Wepa Group is one of the largest tissue manufacturers in Europe, with 13 sites, 21 paper machines, a production of approx. 780,000 t/year, and a positive annual growth trend. Since 2002, Toscotec and Wepa’s cooperation has been particularly strong at Wepa Marsberg-Giershagen, where Toscotec supplied a new tissue line on a turnkey basis, completely rebuilt PM 5 in two different steps and installed new hoods on other two existing machines, with the result that all tissue machines at the mill are now equipped with TT Hoods.
PM 4 and PM 7 Hood rebuilds: Consumption reduction & Speed increase
In order to evaluate the return on the investment, it is always interesting to compare the efficiency of the equipment – consumption and performance - before and after the rebuild. This comparison is particularly clear if we look at PM 4 and PM 7, where the modification involved only the hoods and the air system. After the installation of TT Hood on PM 4, the mill achieved a 12.5% reduction in gas consumption and 50mpm increase in machine speed. The results on PM 7 were similar, with a 13.3% reduction in gas consumption and 50mpm increase in speed.
In general terms, for a tissue machine that produces 30,000 t/y with a thermal consumption of 1.3MWh/t, 10% of drying energy savings equals a cost reduction of approximately 4 €/t, i.e. 120,000 €/y. Additional savings coming from electrical load reduction and machine speed increase must also be considered.
The above figures offer a clear picture of the potential benefits coming from the use of fully updated equipment including state-of-the-art devices dedicated to:
- Energy saving: complete heat recovery chains for steam generation, air and water heating
- Hoods regulation: automatic balancing system
- Pollutants control: burner management system, burner control and fine-tuning
TT Hoods: customized technology for the highest reliability
TT Hoods are entirely custom-made, in order to meet the needs of the paper machine. At WEPA Giershagen, Toscotec calculated the best combination of the open area, hole diameter, and hole pattern to achieve top performance and efficiency.
TT Hoods are designed and manufactured at Toscotec’s headquarters in Lucca, where its engineers and workers have more than 20 years of experience in hoods and air systems. This expertise guarantees the reliability and the constant improvement of their design and performances.
The art of project management in rebuild projects
Finally, time schedule is always essential in rebuild activities. Wepa Giershagen required Toscotec to schedule every phase of the project, allocating the right resources and time, in order to guarantee an accurate paper-to-paper machine shutdown period. On Wepa Giershagen PM 7 for example, the scheduled paper-to-paper shutdown was of 360 hours. The entire work was completed and tested in only 332 hours, i.e. 28 hours ahead of schedule.