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What is a combined cycle gas turbine power plant?
12.15.23
ROCHEM Fyrewash Ltd
5-6 Sun Valley Business Park
Winnall Close, Winchester
Hampshire
SO23 0LB
ROCHEM Fyrewash Inc
23707 West Hardy Road
Spring
Texas
77373
12.15.23
We use electricity countless times a day. Right now, the screen you’re reading is powered by it!
But how often do you stop to question how or where your electricity is produced? It’s quite possible a CCGT () can take the credit, but what is a CCGT and how does it work?
Put simply, a CCGT is a power plant with two cycles. Gas is burned to power gas turbine generators which produce electricity.
Then, waste heat from that process is recovered and used to heat water, powering a steam turbine generator which produces more electricity.
The same amount of gas is able to produce far more electricity in this way.
Let’s look at the process step-by-step:
Gas is mixed with air and accelerated through the gas turbine compressor before being fed to the combustion system.
Here, the fuel mix is ignited, creating a high-temperature, high pressure gas stream.
The rapidly expanding gas turns the turbine which spins a generator to produce electricity.
In a regular power plant, that’s pretty much the full story. However, a combined cycle gas turbine puts the waste gas from the first process to good use.
A heat recovery steam generator (HRSG) takes the hot exhaust gas and supplies it to a steam turbine.
The gas is used to heat water, converting it to steam which drives a turbine.
This turbine, much like the one in the first stage, spins a generator to produce additional electricity.
That second cycle makes fantastic use of heat energy which would otherwise go to waste.
Instead of being discharged through the exhaust stack, the energy is converted into electricity with some reporting they produce up to 50% more electricity than a gas turbine alone.
With more electricity generated from the same amount of gas, fuel costs, and greenhouse gas emissions both go down. CCGTs are one way for power plants to .
The main disadvantage of a CCGT is that the initial setup is complex and expensive.
The additional equipment needed for heat recovery and the second cycle of generating electricity is also large and heavy.
If space is limited, it may not be possible to install a combined cycle power plant.
Making use of waste heat seems like a great idea, but you may not be willing or able to convert your gas turbine at this time.
Fortunately, there are ways to ensure you are making the best possible use of the equipment you already have.
Ensuring your gas turbine compressor is kept clean ensures maximum efficiency and lower greenhouse gas emissions.
The equipment and chemicals to facilitate regular washes are a far cheaper alternative to a CCGT upgrade.
At Rochem, we specialise in gas turbine compressor cleaning products.
With over 40 years of experience, we have developed a range of market-leading equipment and which are trusted at sites around the world.
Whether you are responsible for a gas turbine or a combined cycle gas turbine, if you’d like to discuss how we can help.
Post written by Martin Howarth
An extensive knowledge of mechanical and electrical engineering together with hands on experience with gas turbines provides a bedrock for his work at Rochem.