US2683090A - Production of wood pulp - Google Patents
Production of wood pulp Download PDFInfo
- Publication number
- US2683090A US2683090A US285244A US28524452A US2683090A US 2683090 A US2683090 A US 2683090A US 285244 A US285244 A US 285244A US 28524452 A US28524452 A US 28524452A US 2683090 A US2683090 A US 2683090A
- Authority
- US
- United States
- Prior art keywords
- copper
- liquor
- cooking
- wood
- production
- 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
- 229920001131 Pulp (paper) Polymers 0.000 title claims description 13
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000010411 cooking Methods 0.000 claims description 28
- 239000002023 wood Substances 0.000 claims description 27
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 13
- 239000004291 sulphur dioxide Substances 0.000 claims description 12
- 235000010269 sulphur dioxide Nutrition 0.000 claims description 12
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 25
- 229910052802 copper Inorganic materials 0.000 description 25
- 239000010949 copper Substances 0.000 description 25
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 14
- 229910021653 sulphate ion Inorganic materials 0.000 description 14
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 13
- 230000015572 biosynthetic process Effects 0.000 description 10
- BWFPGXWASODCHM-UHFFFAOYSA-N copper monosulfide Chemical compound [Cu]=S BWFPGXWASODCHM-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 241000218657 Picea Species 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical group C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 235000007575 Calluna vulgaris Nutrition 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 239000001175 calcium sulphate Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- FMWMEQINULDRBI-UHFFFAOYSA-L copper;sulfite Chemical compound [Cu+2].[O-]S([O-])=O FMWMEQINULDRBI-UHFFFAOYSA-L 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- LPHFLPKXBKBHRW-UHFFFAOYSA-L magnesium;hydrogen sulfite Chemical compound [Mg+2].OS([O-])=O.OS([O-])=O LPHFLPKXBKBHRW-UHFFFAOYSA-L 0.000 description 1
- JESHZQPNPCJVNG-UHFFFAOYSA-L magnesium;sulfite Chemical compound [Mg+2].[O-]S([O-])=O JESHZQPNPCJVNG-UHFFFAOYSA-L 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/22—Other features of pulping processes
- D21C3/222—Use of compounds accelerating the pulping 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
- D21C3/224—Use of means other than pressure and temperature
Definitions
- PRODUCTION oF woon PULP Filed April 30, 1952 JHM/Kif ma v 2 l j :KfW/5P] /m/enfors AH190' Crow/herA/a'red Geofe Burda/#Tamer
- the object of the present invention is to inhibit or reduce the formation of sulphate during the cooking.
- the cooking liquor in a process for the production of wood pulp by cooking wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the cooking liquor is maintained in contact with copper in order to inhibit or reduce the formation of sulphate during the cooking.
- the process of this invention is preferably carried out by continuously circulating the sulphite liquor through a closed system comprising a vessel containing the wood, one or more heaters, a second vessel containing the copper, which may conveniently be in the form of gauze or lings that is to say, in a discrete form having large surface area, and a separating device, for example a lter, for removing copper sulphite from the liquor.V
- a separating device for example a lter
- a circulatory system suitable for use in the present invention is shown in the accompanying drawing.
- the wood chips are packed in a vessel l, conveniently made of stainless steel and the sulphite liquor is continuously circulated through the vessel I, through an external heater 2, a pump 3, a second heater 4, a container 5 containing copper, a lter 6 to remove copper sulphide and back into the vessel l. y,
- the container for the wood, the container for the copper and the filter may be built up in a single container having three separate but connected compartments.
- this reaction is catalysed by metals such as iron, cobalt, molybdenum, manganese and zinc, many of which are used in construction materials for the cooking vessels, andby many substances either present in the Wood or formed during the cooking.
- metals such as iron, cobalt, molybdenum, manganese and zinc
- the sulphate formation is effectively reduced.
- the present invention in general gives increased yields of dry pulp.
- the copper is converted during the cooking into copper sulphide which may be recovered if desired, for example from the lter 6, and reconverted into copper for use in a subsequent cook.
- Example 1 1 part of spruce Wood chips, 0.005 part of copper filings and 4.5 parts of a sulphite liquor containing 5 per cent total sulphur dioxide and 1.3 per cent combined sulphur dioxide in the form of magnesium sulphite were cooked in a stainless steel vessel, the temperature being rst raised to centigrade and kept at this point for 3 hours whereupon the temperature was raised over 1/2 hour to 150 centigrade and then kept at this point for 2 hours 40 minutes.
- the waste liquor from this cook was found to contain 0.06 per cent of sulphate and the yield of dry pulp was 4'7 per cent of the weight of the vdry wood whereas in a similar cook carried out without the addition of the copper filings, 0.13 per cent of sulphate was present in the waste liquor, and the yield of dry wood pulp was 45.4 per cent.
- Example 2 In this example a circulatory system as described in the drawing was used.
- the sulphate content of the liquor at the end of the cook was 0.2 per cent
- the ligure for a similar run in the yabsence of copper was within the range of 0.5 to l per cent.
- the yield in Example 2 was 47 per cent kof dry pulp based on the weight of the dry wood, a yield which is generally higher than that obtained in the absence of the copper.
- a process for the production of wood pulp by cooking Wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide comprising continuously circulating the sulphite liquor through a closed system comprising a vessel containing the wood, at least one heater, a second vessel containing metallic copper in discrete form and a separating device to remove copper sulphide from the liquor before the liquor is passed through the wood pulp 4 whereby the formation of sulphate during the cooking is reduced.
- step 5 which comprises maintaining the cooking liquor in contact with from 0.05 to 1.0% of copper 'based on the weight of the wood chips, said copper being in a discrete physical form having a large surface area whereby formation Vof .sulphate during the cooking is reduced.
- step 8 which comprises maintaining the cooking liquor in contact with from 0.05 to 1.0% of copper gauze based on the weight of the wood chips, whereby formation of sulphate during the cooking is reduced.
Description
July v6, 1954 F. c. ALDRED ET AL 2,583,090
PRODUCTION oF woon PULP Filed April 30, 1952 JHM/Kif ma v 2 l j :KfW/5P] /m/enfors AH190' Crow/herA/a'red Geofe Burda/#Tamer By file/'r a fomeys Patented .luly 6, 1954 l f y 2,683,090
IRODUCTION OF WOOD PULP Fred C. Aldred, Coventry, and Geoffrey B. Turner, Green Lane, Coventry, England, assignors to Courtaulds Limited, London, England, a British Company Application April 30, 1952, Serial No. 285,244
Claims priority, application Great Britain June 21, 1951 8 Claims. (Cl. 92--11) This invention relates to the production of Wood pulp.
In the production of wood pulp by the so-called sulphite process, wood chips are cooked with a liquor consisting of an aqueous solution of a bisulphite, usually calcium or magnesium bisulphite, containing excess sulphur dioxide. Although the cooking reaction is complex it is generally accepted that the cooking treatment converts the lignin inthe wood into ligno-sulphonic acid which is then hydrolysed into soluble or readily dispersable aggregates. During the cooking the sulphite liquor tends to decompose with the formation of sulphate and it is believed that some of the known undesirable effects of prolonging a sulphite cook, such as excessive degradation of the cellulose in the wood, are due to sulphate or other products of this decomposition.
It is also known to circulate the sulphite liquor continuously through the wood chips by means of a circulatory system including one or more heat exchangers. The presence of calcium sulphate in the liquor causes scale formation in the pipes and the heat exchangers vand this scaling is difficult to lremove.y TheV difficulty due to scaling is particularly serious when attempts are made to concentrate the Waste liquor prior to further treatment.
The object of the present invention is to inhibit or reduce the formation of sulphate during the cooking.
According to the present invention, in a process for the production of wood pulp by cooking wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the cooking liquor is maintained in contact with copper in order to inhibit or reduce the formation of sulphate during the cooking.
The process of this invention is preferably carried out by continuously circulating the sulphite liquor through a closed system comprising a vessel containing the wood, one or more heaters, a second vessel containing the copper, which may conveniently be in the form of gauze or lings that is to say, in a discrete form having large surface area, and a separating device, for example a lter, for removing copper sulphite from the liquor.V The use of such a system prevents the contamination of the pulp by copper sulphide. The process of Ithe inventionmay however be carried out by heating the wood, the sulphite liquor and copper together in a single vessel.`
A circulatory system suitable for use in the present invention is shown in the accompanying drawing. The wood chips are packed in a vessel l, conveniently made of stainless steel and the sulphite liquor is continuously circulated through the vessel I, through an external heater 2, a pump 3, a second heater 4, a container 5 containing copper, a lter 6 to remove copper sulphide and back into the vessel l. y,
In a modification the container for the wood, the container for the copper and the filter may be built up in a single container having three separate but connected compartments.
Experiments which we have carried out have shown that the overall decomposition of the sulphite liquor is probably in accordance with the following reaction:
We have found that this reaction is catalysed by metals such as iron, cobalt, molybdenum, manganese and zinc, many of which are used in construction materials for the cooking vessels, andby many substances either present in the Wood or formed during the cooking. By maintaining the sulphite liquor in contact with a small amount, for example from 0.05 to 1.0 per cent of copper, based on the weight of the wood chips, in accordance with this invention the sulphate formation is effectively reduced. In addition to the sulphate reduction the present invention in general gives increased yields of dry pulp.
The copper is converted during the cooking into copper sulphide which may be recovered if desired, for example from the lter 6, and reconverted into copper for use in a subsequent cook.
The invention is illustrated by the following examples in which parts and percentages are by weight:
Example 1 1 part of spruce Wood chips, 0.005 part of copper filings and 4.5 parts of a sulphite liquor containing 5 per cent total sulphur dioxide and 1.3 per cent combined sulphur dioxide in the form of magnesium sulphite were cooked in a stainless steel vessel, the temperature being rst raised to centigrade and kept at this point for 3 hours whereupon the temperature was raised over 1/2 hour to 150 centigrade and then kept at this point for 2 hours 40 minutes. The waste liquor from this cook was found to contain 0.06 per cent of sulphate and the yield of dry pulp was 4'7 per cent of the weight of the vdry wood whereas in a similar cook carried out without the addition of the copper filings, 0.13 per cent of sulphate was present in the waste liquor, and the yield of dry wood pulp was 45.4 per cent.
Example 2 In this example a circulatory system as described in the drawing was used.
1 part of spruce Wood chips was packed into the container l and the container 4 was packed with copper gauze. A sulphite liquor containing 6 per cent total sulphur dioxide and 1.2 per cent combined sulphur dioxide in the form of sodium sulphite was, continuously circulated through the system, the ratio of liquor to wood being 4.5 1. The heaters were adjusted so that the temperature of the liquor rose to 110 centigrade in 11/2 hours, this temperature being maintained for 21/2 hours; the temperature was then raised over 11/4 hours to 150 centigrade and this temperature was maintained for 1 hour 40 minutes. The maximum pressure throughout was 120 lb./in.2.
The sulphate content of the liquor at the end of the cook was 0.2 per cent Whereas the ligure for a similar run in the yabsence of copper was within the range of 0.5 to l per cent. The yield in Example 2 was 47 per cent kof dry pulp based on the weight of the dry wood, a yield which is generally higher than that obtained in the absence of the copper.
What we claim is:
l. In a process for the production of wood pulp by cooking wood chips with an aqueous solution of a bisulphite'containing excess sulphur dioxide, the step comprising maintaining the cooking liquor in contact with metallic copper in discrete form whereby the formation of sulphate during the cooking is reduced.
2. In a process for the production of wood pulp by cooking Wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the steps comprising continuously circulating the sulphite liquor through a closed system comprising a vessel containing the wood, at least one heater, a second vessel containing metallic copper in discrete form and a separating device to remove copper sulphide from the liquor before the liquor is passed through the wood pulp 4 whereby the formation of sulphate during the cooking is reduced.
3. The process as claimed in claim 1 wherein the copper is in the form of copper filings.
4. The process as claimed in claim 1 wherein the copper is 'in the form of copper gauze.
5. In a process for the production of Wood pulp by cooking Wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the step which comprises maintaining the cooking liquor in contact with from 0.05 to 1.0% of copper 'based on the weight of the wood chips, said copper being in a discrete physical form having a large surface area whereby formation Vof .sulphate during the cooking is reduced.
6. A process as claimed in claim 5 wherein the sulphite liquor is continuously circulated through a closed system comprising a rst stage wherein the Wood chips are digested with the cooking liquor, a second stage wherein the cooking liquor is heated, a third stage wherein the liquor is contacted with the copper, and a fourth stage wherein the liquor having contacted the copper is treated to remove copper sulphide.
'7. In a process for the production of wood pulp by cooking wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the step which comprises maintaining the cooking liquor in contact with from 0.05 to 1.0% of copper filings based -on the weight of the Wood chips, whereby formation of sulphate during the cooking is reduced.
8. In a process for the production of wood pulp by cooking wood chips with an aqueous solution of a bisulphite containing excess sulphur dioxide, the step which comprises maintaining the cooking liquor in contact with from 0.05 to 1.0% of copper gauze based on the weight of the wood chips, whereby formation of sulphate during the cooking is reduced.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 360,484 Schnurmann et al. Apr. 5, 1887 483,942 Radford Oct. 4, 1892
Claims (1)
1. IN A PROCESS FOR THE PRODUCTION OF WOOD PULP BY COOKING WOOD CHIPS WITH AN AQUEOUS SOLUTION OF A BISULPHITE CONTAINING EXCESS SULPHUR DIOXIDE, THE STEP COMPRISING MAINTAINING THE COOKING LIQUOR IN CONTACT WITH METALLIC COP-
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB14727/51A GB703102A (en) | 1951-06-21 | 1951-06-21 | Improvements in and relating to the production of wood pulp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2683090A true US2683090A (en) | 1954-07-06 |
Family
ID=10046409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US285244A Expired - Lifetime US2683090A (en) | 1951-06-21 | 1952-04-30 | Production of wood pulp |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2683090A (en) |
| GB (1) | GB703102A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4670098A (en) * | 1984-12-21 | 1987-06-02 | Mo Och Domsjo Ab | Process for preparing cellulose pulp from lignocellulosic material while removing high molecular weight substances from the pulping liquor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US360484A (en) * | 1887-04-05 | sohnuemann | ||
| US483942A (en) * | 1892-10-04 | Digester |
-
1951
- 1951-06-21 GB GB14727/51A patent/GB703102A/en not_active Expired
-
1952
- 1952-04-30 US US285244A patent/US2683090A/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US360484A (en) * | 1887-04-05 | sohnuemann | ||
| US483942A (en) * | 1892-10-04 | Digester |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4670098A (en) * | 1984-12-21 | 1987-06-02 | Mo Och Domsjo Ab | Process for preparing cellulose pulp from lignocellulosic material while removing high molecular weight substances from the pulping liquor |
Also Published As
| Publication number | Publication date |
|---|---|
| GB703102A (en) | 1954-01-27 |
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