MXPA98005845A - Additive composition and process to reduce the requirements of anthraquinone in the empulpado of lignocellulos material - Google Patents

Abstract

The present invention relates to an improved preliminary auxiliary composition and a process for the delignification of lignocellulosic raw material, such as wood chips, for the production of cellulose pulps, for the purpose of being used in the manufacture of paper or paperboard, in wherein the wood chips are treated, in a closed reaction vessel, with an alkaline syrup liquor and with an amount of a cyclic keto compound, such as anthraquinone, included therein to achieve a given pulp yield, wherein the improvement comprises a reduction in the amount of anthraquinone required to achieve said yield, by addition to alkaline steaming liquor, in addition to a reduced amount of anthraquinone, of a mixture of surfactants comprising at least one alkyl alcohol alkoxylate and when minus one polyoxyalkylene glycol uni-ether pulley selected from the group consisting of cinoleic acid 12-hydroxystear

Description

ADDITIVE COMPOSITION AND PROCESS TO REDUCE THE REQUIREMENTS OF ANTHRAQUINONE IN THE EMPLOYING OF LIGNOCELLULOSIUM MATERIAL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an improved additive composition, and to a process for the delignification of lignocellulosic material, such as wood, with an alkaline steeping liquor from the kraft or sulphate alkaline pulping process . More particularly, the invention relates to the delignification of lignocellulosic material with kraft cellulose swelling liquors containing a cyclic keto compound (preferably anthraquinone), which allows a better yield. In a specific manner, the invention relates to an improvement of the additive composition, and to a process wherein the best performance is achieved at reduced anthraquinone levels by the inclusion of a mixture of surfactants comprising at least one alcohol alkoxylate. alkyl and at least one polyoxyalkylene glycol ether of an ester of an acid selected from the group consisting of ricinoleic acid and 12-hydroxystearic acid. 2. Description of the Prior Art In the mid-'70s, a significant advance was made in the delignification of lignocellulosic material for the production of wood pulp, upon discovering the benefits of the use of anthraquinone as a liquor additive for liqueurs. of alkaline empulpado. Among the first public disclosures of this use of anthraquinone was U.S. Patent No. 3,888,727, which taught the treatment of lignocellulosic material with an alkaline buffing liquor containing anthraquinone sulfonic acid, followed by delignification with oxygen. However, in a more meaningful way, US Pat. No. 4,012,280 taught that the poorer economy of the soda bleaching process preferable to the environment could be improved to compete with the more offensive kraft pulp process. for the environment (in terms of odor), through the incorporation of anthraquinone as an additive of emulsion. Although the benefits of increased cellulosic pulp performance and increased delignification rate (which allow lower energy consumption and higher production) were demonstrated, the use of the improved soda process with a lower contamination potential did not advance. . First, the incorporation of relatively expensive anthraquinone in the soda process to make it productively competitive with the kraft cellulose process without anthraquinone, reduced its economic competitiveness. Second, the benefits of anthraquinone were also achieved in another process of entrepreneurship (already more commercially employed), such as those employing pulp liquors of kraft cellulose or polysulfide. It was soon discovered, as disclosed in U.S. Patent No. 4,213,821, that anthraquinone also benefited the cooking of wood chips in sulfate neutral sulfate liquor (a special case being disclosed in FIG. U.S. Patent No. 5,139,617), as well as alkaline syrup liquors. Methods for maximizing the benefits of anthraquinone were disclosed in U.S. Patent Nos. 4,127,439; 4,178,861; and 4,310,383. Also, due to the thin, water-insoluble, and unwieldy form of anthraquinone, the discoveries made to facilitate its dispersion in puff liquors are disclosed in U.S. Patent Nos. 4,248,663; 4,384,921; and 4,574,032. One drawback of the use of anthraquinone is its tendency to cause fouling problems in the cooking vessel. Methods for overcoming this problem are disclosed in U.S. Patent Nos. 4,481,073 and 4,561,935. Finally, as a result of the relatively high cost of anthraquinone, methods for recovering and reusing the chemical are disclosed in U.S. Patent Nos. 4,197,168 and 4,310,383.

Despite the aforementioned advances, there remains a need to improve the benefits of anthraquinone treatment (primarily the reduction of energy and chemical requirements while improving performance), and to reduce its drawbacks (primarily the cost and benefits). inlays of the equipment). One approach would be to replace a portion of anthraquinone with an additive that would provide some of the benefits of anthraquinone without providing the drawbacks that accompany its use. Accordingly, an object of this invention is to provide an improved additive composition for puffing, and a process for the delignification of a lignocellulosic raw material, with an anthraquinone swelling liquor, for the production of a predetermined yield of cellulose pulp, whose composition and process to achieve performance, as well as other benefits mentioned above, with a reduced anthraquinone requirement of at least 10 percent. SUMMARY OF THE INVENTION The above-mentioned object is provided by the present invention, which is an improved additive composition and an improved process for the delignification of lignocellulosic raw material, such as wood chips, for the production of cellulose pulps for use in the making paper or cardboard, wherein the wood chips are treated in a closed reaction vessel with a puff liquor, with an amount of a cyclic keto compound, such as anthraquinone, included therein, to achieve a pulp yield determined, wherein the improvement comprises a reduction in the amount of anthraquinone required to achieve this yield, by addition to the alkaline steaming liquor, in addition to a reduced amount of the anthraquinone, of a mixture of surfactants comprising at least one alkoxylate of alkyl alcohol and at least one polyoxyalkylene glycol ether of an ester of a acid selected from the group consisting of ricinoleic acid and 12-hydroxystearic acid. DESCRIPTION OF THE PREFERRED MODALITIES The improved process of this invention comprises the steps of: (1) treating the lignocellulosic material, in a closed reaction vessel, with an alkaline syrup liquor containing an additive of cyclic keto compound selected from the group consisting of naph oquinone, anthraquinone, anthrone, phenanthrenquinone, the alkyl, alkoxy, and amino derivatives of these quinones, 6, 11-dioxo-lH-anthra [1,2-c] pyrazole, anthraquinone-1,2-naph acrylonone, 7,12-dioxo-7, 12-dihydroanthra [1,2-b] pyrazine, 1,2-benzanthraquinone, and 10-methylene nanone, the treatment taking place at a maximum temperature of about 150 ° C to about 200 ° C, for a period of from about 0.5 to about 480 minutes, to achieve a given pulp yield, and (2) displacing the pulping liquor of the lignocellulosic material with water or with an inert aqueous liquor for the lignocellulosic material, in order to obtain a given yield of a delignified cellulosic material, wherein the improvement comprises a reduction in the amount of the additive of cyclic keto compound required to achieve said yield, by addition to the alkaline steeping liquor, in addition to a reduced amount of the cyclic keto compound, of a mixture of surfactants comprising at least one alkyl alcohol alkoxylate and at least one polyoxyalkylene glycol of an ester of an acid selected from the group consisting of ricinoleic acid and acid 12 -. 12 -hydroxystearic. The delignified cellulosic material produced by the two previous steps can be used without further treatment, or can be subjected to conventional bleaching steps. When the lignocellulosic material to be treated is wood, it first becomes the chip form. This step is not required when the lignocellulosic material is of a fibrous form. The lignocellulosic material can be refined between steps (1) and (2). Refining can be done with known equipment, such as a single disk or double disk refiner. The process of this invention can be used to delignify coniferous or deciduous species of wood. Conifera means species such as pine, spruce, and balsam fir. Deciduous means species such as birch, aspen, oriental cottonwood, maple, beech, and oak. The alkyl alcohol alkoxylate component of the surfactant mixture is preferably an alkyl alcohol alkoxylate of 4 to 30 carbon atoms prepared by the reaction of an alcohol, which may have a straight or branched chain, and may be a primary alcohol or secondary, with from about 5 moles to about 100 moles of an alkylene oxide selected from the group of ethylene oxide, propylene oxide, butylene oxide, and any combination thereof. A particular preferred alkyl alcohol alkoxylate is oleyl alcohol ethoxylate prepared with 23 moles of ethylene oxide. The group member of the polyoxyalkylene glycol ethers of an ester of an acid selected from the group of ricinoleic acid and hydroxystearic acid, can be prepared by the reaction of an ester of a glycol, selected from the group of glycerin, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol and its polymers, mannitol, and sorbitol, with from about 5 moles to about 100 moles of an alkylene oxide selected from the group of ethylene oxide, propylene oxide, butylene oxide, and any combination of the same. As long as ricinoleic acid is the primary component (approximately 90 percent) of castor oil, although it is present as a triglyceride rather than being in a free acid form, castor oil can be directly alkoxylated to form the ethers of polyoxyalkylene glycol required from the ricinoleic acid esters. Accordingly, a preferred member of this group is ricinoleic acid triglyceride ethoxylate. U.S. Patent Nos. 5,298,120 and 5,501,769 disclose wood pulping using polyoxyalkylene glycol fatty acid esters to improve pumping uniformity and pulp performance. Although these esters can give the desired performance, there is an inherent weakness in the molecule when it is used in strongly alkaline solutions that are heated at high temperatures. The ester will dissociate and form both a fatty acid soap and the polyalkylene glycol used to form the ester. Accordingly, it ceases to be the claimed ester. Also, the beneficial results are not being produced by the disclosed compound, since in fact, the beneficial results are diminished by the products of this dissociation.

This is not the case with the polyalkylene glycol ethers of the alkyl alcohol and the polyalkylene glycol ether of the claimed ricinoleic acid triglyceride (of castor oil), which can give a superior performance in the strong hot alkaline solutions used in wood pulping. When the ester of the polyalkylene glycol ether of the ricinoleic acid triglyceride is dissociated, the resulting molecule will be the sodium salt of the polyalkylene glycol ether of ricinoleic acid, which is a surfactant, and which will have functionality in the puff solution. The presence of the sodium salt of the polyalkylene glycol ether of the ricinoleic acid will help to solubilize the polyalkylene glycol ethers of the alkyl alcohol in the hot alkaline solution, as the pumping process is carried out. The solubilization of the other surfactants is of great benefit, since, otherwise, these other surfactants can be precipitated out of the solution, and may be less beneficial. The composition of the invention is preferably a microemulsion prepared by the combination of an oleyl alcohol ethoxylate with a ricinoleic acid triglyceride ethoxylate, in a weight ratio of from about 4: 1 to about 1: 4 (preferably about 1 : 2), respectively. For the combination with anthraquinone for use in alkaline surfacing, an aqueous solution of the composition is prepared by mixing with from about 10 to about 30 percent (preferably about 20 percent) of water, yielding a clear viscous solution. In turn, this solution is diluted with water to form from about 10 to about 30 percent (preferably about 12.5 percent) of active when combined with the aqueous anthraquinone dispersion. The surfactant composition of the invention should exhibit a hydrophilic-lipophilic balance of from about 5 to about 20, preferably from about 8 to about 16. By combining the components of the surfactant composition, a microemulsion is formed, which exhibits a particle size. average from about 0.5 to about 10 microns, preferably from about 1 to about 4 microns, and more preferably less than 2 microns. The evidence that a microemulsion of the appropriate average particle size has been formed to realize the synergism observed with anthraquinone is that, by combining the two components at room temperature, a clear solution is formed, and upon heating to about 82 ° C ( 180 ° F), the solution becomes a hazy blue color. The cyclic keto compound, preferably anthraquinone, is preferably prepared as an aqueous dispersion which is combined with the surfactant compound of the invention before its addition to the cooking vessel. The anthraquinone dispersion is preferably prepared by the addition of a dispersant, and by reducing the average particle size of the anthraquinone to about 6 to about 10 microns in water, by wet milling. A preferred dispersant can be a sodium lignosulfonate. Although the surfactant composition and the anthraquinone dispersion can be added separately to the cooking vessel, it is preferred that they are combined before this addition, and then added as a single aqueous mixture. The surfactant microemulsion serves to coat the anthraquinone particles, and allows the mixture of anthraquinone and swelling liquors to penetrate the wood chips at a faster rate, and saturate them in a more efficient and complete manner. It is anticipated that it is this mechanism that results in obtaining the desired kappa number and lower rejections, using significantly less anthraquinone. The benefits of the process and the composition of the invention are seen in the following examples. EXAMPLE 1 For comparison purposes, 59,090 kilograms (sixty-five wet tons) of conifer wood chips were loaded into a sucker digester filled with kraft cellulose alkaline pulp liquors, providing an average of about 4,909 kilograms (approximately 10,800 pounds) of active alkali, in a liquor to wood ratio of approximately 3.45, after which, 22.7 kilograms (50 wet pounds) of a 50 percent anthraquinone dispersion were added. (0.08 percent by weight, based on the weight of the wood chips dried in the oven). The contents of the digester were heated to a maximum temperature of 166 ° C (332 ° F), and the wood chips were baked for 79 minutes to a kappa number of 91. Cooking resulted in a yield of 54 percent, and rejections of 10 percent. Example 2 To be used as an additional digestion aid to improve the benefits of anthraquinone, several samples of the surfactant of the invention were prepared and evaluated to determine the performance of the microemulsion. In different proportions, an oleyl alcohol ethoxylate prepared with 23 moles of ethylene oxide, with a triglyceride ethoxylate of ricinoleic acid and water was combined. In each case, by mixing the components together, a transparent viscous solution was formed.

Sample A: Oleyl alcohol ethoxylate - 20 parts by weight moles of ethylene oxide.

Acid triglyceride ethoxylate 60 parts by ricinoleic weight. Water 20 parts by weight Sample B: Oleyl alcohol ethoxylate - 40 parts by weight moles of ethylene oxide. Triglyceride ethoxylate acid 40 parts by weight ricinoleic. Water 20 parts by weight Sample C: Oleyl alcohol ethoxylate - 23 60 parts by weight moles of ethylene oxide. Acid triglyceride ethoxylate 20 parts by ricinoleic weight. Water 20 parts by weight Each sample was diluted to 12.5 weight percent with water, and heated to 82 ° C (180 ° F). At room temperature, all diluted samples gave clear solutions, and at 82 ° C (180 ° F) each sample became a hazy blue color. Example 3 Again the process of Example 1 was conducted, with the exception that, instead of 0.08 percent anthraquinone, 0.06 weight percent was added, based on kiln-dried wood chips, from an auxiliary digestion comprised of the surfactant mixture of Sample A of Example 2, and anthraquinone, to the white liquor, as the white liquor was simultaneously pumped into the digester, while the wood chips were added. At the end of the digestion cycle, a pulp was produced with a kappa number of 90, with rejections less than 10 percent. Compared with the performance of the anthraquinone alone of Example 1, it is observed that a reduction by 25 percent of digestion aid (using the bombardment additive of the invention) gave a lower kappa number and a significantly lower rejection level . Moreover, when a comparison is made based on the respective anthraquinone content of the respective digestion aids, the surfactant composition of the invention allows a reduction in the required anthraquinone of at least 50 percent. Other advantages of using a digestion aid that has less anthraquinone include: 1. less tendency to scale on the evaporator tubes, and to block the tubes; and 2. reduced contamination of crude tallow oil, which lessens problems in the tallow oil refinery, and reduces contamination of the tallow oil head fraction.

Although the invention has been described and illustrated herein with reference to different specific materials, methods, and examples, it is understood that the invention is not restricted to the particular materials, combinations of materials, and procedures selected for this purpose. Numerous variations of these details may be employed, as will be appreciated by those skilled in the art.

Claims (24)

1. NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, property is claimed as contained in the following: CLAIMS 1. An improved composition of wood pulping, which comprises anthraquinone to be added to liquor liquor in the delignification of lignocellulosic raw material, wherein the improvement comprises the addition of a mixture of surfactants comprising at least one alkyl alcohol alkoxylate and at least one polyoxyalkylene glycol ether of an ester of an acid selected from from the group consisting of ricinoleic acid and 12-hydroxystearic acid.
2. 2. The improved composition according to claim 1, characterized in that the alkyl alcohol alkoxylates are prepared by the reaction of one or more alkyl alcohols of 4 to 30 carbon atoms, with a member of the group of oxides consisting of in ethylene oxide, propylene oxide, butylene oxide, and any combination thereof.
3. 3. The improved composition as claimed in claim 2, characterized in that the alkyl alcohols of 4 to 30 carbon atoms are derived from coconut oil, palm kernel oil, and petroleum.
4. 4. The improved composition according to claim 1, characterized in that the polyoxyalkylene glycol ether of an ester of an acid selected from the group consisting of ricinoleic acid and hydroxystearic acid, is prepared by the reaction of an ester of a glycol selected from the group consisting of glycerin, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol and its polymers, mannitol, and sorbitol, with from about 5 moles to about 100 moles of an alkylene oxide selected from the group of ethylene, propylene oxide, butylene oxide, and any combination thereof.
5. 5. The improved composition according to claim 1, characterized in that the reduction in the amount of the cyclic keto compound required is up to 50 percent.
6. 6. The improved composition according to claim 5, characterized in that the reduction in the amount of the cyclic keto compound required is up to 25 percent.
7. 7. The improved composition as claimed in claim 1, characterized in that the cyclic keto compound is selected from the group consisting of naphthoquinone, anthraquinone, anthra-na, phenanthrenquinone, the alkyl, alkoxy derivatives, and amino of these quinones, 6, 11-dioxo-lH-anthra [1,2-c] pyrazole, anthraquinone-1,2-naphthacridone, 7,12-dioxo-7,12-dihydroanthra [1,2-b] pyrazine , 1,2-benzanthraquinone, and 10-methylenenantrone.
8. 8. The improved composition according to claim 5, characterized in that the cyclic keto compound and the mixture of surfactants are introduced into the alkaline steeping liquor in a simultaneous manner, by means of an aqueous mixture in a proportion of 10%. : 1 to 1:10, respectively.
9. 9. The improved composition as claimed in claim 2, characterized in that the alkyl alcohols of 4 to 30 carbon atoms are selected from the group consisting of primary alcohols and secondary alcohols having a straight or branched chain, and a combination of them.
10. 10. The improved composition according to claim 2, characterized in that the member is reacted in an amount of 5 to 100 moles.
11. 11. The improved composition as claimed in claim 10, characterized in that the member is ethylene oxide.
12. 12. The improved composition according to claim 1, characterized in that the alkaline syrup liquor comprises sodium hydroxide., sodium carbonate, and sodium sulfide.
13. 13. An improved process for the delignification of lignocellulosic raw material in the production of cellulose pulps suitable for use in the manufacture of paper or cardboard, which comprises treating the lignocellulosic raw material in a closed reaction vessel with an alkaline syrup liquor , with an amount of a cyclic keto compound included therein, to achieve a given pulp yield, wherein the improvement comprises a reduction in the amount of the cyclic keto compound required to achieve said yield, by adding to the liquor of alkaline steeping , of a mixture of surfactants comprising at least one alkyl alcohol alkoxylate and at least one polyoxyalkylene glycol ether of an ester of an acid selected from the group consisting of ricinoleic acid and 12-hydroxystearic acid.
14. 14. The improved process according to claim 13, characterized in that the alkyl alcohol alkoxylates are prepared by the reaction of one or more alkyl alcohols of 4 to 30 carbon atoms, with a member of the group consisting of oxides. in ethylene oxide, propylene oxide, butylene oxide, and any combination thereof.
15. 15. The improved process according to claim 14, characterized in that the alkyl alcohols of 4 to 30 carbon atoms are derived from coconut oil, palm kernel oil, and petroleum.
16. 16. The improved process according to claim 13, characterized in that the polyoxylalkylene glycol ether of an ester of an acid selected from the group consisting of ricinoleic acid and 12-hydroxystearic acid is prepared by the reaction of a ester of a glycol selected from the group consisting of glycerin, neopent ilglycol, trimethyl ioletane, trimethylolpropane, pentaerythritol and its polymers, mannitol, and sorbitol, with from about 5 moles to about 100 moles of an alkylene oxide selected from group of ethylene oxide, propylene oxide, butylene oxide, and any combination thereof.
17. 17. The improved process according to claim 13, characterized in that the reduction in the amount of the cyclic keto compound required is up to 50 percent.
18. 18. The improved process according to claim 17, characterized in that the reduction in the amount of the cyclic keto compound required is up to 25 percent.
19. 19. The improved process according to claim 13, characterized in that the cyclic keto compound is selected from the group of compounds consisting of naphthoquinone, anthraquinone, anthrone, phenanthrenquinone, the alkyl, alkoxy, and amino derivatives. of these quinones, 6,11-dioxo-lH-anthra [1,2-c] pyrazole, anthraquinone-1,2-naphthacridone, 7,12-dioxo-7,12-dihydroanthra [1,2-b] pyrazine, 1,2-benzanthraquinone and 10-methylene trone.
20. 20. The improved process according to claim 19, characterized in that the cyclic keto compound and the mixture of surfactants are introduced into the alkaline steaming liquor in a simultaneous manner, by means of an aqueous mixture in a proportion of 10: 1 to 1:10, respectively.
21. 21. The improved process according to claim 14, characterized in that the alkyl alcohols of 4 to 30 carbon atoms are selected from the group consisting of primary alcohols and secondary alcohols having a straight or branched chain, and a combination of them.
22. 22. The improved process according to claim 14, characterized in that the member is reacted in an amount of 5 to 100 moles.
23. 23. The improved process according to claim 22, characterized in that the member is ethylene oxide.
24. 24. The improved process according to claim 13, characterized in that the alkaline slurry liquor comprises sodium hydroxide, sodium carbonate, and sodium sulfide.