EP0977918B1 - A wood delignification chemical process using ammonium magnesium bisulphite as the active reagent - Google Patents

A wood delignification chemical process using ammonium magnesium bisulphite as the active reagent Download PDF

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Publication number
EP0977918B1
EP0977918B1 EP98914170A EP98914170A EP0977918B1 EP 0977918 B1 EP0977918 B1 EP 0977918B1 EP 98914170 A EP98914170 A EP 98914170A EP 98914170 A EP98914170 A EP 98914170A EP 0977918 B1 EP0977918 B1 EP 0977918B1
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EP
European Patent Office
Prior art keywords
acid
cooking acid
magnesium
bisulphite
ammonium
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Expired - Lifetime
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EP98914170A
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German (de)
French (fr)
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EP0977918A1 (en
Inventor
Joao Manuel Almeida Oliveira Baptista
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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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
    • D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites
    • D21C3/14—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites ammonium bisulfite
    • 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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
    • D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites
    • D21C3/10—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites magnesium bisulfite

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  • Paper (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)

Abstract

The present innovation consists of the use of a reagent solution (FINAL COOKING ACID) where ammonium magnesium bisulphite is the active chemical. This new process is particularly useful to those industrial plants where the cellulose pulp is obtained by the magnesium acid process. The present innovation consists of the introduction of ammonium ions in the cooking acid used in such plants (initial cooking acid). The final cooking acid is obtained by the reaction of the initial cooking acid with ammonium hydroxide. Experimental results show the superiority of the present innovation over the magnesium acid bisulphite pulping process which is expressed by production of cellulosic fibres with higher mechanico-physical index values, decrease in the percentage of uncooked material, increase in wood yield and less environmental impact.

Description

  • Several sulphite wood delignification process with industrial application have been known for a number of years. The distinction between them is based on the active chemical present in the reagent solution (cooking acid).
  • The compounds used as active chemicals are all monocationic bisulphites, mainly of calcium, magnesium, sodium or ammonium. The pulping process with calcium bisulphite is an exception, when dolomite is used to prepare the acid.
  • In the last 30 years the bisulphite cellulosic pulps have been losing competivness to KRAFT pulps, which are obtained by a chemical process in an alkaline medium.
  • The major disadvantage of bisulphite pulps is the weaker mechano-physical characteristics of their cellulosic fibres when compared with those obtained by the KRAFT process.
  • The present innovation refers to a chemical process for wood delignification and consists of the use of a reagent solution where ammonium and magnesium bisulphites are together the active chemicals.
  • The combination of both ammonium and magnesium cations as bisulphite is the novelty of this application
  • This new pulping process is particularly useful to those industrial plants where cellulose pulp is obtained by the magnesium acid bisulphite process.
  • The specific cooking acid of magnesium acid bisulphite pulping process is, physically, a gas-liquid system. The liquid phase is a magnesium bisulphite and sulphur dioxide aqueous solution in equilibrium with the SO2 gas phase. The system is kept at temperature and pressure values of about 50°C and 2 Kg cm-2, respectively.
    This particular cooking acid will be referred further on this document as the INICIAL COOKING ACID.
  • The basis of the present innovation is the inclusion of the ammonium ion in the initial cooking acid, as described by the following equation:
    Figure imgb0001
  • The cooking acid obtained by this reaction will be referred to in this document as the FINAL COOKING ACID.

            FINAL COOKING ACID composition: Mg(HSO3)2 + NH4(HSO3) + [SO2 =f(pH)]

  • The amount of SO2 stoichiometrically in excess is a function of pH.
  • The addition of ammonium hydroxide must drive the initial pH value of inicial cooking acid (1.5) to a final value between 2 and 4, depending on the needs of the process. This operation could be performed in a tank with the initial cooking acid under pressure (accumulator) or in the reactor (digester).
  • In the FINAL COOKING ACID the percentage of total SO2, free plus combined forms, must be kept within 4% to 7% , depending on the requirements of the process.
  • The pulping process operated at a higher pH value, such as that attained after ammonium hydroxide addition, decreases the wood degradation process, enables the production of cellulosic fibres with higher mechanico-physical index values, and decreases the specific consumption of wood.
  • On the other hand, the presence of ammonium ions accelerate the reaction process decreasing both wood chip impregnation time and percentage of uncooked material. This latter effect improves the wood yield of the process.
  • The experimental results obtained with hard wood, namely eucalyptus, show the superiority of the present innovation over the magnesium acid bisulphite pulping process, which is expressed by:
    1. a - Production of cellulosic fibres with a higher mechanico-physical index values.
    2. b - Decreased percentage of uncooked material.
    3. c - Increased wood yield.
    4. d - Less environmental impact.

Claims (1)

  1. Wood delignification process, applied to eucalyptus wood, characterized by the utilisation of a mixture of magnesium and ammonium bisulphite salts as the active chemicals, as follows:
    a) start from an initial cooking acid at pH 1.5, temperature of 50°C and pressure of 2 kg cm-2, with the following composition:

            Mg (HSO3)2 (aq) + SO2 (g) ;

    b) add ammonium hydroxide in order to obtain a final cooking acid with the following composition:

            Mg(HSO3)2 (aq) + NH4HSO3 (aq) + SO2 (g)

    with a pH between 2 to 4 and a concentration of total SO2 from 4% to 7%.
EP98914170A 1997-04-28 1998-04-20 A wood delignification chemical process using ammonium magnesium bisulphite as the active reagent Expired - Lifetime EP0977918B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
PT10199997 1997-04-28
PT101999A PT101999B (en) 1997-04-28 1997-04-28 CHEMICAL PROCESS OF DESLENHIFICATION OF WOOD USING AS AN ACTIVE REAGENT THE COMPOUND - DOUBLE BISCULPTURE OF MAGNESIUM AND AMMONIUM
PCT/PT1998/000002 WO1998049390A1 (en) 1997-04-28 1998-04-20 A wood delignification chemical process using ammonium magnesium bisulphite as the active reagent

Publications (2)

Publication Number Publication Date
EP0977918A1 EP0977918A1 (en) 2000-02-09
EP0977918B1 true EP0977918B1 (en) 2007-05-09

Family

ID=20085674

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98914170A Expired - Lifetime EP0977918B1 (en) 1997-04-28 1998-04-20 A wood delignification chemical process using ammonium magnesium bisulphite as the active reagent

Country Status (8)

Country Link
US (1) US20020153108A1 (en)
EP (1) EP0977918B1 (en)
AT (1) ATE362010T1 (en)
AU (1) AU738720B2 (en)
BR (1) BR9809423A (en)
DE (1) DE69837755T2 (en)
PT (1) PT101999B (en)
WO (1) WO1998049390A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR112013015190B1 (en) * 2010-12-15 2021-05-11 Imperial Innovations Limited method of treating a lignocellulose biomass to dissolve lignin in it and process of preparing glucose from a lignocellulose biomass
US11118308B2 (en) 2013-03-15 2021-09-14 Ip2Ipo Innovations Limited Treatment of lignocellulosic biomass with ionic liquid
GB201520453D0 (en) 2015-11-20 2016-01-06 Imp Innovations Ltd Process

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL87584C (en) * 1952-02-15
DE2445523A1 (en) * 1974-09-24 1976-04-01 Waldhof Aschaffenburg Papier METHOD FOR MANUFACTURING PULP
DD151581A3 (en) * 1976-11-11 1981-10-28 Kurt Doeink PROCESS FOR CLOSING LIGNOCELLULESIC MATERIALS AFTER THE BISULFIT PROCESS
JPS5653295A (en) * 1979-10-04 1981-05-12 Kogyo Gijutsuin Pulping method of waste rubber material
US4634499A (en) * 1983-05-02 1987-01-06 The Procter & Gamble Company Sulfite process for making pulp having a tactile softness from hardwood chips
SU1359387A1 (en) * 1985-09-25 1987-12-15 Центральный научно-исследовательский институт бумаги Pulp for making corrugated paper
SU1696631A1 (en) * 1989-06-26 1991-12-07 Сибирский научно-исследовательский институт целлюлозы и картона Solution for treating wood pulp

Also Published As

Publication number Publication date
DE69837755D1 (en) 2007-06-21
AU738720B2 (en) 2001-09-27
DE69837755T2 (en) 2008-01-31
WO1998049390A1 (en) 1998-11-05
EP0977918A1 (en) 2000-02-09
PT101999B (en) 2003-09-30
US20020153108A1 (en) 2002-10-24
BR9809423A (en) 2000-06-13
PT101999A (en) 1998-11-30
AU6858698A (en) 1998-11-24
ATE362010T1 (en) 2007-06-15

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