New ultrafiltration technology saves fresh water at tissue mills
Valmet says its new ultrafiltration technology is a unique solution for decreasing tissue mills’ fresh water consumption.
The technology uses the tissue machine’s process water to produce ultrapure water: permeate. The permeate is used for the wire and press sections’ high-pressure showers instead of fresh water. Because the permeate is free from solid, turbidity and bacteria, it helps to maintain the performance and efficiency of the tissue machine.
The first prototype Valmet Ultrafiltration Tissue will be finalized and transferred to Essity’s tissue mill for test use during spring 2019.
Ultrafiltration is already being used at mills producing, for example, printing or packaging grades. For tissue mills, Valmet’s new cross-rotational ultrafiltration process is unique. “Using permeate instead of fresh water decreases the over-all water consumption in the tissue-making process and creates savings in the energy used for heating the fresh water. A modern tissue machine consumes 5–15 m3 of water per tonne of paper but our ultrafiltration technology saves fresh water at tissue mills by 1–2 m3,” explains Pasi Nurminen, technical product manager at Valmet.
Valmet has developed the ultrafiltration technology for tissue mills under the EU-funded project SpotView. Other members of the Finnish consortium are VTT Technical Research Centre of Finland, XerChem and the hygiene and health company Essity (formerly SCA).
The technology and its possibilities for purifying water in the tissue process have been verified at VTT’s laboratories.