Home | Contact Us

Gas Turbine Power Plant - Page 2/2

►Gas Turbines (Open Cycle):

The modern power gas turbine is a high-technology package that is comprised of a compressor, combustor, power turbine, and generator, as shown in the figure "Simple-Cycle Gas Turbine".

In a gas turbine, large volumes of air are compressed to high pressure in a multistage compressor for distribution to one or more combustion gases from the combustion chambers power an axial turbine that drives the compressor and the generator before exhausting to atmosphere. In this way, the combustion gases in a gas turbine power the turbine directly, rather than requiring heat
transfer to a water/steam cycle to power a steam turbine, as in the steam plant. The latest gas turbine designs use turbine inlet temperatures of 1,500C (2,730F) and compression ratios as high as 30:1 (for aeroderivatives) giving thermal efficiencies of 35 percent or more for a simple-cycle gas turbine.

Gas Combined Cycle:

The combined-cycle unit combines the Rankine (steam turbine) and Brayton (gas 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.

Gas Combined Cycle

Jet engines:

Gas turbines for electrical power production

Industrial gas turbines range in size from truck-mounted mobile plants to enormous, complex systems. They can be particularly efficient up to 60% when waste heat from the gas turbine is recovered by a conventional steam turbine in a combined cycle configuration. They can also be run in a cogeneration configuration, where the exhaust is captured to heat steam which is then used to heat buildings or to run air conditioners through a steam turbine.

Simple cycle gas turbines in the power industry require smaller capital investment than combined cycle gas, coal or nuclear plants and can be designed to generate small or large amounts of power. Also, the actual construction process can take as little as several weeks to a few months, compared to years for baseload plants. Their other main advantage is the ability to be turned on and off within minutes, supplying power during peak demand. Large simple cycle gas turbines may produce several hundred megawatts of power and approach 40 % thermal efficiency.