Targeting cogeneration and waste utilization through process integration

In this paper we focus on energy flows and specifically on the complex interactions between heat and power generation and use in steam systems along with combustible wastes of the process. Our objective is to present a systematic methodology for the quick targeting of power cogeneration potential in steam systems ahead of designing the power generation network. The devised approach makes effective utilization of combustible wastes and reconciles the use and dispatch of process fuel sources, heating and non-heating uses of steam, and power generation. The new concept of extractable energy is introduced to facilitate a simple calculation of cogeneration potential in the process. Balances around steam headers are used to identify surpluses and deficits. Next, surplus and deficit composite curves are constructed to identify feasible transfers of extractable energy. The result is the identification of the cogeneration target and excess steam that can be used in condensing turbines. This methodology takes a holistic view of the process and can easily be combined with other mass and energy integration techniques. It specifically accommodates both (a) production objectives (mass integration) and (b) heat recovery network targeting and utility selection (energy integration). An example problem is presented to illustrate the methodology. (C) 2008 Elsevier Ltd. All rights reserved.