Acoustic chemometrics - monitoring of chemical production processes

Acoustic chemometrics is a new Process Analytical Technology (PAT) approach for on-line monitoring of industrial processes. Acoustic chemometrics concerns capturing system vibration characteristics, e.g. generated by a manufacturing process or by transportation flow. The resulting vibrations can be measured by non-intrusive, clamp-on sensors. Acoustic signatures carry embedded information about physical and chemical parameters, such as composition (oil, fat, ammonia, buttermilk, glycol, ethanol), mixing progress, fiber length, flow, density, temperature as well as system state. For extraction and quantification of these types of specific analytes and parameters of interest, domain transforms (FFT, WT) and PLS-regression is essential for multivariate calibration (process chemometrics). Acoustic chemometrics is here applied for monitoring of industrial production processes, a feasibility study of fluidized bed granulation of a fertilizer product (urea) (Semi-Industrial Pilot Plant: SIPP), illustrating the main acoustic chemometrics features and benefits. We also present examples of monitoring of ammonia concentrations also caused by turbulent flow. We finally discuss monitoring for visualization of critical situations early operator warnings. With acoustic chemometrics it is possible to monitor both process state and product quality for industrial process control. Relevant early warnings trigger the process operator to change relevant process parameters to control product quality or to prevent critical shut-down situations. Successful validation of these types of PLS-prediction models signify that acoustic chemometrics has matured into a proven on-line technology in the Process Analytical Technologies (PAT) domain. M. Halstensen et al. 2