Automated, On-Line Loss-on-Ignition (LOI) Sensor

Draper Laboratory has developed a prototype, automated system that measures on-line loss-on-ignition (LOI) in coal power plants. The system automatically extracts fly ash samples via a sample probe inserted into the flue gas stream and delivers them to an integrated thermo-gravimetric-analyzer (TGA) that analyzes the sample’s LOI according to the ASTM C311 standard. The integrated TGA is custom designed and built to be rugged and low cost relative to a laboratory grade instrument and can analyze samples every fifteen minutes. This LOI sensor is a major improvement in time and spatial resolution over the commonplace method of sampling fly ash from the bag house and sending it offsite for analysis. During field tests at actual power plants, the prototype system acquired ash samples and analyzed them while unattended. A proposed redesign for commercialization is also described.