Industrial Process Monitoring of Polymerization and Spray Drying Processes

Abstract

Radical polymerizations in emulsion, suspension and solution are very important industrial production processes. To be able to control these processes to achieve good product quality makes the development of methods to observe these reactions in situ a very important topic not just in academia, but also in industry. In this paper, the advantages and disadvantages of different methods to follow emulsion and suspension polymerization reactions as well as spray drying processes are discussed from an industrial point of view. Calorimetry, near infrared spectroscopy and Raman spectroscopy are the methods with the highest potential for on-line applications. Droplet formation in spray drying can be observed by laser light scattering methods. Spectroscopic methods have used data analysis methods (principal component analysis, partial least squares) for a number of years. These methods can also be used as ''soft sensors'' Downloaded by [McGill University Library] at 07:24 07 February 2015 with standard process data. Examples how these soft sensors can be applied to emulsion polymerization processes are shown.

Polymerization Online Monitoring

“…Application examples can be found in the area of process monitoring and product quality prediction in batch polymerizations [30][31][32].…”

“…Multivariate methods, on the other hand, can also provide information to increase understanding of the process [30].…”

A Critical Overview of Sensors for Monitoring Polymerizations

“…A few additional studies using reaction calorimetry are also worthy of note. Hergeth et al123 combined reaction calorimetry and other spectroscopic techniques (near IR and Raman) to monitor monomer conversion in emulsion and suspension polymerizations. They mentioned that the main application of reaction calorimetry in a production setup is in the observation of the reaction itself.…”

“…Raman spectroscopy is a very promising on‐line monitoring tool for industrial purposes but one should be aware of potential signal interference from materials such as monomers, stabilizers and other materials commonly used at the industrial scale that may contain impurities which could fluoresce and affect the Raman spectra. Hergeth et al123 pointed out that by working at 1 064 nm to avoid fluorescence, other problems appear. They noted that the Raman intensity of a spectrum of a water‐based polymerization taken with a 1 064 nm laser will vary over the whole spectrum depending on how much laser intensity becomes absorbed by the water.…”

Modern process control techniques in the production of dried milk products – a review

“…The heat and mass transfer characteristics of droplets in a spray, in turn, depend on the droplet size distribution and change with temperature, solids content and time during drying of the droplets. Some of these product characteristics have been measured under limited ranges of conditions for some products [12]. Perhaps, in the future, it will become feasible to monitor droplet size distribution at the point of atomisation, or to predict the distribution using an inferential approach.…”