Process Analytical Technology
PAT is The Key to a Better Process
Two questions for PAT expert Christian Knopf
Mr. Knopf, how is the PAT instrumentation of a batch process different to that of a continuous process?
Christian Knopf: In both cases, PAT can be used for process control and monitoring purposes. In batch processes, PAT can be used to initiate certain process phases or determine their end points. If a defined level of residual moisture is reached during a drying process, for example, this information can be set as a shut-down criterion for the dryer.
So, in continuous processes, it’s more to do with product quality?
Knopf: In continuous processes, the operator wants to and has to be certain that the product quality remains consistent at all times. Ideally, in continuous processes, PAT is inline—i.e., used in the product flow—which is why probes sometimes need to operate for several weeks without being cleaned. This means that self-monitoring concepts are required. Product and process information can be determined at several checkpoints in continuous processes, meaning that the amount of information covered for the measured product is very high. PAT systems can be used for specific purposes regardless of what information is crucial for quality.