AUTOMATED SENSOR IS A POTENTIAL BREAKTHROUGH IN PURITY CONTROL

AUTOMATED SENSOR IS

A POTENTIAL BREAKTHROUGH IN PURITY CONTROL

Controlling the purity of molasses streams is a critical factor that defines the efficiency of the raw sugar making process.

A new instrument was recently developed to analyse the purity of a molasses sample within the mill very quickly, using electrical conductivity.

The prototype is the work of Queensland University of Technology (QUT) Research Fellow at the Centre for Agriculture and Biocommodities, Neil McKenzie, and the technicians at the QUT Banyo Pilot Plant.

A small milling project funded by Sugar Research Australia and conducted by QUT and Rocky Point Mill sought to test the instrument within the mill. The Chief Investigator was Industrial Chemist, Rocky Point Mill, Bruce Tyson.

“The instrument is a breakthrough. Currently, analysis of pan stage liquid streams is time intensive. Typically, only three analyses can occur in every 24hour period,” Bruce Tyson said.

“Some mills make only one analysis in that time. That is not ideal. Changes in purity are being recorded from samples that were collected in the factory more than 30 hours previously. This makes fine- tuning difficult in the factory.”

With the new automated instrument operating within the mill, all pan stage liquid streams (Liquor A, B and C Molasses) could be sampled and analysed every five minutes to provide an estimate of the purity of these streams more than 290 times a day. Having this timely purity information enables the pan stage to make optimal changes to the purity balance of the factory every hour.

The instrument is based on a previously developed laboratory analysis method. It uses a basic computer acting as a programmable logic controller.

The computer program is available for use throughout the Australian sugar industry. All other equipment used in the project is non-vendor specific. “The instrument is not a replacement for laboratory analysis; it is complementary,” Bruce said.

“A standard laboratory analysis needs to be undertaken to calibrate the instrument regularly.”

Unfortunately, only limited testing was able to be undertaken in the 2021 crushing season with further delays preventing testing this year.

Nevertheless, site testing refined the instrument controlling program and determined that the analysis cycle for a single instrument is fewer than five minutes.

It is hoped that other factories will be interested in trialling the instrument in the current crushing season before deciding to install the technology within the mill on a permanent basis.

The installed cost of the instrument is expected to be less than $30,000 per site, with no additional costs to calibrate the instrument to the current methods of laboratory analysis.

Chief Investigator, Industrial Chemist, Bruce Tyson with the At-Line Purity Sensor installed at Rocky Point Mill.