Integration of Planning, Scheduling & Closed-loop Optimization/Control
The single most daunting challenge in economic optimization and control of refining units is determining the value of intermediate streams. LP Shadow Prices are notoriously unreliable for use in real-time unit optimization applications. [RPM]™ solves this problem by computing intermediate stream prices which automatically align the unit optimization/control with the schedulers daily orders and the planners period end goals. This innovation allows control engineers to dispense with mode switches for operators to choose in order to achieve desired constraint pushing and produce more profitable solutions that are aligned with planning and the daily orders of scheduling.
[RPM]™ computes the price of every stream that contributes to a product pool at a user set frequency and thus every time a new plan or schedule is published. These prices can be used directly in a unit RTO or an MVCC to consistently drive the RTO or controller on to the constraints desired by the scheduler. The RTO or controller's behavior is automatically synchronized to the goals of planning and scheduling without requiring operator actions to change controller modes. Overcomes the deficiencies of LP shadow prices.
The application reads the market price per unit volume or mass of each product from a user designated location which is usually from the most recent LP solution. In addition it reads the quality price of constrained qualities from a user designated location, typically also the most recent LP solution. The application also calculates the current pool quality, for example for octane, and then calculates the value of each stream contributing to the gasoline pool. The effect of RVP on the value of components is calculated the same way and this calculation is also applied to distillates with respect to the effect of cloud, freeze and flash, depending on which qualitites are constrained.