Upgrade of a multi-channel active noise control system for an industrial stack

Abstract

Active noise control has been studied in the 1990s as an innovative way to reduce the noise in specific situations. Some applications are well known today and found commercial success like noise-canceling headphones. However, the use of active noise control in industrial applications is more complex, thus being an uncommon solution in this field. The use of active noise control for industrial stack noise is one of these applications. One of the first large-scale implementation has been set up at the end of the 1990s. This system was a 10-channel active noise control system installed on a 1.8 m wide chimney to attenuate a 320 Hz pure tone. At that time, an 8 dB noise reduction was achieved at error microphones. Fifteen years later, it has been decided to upgrade the system with the latest generation of digital signal processor (DSP) allowing a real-time optimization and better tracking speed. This paper describes the overall system and the updated multi-channel active noise controller developed for this application. It also presents the improvements, the achieved noise reduction, and the associated environmental benefits.