Optimizing the impact of developments in micro-instrumentation on process analytical technology: a consortium approach

Abstract

What is process analytical technology (PAT), why is it important, and where is it going? Basically, PAT originated by applying measurement technologies to industrial processes. Some of the first examples of using measurement to monitor a process were performed within the German chemical industry more than 60 years ago [personal discussion with Dr. Jochen Rudolph, Director of Process Control of BASF, in Ludwigshafen, Germany, 30 September 1999]. The ability to monitor processes with measurement technology is not new [1], but the recognition that it will enhance productivity, quality, and environmental impact has grown increasingly over the past 30 years. PAT is now a field of measurement science that involves a number of contributions from the disciplines of chemistry, engineering, biology, data handling, and control strategies, applied in order to gain knowledge about the process being performed. The traditional approach to implementing PAT was to transport laboratory analytical instrumentation to the production plant and modify the instrumentation to accept a process sample. This traditional approach was valuable to the chemical and petrochemical industries for a number of years, as it was able to provide a window into the process, giving information on real-time composition, reaction pathways and kinetics, as well as environmental and hazard evaluation issues. Having instrumentation that could provide a profile of the process under production conditions enables the capabilities of the process to be defined, and to gather data needed to locate critical process parameters. Once these critical process parameters are monitored, process models can be developed or improved, ultimately improving process control. PAT therefore becomes a combination of applying process analytical tools and developing feedback process control strategies based on information management tools or process optimization studies for the purpose of achieving process understanding. Developments in measurement science are influenced by advances in the fields of computation and communication, driven by the needs of the military and computer-related industries. This results in better miniaturization techniques, new materials for heat transfer, new electro-optical materials, and new advanced data handling tools. With the large amount of new technology being developed within analytical sciences, it is important to ask the question: what type of measurement is appropriate for PAT? The answer is probably ‘‘anything that gives more data than you are presently obtaining’’. The constraints of cost and the reliability of the data must be recognized, but more measurement points usually lead to better models, resulting in better control strategies. The fact that more measurement data leads to better models also creates an opportunity to depart from the tradition of basing PAT solely upon traditional laboratory analytical instrumentation.