Efficiency is Key for High Capacities

At the Bohui Papers facility in the city of Zibo in Shandong Province, China, Cellwood Machinery’s largest dispersing system is helping the mill claim an impressive achievement: one of its lines can produce 2,150 metric tons per day of white-top cardboard—currently the largest capacity in the world. The Krima Disperser KD-1150, now in operation at Bohui as well as other locations, ensures the dispersion of recycled paper to the line.

Bohui Papers has been manufacturing paper using established equipment and high technical expertise for many years. The company places great focus on scientific and technical research and development. Bohui’s own research and development center continuously works with new processes, which has led to increased production and greater market share.


Bohui’s most recent investment, started in 2019, involved two new production lines tasked with producing cardboard from recycled paper. One line can produce 2,150 metric tpd; the other has a capacity of 1,500 metric tpd. The large volumes, combined with the white surface coating applied to the cardboard, puts great demand on the equipment.

computational flow dynamics

Fig. 1: Computational flow dynamics imagery shows that Cellwood Machinery has further improved its Krima Disperser from the original design (Case 3) to the newer design (Case 5.)

The purpose of the investment was to minimize the number of dirty spots in the cardboard. The better the quality of the base paper, and the cleaner the bottom layer is, the less risk there is of contaminants bleeding through the white surface of the final product.

“We chose Cellwood Machinery because they have an excellent reputation within dispersing and because it meant that we had Kadant as the main supplier for the rest of the line,” says Zhou Tau, project manager.

Cellwood Machinery supplied six complete dispersing systems, three of which were the new Krima Disperser KD-1150. This machine has significantly greater capacity than any of the company’s previous models. Development of the machine included a large number of studies, simulations, and flow analyses. The machine has been optimized to get through large volumes of recycled pulp and can be used in both new lines and in upgraded older lines.

The lines at the Zibo paper mill came into operation during March and May of 2019. The employees at Bohui Paper are very pleased with both the collaboration and the equipment.

“After start-up we experienced huge benefits from the machines running smoothly,” says Bohui’s Chen Qing Liang. He adds that production is running so well that the company very rarely needs to conduct test measurements before and after dispersing.

Within the next couple of years, Bohui plans to start another major cardboard project: a line with the breathtaking capacity of 1 million metric tpy, which is equivalent to approximately 2,800 metric tpd. This time, however, it will not be using recycled paper, but virgin pulp—pure cellulose from the forest.


Cellwood Machinery has been in business in China since the 1980s. The Chinese market started its impressive growth 20 years ago, and in 2008 Cellwood opened an office in Shanghai. Today the company has five local employees and more than 200 installations sold to Chinese paper manufacturing companies. Bohui Paper is one of many new customers.

Cellwood developed its newest model, the Krima Disperser KD-1150, through extensive flow simulations and technical improvements (see Fig. 1). The new disperser design is based on Cellwood’s world-leading models KD-450, KD-710, and KD-1050.

Research work has shown that the KD-1150 can produce up to 1,100 metric tpd with better energy efficiency and these improvements have been patented. Furthermore, testing shows that the fiber properties are developed to an even higher degree with the new design. This contributes to an increased efficiency in the stock preparation. Using an available upgrade kit, mills can cost-effectively upgrade an existing KD-1050 to get the benefits of the KD-1150 machine.