Tham khảo tài liệu 'advanced gas turbine cycles episode 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | y turbine cycles OVERALL EFFICIENCY PRESSURE RATIO Ref. 151 . Chapter 6. Wet gas turbine plants 99 Combined STIG Steam Air Fig. . Combined STIG plant after Frutschi and Plancherel 1 . . The combined STIG cycle The combined STIG cycle Fig. was described by Frutschi and Plancherel 1 . Steam is raised at two pressure levels in the waste heat boiler. Superheated steam at the higher pressure level expands through a steam turbine before injection into the compressor discharge air stream. Low pressure steam is injected STIG fashion into the combustion chamber. Attainable efficiency for this plant may in theory reach about 50 . In a variation of this combined cycle the Foster-Pegg plant the steam turbine drives a second high pressure compressor. . The FAST cycle Another modification of the combined STIG cycle is the so-called advanced steam topping FAST cycle. Now the double steam injection process before and after combustion of the combined STIG cycle of Fig. is replaced by a single steam injection into the combustion chamber after expansion in the steam turbine and reheating in the HRSG Fig. . In one version the steam turbine and the gas turbine are on the same shaft jointly driving the electrical generator. To call this cycle a steam topping cycle is somewhat misleading since it is essentially a doubly open combined cycle in that heat rejection from the upper gas turbine is rejected to a lower main steam turbine cycle. This lower cycle now includes reheating steam leaving the steam turbine being reheated before a second expansion in the gas turbine. But of course the steam is exhausted with the gas and is not finally condensed and there is no recirculation of water. . Developments of the EGT cycle There have been a larger number of proposals for recuperated cycles with water injection and evaporation but all these can be interpreted as modifications of the EGT plant which is essentially a wet CBTX cycle as explained above. Advanced
