No breakdowns

At its cement plant in Aalborg in Denmark, Aalborg Portland has successfully run with the TRIBOMAX surface solution on a hydraulic roller press. After almost two years of operation on one of the plant’s grey clinker cement lines, the TRIBOMAX surface has brought about noticeable improvements in the roller press’ availability and performance.

Søren Ullits Sørensen, Process Engineer at Aalborg Portland, says that the aim of implementing the TRIBOMAX surface was to increase the roller’s lifetime.“We were looking for ways to improve the performance of our roller press and by October 2015, we expect to have seen 10,140 hours of operation,” says Søren Sørensen, adding that he and his colleagues are not only pleased with what they have seen, but they are also optimistic about the increased durability.

This is a significant improvement over the standard hardfaced surface. The average lifetime of a single roller with a standard hardfaced surface has been approximately 6,000 hours since the roller press’ commissioning at Aalborg Portland in 1987. According to Søren Sørensen, the roller press also suffered other unexpected breakdowns before the TRIBOMAX surface was applied. Eliminating breakdowns reduces the potential impact on operations considerably, largely because it can take four to five days to change the rollers, which is a significant amount of unexpected lost time.  

"We had too many breakdowns with the roller press before the TRIBOMAX surface was installed. We have certainly noted that we have fewer breakdowns as a result."

Direct comparison

The TRIBOMAX wear surface was fitted onto just one of the roller press’ two rollers so that direct comparisons could be made between the two. The TRIBOMAX surface sleeve was fitted during the course of one week in February 2013 and the roller press was soon up and running again. Run-in time, or the time it took to wear down the first millimetre, was approximately 1500 hours. Thereafter, the wear rate has corresponded to approximately 1 mm per 12,500 operation hours

Morten Munch Toft, Mechanical Supervisor at Aalborg Portland, explains that measurable improvements have been achieved: “We have measured the bearing temperature in the roller press as well as the vibrations and we can see an improvement. And it can operate at 100 percent capacity, which means it can handle everything we need it to.”

 

Unique surface properties

Another common cause of unexpected stoppages with roller presses is ‘fall through’. This occurs when the roller press loses its grip on the material being put through the roller press, meaning the material cannot be compacted. Fall through often occurs with fine material, such as dust. According to Morten Toft, fall through has been more or less eliminated, suggesting that the unique surface properties of the TRIBOMAX solution provide better traction.

Morten Toft is in fact highly impressed with TRIBOMAX's surface geometry, which in addition to offering better adhesion, is less prone to wear. Well-used roller presses tend to exhibit a ‘bath tub’ effect in which wear in the middle of the roller, where the pressure is the highest, occurs fastest. The TRIBOMAX surface resists this tendency, maintaining an even surface that enables a more consistent grinding bed thickness.  

A solution to trust

Niels Ole Cedergaard, Development Engineer at FLSmidth is pleased that the performance so far at Aalborg Portland indicates the great potential in the TRIBOMAX wear surface. From FLSmidth’s R&D Centre, Dania, Niels Ole Cedergaard has been one of the leaders behind the development of the TRIBOMAX solution.

 

He says: “The reason we developed this surface in the first place was to improve the performance of the roller press. We don’t want the surface to be blamed for the production breakdown and the TRIBOMAX surface goes a long way to ensuring this will not happen.” He adds, "It’s paramount for us that our customers get a solution they can absolutely trust.”