Potential of ORC Systems to Retrofit CHP Plants in Wastewater Treatment Stations

摘要: Wastewater treatment stations take advantage of the biogas produced from sludge in anaerobic digesters to generate electricity (reciprocating gas engines) and heat (cooling water engine exhaust gases). A fraction this is used operate plant while remaining sold grid. Heat almost entirely support endothermic digestion a minimum it rejected environment at set fan coolers. This generic description applicable on-design conditions. Nevertheless, operating conditions present large seasonal variation so commonly found that atmosphere increases significantly certain times year. Moreover, available gases reciprocating very high temperature (around 650 oC), which far needed for 40 oC digesters). difference offers an opportunity introduce intermediate system between engines makes use convert into electricity. An Organic Rankine Cycle (ORC) with appropriate working fluid adequate candidate these hot/cold sources. In paper, techno-economic effect adding as existing wastewater station analysed. On purpose, different fluids layouts have been studied reference giving rise optimal systems configurations. The proposed yield promising results regard global efficiency production (thermodynamically economically).