EP0060277B1 - Process to produce pulps - Google Patents
Process to produce pulps Download PDFInfo
- Publication number
- EP0060277B1 EP0060277B1 EP81902585A EP81902585A EP0060277B1 EP 0060277 B1 EP0060277 B1 EP 0060277B1 EP 81902585 A EP81902585 A EP 81902585A EP 81902585 A EP81902585 A EP 81902585A EP 0060277 B1 EP0060277 B1 EP 0060277B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pulp
- stage
- fibrous material
- solution
- treated
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 36
- 230000008569 process Effects 0.000 title claims abstract description 35
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 23
- 239000002657 fibrous material Substances 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims abstract description 17
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000001301 oxygen Substances 0.000 claims abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 7
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 7
- 239000000243 solution Substances 0.000 claims abstract description 7
- 238000010411 cooking Methods 0.000 claims abstract description 6
- 239000010902 straw Substances 0.000 claims abstract description 6
- 239000000725 suspension Substances 0.000 claims abstract description 6
- 235000013311 vegetables Nutrition 0.000 claims abstract description 6
- 241000609240 Ambelania acida Species 0.000 claims abstract description 5
- 239000010905 bagasse Substances 0.000 claims abstract description 5
- 239000012670 alkaline solution Substances 0.000 claims abstract description 3
- 239000011121 hardwood Substances 0.000 claims abstract description 3
- 238000003756 stirring Methods 0.000 claims abstract description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 18
- 239000000126 substance Substances 0.000 claims description 15
- 238000004061 bleaching Methods 0.000 claims description 14
- 238000011282 treatment Methods 0.000 claims description 9
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 5
- 229910001882 dioxygen Inorganic materials 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000003245 coal Substances 0.000 claims description 3
- 238000005470 impregnation Methods 0.000 claims description 3
- 239000002023 wood Substances 0.000 abstract description 5
- 229920002678 cellulose Polymers 0.000 abstract description 2
- 239000001913 cellulose Substances 0.000 abstract description 2
- PFUVRDFDKPNGAV-UHFFFAOYSA-N sodium peroxide Chemical compound [Na+].[Na+].[O-][O-] PFUVRDFDKPNGAV-UHFFFAOYSA-N 0.000 abstract 1
- 241000196324 Embryophyta Species 0.000 description 9
- 239000002994 raw material Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000376 reactant Substances 0.000 description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 235000011121 sodium hydroxide Nutrition 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 229920001131 Pulp (paper) Polymers 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000005864 Sulphur Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- 239000004155 Chlorine dioxide Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 241000209140 Triticum Species 0.000 description 2
- 235000021307 Triticum Nutrition 0.000 description 2
- 239000003513 alkali Chemical class 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000009993 causticizing Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 235000019398 chlorine dioxide Nutrition 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 159000000011 group IA salts Chemical class 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 229910021653 sulphate ion Inorganic materials 0.000 description 2
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 1
- 241000736542 Awaous banana Species 0.000 description 1
- 244000025254 Cannabis sativa Species 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 244000060011 Cocos nucifera Species 0.000 description 1
- 235000013162 Cocos nucifera Nutrition 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 244000068988 Glycine max Species 0.000 description 1
- 235000010469 Glycine max Nutrition 0.000 description 1
- 244000299507 Gossypium hirsutum Species 0.000 description 1
- 240000000797 Hibiscus cannabinus Species 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 240000006240 Linum usitatissimum Species 0.000 description 1
- 235000004431 Linum usitatissimum Nutrition 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 244000273256 Phragmites communis Species 0.000 description 1
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000002154 agricultural waste Substances 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001804 chlorine Chemical class 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000005213 imbibition Methods 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000000050 nutritive effect Effects 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 238000004076 pulp bleaching Methods 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000003911 water pollution Methods 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/04—Regeneration of pulp liquors or effluent waste waters of alkali lye
-
- 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
- D21C3/026—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes in presence of O2, e.g. air
-
- 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
- D21C9/1073—Bleaching ; Apparatus therefor with O3
Definitions
- This invention refers to a process to produce pulps from vegetable, lignocellulose-containing fibrous material, e.g. coniferous wood, straw and bagasse.
- the mentioned drawbacks involve also high energy consumption due to the plants for impregnation of the raw material with cooking chemicals, for pulp bleaching, for recovery of chemicals and for environment protection.
- the main object of the invention is to provide a process for production of pulps wherein the handling of the chemicals is simplified so that the aforestated drawbacks are avoided.
- a second object of the invention is by the simplified handling of chemicals to obtain lower investment costs which results in that minor plants also become profitable, which permits the installation of plants nearer the raw material sources with consequent reduction of transport costs, which also involves a generally widened range of raw or starting materials.
- a third object of the invention is to render possible in this connection a widened utilization of non-traditional raw materials for production of pulps such as green chips, i.e. twigs, branches, bushes and shrubs and low-grade timber especially from coniferous wood as result from various thinning and cleaning operations, furthermore agricultural wastes like wheat, rice straw and bagasse, but also e.g.
- banana stems, soybeans and coconut shells furthermore also from other annual vegetables cultivated for their fibre content more than with regard to their nutritive value, such as cotton, flax, kenaf, but also wild annual vegetables such as certain kinds of grass and reeds, and finally also wastes from tradiational woodworking industry in the shape of sawmill waste and especially waste from tropical kinds of wood possessing very high density and therefore difficult to treat with conventional processes of pulp production, and waste from traditional pulp industry in the shape of knot catcher rejects and some kind of fibre sludge.
- other annual vegetables cultivated for their fibre content more than with regard to their nutritive value such as cotton, flax, kenaf, but also wild annual vegetables such as certain kinds of grass and reeds
- the fibrous material is subjected to a sequence of treatment stages, of which in stage 1 the fibrous material is impregnated with a solution of sodium hydroxide in which the material is soaked during a time of from 15 to 45 minutes at a temperature of between 50° and 110°C, and simultaneously partially disintegrated by mechanical working, that in stage 2 the excess of alkaline solution is squeezed out from the fibrous material until the dry content of the treated material amounts to 20-55% and its content of sodium hydroxide amounts to at least 15 kgs per ton of treated material calculated as dry substance (BD ton of treated material), that in stage 3 the fibrous material is subjected to additional disintegration under supply of a solution of sodium carbonate .
- stage 1 the fibrous material is impregnated with a solution of sodium hydroxide in which the material is soaked during a time of from 15 to 45 minutes at a temperature of between 50° and 110°C, and simultaneously partially disintegrated by mechanical working, that in stage 2 the excess of alkaline solution is squeezed out from the fibr
- stage 4 the treated material suspension is subjected in a pressurized reactor to a cooking process at a temperature of at least 110°C during 1-4 hours and under stirring and supply of oxygen, whereafter the cooked pulp is washed.
- the fibrous material Prior to the impregnation with sodium hydroxide, the fibrous material can be washed and simultaneously pre-disintegrated.
- the finally treated pulp can be bleached in known manner by means of-ozone, the ozone (0 3 ) being produced from oxygen gas (0 2 ) in ozonisers, and after the bleaching the oxygen gas is purified from remainders of ozone by being passed through a coal bed in the presence of water and thereafter returned into the process.
- sodium carbonate is used as a reactant.
- the reactivity of the mentioned salt is known to be low towards lignine but also towards the cellulosic components and the cellulose and in any case inferior to the reactivity of the correspondent hydrate. Therefore the carbonate is activated, in stage 3 after a first delignification has been accomplished by means of sodium hydrate in stage 1, where chips imbibition takes place, in quantities corresponding to the necessary ones to make up the loss of process reactants.
- the quantity varies, according to raw materials and final products, between 15 and 30 kg of hydrate per BDT (bone dry ton) of processed fibrous material.
- stage 3 For the activation 0 2 also and possibly other oxidative agents (peroxides) are used in stage 3 where working pressure, temperature and amount of O2 are varied within very wide limits (10-20 Bar, 110 ⁇ 150°C and 6-14% of 0 2 ) according to raw material and desired final products.
- the process according to the invention is therefore characterized by the use of carbonate as alkaline salt directly in the process of delignification (stage 3).
- Very good delignification (kappa no between 15 and 8) has been obtained with the aforedescribed process simultaneously with viscosity levels high enough after the subsequent bleaching process to ensure good characteristics of resistance of the paper puIp together with a brightness of about 50% Scan, impossible to be obtained by any known alkaline process.
- Characteristic for the process according to the invention is also that it yields pulps with low extractive content and with high cleanliness in spite of utilization of low quality raw material containing bark, for example. This is due to the fact that oxygen gas in alkaline medium reacts specifically with bark and fibre bundles which are difficult to become delignified by usual processes.
- pulps produced according to the invention are highly bleachable by ozone which affords a number of advantages.
- Ozone bleaching is carried out in a single stage at atmospheric pressure. Investment and energy costs of the ozone bleaching are lower than for other comparable processes.
- the production costs for ozone and chlorine dioxide are on the same level with today's technology, the energy consumption is 10 kWh per kg ozone, provided that ozonisers are fed with oxygen, in comparison to 12-14 kWh per kg of chlorine dioxide starting from sodium chlorate.
- the effluent from the ozone bleaching stage can be conveyed to black liquor evaporation and combustion, for which reason environmental pollution is reduced to a minimum.
- the process according to the invention is characterized also by the possibility of utilizing O2 (moist and not pure) resulting from the ozone bleaching treatment.
- Industrial ozonisers when fed with oxygen yield a gas mixture where the ozone content is 2.5-2.7 vol %, the rest being oxygen.
- oxygen may be recycled to stage 3.
- the gas mixture coming from the bleaching stage is here passed through an ozone purifier in the shape of a coal bed in the presence of water in order to prevent carbohydrate degradation which is particularly severe at the used high reactor temperature even when traces only of ozone are present.
- Black liquors contain those inorganic chemicals which have been used for the delignification, chemicals to a small extent as free reactants and for the most part in combination with salts of organic acids, alkali lignine and other compounds of sometimes very complex structure and forming non-cullulosic wood components.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
Abstract
Description
- This invention refers to a process to produce pulps from vegetable, lignocellulose-containing fibrous material, e.g. coniferous wood, straw and bagasse.
- Traditional processes to produce pulps, (see for example US-A-3769152, US-A-4045279 and US-A-3 691 008) and particularly the sulphate process which is used to produce almost the total chemical pulp on the world market, have considerable drawbacks. Thus, there are required in order to bring about in the cooking system an even distribution of reaction agents in the starting or raw material and thereby good delignification, plants with pressurized reaction devices of big volume and circulation of remarkable quantities of liquids heated by heat exchangers. Such plants are extremely expensive. The obtained pulp is difficult to bleach, for which reason very complex and highly expensive bleaching plants become necessary for treatment of the pulp. Furthermore, the cooking and bleaching process causes pollution of air and water which is unacceptable. Therefore, internal treatment plants such as combustion and chemical recovery installations, and external treatment plants such as water purifying basins, are necessary to bring the effluents to acceptable level, which require high initial investment costs, which in turn implies demand for large production units. Air and water pollution are mainly due to the use of chemical reactants which contain sulphur and chlorine and chlorine derivatives, the latter ones in large amounts as consequence of the aforesaid low bleachability of the pulps. The presence of sulphur brings about i.a. the characteristic evil smell from plants operating with the sulphate process.
- The mentioned drawbacks involve also high energy consumption due to the plants for impregnation of the raw material with cooking chemicals, for pulp bleaching, for recovery of chemicals and for environment protection.
- The main object of the invention is to provide a process for production of pulps wherein the handling of the chemicals is simplified so that the aforestated drawbacks are avoided. A second object of the invention is by the simplified handling of chemicals to obtain lower investment costs which results in that minor plants also become profitable, which permits the installation of plants nearer the raw material sources with consequent reduction of transport costs, which also involves a generally widened range of raw or starting materials.
- A third object of the invention is to render possible in this connection a widened utilization of non-traditional raw materials for production of pulps such as green chips, i.e. twigs, branches, bushes and shrubs and low-grade timber especially from coniferous wood as result from various thinning and cleaning operations, furthermore agricultural wastes like wheat, rice straw and bagasse, but also e.g. banana stems, soybeans and coconut shells, furthermore also from other annual vegetables cultivated for their fibre content more than with regard to their nutritive value, such as cotton, flax, kenaf, but also wild annual vegetables such as certain kinds of grass and reeds, and finally also wastes from tradiational woodworking industry in the shape of sawmill waste and especially waste from tropical kinds of wood possessing very high density and therefore difficult to treat with conventional processes of pulp production, and waste from traditional pulp industry in the shape of knot catcher rejects and some kind of fibre sludge.
- These and other objects of the invention are obtained by providing a process to produce pulps from vegetable, lignocellulose-containing fibrous materials such as coniferous and hard-wood, straw, bagasse and the like, characterized in that. the fibrous material is subjected to a sequence of treatment stages, of which in stage 1 the fibrous material is impregnated with a solution of sodium hydroxide in which the material is soaked during a time of from 15 to 45 minutes at a temperature of between 50° and 110°C, and simultaneously partially disintegrated by mechanical working, that in stage 2 the excess of alkaline solution is squeezed out from the fibrous material until the dry content of the treated material amounts to 20-55% and its content of sodium hydroxide amounts to at least 15 kgs per ton of treated material calculated as dry substance (BD ton of treated material), that in stage 3 the fibrous material is subjected to additional disintegration under supply of a solution of sodium carbonate . so that a pumpable treated material suspension having a sodium carbonate content of 150-400 kg per BD ton of treated material is obtained, that in stage 4 the treated material suspension is subjected in a pressurized reactor to a cooking process at a temperature of at least 110°C during 1-4 hours and under stirring and supply of oxygen, whereafter the cooked pulp is washed.
- Prior to the impregnation with sodium hydroxide, the fibrous material can be washed and simultaneously pre-disintegrated. The finally treated pulp can be bleached in known manner by means of-ozone, the ozone (03) being produced from oxygen gas (02) in ozonisers, and after the bleaching the oxygen gas is purified from remainders of ozone by being passed through a coal bed in the presence of water and thereafter returned into the process.
- The use according to the invention of other chemical reactants than sulphur and its compounds and compositions with sodium in an alkaline surrounding, molecular chlorine and, in addition, a significant reduction of the use of chloro-derivatives result in a reduction of environment pollution. Thus, i.a. the problem of evil smell can practically be eliminated by the process of the present invention. The use of the proposed chemical reactants allows simplification of the plants for recovery of chemicals and heat and assures also the production of chemical pulps which are easily bleachable, making bleaching plants less complex and less capital-intensive. According to the invention, it is possible to produce, in addition to chemical pulps, also pulps of the so-called chemi-mechanical and semi- chemical types.
- In accordance with the invention sodium carbonate is used as a reactant. The reactivity of the mentioned salt is known to be low towards lignine but also towards the cellulosic components and the cellulose and in any case inferior to the reactivity of the correspondent hydrate. Therefore the carbonate is activated, in stage 3 after a first delignification has been accomplished by means of sodium hydrate in stage 1, where chips imbibition takes place, in quantities corresponding to the necessary ones to make up the loss of process reactants.
- The quantity varies, according to raw materials and final products, between 15 and 30 kg of hydrate per BDT (bone dry ton) of processed fibrous material.
- For the activation 02 also and possibly other oxidative agents (peroxides) are used in stage 3 where working pressure, temperature and amount of O2 are varied within very wide limits (10-20 Bar, 110―150°C and 6-14% of 02) according to raw material and desired final products. The process according to the invention is therefore characterized by the use of carbonate as alkaline salt directly in the process of delignification (stage 3).
- Very good delignification (kappa no between 15 and 8) has been obtained with the aforedescribed process simultaneously with viscosity levels high enough after the subsequent bleaching process to ensure good characteristics of resistance of the paper puIp together with a brightness of about 50% Scan, impossible to be obtained by any known alkaline process.
- Characteristic for the process according to the invention is also that it yields pulps with low extractive content and with high cleanliness in spite of utilization of low quality raw material containing bark, for example. This is due to the fact that oxygen gas in alkaline medium reacts specifically with bark and fibre bundles which are difficult to become delignified by usual processes.
- These properties of the pulps and particularly the high brightness permit very simplified bleaching treatments in comparison with usual processes. Particularly, chlorine treatment of the pulp is not required.
-
- As is apparent from this table, pulps produced according to the invention are highly bleachable by ozone which affords a number of advantages. Ozone bleaching is carried out in a single stage at atmospheric pressure. Investment and energy costs of the ozone bleaching are lower than for other comparable processes. The production costs for ozone and chlorine dioxide are on the same level with today's technology, the energy consumption is 10 kWh per kg ozone, provided that ozonisers are fed with oxygen, in comparison to 12-14 kWh per kg of chlorine dioxide starting from sodium chlorate. The effluent from the ozone bleaching stage can be conveyed to black liquor evaporation and combustion, for which reason environmental pollution is reduced to a minimum.
- The process according to the invention is characterized also by the possibility of utilizing O2 (moist and not pure) resulting from the ozone bleaching treatment. Industrial ozonisers when fed with oxygen yield a gas mixture where the ozone content is 2.5-2.7 vol %, the rest being oxygen. After exhaustion by reaction of ozone in the bleaching process oxygen may be recycled to stage 3. The gas mixture coming from the bleaching stage is here passed through an ozone purifier in the shape of a coal bed in the presence of water in order to prevent carbohydrate degradation which is particularly severe at the used high reactor temperature even when traces only of ozone are present.
- Every process for recovery of chemicals and heat involved necessarily combustion, mostly after concentration by evaporation, to a dry content of 50-60% of black liquors collected from the pulp washing during and/or after the delignification process. Black liquors contain those inorganic chemicals which have been used for the delignification, chemicals to a small extent as free reactants and for the most part in combination with salts of organic acids, alkali lignine and other compounds of sometimes very complex structure and forming non-cullulosic wood components.
- Combustion of black liquors liberates carbon dioxide (C02) and for this reason the alkaline salts are recovered as carbonates in a sulphur-free process. Conventionally, the carbonate is turned to hydrate in order to restore the reactivity and delignifying capacity of the alkali, which procedure is carried out in so-called causticizing plants which involve high investment costs, high energy consumption and cause considerable injury to the environment. The direct utilization of carbonate in the delignification process according to the invention thus eliminates the causticizing step and the disadvantageous effects thereof.
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT81902585T ATE18782T1 (en) | 1980-09-22 | 1981-09-21 | PROCESS FOR MAKING PAPER PULP. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT24818 | 1980-09-22 | ||
IT8024818A IT1209352B (en) | 1980-09-22 | 1980-09-22 | PROCESS FOR THE PRODUCTION OF CHEMICAL CELLULOSE AND / OR PAPER PASTES, AS WELL AS THE PLANT AND ITS COMPONENTS FOR THE IMPLEMENTATION OF THE INDICATED PROCESS |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0060277A1 EP0060277A1 (en) | 1982-09-22 |
EP0060277B1 true EP0060277B1 (en) | 1986-03-26 |
Family
ID=11214834
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP81902585A Expired EP0060277B1 (en) | 1980-09-22 | 1981-09-21 | Process to produce pulps |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0060277B1 (en) |
BR (1) | BR8108805A (en) |
DK (1) | DK155192C (en) |
IT (1) | IT1209352B (en) |
WO (1) | WO1982001019A1 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1269806A (en) * | 1985-06-17 | 1990-06-05 | Betzdearborn Inc. | Method of enhancing the cooking of wood chips for pulp production |
FR2684697B1 (en) * | 1991-12-09 | 1996-05-03 | Toulouse Inst Nat Polytech | PROCESS FOR THE MANUFACTURE OF BLEACHED PAPER PULP. |
IN177634B (en) * | 1992-04-06 | 1997-02-15 | Process Improvement Systems Pbc | |
KR20010077423A (en) * | 2000-02-01 | 2001-08-20 | 방윤혁 | Method of manufacturing a regenerated cellulose fiber from the rice straw |
WO2009070955A1 (en) * | 2007-12-05 | 2009-06-11 | Shandong Fuyin Paper & Environmental Protection Technology Co., Ltd | Grass type unbleached paper products and production method thereof |
US8771465B2 (en) * | 2008-12-09 | 2014-07-08 | Shandong Fuyin Paper & Environmental Protection Technology Co., Ltd | Raw Paper |
US8795469B2 (en) * | 2010-06-25 | 2014-08-05 | Prairie Paper Ventures Inc. | Method for preparing nonwood fiber paper |
WO2016062919A1 (en) * | 2014-10-24 | 2016-04-28 | Teknologian Tutkimuskeskus Vtt Oy | Method of processing and fractionating biomass and use of fractions thus obtained |
GB2534589A (en) * | 2015-01-28 | 2016-08-03 | Innovia Films Ltd | Process |
CN116497619A (en) * | 2023-05-17 | 2023-07-28 | 岳阳林纸股份有限公司 | Natural color chemimechanical pulping process for camphorwood sodium hydroxide |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE407816B (en) * | 1973-04-26 | 1979-04-23 | Canadian Ind | PROCEDURE FOR DELIGNIFICATION OF LIGNOCELLULOSE-CONTAINING MATERIAL IN SEVERAL STEPS |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE374769B (en) * | 1970-04-03 | 1975-03-17 | Mac Millan Bloedel Ltd | |
SE355614B (en) * | 1970-05-13 | 1973-04-30 | Mo Och Domsjoe Ab | |
US4045279A (en) * | 1972-01-17 | 1977-08-30 | Toyo Pulp Co., Ltd. | Process for the manufacture of pulp using sodium carbonate and oxygen |
JPS5130601B2 (en) * | 1972-01-17 | 1976-09-02 | ||
SE373896B (en) * | 1972-07-05 | 1975-02-17 | Mo Och Domsjoe Ab |
-
1980
- 1980-09-22 IT IT8024818A patent/IT1209352B/en active
-
1981
- 1981-09-21 BR BR8108805A patent/BR8108805A/en unknown
- 1981-09-21 WO PCT/SE1981/000273 patent/WO1982001019A1/en active IP Right Grant
- 1981-09-21 EP EP81902585A patent/EP0060277B1/en not_active Expired
-
1982
- 1982-05-21 DK DK231182A patent/DK155192C/en active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE407816B (en) * | 1973-04-26 | 1979-04-23 | Canadian Ind | PROCEDURE FOR DELIGNIFICATION OF LIGNOCELLULOSE-CONTAINING MATERIAL IN SEVERAL STEPS |
Non-Patent Citations (1)
Title |
---|
Tappi, Vol. 61, No. 8 issued 1978 August, J.S. Fujii, M.A. Hannah, Oxygen pulping of hardwords s p. 37-40 * |
Also Published As
Publication number | Publication date |
---|---|
BR8108805A (en) | 1982-08-24 |
IT8024818A0 (en) | 1980-09-22 |
DK155192C (en) | 1989-07-10 |
DK155192B (en) | 1989-02-27 |
WO1982001019A1 (en) | 1982-04-01 |
IT1209352B (en) | 1989-07-16 |
DK231182A (en) | 1982-05-21 |
EP0060277A1 (en) | 1982-09-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4793898A (en) | Process for bleaching organic peroxyacid cooked material with an alkaline solution of hydrogen peroxide | |
US4248662A (en) | Oxygen pulping with recycled liquor | |
CA1226705A (en) | Chemithermomechanical pulping process employing separate alkali and sulfite treatments | |
CA2270524C (en) | Method of producing pulp using single-stage cooking with formic acid and washing with performic acid | |
US4076579A (en) | Pulping of lignocellulosic material by sequential treatment thereof with nitric oxide and oxygen | |
EP0060277B1 (en) | Process to produce pulps | |
US5529663A (en) | Delignification of lignocellulosic materials with peroxymonophosphoric acid | |
US5411635A (en) | Ozone/peroxymonosulfate process for delignifying a lignocellulosic material | |
US4248663A (en) | Pulping with an alkaline liquor containing a cyclic keto compound and an amino compound | |
Behin et al. | Dissolving pulp (alpha-cellulose) from corn stalk by kraft process | |
JP2010144273A (en) | Method for producing chemical pulp of lignocellulose material | |
US3919041A (en) | Multi-stage chlorine dioxide delignification of wood pulp | |
Claus et al. | Monoethanolamine (MEA) pulping of beech and spruce wood for production of dissolving pulp | |
EP0250422B1 (en) | Process for preparing bleached pulp from lignocellulosic raw material | |
US3707437A (en) | Pulping and bleaching of wood chips in a single stage with tertiary butyl hydroperoxide | |
EP0022881B1 (en) | Accelerated pulping process | |
US5385641A (en) | Delignification of cellulosic raw materials using acetic acid, nitric acid and ozone | |
CA1177609A (en) | Process to produce pulps | |
Wegener | Pulping innovations in Germany | |
US3773611A (en) | Two-stage sodium sulfite-oxygen pulping | |
Nagar et al. | Different type of paper pulping and process of green bleaching | |
AU7587981A (en) | Process to produce pulps | |
EP2082096B1 (en) | Bleaching of pulp | |
US4787959A (en) | Process for preparing chemical paper pulps by cooking, intermediate grinding and a final alkaline peroxide delignification | |
Lam et al. | Production of paper grade pulp from bagasse by a novel pulping process |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19820608 |
|
AK | Designated contracting states |
Designated state(s): AT DE FR GB NL SE |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT DE FR GB NL SE |
|
REF | Corresponds to: |
Ref document number: 18782 Country of ref document: AT Date of ref document: 19860415 Kind code of ref document: T |
|
ET | Fr: translation filed | ||
REF | Corresponds to: |
Ref document number: 3174191 Country of ref document: DE Date of ref document: 19860430 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 732 |
|
NLS | Nl: assignments of ep-patents |
Owner name: FRANCO NARDI TE CERVIGNANO DEL FRIULI, ITALIE. |
|
NLT1 | Nl: modifications of names registered in virtue of documents presented to the patent office pursuant to art. 16 a, paragraph 1 |
Owner name: SUNDS DEFIBRATOR INDUSTRIES AKTIEBOLAG TE SUNDSVAL |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: TP |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 732 |
|
NLS | Nl: assignments of ep-patents |
Owner name: NACO .P S.R.L. TE CERVIGNANO DEL FRIULI, ITALIE. |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: TP |
|
EAL | Se: european patent in force in sweden |
Ref document number: 81902585.9 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20000907 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 20000911 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20000918 Year of fee payment: 20 Ref country code: FR Payment date: 20000918 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 20000925 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20001026 Year of fee payment: 20 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20010920 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20010921 Ref country code: AT Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20010921 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY Effective date: 20010929 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 Effective date: 20010920 |
|
NLV7 | Nl: ceased due to reaching the maximum lifetime of a patent |
Effective date: 20010921 |
|
EUG | Se: european patent has lapsed |
Ref document number: 81902585.9 |