What material is used for the lining of the coal mill feed short pipe?
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The feed short pipes of coal mills are generally very prone to wear and penetration; apart from using ceramic linings on the inside, are there any better solutions?
The coal drop pipe cannot be lined with ceramic, as the large particles of raw coal cause severe erosion; over time, the ceramic coating completely wears off and ends up inside the coal grinder
So how do you address the wear issue?
There are welding rods, and coal is used for grinding, but it’s not clear whether that will work well or not
There are now wear-resistant pipes available, including seamless pipes made of 65MnM, 45MnM, 50MnM materials, as well as NM600 seamless pipes. However, these are limited to small diameters; those with diameters below 180 mm are more common, and they are mainly available in regular stock.
A wear-resistant alloy layer is welded on, offering resistance to high temperatures, impacts, wear, and corrosion; the metallurgical bond ensures it does not come off easily.
Some baffles are welded to the side of the worn pipeline, allowing coal to fall on them and thus forming an anti-wear layer; when new coal falls on top of the old coal, this helps to provide wear resistance
It depends on the width of the welding baffle; it’s 20–40 mm. The spacing between multiple layers also needs to be carefully considered
In many cases, ceramic tiles are used, but using silicon carbide wear-resistant materials as an inner lining provides a longer-lasting solution; the critical areas can be made thicker to ensure long-term performance