Electricity + Control May 2016

ANALYTICAL INSTRUMENTATION

CIP – Clean-In-Place COD – Chemical Oxygen Demand FDA

– Food and Drug Administration

FFA

– Free Fatty Acids

IR

– Infrared

PAT POV TPM

– Process Analysis Technology

– Peroxide Value

– Total Polar Material

UV

– UltraViolet

Abbreviations/Acronyms

Power of light in industrial process management: Spectroscopy

Günter Pinkowski, KROHNE Optosens

Process Analysis Technology (PAT) is an essential prerequisite for the management and control of processes which is optimal, both technically and economically.

O ptical spectroscopy is a well-established method for quanti- fying compositions. It allows to maximise the performance of a system, for example, the so-called ‘space-time yield’: In addition to the use of ‘classical’ process measuring technology (flow, level, temperature, etc.) PAT tools are increasingly being used to achieve this aim. The requirements for PAT are very differ- ent; batch processes require a temporal extension of the measurements across all concentration ranges. The composition of the substance on the probe changes constantly. In continuous processes, however, the same composition or the same concentration often appears in only one point in the production chain and the measurements take place accord- ing to the various process steps. The ideal state of always knowing all relevant information or data would mean a great expense even in a small plant. With well-placed PAT measuring points, on the other hand, a higher level of control technology can be achieved and previously unused potential realised. KROHNE has developed the OPTIQUAD optical spectros- copy systems for applications with milk, wastewater and edible oil and fat. Typical applications include the continuous measurement of protein, fat, lactose and total solids in milk products, chemical oxygen demand (COD) in the wastewater flow of dairies or cheese factories, as well as free fatty acids (FFA), total polar material (TPM), peroxide value (POV), moisture, dirt and other values in edible oil and fat processing. The OPTIQUAD uses optical spectroscopy tomeasure the contents of milk products continuously and without contact. In the process, light of varying wavelengths is coupled into the product through an optical window. The system simultaneously determines the values of up to four optical effects (transmission, scattering, fluorescence and refraction) which manifest in different ways depending on the substances in the product, and then uses them to calculate for ex- ample in dairy applications the amounts of protein, fat, lactose and total solids. The measurement is tailored to the application with up to 12 wavelengths from UV to IR. The measuring cycle lasts only a few

seconds. Typical applications for dairies include strategically increas- ing the protein content in cheese making milk/vat milk, standardising the fat content in drinking milk or setting a constant ratio of fat to protein in cheese production. Unlike bypass devices which are sometimes costly to clean, the OPTIQUAD M measures without contact directly in the pipeline: the system is connected to the process via a standard VARINLINE process connection (nominal sizes DN 40

to DN 150). 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 nomov- ing parts. In addition, operating andmaintenance costs are lowered as there is no need for chemi- cals, reagents or cleaning products. Operating the device requires no special knowledge.

• Optical spectroscopy is an established method for quantify- ing compositions. • Optical spectroscopy systems have been developed for applications with milk, wastewater, edible oil and fat. • The OPTIQUAD uses optical spectroscopy to measure the contents of milk products continuously and without contact.

take note

Günter Pinkowski is managing director of KROHNE Optos- ens, a KROHNE subsidiary dedicated to optical systems, and has been working in the field of optical spectroscopy for more than ten years. Enquiries: Email g.pinkowski@krohne.com or J.Alexander@KROHNE.com

Electricity+Control May ‘16

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