Flexible process networks

Bok J., Grossmann I.E. and Park S. 2000. Supply chain optimization in continuous flexible process networks, Ind. Eng. Chem. Res., 39, 1279-1290. 

Bok, Grossmann and Park (2000) explained a classification of chemical process networks and characterized them as either dedicated or flexible processes. Dedicated processes operate at one mode and for high volume products whereas flexible processes operate at different modes and produce different products at different times. In the formulation introduced in this chapter, we account for different... 

Sahinidis, N.V. and Grossmann, I.E. (1991b) Multiperiod investment model for processing networks with dedicated and flexible plants. Industrial el Engineering Chemistry Research, 30, 1165. 

Kotjabasakis, E., and Linnhoff, B., Sensitivity tables for the design of flexible processes (1)—How much contingency in heat exchanger networks is cost effective Chem. Eng. Res. Des. 64 (1986). 

Blends with styrenic block copolymers improve the flexibiUty of bitumens and asphalts. The block copolymer content of these blends is usually less than 20% even as Httie as 3% can make significant differences to the properties of asphalt (qv). The block copolymers make the products more flexible, especially at low temperatures, and increase their softening point. They generally decrease the penetration and reduce the tendency to flow at high service temperatures and they also increase the stiffness, tensile strength, ductility, and elastic recovery of the final products. Melt viscosities at processing temperatures remain relatively low so the materials are still easy to apply. As the polymer concentration is increased to about 5%, an interconnected polymer network is formed. At this point the nature of the mixture changes from an asphalt modified by a polymer to a polymer extended with an asphalt. 

The solvent in which the polymer network swelled is able to change the number of intermolecular bonds, to decrease observable flexibility of chain parts between points, and to stretch the system, i.e., to perform labor over it. Its influence on the Qon parameter, according to accepted approximations, is similar to the influence on the process in which only low-molecular compounds participate. Some deviation can be observed as a consequence of suppressing the solvent molecules in the network. One can find that the change of observable local rigidity of the chain as a consequence of network swelling is similar by its first approximation to its change for... 

The processing flexibility of plastic-cellulose networks gives rise to products in various thickness, from a material only a few millimeters thick to structural panels up to several centimeters thick, that include [14] ... 

Instead of a conjunction of preconditions, as used by the STRIPS and conditional operators, the functional operator has a set of conjunctions of preconditions (Fig. 2c). Each element in the set describes some possible situation that might exist before the operator is applied. For each element of the set of preconditions, there is a corresponding element in the set of postconditions. The functional operator is a more flexible model than the STRIPS or conditional operators. It comes closer to the modeling needs for the synthesis of operating procedures for chemical processes, but as we will see in the next section, we need to introduce additional aspects in order to capture the network-like structure of chemical processes. 

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