(715h) Long-Term Maintenance and Production Planning for the Integrated Chemical Enterprise
In order to create a rigorous enterprise production and profitability plan, these factors must be taken into account. They require the tracking of time and production since the previous turnaround, the timing of which is itself a decision variable. Additionally, the large time intervals between routine maintenance turnarounds necessitate very long planning horizons due to end effects, significantly adding to problem size. In this work, an MILP-based framework is presented that includes the above conditions, and, in addition, is able to consider long- and short-term financial performance by providing recommendations that not only maximize long-term NPV, but also balance quarter-to-quarter profits while respecting strict safety requirements and standards. Though profits from sales may be booked soon after delivery, costs for turnarounds are usually incurred several months prior to and several months after execution---this needs to be considered in the formulation when there are quarterly budget constraints or profitability targets.
To summarize, attention to safety, mandatory inspections, production technologies, reliability, maintenance, finance and accounting, and supply chain are all critical to production planning, and we afford these consideration in the current context. Effective reformulations, modeling strategies, and associated case studies are presented to address this real-world large-scale problem.