Design and control for recycle plants with heat-integrated separators
Design and control for recycle plants with heat-integrated separators
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DOI：
10.1016/j.ces.2003.09.019
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发表时间：
2004-01-01
影响因子：
4.7
通讯作者：
Yu, CC
中科院分区：
文献类型：
--
作者：
Lin, SW;Yu, CC
这项工作分析了稳态经济学与热集成回收厂的动态可控性之间的权衡。该过程由Tyreus和Luyben首先研究的一个反应堆，两个蒸馏柱和两个回收流组成（Ind。Eng。Chem。Sres。32（1993）1154），并由Cheng and Yu进一步探索（A.I.Ch.e. J. 49（A.I.Ch.e. 49）（ 2003）682），在这项工作中，两个蒸馏柱进行了热集成。设计问题与典型的列测序和热积分设计不同，因为我们可以设计反应堆组成。分析了具有直接和间接序列的热积聚植物的最佳轨迹，随着C（Z（c））的反应器组成而分析。在任何给定的z（c）上都有正确的热积分方向，为两个序列建立了流程。事实证明，在整个Z（c）的整个范围内，具有直接序列的热积聚植物在经济上是最佳的。对于动态可控性，可及的生产范围被确定为回收比（回收流量/生产率）变化。结果表明，随着热量整合程度的增加，稳态可控性逐渐恶化，并且在50％节能线上，我们失去了一个控制自由度。但是，如果回收厂是最佳设计的（z（c）近似于0.6），则观察到可接受的转换比，并且稳态经济学和动态可操作性之间的折衷很少。最后，使用严格的非线性模拟来测试不同过程配置的控制性能（有和没有热积分）。结果表明，可以为精心设计的热集成回收植物（与没有能量整合的植物相比）来实现改善的控制。更重要的是，通过节省多达40％的节能，可以实现更好的性能，并节省近20％的年度成本。 （c）2003 Elsevier Ltd.保留所有权利。
This work analyzes the tradeoff between steady-state economics and dynamic controllability for heat-integrated recycle plants. The process consists of one reactor, two distillation columns, and two recycle streams first studied by Tyreus and Luyben (Ind. Eng. Chem. Res. 32 (1993) 1154) and further explored by Cheng and Yu (A.I.Ch.E. J. 49 (2003) 682) and, in this work, the two distillation columns are heat integrated. The design problem differs from typical column sequencing and heat-integration design, because we can design the reactor composition. Optimal trajectories for heat-integrated recycle plants with direct and indirect sequences are analyzed as the reactor composition of C (z(C)) varies. Provided with correct direction for heat integration, at any given z(C), the flowsheet is established for both sequences. It turns out the heat-integrated recycle plant with direct sequence is economically optimal throughout the entire range of Z(C). For dynamic controllability, the reachable production range is identified as the recycle ratios (recycle flow rate/production rate) vary. Results show that the steady-state controllability deteriorates gradually as the degree of heat integration increases and, to the extreme, at the 50% energy saving line, we have lost one control degree of freedom. However, if the recycle plant is optimally designed (z(C) approximate to 0.6), acceptable turndown ratio is observed and little tradeoff between steady-state economics and dynamic operability may result. Finally, rigorous nonlinear simulations are used to test control performance of different process configurations (with and without heat integration). The results reveal that improved control can be achieved for well-designed heat-integrated recycle plants (compared to the plants without energy integration). More importantly, better performance is achieved with up to 40% energy saving and close to 20% saving in total annual cost. (C) 2003 Elsevier Ltd. All rights reserved.