FBG-Based Sensor Applied to Flow Rate Measurements

A flare system in oil platform is a combustion stack used to burn off excess gases that cannot be processed and gases that have to be eliminated in emergency shutdown to avoid the risk of explosion. Gas flow measurement in flares is still considered challenging because the measurement has to attend many specific demands, quite different from any other flow measurement application. For these types of measurements, many sensor technologies are available; however, they are all very expensive, and only a few ones can attend all demands. The objective of this article is to present a flow rate sensor based on fiber Bragg grating (FBG), cross correlation, and heatwave travel time techniques. The system was developed with inexpensive components and is little intrusive, capable of attaining the rangeability of the flare demand and independent of gas composition, pressure, and temperature.