Addressing Robustness in Scheduling Batch Processes with Uncertain Operation Times

Abstract

The uncertainty present in any process environment and related not only to variable market demand but also to operational disturbances is usually unavoidable, and therefore, poor performance may be attained with the execution of deterministic optimal schedules. In this work, the short-term scheduling problem in chemical batch processes with variable processing times is addressed with the aim to identify robust schedules able to face the major effects driving the operation of batch processes with uncertain times, i.e., idle and wait times. The problem is modeled using a two-stage stochastic approach accounting for the minimization of a weighted combination of the expected makespan and the expected wait times. The formulation is extended to explicitly manage risk by optimizing three different robustness criteria. The application of the proposed formulation to academic and industrially based examples shows the efficiency of the proposed approach and highlights the importance of considering the uncertainty in the short-term scheduling level.

Advances in Integrated and Sustainable Supply Chain Planning

“…Otherwise, another well-known approach that is presented as a robust manner of making decisions under uncertainty is to solve the planning problem using stochastic programming Tsiakis et al 2001;Ierapetritou and Pistikopoulos 1996;Bonfill et al 2005). A solution with the optimal expected performance is obtained by including estimated scenarios in the formulation; these estimated scenarios are generated by representing uncertain parameters as random variables (see Appendix A.6).…”

Scheduling With Uncertainty

“…La gestión del riesgo se aborda mediante la adición de una medida de control como un nuevo objetivo a tener en cuenta, lo que conduce a formulaciones de optimización multi-objetivo. En [6], los autores abordaron el problema de programación a corto plazo en procesos por lotes químicos junto con tiempos de procesamiento de variables, para identificar los horarios robustos capaces de enfrentar los principales efectos de conducir la operación de estos procesos con tiempos inciertos, es decir, inactivo, así como los tiempos de espera. El enfoque sobre restricciones de oportunidad, se concentra en la fiabilidad del sistema, es decir, en la capacidad del sistema para satisfacer la viabilidad en un entorno incierto.…”

Addressing the scheduling of chemical supply chains under demand uncertainty

“…The plants of the network are assumed to be multipurpose batch-chemical plants, with a structure adapted from the case study proposed by Kondili et al 35 There is unlimited storage for all the states. The initial inventories are (13,18,13,16,12,17,12,15) supposed to be equal to zero for all the states. Two different types of utilities are considered, the first one, which is associated with the labor tasks, has a cost of 0.25 m.u.…”