JPH0219236B2 - - Google Patents
Info
- Publication number
- JPH0219236B2 JPH0219236B2 JP56053770A JP5377081A JPH0219236B2 JP H0219236 B2 JPH0219236 B2 JP H0219236B2 JP 56053770 A JP56053770 A JP 56053770A JP 5377081 A JP5377081 A JP 5377081A JP H0219236 B2 JPH0219236 B2 JP H0219236B2
- Authority
- JP
- Japan
- Prior art keywords
- stage
- pulp
- bleaching
- washing
- backwater
- 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
Links
- 238000004061 bleaching Methods 0.000 claims description 58
- 238000005406 washing Methods 0.000 claims description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 24
- 239000000243 solution Substances 0.000 claims description 17
- 150000002978 peroxides Chemical class 0.000 claims description 16
- 238000004140 cleaning Methods 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 10
- 238000010790 dilution Methods 0.000 claims description 9
- 239000012895 dilution Substances 0.000 claims description 9
- 238000007670 refining Methods 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- 239000002351 wastewater Substances 0.000 claims description 3
- 238000007865 diluting Methods 0.000 claims description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 claims 1
- 229920002678 cellulose Polymers 0.000 claims 1
- 239000001913 cellulose Substances 0.000 claims 1
- 238000007599 discharging Methods 0.000 claims 1
- 239000011347 resin Substances 0.000 description 48
- 229920005989 resin Polymers 0.000 description 48
- 239000000126 substance Substances 0.000 description 21
- 229920001131 Pulp (paper) Polymers 0.000 description 16
- 238000002474 experimental method Methods 0.000 description 10
- 102100031260 Acyl-coenzyme A thioesterase THEM4 Human genes 0.000 description 8
- 101000638510 Homo sapiens Acyl-coenzyme A thioesterase THEM4 Proteins 0.000 description 8
- 239000007844 bleaching agent Substances 0.000 description 8
- 241000196324 Embryophyta Species 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 208000005156 Dehydration Diseases 0.000 description 6
- 230000018044 dehydration Effects 0.000 description 6
- 238000006297 dehydration reaction Methods 0.000 description 6
- 239000013505 freshwater Substances 0.000 description 5
- 238000003825 pressing Methods 0.000 description 5
- 238000011282 treatment Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000005185 salting out Methods 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000010411 cooking Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 241000218657 Picea Species 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000003134 recirculating effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
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
- D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Description
砕木パルプ、リフアイナーパルプ及びサーモメ
カニカルパルプ（所謂TMP）の如きさらしメカ
ニカルパルプ及び半化学サーモメカニカルパルプ
（所謂CTMP）、すなわち歩留りが90％以上のパ
ルプは、毛羽（fluff）やテイツシユの如きより
改質された衛生製品に導入されて来た、高い吸収
性を得るには樹脂の含量が低いことを必要とす
る。その様な最良品質に対しパルプのDKM抽出
物含量は0.2％以下でなくてはならない。
これは、パルプが種々の方法により各処理段階
間で実質的な水量で洗浄され、且つ過酸化物で漂
白されるオープン・システムに於いては比較的容
易に達成される。充分な水の供給がある時でも通
常のバツクウオーターシステムと協同する事は、
さらに可能であり、これは実用的な理由から非常
に一般的である。
樹脂は洗浄液には溶解せずに洗浄液中でコロイ
バ状又はより荒い粗粒として分散しており、この
場合、洗浄液はアルカリ性が好ましい。低濃度樹
脂状態のみである程度バツクウオーターを再利用
できるという可能性に関しては重大な懸念があつ
た。従つて、工業上の慣習は少なくとも総水量15
〜20m3ptm90以上消費するウオーター・システム
を閉鎖しない所望の製品を製造していた。より少
ない水の消費では、明らかに低樹脂含有量は維持
され得なかつた。
しかし、水の低消費は、特に廃水の浄化方法が
関係し、又同時に処理工程からの熱が回収される
時には重要な意味を持つ。加減調整による水消費
が10m3ptm90以下に減少し得る時興味ある結果が
得られる。
向流洗浄はよく知られており、種々の蒸解処理
からの濃縮廃液を回復させるため広く適用された
方法である。最も実質的に処理された物質は完全
に溶解された物質であり、これはそれ自体全く洗
浄の困難は生じさせない。ところが樹脂の豊かな
木材の硫酸塩パルプはある種の雰囲気下でコロイ
ド樹脂が塩析を起こし洗浄を困難にする。しか
し、この問題は、次に続く適正に改良された多段
階漂白処理に於いて比較的大量の水を消費する適
当な洗浄装置により残存樹脂を洗浄することで一
般的に解決される。メカニカルパルプ等の製造技
術と種々の蒸解処理からの廃水回収のための向流
洗浄方法とを直接結合することは自然なこととは
考えられていなかつた。なぜならば、メカニカル
パルプ製造時、パルプウエブを介してくり返し
過されるときに、比較的粗分散した樹脂がどのよ
うな挙動をするのか予言するのは難かしかつたか
らである。
しかし、今やケミメカニカルパルプの場合の樹
脂の特別な要求に対する条件が適用されれば、そ
の様な結果は可能であることが知見された。
CTMP等のメカニカルパルプは一般にやや酸
性又は自然の雰囲気下で離解されるが、これは繊
維暴露に関連した機械処理がそのために理想的で
ある時でさえ、安定した樹脂分散を持たらさな
い。例えば、その後に引き続くアルカリ性雰囲気
下の過酸化物漂白時に、アルカリ性雰囲気は樹脂
分散を容易にする。
それ自体有利である過酸化物溶液中の樹脂の低
含量レベルは、樹脂粒子の凝集の危険性を減退さ
せ、それによつて樹脂除去に対してより大きな安
定性を与えるために、前記二段階の処理の間で行
なわれる洗浄は非常に大きな意味を持つ。しか
し、水の消費を減退させ、且つより有効に漂白剤
を利用するために大きな意味を持つ漂白段階に於
いて、同時に漂白廃液を再循環する時、塩析濃縮
が驚くべき速さで得られる様である。従つて純水
に対し次第に鈍化するイオン強度を有する洗浄水
によつてこの様に塩析を起こした樹脂を比較的す
速く洗浄する事が重要である。洗浄は実質的に置
換により行なわれ、溶解された物質に対して高い
置換程度で推進され得る。最低の水の消費のため
には洗浄は過酸化物漂白段階の前及び過酸化物漂
白段階の後の一連の洗浄過程で行なわれるべきで
ある。
洗浄液は必然的に向流で流される。
許容され得る低樹脂含量を有するパルプはその
様な方法により非常に低い水の消費で製造される
ことが驚くべき事に知見された。
未さらしCTMPパルプは、約1.2％の樹脂を含
むトウヒチツプを亜硫酸ナトリウム溶液に含浸す
ることによりパイロツトプラントで製造された。
これによりチツプは絶乾チツプ１トンあたり約20
KgのNa2SO3を吸収した。チツプを蒸気で予め
110℃に加熱し、次にチツプ・リフアイナーでリ
フアイニングした。チツプ・リフアイナーの後で
パルプ濃度を測定したところ、約30重量％であつ
た。パルプを約４％のパルプ濃度に希釈し、次に
圧搾装置で30％のパルプ濃度に脱水した。圧搾後
のパルプの樹脂含量を分析した。
いくつかの実験が行なわれた。そこではリフア
イナー後で圧搾前のパルプを水又は水とバツクウ
オーターの混合物で希釈した。漸減する量の新し
い水とパルプを希釈するための漸増する量のバツ
クウオーターを利用して、システムの閉鎖程度を
高める事が出来た。
パルプの樹脂含量の分析からのパルプの樹脂含
量とシステムに供給された新しい水の量との間の
関係をパルプ１トンあたりの新しい水の量（m3／
ｔ）で表わし第１図に示した。
各々の実験で樹脂に対する物質収支を確立する
ことにより、リフアイニング後のバツクウオータ
ーに分散し、且つ脱水及び洗浄により除去され得
る樹脂の量と、この方法では除去され得ない樹脂
の量とを各々計算することが可能であつた。次の
結果が得られた。
Bleached mechanical pulps such as groundwood pulp, refined pulp and thermomechanical pulp (so-called TMP) and semi-chemical thermomechanical pulps (so-called CTMP), i.e. pulps with a yield of 90% or more, are more refined than fluff and textured pulps. High absorbency, which has been introduced into quality hygiene products, requires a low content of resin. For such best quality, the DKM extract content of the pulp should be less than 0.2%. This is relatively easily accomplished in open systems where the pulp is washed with substantial amounts of water between each processing stage by various methods and bleached with peroxide. Even when there is an adequate water supply, working with a normal backwater system is
It is even possible, and this is very common for practical reasons. The resin is not dissolved in the cleaning liquid but is dispersed in the cleaning liquid in the form of coloiva or coarser particles, and in this case, the cleaning liquid is preferably alkaline. There were serious concerns regarding the possibility of reusing backwater to some extent only in a low concentration resin state. Therefore, industrial practice is to reduce the total amount of water to at least 15
~20m 3 The desired product was manufactured without shutting down water systems consuming more than 90 ptm. Clearly, the low resin content could not be maintained with less water consumption. However, low water consumption has important implications, especially when wastewater purification methods are concerned and at the same time heat from the treatment process is recovered. Interesting results are obtained when the water consumption due to conditioning can be reduced to less than 10 m 3 ptm90. Countercurrent washing is a well-known and widely applied method for recovering concentrated effluents from various cooking processes. Most substantially treated materials are completely dissolved materials, which do not themselves pose any cleaning difficulties. However, in resin-rich wood sulfate pulp, the colloidal resin salts out under certain atmospheres, making cleaning difficult. However, this problem is generally solved by washing the residual resin in a subsequent suitably modified multi-step bleaching process by suitable washing equipment which consumes relatively large amounts of water. It has not been considered natural to directly combine production techniques such as mechanical pulping with countercurrent cleaning methods for wastewater recovery from various cooking processes. This is because it is difficult to predict how a relatively coarsely dispersed resin will behave when repeatedly passed through a pulp web during mechanical pulp production. However, it has now been found that such results are possible if conditions are applied to the special requirements of the resin in the case of chemical mechanical pulps. Mechanical pulps such as CTMP are generally disintegrated in a slightly acidic or natural atmosphere, which does not result in a stable resin dispersion, even when the mechanical treatment associated with fiber exposure is ideal for this purpose. For example, during subsequent peroxide bleaching under an alkaline atmosphere, the alkaline atmosphere facilitates resin dispersion. The low content level of resin in the peroxide solution, which is advantageous in itself, reduces the risk of agglomeration of the resin particles and thereby provides greater stability for resin removal. The cleaning performed between treatments is of great importance. However, salting-out concentration can be obtained surprisingly quickly when simultaneously recirculating the bleaching liquid during the bleaching stage, which has great significance for reducing water consumption and making more efficient use of bleaching agents. It's like that. Therefore, it is important to relatively quickly wash the resin that has undergone salting out in this way using washing water that has an ionic strength that gradually becomes weaker than that of pure water. Washing is effected substantially by displacement and may be driven by a high degree of displacement for dissolved substances. For minimum water consumption, cleaning should be carried out in a series of wash steps before the peroxide bleaching step and after the peroxide bleaching step. The cleaning liquid necessarily flows countercurrently. It has surprisingly been found that pulps with acceptably low resin contents can be produced by such a process with very low water consumption. Unbleached CTMP pulp was produced in a pilot plant by impregnating spruce chips containing approximately 1.2% resin in a sodium sulfite solution.
As a result, the chips are approximately 20% per ton of bone dry chips.
Kg of Na 2 SO 3 was absorbed. Steam chips in advance
It was heated to 110°C and then refined using a chip refiner. The pulp density was measured after chip refiner and was approximately 30% by weight. The pulp was diluted to a pulp consistency of approximately 4% and then dewatered in a press to a pulp consistency of 30%. The resin content of the pulp after pressing was analyzed. Several experiments were conducted. There, after the refiner and before pressing, the pulp was diluted with water or a mixture of water and backwater. The degree of closure of the system could be increased using decreasing amounts of fresh water and increasing amounts of backwater to dilute the pulp. The relationship between the resin content of the pulp and the amount of fresh water fed into the system from the analysis of the resin content of the pulp can be expressed as the amount of fresh water per ton of pulp (m 3 /
t) and shown in FIG. By establishing a mass balance for the resin in each experiment, calculate the amount of resin that will be dispersed in the backwater after refining and can be removed by dehydration and washing, and the amount of resin that cannot be removed in this way. It was possible to do so. The following results were obtained.
【表】
第１図で示された結果は本発明が基礎とする観
察の一つを説明する。未さらしCTMPパルプの
製造時に於いて、閉鎖を強化すると、木材樹脂が
溶解又は分散される量が次第に減少し、且つパル
プの樹脂含量が増大することになる。サーモメカ
ニカルパルプ製造に於ける類似の研究は同じ結果
を与えた。結果から、閉鎖が強化されるに伴ない
リフアイニングに於いて溶解又は分散された樹脂
の塩析が増大することが解釈され得る。パルプの
低樹脂含量を必要とする応用分野のための未さら
しケミメカニカルパルプの製造に於いては、シス
テムを厳重に閉鎖する事は以前から可能ではなか
つた。
上記のパイロツトプラントからのパルプは次に
アルカリ性過酸化物漂白に付され、これは次の様
な目的を有する。
―パルプの白色度を増大させる。
―パルプの樹脂含量を減少させる。
この実験は、圧搾後の未さらしTMP及び
CTMPパルプが新しい水又は漂白段階からのバ
ツクウオーターで希釈されるようにして行なわれ
た。漂白剤を約12％のパルプ濃度のパルプ懸濁液
に混合し、その後パルプ懸濁液を漂白塔に送つ
た。漂白後パルプは新しい水又はバツクウオータ
ーで４％のパルプ濃度に希釈し、その後約35％の
パルプ濃度に圧搾した。試料パルプの樹脂含量は
圧搾後に決定した。
下の表は漂白実験で使用されるパルプのいくつ
かの例を示している。表は又漂白段階で使用され
た化学薬品投入量を含む。TABLE The results shown in FIG. 1 illustrate one of the observations on which the present invention is based. In the production of unbleached CTMP pulp, increasing closure will progressively reduce the amount of wood resin dissolved or dispersed and increase the resin content of the pulp. Similar studies in thermomechanical pulp production gave the same results. The results can be interpreted as increasing the salting out of the dissolved or dispersed resin during refining as the closure is strengthened. In the production of unbleached chemical mechanical pulp for applications requiring low resin content of the pulp, it has not previously been possible to tightly close the system. The pulp from the above pilot plant is then subjected to alkaline peroxide bleaching, which has the following objectives: -Increases the whiteness of the pulp. -Reducing the resin content of the pulp. This experiment consisted of unexposed TMP and
This was done so that the CTMP pulp was diluted with fresh water or backwater from the bleaching stage. The bleaching agent was mixed into the pulp suspension at a pulp concentration of approximately 12%, and then the pulp suspension was sent to the bleaching tower. After bleaching, the pulp was diluted with fresh water or back water to a pulp consistency of 4% and then pressed to a pulp consistency of approximately 35%. The resin content of the sample pulp was determined after pressing. The table below shows some examples of pulps used in bleaching experiments. The table also includes the chemical inputs used in the bleaching step.
【表】
漂白段階に於ける物質と樹脂の収支を確立する
ことにより、初期含有樹脂がどのくらい分散され
得たか、従つてどのくらい洗浄され得たか、ある
いは洗浄され得なかつたかを夫々ここでも又計算
する事が可能であつた。上記表に掲げたパルプの
結果は次の通りであつた。[Table] By establishing the substance and resin balance in the bleaching stage, it is again calculated how much of the initially contained resin could be dispersed and therefore how much could or could not be washed, respectively. It was possible. The results for the pulp listed in the table above were as follows.
【表】
漂白に於いて、残存する樹脂の主要部分が溶解
する。アルカリ性過酸化物漂白は、少なくとも閉
鎖が適当な制限内で行なわれるのでない時には強
化された閉鎖で沈殿、除去しないような形状で樹
脂を移行させる。CTMPパルプ１を用いた閉鎖
実験での水の消費量はパルプ１トン当たり約６〜
10m3に相当する。
さらしケミメカニカルパルプ製造の実験研究は
次の結果を示した。
１ 未さらしメカニカルパルプやサーモメカニカ
ルパルプや半化学サーモメカニカルパルプの製
造時において、木材の樹脂部分は溶解され、分
散される。分散された樹脂は洗浄によつて除去
され得る。
２ 未さらしパルプ用のバツクウオーターシステ
ムの閉鎖に於いては、常に小部分の樹脂が分散
される。未さらしパルプの樹脂含量はバツクウ
オーターの閉鎖を強化するとともに増加する。
３ これらのパルプの漂白段階において、樹脂は
樹脂の主要部分が分散される様な形状で移行さ
れる。樹脂は強化された閉鎖に於いて、沈殿し
ないように漂白時に改質される。
４ 過酸化物漂白されたさらしケミメカニカルバ
ルプに於ける分散し得ない樹脂量はパルプ量の
0.05〜0.15％のみである。
これらの発見によつてパルプが漂白前及び後に
洗浄され、且つバツクウオーターがパルプに対し
て向流で移動する時、低い水消費量で非常に低い
樹脂含量のさらしケミメカニカルパルプを製造す
ることを可能にする。
本発明の具体例が第２図で示される。もちろん
本発明はこの具体例に限定されるものではない。
チツプをリフアイナー段階１に供給する。そこ
でチツプを処理しなくても良く、蒸気処理及び／
又は化学薬品で含浸させても良い。リフアイナー
１の後にパルプを洗浄段階２に送る。これは洗浄
フイルターでも良いが、脱水又は洗浄圧搾が好ま
しい。パルプ懸濁液を洗浄段階前の漂白段階から
のバツクウオーター及び必要であるなら洗浄段階
２からのバツクウオーターで希釈する。
洗浄段階２の後の未さらしパルプに漂白剤及び
洗浄段階４から来る希釈水を供給し、漂白塔３に
送る。
漂白後、洗浄段階４からのバツクウオーターで
希釈し、洗浄段階４で洗浄する。洗浄及び脱水段
階５からのバツクウオーターは置換液として利用
する。パルプは脱水段階５で乾燥６前に脱水し、
この段階５は脱水又は洗浄圧搾が好ましい。バツ
クウオーターは洗浄段階２を経油してシステムか
ら離れる。洗浄液は洗浄段階５と連結して供給す
る。
その結果は次の様に説明され得る。
CTMPチツプを段階１でリフアイニングする。
リフアイナーの後のパルプ濃度は30％である。パ
ルプを脱水圧搾２で48％のパルプ濃度に脱水す
る。次にパルプを12％のパルプ濃度で漂白し、洗
浄フイルター４で洗浄し、最後に乾燥６の前に48
％のパルプ濃度に脱水圧搾５で脱水する。
オートメーシヨンモデル及び得られた実験結果
を用いて、システムに対する樹脂収支は異なる閉
鎖程度に於いて計算される。
システムから流出するバツクウオーターと漂白
段階において溶解又は分散される樹脂の洗浄有効
度とさらしパルプ中の樹脂含量との間の次の様な
関係が得られた。漂白段階の後のパルプ中の未分
散の樹脂含量は0.13％と仮定する。リフアイニン
グの後のパルプ中の樹脂含量は0.9％と仮定する。[Table] During bleaching, the main portion of the remaining resin is dissolved. Alkaline peroxide bleaching causes the resin to migrate in such a form that it will not precipitate and be removed with enhanced closure, at least unless closure is performed within appropriate limits. Water consumption in closed experiments using CTMP pulp 1 is about 6 to 1 ton of pulp.
Equivalent to 10m3 . Experimental research on bleached chemi-mechanical pulp production showed the following results. 1. During the production of unbleached mechanical pulp, thermomechanical pulp, and semi-chemical thermomechanical pulp, the resinous portion of wood is dissolved and dispersed. The dispersed resin can be removed by washing. 2. Upon closure of the backwater system for unbleached pulp, a small portion of resin is always dispersed. The resin content of the unbleached pulp increases with increasing backwater closure. 3 During the bleaching stage of these pulps, the resin is transferred in such a form that the main part of the resin is dispersed. The resin is modified during bleaching so that it does not precipitate in the reinforced closure. 4 The amount of undispersible resin in peroxide-bleached bleached chemmechanical pulp is equal to the amount of pulp.
Only 0.05-0.15%. These discoveries suggest that when the pulp is washed before and after bleaching and the backwater is moved countercurrently to the pulp, bleached chemi-mechanical pulp with very low resin content can be produced with low water consumption. enable. An embodiment of the invention is shown in FIG. Of course, the present invention is not limited to this specific example. Feed the chips to refiner stage 1. Therefore, there is no need to process the chips, and steam treatment and/or
Alternatively, it may be impregnated with chemicals. After refiner 1 the pulp is sent to washing stage 2. This may be a washing filter, but dehydration or washing squeezing is preferred. The pulp suspension is diluted with backwater from the bleaching stage before the washing stage and if necessary with backwater from washing stage 2. The unbleached pulp after washing stage 2 is fed with bleaching agent and dilution water coming from washing stage 4 and sent to bleaching tower 3. After bleaching, dilute with back water from wash stage 4 and wash in wash stage 4. The backwater from washing and dewatering stage 5 is utilized as a displacement liquid. The pulp is dehydrated in dehydration stage 5 before drying 6,
This stage 5 is preferably dehydration or washing and pressing. Backwater passes through cleaning stage 2 and leaves the system. The cleaning liquid is supplied in connection with the cleaning stage 5. The results can be explained as follows. Refine the CTMP chip in step 1.
The pulp density after refiner is 30%. The pulp is dehydrated in dehydration press 2 to a pulp density of 48%. The pulp is then bleached at a pulp concentration of 12%, washed with washing filter 4 and finally washed with 48 ml before drying 6.
% pulp concentration by dehydration pressing 5. Using the automation model and the experimental results obtained, the resin budget for the system is calculated at different degrees of closure. The following relationship was obtained between the cleaning effectiveness of the resins dissolved or dispersed in the bleaching stage and the backup water exiting the system and the resin content in the bleached pulp. The undispersed resin content in the pulp after the bleaching step is assumed to be 0.13%. Assume that the resin content in the pulp after refining is 0.9%.
【表】
パルプが向流で洗浄されるなら低樹脂含量を有
するさらしケミメカニカルパルプを製造する事は
厳重な閉鎖によつては可能である事が計算により
示される。
ケミメカニカルパルプ又はそれと同様な物（90
％以上の歩留りのパルプ）の過酸化物漂白は標準
的条件下では多大な化学薬品の残留物を生じ、前
記残留物は漂白条件を厳密にする事による単純な
方法では利用し得ず、漂白後の化学薬品の樹脂溶
液が未さらしパルプに戻される時、多少とも高レ
ベルで利用し得る。その様な戻し作業を行うに
は、通常用いられる装置よりもより優れた装置と
より優れたウオーター・システムの制御を必要と
する。その様は戻し実験が行なわれ、比較的良い
結果を得た。しかし、おそらく希釈現象及び他の
妨害効果が比較的非合理的方法で処理過程に影響
するため、有効度が低い事が立証された。
厳密に選択された条件によりこれらの化学薬品
の残留物を用いて約100％の漂白有効性が得られ
得る事が、驚くべき事に知見された。所定の条件
とは、化学薬品が微量の希釈のみを伴つて戻さ
れ、漂白前のリフアイニング段階からのバツクウ
オーターが小さいレベルのその様な希釈を提供し
得る事である。これはその代わりに厳密に均衡が
保たれたバツクウオーター・システムを必要と
し、そのシステムに於いて、リフアイナー段階の
バツクウオーターと漂白段階のバツクウオーター
は厳密に分離される。
バツクウオーターが混合する危険性がなく、又
同時に漂白プラントからの化学薬品の残留物を最
大限に戻すための所定条件を提供する二つの処理
段階の分離の最良の方法は、漂白プラントの直前
に圧搾装置を配備する事である事が立証された。
漂白プラントのウオーター・システムに、前段階
からの少量の液のみを提供し、漂白プラント後の
限定された洗浄水量に於いては少量の漂白プラン
トのバツクウオーターのみが流出されなければな
らない。流出量が減少するにつれ、利用される化
学薬品の残留物の割合が増加する。システム内へ
の減退された希釈により、化学薬品の残留物の漂
白反応に於ける妨害の危険性は減少する。
前述にかんがみて、漂白処理は次の様に考案さ
れ得る。
漂白プラントの直前に、パルプは少なくとも20
％の乾燥分含有量に圧搾し、その場合洗浄に連結
しても良い。より大きな乾燥分含有量が好まし
く、通常は最低でも30％、最高で約50％が達成さ
れるべきである。次に、漂白からの化学薬品残留
物を有する僅かに希釈された漂白プラントツクウ
オーターで、雰囲気により約５％〜15％の間で変
化し得る通常の漂白用パルプ濃度にまで希釈す
る。その後、新しい過酸化物溶液及び必要な補助
化学薬品を公知の方法でパルプに混合し、パルプ
をシステム内の温度に適合する時間内で漂白す
る。通常の時間は0.1〜４時間で、通常の温度は
45〜85℃である。漂白開始時にはPHは高く、８〜
９まで次第に減少する。非アルカリ性不正着色が
生ずるため、漂白は常に化学薬品が完全に消費さ
れる前に終了する。高白色度を得るために、化学
薬品の残留量は通常むしろ多量でなくてはならな
い。その後、残留溶液が回収される例えば洗浄フ
イルターの様な高い洗浄有効性を持つ洗浄段階に
パルプを送る。残留溶液を希釈しないために、少
量の洗浄液すなわち低希釈フアクターで洗浄す
る。次に、この溶液を漂白プラントの直前に希釈
のために戻す。
方法は、次のような実験研究及び準工業的パイ
ロツトプラントから説明される。
直接戻される過酸化物漂白の残留溶液の有効性
は実験研究から説明される。その実験に於いて、
サーモメカニカルパルプ及びCTMPは最初に新
しい化学薬品で漂白され、その後残留溶液は過酸
化物で滴定され、先行の漂白実験と同じ総投入量
で新しい過酸化物、水酸化ナトリウム、ケイ酸ナ
トリウム、硫酸マグネシウムにより強化され、そ
の後パルプを新しい漂白溶液で同様に漂白する。
これをさらに一回繰り返して、後の実験からの残
留溶液を再循環された残留溶液中の有機物質の割
合が増加する時、漂白が悪変しないように制御す
るため戻す。下の表で明らかな様に、様々な変形
例は実質的に同じ結果を有す。この結果は、漂白
が12％のパルプ濃度で且つ残留溶液中の高い過酸
化物含量で行われる時に得られた。
酸留溶液をさらに希釈して戻し且つ漂白をいく
らかより低いパルプ濃度で行う後の類似の実験に
於いて、投入された過酸化物に対して、僅かに低
下した白色度が得られた（最高投入時よりも約２
単位低い）。
新しい漂白剤による通常の過酸化物漂白。[Table] Calculations show that it is possible with tight closure to produce bleached chemical mechanical pulp with low resin content if the pulp is washed in countercurrent. Chemical mechanical pulp or similar material (90
Peroxide bleaching of pulps with a yield of more than When the later chemical resin solution is returned to the unbleached pulp, it can be utilized at more or less high levels. Performing such a return operation requires better equipment and better control of the water system than is normally used. In this case, a reversal experiment was conducted and relatively good results were obtained. However, it has proven to be less effective, probably because dilution phenomena and other interfering effects affect the process in a relatively irrational manner. It has surprisingly been found that with carefully selected conditions bleaching efficiencies of approximately 100% can be obtained using residues of these chemicals. The predetermined conditions are that the chemicals are returned with only a small amount of dilution and that the back water from the refining step prior to bleaching can provide a small level of such dilution. This instead requires a strictly balanced backwater system in which the backwater of the refiner stage and the backwater of the bleaching stage are strictly separated. The best method of separation of the two processing stages, without the risk of mixing of the backwaters and at the same time providing conditions for the maximum return of chemical residues from the bleaching plant, is to It was proven that the solution was to deploy a squeezing device.
The bleach plant water system is provided with only a small amount of liquid from the previous stage, and in the limited amount of wash water after the bleach plant, only a small amount of bleach plant backwater must be drained. As the effluent volume decreases, the percentage of chemical residue utilized increases. Due to the reduced dilution into the system, the risk of interference of chemical residues in the bleaching reaction is reduced. In view of the foregoing, the bleaching process may be devised as follows. Immediately before the bleaching plant, the pulp is at least 20
% dry matter content, in which case it may be combined with washing. Higher dry matter contents are preferred and usually a minimum of 30% and a maximum of about 50% should be achieved. It is then diluted with slightly diluted bleaching plant water with chemical residue from bleaching to a normal bleaching pulp concentration which can vary between about 5% and 15% depending on the atmosphere. Fresh peroxide solution and the necessary auxiliary chemicals are then mixed into the pulp in a known manner and the pulp is bleached for a time compatible with the temperature in the system. The normal time is 0.1-4 hours, and the normal temperature is
The temperature is 45-85℃. At the start of bleaching, the pH is high, 8~
It gradually decreases to 9. Bleaching is always terminated before the chemicals are completely consumed, as non-alkaline color discoloration occurs. In order to obtain high brightness, the residual amount of chemicals usually has to be rather large. Thereafter, the pulp is sent to a washing stage with high cleaning effectiveness, such as a washing filter, where the residual solution is recovered. Wash with a small amount of wash solution, ie, a low dilution factor, to avoid diluting the residual solution. This solution is then returned for dilution just before the bleaching plant. The method is illustrated from experimental studies and semi-industrial pilot plants as follows. The effectiveness of directly reconstituted peroxide bleach residual solutions is illustrated from experimental studies. In that experiment,
The thermomechanical pulp and CTMP were first bleached with fresh chemicals, then the residual solution was titrated with peroxide, and fresh peroxide, sodium hydroxide, sodium silicate, and sulfuric acid were added at the same total inputs as in the previous bleaching experiment. After being strengthened with magnesium, the pulp is similarly bleached with fresh bleaching solution.
This is repeated one more time and the residual solution from a later experiment is returned to control the bleaching from deteriorating as the proportion of organic material in the recycled residual solution increases. As can be seen in the table below, the various variants have substantially the same results. This result was obtained when bleaching was carried out at a pulp concentration of 12% and a high peroxide content in the residual solution. In similar experiments after further dilution of the acid distillate solution and bleaching at a somewhat lower pulp concentration, a slightly reduced brightness was obtained for the peroxide charge (up to Approximately 2 more than at the time of injection
unit low). Regular peroxide bleaching with fresh bleach.
【表】
物
[Table] Things
Claims (1)
約90％を越える歩留りで、木材原料を亜硫酸溶液
に含浸させ、予熱し、次いで機械的離解し、その
後に該離解材料をアルカリ条件下で過酸化物漂白
することによつて製造する方法であり、前記方法
はパルプ１トンあたり多くとも15m3の廃水量に相
当する閉鎖システムで行なわれ、前記方法が少な
くとも１つの離解段階(1)、離解後にパルプが圧搾
され洗浄される少なくとも１つの洗浄段階(2)、少
なくとも１つの漂白段階(3)及び少なくとも１つの
漂白パルプの洗浄段階(4)を含み、 ―漂白後の洗浄段階(4)に洗浄液が供給され、 ―漂白後の洗浄段階(4)からのバツクウオーターの
一部は洗浄段階(2)後のパルプの希釈に使用し、
一部は離解段階(1)からのパルプの希釈及び洗浄
に使用し、 ―離解段階(1)からのバツクウオーターと漂白段階
(3)からのバツクウオーターとが相互に切り離さ
れて維持され、離解段階(1)からのバツクウオー
ターが漂白段階のバツクウオーターシステムに
移行しないようにし、 ―工程から除去すべきバツクウオーターを離解段
階(1)後に配置された洗浄段階(2)に於いて排出
し、 ―工程の洗浄有効度は少なくとも70％であること
を特徴とする前記方法。 ２ 離解段階はリフアイニング段階であることを
特徴とする特許請求の範囲第１項に記載の方法。 ３ 離解段階からのバツクウオーターと漂白段階
からのバツクウオーターは、好ましくは洗浄圧搾
の形で前記２つの段階の間には中間洗浄段階を配
備することにより、相互に切り離して維持される
ことを特徴とする特許請求の範囲第１項に記載の
方法。 ４ 漂白段階前の洗浄段階と漂白段階後の洗浄段
階は連続して配置され、洗浄水はパルプ流液に対
して必然的に向流で流すことを特徴とする特許請
求の範囲第３項に記載の方法。 ５ 漂白は60℃以上、好ましくは70〜85℃の温度
で行なわれることを特徴とする特許請求の範囲第
１項に記載の方法。 ６ 機械的離解後のパルプは25〜50％、好ましく
は30〜45％のパルプ濃度に圧搾され、その後パル
プは漂白段階からの残留漂白液によつて実質的に
希釈されることを特徴とする特許請求の範囲第１
項乃至第５項のいずれかに記載の方法。 ７ 漂白段階からの過剰漂白液は漂白段階後に配
置された洗浄段階で濃縮された形で回収され、洗
浄段階に於ける希釈フアクターはパルプ１トン当
たり０〜２m3、好ましくはパルプ１トン当たり
0.5〜1.5m3に限定されることを特徴とする特許請
求の範囲第６項に記載の方法。[Scope of Claims] 1 A substantially resin-free cellulose pulp with a yield of more than about 90% is impregnated with a sulfurous acid solution, preheated, and then mechanically disintegrated, after which the disintegrated material is alkalised. A process for producing by peroxide bleaching under conditions, said process being carried out in a closed system corresponding to a waste water volume of at most 15 m 3 per ton of pulp, said process comprising at least one disintegration stage ( 1), at least one washing stage (2) in which the pulp is pressed and washed after disintegration, at least one bleaching stage (3) and at least one washing stage of the bleached pulp (4), - a post-bleaching washing stage; washing liquid is supplied to (4), - a portion of the back water from the post-bleaching washing stage (4) is used to dilute the pulp after the washing stage (2);
A portion is used for diluting and washing the pulp from the disintegration stage (1); - Backwater from the disintegration stage (1) and the bleaching stage;
(3) are kept separate from each other to prevent backwater from the disintegration stage (1) from passing into the bleaching stage backwater system; (1) discharging in a subsequent cleaning step (2), wherein the cleaning effectiveness of the step is at least 70%. 2. The method according to claim 1, wherein the disaggregation step is a refining step. 3. characterized in that the backwater from the disintegrating stage and the backwater from the bleaching stage are kept separate from each other by arranging an intermediate washing stage between said two stages, preferably in the form of a washing press; A method as claimed in claim 1. 4. Claim 3, characterized in that the washing stage before the bleaching stage and the washing stage after the bleaching stage are arranged in series, and the washing water necessarily flows countercurrently to the pulp flow liquid. Method described. 5. Process according to claim 1, characterized in that the bleaching is carried out at a temperature of 60°C or above, preferably 70-85°C. 6. The pulp after mechanical disintegration is pressed to a pulp consistency of 25-50%, preferably 30-45%, after which the pulp is substantially diluted by the residual bleaching liquor from the bleaching stage. Claim 1
6. The method according to any one of items 5 to 5. 7. The excess bleaching liquor from the bleaching stage is recovered in concentrated form in a washing stage arranged after the bleaching stage, the dilution factor in the washing stage being between 0 and 2 m 3 per tonne of pulp, preferably per tonne of pulp.
7. A method according to claim 6, characterized in that it is limited to 0.5 to 1.5 m <3> .
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8002728A SE445051B (en) | 1980-04-10 | 1980-04-10 | SET FOR MANUFACTURING MECHANICAL, MAINLY HEART-FREE CELLULOSAMASSA |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56159384A JPS56159384A (en) | 1981-12-08 |
| JPH0219236B2 true JPH0219236B2 (en) | 1990-05-01 |
Family
ID=20340719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5377081A Granted JPS56159384A (en) | 1980-04-10 | 1981-04-09 | Production of mechanical cellulose pulp |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS56159384A (en) |
| AU (2) | AU6901281A (en) |
| CA (1) | CA1174013A (en) |
| DE (1) | DE3114427A1 (en) |
| FI (1) | FI73016C (en) |
| FR (1) | FR2480321A1 (en) |
| IT (1) | IT1209859B (en) |
| NL (1) | NL187865C (en) |
| NO (1) | NO159107C (en) |
| SE (1) | SE445051B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105064110A (en) * | 2015-07-29 | 2015-11-18 | 华南理工大学 | Cotton linter pulping device and pulping method thereof |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2567930B1 (en) * | 1984-07-17 | 1986-08-29 | Centre Tech Ind Papier | PROCESS AND INSTALLATION FOR RECYCLING OF OLD PRINTED PAPERS |
| SE8501246L (en) * | 1985-03-13 | 1986-09-14 | Eka Ab | SET TO MANUFACTURE IN BLEACH, CHEMICAL MECHANICAL AND SEMI-CHEMICAL FIBER MASS USING ONE-STEP IMAGRATION |
| CA1294396C (en) * | 1986-05-30 | 1992-01-21 | Richard Berry | Process for decreasing the charge of chemical required in a bleaching extraction stage |
| FI115978B (en) * | 2000-11-16 | 2005-08-31 | Ciba Sc Holding Ag | Process for the recovery of non-fibrous substances from wood material |
| CN105019286B (en) * | 2015-07-29 | 2017-01-25 | 华南理工大学 | Device and method for making refined cottons through performing high-concentration hydrogen peroxide bleaching on cotton linters |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE420329C (en) * | 1978-02-16 | 1984-10-15 | Mo Och Domsjoe Ab | PROCEDURE FOR THE PREPARATION OF GRINDING PAPER |
| CA1151363A (en) * | 1979-04-17 | 1983-08-09 | Henri Lemoyne | Process for the delignification of unbleached chemical pulp |
| SE443383C (en) * | 1981-01-14 | 1987-11-16 | Mo Och Domsjoe Ab | PROCEDURE FOR WASHING CELLULOSAMASSA |
| FR2522030A1 (en) * | 1982-02-19 | 1983-08-26 | Scherb Metenett Papeteries | PROCESS FOR SELECTIVELY WHITENING PAPER PULP AND PAPER OBTAINED BY CARRYING OUT SAID METHOD |
-
1980
- 1980-04-10 SE SE8002728A patent/SE445051B/en not_active IP Right Cessation
-
1981
- 1981-04-01 AU AU69012/81A patent/AU6901281A/en not_active Abandoned
- 1981-04-06 FR FR8106834A patent/FR2480321A1/en active Granted
- 1981-04-07 IT IT8148224A patent/IT1209859B/en active
- 1981-04-08 NL NLAANVRAGE8101748,A patent/NL187865C/en not_active IP Right Cessation
- 1981-04-09 FI FI811096A patent/FI73016C/en not_active IP Right Cessation
- 1981-04-09 CA CA000375146A patent/CA1174013A/en not_active Expired
- 1981-04-09 NO NO811225A patent/NO159107C/en unknown
- 1981-04-09 DE DE19813114427 patent/DE3114427A1/en active Granted
- 1981-04-09 JP JP5377081A patent/JPS56159384A/en active Granted
-
1984
- 1984-01-09 AU AU23169/84A patent/AU568112B2/en not_active Ceased
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105064110A (en) * | 2015-07-29 | 2015-11-18 | 华南理工大学 | Cotton linter pulping device and pulping method thereof |
| CN105064110B (en) * | 2015-07-29 | 2017-04-12 | 华南理工大学 | Cotton linter pulping device and pulping method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| FI73016C (en) | 1987-08-10 |
| CA1174013A (en) | 1984-09-11 |
| SE8002728L (en) | 1981-10-11 |
| NO159107B (en) | 1988-08-22 |
| NL187865B (en) | 1991-09-02 |
| AU6901281A (en) | 1981-10-29 |
| FI811096L (en) | 1981-10-11 |
| NL8101748A (en) | 1981-11-02 |
| NO159107C (en) | 1988-11-30 |
| AU568112B2 (en) | 1987-12-17 |
| FR2480321A1 (en) | 1981-10-16 |
| AU2316984A (en) | 1984-05-10 |
| SE445051B (en) | 1986-05-26 |
| IT1209859B (en) | 1989-08-30 |
| NL187865C (en) | 1992-02-03 |
| NO811225L (en) | 1981-10-12 |
| IT8148224A0 (en) | 1981-04-07 |
| JPS56159384A (en) | 1981-12-08 |
| FI73016B (en) | 1987-04-30 |
| DE3114427A1 (en) | 1982-01-14 |
| DE3114427C2 (en) | 1987-12-17 |
| FR2480321B1 (en) | 1984-09-14 |
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