Four disruptive trends in tissue manufacturing

The tissue manufacturing industry is poised to undergo significant changes in the next five years according to the latest market analysis from Smithers Pira.

Its latest report The Future of Tissue Manufacturing to 2021 examines the background to this change, key market drivers and the disruptive technology trend that will help transform the industry in the medium term.

The last two decades have already seen significant changes in tissue-making technology which have changed the market – principally by decreasing market concentration in North America. Simple, relatively low capital cost crescent former tissue machines have expanded and diluted ownership of tissue production across a wider geographical base. This in turn has led to the emergence of new tissue manufacturing companies and converting companies.

Smithers Pira’s analysis has highlighted four key disruptive trends that tissue manufacturers, new and old, will need to respond to across the next five years to stay competitive in this increasingly dynamic market.

Significant changes are expected in the global tissue manufacturing industry over the next five years. Source: Smithers Pira

Crescent former standardisation

The arrival of the crescent former – with a single combined forming wire and press felt – has been a truly disruptive step for the tissue manufacturing industry. This has seen the development of more compact, lower cost machines where the wet web transfer to the press felt bottleneck is eliminated.

It is also the fastest tissue forming configuration with run speeds of up to 2,150 metre per minute now reported.

As machine builders and operators have embraced the potential of crescent formers, there has been a drive for increased standardisation. This has – and will continue to – eliminate engineering costs, as a limited menu of options greatly simplifying the process of building and operating a tissue machine.

Standardisation keeps costs down and lowers the bar for new companies to enter into tissue manufacturing by minimising the number of engineering staff they require. Across the next five years, this means it will be much easier for new tissue production sites to be set up, wherever and whenever a market need is detected.

Equally standardisation makes it much easier for a machine buyer to compare costs between different models, making for a more competitive equipment supply market.

Refining reduction

Refining tissue fibre is an old process that is going through changes as tissue product designs and chemical technologies evolve. The objective of the refining process is to modify fibres in order to increase the strength of the tissue. This has the added benefit of removing clumps and tangles of fibre as they pass between the rotor and stator bars.

In a traditional refiner with rotating and stationary plates, fibres flowing between the bars in the refiner are worked mechanically through compression and shearing forces. This results in structural changes to the fibres, including:

  • Chopping long fibres into shorter pieces,
  • Fibrillating the fibre surface,
  • Simple bruising of the fibre, which improves hydration and swelling.

Some types of fibres respond poorly to refining, with eucalyptus fibres are particularly fragile in refining for tissue use. In response to demand for these, many tissue mills are setting up separate split stock systems with refining on only the softwood side. This avoids refining the eucalyptus fraction and creating fines, in order to produce premium quality.

The future trend for tissue manufacture is for less refining, with plates designed for internal fibre swelling with minimal debris generation. The disruptive effect of this reduced refining trend will be seen in the increased use of chemical additives for dry strength control in tissue. This approach holds the promise of improved softness at a given strength level.

Savings in energy consumption during the refining phase are not significant. The reduced refining levels do have potential to improve pressing solids however, which translates in to drying energy savings of around 5%.

Development trials refining reduction are proceeding with several suppliers, and implementing the outcome of these is forecast to be a key focus across the next five years.

Foam forming

One established tissue process – foam forming – may witness a renaissance across the next five years. This technique involves forming tissue from a fibre solution suspended in a foam dispersion of air and water. It delivers dramatic improvements in both fibre dispersion and web formation.

Foam forming machines – like SCA Tissue France’s installation at Gien – have demonstrated how this process could allow for the substitution of lower cost coarser hardwood fibres for eucalyptus, while making similar or higher performance products. The business case for foam forming has been seriously eroded however, as the price of eucalyptus fibres has dropped.

Forthcoming disruptions in tissue fibre supply may create opportunities for foam forming technology to make a return in the next five years. Research has shown it can make reasonable tissue sheets from mechanical fibres. Furthermore the open wet foam tissue gives up water more easily than a conventional water-formed system – which leads to much better mechanical pressing efficiencies. Foam forming also offers benefits for energy consumption as well.

Press felt design

Press felt development trends are having an even greater impact on tissue manufacturing. Unlike in heavy paper grade productions, for tissue manufacturing single suction nip machines are continuing to displace Yankee dryer configurations.

This is because a single nip press puts the focus on press fabric performance – minimising the amount of water sent to the dryer section for evaporation. Pressing theory suggests that lightweight sheets like tissue have low drainage resistance and form pressure controlled nips.

Press fabric design has already been identified as a key to crescent former productivity. Past designs for dewatering the tissue focused on the mass of batt fibre, calliper, and air permeability. For the next five years the trend for tissue press felt design is to focus on pressure uniformity, mean flow pore size, compressibility, resiliency, density, and void volume.

Pressure uniformity and mean pore size are the variables best correlated to increased dewatering efficiency. This will translate into a reduction in dryer energy required, or a potential speed increase of the same order of magnitude as seen with foam forming. Critically, press fabric performance improvements, and the resultant energy savings, will not necessarily require capital investment in machinery. This will potentially disrupt tissue production over the next five years with output on dryer limited machines increasing significantly.

These cutting-edge trends in manufacturing processes, machinery developments, fibre technologies, and tissue end-uses; and their transformative impact across the next five years are analysed and contextualised in depth in the Smithers Pira’s report The Future of Tissue Manufacturing to 2021.