Case Study: Product transition

Milling Start-Up Using Off-Line Particle Size Analysis

Starting up a new process typically involves a series of iterative changes to process settings until the particle size (blue line) is within the required specification (dotted orange lines).

These iterations are necessary when using off-line particle size analysis techniques. Following any process changes there will be a delay as the process reaches steady state (green circles) before sampling can be undertaken (red circles). Further time is taken in waiting for the off-line measurement to be completed in the laboratory and results communicated to the plant operator.

In the above example, which used off-line measurement techniques, it took 50 minutes to achieve the required particle size - defined as a series of two successive in-specification measurements.

Milling Startup Using On-Line Particle Size Analysis

Using in-line, real-time particle sizing there is no requirement to wait for steady state conditions or to rely on results arriving from elsewhere. Process changes can be implemented immediately and dynamically to ensure that the desired particle size is achieved as quickly as the processing equipment will allow.

In the following example the process was brought within specification in under 8 minutes.

The resulting 40+ minutes decrease in processing time reduces the need to store, reprocess, or downgrade the out-of-specification material, and reduces the amount of energy consumed in 'tuning' the process.

Milling Efficiency Increased by Detecting Product Changeover

Using Insitec systems it is possible to know exactly when the milling product changes from a transitionary state to the final specification. This minimizes the amount of 'in-spec' product sent to 'off-spec' collection bins.

The following example shows product changeover on a cement mill.