Advanced technology provides flexibility for the future at Arctic Paper
Arctic Paper Munkedals AB is one of Europe’s leading manufacturers of uncoated paper. Since a couple of decades back the company is on a mission – to become a leader in the sustainability field as well. An important step is being taken right now, with the construction of a new energy plant that will reduce CO2 emissions by 30,000 tonnes by 2022. This is the second part of the series of articles about Adven’s and Arctic Paper’s path towards tomorrow’s sustainable paper production – where we take a closer look at the technology behind the transition in Munkedal.
Sustainable transition in practice: Part 2
Munkedal, 100 kilometers north of Gothenburg, is the home of the paper mill Arctic Paper Munkedals AB. Currently, Adven and Arctic Paper are working to restructure the mill’s energy production – starting 2022, the steam production will be run almost entirely with recycled fuels. To achieve this, Adven has designed a tailor-made solution that uses proven technology in new ways.
Recycled wood, paper and plastic from industries and other businesses are among the fuels that will be used to operate Arctic Paper Munkedal’s new energy plant. This means the boiler will give new life to waste that cannot be recycled.
One of the main criteria when choosing the technical equipment, therefore, has been its ability to handle complex and varied fuels. Another requirement has been that it should be possible, without major investments, to adapt the boiler to other fuels such as biofuels.
In practice, this means that there have been two alternatives; grate or fluidized bed.
“In addition to fuel flexibility, it has been important to guarantee as high availability as possible. With these things combined, we have seen that a grate fired boiler provides the best conditions. The goal is for the plant to be in operation for around 8500 hours a year, which places very high demands on short maintenance stops. We will have two operations managers during the day, but also monitoring from both Arctic Paper and remotely from Adven’s control room.”
Recovering energy from waste requires efficient purification of flue gases in order to minimize emissions of, among other things, nitrogen and sulfur oxides into the atmosphere.
The purification of the flue gases in Arctic Paper’s new plant will be a five-step process:
- First, nitrogen oxides are handled in the boiler through a Selective Non-Catalytic Reduction system (SNCR).
- The exhaust gases from the boiler pass through a pre-separator. Sparks that can cause damage to subsequent cleaning steps are separated from the flue gas.
- To reduce the amount of mercury and acidic components such as sulfur oxides (SOx), hydrochloric acid (HCL) in the emissions, activated carbon and hydrated lime (PCDD) are then added. The contaminants react with the additives and are then separated along with the ash in the textile filter downstream. The filter residue material is then sent out to a storage silo.
- Downstream of the filter there is the flue gas fan and after this a quench system for cooling, that lowers the flue gas temperature from 150 ° C to 60 ° C.
- The final stage before the flue gases passes out through the 80-meter-high chimney is a wet scrubber. Here, gaseous contaminants that have not been deposited in the fabric filter, are cleaned so that the right emission values can be achieved. In order to be able to validate the values, a system for continuous measurement of emissions in the chimney is also installed.
A pipe bridge, measuring approximately 300 meters, will connect the energy plant with the mill, where saturated steam of nine bar will be transported to Arctic Paper. The remaining process water after the scrubber will be treated in Arctic Paper’s water treatment plant.
Tailor-made facility from the start
The site work phase is estimated to last for about twelve months from start was until the plant starts running. To succeed, Adven and Arctic Paper have designed a unique project approach where Adven collaborates closely with local and international partners.
Anders Hed adds that the physical limitations have affected the project’s structure:
“We have a limited area to work on, so it is very important to do the right things at the right time to simplify logistics. One of our most important tasks is to anticipate as many potential challenges as possible already in the pre-design”, says Anders Hed.
This, anticipating and managing new challenges that arise along the way is an inevitable part of developing technology at the forefront, says Raine Lampio – and part of the charm.
The technology in brief:
- A 30-megawatt fired boiler fueled by industrial and operational waste that produces 24 bars of saturated steam for Arctic Paper.
- A flue gas cleaning system consisting of a pre-separator, a fabric filter and a wet scrubber.
- Pre-separator: Separates harmful sparks from the flue gases.
- Fabric filter: Baghouse filter where various components are added, such as lime and carbon, which react with the flue gases and cause the hazardous substances to sink to the bottom and blend with the ash.
- Scrubber: In the last step, a scrubber is used to wash and take care of the harmful particles from the flue gases.
- Dirty process water is treated locally at Arctic Paper’s own treatment plant.