Gas turbines are now ubiquitous as the source of electrical energy in most power plants. Gas turbines are easier to start and they are cheaper to operate than coal-fueled plants. To understand how the gas turbine works, you need to get more insight into the combustion process and how it is initiated. If you are thinking of a source of energy for your plant, it is important to get this insight before investing in a gas turbine. There are a few facts to help you understand the combustion process like spark plugs and flame detectors.
Role of Spark Plugs
There are two high-voltage and non-retractable spark plugs in a gas turbine and they are firmly bolted to the combustion chambers with mounting on the primary zone cup in adjacent combustors. These sparks initiate combustion and they receive their energy from ignition transformers. For combustion to start, a spark at one of the plugs or on both will ignite the present gases in the primary zone area of the chamber. The gases in the rest of the chambers are ignited by crossfire, which is made possible through tubes interconnecting reaction zones in each of these chambers.
The Importance of Flame Detectors
Just like in a vehicle, it is important for the person in control to know whether there is a flame during this starting sequence. The control system needs to be alerted in order to understand whether there is a problem or the system is working optimally. A flame monitoring system is thus important for a gas turbine; this system features eight sensors with two sensors in each of four combustion chambers (10 & 11 primary and secondary zone, n° 4 and 5). An electronic amplifier is also mounted in the control panel.
The ultraviolet flame sensor contains a gas filled detector, which is sensitive to presence of UV radiation which is one of the byproducts of a hydrocarbon flame. The presence of a flame indicates the gas in the detector is ionized allowing condition in the circuit and activating the electronics to announce presence of a flame. Absence of a flame will also give a ‘no flame’ output but if a flame is reestablished, a signal is sent to a replay panel to fire trip circuit or starting the circuit.
A flame detection system is crucial for a gas turbine and it is important to invest in a professional technician to inspect the system if you realize there is an issue. This could be a matter of life and death.