RATE EQUATIONS FOR THE CARBON-OXYGEN REACTION : AN EVALUATION OF THE LANGMUIR ADSORPTION ISOTHERM AT ATMOSPHERIC PRESSURE
RATE EQUATIONS FOR THE CARBON-OXYGEN REACTION : AN EVALUATION OF THE LANGMUIR ADSORPTION ISOTHERM AT ATMOSPHERIC PRESSURE
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DOI：
10.1021/ef00025a005
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发表时间：
1991
期刊：
影响因子：
5.3
通讯作者：
R. Essenhigh
中科院分区：
文献类型：
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作者：
R. Essenhigh
根据Davis和Hottel在1934年报道的实验数据，对Langmuir吸附等温线在常压下的碳-氧反应进行了测试，得到了吸附和脱附步骤的活化能和频率因子，E值分别为10.04和32.95 kcal/mol。这些值在两个步骤的预期范围内。评价要求求解O2、N2、CO2四个一维Stefan流的同时扩散方程，通过与实验的比较来检验扩散理论的准确性。Stefan流的Nestening在计算中的系统误差为12%。为了使解与反应性方程结合起来容易处理，它们需要线性化。线性化后的方程用于计算反应碳样品表面的氧浓度，所得数据用于验证朗缪尔速率方程的函数形式。结果表明，该反应为两步反应，一步为吸附，对氧浓度为一级反应，另一步为脱附，为零级反应
The Langmuir adsorption isother has been tested for application to the carbon-oxygen reaction at atmospheric pressure against unique experimental data reported by Davis and Hottel in 1934; and values of activation energy and frequency factor have been obtained for both the adsorption and the desorption steps with E values of 10.04 and 32.95 kcal/mol, respectively. These values are within the expected ranges for the two steps. The evaluation required the solution of the four one-dimensional simultaneous diffusion equations for O 2 , N 2 , CO 2 with Stefan flow, to test the accuracy of the diffusion theory by comparision with experiment. Neglect of the Stefan flow is shown to result in a systematic 12% error in calculation. For the solutions to be tractable in conjunction with the reactivity equations they required linearization. The linearized equations were used to calculate the oxygen concentration at the surface of the reacting carbon samples, and the data obtained were used to validate the functional form of the Langmuir rate equation. The results confirmed in an unambiguous way that the reaction was two step, with one step, identified as adsorption, being first order with respect to oxygen concentration, and the other step, for desorption, being zero order