内部热耦合中间隔壁塔的设计与控制

Design and control of an internally heat integrated middle dividing wall column

虽然隔离壁精馏塔(DWC)与多个常规精馏塔组成的常规分离序列相比具有明显的节能潜力,但是通过引入内部热耦合技术,仍然具有进一步强化设计的空间。以进料位置为界,可将DWC分为上、下两部分,上部包含公共精馏段和进料上端的隔离壁两侧,下部包含进料下端的隔离壁两侧和公共提馏段,在两部分之间设置内部热耦合,得到一种新型内部热耦合中间隔壁塔(IHIMDWC)。在进料上、下两端的隔离壁一侧或两侧设置内部热耦合可以得到4种不同的IHIMDWC拓扑结构。以甲醇、乙醇与正丙醇三元物系的分离为例,通过启发式搜索法对4种IHIMDWC拓扑结构进行稳态设计,并提出了一种分散温度控制系统以验证它们的可控性。仿真结果表明,与DWC相比,IHIMDWC不但可以显著降低能量消耗,而且所设计的分散温度控制系统可以有效地抑制干扰。

Although a dividing wall column (DWC) is more energy-efficient than the conventional distillation sequence composed of multiple conventional distillation columns, it can still be further intensified. The DWC can be divided into upper and lower parts in terms of the feed location (the upper part includes the common rectifying section and the two sections adjacent to the partition above the feed location, whilst the lower part contains the two sections adjacent to the partition under the feed location and the common stripping section). A novel internally heat integrated middle dividing wall column (IHIMDWC) has been developed by introducing internal heat integration between the two parts. Depending on the arrangement of the internal heat integration at one side or both sides of the partition above or under the feed location, four topological configurations can be derived. Taking the separation of a ternary mixture of methanol, ethanol and 1-propanol as an illustrative example, these four topological configurations were optimized by a heuristic search method and their controllability was examined using a decentralized temperature control system. The simulation results show that the IHIMDWC can not only reduce energy consumption when compared with the DWC, but the proposed decentralized temperature control system can also effectively suppress disturbances.