SE9504147L - Method and apparatus for treating pulp - Google Patents

Method and apparatus for treating pulp

Info

Publication number
SE9504147L
SE9504147L SE9504147A SE9504147A SE9504147L SE 9504147 L SE9504147 L SE 9504147L SE 9504147 A SE9504147 A SE 9504147A SE 9504147 A SE9504147 A SE 9504147A SE 9504147 L SE9504147 L SE 9504147L
Authority
SE
Sweden
Prior art keywords
tower
pulp
treatment
acid
bleaching
Prior art date
Application number
SE9504147A
Other languages
Swedish (sv)
Other versions
SE9504147D0 (en
SE516693C2 (en
Inventor
Kaj Henricson
Original Assignee
Ahlstroem Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from SE9503696A external-priority patent/SE504078E/en
Application filed by Ahlstroem Oy filed Critical Ahlstroem Oy
Priority to SE9504147A priority Critical patent/SE516693C2/en
Publication of SE9504147D0 publication Critical patent/SE9504147D0/en
Priority to FI955879A priority patent/FI955879A/en
Priority to FI955878A priority patent/FI105701B/en
Priority to FI960214A priority patent/FI104574B/en
Priority to AU73016/96A priority patent/AU7301696A/en
Priority to DE69613989T priority patent/DE69613989D1/en
Priority to US09/051,678 priority patent/US6306253B2/en
Priority to PT96934841T priority patent/PT856080E/en
Priority to AT96934841T priority patent/ATE203291T1/en
Priority to BR9611258A priority patent/BR9611258A/en
Priority to PCT/FI1996/000552 priority patent/WO1997015713A1/en
Priority to ES96934841T priority patent/ES2158355T3/en
Priority to CA002235325A priority patent/CA2235325C/en
Priority to EP96934841A priority patent/EP0856080B1/en
Publication of SE9504147L publication Critical patent/SE9504147L/en
Priority to US09/793,652 priority patent/US20010020521A1/en
Publication of SE516693C2 publication Critical patent/SE516693C2/en

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

Pulp is treated in an acid tower at acidic pH and high temperature, and in a bleaching tower. Pulp dwell time and temperature are controlled during the acid treatment. A method for bleaching pulp comprises (a) cooking the pulp and optionally carrying out oxygen gas delignification to reduce the kappa value to less than 24 (14), and (b) carrying out an acid treatment. The acid treatment comprises (b') treatment with an acid in at least one acid tower at a pH of 2-5 and 75-130 degreesC to reduce the kappa value by 2-9 units, and (b'') treatment with one or more bleaching or treatment chemicals in at least one bleaching tower. Steps (b') and (b'') may be reversed and no washing is carried out in between these two steps. In order to prevent a significant reduction in pulp strength during step (b'), the dwell time (t) is 30-300 minutes and the treatment temperature (T) is greater than a minimum temperature (Tmin) and less than a maximum temperature (Tmax) defined by the following equations : Tmin = (10517/24 + 1n(2t)) - 273 Tmax = Tmin + 23 degreesC. Supply of pulp to and/or from the acid tower(s) is regulated in order to maintain uniform flow conditions in the tower(s) and keep the dwell time in the tower(s) substantially constant. An Independent claim is also included for the process apparatus.
SE9504147A 1995-10-20 1995-11-21 Acidic bleaching process for pulp, includes acid treatment step in tower under controlled pH, high temperature and dwell time conditions SE516693C2 (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
SE9504147A SE516693C2 (en) 1995-10-20 1995-11-21 Acidic bleaching process for pulp, includes acid treatment step in tower under controlled pH, high temperature and dwell time conditions
FI955879A FI955879A (en) 1995-11-21 1995-12-07 Procedure for bleaching of pulp
FI955878A FI105701B (en) 1995-10-20 1995-12-07 Method and arrangement for treatment of pulp
FI960214A FI104574B (en) 1995-10-20 1996-01-07 Method and apparatus for pulping
EP96934841A EP0856080B1 (en) 1995-10-20 1996-10-18 Acid treatment of pulp at high temperature in connection with bleaching
CA002235325A CA2235325C (en) 1995-10-20 1996-10-18 Acid treatment of pulp at high temperature in connection with bleaching
PT96934841T PT856080E (en) 1995-10-20 1996-10-18 ACUTE TREATMENT OF HIGH TEMPERATURE PAPER PASTE IN COMBINATION WITH BLEACHING
DE69613989T DE69613989D1 (en) 1995-10-20 1996-10-18 HIGH TEMPERATURE ACID TREATMENT OF FIBER WHILE BLEACHING
US09/051,678 US6306253B2 (en) 1995-10-20 1996-10-18 Acid treatment of pulp at high temperature prior to chlorine dioxide bleaching
AU73016/96A AU7301696A (en) 1995-10-20 1996-10-18 Acid treatment of pulp at high temperature in connection with bleaching
AT96934841T ATE203291T1 (en) 1995-10-20 1996-10-18 HIGH TEMPERATURE ACID TREATMENT OF PULP DURING BLEACHING
BR9611258A BR9611258A (en) 1995-10-20 1996-10-18 High temperature acid pulp treatment in connection with bleaching
PCT/FI1996/000552 WO1997015713A1 (en) 1995-10-20 1996-10-18 Acid treatment of pulp at high temperature in connection with bleaching
ES96934841T ES2158355T3 (en) 1995-10-20 1996-10-18 ACID TREATMENT OF PAPER PASTE AT HIGH TEMPERATURE IN RELATION TO WHITENING.
US09/793,652 US20010020521A1 (en) 1995-10-20 2001-02-27 Acid treatment of pulp at high temperature in connection with bleaching

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9503696A SE504078E (en) 1995-10-20 1995-10-20 Process and apparatus system for treating cellulose pulp with acid to reduce its kappa number
SE9504147A SE516693C2 (en) 1995-10-20 1995-11-21 Acidic bleaching process for pulp, includes acid treatment step in tower under controlled pH, high temperature and dwell time conditions

Publications (3)

Publication Number Publication Date
SE9504147D0 SE9504147D0 (en) 1995-11-21
SE9504147L true SE9504147L (en) 1997-04-21
SE516693C2 SE516693C2 (en) 2002-02-12

Family

ID=26662403

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9504147A SE516693C2 (en) 1995-10-20 1995-11-21 Acidic bleaching process for pulp, includes acid treatment step in tower under controlled pH, high temperature and dwell time conditions

Country Status (1)

Country Link
SE (1) SE516693C2 (en)

Also Published As

Publication number Publication date
SE9504147D0 (en) 1995-11-21
SE516693C2 (en) 2002-02-12

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Legal Events

Date Code Title Description
NUG Patent has lapsed