New total solids and protein control in dairies

New total solids and protein control in dairies gives cost savings for both UF and RO systems

A new system of total solids and protein control using in-line process refractometers for use in certain dairy applications has been shown to provide cost savings when compared with Near Infra-Red technology (NIR) and be suitable for use in both Ultrafiltration (UF) and Reverse Osmosis (RO) plants.

GEA Process Engineering Inc., that has pioneered the new system, says that even using conservative predictions, dairies should be able to save around $160,000 a year on reduced powder loss alone plus additional savings in capital expenditure and calibration costs.

Modern dairies use UF and RO to produce an ever increasing range of value-added products. However many of the feed materials, especially whey, vary greatly in composition. Controlling the amount of protein accurately can have a dramatic effect on the amount of powder produced. For example, a 0.01% protein variation in the feed can affect the amount of powder produced by 1.5% (150 times).

Control options

There are two accepted methods of controlling protein levels: Mass Meter/ Density: this is an indirect measurement of solids by density. It cannot be placed in the final stage piping without mechanical modifications, making it more expensive to use. Near Infrared: this measures the total solids and protein directly after adequate calibration. Near infrared radiation is emitted and the absorbance of the radiation is detected and converted into relative amounts of important components.

The new system, however, uses a refractometer to measure the refractive index of solution. Solids are directly indicated, protein is indirectly measured by difference using permeate solids as the indicator. Although the protein levels are measured indirectly tests have shown that refractometer control achieves consistent results for target protein on a dry basis (PDB) equal to NIR technology.

Comparison with NIR

Control using refractometers has a lower capital and calibration cost than NIR, uses proven technology and the system is easier to program. Refractometers do, however, require two sensors, protein measurement is indirect and the variation in the feed composition may affect accuracy.

By comparison, NIR systems need only one sensor, measure solids and protein content directly, and accuracy is not affected by feed variations. NIR is, however a more complex, more expensive technology with higher maintenance cost.

Reverse Osmosis

Reverse Osmosis is being used increasingly to reduce water content in whey as well as skim and whole milk. At over 30% solids these products can become viscous and adversely affect the RO system. A single refractometer installed in the final stage piping can be used both for control and to warn of high solids levels. NIR is not yet available to handle the pressures in a RO system.

Conclusion

Using a refractometer to control the level of protein in a whey powder product is less expensive and less complicated than using NIR systems. However the most appropriate equipment will depend largely on each application. GEA Process Engineering Inc. will assess each plant individually and make appropriate recommendations dependent upon the process parameters in each case.

For further information about the new total solids and protein process control system, please contact:

Bruce Blanchard, National Sales Manager
GEA Filtration
GEA Process Engineering Inc.
1600 O'Keefe Road, Hudson, Wisconsin, 54016, USA
Office: +1 715 377 0533, Mobile: +1 612-868-1224, Fax: +1 715 386 9376
E-mail: bruce.blanchard@geagroup.com
www.geafiltration.com / www.niroinc.com

GEA Process Engineering develops, designs and sells production plants for the dairy, brewery, food and chemical industries. With sales of more than EUR 1 billion and approx. 4,000 employees working in more than 40 countries, GEA Process Engineering is recognized as a world leader in industrial drying, evaporation, crystallization, membrane filtration, cleaning (CIP), liquid processing, powder transport and packaging, and aseptic packaging.

GEA Process Engineering is part of GEA Group, headquartered in Bochum, Germany, and listed on the MDAX stock index. It is a globally successful technology group with more than 250 companies in 50 countries. GEA Group employs more than 20,000 people generating sales of EUR 5 billion. The company focuses on specialty mechanical engineering - especially process engineering and equipment and is one of the world's market and technology leaders in 90 per cent of its businesses.