摘要

Because of the strong coupling between the prefractionator and the main distillation column involved, the dividing-wall distillation column (DWDC) may exhibit the so-called black-hole problem in the operating range of interest when four product compositions (i.e., the main compositions in the three products and the ratio between the two impurities in the intermediate product) have been specified. In this paper, a novel strategy is proposed to solve the black-hole problem by the arrangements of multiple intermediate products to the main distillation column of the DWDC. The number, locations, and flow rates of the multiple intermediate products are designated as decision variables to coordinate the relationship between the prefractionator and the main distillation column involved, and a simple procedure is developed for the determination of their values effectively. The separations of two ternary mixtures of hypothetical components, A, B, and C and ethanol, propanol, and butanol, are chosen as illustrative examples to evaluate the feasibility and effectiveness of the proposed strategy. In terms of steady-state analysis and dynamic operation studies, it is demonstrated that the black-hole problem can be completely circumvented by the arrangements of multiple intermediate products to the DWDC. The proposed strategy is considered to be of general significance and can be applicable and effective to the synthesis and design of the DWDC separating ternary mixtures with widely different thermodynamic properties.

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