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Challenges of sizing using agri waste

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Challenges of sizing using agri waste

March 17, 2013 - 16:00

MUMBAI, INDIA, March 18, 2013 (RISI) -In July 2012, Bellmer started-up a new TURBOFilm SizerTMfor Kuantum Papers in India. After dismantling the existing coater and erecting the TURBOFilm Sizer, the startup was carried out smoothly and the original goals of the project were quickly reached.

Kuantum Papers, based in the district of Hoshiarpur in the state of Punjab, produces sized and pigmented paper from agro vegetation such as Sarkanda grass and Kahi grass and agro residues such as wheat straw and rice straw. The use of these raw materials by Kuantum Papers to produce paper also helps to reduce environmental degradation since otherwise this raw material is burned.

Kuantum Paper produces sized and pigmented paper in a 54 to 100 g/m2basis weight range and its machine runs at 900 m/min with a total sheet width of 3.82 m.

Kuantum Papers had an urgent need to improve its papermaking process and the Turbosizer fitted the bill. The paper machine was facing critical problems with the existing coater which was creating runnability and quality problems. The installation of the Turbosizer was possible thanks to the close collaboration between Kuantum Papers and Bellmer through its representative company in India, Brown Multitech.

The goal of the project was to improve the paper strength and also reduce paper breaks created by the existing coater. This machine modification had to be done in the most cost-effective manner for it to be a profitable project for Kuantum Papers. With this in mind, existing elements of the paper machine such as web run elements and coating kitchen were reused. Also the new TURBOFilm Sizer was optimized to fit into the available existing space.

The TURBOFilm Sizer is flexible, allowing operation with different media such as sizing, pigmenting and coating. It can also run at much higher consistencies than a conventional size press.

The application of the media is made through the applicator heads against the applicator rolls. The applicator heads can be equipped with either driven grooved rods (for volumetric application) or plain rods (for hydrodynamic application). Once the film is applied against the applicator rolls, it is transferred to sheet by the nip between the rolls. This ensures the film penetration into the sheet and enhances the sheet strength properties.

The new TURBOFilm Sizer provides a very accurate control on the film application thanks to its various features. The edge doctors allow the control of the total width of the media to be transferred to the sheet by placing the doctors in the desired position. This will avoid applying the media to the surface of the applicator roll in the nip and only will be transferred to sheet. The edge doctors are equipped with showers and collecting trays to collect the media in this area that will not be applied to the sheet.

The interchangeable application rod is another tool used to control the amount of media transferred to the sheet. Depending on the type of rod (plain or volumetric) and also the diameter of the rod, Kuantum will be able to control the quantity of media applied against the applicator rolls.

The applicator heads are equipped with a thermal stability system that avoids temperature difference between the media and equipment.

To control the volume and pressure of the media being applied, the applicator heads are equipped with a sealing blade against the applicator rolls. This sealing blade has two objectives. From one side it ensures the correct transfer of the media between the thermal stability chamber and the applicator rod. This helps to avoid any leakage of the media out of the circuit. Secondly, on the other side the sealing blade, there is constant pressure and excess media is recirculated because of the incorporated slots in the sealing blade of the recirculation system.

One of the main benefits of the new equipment is that it allows operation with a higher solids content of the media (sizing, pigmenting). This means that less water is being transferred to sheet, thus reducing paper breaks. As a consequence, the quantity of steam required to dry the sheet in the post-dryer section is reduced. This can be easily verified by viewing the accompanying charts with the data obtained after the installation.

Kuantum Papers has been able to realize not only all the initial targets of the project, but has also achieved further benefits. The wet web tensile of the paper sheet was increased, paper breaks were substantially reduced and, therefore, the machine runnability was improved thanks to a higher solid content operation. This has increased paper production and income. Additionally, the mill has been able to save money by the reduction in steam consumption.

Figure 1 - Comparision existing coater versus TURBOFilm Sizer - Water evaporation post dryer section
Figure 2 - Comparision existing coater versus TURBOFilm Sizer - Steam Consumption post dryer section
Figure 3 - Annual steam cost saving by using TURBOFilm Sizer