Bioproducts are the future

​Metsä Fibre has begun building the world’s first new generation bioproduct mill at its Äänekoski site in Finland. Scheduled for completion during the third quarter of 2017, this facility will respond to growing demand for softwood pulp and make far more effective use of by-products.

Metsä Fibre is preparing to lead the field in an emerging world where the bioeconomy looms large. Demand is growing for products and energy based on renewable raw materials, with resource efficiency standards requiring us to optimise our use of these materials.

“Growth of the bioeconomy and restructuring of our main market area are steering us away from a concept focused exclusively on a single product. The wood that we use is also our most costly production factor, so obviously we need to maximise the added value that we extract from it,” explains Metsä Fibre Research VP Niklas von Weymarn.

Annual pulp production: 1.3 million tonnes

It has long been common practice to make use of pulp manufacturing by-products. Sales of tall oil, turpentine and bioenergy already generate more than 100 million euros annually, accounting for about ten per cent of the turnover of Metsä Fibre. The proportion of revenues from such co-products could even be expected to double in coming years.

The new bioproduct mill will have an annual pulp manufacturing capacity of around 1.3 million tonnes, comprising some 800,000 tonnes of softwood pulp and 500,000 tonnes of hardwood pulp. At approximately 1.2 billion euros, the facility will be the largest single investment in the history of the pulp and paper industry in Finland, and the largest wood processing plant in the entire northern hemisphere.

Minimised environmental impacts

The environmental impact assessment for the bioproduct mill began in spring of 2014 and was completed at the end of October, with the Regional State Administrative Agency for Western and Central Finland finally issuing the requested environmental and water abstraction permit in January 2015. Permission was also secured to commence operations based on this permit notwithstanding any appeal. An environmental permit was also issued for a bark gasification facility, a waste-to-biogas facility, a co-treatment plant for urban wastewater from the town of Äänekoski, and the Metsä Board wastewater treatment plant.

Even though the bioproduct mill will be more than twice the size of the present Äänekoski pulp mill that it will replace, its wastewater effluent and other discharges will remain within the limits of permit conditions for the present mill. One reason for continuing to satisfy these strict discharge standards is that water recycling in the bioproduct mill will be more efficient than anywhere else in the world.

The Äänekoskibioproduct millwill increasethe share of renewableenergy in Finlandby more thantwo percentage points.

“Use of the very latest and most effective technology in every aspect of this project is crucial from an environmental perspective. This includes minimising water consumption and arranging comprehensive recovery of malodorous gases to minimise odour emissions as well,” explains Metsä Fibre Project Manager Johanna Harjula, who was responsible for environmental impact assessment and permit procedures at the preplanning stage for the new mill.

Though admitting that the growing need of the bioproduct mill for cooling water will increase the thermal load on local waterways, Harjula notes that preliminary studies indicate that this will have no significant impact on fish movements or on the overall state of the waters. Efforts will also be made to reduce the normal thermal load discharged to waterways by using this heat for manufacturing new bioproducts.

While the bioproduct mill will generate a great demand for wood, this will not overtax the forest resources of Finland. The mill will increase annual use of wood fibre by about four million cubic metres, i.e. by ten per cent. Calculations indicate that annual softwood fibre logging could be sustainably increased by seven million cubic metres and birchwood fibre logging by four million cubic metres in Finland.

Odourless and free of fossil fuels

Metsä Fibre is seeking to make all of its mills entirely free of fossil fuels. The company’s mill in Joutseno has already achieved this objective during normal operations, and the same gasification technology will be used at the bioproduct mill in Äänekoski.

“Gas generated by gasifying wood bark, in combination with tall oil pitch and bio-methanol, will then replace the heavy fuel oil currently used in the lime kiln. We are also considering the prospects for generating gas from sludge produced at the mill,” von Weymarn explains.

Another advanced concept that immediately distinguishes the bioproduct mill from a conventional pulp mill is the conversion of malodorous gases to sulfuric acid. This chemical is then used for making the chlorine dioxide that is a key component in pulp manufacturing, and also for tall oil production. On-site production of sulfuric acid in turn reduces the need to purchase this chemical from external suppliers and has a significant impact on the sodium/sulfur balance of the mill.

“A reduction in unpleasant odours will also be the most obvious environmental impact that local residents will notice in the vicinity of the new mill,” Harjula adds.

A pioneer of energy-efficiency

The completed bioproduct mill will also be a veritable energy generating giant. One planning stage objective was to make it the world’s most energy-efficient mill, achieving a degree of energy self-sufficiency in making pulp and other bioproducts that enables the sale of surplus energy as biopower, and in other forms.

“The huge volume of steam produced in the mill’s recovery boiler will enable us to generate as much as 1.8 terawatt hours of biopower annually, which is equal to one quarter of the output of the nuclear reactors at Loviisa. The energy efficiency requirement and substantial output of biopower are further justifications for preferring a bioproduct plant over a conventional pulp mill,” von Weymarn points out.

In addition to biopower generation, the company is investigating the feasibility of using sludge from the mill’s wastewater treatment plant to make biogas in an anaerobic digester. This biogas could then be used for powering the lime kiln, and also as biofuel for motor vehicles. Another development path involves using tree bark together with energy wood for manufacturing a liquid or gaseous biofuel.

When operational, the bioproduct mill will generate about 1,500 new direct jobs throughout the value chain in Finland. The most significant benefits are anticipated for the job market in forestry and transport. The mill will boost Finland’s national exports and earnings by about 500 million euros annually, and also continue to act as a hub for a much broader business ecosystem.

“We are hoping that this project will also encourage other stakeholders to invest in the bioeconomy. We see ourselves as pioneers in this work, providing a much-needed boost in an otherwise gloomy economic climate,” von Weymarn says.

Building a bioeconomy ecosystem

As part of its bioproduct mill project, Metsä Fibre is currently following a total of eight development paths aiming at new bioproducts. The most advanced of these paths are gasification of wood bark to provide biofuel for the new mill, and use of malodorous gases for manufacturing sulfuric acid.

Development of bioproduct concepts will continue throughout the lifespan of the new mill, with a view to introducing new products gradually. Ideally the bioproduct mill will give rise to an entire new associated bioeconomy ecosystem providing roles for several other enterprises. Three potential partners have already been named: FA Forest Oy, Elastopoli Ltd and Itochu Corporation, which is a part-owner of Metsä Fibre.

New materials and fertilisers

Together with the Itochu conglomerate, Metsä Fibre is continuing work launched back in 2009 to develop a new process for manufacturing textile fibres from wood pulp. Metsä Fibre has been involved with research institutes and other pulp and paper industry businesses in research programmes led by Finnish Bioeconomy Cluster FIBIC Ltd.

Metsä Fibre is working with FA Forest to study potential uses for ash created in pulp manufacturing as fertiliser and earth construction material.

Metsä Fibre Research VP Niklas von Weymarn praises this initiative in particular: “This is an excellent example of the circular economy in action: we take wood from the forest and refine it into products, returning the resulting ash by-product to the forest in the form of fertiliser for new trees.”

Pulp can also be used for making various composite materials. Metsä Fibre has explored this development path in partnership with Elastopoli, which has set up a pilot plant to produce innovative composites of cellulose fibre and plastic for use in automobile parts and other applications.

Other progressive plans include refining lignin into novel bioproducts. This natural wood fibre binding agent is currently recovered in pulp manufacturing for use as a fuel for generating bioenergy.

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