Paul Watson, Director of Research & Innovation, Canfor Pulp Ltd., Canada
Co-author: Wladimir Janssen, Tissue Specialist, Canfor Pulp, Canada
High quality NBSK, the present and the future in premium tissue products
The largest cost element of a finished tissue product is still the cost of the fibre. High quality NBSK is used profitably as a furnish component to obtain a high finished tissue product quality, in terms of softness, bulk and strength, and can have a positive impact on energy use and production efficiencies. Overall cost includes the furnish composition, energy use, and production efficiencies while reliably maintaining a required tissue quality level. From a technical view, especially in recent technologies that involve wet-shaping and the production of a structured sheet, NBSK plays an important role. In cooperation with Voith, Canfor’s NSBK was evaluated in Voith’s Tissue and Pulp Innovation Center in many trials using conventional and recent technologies such as Atmos and Tissue-Lev, and Canfor’s pulp has become the preferred softwood pulp. We expand on the fibre properties, optimum pulp preparation and its effect on the finished tissue product quality, as it relates to recent tissue making technologies.
Judson Fidler, Technical Customer Service Manager, Suzano Pulp and Paper America, Inc, USA.
Co-author: Manoel Silvestre Faez, R1D Innovation Technical Consultant, Suzano Paper & Celulose SA, Brazil
Eucalyptus fibre for long fibre replacement and maximising quality in tissue
Eucalyptus fibre is utilised in the manufacturing of tissue to provide superior paper properties as required by the end use segment. The Eucalyptus fibre is generally not added in the tissue process for contributing strength due to its shorter fibre length. Long fibre (softwood) is known to deliver an element of strength to the tissue paper. From a technical perspective, elevating the furnish level of Eucalyptus to provide strength may seem counter-intuitive.
Suzano independent research on a tissue pilot plant presented in this paper show how Eucalyptus can be used as a strength element and replace long fibre in tissue while maximizing physical properties such as bulk, geometrical mean tensile (GMT) and handfeel softness while maintaining runnability. Bath tissue with 100% Eucalyptus was the objective, working with process variables like refining strategy and headbox layering.
Aside from refining and process changes, upstream development work ongoing to enhance the strength of Eucalyptus from a pulp product perspective are discussed. The inclusion of additives in the paper process can also be an alternative to develop strength and replace long fibre.
Frank Cunnane, Product Manager, Cristini North America, USA
Process control tools to improve tissue machine performance
Tissue Makers have long lacked the ability to control the ramp-up in speed and steam during felt start-ups based upon actual felt properties, as well as the capability to predict a), the timing of felt washes and b), end of clothing life, in real time. Historically, either “black book” records or infrequent measurements of clothing water content and and/or permeability have been used to assist in these activities, but both of those techniques are fraught with inaccuracy and waste.
Methodology is presented herein that utilizes new instrumentation from Cristini in a strategy that both monitors the condition of clothing in real time, and can be utilized in a control strategy tied in with machine drive components, Yankee steam pressure or hood temperatures, and/or chemical dosages, to add an element of control not possible in the past. Pick-up felt break in time can be significantly reduced, energy consumption optimised, and felt life simultaneously extended.
Monitoring machine clothing on tissue machines has also presented a new variety of safety and environmental concerns. New instrumentation technology from Cristini allows real time outputs for clothing moisture content and permeability without requiring operators and technicians to make separate on-machine measurements in dangerous locations. Such practices have been banned in many corporations or jurisdictions. Cristini has developed fixed point or traversing measurement heads that allow direct connections to the machine’s DCS/MCS systems for data analysis. Fast Fourier Transformation (FFT) capabilities are included with this line of instruments, providing near instantaneous read-out of pulsation or vibration issues. All water content measurements are conducted utilizing harmless microwave radiation, eliminating the need for costly and less accurate gamma gauge usage.
Neil Davis, Global Technology Manager, Sonoco Products Company, USA
The core impact of evolving tissue and towel trends
To produce premium products that are softer, bulkier and more absorbent, leading tissue and towel producers are replacing conventional machines with TAD or ATMOS technology. But all too often, in their zeal to adopt new machine technology, maximize runtime with bigger rolls, and embrace more efficient automation, they overlook part of their ongoing consumables costs: cores. For tissue and towel producers, crucial aspects of parent core design and use can impact implementation speed, containment of recurring costs, waste reduction and sustainability.
Successfully incorporating innovative technology and advances in converting depends on considering core design and performance from the early stages of process engineering. Core-related decisions should include how cores will be shipped and received, how chucks and inserts will be incorporated into the design of a converting unwind, how white waste is to be removed, and if used cores can be re-cut and re-graded.
This paper and its presentation will greatly increase the audience’s awareness of core issues that will help them avoid waste, save money and take the hiccups and headaches out of new equipment start-ups and rebuilds for years to come.
Brandon Mahler, Paper Chemicals Innovation and Development, DuBois Chemicals, USA
Understanding and controlling press fabric filling
Tissue press fabrics can be significantly impacted by filling from various contaminants. Common additives used in tissue manufacturing can contribute to a reduction in fabric performance. When recycled fibre is used, stickies and inorganic fillers increasingly become sources of contamination to the press fabrics. This can lead to reduced production efficiency and more frequent shutdowns for fabric changes. Fabric filling can also cause mills to excessively use mechanical cleaning methods like needle showers, which can result in premature wear.
Traditional methods of used press fabric analysis can be inadequate to identify the materials filling felts in the tissue industry. Strength aids, Yankee coatings, and other materials that form gel-like depositions are challenging to identify and can significantly impact void volume filling. While fabric filling problems can be caused by a single contamination source, it is more commonly a matrix of different soils in combination. This presentation will discuss techniques to better identify sources of tissue fabric filling and review the findings from used fabric collected at numerous mills. Suggestions for improving the effectiveness of prevention and cleaning on machines will also be discussed.
Alexander Grüner, Global Marketing and Business Development Manager, emtec Electronic GmbH, Germany
Possibilities for process optimisation in the wet- and dry end of the tissue production
One of the main targets in tissue production is to reach the best possible quality with the lowest possible cost. To fulfill this target, it is necessary to use objective and reliable measuring devices to keep or get the production process under control.
To reach an efficient process and the best possible quality, objective testing in the wet and dry end of the production process is necessary. In the wet end it is extremely important to have detailed information about the charges of particles in the pulp suspension as well as of the surface charge of the pulp fibres. Already at this step of the process, the final quality of the product is influenced. At the dry end, it is necessary to get an idea of the quality of the base tissue after the production or the finished product after converting. This can be realized by the Tissue Softness Analyser, which gives information about the three single parameters (real softness, smoothness/roughness and stiffness), that define the final hand feeling.
By the use of adequate testing equipment, the complete process of tissue production from the pulp to the finished product can be controlled and guided in the right direction. Emtec as a developer and producer of such objective testing devices would like to explain and illustrate how the production process can be attended by those Charge Measuring Devices as well as with the Tissue Softness Analyser and how issues, such as under- or overdosing of chemicals – and by this a waste of money and material as well as a bad quality – can be avoided.