Spark ignition at the flare pilot nozzle is simple and easy to automate and has therefore become wide spread. With these systems the spark generation must be located somewhere near the pilot tip where it will be exposed to the flammable mixture that exits the tip.
In some cases, the life of the sparking device may be shortened due to continuous exposure to the pilot or flare flame once ignition is established. This can be a problem because neither the flare pilot nor its igniter assembly can be replaced while the flare is in operation.
Retractable systems are offered by some vendors in order to tackle this issue, however experience shows that such arrangements rarely remain operational for long following commissioning due to deformation caused by radiated heat and flare flame impingement.
There are two basic forms of electronic ignition system, high energy and high voltage. The high energy systems operate at lower voltages using a capacitor to deliver a high-energy spark as insulation breaks down at voltages in the region of 600 volts. The high voltage systems rely on several thousand volt discharges causing a spark across an air gap to light the pilot. Such systems require specialised high tension cable that is more susceptible to breakdown when subjected to excessive heat. The weak part of this system has always been the connection into the pilot burner. Argo’s recommended electronic igntion system is the High Energy (HE) type, however we can offer replacement pilots for existing HT systems.
Overall spark igniters of this category rely on the location of the igniter within the pilot burner. Damage to the pilot heads by heat or direct flame impingement will often render the system inoperative, and without the opportunity for service between major shutdown, results in a system reliability of between 2 and 5 years. Together with Argo’s pilot and ignition system improvement we recommend the use of Alloy 556 pilot nozzles to extend pilot lifetime.