Thursday, 22 May 2014 07:07

Top quality from the very start

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Every paper manufacturer wishes that its new system will achieve good performance after a successful startup. This happened exactly when Bohui Paper’s BM 3 was commissioned. The board machine’s starting curve and efficiency were very good from the beginning. In addition, the product, a quadruple-coated ivory board, conquered the market within a short time.

bohui

Production on the BM 3 began last year and launched a new chapter in the history of paper and board manufacturer Bohui Paper. Although it is a long-established company from the Chinese province of Shandong, the BM 3 was the first machine going into operation at its Dafeng site in Jiangsu Province, where the company plans to install other board machines. One year after commissioning the paper manufacturer is very contented with the performance of the BM 3 as Huang Ju, Vice President at Bohui Paper, confirms: “After a very fast start-up, we have soon been producing paper of perfect quality. We are very happy to work with Voith, a partner with large technological experience and know-how.”

Proven components, modern technology. With a wire width of 8,750 mm and a total length of 400m, the BM 3 is one of the most efficient board machines ever. It is designed for an annual production of 750,000 metric tons of quadruple-coated ivory board in the basis weight range of 290–340 g/m2. The machine components for the complete production line were supplied by Voith, as were the entire automation technology and the first clothing.

The BM 3 features three Master Jet III-F headboxes and a three-layer wire section with a latest generation DuoFormer D. On the wire section’s intermediate ply a DuoShake ensures optimum fiber orientation and higher strength values. The press section consists of a double felted Tandem NipcoFlex press for a maximum line load of 800 kN/m. A steam blower box is installed upstream of the second nip for moisture cross profile control. An offset press ensures the high surface quality necessary, while surface smoothness is achieved by an EcoCal Hardnip calender with nozzle-type moisturizer and a heated roll with FlexiTherm coil. The coater consists of four DynaCoat AT coating units that use JetFlow free-jet applicators for non-contacting application of the two preliminary coats, the rear and top coats. At the end of the production line a Sirius roller with EcoChange reel changing system rolls up the ivory board for downstream processing by two VariFlex winders.//

Shandong Bohui Paper Group Ltd.

The Shandong Bohui Paper Group Co., Ltd. was established in 1994. The paper and board manufacturer headquartered in Shandong Province employs 5,000 people and produces ivory board, graphic papers, testliners, kraftliners and plasterboard.

Bohui BM 3: Information on the Voith scope of supply

Headbox and wire section. Three MasterJet III-F headboxes with lamella technology: the headbox with dilution water technology in the intermediate ply ensures optimum cross profiles. The wire section is a conventional three layer wire section with a DuoFormer D on the intermediate ply. The DuoFormer D is one of the latest generation formers from Voith designed for very high dewatering performance. In addition, a DuoShake is used on the intermediate ply for optimum fiber orientation and improved strength values.

Press section. The press section consists of a Tandem NipcoFlex press, followed by an offset press for optimum surface quality. Both NipcoFlex presses are double-felted and designed for a maximum line load of 800 kN/m. A steam blower box is installed upstream of the second nip for moisture cross profile control.

Sizing press and dryer section. The pre-dryer section is normally two-tier, with the first three dryer groups single-tier with DuoStabilizers. The SpeedSizer AT can run in SpeedSizer mode and as a conventional sizing press, in which case Voith SizeWings enable higher operating speeds for starch feeding. At the end of the after-dryer section there is an EcoCal Hardnip calender including upstream nozzle-type moisturizers to obtain optimum smoothness in the base paper. To also achieve optimum smoothness at high speeds, very high temperatures are necessary on the heated roll, so it is fitted with an external FlexiTherm coil.

Coating section and finishing. The coater comprises four DynaCoat AT coating units, each with a JetFlow free-jet applicator, which applies the coating color in a contactless fashion less likely to cause damage. The first two coating units apply the preliminary coat, the third applies the rear coat and the fourth the top coat. The coating is dried by means of InfraAir drying, InfraRed dryers, MCB high-performance dryer hoods and an HCB Turn air drying and contactless web turning system.

A curl correcting section with six drying cylinders corrects the paper curl. The final surface treatment is done by the EcoSoft calender. To reel up the high-quality board without damaging it a Sirius roller with EcoChange reel change system was installed (maximum winding diameter 4.4 m). Two VariFlex winders perform the next process stage.

The automation technology comprises

  •     the process control system for stock preparation, the wet end process and the steam, condensate, hood and air systems of the board machine.
  •     the machine-level control for the complete board machine
  •     the entire quality control system with six scanners and
  •     the complete machine monitoring system for monitoring the roll bearings.

Clothing. Complete first clothing for the board machine.

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