Focus on Coal
Xwin 1003 Rolls; running at 1,300 ktons coal processed; 29 months; expected Xwin Performance Superiority 4x.
1003 HiCr Welded Roll;14 Months; + / - 600,000 tons.
Several factors will influence the type and the severity of wear. Te largest influences will be the quality of the coal being processed, the required capacity factor on the pulveriser, the PA mass flow rate, distribution, and resulting velocity profile around the bowl and pulveriser body and the orientation of the grinding elements relative to the velocity vectors. Quartz (SiO2), found in ash, is the most abrasive component of coal and has a hardness of 1700-1800 Vickers. Quartz, being dense, will tend to concentrate itself on the table/bowl. Te build-up of quartz on the bowl will increase the wear due to compression and the quartz that becomes entrained in the air stream will aggressively attack by abrasion the exposed grinding elements as well as the other exposed mill internals. A small increase in PA velocity can yield a large increase in abrasive wear when significant amounts of quartz are present.
Pulveriser grinding elements Pulveriser grinding elements that are composed of materials that can withstand these mechanisms of wear will aid by minimising the wear velocity on the tyres and the table thus maintaining a more consistent grinding profile for a longer period thereby achieving optimised grinding efficiency for a much longer duration.
Xwin castings, a composite matrix of granularised ceramic and a high chrome alloy, is such a material. Xwin castings provide the ductility expected of high
chrome alloys combined with the hardness of ceramic. Xwin has a composite hardness of 2100 Vickers compared with 700-850 Vickers for high chrome alloys and high chrome hardfacing. Te Xwin matrix provides a composite material with
a hardness and a wear resistance that is considerably in excess of the physical limitations of mono metal high chrome alloys and high chrome hardfacing. Xwin minimises the effects of wear to which the grinding elements are subjected during the pulverisation and primary classification process. Xwin is 3x-4x times more resistant than mono metal high chrome alloys. Xwin provides a longer lasting, more consistent,
wear resistant grinding element that is crucial to pulverizer operation, yielding longer operating campaigns, reduced maintenance, improved or maintained grinding efficiency and a lower overall invested cost. Xwin is the next frontier in material advancement for severe duty applications such as coal pulverization. l
Xwin® is a registered trademark and patented technology of the Magotteaux Group, S.A.
Enter 46 or ✔ at
www.engineerlive.com/ipe
Ken Birchett, Product Development Manager, North America, is with Magotteaux Inc, Pulaski, Tenessee, USA.
www.magotteaux.com
HiCr MPS 2800 BK Tyre; 3,000 hours; End of life.
Xwin MPS 2800 BK Tyre; 6,000 hours.
www.engineerlive.com 65
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68