Valmet Technology Plays Key role at Metsä’s New Äänekoski Bioproduct Mill

Metsä Group's bioproduct mill in Äänekoski, Finland, was started up on Aug. 15, 2017. Valmet's delivery to the mill included a recovery boiler, pulp drying line, gasification plant, lime kiln, sulfuric acid plant, and mill-wide Valmet DNA automation system. 

All of the equipment delivered by Finland-based Valmet represents the latest technology and is highly energy-efficient. The gasification technology and recovery boiler will maximize the use of bioenergy and make the pulp mill totally fossil fuel-free. The recovery boiler, pulp drying line, and lime kiln are the largest in Europe. 

Construction of the mill was started in April 2015. The project proceeded as planned and was started up exactly on schedule. Safety was one of the special focus areas in the project. Valmet also emphasized safety onsite with special HSE experts and in contractor cooperation. As a result, Valmet's safety performance onsite was on a very good level for a project of this magnitude. 

 

 

"This project has been important for us both from the technology and employment perspective. The majority of technology provided by Valmet was engineered and manufactured in Tampere, Jyväskylä, Ulvila, and Raisio. It is our pleasure to rise to the challenge, when a customer like Metsä Group is taking the industry forward with investments of this magnitude. Success in a project like this is made possible by close cooperation between the two parties. Our cooperation has been open and constructive, and we have worked together to find the right solutions," said Bertel Karlstedt, Valmet Pulp and Energy Business Line president. 

"We have a long experience of co-operating with Valmet in our pulp mills in Finland. Throughout the project, Valmet has been a good and innovative partner when building the world-class bioproduct mill in Äänekoski," said Timo Merikallio, project director, Metsä Group. 

The new bioproduct mill in Äänekoski is the largest investment of the forest industry in Finland. Metsä Group's total investment amounted to approximately EUR 1.2 billion. The mill will achieve its nominal capacity approximately a year after startup. The mill will produce 1.3 million metric tons of pulp per year, along with other bioproducts such as tall oil and turpentine. New bioproducts that already complement the product concept include product gas from bark, sulfuric acid from the mill's odorous gases, and biogas and biofuel pellets from sludge.

Physically the largest of the Valmet delivered equipment is the recovery boiler. The boiler is designed for a capacity of 7,200 metric ton of dry solids per day. The Äänekoski recovery boiler has multiple high-power features, including patented heat recovery from flue gas to combustion air, enabling the mill to produce 260 MW of electricity and sell 1.4 times more electricity to the grid than it needs for its own operation. 

The produced pulp is dried in the pulp drying line, where the pulp web is formed, pressed and dried before being cut into bales. 

Individual, 250 kg bales are wrapped and consolidated into 2,000 kg units for transportation.

Valmet DNA automation system is the process control and information system for the whole bioproduct mill, and has machine and drive controls for the drying machine. It is also possible to expand the system with additional control and Industrial Internet systems. 

At the biomass gasification plant, bark is dried using a patented double-layer drying process with material recirculation. Dried bark is gasified to make product gas, which is then used as fuel in the lime kiln. 

Active lime is regenerated in the lime kiln using biofuels. A stationary product cooler is setting new standards for recovering process heat. 

The sulfuric acid plant represents Valmet's latest innovations and has been specially developed for this kind of mill. The new technology, which produces sulfuric acid from odorous gases, will enable the bioproduct mill to be nearly self-sufficient in sulfuric acid. 

Metsä Group is a forerunner in sustainable bioeconomy utilizing renewable wood from sustainably managed northern forests. Metsä Group focuses on wood supply and forest services, wood products, pulp, fresh fiber paperboards and tissue, and cooking papers. Metsä Group's sales totaled EUR 4.7 billion in 2016, and it employs approximately 9,300 people. The Group operates in some 30 countries. 

Metsäliitto Cooperative is the parent company of Metsä Group and is owned by approximately 104,000 Finnish forest owners.