Wear Resistance by 92% Alumina Ceramic in
Coal Mill Pulverizer and Pipe Line

Alumina
Ceramic liners offered by us find extensive usage to strengthen resistance
of surfaces from wearing as well as are also used for carrying out repairs
of surfaces in coal mills. These Alumina Ceramic are designed to provide
best performance and help in decreasing erosion possibility that is caused
by pressurized air that carries entrained abrasive solid coal particles.
Here, when angle of impingement is less than 30 deg, wear produced is
closely analogous to abrasion and if the angle of impingement is greater
than 30 deg to surface, particles from mill internals are dislodged by
impact erosion.
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Why Alumina
Ceramic Liners:
* Accumulated coal particles have abrasive wear mechanism same as
machining, grinding, polishing or lapping processes that are used for
shaping materials
* Here, two body abrasive wear (coal dust & mill internals) occur when
one surface (coal- harder than metal mill internals) cuts material away from
mill body and internal
* This mechanism changes to three body abrasion as generated wear debris
also act as abrasive with coal dust on mill internal surfaces
* The abrasion can be greatly reduced by fixing Alumina Ceramic Liners
especially on high coal accumulation areas
Coal Flow Concentration Distribution Within The Model
Pulverizer
A understanding the issue a study was conducted for seeing erosion pattern
of coal mill internals that happened because of coal flow in vertical
spindle pulverizers in PC Boilers. As coal & air mixture makes number of
turns before reaching Multiple Port Outlets, here the changes in direction
of flow cause majority of coal particles to accumulate in "Red marked"
portion of the pulverizer as defined in the diagram.
Based on above study, we - BMW have developed the following:
* Alumina Ceramic Lined Mill internals
* Multiple Port Out Let
* Mill Discharge Valves
* Coal flow Orifices
* Coal Pipe and Bends
These are well elaborated under their specific sections.