Chemical and refinery process operations have to deal with an increasingly transient and competitive marketplace. The traditional strategy of operating a plant in isolation from its environment within and outside the supply chain, where exogenous influences are interpreted and handled as disturbances, is not any more appropriate. Rather, manufacturing must quickly adapt to the transient environment to exploit economical potentials to the degree possible. At least, the traditional plant focussed operational strategy must account for the dynamics in the disturbances by employing predictions of their future time-varying behavior in real-time optimization to result in an intentionally dynamic operational strategy. Further, plant performance can be significantly improved, if knowledge on the status and on the future policies and goals of some partners in the supply chain can be employed for plant optimization. Such a cooperative mode of interaction in the supply chain will lead from plant focussed to supply chain conscious, often intentionally dynamic plant operation. Advanced concepts are identified and discussed, a number of relevant research issues are suggested. Keywords

In this article steady-state multiplicity analysis is used to provide guidelines to assess the operability of jacketed diabatic stirred tank reactors. Previous work is extended to include nth order kinetics, multiple compartments on the cooling jacket and a variable heat transfer coefficient. Bifurcation theory is used to determine design parameter changes that move hysteresis and limit points to extreme values of the input variable (jacket flowrate), causing the formation of infeasible temperature regions. In addition we show the connection between the bifurcation conditions and traditional multiplicity analysis involving intersections of the steady-state heat generation and removal rate curves. 2 1 Introduction It has been realized for a long period of time that it is important to consider the operability and controllability of chemical processes at the design stage. A number of relevant techniques have been proposed, including flexibility analysis (Grossman and Morari, 1984), resi...

Process design is usually approached by considering the steady-state performance of the process based on an economic objective. Only after the process design is determined are the operability aspects of the process considered. This sequential treatment of the process design problem neglects the fact that the dynamic controllability of the process is an inherent property of its design. This work considers a systematic approach where the interaction between the steady-state design and the dynamic controllability is analyzed by simultaneously considering both economic and controllability criteria. This method follows a process synthesis approach where a process superstructure is used to represent the set of structural alternatives. This superstructure is modeled mathematically by a set of differential and algebraic equations which contains both continuous and integer variables. Two objectives representing the steady-state design and dynamic controllability of the process are considered. T...