The long-term planning problem for integrated gas field development is investigated. The key decisions involve both design of the production and transportation network structure and operation of the gas fields over time. A novel continuous-time modeling and optimization approach is proposed, which introduces the concept of event points and allows the well platforms to come online at potentially...

Varicol is a continuous chromatographic separation process which is based on the simulated moving bed principle with an asynchronous commutation of the inlet and outlet streams. The objective of this work is to develop a systematic procedure to optimize the operating conditions of the Varicol process, including the commutation sequence and the internal flow rates. To this end, the continuous dy...

Abstract:This paper addresses the short-term scheduling problem for the ethylene cracking process with feedstocks and energy constraints. The cracking production of ethylene is a process with units that have decaying performance, requiring periodic cleanup to restore their performance. Under the condition of limited feedstocks, the production operating mode of the cracking furnaces is to keep y...

This paper addresses the synthesis and optimization of crystallization processes for pxylene recovery for systems with feed streams of high concentration, a case that arises in hybrid designs where the first step is commonly performed by adsorption. A novel superstructure and its corresponding mixed-integer nonlinear programming (MINLP) model are proposed. The distinct feature of this superstru...

The rigorous and efficient determination of the global solution of a nonconvex MINLP problem arising from product portfolio optimization introduced by Kallrath (2003) is addressed. The objective of the optimization problem is to determine the optimal number and capacity of reactors satisfying the demand and leading to a minimal total cost. Based on the model developed by Kallrath (2003), an imp...

This paper studies the multi-stage supply chain system (MSSCM) controlled by the kanban mechanism. In the kanban system, decision making is based on the number of kanbans as well as batch sizes. A kanban mechanism is employed to assist in linking different production processes in a supply chain system in order to implement the scope of just-in-time (JIT) philosophy. For a MSSCM, a mixed-integer...

A penalty framework for globally solving mixed-integer nonlinear programming problems is presented. Both integrality constraints and nonlinear constraints are handled separately by hyperbolic tangent penalty functions. The preliminary numerical experiments show that the proposed penalty approach is effective and the hyperbolic tangent penalties compete with other popular penalties.