Duiker Flame Detector
In general most of the burners which find their application in the sulphur recovery unit (SRU), are furnished with two flame detectors.The goal of these detectors is to monitor continuously whether there is a flame present inside the burner. In the event that the flame would go off , the flame detectors will immediately lose their signal so that the acid gas and air valves in the supply lines can be automatically shut off by the burner management system (BMS). The system is designed to ensure that an essential part of the safety aspect of the SRU plant is met and that risk of explosions is reduced.
We see many different detectors which are applied in the SRU: ultra violet detectors (UV), infrared detectors (IR) and detectors with a combination of UV and IR receivers. The design philosophy of all these detectors is that the radiation receivers measure absolute radiation signals. For many combustion processes these detectors provide sufficient accuracy to distinguish if the flame is on or off , e.g. oil and gas firing furnace burners. However flames in acid gas burners are not easy to detect in a reliable way with these detectors since the combustion of acid gas does not provide enough UV radiation to detect the flame with a UV detector. Although acid gas flames can be perfectly detected with an IR detector, this does not result in a reliable safeguarding method as the hot refractory lining around the flame also emits sufficient IR radiation to keep the detector on!
Therefore the main question is, is there a detector available which can detect the acid gas flame properly without having problems discriminating between IR from the flame and the refractory? Luckily yes there is, the answer is the DFD flame detector! DFD is an abbreviation of Duiker Flame Detector and this detector has been specifically designed to deal with the above difficulties