In 1979, a mass poisoning occurred in Taiwan from cooking oil contaminated by thermally degraded polychlorinated biphenyls. Because these chemicals persist in human tissue, children born to female patients after the outbreak were exposed in utero. In 1985, 117 children born to affected women and 108 unexposed controls were examined and evaluated. The exposed children were shorter and lighter than controls; they had abnormalities of gingiva, skin, nails, teeth, and lungs more frequently than did controls. The exposed children showed delay of developmental milestones, deficits on formal developmental testing, and abnormalities on behavioral assessment. These findings are most consistent with a generalized disorder of ectodermal tissue. This syndrome is one of very few documented to result from transplacental exposure to pollutant chemicals.

In this paper, the energy-saving potential of an extractive dividing-wall column (EDWC) is investigated. One potential drawback on the EDWC design is that two reboilers in the original design need to be combined into one reboiler. Since a heavy entrainer is used in the extractive distillation system, often cases show that the total reboiler duty is reduced but with adversely increasing the total steam cost. Three industrial separation systems of isopropyl alcohol-water, dimethyl carbonate-methanol, and acetone-methanol have been used as demonstrating examples for critical assessment of the energy-saving potential of the EDWC design. It is found that although the savings of the overall reboiler duty can be made by using the EDWC design, only the acetone-methanol system using water as an entrainer actually saves on the steam cost. The control performance of the EDWC design is also hampered because of losing one important control degree-of-freedom.

In this paper, the energy-saving potential of a heterogeneous azeotropic dividing-wall column is investigated by demonstrating an example for the separation of pyridine and water using toluene as entrainer. The original two-column system includes a heterogeneous azeotropic column with top decanter and another column served as preconcentrator column for the fresh feed and also served as recovery column for aqueous outlet stream from decanter. It is demonstrated that this complex two-column system can be thermally coupled into a dividing-wall column with top decanter. By comparing the optimized design of this dividing-wall column with the original design, a significant reduction (29.48%) in steam cost can be obtained. Furthermore, because important control degree-of-freedoms (two reboiler duties) are still preserved in this dividing-wall column, control performance of this proposed design is found to be comparable to that of the original two-column system.

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