Yield and selectivity analysis of a bubble flow using the example of toluene oxidation

泡状流的产率和选择性受反应网络动力学、传质、两相流宏观混合以及泡尾流微观混合的影响。为了以合理的精度预测反应性气泡群中的产率和产物选择性，所涉及的机制的速率应该从单独的、独立的研究中确定。通过实验或数值计算确定的参数被输入到双流模型中，以确定在主要条件下的产品形成。在此背景下，ICVT正在计划以下特定项目。i）用自由基链机理确定技术合成的宏观动力学，而不受可能的质量传输限制的影响。建立了均相条件并成功操作。由于进行了敏感性分析，因此难以评价测量结果。需要进一步改进。开发的动力学将提供给AK Rzehak和AK Hlawitschka，用于后续模型验证。一旦可用，AK Rinke的便携式拉曼探针将被测试用于在线分析。ii）用于验证预测泡罩流中的产率和选择性的计算方法的实验该研究所有一个泡罩塔可用，其将在升高的压力和温度下操作。在外围调整后，将测量AK Schindler的反应性[Fe 2（HPTB）Cl 3]模型系统，然后进行甲苯氧化。（3）混合物对气泡尺度对产物选择性影响的研究混合过程对气泡尺度的影响只能在宏观模拟中以动力学“修正”的形式考虑。为了评估对产物选择性的影响，将开发简化模型。其目的是调查的条件下，这些都是必要的，并根据情况，开发一个简化的计算方法，允许的混合物上的气泡尺度的影响被集成到宏观计算。我们正在与AK Marschall合作，比较简化和详细的模拟。此外，还同意就方法问题与AK Hampel / Kryk进行深入交流。

Yield and selectivity of a bubbly flow are influenced by the kinetic of the reaction network, the mass transport, the macroscopic mixing of a two-phase flow as well as the microscopic mix-ing in the bubble wake. To predict yield and product selectivities in a reactive bubble swarm with reasonable accuracy the rates of the involved mechanisms should be determined from separate, independent studies. The parameter determined by experiments or numerical cal-culations are input to a two-flow model to determine the product formation under the prevailing conditions.Within that context the ICVT is planning the following particular projects.i) The determination of a macroscopic kinetics for a technical synthesis with a radical chain mechanism without influence of a possible mass transport limitationIn the ongoing project phase a kinetic apparatus for measurement under homogeneous con-ditions was set up and successfully operated. The evaluation of the measurement was diffi-cult due to the susceptible analysis. Further improvements are required. The developed ki-netics is to be made available to AK Rzehak and AK Hlawitschka for a later model validation. Once available, a portable Raman probe from the AK Rinke is to be tested for online analysis.ii) Experiments for validation of the calculation methodology for the prediction of yield and selectivity in a bubble flowThe institute has a bubble column available which is to be operated at elevated pressure and temperatures. After an adaptation of the periphery, the reactive [Fe2(HPTB)Cl3]-model sys-tem of the AK Schindler is to be measured, followed by the toluene oxidation. The measure-ments are used to validate the calculation methodology in AK Rhezak and AK Hlawitschka.iii) Studies on the influence of the mixture on the bubble scale on the product selectiv-itiesThe influence of the mixing processes on the bubble scale can only be considered in macro-scopic simulations in the form of correlations to the "corrections" of the kinetics. In order to assess the influence on product selectivity, a simplified model is to be developed. The aim is to investigate the conditions under which these are necessary and, as the case may be, to develop a simplified calculation methodology which allows the effects of the mixture on the bubble scale to be integrated into the macroscopic calculation. We are cooperating here with the AK Marschall to compare simplified and detailed simulations. Furthermore, an intensive exchange concerning the methodology with the AK Hampel / Kryk has been agreed to.