Monitoring and controlling Corn wet milling using In-line and At-line NIR instruments

IntroductionDA 7300

Meihua Biological technology group co., LTD with head office in Langfang city, Hebei province in China is a leading food and feed additive supplier. With a trend of increased production of value added corn based products, the demand and benefits of using extensive process monitoring and automation has become obvious to the company.

The corn wet milling involves the separation of corn into starch, fiber, germ DA 7250and gluten. Maintaining moisture and protein close to target in all process steps is essential to keep operational margins. Meihua group has installed four Perten DA 7300 In-line NIR instruments for use in two factories in China, one in Inner Mongolia and one in Xinjiang province. DA 7300 in-line measurements are used to control the refining of the Gluten slurry to Gluten meal.

In combination with the in-line NIR instruments the group have 7 Perten DA 7200 at-line NIR instrument used for measurements on all major intermediates, both wet and dry, and end products.

Rapid NIR monitoring of production allows tightening specifications, improving control and reducing waste. A more consistent product lead to more satisfied customers and fewer claims. Automated measurements also allows for savings to be made as a result of reducing the number of laboratory sample analysis.

The DA 7300 capabilities with a camera looking into the production stream gives the operators the possibility to see the product stream and ensure the process is running smoothly.

Live camera images from the process
Live camera images from the process

Installation points and measurement control

In-line measurement control

The company has installed DA 7300 in-line units in the corn wet milling plants to control important process steps. Installations are done measuring on liquid protein slurry and dried protein powder. The flexible instrument front with various accessories makes mounting and set-up of the instruments very convenient.

DA 7300 Wet Gluten Slurry
The unique optical configuration of the DA 7300 allows for reflectance mode measurements, not needing to manufacture bypasses or placing any instrument probe into the product stream. The instruments are sanitary design and IP65 classed and can be cleaned in place. 

Measurements are presented in dedicated Perten graphical interphase as well as integrated into the plant control system using the DA 7300 external communication capabilities.

User interface with graphs
User interface with graphs and camera images.

In-process used NIR Calibrations

The DA 7300 and DA 7200 instruments are based on the same spectrometers and similar optics and it is possible to use the same calibrations on both instrument types. This makes the development and maintenance comparably easy and fast and ensures stable and accurate measurements.

Effect on operational results

The in-line measurements from the DA 7300 provide substantial returns. Corn gluten meal is one of the most valuable products from the milling process. Its price is dependent on protein and moisture content.

The speed and efficiency of the centrifuges and dryers can be actively controlled. In addition, the addition of starch slurry to the gluten slurry can be controlled automatically.

Without rapid process control, it could take hours before possible issues in the starch separations gets noticed, leading to large volumes of gluten meal being out of protein specifications. Added automation has decreased the variability in the protein slurry and end product gluten powder and improved the production yield. In addition, complete quality records of the entire production are available for traceability.

The extra protein powder yield in combinations with reduced need for routine lab analysis allows the instruments to pay for themselves very quickly.

DA 7300 in a chute

DA 7300 on a pipe

DA 7300 instrument installed in a chute
measuring meal

DA 7300 instrument on a pipe, with a sample
opposite, measuring slurry

 Read more about the DA 7300 In-line NIR here.