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Session: Poster Session and Sponsors Exhibition
Session starts: Thursday 22 September, 14:00

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Laura Alonso ()
Joan Carles Bruno ()
Alberto Coronas ()

Abstract:
Cement manufacturing is an energy intensive process, in which a large part of the consumed energy is emitted as waste heat. The BREF reference document [1] reports waste heat recovery for electricity generation as one of the Best Available Techniques for the cement industry. In this paper, integration of two Organic Rankine Cycles (ORC) using two different working fluids is proposed and analyzed. Electricity generation potential of the cycle is very closely related to the availability of the heat source. In the cement manufacturing process two waste heat sources mainly exist: the preheater exhaust and clinker cooler exhaust gases, which have different temperature levels. Energy recovery from both heat sources has been analyzed, considering typical values of exhaust gases flow and temperature. Efficiency of ORC depends mainly on the thermodynamic properties of the working fluid and its operating conditions. Therefore, selection of the working fluid plays a key role in ORC systems, and is determined by the waste heat level. For this particular application, where waste heat at two different temperature levels is available, the use of two Organic Rankine Cycles is analyzed, by using suitable fluids for each heat source. The analysis and comparison of several integrated configurations is presented. Integration of both cycles is optimized in order to maximize heat recovery. The proposed configuration is also compared with a more conventional ORC making use of both waste heat sources but with a single fluid.