Wear on an ATOX® coal mill reduced by half as a direct result of a process inspection.
As one of its comprehensive Plant Service Maintenance packages, FLSmidth offers extended process inspections for grinding stations, including raw, coal and cement mills.
Root causes of high wear
The number one reason for higher-than-expected wear in a vertical roller mill is raw material composition being different from the composition for which the mill was designed.
A close second is the operation of the mill. This has a direct influence on the condition and performance of the mill and longevity of wear parts.
Optimised mill configuration, together with a thorough understanding of important parameters for mill operation, will not only improve production, but can also significantly reduce costs of wear and power consumption.
This was called for at a recent inspection of an ATOX® 25 coal mill that appeared to be suffering from abnormal high wear. FLSmidth was asked to evaluate the mill’s remaining lifetime.
It turned out that the segments on the mill’s rollers and table had become worn. The recommendation by FLSmidth’s service engineer was therefore to hard-face or replace the segments.
While on site, FLSmidth also investigated process parameters and operational procedures to find what was behind the high wear. It quickly became clear that the site’s operating procedures were causing adverse effects.
To counter these effects, the mill’s set-up and operational procedures were adjusted in accordance with FLSmidth specifications. The adjustments resulted in a significant drop in the total wear rate from 23.5 g/t to 11.8 g/t., in other words, wear reduction of 50 percent - equivalent to doubling the segment’s lifetime.
FLSmidth’s Plant Service Maintenance, which includes mechanical inspections and services, has been expanded to include process inspections. Mechanical inspections and services help maintain plant equipment in good working condition and ensure a long-term payback in terms of reliable equipment and stable production.
A process inspection is likely to lead to instant savings in fuel and power and increased production capacity. In addition, lower wear rates will reduce maintenance and the need for new parts.