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首页> 外文期刊>Environmental Science & Technology >Methanol Oxidation Using Ozone on Titania-Supported Vanadia Catalyst
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Methanol Oxidation Using Ozone on Titania-Supported Vanadia Catalyst

机译：二氧化钛负载的钒催化剂上使用臭氧进行甲醇氧化

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Ozone-enhanced catalytic oxidation of methanol has been conducted at mild temperatures of 100-250℃ using a V_2O_5/ TiO_2 catalyst prepared by the sol-gel method. The catalyst was characterized using XRD, surface area measurements, and temperature-programmed desorption of methanol. The oxidation of methanol with ozone in the absence of a catalyst gave about 30% conversion at 100℃. Methanol oxidation over a V_2O_5/TiO_2 catalyst at 100℃ gave very little conversion with oxygen, whereas the conversion increased to 80% with ozone. Methanol, having an inlet stream concentration of 15 000 ppmv, can be completely oxidized to CO_x with an ozone-to-methanol ratio of 1.2, a temperature of 150℃, and a gas hourly space velocity (GHSV) of 60 000 h~(-1). The apparent activation energy with ozone was calculated to be ca. 40 kJ/mol, which is much lower than that calculated with oxygen (60 kJ/mol). At low methanol conversion methyl formate was the main product, whereas higher conversions favored oxidation to CO_x. The results imply a consecutive reaction of adsorbed methanol species, favoring selectivity toward methyl formate at lower temperatures and ozone-to-methanol ratios and CO_x at highertemperatures and ozone-to-methanol ratios. Langmuir-Hinshelwood kinetics was used to model the reaction with and without ozone in the feed. The model parameters were obtained using least-squares fit to a selected set of experimental data, and the model was subsequently compared to all experimental data obtained in this study.
机译：使用溶胶-凝胶法制备的V_2O_5 / TiO_2催化剂在100-250℃的温和温度下进行了臭氧增强的甲醇催化氧化反应。使用XRD，表面积测量和程序升温的甲醇脱附对催化剂进行了表征。在没有催化剂的情况下用臭氧将甲醇氧化，在100℃时约有30％的转化率。在100℃下，V_2O_5 / TiO_2催化剂上的甲醇氧化反应几乎没有氧气转化率，而臭氧转化率提高到80％。入口物流浓度为15000 ppmv的甲醇可以被完全氧化为CO_x，其臭氧与​​甲醇的比例为1.2，温度为150℃，气体时空速（GHSV）为60 000 h〜（ -1）。计算出的与臭氧的表观活化能约为。 40 kJ / mol，比用氧气计算的结果（60 kJ / mol）低得多。在低甲醇转化率下，甲酸甲酯是主要产物，而较高的转化率有利于氧化成CO_x。结果暗示被吸附的甲醇物质的连续反应，有利于在较低温度和臭氧与甲醇的比率下对甲酸甲酯的选择性以及在较高温度和臭氧与甲醇的比率下对CO_x的选择性。 Langmuir-Hinshelwood动力学用于模拟进料中是否有臭氧的反应。使用与选定的一组实验数据拟合的最小二乘法获得模型参数，然后将模型与本研究中获得的所有实验数据进行比较。

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