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Department of Energy Politecnico di Milano Author Pag.1 of 12 Date 24/06/2020 Milan, 06th June 2020 Exam – Advanced Thermodynamic and Thermoeconomics 15-06-2020 Exercise 1. Let’s consider an innovative biomass -fed steam cycle. The thermal energy required by the steam cycle to generate the steam is provided by a dedicated combustion chamber supplied by biomass feedstock. Biomass is pre-treated (PT) by reducing water content and increasing the temperature thanks to a contribution coming from the combustion chamber (stream 4) at steady conditions. The combustion chamber (CC) takes in input the pre-treated feedstock (stream 1), ambient air (stream 2) and produces useful heat for the steam cycle ( Q̇ boiler) at 2000 K. Flue gases (stream 3) are then treated before being given off by means of a flue gases treatment (FGT) system which investment costs are reported in Table 2. The steam cycle gets in input the heat required to vaporize water. Th e condenser of the steam cycle discharges Q̇ cond to the environment. Consider that the water coming from the turbine enters into the condenser at 44°C and exits at 42°C. The overall work produced by the steam cycle is Ẇ net. Consider that T0 and P0 are respectively: 298 K and 1 atm. Abbreviations: PT – pre-treatment; CC – combustion chamber; FGT – flue gases treatment; SC – steam cycle. Table 1 State Exergy [MW] 0 Input feedstock 100 1 Treated feedstock 105 2 Ambient air 0 3 Treated flue gases 18 4 Treatment heat 15 Quantity Energy [MW] Q̇ boiler 80 Q̇ cond 40 Ẇ net Net power 45 Table 2 Unit cost of feedstock [€/MWh] 20 Z – PT (Investment, O&M) [€/h] 50 Z – CC (Investment, O&M) [€/h] 150 Z – SC (Investment, O&M) [€/h] 1000 Z – FGT (Investment, O&M) [€/h] 350 FIGURE 1. PLANT CONFIGURATION pre-treatment combustion chamber Steam cycle…