Dry Powder processing in Dairy Industry
Dry Powder processing in Dairy Industry
Schwarzwaldmilch’s milk processing plant produce a wide range of dry powders made of milk, yoghurt and curd cheese as well as various non dairy products. Situated directly inside the production process and integrated into the spray towers NIR-Online process analysers measure the required contents of water, fat and other ingredients in real time.
The company regularly gets top awards for its dried dairy products, and just recently the German Agricultural Association granted a Gold Award for various milk powders produced at their production plant in Offenburg, Southern Germany. Customers from the pastry and confectionary industry receive high quality powders from skim-milk, whole milk, cream, yoghurt and curd cheese. The company also delivers various other drt products as a subcontractor for pharmaceutical supplies and extract of yeast which is used as a flavour enhancer in liquid relish.
Precise Data
It is essential that the facility can accurately reach the required fat and moisture value during production of each whole milk or cream powder batch. The objective is economical production of the highest quality dried food products and the process is started by receiving milk delivered by farmers which is separated and pasteurised into skimmed milk and cream in order to reach the necessary fat content.
The drying process starts by thickening the milk in a vacuum vaporiser. The residue is a milk concentrate which is shot in via nozzles or rotating discs into one of the three 20-metre spray towers. Hot air is then blown into the spray tower and mixed with the highly dispersed product. Water is evaporating whilst droplet fog falls to the tower floor with heat emitting from the cooling air. In order to reduce the remaining moisture a fluidised bed dryer is installed on the bottom of the tower where air streams provide a further drying process. Afterwards the powder falls through a steadily moving sieve into silos or directly into sacks.
Challenge for process engineering
The company now has its processes under control, even though the many different dry powders produced have the need for a high level of process engineering.
“We use the industry leading spectrometer from NIR-Online” said Klaus Selck the Quality Control manager. It allows seamless real time process control. These are compact, easy to use devices which have a vision panel and are placed at the end of the drying process. When the powder granules fall through the sieve they are steadily irradiated with near-infrared light, the returned light provides a read out by a diode array spectrometer. Absorption of the reflected light differs according to contained moisture, fat and other substances in the powder granules.
The measured data is then valued by the process software ‘SX-Center’ and displayed as a chart on one of the control room monitors. If set points deviate they can promptly adjust production in order to correct any unacceptable levels. Water content of a powder can be corrected by the amount and temperature of dry air or by the amount of inserted concentrate.
The company has combined two NIR-Online devices in the spray towers with a further laboratory device for adjacent quality control. The system replaces the previous two-stage laboratory test in which the Tower Manager took samples every hour and tested on site and additionally samples of the ready dried product were tested in the laboratory. “These methods were very costly and only gave a time delayed insight into the values of the dried products” said Klaus Selk.
Adjustments without delay
Using the process analysers from NIR-Online gives the benefit of measured results every second in real time. The analysers now supervise the drying of dairy products and yeast extracts in the two larger spray towers monitoring a water evaporation of 3000 kilograms per hour and the production of up to 3 tons of dried powder per hour.
“We have achieved reliability and real-time control of our production and we can react quickly to make necessary adjustments during processing. Expensive delays caused by laboratory processes have been eliminated and the Tower Manager has made him self familiar with the user friendly systems” said Klaus Selk.
The technology puts Schwarzwaldmilch in the position to accurately reach the required fat value for their dried powders and reach the maximum production capacity of the spray towers. Klaus Selk comments “The closer we come to the maximum moisture content the more efficient our production becomes – the ideal synthesis of quality and economy.
Summary of NIR-Online
- NIR-Online process analysers are the world’s first pre-calibrated, optical system for online analysis and control of organic and non-organic substances in production and processing. Due to their special configuration, NIR-Online systems can be integrated within nearly every production environment. The costs of traditional laboratory analysis are no longer required and instead of this random examination a continuous real time insight into the process is provided. Quality variations in production can be adjusted in seconds making long delays for laboratory results a thing of the past.
For non-organic products like metals or minerals the NIR-online system with an additional high resolution camera is recommended. The camera is able to measure the external features of the product even minimal differences in colour, structure and size allowing analysis of the chemical ingredients with results shown graphically.
Suffolk Automation is the sole UK Distributor for NIR-Online
Telephone 01473 829188
www.suffolk-automation.co.uk
