Dynamic simulation of the multicomponent reactive distillation
Dynamic simulation of the multicomponent reactive distillation
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DOI：
10.1016/0009-2509(96)00226-6
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发表时间：
1996-09
影响因子：
4.7
通讯作者：
K. Alejski;F. Duprat
中科院分区：
文献类型：
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作者：
K. Alejski;F. Duprat
在动力学控制化学反应的情况下，用四个基本假设建立了反应精馏的动态数学模型：与摩尔液含率相比，蒸汽含率可以忽略不计，相的完美混合，通过平板效率修正平衡值，通过“转换效率”修正混合效应的转换。通过与中试精馏塔实际实验结果的比较，验证了不同假设条件下反应精馏动态模拟结果的准确性。同时考虑了系统启动时的非稳态和连续运行时的扰动。以硫酸为均相催化剂，对乙醇与乙酸酯化反应进行了实验研究。当模型中包含关于塔内和再沸器内温度的板的水力描述时，仿真的精度很好。组分浓度的响应精度较低，但施加的干扰很大。所观察到的差异是由于数学模型的简化、高度非理想的多组分系统的动力学和汽液平衡描述的不准确以及瞬态情况下实验测量的精度造成的。与再沸器相比，不同模型下的实验结果与模拟结果的差异最为显著。一般情况下，对反应精馏进行动力学仿真时，应采用考虑平板水力学的描述模型。
A dynamic mathematical model of reactive distillation in case of kinetically controlled chemical reaction is formulated using four basic assumptions: negligible vapour holdup compared to the molar liquid holdup, perfect mixing of phases, corrections of equilibrium values by plate efficiency, corrections of conversion for mixing effects by ‘conversion efficiency’. The accuracy of the dynamic simulation results of reactive distillation obtained under different assumptions is verified by comparing with results of actual experiments on a pilot-scale distillation column. Both the unsteady-state period during start-up and the disturbances of continuous operation are considered. Esterification of ethanol with acetic acid with sulphuric acid as homogeneous catalyst is chosen for experiments. Accuracy of simulation is very good in case of model containing hydraulic description of plates with regard to temperatures inside column and in the reboiler. Responses of component concentrations are less accurate, but imposed disturbances were very large. Observed differences result from simplifications of mathematical model, inaccuracy of the kinetic and vapour-liquid equilibrium description for highly nonideal, multicomponent system and from precision of experimental measurements in case of transient state. Differences between experimental and simulation results in case of different models are the most significant for large holdup on plates in comparison with reboiler. As a general rule, in case of reactive distillation simulation for dynamics, description models taking into consideration plate hydraulics should be used.