The kinetics of coke combustion was investigated by using a thermogravimetric analyzer (TGA) of coked catalysts which was used for propane dehydrogenation to determine the activation energy. Apart from the Pt/Al2O3 catalyst, four different Pt-Sn/Al2O3 catalysts were prepared by varying the Pt/Sn ratio from 3: 0.5 to 3: 3 by weight. The catalytic activity was measured by propane dehydrogenation at 620 °C. The reactant mixture consisting of C3H8 (30 ml/min) and H2 (30 ml/min) was fed into the reactor for 5 h. A thermogravimetric analyzer in the presence of air was used to determine the amount of coke deposited and calculate the kinetic parameters for coke combustion. Three non-isothermal models (Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose) were used to determine the activation energy and the best model to fit the experimental data. The FWO model provided the best fit for 3Pt/Al2O3 and 3Pt-0.5Sn/Al2O3. The three models were equivalent for fitting the data for 3Pt-1Sn/Al2O3, 3Pt-2Sn/Al2O3, and 3Pt-3Sn/Al2O3. The activation energy increased with increasing Sn addition in the 3Pt/Al2O3 catalyst. Differences in the locations and the qualitative features of the cokes were suggested to interpret the results.

中文翻译：

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丙烷脱氢废Pt-Sn/Al2O3催化剂的焦炭燃烧动力学

通过使用焦化催化剂的热重分析仪 (TGA) 研究焦炭燃烧的动力学，该催化剂用于丙烷脱氢以确定活化能。除了 Pt/Al2O3 催化剂外，通过将 Pt/Sn 比按重量从 3:0.5 改变到 3:3，制备了四种不同的 Pt-Sn/Al2O3 催化剂。通过在 620°C 下丙烷脱氢测量催化活性。将由C3H8(30ml/min)和H2(30ml/min)组成的反应混合物供入反应器5小时。在空气存在下使用热重分析仪来确定焦炭沉积量并计算焦炭燃烧的动力学参数。三个非等温模型（Friedman、Flynn-Wall-Ozawa (FWO) 和 Kissinger-Akahira-Sunose）用于确定活化能和拟合实验数据的最佳模型。FWO 模型最适合 3Pt/Al2O3 和 3Pt-0.5Sn/Al2O3。这三个模型对于拟合 3Pt-1Sn/Al2O3、3Pt-2Sn/Al2O3 和 3Pt-3Sn/Al2O3 的数据是等效的。活化能随着 3Pt/Al2O3 催化剂中 Sn 添加量的增加而增加。建议使用焦炭的位置和定性特征的差异来解释结果。