As biobased fuel, black liquor is a unique byproduct from pulp production with planet+ impact. Alfeld Mill in Germany engineered a solution involving the evaporation of spent black liquor that makes better use of this side stream for the mill’s power production. The move increased pulp production by 6,000 tons in 2021, which also translates to less transport emissions from pulp purchased on the market.
With a digester cooling project in 2021, engineers at Ehingen Mill in Germany are implementing a solution to recover heat during the cooling of the digesters to be reused in the pulping process. The energy the mill gains from cooling will be used to pre-heat the acid used in this operation, leading to an anticipated energy savings of 16,000 MWh per year. Other eco-effective benefits are achieved by reducing the use of sulphur dioxide (SO2) and hydrogen peroxide (H2O2), reducing chemicals entering the wastewater treatment system.
Powering Stockstadt Mill in Germany with ‘clean’ steam requires fresh energy input to heat the water from the river nearby. With a custom heat exchanger installed in 2021, the mill now recovers heat from other processes to warm the fresh water entering the system. This amounts to 14,000 MWh of recovered clean steam for use in their operations. In another eco-effective win, the temperature of the wastewater is also reduced which supports its re-entry into the river Main.
The Austrian city of Graz nearby Gratkorn Mill is warming up with planet+ heat from Sappi. Instead of going to waste, we’re supplying excess heat from our mill to the city via nine kilometres of underground pipes. During 2021 an expansion of heat delivery was agreed, and state-of-the-art heat pump technology was installed that enables a higher proportion of low- temperature heat sources. Together with our project partner, this impact is made possible thanks to €30 million in investments concluded in 2021. Today, the mill supplies 15% of Graz’s heat demand with the potential to grow to 25%.
Carmignano Mill in Italy began upgrading its cogeneration plant in 2021 with eco-effective technology that ambitiously strives to cover the mill’s total energy needs. The installation of state-of-the-art technology allows for more efficient extraction of energy from the same amount of fuel. The technology also enables us to capture energy contained in low-energy water used to dry sludge waste, considerably reducing waste sent to landfills. The equipment is also future-proofed to integrate with next-generation fuels such as green hydrogen and bio-methane.