US 12,291,820 B2
Process for manufacturing a fibre web
Marko Kolari, Espoo (FI); Jaakko Ekman, Espoo (FI); and Anu Jaakkola, Espoo (FI)
Assigned to Kemira Oyj, Helsinki (FI)
Appl. No. 17/786,723
Filed by Kemira Oyj, Helsinki (FI)
PCT Filed Dec. 18, 2020, PCT No. PCT/FI2020/050854
§ 371(c)(1), (2) Date Jun. 17, 2022,
PCT Pub. No. WO2021/123504, PCT Pub. Date Jun. 24, 2021.
Claims priority of application No. 20196109 (FI), filed on Dec. 19, 2019.
Prior Publication US 2023/0031382 A1, Feb. 2, 2023
Int. Cl. D21H 21/36 (2006.01); D21C 5/00 (2006.01); D21C 9/16 (2006.01); D21D 5/28 (2006.01)
CPC D21H 21/36 (2013.01) [D21C 5/005 (2013.01); D21C 9/163 (2013.01); D21D 5/28 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A process for manufacturing a fibre web, which process comprises:
a fibre stock preparation stage, where bleached cellulose-containing fibres are suspended into process water in order to prepare a fibre stock, which comprises an amount of the residual hydrogen peroxide, and
at least one pulp storage tower through which the fibre stock is transferred before the fibre stock is formed into a fibre web and dried, wherein
zinc ions are introduced to the fibre stock or one of its constituents to maintain the amount of residual hydrogen peroxide in the fibre stock at or above a predetermined threshold level after at least one pulp storage tower, and the amount of residual hydrogen peroxide is determined at least in one process location between the introduction of the zinc ions and the formation of the fibre web, and the determined amount is used to control the introduction of the zinc ions.