The uses of passive measurement of acoustic emissions from chemical engineering processes

Acoustic measurement techniques are being developed to monitor the state of equipment and the physicochemical changes within chemical engineering proc esses. The advantage of acoustics is that unlike other techniques, direct c ontact with the process under investigation is not required so intrusion ca n be kept to a minimum. Most research concentrates on the active use of low -powered ultrasound, i.e, the generation of an acoustic wave and the measur ement of any changes in the wave, This review highlights the use of passive measurement of acoustic emissions created by a process as a potentially no n-invasive, real-time monitoring technique to be used in process control. R esearch into the acoustic emission sources found in several chemical engine ering processes such as gas-liquid mixing, solid systems and chemical react ions and the process information that can be obtained from them is discusse d. (C) 2001 Elsevier Science Ltd. All rights reserved.