CONCEPTUAL OPTIMIZATION OF UTILITY NETWORKS FOR OPERATIONAL VARIATIONS - I - TARGETS AND LEVEL OPTIMIZATION

The design of utility networks involves two major tasks: the selection of the steam levels, with respect to their pressure or saturation tem perature, and the determination of the configuration of the operating units between the steam levels. Both tasks require models that enable the conversion of the cogeneration potential into shaftwork targets, o n the basis of which the profitability of the proposed designs is deci ded. This paper introduces a new targeting model and procedures to ana lyse existing design options ahead of design. The turbine hardware mod el (THM) accounts for the variation of efficiency with the turbine siz e, load and operating conditions in a simple, yet accurate way. The mo del is derived by exploiting basic steam turbine principles and engine ering knowledge. It is applicable to any type of units and can provide accurate estimates of its performance over the entire operation range . As such, it can be used for setting realistic targets for shaftwork at the early stages of design, as well as for selecting the steam leve ls that maximise the potential for power cogeneration. The application of the THM is illustrated through a number of examples involving simp le and multiple operations, and a comparison is made with a constant e fficiency model. (C) 1998 Elsevier Science Ltd. All rights reserved.