A coal-fired power plant typically has silos, bunkers or stockpiles in which the fuel is placed for storage purposes. Real-time feedback sensors are utilized to sense the coal height so data can be sent to downstream systems for further processing. These systems are required to accurately sense the height of coal within the bunker or stockpile. The range information is then fed in a real-time fashion to a control system. Inaccurate measurements can result in severe environment and safety consequences. The coal-fired power plant application is especially daunting due to the particularly harsh operating conditions and reliability requirements. There are many types of ranging sensors available in the marketplace. The performance of ultrasonic, radar, and laser rangefinder sensors was investigated to determine the height of coal stockpiles in various sites in a coal-fired power plant. A system to control the spacing of a telescoping coal-delivery chute above its coal pile was designed (using laser rangefinder), implemented, and tested. A detailed analysis of each sensor modality is provided, along with some conclusions regarding their performance. These systems are currently operational at a plant located in northeast Texas. The ultrasonic and radar sensors were part of legacy systems and the new laser sensor was integrated as a part of this study. The feedback signals from each sensor were compared to measured data. The implementation of the laser rangefinders proved to be slightly more accurate than the other legacy systems. However, the laser rangefinder systems have some drawbacks that have been listed.

Date of publication

Spring 5-1-2010

Document Type




Persistent identifier