الفهرس 
Heat Recovery Steam Generator (HRSG)Only 14 pages are availabe for public view
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Abstract
The combined-cycle unit combines the Brayton (gas turbine) and Rankin (steam turbine) thermodynamic cycles by using heat recovery boilers to capture the energy in the gas turbine exhaust gases for steam production to supply a steam turbine as shown in the figure ”Combined- Cycle Cogeneration Unit”. Process steam can be also provided for industrial purposes. Fossil fuel-fired (central) power plants use either steam or combustion turbines to provide the mechanical power to electrical generators. Pressurized high temperature steam or gas expands through various stages of a turbine, transferring energy to the rotating turbine blades. The turbine is mechanically coupled to a generator, which produces electricity. The gas/steam combined cycle has already become a well-proven and important technology for power generation due to its numerous advantages. The advantages include its high efficiency in utilizing energy resources, low environmental emissions, short duration of construction, low initial investment cost, low operation and maintenance cost, and flexibility in fuel selection .