Jiaxing is a city in the eastern province of Zhejiang which is situated along the yangstze River Delta - a burgeoning region of the aspiring Chinese nation. The city itself is actually known as “the home of silk” but it also has other vast textile, printing, leather and chemical industries operating in the area. Now the city and region can add paper and packaging to those products and skills. The emerging Ji’an Group makes the most of this local, thriving manufacturing hub. As a result the company is fast developing into one of the largest paper and cartonboard manufacturers in China.
Zhejiang Ji’an has a total of four paper machines, the first of which, PM 2, started up in 2005. The latest machines to be delivered, PMs 3 and 5 started up in 2011. The combined capacity of all four machines is 1.65 million tonnes/yr. Metso supplied PMs 1, 2 and 3, and Jiangsu Huadong Paper Making Machinery supplied PM 5.
Output from the mill is mostly sold domestically with the eastern area of China being the most important market. One of the key end uses for its white top liner board is for the growing beverage market and PM 3 is running at full capacity keeping up with demand. The company has plans to export white top liner board in the future.
Only the Best Technology
But operating in a fast development zone such as Zhejiang is not all a one-way street. Competition is fierce, and maximizing efficiencies from raw materials, particularly from recovered paper, is essential to maintaining growth prospects. Around 90% of the raw material at the Ji’an group mill is overseas waste paper from the US, Europe and Japan.
All these challenges have resulted in a farsighted policy at Zhejiang Ji’an in making sure that automation is at the forefront and maintenance costs are kept to a minimum, which is why investments in the most up to date technology take precedent.
In one of the latest developments at the mill, two new recycled fiber processing lines have been installed to feed high-quality furnish to the two newer machines producing white top linerboard.
In 2007, Andritz delivered a 1,300-ad tonne/day three-ply machine approach system to Ji’ an group for kraftliner production. Based on the success of this installation, three years later Andritz again received the order to supply two deinked pulp (DIP) lines:
One 350-bd tonne/day line to process old newspaper (ONP) and old magazines (OMG); and one 230-bd tonne/day line to process mixed office waste (MOW). Both lines include state-of-the-art continuous drum pulpers and flotation systems. The equipment delivery began in 2011 and start-up occurred in February 2012.
Andritz delivered all the process equipment for the DIP lines, including the sludge dewatering equipment. Auxiliary services included basic engineering, erection supervision, commissioning, training, and start-up.
Raw material for the first line is about 20% OMG and 80% ONP with an initial ash content of about 24%. Initial brightness is in the range of 50% ISO. Final brightness after the DIP plant is about 75% ISO with an ash content of about 15%. Yield is in the 73-75% range.
The importance of flexibility in operating a recovered fiber stock preparation line cannot be overstated, according to Michael Rosker, Andritz’s vice president for deinking systems. “The process must make full allowances for wide variations in furnish quality,” he says. “The fibers, fillers, and additives must be balanced to suit the machine’s characteristics and end user requirements. A tailored approachto DIP production is the answer.”
Central to each DIP line are two key technologies from Andritz: the FibreFlow drum pulper and the selectaFlot preand post-flotation systems.
The FibreFlow drum processes the incoming waste paper as gently and smoothly as possible to avoid cutting, so that contaminants such as plastics and stickies can be removed intact in the screening zone of the pulper and in subsequent screens and cleaners. To achieve this, high mechanical shear forces that might act negatively on the fibers and contaminants are eliminated. The separation, defiberizing, and coarse contaminant removal is achieved by rolling and gravity forces only. Together with the high consistency (approx. 25%), this accounts for the most gentle processing of wastepaper.
The ONP/OMG line is a two-loop system. After the pulper, there are process stages for high-density cleaning, coarse screening, medium-consistency screening, pre-flotation, low-consistency cleaning and cleaning, thickening, dewatering, dispersing, high-consistency bleaching, post-flotation, and thickening. Andritz also provided the FoamEx system and gravity table for sludge treatment as well as DaF for water treatment.
The 230-tonne/day MOW line is a three-loop system. The raw material is 100% sorted office papers or white trims from printing operations. Initial ash content is about 18% and initial brightness is about 65%ISO. Final brightness at the storage tower is about 85%ISO, and final ash content is about 8%.
Andritz was chosen as the supplier of the two DIP lines as there has been a history of successful collaboration with the Ji’an group in the recent past. As mentioned earlier, Andritz supplied a three-ply approach system for krafttop liner in 2007 and also a DIP line for MOW in 2010. Contracts for the latest twolines were signed in May of 2010 and both of them started up at the beginning of 2012.
According to chu Deming, manager of the pulp plant, the two Andritz DIP lines have been running very stably since their start up. “We have an established long-term partnership with Andritz,” says Chu. “And we are very familiar with the equipment the company supplies. They really have technical strength in their DIP lines.”
It also looks like the Ji’an group is going ahead with more expansion on the paper machine front as another 1.2 million tonnes/yr of board capacity are planned on three new machines. The Jiaxing authorities gave the green light to the project earlier in the year. The company has also announced a proposed forest-pulp-paper project foray into Fujian province, which is still at the preliminary stage.
Ji’an group is currently in the process of merging with anhui shanying Paper.