Breaking records from the start of the lifecycle

Reuniting with Valmet in Nanning  

In March 2022, after Sun Paper took over the Nanning project’s existing assets, it embarked on comprehensive upgrades and transformations. Valmet supplied the second-phase pulp line’s digesting, washing, screening, and bleaching sections, focusing on producing high-quality bleached hardwood kraft pulp. The renewed collaboration stems from a successful partnership in the Beihai project. Deputy General Manager Ying remarks that Valmet is the industry’s strongest company and a highly trustworthy supplier because of its comprehensive capabilities. “The successful experience of the Beihai project and Valmet’s process technology’s reliability were why we chose Valmet again,” says Ying Guangdong. 

The project took only 18 months, successfully starting up more than two months ahead of schedule.

More than two months ahead of schedule

The second-phase pulp line project at Sun Paper Nanning set new industry benchmarks for construction and start-up speed, marking another highlight in the collaboration between the two parties. The project took only 18 months from contract signing to a successful start-up more than two months ahead of schedule. To ensure smooth system operation, optimization was prioritized after the chemical pulp line started up. By the end of November 2025, within about six weeks, the line had achieved full production capacity. 

“We attribute the project’s success to our highly capable and experienced young team, who are particularly rich in frontline production expertise. Special mention should be made of the team led by General Manager Zhang Chao of Valmet’s Xi’an workshop, who facilitated the early delivery of Valmet’s domestically produced TwinRoll press,” enthuses Ying Guangdong. 

From preliminary technical discussions and equipment supply to onsite installation and post-start-up guidance, Valmet provided full lifecycle services, offering critical support for the Sun Paper Nanning project’s smooth progress and the training of pulp line personnel. 

High yield and stable product quality 

The second-phase pulp line in Nanning employs Valmet’s continuous low-temperature cooking technology, featuring a two-vessel configuration for impregnation and digesting. It includes complete units for chip handling, impregnation, digesting, blowing, liquor circulation, and intelligent control. The system relies on low-temperature uniform digesting technology to achieve precise control, from raw materials to finished products, delivering high yield and stable product quality.   

The TwinRoll presses at Sun Paper Nanning were produced at Valmet's Xi'an factory in China.

Reliable results with Valmet technology 

The chemical pulp line is equipped with 10 TwinRoll presses produced by Valmet’s Xi’an workshop, and the operating capacity has exceeded the design capacity, with washing efficiency consistently above 90 percent. The line uses Valmet’s Delta Screening Technology to seamlessly integrate both coarse and fine screening processes, and the bleaching section uses a three-stage Dht–EP–D1 bleaching process. 

The TwinRoll presses have exceeded the design capacity, with washing efficiency consistently above 90 percent.

Between 80 and 90 percent of the valves used in the plant are Valmet valves. Sun Paper chose them again for this new project, having already used them in different lines in Yanzhou, Beihai, Zoucheng, and Nanning. Valmet services have provided technical support since the selection phase and are available 24/7 to discuss any issues over the phone. It is this reliable collaboration throughout the lifecycle that has made Valmet valves the default choice for Sun Paper over the past 14 years. 

Neles™ valve products are used in key positions of the second-phase chemical pulp line at Sun Paper Nanning.

Reliable collaboration throughout the lifecycle has made Valmet valves the default choice for Sun Paper over the past 14 years.

Ready-to-use automation 

The intelligent control solution created by Valmet for Sun Paper Nanning enabled quick commissioning of the Valmet Digester Control System. Thanks to the excellent compatibility between the core instruments and automation systems, the system could be directly switched to closed-loop control without requiring a manual operation transition after onsite engineers completed instrument testing. The system precisely reduces chemical and steam consumption, stabilizes pulp quality, and increases production capacity through closed-loop data analysis.  

Group photo of the Sun Paper Nanning and Valmet teams. The cooperation between the two teams on site was very smooth.

Developing long-term success together 

Sun Paper has always adhered to a prudent and steady investment strategy. Ying Guangdong explains that enterprises adopt different investment strategies at different stages of development throughout the lifecycle. “We must always maintain rationality and common sense, guided by the principles of production based on efficiency, sales, and availability.”  

Valmet looks forward to continuing their close collaboration with Sun Paper, driving mutual progress through technological innovation. 

Text: Dana Zhu
Photos: Jun Lu