Finland-headed energy and forest industry technology major Valmet Oyj has announced that it will deliver a new ash crystallization plant for the Mercer Stendal pulp mill in Arneburg, Germany. This investment is part of Mercer’s long-term vision to further reduce the mill’s emissions and improve its performance. Ash crystallization plant contributes to this target by helping to close the mill’s chemical circulation, reducing the need for make-up chemicals, and by helping to extend the recovery boiler maintenance intervals to 24 months and beyond.
Mercer Stendal is part of North American Mercer International Group, a forest products company with operations in Germany, Canada, and the United States.
In Stendal, Mercer operates one of Europe’s most modern pulp mills and implements a biorefinery concept where wood is used extensively for pulp, bioenergy, and biochemicals, such as tall oil, turpentine, and methanol.
Since the mill started up in 2004, we have systematically invested in improving its performance and sustainability. Our sustainability efforts are guided by the Mercer vision and values and our long-standing philosophy of responsible business practices that encompass sustainability, safety, financial responsibility, and strong leadership. The new ash crystallization plant will help us to further improve both operational and environmental performance. We chose Valmet to deliver this project based on both their technical expertise and our previous joint projects, said Dr Martin Zenker, Mill Manager, Mercer Stendal.
Increase circularity and recovery boiler availability
The ash crystallization plant will recover valuable sodium salts and remove non-process elements, primarily chloride and potassium, from the mill’s liquor cycle.
This reduces plugging and corrosion in the mill’s recovery boiler, which enables longer intervals between maintenance shutdowns, increasing the recovery boiler’s long-term availability.
Removing these non-process elements with Valmet’s Ash Crystallizer design eliminates the need for ash dumping, which in turn reduces wastewater and lowers costs through decreased make-up chemical demand.
This solution delivers clear environmental benefits by reducing associated emissions.
Process 140 tonnes of ash per day
The Valmet Ash Crystallizer plant will have the capacity to process 140 tonnes of ash per day.
Valmet’s delivery covers the complete plant with an extensive delivery scope, including electrical and instrumentation systems (E&I), steel structures, and erection.
Valmet also delivers an expansion of the existing mill-wide Valmet DNA automation system. The new plant will be integrated into existing mill operations, mainly to the evaporation plant.
We are committed to advancing circularity and resource efficiency. Delivering a new ash crystallization solution to an existing mill is very much in line with these targets and brings several operational and environmental benefits. This project showcases that the ash crystallization solution is not only suitable for new large mills but also brings significant benefits to existing mills. We truly value our cooperation with Mercer and the Stendal mill in finding long-term solutions to optimize the mill’s performance, said Claus Jensen-Holm, Director, White Liquor and Evaporation, Pulp Mills at Valmet.
The new crystallization plant, the value of which has not been disclosed, is scheduled to be started up during the fourth quarter of 2027.
