D - Textiles – Paper – 21 – B
Patent
D - Textiles, Paper
21
B
D21B 1/12 (2006.01) D21B 1/16 (2006.01) D21D 1/30 (2006.01) D21D 5/00 (2006.01) D21D 5/02 (2006.01) D21C 9/16 (2006.01)
Patent
CA 2451155
There is a need for a cheaper method of producing bleached TMP and CTMP without impairing the properties of the pulp. This is made possible by the present invention, which relates to a method of producing said pulps in which finely divided lignocellulosic material is defibrated after pretreatment and the resultant pulp is bleached in the form of a suspension with bleaching agent that increases the anionic charge of the pulp fibres, whereafter the pulp suspension is cleaned and then possibly further treated, for instance bleached, characterised in that the defibration is effected with the aid of a) a refiner that has counter-rotating refining discs while using an extra high temperature (HTDD), or b) a refiner that has a single rotating refining disc(s) having a single refining zone or two parallel refining zones, while using an extra high temperature and while rotating the disc(s) at an extra high speed (RTS), and in that the cleaning treatment comprises first screeming the pulp suspension and them hydrocyclone cleaning said suspension, wherewith the reject obtained with each cleaning process is treated individually and the treated reject is returned to the advancing pulp suspension.
La présente invention concerne un procédé permettant la production à meilleur compte de PMT et de PCMT blanchie sans en compromettre les propriétés. En l'occurrence, après un traitement préalable, on procède au défibrage de la matière lignocellulosique finement broyée, puis on blanchit la pâte obtenue sous forme d'une suspension avec un réactif de blanchiment augmentant la charge anionique des fibres de la pâte. La suspension de pâte subit ensuite un nettoyage puis éventuellement un traitement adventif tel qu'un blanchiment. Ce procédé se caractérise en ce que, pour le défibrage on utilise a) un raffineur à disques contrarotatifs dans des conditions de température extra-haute, ou b) un raffineur à un ou plusieurs disques tournant dans un seul sens dans une seule zone de raffinage ou deux zones de raffinage parallèles dans des conditions de température extra-haute pour une vitesse de rotation extra-rapide. Ce procédé se caractérise également en ce que le nettoyage implique un premier criblage de la suspension de pâte suivi d'un traitement hydrocyclone de cette suspension, les rejets de chaque opération étant renvoyés dans la suspension de pâte en progression.
Engstrand Per
Jonsson Jonas
Sandberg Christer
Starck Goeran
Wahlgren Mikael
Holmen Aktiebolag
Macrae & Co.
LandOfFree
Method of producing bleached thermomechanical pulp (tmp) or... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing bleached thermomechanical pulp (tmp) or..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing bleached thermomechanical pulp (tmp) or... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1461748