Power plants generate electricity in a number of ways. Two common elements used for power generation are steam and natural gas, each requiring different equipment and operating conditions to maximize performance. Below is a brief guide to the difference between a gas turbine and a steam turbine, listing their key differentiating factors.
Gas turbine
Gas turbines have become important, widespread and reliable devices for power generation, transportation and other applications. A gas turbine is an internal combustion engine that can burn a variety of fuels, which contributes to its versatility.
Gas turbines are the engines at the heart of power plants that generate electricity. Gas turbines are mainly used in gas turbine power plants. According to how a gas turbine works, air is extracted from the atmosphere and then compressed into a compressor. The compressed air then enters the combustion chamber, where it is heated. The hot compressed air then flows over the blades of the gas turbine, imparting rotational motion to the gas turbine. Most of the energy developed by the gas turbine is used to derive the compressor, and the rest is used to do useful work.
Steam turbine
As the name suggests, a steam turbine is powered by the energy in hot gaseous steam and works like a cross between a wind turbine and a water turbine. Steam turbines are designed to transfer energy from a fluid to a rotor that can be used as a generator drive to generate electricity or as a mechanical drive for rotating equipment such as compressors and pumps.
In a steam turbine, high-velocity steam strikes the gas turbine blades. When the steam hits the blades, it spins the turbine's rotor. The generator is connected to the gas turbine, which also starts to spin and generate electricity.
Gas Turbine vs Steam Turbine
The main difference between a gas turbine and a steam turbine is that a steam turbine derives its power from expanding steam. Here we compare some properties between these two properties.
Components
In a gas turbine, the compressor, combustor and power turbine are important components.
In steam turbines, steam boilers and accessories are important components.
Start up
Start-up of a gas turbine is easy and fast.
The start-up of a steam turbine is not easy and takes a long time.
Efficiency
Gas turbines are less efficient.
Steam turbines are very efficient.
Internal temperature
In a gas turbine, the internal temperature reaches 1500 degrees Celsius, which is much higher than that of a steam turbine.
In a steam turbine, the internal temperature reaches only 500 to 650 degrees Celsius, less than half the reaction temperature of a gas turbine.
Installation space
In a gas turbine, less installation space is required.
In steam turbines, more space is required for installation.
Mass production
Less gas turbine mass per kilowatt produced.
Higher quality steam turbines per kilowatt produced.
cost
Gas turbines are less expensive to install and operate.
Steam turbines require higher installation and operating costs.
Control
In a gas turbine, control is easy as load conditions change.
In a steam turbine, control is difficult as load conditions change.
reliance on water supply
Gas turbines do not depend on water supply.
Steam turbines depend on the water supply.
Implement
The gas turbine engine performs the entire Brayton cycle.
A steam turbine is just a component that performs one step of the Rankine cycle.
Working fluid
Gas turbines use air or other gases as the working fluid.
Steam turbines use high pressure steam as the working fluid.
A few things to keep in mind about the difference between a gas turbine and a steam turbine:
The centrality of water means there is a risk of freezing. One of the benefits of a steam turbine is that since water is not the heart of the process, your operation won't be stopped by freezing inside.
Steam turbines are heated using fuels such as natural gas and renewable energy, which can create clean energy if the renewable energy is initially the circulating water that heats the steam turbine. Compared to steam turbines, gas turbines require fossil fuels and the combustion process inherently produces pollutants such as nitrogen oxides.
Unlike gas turbines, steam turbines do not have an air compressor or combustion system, but instead have a boiler, rotors that convert thermal energy into mechanical energy, and the outer shell areas that ensure steam is under pressure in contact with the blades.
Compared to steam turbine power plants, the maintenance cost of gas turbine equipment is lower.
A gas turbine is a combination of compressor, combustor, and turbine that performs cyclic operation to provide work in the form of torque or thrust, while a steam turbine is basically an expander that provides torque as the work output.
