Metso Insights Case studies Mining and metals refining A 9250-meter-long FLEXOPIPE belt cuts costs for AES Maritza East 1
Metals refining Mining
Aug 30, 2021

A 9250-meter-long FLEXOPIPE belt cuts costs for AES Maritza East 1

The Metso Outotec solution of replacing an old pipe conveyor belt with a new FLEXOPIPE belt has enabled AES Maritza to minimize operational costs, increase safety at the site and ensure undisrupted waste disposal process.

AES Maritza East 1 EOOD, an operator of a lignite coal powerplant located near Galabovo, Southern Bulgaria, is a part of The AES Corporation, a USA-based global energy company. The $1.4B 670-MW facility represents one of the single largest turnkey projects and foreign investments in Bulgaria to date, as well as one of the largest greenfield investments in Southeast Europe. It is the cleanest fossil fuel powerplant in Bulgaria, meeting World Bank environmental standards.

For many years, the AES Maritza site has been using a pipe conveyor belt for the transportation of the waste. However, after long use, the pipe conveyor belt has worn out, started requiring increasing maintenance costs and needed a more efficient and robust technology-based replacement. As a huge amount of waste is being transported on a regular basis from the plant to the waste disposal facility, there was also a need for equipment that would guarantee an undisrupted waste disposal process in order to ensure human and environmental safety.

At the end of September 2020, Metso Outotec crew successfully completed a month-long installation of a 9250m Metso Outotec conveyor belt in the pipe conveyor of AES Maritza. The delivered FLEXOPIPE conveyor belt is a 1500 ST1500 XP. With a belt width of 1500mm, the closed pipe belt with overlapped edges creates a diameter of 400mm, runs at a speed of 4.8m/sec and has a capacity of 1.400 tons/hour.


  • Constantly increasing maintenance costs on the old belt
  • Smooth, environment-safe and undisrupted waste disposal process


  • Installation of a new 9250m FLEXOPIPE conveyor belt
  • Implementation of the whole project, including delivery of the conveyor belt and vulcanization works
500m long conveyor belt being pulled into the installation
500m long conveyor belt being pulled into the installation

A solution ensuring safety for all people

The FLEXOPIPE conveyor belt has replaced a pipe conveyor used at the site to transport the waste for many years. 

FLEXOPIPE, as its name reveals, is a conveyor belt closed over almost the whole length of the conveyor and, therefore, holding all dust inside the closed belt. Systems for dust suppression are installed at the transfer areas to fully remove the risk of dust emissions during the transport of the waste. For more convenience, special noiseless rollers and additional noise isolating covers have been installed too.


Check the video
Flexopipe conveyor belt to cut costs for AES Maritza powerplant in Bulgaria


  • Lower maintenance costs
  • Increased safety
  • Robust technology equipment
  • Undisrupted waste disposal process
  • Better environmental conditions on the site

Lower maintenance costs and undisrupted waste disposal process

Pipe conveyor belts, or tube conveyor belts, are used for enclosed material transport. Metso Outotec’s FLEXOPIPE conveyor belts are ideal for transporting materials such as municipal waste, ash, limestone, or shredded tires, which might otherwise present an environmental hazard. After loading in the conventionally troughed belt, the belt is formed into a pipe shape with overlapped belt edges. The material is then completely enclosed by the belt.

Compared to conventional troughed belt conveyors, enclosed material transport brings remarkable advantages:

  • Horizontal and vertical curves enable the routing over difficult terrain conditions.

  • Fewer transfer points lead to smooth treatment of the material to be conveyed and reduce installation as well as operating costs.

  • The narrow width of the installation requires less space on the conveying track.

  • A larger contact between material and belt allows increased angles of inclination (depending on the kind of material being conveyed).

  • The material is completely enclosed so that external environmental conditions such as rain, wind, temperature, and dust have no negative influences.

  • Clean and spillage free material transport protects the environment and keeps maintenance costs down.

  • Additionally, in case needed, material can optionally be transported two ways.



Pipe shaped conveyor belt clearly showing the overlap at the bottom and no spillage below
Pipe shaped conveyor belt clearly showing the overlap at the bottom and no spillage below

Metso Outotec – an obvious choice

According to Mr. Tenko Palazov, Team Leader of AES Maritza`s Waste Disposal Facility, Metso Outotec became an obvious choice after proposing a solution with a great benefit-cost ratio.

“Given the long-term experience and reference installation Metso Outotec could present, they were the obvious choice for our project. They proposed the implementation of the whole project, which, in addition to the delivery of the conveyor belt, also included all difficult vulcanization works. At the same time, the complete solution was offered at a great cost vs benefit ratio and contained products with better technical characteristics than what we had in the past. The decision has been the right one. The installation and splicing jobs were done with the highest professionalism by the Bulgarian team and since the belt was installed, it has consistently performed,” he explains.

“We truly recognize Metso Outotec as a trustworthy partner with an amazing experience in conveying solutions. We are extremely pleased with the timely work they have done. The provided solution has reduced our operating maintenance costs, increased the safety levels and delivered better environmental conditions on the site,” Palazov adds.

“We are very happy that AES Maritza decided to implement our solution. Together with the colleagues from Metso Outotec Bulgaria, we succeeded in showing the client our experience, quality of work and demonstrated the benefits our solution could bring to them and their site. We have shown them a similar project we implemented at Maritza East 2 Power Plant to prove them this was not something we could not handle. And even in difficult COVID-19 times, we had no problem in keeping a constant dialogue and having experts regularly visiting the site”, says Paskal Brankov, Metso Outotec Sales Professional, Bulgaria.

“The good relation and collaboration with our customer made this a complete success. Of course, this has been the result of a great team effort involving many other colleagues from Metso Outotec. We clearly knew that this was a project of a big size but were sure we could deliver and execute with excellent quality. Besides being a project of great importance to our customer, it was also a very important one for the Bulgarian economy”, he concludes.

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