Abstract
This work presents a new method for integrating various renewable energy feedstock sources with the utility systems of combined heat and power generation hubs and heat exchanger networks (HENs). The combined heat and power hub of the integrated network involves two turbines fed with high pressure steam. The steam can be generated from fuel sources such as wood, corn stover, and glycerine. The power system is required to produce a fixed amount of shaft power while optimally satisfying the hot utility demand of the HEN of a process plant through the high-pressure steam and intermediate pressure steams exiting the turbines. The superstructure of the integrated system comprises three layers and is synthesised using the utility hub approach. The first layer of the superstructure, which comprises the feedstock supply chain network, is modelled as a mixed integer linear program. The second layer of the superstructure, which comprises the combined heat and power hub wherein are the steam system and turbines for the power plant, is modelled using linear program to represent the material and energy balances of the turbine system. The third layer, which comprises a HEN, is modelled using the simplified stagewise superstructure (SWS) synthesis approach. The objective function of the integrated model comprises operating costs, capital costs, and environmental impact. The newly developed method is applied to a case study using the weighted method of multi-objective optimisation and the results obtained involves the selection of corn stover and glycerine for the generation of heat and power. Also, only high-pressure steam and medium pressure steam were selected for use as hot utilities in the integrated HEN of the system.