Improved Short-Term Batch Scheduling Flexibility Using Variable Recipes

Abstract

Batch scheduling and control decision levels are usually optimized separately, even though integrated decisions would potentially increase the overall performance of the plant. This work aims at including in the scheduling problem the operating conditions related to the control function, which are traditionally optimized and fixed beforehand, to shed light to the benefits that may be obtained when using variable recipes in contrast to fixed nominal recipes. A multiproduct and a multipurpose plant illustrate the proposed approach. In both cases, the potential benefits are confirmed resulting in clear advantages regarding overall economic benefit, when the variable recipes are introduced. Thus, the presented approach gives rise to new tradeoffs, since it allows new improvement opportunities associated with quality, safety, or changing operating policies, which are usually considered separately.

110th Anniversary: Using Data to Bridge the Time and Length Scales of Process Systems

“…A conceptual depiction of flexible-recipe and aggregate surrogate models is presented in Figure . In the former, a data set consisting of feasible operating points is used to generate a simple data-driven model of the processing times and costs of a batch unit. , In the latter, the scheduling layer and process dynamics are represented in a combined surrogate model. The use of data naturally takes a key role for both approaches, but it is worth noting that the aggregate approach would likely require quite significant amounts of data to capture the vast range of process behaviors that can arise when considering both production scheduling and process control.…”

From time representation in scheduling to the solution of strip packing problems

“…They are thus more appropriate for integration with the lower level control layer (Capón-Garcia et al 2011). Deciding for a continuous-time model needs to be followed by the choice of the concept used to keep track of events taking place.…”

Novel Optimization Model and Efficient Solution Method for Integrating Dynamic Optimization with Process Operations of Continuous Manufacturing Processes

“…Planning, scheduling, and dynamic optimization of chemical processes are highly interconnected. − The aim of planning is to determine the production assignment of manufacturing processes over a long time horizon. In each planning period, scheduling is used to determine the detailed production sequence, task assignment, processing time, resource allocation, etc.…”