The ceramic solution: Enhancing efficiency and sustainability for operations at Vattenfall

Nestled in the ancient city of Uppsala, Sweden, lies one of Vattenfall’s most crucial facilities. This plant produces district heating, cooling and steam. As one of Europe’s largest producers and retailers of electricity and heat, Vattenfall is focusing on reducing their carbon footprint and enhancing sustainability within their operations.

With a heat capacity achieving 825 MWth, this is enough to cover 95% of the city’s energy needs with their population of approximately 180,000. The mission for the Uppsala plant is to reduce carbon dioxide emissions by approximately 200,000 tonnes per year, compared to when peat and other fossil fuels were used. Essentially, this will halve the climate footprint for the residents connected to Vattenfall’s district heating grid in the city.

In an effort to optimize their operations, Vattenfall embarked on a mission to increase productivity and sustainability while meeting the energy demands of its community. However, their current rubber bends were not the proper solution, as this caused leakage on the lime line every two to three months. Thus, they began looking for a reliable and durable solution for their issue.

Addressing high wear and productivity problems at the plant

Despite Vattenfall's commitment to ensuring efficiency, the operational challenges remained. Initially, rubber bends were installed as part of the pneumatic transport system for quicklime to the flue gas treatment, intended to remove hydrochloric acid and sulphur. However, the structure of the quicklime along with the speed inside the pipes resulted in significant wear problems for the bends.

The rapid change in flow direction in the bending areas – combined with abrasive particles – led to frequent failures. As a result, this was costing the plant more time, money and maintenance. It was also exposing the staff to work environment risks when the aggressive quicklime spread inside the building.

“What causes the high wear impact is a combination of pipeline geometry, solids shape and velocity,” says Dmitry Maygatov, Support Engineer, Pump technologies at Metso. “The configuration of the bend is the reason the flow is suddenly changed. The solids coming along the pipeline hit the place where the bend is installed, and with this impact comes higher wear to the bend. This combination leads to erosion, which in this case, causes critical damage where the pipeline changes its configuration.”

Unfortunately, the wear resistant rubber bends were not lasting longer than a few weeks. This recurring need for replacement was regularly disrupting the production line. Not only does this lead to strained resources, but also an increase in maintenance work and costs. Understandably, process reliability decreases if only one line is in operation whilst the other is being repaired. It was clear they needed a sustainable, dependable and long-term solution.

Recognizing the need for expertise, Vattenfall turned to Metso, leveraging their previously successful working partnership. Vattenfall began with Metso slurry pumps several years ago, and as they are continuously working, they relied on Metso, confident in our ability to mitigate the challenges posed by their deteriorating bends.

Researching for resilient solutions

In their pursuit of a lasting solution, Vattenfall set their sights on significantly increasing the lifetime of their pipeline infrastructure. Metso experts began researching the issue, reviewing the previously installed bends. By analyzing the samples and studying the internal surface and condition, Metso identified a critical pattern: the most worn area was localized along the outer curve of the bend's wall.

It became evident that standard materials such as rubber were not a good fit for such demanding conditions. Thus began the exploration of an alternative solution, a material which has resilience to a sliding type of wear.

The brainstorming session led to an intriguing proposition: Ceramic lining.

“Ceramic is perfect against both wear and high temperature, and we have had success with ceramic in different mining applications before,” says Maygatov. “This particular bend causes a sharp and sudden change of the flow, so in this case, most of the particles are flowing and hitting the surface with a different angle. We have previously seen that when solids flow along the surface, it helps to increase the lifetime, so this solution seemed promising to us.”

Engineering durability with Metso’s ceramic bend

Drawing from expertise in challenging mining environments, Metso engineered a ceramic-lined bend tailored to Vattenfall's specific needs. This emerged as the most viable solution, since ceramic has proven effectiveness in the most demanding mining applications, such as feed chutes and coarse solids pumping.

The ceramic bend is based on the standard Trellex 3D bend, incorporating natural rubber as a wear-resistant layer to withstand the dynamic impact of flowing solids. The ceramic lining is integrated into the rubber layer, where it is necessary to protect the bend against the heaviest sliding wear impact of the solids. By strategically reinforcing the bend's interior with ceramic lining, the aim was for optimal protection against wear in areas prone to high impact.

The ceramic lining covered the inner bends’s diameter exactly where the highest wear impact was expected to happen. This innovative approach combined the durability of ceramic with the flexibility of rubber, mitigating wear while maintaining operational efficiency.

“Normally, we recommend ceramic linings where high sliding wear impact can be faced, such as SAG mill discharge or cycle underflow. It’s the nature of sliding wear – since everything is flowing along the bottom of the end, that’s where there will be concentrated wear impact,” says Maygatov. “But unlike slurries found in most concentrator plants, this was a unique challenge because here, we were dealing with pneumatic transport."

This combination offers a dual benefit: the ceramic provides unparalleled durability against wear, while the rubber underneath plays a vital role in compensating for the small impacts that solids can have on the bend surface.

Through meticulous engineering and innovative design, Metso's ceramic bend solution promised to deliver enhanced durability, reliability and sustainability, addressing the specific challenges posed by Vattenfall's pneumatic transport system.

After extensive research and cooperation between Vattenfall and Metso, the bend with the ceramic lining was installed and a trial began in December 2022.

Trial and triumph with new innovative solution

In December 2022, a trial period began to gauge its effectiveness. Over the next two months, the Vattenfall team, in collaboration with Metso engineers, closely monitored the bend to assess its wear impact. To their delight, upon review, no significant impacts were observed on the ceramic lining. It was then decided to continue the trial until the wear impacts began to show on the bend.

As previously mentioned, the plant was replacing the bends every few weeks. Now, after 16 months and counting, the bend has remained in consistent operation since the initial installation. Unlike previous wear resistant rubber bend alternatives which required more frequent replacements, the ceramic bend continues to showcase longevity. This has inevitably resulted in cost savings, safety, sustainability, profitability and more.

“Once the ceramic bend was installed and proved to be a reliable solution, The plant has got an opportunity to work without problem with the bends in the gas cleaning lines,” says Maygatov. “The cost of the maintenance became significantly lower. A solution’s reliability increased a safety level.”

Partnering for progress

As Vattenfall continues their journey towards sustainability and operational excellence, their continued working success with Metso stands as a testament to the power of collaboration and innovation within the sustainability space.

“Metso experts had a methodical approach towards process evaluation. Even 14 months later, we can still say the product remains in good condition. Since then, we have also replaced 13 pieces of the ordinary models (rubber bends without ceramic lining). For Vattenfall, it means that there is a reliable installation with a minimal level of risk for the aggressive emission of the calc. This means higher safety for personnel", says Mikael Wikner.

In fact, due to the significantly positive results achieved by the ceramic bend, Vattenfall has decided to look for other places where this solution could be used, and the plant has made an additional order to replace all similar areas with Metso ceramic lined bends. This ongoing partnership highlights both Metso and Vattenfall’s dedication to empowering its customers with reliable solutions, paving the way for more sustainable and efficient operations.

The installation of this solution has allowed the plant to optimize their performance, minimize downtime and reduce their carbon footprint – all at the same time. At Metso, our strong R&D enables us to continuously look for new ways to introduce innovations for our customers’ benefit and work together to achieve their operational goals. That’s why, together, we are the partner for positive change.