The kraft pulp process
Each day of the year, the equivalent of 130 logging trucks of timber is unloaded in the timber yard from trains, boats and logging trucks.
The timber is debarked and chopped into wood-chips, which are stored in separate piles depending on the wood type. This makes it possible to manufacture pulp that is adapted to the specific quality requirements of the customer.
The chips are cooked in a continuous digester, drained, screened and washed before bleaching with oxygen, peroxide and ozone. It is bleached from 80 to 90 percent ISO brightness and becomes white and free from impurities. The pulp is bleached in a TFC process (Totally Chlorine Free), which is conducted without the addition of any chlorine chemicals.
The bleached pulp is then dried in a sheet-drying machine or in a flash dryer. Subsequently, the dried pulp is packed in bales, wrapped and transported with trucks to the Environmental friendly logistics terminal for onward transport with boat, train or truck to our customers.
The liquor from the digester (black liquor) contains spent chemicals and dissolved wood residues. The black liquor is transferred to the evaporator, where the dry content is increased before it is burned in the soda recovery boiler. The chemicals are recovered in the soda recovery boiler and the wood residues are converted into heat for the production of steam. The final processing of the chemicals takes place in the causticising department and new white liquor is formed, which is used in the digester, and the circle is completed.
The high-pressure steam that is produced in the Recovery Boiler is reduced in a turbine for green electricity production. Steam with a lower pressure is used in the manufacturing process. In addition, excess heat can be used for heating the premises. SCA Östrand also supplies heat to the Timrå Municipality district-heating network.