Pilot burners are miniature gas burners installed in, or close to, the main burner to provide a small proven flame as the ignition source for the principle fuel(s). Prior to igniting the pilot burner the combustion chamber must first be purged with air to minimise the risk of a flammable vapor being present.

Conventional pilot burners and their associated ignition systems can be unreliable. This can often be traced to failure of the spark ignitor, incorrect air / gas ratio or poor flame detection.

The principle causes of these problems are:

• Narrow air / gas ratio limits
• Poor design of the ignition electrodes
• Wet plant air
• Optical flame scanners incorrectly sighted or obscured by dust etc.
• Poor design and fragile construction of pilot

The FCT High Performance Pilot consists of a gas supply tube within an outer air tube. The business end of the pilot has three stabilising gas jets and a main raw gas jet. Enough air to ensure stabilisation of the pilot flame is supplied down the air tube. The stabilising gas jets discharge gas within the perforated gas distributor, which ensures the gas mixes with the stabilising air and produces a wide range gas / air mixtures within the stabilising region. Hence some part of this region is always within the flammable limits providing very good flame stability. Ignition is by high tension spark, high energy spark or flame front.

Conventional kiln burner ignition systems can be unreliable. The principle cause of these problems are the long, fragile ignition electrodes (often up to 45 ft long) associated with rotary kiln burners. These electrodes are vulnerable to electrical short circuit and, once this occurs, the igniter fails and the burner cannot be lit.

The FCT flame front ignition system overcomes these and offers the following benefits:

• Rugged durable design
• No long electrodes - easily accessible spark plug used.
• Simple, reliable, easily maintained flame detection system.
• Suitable for use with many types of pilot burner.
• In service with pulverised coal, oil, gas and multi-fuel burners.
• Simple to operate and maintain.
• Safe for use by operators without supervision.
• Proven in service over ten years on more than 50 rotary kilns world-wide.

The Flame Front igniter consists of a tube mounted alongside the pilot burner with a spark plug at the end (outside the burner), see illustration below. Flame detection is by flame ionisation using a short robust electrode connected to a high temperature (1600 C) flexible cable. The Flame Front ignition system is supplied complete with its own valve train and control system. This allows the operator to initiate the automatic sequence by simply pressing a button.

Pulverised coal fired kilns require an auxiliary fuel for start up in order to raise the temperature until the coal firing can be self sustaining. Usually a special oil burner is used. A wide firing range is required to ensure a controlled warm-up of the kiln refractory.

FCT offer a range of oil fired kiln warm-up burners which feature an advanced twin fluid atomiser. This atomiser has been specially designed for kiln warm-up purposes and features a common mixing chamber to minimise the risk of jet blockages.

A turn down ratio of at least 8:1 is achieved and thus the complete kiln warm-up can be undertaken without the need to stop and change atomizers.

FCT kiln start-up burners are equipped with the unique flame front ignition system.