APP Sets New Board Making Speed Benchmark

After bringing its BM 6 paperboard machine in Xiaogang, China, back online earlier this year following a major rebuild by Voith, Germany, Asia Pulp & Paper (APP) reports that it now has crossed the 4,000 metric tpd (24 hr) production mark, with an operating speed of 1,103 m/min. The goal of the rebuild was to attain the 1,100 m/min speed level, which is now a new benchmark for the board making industry. APP and Voith note that at this speed range, no other multiply board machine has ever produced top quality art board products, as BM 6 is now doing.

According to APP and Voith, the rebuild was a big challenge for their teams because of the limited shutdown time of eight days. During this short period, Voith modified the wire, press, and dryer sections to fulfill APP's requirements. In the wire section, the newly developed suction forming boards were installed to reduce stock jumping at such high speeds.

In the press section, a new water doctor and save-all pans were installed before and after the first shoe press nip. This modification is reducing rewetting of the board at high speeds.

The most complex rebuild activity was done in the dryer section. Voith changed the concept of the existing steam and condensate system of the pre-dryer section. In connection with this, the Turbo Dryer S air caps were placed in the first two dryer groups. The goal behind installing the four gas heated air dryers was to increase the drying capacity of the pre-dryer section. To ensure a stable web run at 1,100 m/min, the open draw was rebuilt to become a closed web run system at the beginning of the second dryer group.

TAPPI
http://www.tappi.org/