The Potential Utilisation of Electrical Resistance Tomography (ERT) in Milk Powder Processing for Monitoring and Control

Mohadeseh Sharifi, Brent Young

Department of Chemical and Materials Engineering, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand

b.young@auckland.ac.nz

ABSTRACT

Electrical Resistance Tomography (ERT) is a novel, robust, high speed and low cost method of process imaging which provides the user with the ability to perform non­invasive, remote internal inspection through volume scanning. This study describes the use of ERT in the non­invasive visualization of various milk solutions for quantitative auditing and attaining informative data, such as total solids content in the processing of milk to produce milk powder. Although various methods of concentration measurement have been proposed, most have disadvantages including inaccuracy and sampling problems. No other existing methods have the possibility of providing a continuous spatially distributed image of the data variation. Such a multidimensional picture of the dynamic state of the process provides for fundamental process monitoring and control.

This method provides an average accuracy of over 97% in milk total solids content measurement, which is similar to the accuracy of current methods of off­line point measurements, with the valuable advantage of providing continuous multidimensional data output which is critical for process control applications.

Keywords Electrical Resistance Tomography (ERT), skim milk, whole milk, total solids content