Valmet Transforms Sun Paper’s Chemical Recovery Operations with Real-Time Process Monitoring

Valmet has completed the deployment of its Valmet Recovery Liquor Analyzer (Valmet Alkali R) at Nanning Sun Paper’s chemical pulp production line, enabling real-time monitoring and control of key chemical recovery processes.

The companies signed a cooperation agreement in January 2025, with installation and commissioning completed in September 2025. The project marks the first adoption of Valmet’s online liquor analysis technology across Sun Paper Group’s production bases.

Prior to the installation, Nanning Sun Paper relied on periodic laboratory sampling in its recovery boiler and causticizing operations. According to the company, the approach involved lengthy testing cycles and potential manual errors, limiting the effectiveness of process regulation.

Following commissioning, the measurement frequency of reduction rate increased by 56 times, while testing frequency for total alkali, active alkali and causticizing efficiency doubled. Valmet said the analyzer uses the same measurement principle as laboratory testing and incorporates automatic titration technology to improve accuracy and repeatability.

Nanning Sun Paper stated that the system has enabled a shift from manual sampling to continuous online monitoring, with key process data updated automatically every 10 to 30 minutes and displayed in real time. The company said operators can now respond more quickly to fluctuations in white liquor causticizing efficiency and sulfidity, helping prevent quality deviations and optimize process conditions.

According to Sun Paper, recovery boiler reduction rates currently remain between 89% and 94%, while excess lime in the causticizing process is maintained at 0.61%, close to the theoretical optimum.

Valmet’s South Regional Sales Director for Automation, Pan Zhifeng, said the project demonstrates the application of laboratory-grade testing principles in industrial online process control and provides data support for production optimization.

The project has also led to further cooperation between the companies. In January 2026, Sun Paper Group ordered two additional Valmet Alkali R systems for its Beihai and Yandian production bases.