Novel Multiple Time-grid Continuous-time Mathematical Formulation for Short-term Scheduling of Multipurpose Batch Plants

Abstract

In this work, we have developed two novel unit-specific event-based mixed-integer linear programing models for scheduling multipurpose batch plants. The concept of indirect and direct material transfer is introduced to rigorously sequence and align tasks in different units. A batch after production is allowed to be partially transferred to storage and downstream processing units or held in processing units over multiple event points. The computational results demonstrate that the proposed models require a smaller number of event points in many cases to achieve optimality than existing unit-specific event-based models. It is interesting to find that no task is required to span over multiple event points to reach optimality for all addressed examples. The best variant developed is superior to existing unit-specific event-based models with the same or better objective values by a maximum improvement of 67%. The computational effort is significantly reduced by at least 1 order of magnitude in some cases.

Integrating Continuous and Batch Processes with Shared Resources in Closed-Loop Scheduling: A Case Study on Tuna Cannery

“…The logical conjunction between variables X i, g and Y g, k (the relation cart to retort) is linearized by the following inequalities: (8) (9) (10) Using such Z i, k variables, the paths allowed from production lines to retorts are modeled by (11) Next, some relations describing the time constraints of the assignment will be presented. The starting time of every sterilization cycle is bounded by the carts included in its slot g, i.e., it has to start before the food product in the cart with the shorter waiting-time gap θ i in the group g is unsafe, but never before all carts to be grouped in such slot have been released from the sealing lines.…”

“…of a particular application with enough accuracy. Note that, in addition to the advances in computational power and optimization solvers, important research has been conducted during the last years to improve the performance of scheduling DSS, both from the modeling and solution strategies. , …”

Introducing the I&ECR Virtual Collection of Industrial and Industrially Relevant Research (2022–2023)

“…Although most studies in Process Systems Engineering come from academic groups, the topic area is very important to industrial researchers, with papers in the collection including an August 2023 cover article on the impact of H 2 /N 2 ratio for NH 3 synthesis, a methodology for multipurpose batch plant scheduling, an image-based control method for an agrochemical crystallization process, and a process for preparing propanol from methane …”

“…Here, studies in the collection include a novel methodology of improving polyphenyl sulfide (PPS)-based membranes selected as ACS Editors' Choice in June 2023, 24 an improvement of lubricant oil properties using carbon nanomaterials, 25 synthetic strategies to prepare γ-alumina by coprecipitation (a cover article in January 2023) and FeNi particles by spray pyrolysis, 26,27 the impact of pressure and temperature on sorption of gases by fluoroelastomers, 28 methodologies to improve polymer/clay composite design, 29 novel carbonaceous materials for Li batteries, 30 ripening from a third member of the 2022 Class of Influential Researchers. 31 Although most studies in Process Systems Engineering come from academic groups, the topic area is very important to industrial researchers, with papers in the collection an August 2023 cover article on the impact of H 2 /N 2 ratio for NH 3 synthesis, 32 a methodology for multipurpose batch plant scheduling, 33 an image-based control method for an agrochemical crystallization process, 34 and a process for preparing propanol from methane. 35 The Separations topic area is one where industrial authors demonstrate consistent innovation.…”