗溴甲烷中毒能力明显提升;模拟尾气中CO对乙酸甲酯的氧化反应有抑制作用,水对氧化反应影响不大,当水和CO同时存在时,催化剂催化乙酸甲酯氧化的能力略有提高。

Properties of Pt-Pd Noble Metal Catalysts in Low Temperature Oxidation of Methyl Acetate from Purified Terephthalic Acid Exhaust Gas

A series of Pt-Pd noble metal catalysts,which could be used in low temperature oxidation of methyl acetate from purified terephthalic acid exhaust gas,were prepared through impregnation.The experimental results showed the catalyst activities for methyl acetate oxidation and the catalyst deactivation by methyl bromide could be improved by adding Fe,W,V,Ag,Co,Cu,A1,A10 and A11(A1,A10,and A11 were transition metals or thulium),especially the A1.Effects of impregnation solution pH and the metal impregnation order on the catalyst activity were investigated.Appropriate impregnation solution pH was less than 4,suitable impregnation order for the catalyst preparation was first impregnation with the noble metals and then impregnation with metal additives.Effects of methyl bromide poisoning,CO and H2O on the methyl acetate catalytic combustion reaction were studied.Anti-poisoning capacities of Pt-Pd catalysts were obviously enhanced after adding A10 and A11.CO existed in the exhaust gas is negative to the catalytic oxidation and effect of H2O is not strong,but when CO and H2O co-existed in the exhaust gas,the catalyst performance for the catalytic oxidation of methyl acetate was slightly heightened.