August 22, 2017

22/08/2017: Energy savings in the milling process

by Ottevanger Milling Engineers

The choice for a specific grinding technique is key to the quality of the end product and the output of the production process

The milling process requires a significant amount of energy, which makes it worthwhile to monitor. In general, the grinding of raw materials is accounted for 20 percent of the energy consumption in the feed industry. This means that there is often room for cost saving.
A GHM hammer mill with feed device and double, automatic screen exchanger.Image credit: Ottevanger

No concessions

Making concessions will jeopardise the quality of the end product, from both a technical and a nutritional point of view. A technical reason for having a sound milling process is to create a solid basis for downstream processes such as mixing, expanding, pelleting and extrusion. The essential parameters of a milling process are the obtained structure and the particle size. Also, the milling process should have a sufficient capacity (t/h) and a low energy consumption (kWh/t). In addition, there are many other important aspects, such as maintenance (wear), explosion protection, noise level, and dust emissions.

Quality screens
For a reliable, efficient milling process it is important to use quality screens and it’s recommended to take mill manufacturer specifications into account. This ensures that the screens meet the requirements as regards:
• open area
• material thickness
• type of material
• type of perforation (Conidur or standard).

Two variants

In the feed industry, hammer mills are commonplace. Ottevanger Milling Engineers supplies two variants: mills with small diameters for 3.000 rpm and mills with large diameters for 1.500 rpm. Both variants have the same degree of reduction and the same hammer tip speed. The first category of hammer mills are compact but have a lower capacity. The larger mills (for 1.500 rpm) not only have a higher capacity, but they also produce less noise and heat in the milling chamber.

Squash effect
Hammer mills with adjustable breaker plates allow you to achieve a ‘squash effect’ by making the milling chamber asymmetrical. The particles then ‘bounce’ between the hammers and the breaker plates, which means they undergo a double impact and the desired structure is achieved faster. This means that less power is required to achieve a certain capacity, which results in significant energy savings. Of course, it is also possible to use the squash effect to increase capacity using the same power. Moreover, energy consumption can also be reduced by using hammer mills that are fitted with high-efficiency motors (EF3).

Read the full article, HERE.

Visit the Ottevanger Milling Engineers website, HERE.

The Global Miller
This blog is maintained by The Global Miller staff and is supported by the magazine Milling and Grain
which is published by Perendale Publishers Limited.

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