Stora Enso aims high with Imatra Pulp 2001 plan

Stora Enso's Imatra Mills in Finland are the subject of an extensive expansion project aimed at raising pulp, paper and board output by the end of next year. The group has implemented a five-point plan to help it reach this goal, but few people may realize how many sub-plots there are under the main scheme

by Caroline Jewitt

Stora Enso's Imatra Mills are situated some 250 km east of Helsinki on the southern shore of Lake Saimaa. The picturesque setting is home to the two production units that make up the Imatra complex - Kaukopää and Tainionkoski. The mills have a rich history that reaches back as far as 1897, when a groundwood plant and paper mill were built on the banks of the river Vuoksi in eastern Finland by a company called Aktiebolaget Tornator. This heralded the start of the wood processing industry in the Imatra area.

In the early 1930s, the company was acquired by Enso-Gutzeit Osakeyhtiö, which already had a pulp and paper mill down the river at Enso. The first pulp mill went into production in 1935 at Kaukopää and had a capacity of 80,000 tonnes/yr of softwood market pulp. The first board machine arrived in 1950 followed by a second pulping line in 1976. The company was quick to expand its operations and built another pulp mill at Tainionkoski in 1961 with an additional board machine in 1965.

Improving with age

Some 70 years after the original site was taken over by Enso, Imatra Mills' total paper and board production capacity amounts to 1.125 million tonnes/yr. The Imatra Mills complex is part of Stora Enso's packaging board division, more specifically, the group's consumer packaging boards business. The mills produce liquid and food packaging boards, as well as other packaging and graphic boards.

Some 85% of Imatra's output is exported. The most important market is Europe, but a substantial share of Imatra's shipments also go to southeast Asia. The two mills use a total 4.0 million m3/yr of wood, divided equally between birch and pine. The spruce chips used by the chemi-thermomechanical pulp (CTMP) plant account for around 15%. Most of the wood is brought to the mills by rail and road and imported wood makes up roughly one third of the total.

The Imatra Mills sit nestled between the trees in eastern Finland

This year, Imatra Mills is undergoing yet another transition phase. Stora Enso has set aside a budget of around Euro 365 million ($333 million) for a project called Imatra Pulp 2001. The blueprint outlines five main areas for improvement, namely:

• wood handling
• fiber lines
• power plant
• pulp dryer
• Tainionkoski mill

Starting with woodhandling, Stora Enso's management put a new wood terminal at the top of its wish list. Around 95% of the site's wood is transported from Russia into Finland on railcars, but the top-loading Russian cars create handling difficulties when it comes to gaining access to the goods. As a result, the group is aiming to simplify the procedure by building a terminal close to Finland's border with Russia where the wood can be loaded into easily accessible side-loading railcars. As if that is not enough, Stora Enso's plan for the wood handling arena also includes installing a wood measuring station, new debarking line and new chip screening unit, as well as rebuilding Imatra's existing debarking line and chip storage unit. The new debarking line started up in March, while the rebuilt line is due to come back on stream in December 2002. "From the end of next year, there will be two identical lines in operation here," says Heikki Rutanen, director of Imatra Pulp 2001. Once the project is wrapped up, they will process 400 m3/hr of softwood and 280 m3/hr of hardwood from a total of 5.0 million m3/yr of wood. Tainionkoski will use just 700,000 m3/yr of the processed wood, while Kaukopää will consume a massive 4.2 million m3/yr. The mills' total wood consumption is set to rise by around 1.0 million m3/yr under the scheme.

Out with the old, in with the new

Imatra's home-produced woodchips are then transported to one of the site's fiber lines, which have also undergone a significant makeover in the last two years. The biggest part of the fiber lines project is the installation of a brand new production unit, pulp line #3. Erection of the line started in April 2000 and took just 12 months to complete. Fiber line #3 came on stream in April 2001, one month ahead of schedule. The new facility has a capacity of 600,000 tonnes/yr of bleached birch pulp. Kvaerner Pulping supplied the digester and diffuser for line #3, while Andritz-Ahlstrom fulfilled the rest of the order, which included oxygen bleaching and screening.

Rutanen picks out a couple of impressive statistics regarding the new line. "The line has just one screen for its output of 2,000 tonnes/day," he says. "The continuous cooking process takes place in a digester that is 9.5 m wide and replaces a total of 10 old batch digesters," Rutanen continues. "It is the second biggest digester in the world," he adds.

Kaukopää's control room is the brain behind the smooth production process

But the prestigious new startup has done little to overshadow another phase in the fiber line part of the Imatra project. As well as adding one large new line to the group's list of assets, Stora Enso also forged ahead with a rebuild of pulp line #2 at Kaukopää. The upgrade started as soon as production on line #3 got underway and took two months to complete. Work on the existing unit was focused on switching production on line #2 from hardwood to softwood pulp with Andritz-Ahlstrom as the main supplier. The facility formerly manufactured bleached birch pulp, but it can now produce up to 250,000 tonnes/yr of bleached pine and spruce pulp instead.

Stora Enso is certainly lavishing a lot of time and money on the Imatra Mills to ensure that the site remains competitive and profitable in the future, but there is one element that has been left out of the equation - pulp line #1. While suppliers, engineers and mill employees were celebrating the successful startup of Kaukopää's third fiber line along with the completion of rebuilding line #2, there may have been a few others who took a minute to say goodbye to the end of an era. Pulp line #1, which is around 50 years old, was shut down in June 2001. The 180,000 tonne/yr bleached pine pulp unit is being dismantled over the next couple of years. The unit's machinery cannot be used as spare parts for other Stora Enso facilities as it is not compatible with the firm's equipment. The group says that it may sell off the old line if a buyer comes forward, but this is unlikely due to the age of the line. There is also an environmental aspect to consider. Line #1 was simply too old to meet "green" requirements in terms of emissions, for example, and Imatra Mills was given until September 1, 2001, to close the facility.

Computerized calm

On a positive note, the Kaukopää mill has been propelled into the age of automation and process control by cutting away the dead wood. The sites have been using control rooms for a number of years, but these have been given a boost with the new projects. Earlier, each pulp line was run via 15 m long control panels, which were located next to the machines. Times have changed, though. Fiber lines #2 and #3 are closely monitored from a remote on-site control room, which contains around 15 computer screens. Large numbers of employees previously found themselves working a full shift standing next to a hot, noisy, steaming hulk of machinery, faced with hundreds of buttons each with a specific purpose. Now there are just two people present in the control room, which has the same cool, airy atmosphere as a library. "There are no switches to start up or shut down the equipment now," Rutanen says. "It is all done by computers and is all integrated," he comments. An Alcont TPS system from Honeywell is installed to keep a close watch on the two lines.

With an output of over one million tonnes/yr in each division - pulp, paper and paperboard - it stands to reason that the Imatra Mills require a substantial amount of energy to keep them running. In line with the improvement and expansion in the site's other facilities, Stora Enso has also invested in the mills' power plant. Under the power part of the scheme, work included:

• increasing capacity in chemical cleaning of water
• installing a new feed water plant
• erecting a new tall oil plant
• implementing another system for burning malodorous gases
• buying a new electrostatic precipitator for the site's smaller recovery boiler
• making changes to the steam distribution.

The power project was completed earlier this year. As well as supplying the Imatra Mills with electricity, steam and water, the power plant is an important link in the chain of recycling the cooking chemicals. The organic matter, or lignin, dissolved from the wood is combusted in the power plant. The cooking chemicals are converted into white liquor, which is suitable for reuse in the cooking process. The electricity produced by the Imatra Mills amounts to some 700 GWh/yr, or around 60% of the electricity needed to run the plant. The site's own energy production is 100% back-pressure energy, while heat consumption is 550,000 tonnes/yr converted into oil. Black liquor and wood-based fuels account for 85% of fuel consumption and natural gas for the rest. Oil is only used as a reserve, according to the company.

Energy from the power plant is also used to keep the site's new pulp dryer up and running. Kvaerner Pulping, Andritz-Ahlstrom and Metso Chemical Pulping played key roles in supplying the 3.2 m wide unit, which stands on a piece of land where part of the lake used to be. "We had to fill in this area to build the pulp dryer. We had no other way of expanding," Rutanen comments. The dryer has a capacity of 1,000 tonnes/day of chemical pulp and 700 tonnes/day of CTMP. Rutanen explains that it was necessary to build the new dryer as the decision was taken to supply the Tainionkoski mill with pulp from Kaukopää. Along with the installation, Stora Enso has also expanded the location's pulp storage area. "We used to buy 120,000-140,000 tonnes/yr of pulp from Enocell," Rutanen says. "Imatra was one of the biggest buyers of pulp as well as one of the biggest producers. We need our own pulp production and stocks to supply the board machines and to keep quality consistent throughout the mill. We will stop buying pulp now," he concludes.

Imatra Mills' Capacity Increase 1999-2002   1999 2002 Wood use (m3/yr) 3.9 million 4.8 million Fiber production (tonnes/yr)     Bleached softwood pulp 181,000 250,000   Bleached birch pulp 404,000 600,000   Unbleached softwood pulp 156,000 170,000   CTMP 84,000 200,000 Purchased pulp (tonnes/yr) 117,000 0 Board production (tonnes/yr)     BM 1 131,000 160,000   BM 2 183,000 190,000   BM 4 220,000 250,000   BM 5 215,000 220,000 Paper production (tonnes/yr)     PM 6 69,000 75,000   PM 7 20,000 25,000   PM 8 185,000 210,000 Plastic coating on board (tonnes/yr) 246,000 270,000 Energy     Fuels as oil equivalent (tonnes/yr) 620,000 730,000   Share of own wood-based fuels 83% 85%   Electricity (GWh/yr) 1,300 1,600   Own production 60% 55%

Spreading the load

So far, the bulk of Stora Enso's budget for the Imatra Pulp 2001 project has been spent at Kaukopää. But Tainionkoski has not been left out in the cold. Plans for the neighboring site focus on pulp washing facilities, a rebuild of the cooking department and chip handling, as well as a rebuild of BM 5.

The revamp of the board machine is due for completion this month when the unit's capacity is set to rise from 220,000 tonnes/yr to 235,000 tonnes/yr of liquid packaging board. Voith Paper is providing equipment for the upgrade in an order valued at Euro 16 million. Andritz-Ahlstrom is supplying new washers and rebuilding the site's screening plant.

BM 5 is the second Imatra board machine that Stora Enso has rebuilt recently. At the end of last year, the company finished off a rebuild of BM 4 at Kaukopää. Work included an upgrade of the unit's wet end and a revamp of the machine's drives. Metso Paper was the main supplier. The aim of the Euro 37 million investment was to improve printability, product quality and production efficiency, according to the company. BM 4's capacity is set to rise from 220,000 tonnes/yr to 250,000 tonnes/yr by the end of 2002.

The story does not end here, either. Following completion of the extensive Imatra Pulp 2001 project, observers may expect Stora Enso to leave Imatra alone for a while to allow the dust to settle. But the industry could be in for a surprise sooner rather than later. "We still have room for a capacity increase of around 100,000 tonnes/yr," Rutanen says. But as to the timing and nature of the rise, his lips are sealed.