ES precept 2

Pagina 1

Precept 2: Mass/energy balances of a Steam Cycle Mechanical Engineering - Energy Systems Authors: •Group xx: xxxxx xxxxx (xxxxxxxx), F abio Santoro (xxxxxxxx) Lecturer:Prof. Stef ano Consonni T eaching Assistants:Riccardo Cremona, Hamidreza Heydari and Nima Razmjoo Academic year:2025-2026 Contents Description 2 1 Thermodynamic conditions 4 2 Mass Flow Rates 10 3 Relevant performances 10 4 RegeneratorrbT− ˙Qdiagram 11 5 Results 13 References 13 1 Energy Systems - Report Precept 2 - Group xx Description This precept covers the design of a Rankine steam cycle plant, where the input thermal power is provided by a firing boiler using the combustion of natural gas, as represented in the scheme of Figure 1 on page 3. All the relevant data are collected in Table 1 on page 4. Let us briefly describe the combustion process: the ambient air(a)is preheated in the Ljungstrom heat exchanger by the hot flue gases to state(b). At this point, the preheated air(b)is mixed with the fuel(h)in the combustion chamber(c), where the combustion reaction takes place. The resulting hot flue gases evaporate the water to state(d)and then heat the steam in the superheater and reheater to state(e). Finally, the flue gases preheat the feedwater to near-saturation conditions at state(f)and warm the inlet air in the Ljungstrom heat exchanger before exiting the boiler at state (g)to go to the stack. The plant is a subcritical Rankine steam plant, where electrical power is generated by the rotation of three turbines operating at different pressure levels (high, intermediate, and low). The three turbines are mounted on the same shaft, which is connected to the alternator. Thesteamgeneratedintheboilerbytheeconomizer(eco), theevaporator(ev a), andthesuperheater (sh)enters the first turbine(hp)under…