Abstract A recent paper explored the separation of the close-boiling mixture 1,2 propanediol (PDO) and ethylene glycol (EG). The optimum operating pressure using a traditional single vessel was 282 kPa with a reboiler duty of 399 kW. However, the vapor–liquid equilibrium shifts with pressure such that higher pressure is favorable in the PDO-rich region. An interesting steady-state design was developed that splits the column into a high-pressure rectifier (4.9 bar) and a low-pressure stripper (2.38 bar). A compressor (32 kW) moves vapor from the top of the stripper into the bottom of the rectifier. The hot vapor leaving the top of the rectifier at 244 °C provides all the heat required in the reboiler at the base of the stripper (234 °C). This novel design reduces energy cost by 85%. An effective control structure for this complex process is developed in this paper. A small auxiliary reboiler and condenser are used to stabilize the system and to handle large disturbances in throughput and feed composition.

中文翻译：

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二压蒸馏塔的控制

摘要 最近的一篇论文探讨了接近沸点的混合物 1,2 丙二醇 (PDO) 和乙二醇 (EG) 的分离。使用传统单容器的最佳操作压力为 282 kPa，再沸器负荷为 399 kW。然而，气液平衡随压力而变化，因此在富含 PDO 的区域中更高的压力是有利的。开发了一种有趣的稳态设计，将塔分成高压精馏塔 (4.9 bar) 和低压汽提塔 (2.38 bar)。一台压缩机 (32 kW) 将蒸汽从汽提塔顶部移动到精馏塔底部。离开精馏塔顶部的 244 °C 热蒸汽提供汽提塔底部再沸器所需的所有热量 (234 °C)。这种新颖的设计将能源成本降低了 85%。本文针对这一复杂过程开发了一种有效的控制结构。小型辅助再沸器和冷凝器用于稳定系统并处理吞吐量和进料成分的大扰动。