考虑产汽的延迟焦化装置分馏与换热过程集成优化

Integrated Optimization of the Fractionation and Heat Exchange Processes in Delayed Coker With Considering Steam Generation

分馏、换热过程和公用工程三者的整体集成对于延迟焦化装置的用能优化极为关键。在分馏与换热过程的集成中,考虑以复杂分馏塔的取热作为关键耦合变量,建立基于换热网络分级超结构的集成优化模型(混合整数非线性模型)。从理论上探讨通过发生不同等级的蒸汽进一步强化热量回收,优化装置的产汽等级和产汽量,从而提高装置的整体用能效率和经济效益。在案例研究中,对3个优化层次,即不考虑产汽、考虑产汽的孤立优化和考虑产汽的多系统集成的结果进行对比。结果表明,考虑产汽的孤立优化、考虑产汽的多系统集成这两个优化层次比不考虑产汽优化层次的年度总费用分别降低0.2×106 RMB/a和3.2×106 RMB/a,考虑产汽的集成优化结果更优。模型可揭示和辨识不同过程间的相互作用关系。

In the energy optimization of delayed coker, fractionation, heat exchange and utility are the key points. During the integration between fractionation and heat exchange, integrated optimization model （mixed integer nonlinear programming model） was established based on stage wise superstructure of heat exchanger networks, taking heat removals from the complex fractionator as key coupling variables. To strengthen the energy recovery through steam generation, the steam levels and flow rates were optimized theoretically, thus the whole energy efficiency was gradually improved as well as economic benefit. Results of three optimization levels were compared in the case study. Compared with the first optimization level, the annual total costs of the latter two optimization levels decreased by 0.2 ×10^6 and 3.2 ×10^6 RMB/a, respectively, indicating that it is superior to consider steam generation in integrated optimization. Besides, the integrated optimization model can reveal and identify the interaction among different processes.