Interpreting the dynamic effect of internal heat integration on reactive distillation columns

In this work, the impact of internal heat integration upon process dynamics and controllability by superposing reactive section onto stripping section, relocating feed locations, and redistributing catalyst within the reactive section is explored based on a hypothetical ideal reactive distillation system containing an exothermic reaction: A + B ↔ C + D. Steady state operation analysis and closed-loop controllability evaluation are carried out by comparing the process designs with and without the consideration of internal heat integration. For superposing reactive section onto stripping section, favorable effect is aroused due to its low sensitivities to the changes in operating condition. For ascending the lower feed stage, somewhat detrimental effect occurs because of the accompanied adverse internal heat integration and strong sensitivity to the changes in operating condition. For descending the upper feed stage, serious detrimental effect happens because of the introduced adverse internal heat integration and strong sensitivity to the changes in operating condition. For redistributing catalyst in the reactive section, fairly small negative influence is aroused by the sensitivity to the changes in operating condition. When reinforcing internal heat integration with a combinatorial use of these three strategies, the decent of the upper feed stage should be avoided in process development. Although the conclusions are derived based on the hypothetical ideal reactive distillation column studied, they are considered to be of general significance to the design and operation of other reactive distillation columns.