Framework methodology for increased energy efficiency and renewable feedstock integration in industrial clusters

Paper in proceeding, 2012

Energy intensive industries, such as the bulk chemical industry, are facing major challenges. The chemical cluster in Stenungsund on the West coast of Sweden recently adopted a common vision called “Sustainable Chemistry 2030”. The cluster consists of 5 different companies operating 6 process plants. There is a wide range of technologies and process integration opportunities available for improving the clusters overall performance, including (i) decreasing fossil fuel and electricity demand by increasing heat integration within individual processes and across the total site; (ii) replacing fossil feedstocks with renewables and biorefinery integration with the existing cluster; (iii) increased external utilization of excess process heat wherever possible. This paper presents an overview of the use of process integration methods for the holistic development of the cluster. The framework methodology is based on a Total Site Analysis (TSA) study, in which the cluster’s current energy system was analysed and measures for site-wide energy efficiency improvement were identified. TSA showed that up to 129 MW of heat can be recovered by site-wide energy efficiency measures, theoretically eliminating the cluster’s demand for external boiler fuel. Pinch analysis of a single plant showed hot utility savings potential of 38 % of the current demand. Heat integration investments with a pay-back period of 0.4 to 1.2 years could cover up to 83 % (6.5 MWheat) of the identified savings potential. A process integration study on replacing fossil based ethylene in the cluster by bio-ethylene produced via fermentation of lignocellulosic biomass and ethanol dehydration showed that the heating demand of the bio-ethylene process can be reduced by 37 % if the both process steps are integrated. TSA showed that 9 MW of excess heat from the cluster can be used to replace hot utility in the biorefinery. A total of 226 MWexcess heat above 50 °C is available from the cluster that can be used, e.g. for district heating, low temperature refrigeration/electricity generation, heat pumping or biomass drying