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."
In fact, the roller press has been running with the TRIBOMAX surface since February 2013 without any breakdowns, which is extremely pleasing.
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.”
Uninterrupted operationSince the TRIBOMAX surface was applied to this hydraulic roller press at Aalborg Portland, it has run without interruption for a total of 10,140 hours (end of September 2015).
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.”
What is TRIBOMAX?
The FLSmidth TRIBOMAX wear solution is a unique roller press wear surface designed specifically to withstand the demanding conditions of grinding clinker, slag and raw mix. Its high resistance to wear and surface overloading prolongs roller lifetime significantly, making it a highly cost-effective solution for roller presses.
The TRIBOMAX solution is based on known welding technology, but its formulation and constituent components have been especially adapted by FLSmidth to yield outstanding performance. Compared with traditional hardfacing solutions, which require frequent repairs resulting in downtime, the TRIBOMAX solution requires limited or no repair. In the unlikely event that the TRIBOMAX surface does become damaged, it can be repaired in-situ and rollers and sleeves can be refurbished as necessary.
The TRIBOMAX surface gives FLSmidth’s roller press rollers a guaranteed wear life of 25,000 hours or 40,000 hours for clinker grinding, depending on the specific configuration. For specific requirements, it is possible to ‘tailor make’ the guaranteed lifetime of the TRIBOMAX surface to higher values as well.
The TRIBOMAX wear solution is based on unique plasma transfer arc welding deposit technology. This results in a pure metallurgical composition with fewer impurities, such as cracks and porosities, compared with conventional hardfacing.
The microstructure of the TRIBOMAX surface formulations give it a special ability to achieve a high surface friction and an autogenous wear layer.
About Aalborg Portland
Aalborg Portland is a leading global building materials supplier with production units and sales and distribution companies throughout the world. Aalborg Portland develops, produces and markets a wide range of cement, concrete, granite and gravel products. Aalborg Portland produces grey cement in Denmark and white cement in Denmark, USA, Egypt, Malaysia and China. Its white cement is sold in more than 70 markets worldwide.
Aalborg Portland is part of the Cementir Group, an international supplier of cement and concrete that has its head office in Rome and is listed on the Italian Stock Exchange in Milan.