US 11,993,895 B2
Method of feeding wood chips to a prehydrolysis reactor
Marco Andrade, Curitiba (BR); Ronny Geiger, Curitiba (BR); Vesa Kaipainen, Kotka (FI); Auvo Kettunen, Kotka (FI); Petri Tarjavuori, Lappeenranta (FI); and Viridiane Vianna, Curitiba (BR)
Assigned to ANDRITZ OY, Helsinki (FI)
Appl. No. 17/282,451
Filed by ANDRITZ OY, Helsinki (FI)
PCT Filed Oct. 2, 2019, PCT No. PCT/FI2019/050706
§ 371(c)(1), (2) Date Apr. 2, 2021,
PCT Pub. No. WO2020/070389, PCT Pub. Date Apr. 9, 2020.
Claims priority of application No. 20185831 (FI), filed on Oct. 3, 2018.
Prior Publication US 2022/0002944 A1, Jan. 6, 2022
Int. Cl. D21C 1/06 (2006.01); D21C 3/24 (2006.01); D21C 3/26 (2006.01); D21C 7/06 (2006.01)
CPC D21C 1/06 (2013.01) [D21C 3/24 (2013.01); D21C 3/26 (2013.01); D21C 7/06 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method comprising:
feeding a slurry of chips and liquid to a prehydrolysis reactor in the production of dissolving pulp, in which method the slurry is pumped by using at least one pump to the prehydrolysis reactor,
feeding alkali into the at least one pump to increase a pH of the slurry to be in a pH range of 7 to 10 to reduce a pump wear rate of the at least one pump,
hydrolyzing the chips in the prehydrolysis reactor,
discharging the chips from the prehydrolysis reactor and feeding the chips to a continuous digester vessel;
cooking the chips in the continuous digester vessel to convert the chips to pulp, and
discharging the pulp from the continuous digester vessel.