In the operation of power-intensive Air Separation Units (ASUs) that produce storable liquid products, optimization opportunities exist at two time scales − week-ahead production scheduling to leverage fluctuations in electricity prices, and real-time decisions that optimize the entire plant operation and capture spot opportunities. In our previous work, we proposed a methodology based on flexibility analysis and robust optimization to ensure feasibility of real-time operational decisions at ASUs for future time periods within a scheduling horizon. In this paper, we build upon the methodology to propose approaches to improve the online performance of a production schedule for ASUs by using the real-time optimization layer. We compare several policies for real-time optimization and our studies on real plant data show interesting trade-offs between week-ahead scheduling and real-time optimization.

在生产可存储液体产品的高功率空气分离装置（ASU）的运行中，存在两个时间尺度上的优化机会-提前一周进行生产调度以利用电价的波动，以及实时决策来优化整个工厂的运行并抓住机会。在我们以前的工作中，我们提出了一种基于灵活性分析和鲁棒优化的方法，以确保在ASU上针对调度范围内的未来时间段进行实时操作决策的可行性。在本文中，我们基于该方法论，提出了通过使用实时优化层来提高ASU生产计划的在线性能的方法。