Process analysis technology (PAT) is an essential prerequisite for the management and control of processes in the food and beverage industry. Optical spectroscopy is a well-established method for quantifying compositions, allowing for the highest performance of a system.
In addition to the use of classical process measuring technology such as flow, level and temperature, the requirements for PAT are very different. Batch processes require a temporal extension of the measurements across all concentration ranges as the composition of the substance on the probe changes constantly. In continuous processes however, the same composition often appears in only one point in the production chain. Measurement takes place according to various process steps. With well-placed PAT measuring points, a higher level of control technology can be achieved and previously unused potential realised.
Krohne has developed the Optiquad optical spectroscopy system for use in the milk, wastewater and edible oil and fats industries. Typical applications include the continuous measurement of protein, fat, lactose and total solids in milk products; chemical oxygen demand (COD) in waste water flow of dairies or cheese factories; and measuring free fatty acids, total polar material, peroxide value, moisture, dirt and other values during edible oil and fat processing.
The Optiquad uses optical spectroscopy to measure the contents of milk products continuously and without contact. During the process, light of varying wavelengths is coupled into products through an optical window. The system simultaneously determines the values of up to four optical effects, namely transmission, scattering, fluorescence and refraction. This then manifests in different ways -depending on the substance in the product.
The measurement is tailored to the application with up to 12 wavelengths. The measuring cycle lasts only a few seconds. Typical applications for dairies include strategically increasing the protein content in cheese making or standardising the fat content in drinking milk. It can also set a constant ratio of fat to protein in cheese production.
Unlike bypass devices, which are sometimes costly to clean, the Optoquad M measures without contact directly in the pipeline. The system is connected to the process via a standard VarinLine process connection. The measuring section is FDA-compliant and is cleaned using CIP. There is no need for daily recalibration thanks to the long-term stability of the optical measurement, which requires no moving parts. Operating and maintenance costs are lowered as there is no need for chemicals, reagents or cleaning products.