EP 0517689 B1 19970716 - A method of producing kraft pulp
Title (en)
A method of producing kraft pulp
Title (de)
Ein Verfahren zur Herstellung von Kraftpulpe
Title (fr)
Un procédé de fabrication de pâte kraft
Publication
Application
Priority
- GB 9111256 A 19910524
- US 75684991 A 19910910
- US 78815191 A 19911105
Abstract (en)
[origin: EP0517689A1] Paper pulp (e.g. kraft pulp or sulfite pulp) is produced utilizing at least two different supplies (35, 41) of cooking liquor (e.g. white liquor), having different percentages of lignin reaction enhancing or carbohydrate degradation slowing chemicals (e.g. one having low sulfide content, and the other high sulfide content). The high sulfide content supply is typically used to impregnate the pulp (in 37), while the second supply is used in other cooking stages (e. g. digester 12), whether co-current or countercurrent. At least 60% of the sulfide of the cooking chemicals may be provided in the first supply (35). Some of the sulfide in the first supply is desirably provided in the form of polysulfide or elemental sulfur. When about 2% polysulfide on wood is utilized yield is significantly increased. Utilizing multiple chemical (e.g. sulfide) content supplies results in an optimum viscosity/kappa ratio and/or pulp strength properties for the pulp produced. <IMAGE>
IPC 1-7
IPC 8 full level
D21C 3/02 (2006.01); D21C 3/26 (2006.01); D21C 7/14 (2006.01); D21C 11/00 (2006.01)
CPC (source: EP)
D21C 3/022 (2013.01); D21C 3/26 (2013.01); D21C 11/0064 (2013.01)
Citation (examination)
- WO 9213994 A1 19920820 - AHLSTROEM OY [FI]
- SE 8802129 A
- Tappi, vol. 62, no. 7, July 1979, Atlanta, US, pages 49-51, Nordén S. et al
- Casey, J.P., "Pulp and Paper; Chemistry and Chemical Technology - 3rd edition, vol. I", 1980, John Wiley & Sons, Inc., New York, pages 470-476.
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IT LI LU MC NL PT SE
DOCDB simple family (publication)
EP 0517689 A1 19921209; EP 0517689 B1 19970716; AT E155540 T1 19970815; DE 69220853 D1 19970821; FI 921254 A0 19920324; JP H05163690 A 19930629; NO 920692 D0 19920221; NO 920692 L 19921125
DOCDB simple family (application)
EP 92890125 A 19920525; AT 92890125 T 19920525; DE 69220853 T 19920525; FI 921254 A 19920324; JP 12203692 A 19920514; NO 920692 A 19920221