ATMOS Technology: Sustainability from standard to structured premium tissue

Making tissue means enclosing as much air with as less fiber as possible. Bulk and caliper are fundamental quality features, as they result in absorbency for towel rolls or in structural and surface softness for toilet rolls, which are the main tissue products in terms of worldwide consumption.

Rogério Berardi, Manager - Tissue Technology Marketing/Voith Paper Thomas T. Scherb, General Manager R&D Tissue/Voith Paper

Bulk and caliper are important tissue quality features, divided into three categories according to the global requirements of different markets: standard, intermediate and premium, as shown on Graphs 1 and 2. These quality categories can be produced using different technologies, but the Voith Paper ATMOS technology is the only one available on the market that is flexible enough to swing between those three tissue quality categories, allowing tissue producers to adapt to the different regional market requirements.


ATMOS FOR STANDARD TISSUE QUALITY. The standard tissue quality is produced on dry crepe tissue machines. This technology has been available on the market for many decades, normally as Crescent Formers or Duoformer machines with 1 or 2 presses, as well as shoe presses against the Yankee cylinder and a standard reeling system. The main factors that influence quality generation in this concept are flat sheet formation and pressing 100% of the sheet during the transfer to the Yankee, followed by the dry creping. The result is pressed fiber and a compacted sheet, while, on the other hand, the high solids after the press allow less thermal energy requirements for drying. The ATMOS machine can easily swing to produce standard tissue quality by replacing the structured fabric with a conventional felt and by passing the ATMOS module within a few hours.


ATMOS FOR INTERMEDIATE TISSUE QUALITY. Historically, ‘intermediate’ tissue qualities have rarely been found, as only few technologies can narrow the quality gap between standard dry crepe and structured premium TAD or ATMOS. The technology known to produce the intermediate quality category is the single recrepe (SRC), basically a dry crepe standard technology using two Yankees in line. Few industries have resorted to SRC due to its high energy consumption because of the two Yankees and its operational complexity by creping the very sensitive tissue sheet twice. In recent years, technologies have been developed to produce intermediate tissue quality based on the principle of wet creping/negative draw. The tissue sheet is formed between flat fabrics and pressed 100% to achieve solids above 40% and, then wet creped into a structured fabric for quality generation by running different speeds before being transferred to the Yankee cylinder for thermal drying. The wet creping/negative draw effect on quality is limited since it is generated at relatively high solids and since fibers and base sheet have been highly compacted during pressing before. Other concerns regarding those new wet creping/negative draw technologies are the operational complexity, due to the necessity of transferring the sheet from a transfer element with a smooth surface onto a structured fabric and running speed differentials which effects runnability, fabric lifetime and overall process efficiency. The most feasible alternative to produce intermediate tissue quality is to operate an ATMOS machine with fine mesh structured fabrics to increase the intimacy between the fabrics in the ATMOS module, resulting in dewatering to dryness levels typical for standard dry crepe machines (above 40%). Another alternative is to install a calibration press after the ATMOS module to reduce caliper and further increase dryness contents. The result is structured tissue production with intermediate quality between standard dry crepe and premium and overall energy consumption near or even lower than the level achievable with standard dry crepe technology.


ATMOS FOR STRUCTURED PREMIUM TISSUE QUALITY. The premium quality is the best tissue quality available on the market and is produced on through-air-drying (TAD) and ATMOS machines (Graph 1). Since 2006, premium tissue has also been produced with ATMOS technology and since the end of 2007 it is freely available on the market. With this concept, quality is generated during tissue sheet formation using the crescent former configuration of a conventional outer forming wire and inner structured fabric. The tissue is mechanically dewatered to 36-38% solids by combined high vacuum and temperature as well as low pressure field application in the ATMOS module. The sheet is carried by the structured fabric from the headbox to the yankee, avoiding tensile losses of fabric-to-fabric transfer. As with TAD technology, only a minor part of the sheet surface area is pressed during the yankee transfer, so 75% of the sheet remains protected in the structure of the fabric. Commercially, the ATMOS technology proved to be operationally simple and robust, allowing a high level of flexibility for grade changes along the complete range from structured premium to standard tissue, operating efficiently on virgin fiber as well as on 100% recycled fiber. Besides, the high solids allow up to 50% lower energy consumption values than TAD machines when producing premium tissue.


CONCLUSION. THE BENEFITS OF THE ATMOS TECHNOLOGY’S ABILITY TO SWING BETWEEN THE DIFFERENT TISSUE QUALITY CATEGORIES ARE SUMMARIZED IN THE ABOVE TABLE. The combination of being able to save energy and fibers as well as to run with 100% recycled fiber, together with the ability to easily swing between the three different tissue quality categories, make ATMOS an environmentally friendly technology and hence the most feasible and sustainable alternative for tissue producers to work out an optimum quality/cost ratio in their market region, respecting any regional market requirements.




 ATMOS for Standard tissue

• Easy swing from ATMOS to standard tissue: replacement of the structured fabric by a felt in less than 4 hours


ATMOS for Intermediate tissue

• Easy swing from premium to intermediate

• Suitable for toilet and towel paper production

• Up to 50% higher quality than Dry Crepe

• Up to 15% lower energy consumption per case than Dry Crepe


ATMOS for Structured Premium tissue

• Same premium or even better quality than TAD with 100% virgin or recycled fibers

• Up to 50% energy savings versus TAD • Up to 30% fiber savings versus Dry Crepe

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