EP0810321B1 - Procédé en discontinu pour préparation des pâtes kraft ameliorées - Google Patents
Procédé en discontinu pour préparation des pâtes kraft ameliorées Download PDFInfo
- Publication number
- EP0810321B1 EP0810321B1 EP97660041A EP97660041A EP0810321B1 EP 0810321 B1 EP0810321 B1 EP 0810321B1 EP 97660041 A EP97660041 A EP 97660041A EP 97660041 A EP97660041 A EP 97660041A EP 0810321 B1 EP0810321 B1 EP 0810321B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- liquor
- cooking
- uncausticized
- impregnation
- pulp
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Lifetime
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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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/0064—Aspects concerning the production and the treatment of green and white liquors, e.g. causticizing green liquor
-
- 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
- D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
-
- 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
- D21C3/22—Other features of pulping processes
Definitions
- the present invention relates to a process for preparing kraft pulp in which cellulosic material is treated with recycled pulping process liquids, uncausticized cooking liquor and causticized white liquor for dissolving the lignin therein. More particularly, the present invention relates to the use of green liquor or mother liquor from green liquor carbonate crystallization in early stages of modern displacement kraft batch cooking and the advantage thereof in terms of improved kraft pulp quality.
- green liquor the high level of carbonate and the low hydroxide concentration. Particularly important is to note that all reduced sulfur is already in the final and useful form of hydrosulfide, HS - ions (Na 2 S dissolved in water).
- the carbonate/hydroxide combination in green liquor does not provide the high pH necessary for the conventional kraft processes and must be converted to so called “white” liquor by a causticizing process, but it represents an excellent hydrosulfide source rich in alkalinity buffering carbonate.
- the sulfur species found in the spent black liquor can be impregnated into and reacted with the wood chips prior to finalizing the cooking with white liquor.
- the remaining mother liquor contains residual carbonate, but also all the sulfide originally present in the green liquor.
- This mother liquor has now found its new use directly, as such, in improving the displacement kraft batch cooking by introduction into the front-end of the cook. Earlier it has been suggested to causticize this mother liquor separately for preparing high sulfidity white liquor, but this would have further complicated the pulp mill process.
- a typical situation in a modern mill producing bleached kraft pulp would require the amount of green liquor for crystallization to be set to 20% of the total green liquor production after the recovery boiler (the remaining 80% were to be causticized conventionally to white liquor for cooking). This would generate pure caustic for bleaching, corresponding to 25 kg of NaOH per ton of oven-dry wood, i.e.
- a batch process for preparing kraft pulp from lignin-containing cellulosic material, said process comprising the steps of:
- FIG. 1 shows a block diagram of a kraft displacement batch cooking system.
- the figure defines the required tanks, streams and the cooking stage sequence.
- the kraft batch cook is started by charging the digester with wood chips and filling the digester with black liquor AA from the impregnation black liquor tank 5, soaking the chips.
- An overflow, A2 to the black liquor tank 4, point AB, is preferred in order to remove air and the diluted first front of liquor.
- the digester is pressurized and impregnation is completed.
- the cooking process is then continued by pumping in hot black liquor B from hot black liquor tank 1.
- the cooler black liquor A3, displaced by hot black liquor, is conducted to black liquor tank 4, point AB, discharging to an evaporation plant for recovery of cooking chemicals.
- the cooking sequence is continued by pumping hot white liquor C from tank 3 into the digester.
- the liquor D2, displaced by hot liquors above about the atmospheric boiling point, is conducted to hot black liquor tank 2.
- the digester temperature is close to the final cooking temperature.
- the final heating-up is carried out using direct or indirect steam heating and digester recirculation.
- the spent liquor is ready to be displaced with wash filtrate E.
- the first portion B1 of the displaced hot black liquor corresponds to the total of the volumes B required in the filling stages.
- the second portion D1 of displaced black liquor which is diluted by the wash filtrate E but is still above its atmospheric boiling temperature, is conducted to the hot black liquor tank 2, point D.
- the digester contents are discharged for further processing of the pulp. The above cooking sequence may then be repeated.
- the hot black liquor tank 2 provides cooled impregnation black liquor to tank 5, transferring its heat to white liquor and water by means of heat exchange.
- Tank 6 is provided for storage of green liquor or a derivative thereof, supplied from the cooking chemicals recovery plant.
- at least one of portions X1 - X3 of green liquor or its derivative are introduced in the impregnation and/or pretreatment stages.
- a volume X1 of 0.2 - 1.0 1 green liquor/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood is added from tank 6 into the impregnating warm black liquor AA from the tank 5, before carrying out impregnation using a temperature of between about 90 and 110 °C and a time of between about 30 - 60 min.
- a volume X2 of 0.2 - 1.0 1 green liquor/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood, is first added from tank 6 as such into the digester, followed by the warm black liquor AA for impregnation, and the impregnation is carried out using a temperature of between about 80 and 100 'C and a time of between about 30 - 60 min.
- the warm black liquor impregnation is carried out as described in the prior art, and then a volume X3 of 0.2 - 1.0 1 green liquor/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood is added from tank 6 into the hot black liquor B, and the hot black liquor treatment is carried out using a temperature of between 145 and 165 °C and a time between about 15 and 30 min.
- a volume X1 of mother liquor from green liquor crystallization, 0.06 - 0.4 l/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood, is added from tank 6 into the impregnating warm black liquor AA and the impregnation is carried out using a temperature of between about 90 and 110 °C and a time of between about 30 - 60 min.
- a volume X2 of mother liquor from green liquor crystallization, 0.06 - 0.4 l/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood, is first added from tank 6 as such into the digester, followed by the warm black liquor AA for impregnation, and the impregnation is carried out using a temperature of between about 80 and 100 'C and time of between about 30 - 60 min.
- the warm black liquor impregnation is carried out as described in prior art, and then a volume X3 of mother liquor from green liquor crystallization, 0.06 - 0.4 l/kg oven dry wood, corresponding to 0.15 - 0.7 mol HS - /kg oven dry wood is added from tank 6 into the hot black liquor and the hot black liquor treatment is carried out using a temperature of between 145 and 165 'C and a time between about 15 and 30 min.
- the uncausticized cooking liquor is added at the impregnation stage of the process, a higher temperature has to be used than in the prior art in order to use the chemicals effectively and to avoid too high a residual alkali concentration in the feed to the evaporation plant.
- the required higher impregnation temperature is achieved by using either digester recirculation and direct or indirect steam heating, or by co-adding a small amount of hot black liquor B from tank 1 into the impregnating black liquor AA.
- the temperature of this liquor is high enough to provide the desired reaction temperature.
- the principal advantage of the process of the present invention is that the "front-end" of the kraft displacement batch cooking is rendered more effective. This improves pulp quality, as digestion with white liquor in the "back-end” of kraft displacement batch cooking is greatly facilitated, requiring milder back-end cooking conditions and resulting in improved pulp quality in terms of pulp strength and easier bleaching of the pulp.
- EA Effective alkali NaOH + 1 ⁇ 2 Na 2 S, expressed as NaOH equivalents
- AA Active alkali NaOH + Na 2 S, expressed as Na 2 O equivalents
- a hot black liquor pre-treatment stage followed by introducing hot black liquor (HBL, 165 °C, 20 gEA/l) to the bottom of the digester displacing the spent impregnation black liquor out from the top of the digester (DWBL).
- hot black liquor stage hot white liquor (105 gEA(NaOH)/l; Sulfidity 40 %) charge was introduced to the bottom of the digester displacing the corresponding volume of spent hot black liquor out of the digester top (RHBL).
- a 25 minutes heating-up with circulation raised the temperature from 155 °C to the cooking temperature of 170 °C.
- terminal displacement was started by introducing washing buffer solution DL (0.02 Mol Na2CO3/1 + 0,05 Mol Na2S/l) into the digester bottom displacing the hot spent black liquor out of the digester top.
- the first displaced portion of the hot black liquor (HBL 1) covered the 17 1 volume needed for the next cook's hot black liquor charge.
- the second portion of the displaced liquor (BL 2) covered the 13 1 volume needed for getting the temperature down and for the next cook's impregnation liquor.
- the pulp was disintegrated, washed with deionized water, screened and analyzed. This cooking procedure was repeated three times by reclaiming the displaced liquors into the next cook.
- Bleaching chemicals demand for a given pulp brigtness was determined and the pulp strength measured by beating and testing.
- Bleaching process conditions are given in table E1.2.
- Cooking characteristics and results are given in table E1.3.
- Cooking Charge uncausticized cooking liquor, as (liquor-to-wood units) 0 as (TA, total alkali(NaOH)) 0 White liquor charge (EA, %(NaOH)) 20.7 H-factor 1006 Kappa number 20 Cooking residual (gEA(NaOH)/l) 20 Screened Yield (%) 43.6 SCAN Viscosity (ml/g) 1052 ISO Brightness (%) 34.0 Tear Index at Tensile Index 90 Nm/g (mNm 2 /g) 18.3 Bleaching Act.
- Cooking Charge uncausticed cooking liquor, as (liquor-to-wood units) 0.5 as (% TA, total alkali(NaOH)) 9 White liquor charge (EA, %(NaOH)) 17.1 H-factor 1008 Kappa number 20 Cooking residual (gEA(NaOH)/l) 20 Screened Yield (%) 43.4 SCAN Viscosity (ml/g) 1081 ISO Brightness (%) 34.0 Tear Index at Tensile Index 90 Nm/g (mNm 2 /g) 16.2 Bleaching Act.Chlorine consumption multiple for 89%(ISO) brightness, (kg act.Cl/(ODtonxkappa)) 3.7 Brightness ceiling (%ISO) 90.5 SCAN Viscosity at ISO89% Brightness (ml/g) 813 Tear Index at Tensile Index 90 Nm/g (mNm 2 /g) 16.4
- Example 1 The impregnation part of the process was carried out as described in Example 1, but the volume of WBL was 24 1.
- Table E4.1 lists the liquor volumes and conditions. Improved results with respect to reference example 1 are given in table E3.2. Liquor inputs and outputs and corrsponding cooking stage conditions in Example 4. Volumes in liters.
- Cooking Charge uncausticed cooking liquor, as (liquor-to-wood units) 0.5 as (% TA, total alkali(NaOH)) 9 White liquor charge (EA, %(NaOH)) 16.5 H-factor 1017 Kappa number 20 Cooking residual (gEA(NaOH)/l) 20 Screened Yield (%) 43.9 SCAN Viscosity (ml/g) 1088 ISO Brightness (%) 33.5 Tear Index at Tensile Index 90 Nm/g (mNm 2 /g) 15.8 Bleaching Act.Chlorine consumption multiple for 89%(ISO) brightness, (kg act.Cl/(ODtonxkappa)) 3.8 Brightness ceiling (%ISO) 90.3 SCAN Viscosity at ISO89% Brightness (ml/g) 786 Tear Index at Tensile Index 90 Nm/g (mNm 2 /g) 15.3
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- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Reinforced Plastic Materials (AREA)
- Secondary Cells (AREA)
Claims (6)
- Procédé par lots pour la préparation de pâte kraft à partir d'un matériau cellulosique contenant de la lignine, comprenant les étapes de :caractérisé en ce qu'il comprend en outre l'addition d'une quantité de liqueur non caustifiée avant l'étape d).a) remplissage d'un récipient contenant le matériau cellulosique avec une liqueur de cuisson épuisée ;b) imprégnation du matériau cellulosique par ladite liqueur de cuisson épuisée ;c) déplacement de ladite liqueur de cuisson épuisée utilisée pour l'imprégnation par un autre volume de liqueur de cuisson épuisée, et pré-traitement du matériau cellulosique ;d) déplacement de la liqueur de cuisson épuisée utilisée pour le pré-traitement par une liqueur de cuisson caustifiée, et cuisson jusqu'à un degré souhaité de délignification ;e) déplacement de la liqueur utilisée pour la cuisson par un filtrat de lavage ;
- Procédé selon la revendication 1, caractérisé en ce qu'une quantité de liqueur non caustifiée est ajoutée avant l'étape a).
- Procédé selon la revendication 1 ou 2, caractérisé en ce qu'une quantité de liqueur non caustifiée est ajoutée à la liqueur de cuisson épuisée introduite lors de l'étape a).
- Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce qu'une quantité de liqueur de cuisson non caustifiée est ajoutée à la liqueur de cuisson épuisée introduite lors de l'étape c) .
- Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que la quantité de liqueur de cuisson non caustifiée correspond à 0,2 à 1,0 litre/kg de bois séché en étuve.
- Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que la liqueur non caustifiée utilisée est une liqueur mère obtenue à partir de liqueur verte après cristallisation du carbonate qui y est contenu, et en ce que la quantité ajoutée correspond à 0,06 à 0,4 litre/kg de bois séché en étuve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI962260A FI105929B (fi) | 1996-05-30 | 1996-05-30 | Parannettu erämenetelmä sulfaattiselluloosan valmistamiseksi |
| FI962260 | 1996-05-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0810321A1 EP0810321A1 (fr) | 1997-12-03 |
| EP0810321B1 true EP0810321B1 (fr) | 2001-06-13 |
Family
ID=8546116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP97660041A Expired - Lifetime EP0810321B1 (fr) | 1996-05-30 | 1997-04-16 | Procédé en discontinu pour préparation des pâtes kraft ameliorées |
Country Status (16)
| Country | Link |
|---|---|
| EP (1) | EP0810321B1 (fr) |
| JP (1) | JPH1053989A (fr) |
| CN (1) | CN1109160C (fr) |
| AT (1) | ATE202167T1 (fr) |
| AU (1) | AU721440B2 (fr) |
| BR (1) | BR9703156A (fr) |
| CA (1) | CA2203096C (fr) |
| DE (1) | DE69705160T2 (fr) |
| ES (1) | ES2159385T3 (fr) |
| FI (1) | FI105929B (fr) |
| ID (1) | ID18445A (fr) |
| NO (1) | NO972456L (fr) |
| NZ (1) | NZ314898A (fr) |
| PT (1) | PT810321E (fr) |
| RU (1) | RU2128259C1 (fr) |
| ZA (1) | ZA973887B (fr) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6103057A (en) * | 1997-06-11 | 2000-08-15 | Fagerlund; Bertil K. | Kraft digesting process wherein a vapor interface is formed by withdrawing hot cooking liquor |
| FI120361B (fi) * | 2003-12-31 | 2009-09-30 | Gl & V Finance Hungary Kft | Eräkeittomenetelmä kraftmassan valmistamiseksi |
| US7867360B2 (en) * | 2004-07-13 | 2011-01-11 | Fpinnovations | Generation of active polysulphide with manganese and bismuth catalysts |
| JP5207191B2 (ja) * | 2006-05-19 | 2013-06-12 | ザ リサーチ ファンデーション オブ ステート ユニヴァーシティ オブ ニューヨーク | セルロース系材料の炭酸塩前処理およびパルプ化の方法 |
| SE0702874L (sv) * | 2007-12-20 | 2009-06-09 | Metso Fiber Karlstad Ab | Förfarande vid tillverkning av sulfatmassa där hemicellulosor återförs |
| PT2567023E (pt) * | 2010-05-04 | 2014-12-23 | Bahia Specialty Cellulose Sa | Método e sistema para a produção de pasta de dissolução com elevado teor alfa |
| RU2535804C2 (ru) * | 2010-05-04 | 2014-12-20 | Байа Спешалти Сельюлоз Са | Способ и система производства растворимой целлюлозной массы с высоким содержанием альфа-целлюлозы |
| KR20110123184A (ko) | 2010-05-06 | 2011-11-14 | 바히아 스페셜티 셀룰로스 에스에이 | 높은 알파 용해 펄프 제조를 위한 방법 및 시스템 |
| AU2010202496B2 (en) * | 2010-05-04 | 2015-04-16 | Bahia Specialty Cellulose Sa | Method and system for high alpha dissolving pulp production |
| EP2592186A1 (fr) * | 2011-11-08 | 2013-05-15 | Södra Cell AB | Procédé de réduction en pâte kraft |
| CN104452389B (zh) * | 2014-11-04 | 2017-02-15 | 中国轻工业南宁设计工程有限公司 | 一种节能的制浆蒸煮顺序联锁控制系统 |
| CN104988781B (zh) * | 2015-08-11 | 2017-01-18 | 湛江晨鸣浆纸有限公司 | 一种木片制浆工艺 |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3811995A (en) * | 1972-09-05 | 1974-05-21 | Westvaco Corp | Method of high yield semichemical pulp production |
| JPS55103386A (en) * | 1979-01-29 | 1980-08-07 | Sanyo Kokusaku Pulp Co | Two stage sulphate digesting method |
| JPS6059189A (ja) * | 1983-08-24 | 1985-04-05 | ベロイト コ−ポレ−ション | 多段式木材チツプ蒸解法 |
| SU1645323A1 (ru) * | 1989-04-05 | 1991-04-30 | Всесоюзное научно-производственное объединение целлюлозно-бумажной промышленности | Способ получени целлюлозы |
| FI92224C (fi) * | 1991-06-28 | 1994-10-10 | Sunds Defibrator Rauma Oy | Eräprosessi kraftmassan valmistamiseksi |
| GB9117936D0 (en) * | 1991-08-20 | 1991-10-09 | Canada Inc | Production of sodium hydroxide |
| SE500748C2 (sv) * | 1992-10-12 | 1994-08-22 | Bertil Pettersson | Förfarande vid kemikalieåtervinning i en sulfatmassafabrik för framställning av dels en vitlut med hög sulfiditet och dels en sulfidfattig vitlut |
| FI95608B (fi) * | 1994-06-17 | 1995-11-15 | Ahlstroem Oy | Menetelmä keittolipeiden valmistamiseksi viherlipeää kiteyttämällä |
| US5674359A (en) * | 1995-02-08 | 1997-10-07 | Ahlstrom Machinery Inc. | Continuous cooking of cellulosic fibrous material with cold alkali impregnation |
-
1996
- 1996-05-30 FI FI962260A patent/FI105929B/fi not_active IP Right Cessation
-
1997
- 1997-04-16 ES ES97660041T patent/ES2159385T3/es not_active Expired - Lifetime
- 1997-04-16 PT PT97660041T patent/PT810321E/pt unknown
- 1997-04-16 DE DE69705160T patent/DE69705160T2/de not_active Expired - Fee Related
- 1997-04-16 AT AT97660041T patent/ATE202167T1/de active
- 1997-04-16 EP EP97660041A patent/EP0810321B1/fr not_active Expired - Lifetime
- 1997-04-18 CA CA002203096A patent/CA2203096C/fr not_active Expired - Lifetime
- 1997-05-06 ZA ZA9703887A patent/ZA973887B/xx unknown
- 1997-05-09 AU AU20162/97A patent/AU721440B2/en not_active Ceased
- 1997-05-14 BR BR9703156A patent/BR9703156A/pt not_active IP Right Cessation
- 1997-05-21 ID IDP971703A patent/ID18445A/id unknown
- 1997-05-26 NZ NZ314898A patent/NZ314898A/en unknown
- 1997-05-29 CN CN97113050A patent/CN1109160C/zh not_active Expired - Fee Related
- 1997-05-29 RU RU97108781A patent/RU2128259C1/ru not_active IP Right Cessation
- 1997-05-29 NO NO972456A patent/NO972456L/no not_active Application Discontinuation
- 1997-05-30 JP JP9158156A patent/JPH1053989A/ja active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ATE202167T1 (de) | 2001-06-15 |
| NO972456D0 (no) | 1997-05-29 |
| AU2016297A (en) | 1997-12-04 |
| EP0810321A1 (fr) | 1997-12-03 |
| DE69705160T2 (de) | 2002-05-16 |
| RU2128259C1 (ru) | 1999-03-27 |
| CN1170795A (zh) | 1998-01-21 |
| FI962260A0 (fi) | 1996-05-30 |
| PT810321E (pt) | 2001-10-31 |
| CA2203096C (fr) | 2005-06-28 |
| CN1109160C (zh) | 2003-05-21 |
| NZ314898A (en) | 1998-06-26 |
| DE69705160D1 (de) | 2001-07-19 |
| ID18445A (id) | 1998-04-09 |
| FI962260L (fi) | 1997-12-01 |
| ES2159385T3 (es) | 2001-10-01 |
| ZA973887B (en) | 1998-02-25 |
| NO972456L (no) | 1997-12-01 |
| CA2203096A1 (fr) | 1997-11-30 |
| FI105929B (fi) | 2000-10-31 |
| AU721440B2 (en) | 2000-07-06 |
| JPH1053989A (ja) | 1998-02-24 |
| BR9703156A (pt) | 1998-10-27 |
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