CA2578305A1 - Process for recovery of oligosaccharides and polysaccharides during pulping - Google Patents
Process for recovery of oligosaccharides and polysaccharides during pulping Download PDFInfo
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- CA2578305A1 CA2578305A1 CA002578305A CA2578305A CA2578305A1 CA 2578305 A1 CA2578305 A1 CA 2578305A1 CA 002578305 A CA002578305 A CA 002578305A CA 2578305 A CA2578305 A CA 2578305A CA 2578305 A1 CA2578305 A1 CA 2578305A1
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- Prior art keywords
- sop
- aliphatic alcohol
- digester
- alkaline
- alcohol
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H3/00—Compounds containing only hydrogen atoms and saccharide radicals having only carbon, hydrogen, and oxygen atoms
- C07H3/06—Oligosaccharides, i.e. having three to five saccharide radicals attached to each other by glycosidic linkages
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H1/00—Processes for the preparation of sugar derivatives
- C07H1/06—Separation; Purification
- C07H1/08—Separation; Purification from natural products
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L97/00—Compositions of lignin-containing materials
- C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
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- 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
- D21C1/00—Pretreatment of the finely-divided materials before digesting
- D21C1/06—Pretreatment of the finely-divided materials before digesting with alkaline reacting compounds
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- 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
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- 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
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- 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
- D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
Abstract
Solid Oligosaccharides and Polysaccharides (SOP) are obtained through the SOP
process. Chips or finer particles of raw wood are extracted with a warm alkaline solution at or near ambient pressure in a pulp-mill digester. The alkaline extract is transferred from digester to a holding/stirring tank, and the wood particles in the digester are then pulped as usual. SOP forming upon addition of alcohol to the alkaline extract may be concentrated either by centrifugation or filtration, washed, dehydrated and packaged. The process also enables SOP bleaching. Dry unbleached or bleached SOP can be readily dissolved in water for further processing. Alcohol is recovered by distillation, and residual alkali is returned to the digester for treatment of the next batch of wood. Potential uses of SOP are multi-faceted, e.g., as digestive fibre, gum, paper or paper additive, pharmaceutical bulking agent, well-drilling, ethanol or energy production.
process. Chips or finer particles of raw wood are extracted with a warm alkaline solution at or near ambient pressure in a pulp-mill digester. The alkaline extract is transferred from digester to a holding/stirring tank, and the wood particles in the digester are then pulped as usual. SOP forming upon addition of alcohol to the alkaline extract may be concentrated either by centrifugation or filtration, washed, dehydrated and packaged. The process also enables SOP bleaching. Dry unbleached or bleached SOP can be readily dissolved in water for further processing. Alcohol is recovered by distillation, and residual alkali is returned to the digester for treatment of the next batch of wood. Potential uses of SOP are multi-faceted, e.g., as digestive fibre, gum, paper or paper additive, pharmaceutical bulking agent, well-drilling, ethanol or energy production.
Description
SPECIFICATION
The process claimed herein produces dehydrated solid oligosaccharides and polysaccharides (SOP) from chemical substances resident within raw wood particles. Any chemical or semi-chemical process of wood pulping involving use of alkaline liquor in the digester is compatible with the SOP
process. As indicated in the DRAWINGS (Fig. 1), the SOP process includes capability for washing and bleaching of SOP and recovery of the liquids used in the process. In addition, once SOP has been produced by the process, it can be readily transformed into a clear solution of oligosaccharides and polysaccharides merely by mixing dehydrated SOP with water.
The novelty of the SOP process goes beyond linking together a series of existing technologies in the correct sequence needed to provide large quantities of SOP
for use in various commercial production streams. The black liquor issuing from the digester after pulping contains not only sulfonated lignin derivatives but also sulfonated and otherwise chemically modified compounds derived from the hemicellulose fraction of wood (Niemela 1990 - full references are given in the Literature Cited section before the Claims). By removing soluble and/or miscible oligosaccharides and polysaccharides at the beginning of the pulping process, a significant fraction of wood substance is prevented from contributing to the black liquor stream.
SOP, unbleached or bleached, is the deliverable from the SOP process.
Potential end uses of SOP are multi-faceted but not the subject of this Specification. SOP may well be found directly useful for production of novel kinds of paper (e.g., water-soluble paper) and is expected to find application as a paper additive (i.e., as a sizing). SOP as an intermediate product will, upon further processing, likely find use in applications such as food (digestive fiber), chewing and other gums, bulking agent in well-drilling, ethanol, energy production, and many other end products.
Background and Prior Art. The first writing/drawing paper was made by the Egyptians from the lowermost stem parts of papyrus, a sedge that grows up to 5 m in height, using a semi-pulping process involving stem slicing, pounding, cross-lapping and drying (Hunter 1947). Thus, the word "paper" is derived from the Greek and Latin words papuros and papyrus, respectively. The production of paper from papyrus exploited the natural ability of cellulose present in cell walls of all plant fibrous elements to bond together even when the plant tissue's adjoining fibres remain intact, but "true' paper is made from plant tissues that have been reduced to their individual fibres (i.e., fully pulped) and then re-constituted from a fibrous pulp suspension. True paper was being produced manually in China as early as the 2nd century BC, by pounding wetted cloth rags and/or Page 3 of 3 bark to pulp, using a screen to lift the pulp out of the pulp vat and produce a wet layer of pulp, followed by pressing absorbed moisture out and then hanging and drying that `sheet' into paper.
Many centuries of paper-making followed (Hunter 1947).
Wood as it occurs in logs is a relatively hard bulky and inflexible material;
therefore, at the outset of paper-making, wood was likely given no consideration as a material for manually pounding into pulp. Use of wood for paper-making evidently was first suggested in 1719 by Rene Antoine Ferchault de Reaumur following his observations of papery nests created by American and Canadian wood wasps. Nevertheless, it was not until 1765 that Jacob Christian Schaffer made papers from pulp of beech, willow, aspen, mulberry, spruce and other woods, each paper being produced from wood pulp in admixture with rag fibres. Schaffer also noted that wood treated with a lime paste required less time and energy to beat into pulp than untreated wood, and this evidently was the first step toward chemical pulping of wood.
The first paper originating entirely from wood pulp appears to have been a single page made of elm-wood fibres and produced in 1786 by Leorier Delisle (in a book authored by Charles Michel de Villette). In 1798 Nicolas-Louis Robert constructed a moving screen belt capable of receiving a continuous flow of pulp suspension and delivering an unbroken sheet of wet paper to a pair of squeeze rolls where most of the residual liquid was removed from the adjoining fibres, and that innovation set the stage for mass production of paper hence the demand for larger quantities of pulp than could be produced manually. In 1800 the Great Seal Patent office, London, granted Matthias Koops a patent "...for a method of manufacturing paper from straw, hay, thistles, waste, and ruse of hemp and flax, and different kinds of wood and bark." In 1840 Friedrich Gottlob Keller secured a German patent for grinding logs against a millstone and, in 1867, ground-wood pulp was being produced in Massachusetts in order to make newsprint solely from wood fibres.
Newsprint as produced from chemically untreated ground wood was dull, darkened quickly and was not very strong, and the desire to produce stronger, brighter paper from wood led to investigations into chemical pulping. The first chemical pulping of wood to operate on the industrial scale was the soda process, so-named because it uses sodium hydroxide (NaOH) as the cooking agent. The soda process was developed in 1851 by Hugh Burgess and Charles Watt in England, and they secured a USA patent for the process in 1854. Alkaline sulfite pulping was patented in 1867 by Benjamin Tilghman in the USA, and Kraft pulping was patented in 1884 by Carl Dahl of Germany.
Many variations on those chemical pulping processes have subsequently been described, and innumerable patents exist in relation to their modifications. One variation presently invoking Page 4 of 4 considerable interest is known as ASAM pulping (alkaline sulfite with anthraquinone and methanol), described by Patt and Kordsachia (1986). The SOP process is compatible with digesters using soda, alkaline sulfite, Kraft or ASAM chemical, semi-chemical or chemi-mechanical pulping.
All chemical and related pulping processes are concerned with one or more direct or ancillary aspects of the treatment of wood particles with harsh chemicals at high temperature and pressure for extended periods, the aim being to break the chemical bonds between lignin, hemicelluloses and cellulose in order that the individual woody elements, usually referred to as `fibres', can exist independently and generate a useable pulp. Because chemical methods of pulping require that the wood particles be treated for several hours above atmospheric pressure at a temperature above the boiling point (approximately 100 C) of the cooking liquor, a pressure cooker known as a`digester' is used and is the starting point of the pulping process.
Under the harsh conditions associated with cooking wood particles within a digester, not only lignins but a variety of compounds collectively but non-specifically referred to as `hemicelluloses' are hydrolyzed within the wood cell walls and released into the cooking liquor. In recent years, wood hemicelluloses have been identified as an important material for manufacture of ethanol, and various patents related to ethanol production from sugars derived from hemicelluloses have been filed.
However, to the best of my knowledge none of those patents has addressed development of an industrial process such as described herein, for obtaining from a relatively mild alkaline solution applied to wood particles within a pulp-mill digester oligosaccharides and polysaccharides before those substances become part of the waste black liquor stream.
The use of an aliphatic alcohol to coagulate or "precipitate" polysaccharides in an alkaline solution gained acceptance as a routine scientific method, of common knowledge in the public domain, early in the 20th century (e.g., Norris and Preece 1930; Sands and Gary 1933; Adams and Castagne 1951). Following upon that scientific advance, several patents were nevertheless awarded specifically in relation to use of an aliphatic alcohol, such as ethanol, to precipitate "hemicelluloses"
from alkaline extracts of plant tissues. For example, US patent 3935022 for the manufacture of viscose products claimed "a process for removing hemicelluloses from hemicellulose-containing alkali solution consisting essentially of adding to said alkali solution a sufficient amount of a solvent consisting essentially of ethanol to precipitate hemicellulose from said alkali solution..." Similarly, US patent 7101996 claimed "a process for the separation of purified hemicelluloses from insoluble cellulose and cellulose-hemicellulose complexes in caustic liquor from solubilizing fiber with alkali comprising the steps of adding alcohol to the caustic liquor to precipitate the hemicelluloses..."
Page 5 of 5 However, the supposed inventions underlying those claims were already in the public domain.
Moreover, the details of practicable industrial processes were not specified as such in those patents.
In addition, there has been a tendency in the patent literature for the term `hemicellulose' to be used unclearly, although the meaning of the term has been more rigorously interpreted (Aspinall 1970, Wilkie 1985). As noted by Wilkie (1985), "Confusion and uncertainty is caused when terms are used that are ill-defined or, as in the case of hemicelluloses, when terms have considerable, and unrecognized, variability in their defmition."
The Claims made herewith embody a practicable industrial process for obtaining a mixture of solid oligosaccharides and polysaccharides (SOP) in major quantity from raw wood particles during pulping involving the use of an alkaline solution in the digester. For brevity, it is referred to as the 'SOP process'. The embodiments of the SOP process require that a distinction be made between the natural hemicelluloses of wood and the oligosaccharides and polysaccharides obtained by the SOP process. Aqueous alkaline treatment of cell walls of woody elements not only hydrolyzes into smaller molecules those substances referred to as hemicelluloses but also saponifies the natural esters (e.g., acetyl or diferulyl groups) which are natural to the hemicelluloses. In other words, alkali extraction changes the true or `native' hemicelluloses of wood into de-esterified polysaccharides and shorter oligosaccharides differing in both chemical properties and chain length from those occurring naturally in wood (Neilson and Richards 1978). One way to understand the distinction is to consider the solubility of hemicelluloses vis-a-vis solid oligosaccharides and polysaccharides (SOP) obtained by the SOP process. In general native hemicelluloses will produce a cloudy suspension rather than a clear solution when mixed with cool or lukewarm water. SOP, on the other hand, upon mixing with water at sub-ambient or higher temperature, quickly provides a clear solution of oligosaccharides and polysaccharides. In other words, the colligative properties of SOP are different from those of native hemicelluloses.
In developing this invention referred to as the SOP process, a variety of woody plant species - 39 tree species and 2 additional species (viz., bamboo and cotton) - growing worldwide was investigated (Fig. 2). Based on that research, it can be concluded that many, possibly all, woods will yield some amount of SOP when subjected to the SOP process. However, as shown in Figure 2, the yield clearly varies among species, with Magnoliophyta in general providing more SOP than Coniferophyta. Of the species investigated, bamboo stems yielded the most SOP, raw fibres of the cotton boll the least (Fig. 2).
Page 6 of 6 The chemistry of SOP from Betula populifolia wood was investigated in some depth, by dialysis followed by sulfuric acid hydrolysis of the SOP followed by barium carbonate neutralization, drying, trimethylsilylation and analysis by combined gas chromatography - mass spectroscopy (GC/MS). Dialysis through cellulose acetate of different molecular-weight cutoffs established that B. populifolia SOP comprises short-chain oligosaccharides as well as polysaccharides. GC/MS of hydrolyzed trimethylsilylated SOP revealed that both the oligosaccharides and polysaccharides contain equal amounts of D-xylose and a second equally abundant monosaccharide the precise identity of which could not be unequivocally established.
Preliminary investigations indicate that those two compounds characterize Magnoliophyta SOP in general; however, considerable research remains to be done on the chemical properties of SOP.
The SOP process embodies the requirement for sequential, correctly ordered, precise and economically efficient use of a number of existing technologies, viz., 1) conversion of logs into particles of wood, 2) conveyance of a known weight of those wood particles into the cooking chamber of a pulp-mill digester, 3) preparation of a defmed alkaline solution of known molarity, 4) conveyance of a known volume of defined alkaline solution of known molarity to the wood particles within the cooking chamber, 5) warming of the alkaline solution within the cooking chamber to a known temperature and maintaining the digester's cooking chamber at that temperature for a known time, 6) removing a known volume of the alkaline solution from the cooking chamber and transferring that volume to a tank capable of stirring the alkaline solution at ambient temperature, 7) stirring the known volume of alkaline solution in the tank at ambient temperature and, while stirring, adding to the volume of alkaline solution an equal volume of an aliphatic alcohol at ambient temperature in order to create a suspension of SOP, 8) transferring the SOP
suspension in a regulated way from the tank to a mechanical device (e.g., a filter-lined centrifuge, a paper-making wire, a vacuum-filtration system, or a gravity-feed filtration system) capable of separating solids from liquids followed by washing of the solids, 9) repeating steps 3 - 8 a second time to achieve a higher SOP yield, 10) if desired, bleaching SOP with hydrogen peroxide in a defmed solution of known concentration at known temperature for a known time, 11) whether or not SOP is bleached as per step 10, dehydrating SOP using either aliphatic alcohol or air drying, 12) distilling the liquid removed from the SOP suspension in order to reuse the aliphatic alcohol and alkaline solutions, 13) further processing of the SOP including treatment with a known volume of water per unit mass of solid in order to produce clear solutions, 14) packaging and/or sale of the SOP, 15) pulping the residue of wood particles remaining in the digester following completion of step 9.
Page 7 of 7 List of Figures and Tables.
Figure 1. Sequential steps of the SOP process when using 2.5 M NaOH, ethanol and a vertical axis basket continuous centrifuge. Chemical recovery/recycling operations follow step 8.
Figure 2. Percentage yield of SOP from dry, raw wood particles of 36 Magnoliophyta and 2 Coniferophyta species; bars indicate standard deviations for 3 replicate investigations.
Figure 3. Percentage yield of SOP from dry, raw wood as a function of temperature and NaOH
molarity, based on Betula populifolia wood particles.
Table 1. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles for different time periods with 1 M NaOH at 25 C;
standard deviations (s.d.) are for 3 replicate investigations.
Table 2. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles for 1 hour at 50 C;, comparing NaOH molarities;
standard deviations (s.d.) are for 3 replicate investigations.
Table 3. Dehydrated SOP yields (% of dry, raw wood weight) after extracting different sizes of dry, raw Betula populifolia wood particles once or twice for different time periods with 2.5 M NaOH at 50 C; standard deviations (s.d.) are for 3 replicate investigations.
Table 4. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles once or twice for different time periods with 2.5 M
NaOH at 50 C;
standard deviations (s.d.) are for 3 replicate investigations.
Table 5. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with 2.5 M NaOH for one hour at 50 C; and adding an equal volume of an aliphatic alcohol to generate a SOP suspension; standard deviations (s.d.) are for 3 replicate investigations.
Table 6. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with 1.0 M NaOH or 2.5 M NaOH at 50 C and adding the indicated volume of ethanol to generate a SOP suspension; standard deviations (s.d.) are for 3 replicate investigations.
Table 7. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with four kinds of alkali at 1.0 M or 2.5 M
concentrations for 1 hour at 50 C; standard deviations (s.d.) are based on 3 replicate investigations.
Page 8 of 8 Table 8. Yields (% of weight of dry, raw Betula populifolia wood particles) of unbleached and bleached (3% H202 for 10 minutes at ambient temperature) dehydrated SOP
retained by a cellulosic filter following centrifugation at 500 X g; standard deviations (s.d.) are for 3 replicate investigations.
Table 9. Weight change of dehydrated SOP (% of the weight of dehydrated Betula populifolia raw SOP based on the yield provided using 50% ethanol) in relation to incremental increases in ethanol concentration during centrifugation, always in the presence of 2.5 M NaOH;
standard deviations (s.d.) are for 3 replicate investigations.
Table 10. Bleached (3% H202 for 10 minutes at ambient temperature) and unbleached dehydrated SOP yields (% of weight of dry, raw wood particles) from woods of several tree species; standard deviations (s.d.) are for 3 replicate investigations.
Page 9 of 9 An Example of Use Based on Wood of Grey Birch Figure 1 indicates the stepwise progression of the SOP process using 2.5 M
NaOH at 50 C in the digester, ethanol in the SOP-forming tank, and a vertical axis basket industrial centrifuge to separate, wash and bleach SOP. These conditions were identified as optimal for Betula populifolia (grey birch) wood particles, based on data displayed in the DRAWINGS (Fig. 3, Tables 1-10). The process shown in Figure 1 is explained as follows:
STEP 1: A pulp-mill batch digester is loaded with clean debarked particles of raw wood. The particles may be the size of chips, but a higher yield of SOP will be obtained from smaller particles and the highest yield from ground-wood fibres or sawdust (see DRAWINGS: Table 3).
STEP 2: The digester is filled with 2.5 M NaOH (4 litres or more of NaOH
solution per kilogram of dry wood). The digester's internal temperature is raised to 50 C and held for one hour, allowing the extraction of soluble and miscible substances from the wood particles to proceed under static conditions. As shown in DRAWINGS (Fig. 3), SOP yield would be higher at temperatures above 50 C.
STEP 3: The `1-h 50 C extract' arising from STEP 2 is transferred from the digester into a SOP-forming tank containing a stiurer and maintained under ambient conditions. It was determined by investigation of wood particles tightly packed into a vertical column (simulating a digester) that, following STEP 2, transfer of the 1-h 50 C extract from the digester will proceed by either gravity flow or upward displacement.
STEP 4: In order to increase the yield of SOP, immediately following the STEP
3 transfer of the 1-h 50 C extract to the SOP-forming tank, to the wood particle residue remaining in the digester is added a second volume of 2.5 M NaOH (see DRAWINGS: Table 4). Four litres of NaOH solution per kilogram of dry wood was found to be the optimal ratio. The digester internal temperature is raised to 50 C and held for one hour, allowing the extraction of soluble and miscible substances from the wood particles to proceed under static conditions.
STEP 5: The `2-h 50 C extract' arising from STEP 4 is transferred from the digester into either the same SOP-forming tank containing the 1-h 50 C extract or a second identical SOP-forming tank. It was determined by investigation of wood particles tightly packed into a vertical column (simulating a digester) that, following STEP 4, transfer of the 2-h 50 C extract from the digester will proceed by either gravity flow or upward displacement. Upon completing the transfer of the 2-h 50 C extract from the digester to a SOP-forming tank, if the wood particle residue in the digester constitutes wood chips, pulping follows by addition of the white liquor normally used in the chip-pulping Page 10 of 10 process. If the wood particles loaded into the digester is ground wood or sawdust, depending on the intended end use it may be considered that no additional digester pulping is needed and that the fibres can be mechanically separated (not shown in Fig. 1) and processed for their end purpose.
STEP 6: To the volume of 1-h 50 C extract and/or 2-h 50 C extract in the SOP-forming tank is added an equivalent volume of ethanol from the ethanol tank (see DRAWINGS:
Tables 5 and 6).
The stirrer in the SOP-forming tank is activated for one minute to vigorously mix the ethanol and 1-h 50 C extract and/or 2-h 50 C extract. The mixture is then permitted to sit for at least one hour under ambient, static conditions whereupon solid oligosaccharide and polysaccharides (SOP) precipitate. The resulting suspension in the SOP-forming tank is then continuously stirred, and while being actively stirred the SOP suspension is transferred from the SOP-forming tank by either pumping or gravity flow to an actively spinning continuous vertical axis basket centrifuge, said centrifuge basket being fitted with a cellulose-based filter.
STEP 7: At this step, the option exists to generate washed unbleached SOP via STEP 7A or washed bleached SOP via STEP 7B. In general, the yield of bleached dehydrated SOP is lower than that of unbleached SOP (see DRAWINGS: Table 8, Table 10).
STEP 7A: The angular velocity of the vertical axis basket centrifuge is set such that the spinning vertical axis basket provides a centripetal force equivalent to 500 X g. A
higher g force is acceptable, but 500 X g was determined to be satisfactory. Centrifugation results in the incoming SOP from the SOP-forming tank being packed against the vertical axis basket filter while the suspension's clear liquid with its solutes is dispelled through the filter and transferred to a SOP-liquid receiving tank. When the vertical axis basket centrifuge has accumulated a full load of SOP, the feed valve from the SOP-forming tank is closed to stop transfer of any additional SOP slurry into the centrifuge basket. With the centrifuge vertical axis basket still spinning to provide 500 X g (or more), SOP in the basket is washed briefly by injecting into the spinning vertical axis basket 50%
aqueous ethanol increasing stepwise over a 5-minute period at 10% increments to 95% ethanol, those ethanolic wash solutions being discharged from the vertical axis basket centrifuge and transferred to the SOP-liquid receiving tank. This incremental washing results in SOP weight reduction due to dehydration (see DRAWINGS: Table 9). After the 95% ethanol step has been accomplished, the centrifuge basket is spun at 500 X g (or more) for a further 5 minutes, then stopped and the lightly coloured (yellow brown), ethanol-dehydrated SOP is peeled from the walls of the centrifuge's vertical axis basket.
Page 11 of 11 STEP 7B: The angular velocity of the vertical axis basket centrifuge is set such that the spinning vertical axis basket provides a centripetal force equivalent to or greater than 500 X g, resulting in the incoming SOP from the SOP-forming tank being packed against the vertical axis basket filter and clear liquid with its solutes being dispelled through the filter and transferred from the vertical axis basket centrifuge to a SOP-liquid receiving tank. When the vertical axis basket centrifuge has accumulated a full load of SOP, the feed valve from the SOP-forming tank is closed to stop transfer of any additional SOP suspension into the centrifuge's vertical axis basket, and rotation of the vertical axis basket is stopped. The discharge valve permitting clear liquid to pass from the vertical axis basket centrifuge to the SOP-liquid receiving tank is closed, and to the centrifuge's vertical axis basket is added a known volume of water and ethanol (1:1 v/v) in admixture with 3% (w/v) hydrogen peroxide in order to re-wet and re-suspend the SOP. The vertical axis basket centrifuge is activated briefly to provide a low centripetal or agitational force; then, the vertical axis basket's rotation is brought to a stop and held static for 15 minutes. Next, the vertical axis basket centrifuge is activated to provide a centripetal force of 500 X g (or more), the centrifuge discharge valve to the SOP-liquid receiving tank is opened, and SOP in the vertical axis basket is washed briefly by injecting into the spinning vertical axis basket 50% aqueous ethanol increasing stepwise over a 5-minute period at 10% increments to 95% ethanol, those ethanolic wash solutions being discharged from the vertical axis basket centrifuge and transferred to the SOP-liquid receiving tank. After the 95% ethanol step has been reached, the centrifuge basket is spun to provide 500 X g (or more) for a further 5 minutes, then stopped and the bleached (white), ethanol-dehydrated SOP peeled from the walls of the centrifuge basket. A variation on STEP 7B involves mixing of ethanol-dehydrated SOP
as provided from STEP 7A with 3% (w/v) hydrogen peroxide at ambient temperature in order to produce a clear solution of oligosaccharides and polysaccharides which are rapidly bleached. Said clear solution is then combined with an equal volume of ethanol to produce a SOP suspension. In the vertical axis basket centrifuge, SOP is separated and dehydrated as described above.
STEP 8: The dehydrated SOP is peeled from the vertical axis basket and transferred to a SOP
packaging and storage facility.
In addition to the preceding eight steps of the SOP process, solvent recovery is part of the process. The solution in the SOP-liquid receiving tank is transferred to a unit where ethanol is distilled. After distillation, a solution of aqueous alkali remains as the residue. Distilled ethanol is returned to the ethanol tank, and the aqueous alkali is transferred by either pumping or gravity flow to the alkali tank. The solution in the alkali tank is titrated and its NaOH
concentration adjusted for Page 12 of 12 use in STEP 2 and/or STEP 4 or for pulping of the residual chips in the digester after completion of STEP 5. Following multiple recycling of the alkaline solution in support of STEP 2 and/or STEP 4, there accumulates within that solution an increasing content of high-value wood extractives, such as xylitol from birch wood, which can be recovered and sold commercially.
Woods from tree species of worldwide distribution were investigated (DRAWINGS:
Figure 2, Table 10), and SOP yields varied by species. Various modifications can be made to the SOP
process in order to optimize it to the wood without departing from the scope of the present invention. The size of wood particle introduced into the batch digester can vary from large chip to ground-wood fibre, the latter clearly giving the better yield (see DRAWINGS:
Table 10); the alkalinity can be changed from 2.5 M NaOH to either higher or lower molarity (see DRAWINGS:
Figure 3, Tables 2, 6 and 7); KOH or LiOH rather than NaOH solution can be used for extraction of oligosaccharides and polysaccharides (see DRAWINGS: Table 7); the extraction temperature can be higher or lower than 50 C (see DRAWINGS: Figure 3); the time of extraction within the batch digester can be longer or shorter than 1 hour (see DRAWINGS: Tables 1 and 4);
the number of digester extractions used to obtain oligosaccharides and polysaccharides can be reduced to only one or increased to two or more (see DRAWINGS: Table 4); methanol, 2-propanol or n-butanol rather than ethanol can be used to yield SOP (see DRAWINGS: Table 5); separation of SOP from liquid can be accomplished by means of a moving wire screen as used in the paper-making process, or by vacuum or gravity filtration through a cellulose-based filter; the hydrogen peroxide concentration, time and temperature used in bleaching can be modified.
Literature cited Adams, G.A. and Castagne, A.E. 1951. Canadian Journal of Chemistry 29:109.
Aspinall, G. O. 1970. Polysaccharides. Pergamon Press, Oxford.
Hunter, D. 1947. Papermaking. Dover Publications, New York.
Neilson, M.J. and Richards, G. N. 1978. Journal of the Science of Food and Agriculture 29:513.
Niemela, K. 1990. Annales Academiae Scientiarum Fennicae, Series A, II.
Chemica 229.
Norris, F.W. and Preece, I. A. 1930. Biochemistry Journal 24:59.
Patt, R. and Kordsachia, O. 1986. Das Papier 40 (10A):V1.
Sands, L. and Gary, W. Y. 1933. Journal ofBiological Chemistry 101:573.
Wilkie, K.C.B. 1985. pp 1-37, in Biochemistry of Plant Cell Walls, edited by C.T. Brett and J. R.
Hillman, Cambridge U. Press.
Page 13 of 13
The process claimed herein produces dehydrated solid oligosaccharides and polysaccharides (SOP) from chemical substances resident within raw wood particles. Any chemical or semi-chemical process of wood pulping involving use of alkaline liquor in the digester is compatible with the SOP
process. As indicated in the DRAWINGS (Fig. 1), the SOP process includes capability for washing and bleaching of SOP and recovery of the liquids used in the process. In addition, once SOP has been produced by the process, it can be readily transformed into a clear solution of oligosaccharides and polysaccharides merely by mixing dehydrated SOP with water.
The novelty of the SOP process goes beyond linking together a series of existing technologies in the correct sequence needed to provide large quantities of SOP
for use in various commercial production streams. The black liquor issuing from the digester after pulping contains not only sulfonated lignin derivatives but also sulfonated and otherwise chemically modified compounds derived from the hemicellulose fraction of wood (Niemela 1990 - full references are given in the Literature Cited section before the Claims). By removing soluble and/or miscible oligosaccharides and polysaccharides at the beginning of the pulping process, a significant fraction of wood substance is prevented from contributing to the black liquor stream.
SOP, unbleached or bleached, is the deliverable from the SOP process.
Potential end uses of SOP are multi-faceted but not the subject of this Specification. SOP may well be found directly useful for production of novel kinds of paper (e.g., water-soluble paper) and is expected to find application as a paper additive (i.e., as a sizing). SOP as an intermediate product will, upon further processing, likely find use in applications such as food (digestive fiber), chewing and other gums, bulking agent in well-drilling, ethanol, energy production, and many other end products.
Background and Prior Art. The first writing/drawing paper was made by the Egyptians from the lowermost stem parts of papyrus, a sedge that grows up to 5 m in height, using a semi-pulping process involving stem slicing, pounding, cross-lapping and drying (Hunter 1947). Thus, the word "paper" is derived from the Greek and Latin words papuros and papyrus, respectively. The production of paper from papyrus exploited the natural ability of cellulose present in cell walls of all plant fibrous elements to bond together even when the plant tissue's adjoining fibres remain intact, but "true' paper is made from plant tissues that have been reduced to their individual fibres (i.e., fully pulped) and then re-constituted from a fibrous pulp suspension. True paper was being produced manually in China as early as the 2nd century BC, by pounding wetted cloth rags and/or Page 3 of 3 bark to pulp, using a screen to lift the pulp out of the pulp vat and produce a wet layer of pulp, followed by pressing absorbed moisture out and then hanging and drying that `sheet' into paper.
Many centuries of paper-making followed (Hunter 1947).
Wood as it occurs in logs is a relatively hard bulky and inflexible material;
therefore, at the outset of paper-making, wood was likely given no consideration as a material for manually pounding into pulp. Use of wood for paper-making evidently was first suggested in 1719 by Rene Antoine Ferchault de Reaumur following his observations of papery nests created by American and Canadian wood wasps. Nevertheless, it was not until 1765 that Jacob Christian Schaffer made papers from pulp of beech, willow, aspen, mulberry, spruce and other woods, each paper being produced from wood pulp in admixture with rag fibres. Schaffer also noted that wood treated with a lime paste required less time and energy to beat into pulp than untreated wood, and this evidently was the first step toward chemical pulping of wood.
The first paper originating entirely from wood pulp appears to have been a single page made of elm-wood fibres and produced in 1786 by Leorier Delisle (in a book authored by Charles Michel de Villette). In 1798 Nicolas-Louis Robert constructed a moving screen belt capable of receiving a continuous flow of pulp suspension and delivering an unbroken sheet of wet paper to a pair of squeeze rolls where most of the residual liquid was removed from the adjoining fibres, and that innovation set the stage for mass production of paper hence the demand for larger quantities of pulp than could be produced manually. In 1800 the Great Seal Patent office, London, granted Matthias Koops a patent "...for a method of manufacturing paper from straw, hay, thistles, waste, and ruse of hemp and flax, and different kinds of wood and bark." In 1840 Friedrich Gottlob Keller secured a German patent for grinding logs against a millstone and, in 1867, ground-wood pulp was being produced in Massachusetts in order to make newsprint solely from wood fibres.
Newsprint as produced from chemically untreated ground wood was dull, darkened quickly and was not very strong, and the desire to produce stronger, brighter paper from wood led to investigations into chemical pulping. The first chemical pulping of wood to operate on the industrial scale was the soda process, so-named because it uses sodium hydroxide (NaOH) as the cooking agent. The soda process was developed in 1851 by Hugh Burgess and Charles Watt in England, and they secured a USA patent for the process in 1854. Alkaline sulfite pulping was patented in 1867 by Benjamin Tilghman in the USA, and Kraft pulping was patented in 1884 by Carl Dahl of Germany.
Many variations on those chemical pulping processes have subsequently been described, and innumerable patents exist in relation to their modifications. One variation presently invoking Page 4 of 4 considerable interest is known as ASAM pulping (alkaline sulfite with anthraquinone and methanol), described by Patt and Kordsachia (1986). The SOP process is compatible with digesters using soda, alkaline sulfite, Kraft or ASAM chemical, semi-chemical or chemi-mechanical pulping.
All chemical and related pulping processes are concerned with one or more direct or ancillary aspects of the treatment of wood particles with harsh chemicals at high temperature and pressure for extended periods, the aim being to break the chemical bonds between lignin, hemicelluloses and cellulose in order that the individual woody elements, usually referred to as `fibres', can exist independently and generate a useable pulp. Because chemical methods of pulping require that the wood particles be treated for several hours above atmospheric pressure at a temperature above the boiling point (approximately 100 C) of the cooking liquor, a pressure cooker known as a`digester' is used and is the starting point of the pulping process.
Under the harsh conditions associated with cooking wood particles within a digester, not only lignins but a variety of compounds collectively but non-specifically referred to as `hemicelluloses' are hydrolyzed within the wood cell walls and released into the cooking liquor. In recent years, wood hemicelluloses have been identified as an important material for manufacture of ethanol, and various patents related to ethanol production from sugars derived from hemicelluloses have been filed.
However, to the best of my knowledge none of those patents has addressed development of an industrial process such as described herein, for obtaining from a relatively mild alkaline solution applied to wood particles within a pulp-mill digester oligosaccharides and polysaccharides before those substances become part of the waste black liquor stream.
The use of an aliphatic alcohol to coagulate or "precipitate" polysaccharides in an alkaline solution gained acceptance as a routine scientific method, of common knowledge in the public domain, early in the 20th century (e.g., Norris and Preece 1930; Sands and Gary 1933; Adams and Castagne 1951). Following upon that scientific advance, several patents were nevertheless awarded specifically in relation to use of an aliphatic alcohol, such as ethanol, to precipitate "hemicelluloses"
from alkaline extracts of plant tissues. For example, US patent 3935022 for the manufacture of viscose products claimed "a process for removing hemicelluloses from hemicellulose-containing alkali solution consisting essentially of adding to said alkali solution a sufficient amount of a solvent consisting essentially of ethanol to precipitate hemicellulose from said alkali solution..." Similarly, US patent 7101996 claimed "a process for the separation of purified hemicelluloses from insoluble cellulose and cellulose-hemicellulose complexes in caustic liquor from solubilizing fiber with alkali comprising the steps of adding alcohol to the caustic liquor to precipitate the hemicelluloses..."
Page 5 of 5 However, the supposed inventions underlying those claims were already in the public domain.
Moreover, the details of practicable industrial processes were not specified as such in those patents.
In addition, there has been a tendency in the patent literature for the term `hemicellulose' to be used unclearly, although the meaning of the term has been more rigorously interpreted (Aspinall 1970, Wilkie 1985). As noted by Wilkie (1985), "Confusion and uncertainty is caused when terms are used that are ill-defined or, as in the case of hemicelluloses, when terms have considerable, and unrecognized, variability in their defmition."
The Claims made herewith embody a practicable industrial process for obtaining a mixture of solid oligosaccharides and polysaccharides (SOP) in major quantity from raw wood particles during pulping involving the use of an alkaline solution in the digester. For brevity, it is referred to as the 'SOP process'. The embodiments of the SOP process require that a distinction be made between the natural hemicelluloses of wood and the oligosaccharides and polysaccharides obtained by the SOP process. Aqueous alkaline treatment of cell walls of woody elements not only hydrolyzes into smaller molecules those substances referred to as hemicelluloses but also saponifies the natural esters (e.g., acetyl or diferulyl groups) which are natural to the hemicelluloses. In other words, alkali extraction changes the true or `native' hemicelluloses of wood into de-esterified polysaccharides and shorter oligosaccharides differing in both chemical properties and chain length from those occurring naturally in wood (Neilson and Richards 1978). One way to understand the distinction is to consider the solubility of hemicelluloses vis-a-vis solid oligosaccharides and polysaccharides (SOP) obtained by the SOP process. In general native hemicelluloses will produce a cloudy suspension rather than a clear solution when mixed with cool or lukewarm water. SOP, on the other hand, upon mixing with water at sub-ambient or higher temperature, quickly provides a clear solution of oligosaccharides and polysaccharides. In other words, the colligative properties of SOP are different from those of native hemicelluloses.
In developing this invention referred to as the SOP process, a variety of woody plant species - 39 tree species and 2 additional species (viz., bamboo and cotton) - growing worldwide was investigated (Fig. 2). Based on that research, it can be concluded that many, possibly all, woods will yield some amount of SOP when subjected to the SOP process. However, as shown in Figure 2, the yield clearly varies among species, with Magnoliophyta in general providing more SOP than Coniferophyta. Of the species investigated, bamboo stems yielded the most SOP, raw fibres of the cotton boll the least (Fig. 2).
Page 6 of 6 The chemistry of SOP from Betula populifolia wood was investigated in some depth, by dialysis followed by sulfuric acid hydrolysis of the SOP followed by barium carbonate neutralization, drying, trimethylsilylation and analysis by combined gas chromatography - mass spectroscopy (GC/MS). Dialysis through cellulose acetate of different molecular-weight cutoffs established that B. populifolia SOP comprises short-chain oligosaccharides as well as polysaccharides. GC/MS of hydrolyzed trimethylsilylated SOP revealed that both the oligosaccharides and polysaccharides contain equal amounts of D-xylose and a second equally abundant monosaccharide the precise identity of which could not be unequivocally established.
Preliminary investigations indicate that those two compounds characterize Magnoliophyta SOP in general; however, considerable research remains to be done on the chemical properties of SOP.
The SOP process embodies the requirement for sequential, correctly ordered, precise and economically efficient use of a number of existing technologies, viz., 1) conversion of logs into particles of wood, 2) conveyance of a known weight of those wood particles into the cooking chamber of a pulp-mill digester, 3) preparation of a defmed alkaline solution of known molarity, 4) conveyance of a known volume of defined alkaline solution of known molarity to the wood particles within the cooking chamber, 5) warming of the alkaline solution within the cooking chamber to a known temperature and maintaining the digester's cooking chamber at that temperature for a known time, 6) removing a known volume of the alkaline solution from the cooking chamber and transferring that volume to a tank capable of stirring the alkaline solution at ambient temperature, 7) stirring the known volume of alkaline solution in the tank at ambient temperature and, while stirring, adding to the volume of alkaline solution an equal volume of an aliphatic alcohol at ambient temperature in order to create a suspension of SOP, 8) transferring the SOP
suspension in a regulated way from the tank to a mechanical device (e.g., a filter-lined centrifuge, a paper-making wire, a vacuum-filtration system, or a gravity-feed filtration system) capable of separating solids from liquids followed by washing of the solids, 9) repeating steps 3 - 8 a second time to achieve a higher SOP yield, 10) if desired, bleaching SOP with hydrogen peroxide in a defmed solution of known concentration at known temperature for a known time, 11) whether or not SOP is bleached as per step 10, dehydrating SOP using either aliphatic alcohol or air drying, 12) distilling the liquid removed from the SOP suspension in order to reuse the aliphatic alcohol and alkaline solutions, 13) further processing of the SOP including treatment with a known volume of water per unit mass of solid in order to produce clear solutions, 14) packaging and/or sale of the SOP, 15) pulping the residue of wood particles remaining in the digester following completion of step 9.
Page 7 of 7 List of Figures and Tables.
Figure 1. Sequential steps of the SOP process when using 2.5 M NaOH, ethanol and a vertical axis basket continuous centrifuge. Chemical recovery/recycling operations follow step 8.
Figure 2. Percentage yield of SOP from dry, raw wood particles of 36 Magnoliophyta and 2 Coniferophyta species; bars indicate standard deviations for 3 replicate investigations.
Figure 3. Percentage yield of SOP from dry, raw wood as a function of temperature and NaOH
molarity, based on Betula populifolia wood particles.
Table 1. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles for different time periods with 1 M NaOH at 25 C;
standard deviations (s.d.) are for 3 replicate investigations.
Table 2. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles for 1 hour at 50 C;, comparing NaOH molarities;
standard deviations (s.d.) are for 3 replicate investigations.
Table 3. Dehydrated SOP yields (% of dry, raw wood weight) after extracting different sizes of dry, raw Betula populifolia wood particles once or twice for different time periods with 2.5 M NaOH at 50 C; standard deviations (s.d.) are for 3 replicate investigations.
Table 4. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles once or twice for different time periods with 2.5 M
NaOH at 50 C;
standard deviations (s.d.) are for 3 replicate investigations.
Table 5. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with 2.5 M NaOH for one hour at 50 C; and adding an equal volume of an aliphatic alcohol to generate a SOP suspension; standard deviations (s.d.) are for 3 replicate investigations.
Table 6. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with 1.0 M NaOH or 2.5 M NaOH at 50 C and adding the indicated volume of ethanol to generate a SOP suspension; standard deviations (s.d.) are for 3 replicate investigations.
Table 7. Dehydrated SOP yields (% of dry, raw wood weight) after extracting dry, raw Betula populifolia wood particles with four kinds of alkali at 1.0 M or 2.5 M
concentrations for 1 hour at 50 C; standard deviations (s.d.) are based on 3 replicate investigations.
Page 8 of 8 Table 8. Yields (% of weight of dry, raw Betula populifolia wood particles) of unbleached and bleached (3% H202 for 10 minutes at ambient temperature) dehydrated SOP
retained by a cellulosic filter following centrifugation at 500 X g; standard deviations (s.d.) are for 3 replicate investigations.
Table 9. Weight change of dehydrated SOP (% of the weight of dehydrated Betula populifolia raw SOP based on the yield provided using 50% ethanol) in relation to incremental increases in ethanol concentration during centrifugation, always in the presence of 2.5 M NaOH;
standard deviations (s.d.) are for 3 replicate investigations.
Table 10. Bleached (3% H202 for 10 minutes at ambient temperature) and unbleached dehydrated SOP yields (% of weight of dry, raw wood particles) from woods of several tree species; standard deviations (s.d.) are for 3 replicate investigations.
Page 9 of 9 An Example of Use Based on Wood of Grey Birch Figure 1 indicates the stepwise progression of the SOP process using 2.5 M
NaOH at 50 C in the digester, ethanol in the SOP-forming tank, and a vertical axis basket industrial centrifuge to separate, wash and bleach SOP. These conditions were identified as optimal for Betula populifolia (grey birch) wood particles, based on data displayed in the DRAWINGS (Fig. 3, Tables 1-10). The process shown in Figure 1 is explained as follows:
STEP 1: A pulp-mill batch digester is loaded with clean debarked particles of raw wood. The particles may be the size of chips, but a higher yield of SOP will be obtained from smaller particles and the highest yield from ground-wood fibres or sawdust (see DRAWINGS: Table 3).
STEP 2: The digester is filled with 2.5 M NaOH (4 litres or more of NaOH
solution per kilogram of dry wood). The digester's internal temperature is raised to 50 C and held for one hour, allowing the extraction of soluble and miscible substances from the wood particles to proceed under static conditions. As shown in DRAWINGS (Fig. 3), SOP yield would be higher at temperatures above 50 C.
STEP 3: The `1-h 50 C extract' arising from STEP 2 is transferred from the digester into a SOP-forming tank containing a stiurer and maintained under ambient conditions. It was determined by investigation of wood particles tightly packed into a vertical column (simulating a digester) that, following STEP 2, transfer of the 1-h 50 C extract from the digester will proceed by either gravity flow or upward displacement.
STEP 4: In order to increase the yield of SOP, immediately following the STEP
3 transfer of the 1-h 50 C extract to the SOP-forming tank, to the wood particle residue remaining in the digester is added a second volume of 2.5 M NaOH (see DRAWINGS: Table 4). Four litres of NaOH solution per kilogram of dry wood was found to be the optimal ratio. The digester internal temperature is raised to 50 C and held for one hour, allowing the extraction of soluble and miscible substances from the wood particles to proceed under static conditions.
STEP 5: The `2-h 50 C extract' arising from STEP 4 is transferred from the digester into either the same SOP-forming tank containing the 1-h 50 C extract or a second identical SOP-forming tank. It was determined by investigation of wood particles tightly packed into a vertical column (simulating a digester) that, following STEP 4, transfer of the 2-h 50 C extract from the digester will proceed by either gravity flow or upward displacement. Upon completing the transfer of the 2-h 50 C extract from the digester to a SOP-forming tank, if the wood particle residue in the digester constitutes wood chips, pulping follows by addition of the white liquor normally used in the chip-pulping Page 10 of 10 process. If the wood particles loaded into the digester is ground wood or sawdust, depending on the intended end use it may be considered that no additional digester pulping is needed and that the fibres can be mechanically separated (not shown in Fig. 1) and processed for their end purpose.
STEP 6: To the volume of 1-h 50 C extract and/or 2-h 50 C extract in the SOP-forming tank is added an equivalent volume of ethanol from the ethanol tank (see DRAWINGS:
Tables 5 and 6).
The stirrer in the SOP-forming tank is activated for one minute to vigorously mix the ethanol and 1-h 50 C extract and/or 2-h 50 C extract. The mixture is then permitted to sit for at least one hour under ambient, static conditions whereupon solid oligosaccharide and polysaccharides (SOP) precipitate. The resulting suspension in the SOP-forming tank is then continuously stirred, and while being actively stirred the SOP suspension is transferred from the SOP-forming tank by either pumping or gravity flow to an actively spinning continuous vertical axis basket centrifuge, said centrifuge basket being fitted with a cellulose-based filter.
STEP 7: At this step, the option exists to generate washed unbleached SOP via STEP 7A or washed bleached SOP via STEP 7B. In general, the yield of bleached dehydrated SOP is lower than that of unbleached SOP (see DRAWINGS: Table 8, Table 10).
STEP 7A: The angular velocity of the vertical axis basket centrifuge is set such that the spinning vertical axis basket provides a centripetal force equivalent to 500 X g. A
higher g force is acceptable, but 500 X g was determined to be satisfactory. Centrifugation results in the incoming SOP from the SOP-forming tank being packed against the vertical axis basket filter while the suspension's clear liquid with its solutes is dispelled through the filter and transferred to a SOP-liquid receiving tank. When the vertical axis basket centrifuge has accumulated a full load of SOP, the feed valve from the SOP-forming tank is closed to stop transfer of any additional SOP slurry into the centrifuge basket. With the centrifuge vertical axis basket still spinning to provide 500 X g (or more), SOP in the basket is washed briefly by injecting into the spinning vertical axis basket 50%
aqueous ethanol increasing stepwise over a 5-minute period at 10% increments to 95% ethanol, those ethanolic wash solutions being discharged from the vertical axis basket centrifuge and transferred to the SOP-liquid receiving tank. This incremental washing results in SOP weight reduction due to dehydration (see DRAWINGS: Table 9). After the 95% ethanol step has been accomplished, the centrifuge basket is spun at 500 X g (or more) for a further 5 minutes, then stopped and the lightly coloured (yellow brown), ethanol-dehydrated SOP is peeled from the walls of the centrifuge's vertical axis basket.
Page 11 of 11 STEP 7B: The angular velocity of the vertical axis basket centrifuge is set such that the spinning vertical axis basket provides a centripetal force equivalent to or greater than 500 X g, resulting in the incoming SOP from the SOP-forming tank being packed against the vertical axis basket filter and clear liquid with its solutes being dispelled through the filter and transferred from the vertical axis basket centrifuge to a SOP-liquid receiving tank. When the vertical axis basket centrifuge has accumulated a full load of SOP, the feed valve from the SOP-forming tank is closed to stop transfer of any additional SOP suspension into the centrifuge's vertical axis basket, and rotation of the vertical axis basket is stopped. The discharge valve permitting clear liquid to pass from the vertical axis basket centrifuge to the SOP-liquid receiving tank is closed, and to the centrifuge's vertical axis basket is added a known volume of water and ethanol (1:1 v/v) in admixture with 3% (w/v) hydrogen peroxide in order to re-wet and re-suspend the SOP. The vertical axis basket centrifuge is activated briefly to provide a low centripetal or agitational force; then, the vertical axis basket's rotation is brought to a stop and held static for 15 minutes. Next, the vertical axis basket centrifuge is activated to provide a centripetal force of 500 X g (or more), the centrifuge discharge valve to the SOP-liquid receiving tank is opened, and SOP in the vertical axis basket is washed briefly by injecting into the spinning vertical axis basket 50% aqueous ethanol increasing stepwise over a 5-minute period at 10% increments to 95% ethanol, those ethanolic wash solutions being discharged from the vertical axis basket centrifuge and transferred to the SOP-liquid receiving tank. After the 95% ethanol step has been reached, the centrifuge basket is spun to provide 500 X g (or more) for a further 5 minutes, then stopped and the bleached (white), ethanol-dehydrated SOP peeled from the walls of the centrifuge basket. A variation on STEP 7B involves mixing of ethanol-dehydrated SOP
as provided from STEP 7A with 3% (w/v) hydrogen peroxide at ambient temperature in order to produce a clear solution of oligosaccharides and polysaccharides which are rapidly bleached. Said clear solution is then combined with an equal volume of ethanol to produce a SOP suspension. In the vertical axis basket centrifuge, SOP is separated and dehydrated as described above.
STEP 8: The dehydrated SOP is peeled from the vertical axis basket and transferred to a SOP
packaging and storage facility.
In addition to the preceding eight steps of the SOP process, solvent recovery is part of the process. The solution in the SOP-liquid receiving tank is transferred to a unit where ethanol is distilled. After distillation, a solution of aqueous alkali remains as the residue. Distilled ethanol is returned to the ethanol tank, and the aqueous alkali is transferred by either pumping or gravity flow to the alkali tank. The solution in the alkali tank is titrated and its NaOH
concentration adjusted for Page 12 of 12 use in STEP 2 and/or STEP 4 or for pulping of the residual chips in the digester after completion of STEP 5. Following multiple recycling of the alkaline solution in support of STEP 2 and/or STEP 4, there accumulates within that solution an increasing content of high-value wood extractives, such as xylitol from birch wood, which can be recovered and sold commercially.
Woods from tree species of worldwide distribution were investigated (DRAWINGS:
Figure 2, Table 10), and SOP yields varied by species. Various modifications can be made to the SOP
process in order to optimize it to the wood without departing from the scope of the present invention. The size of wood particle introduced into the batch digester can vary from large chip to ground-wood fibre, the latter clearly giving the better yield (see DRAWINGS:
Table 10); the alkalinity can be changed from 2.5 M NaOH to either higher or lower molarity (see DRAWINGS:
Figure 3, Tables 2, 6 and 7); KOH or LiOH rather than NaOH solution can be used for extraction of oligosaccharides and polysaccharides (see DRAWINGS: Table 7); the extraction temperature can be higher or lower than 50 C (see DRAWINGS: Figure 3); the time of extraction within the batch digester can be longer or shorter than 1 hour (see DRAWINGS: Tables 1 and 4);
the number of digester extractions used to obtain oligosaccharides and polysaccharides can be reduced to only one or increased to two or more (see DRAWINGS: Table 4); methanol, 2-propanol or n-butanol rather than ethanol can be used to yield SOP (see DRAWINGS: Table 5); separation of SOP from liquid can be accomplished by means of a moving wire screen as used in the paper-making process, or by vacuum or gravity filtration through a cellulose-based filter; the hydrogen peroxide concentration, time and temperature used in bleaching can be modified.
Literature cited Adams, G.A. and Castagne, A.E. 1951. Canadian Journal of Chemistry 29:109.
Aspinall, G. O. 1970. Polysaccharides. Pergamon Press, Oxford.
Hunter, D. 1947. Papermaking. Dover Publications, New York.
Neilson, M.J. and Richards, G. N. 1978. Journal of the Science of Food and Agriculture 29:513.
Niemela, K. 1990. Annales Academiae Scientiarum Fennicae, Series A, II.
Chemica 229.
Norris, F.W. and Preece, I. A. 1930. Biochemistry Journal 24:59.
Patt, R. and Kordsachia, O. 1986. Das Papier 40 (10A):V1.
Sands, L. and Gary, W. Y. 1933. Journal ofBiological Chemistry 101:573.
Wilkie, K.C.B. 1985. pp 1-37, in Biochemistry of Plant Cell Walls, edited by C.T. Brett and J. R.
Hillman, Cambridge U. Press.
Page 13 of 13
Claims (61)
1. A process for producing from raw wood during soda, kraft, alkaline sulfite or any other industry of chemical or semi-chemical alkaline-pulping a fluid suspension of Solid Oligosaccharides and Polysaccharides, referred to as a fluid SOP suspension, comprising the steps of:
(a) adding to a pulp-mill digester a known mass of raw wood particles;
(b) adding to said raw wood particles in said digester an alkaline extracting solution;
(c) maintaining said raw wood particles of step (a) immersed with said alkaline extracting solution of step (b) for a defined time at approximately ambient atmospheric pressure and a warm temperature;
(d) removing said alkaline extracting solution of step (b) from said digester while maintaining within said digester said particles of wood introduced during step (a), concomitantly transferring said alkaline extracting solution of step (b) to a SOP-forming tank having a mechanism for mixing liquids after they have been placed within it;
(e) adding to the SOP-forming tank a volume of aliphatic alcohol equaling that of the volume of alkaline extracting solution transferred to said SOP-forming tank in step (d), concomitantly mixing that added alcohol thoroughly with said alkaline extracting solution of step (d) for one minute to produce said fluid SOP suspension.
(a) adding to a pulp-mill digester a known mass of raw wood particles;
(b) adding to said raw wood particles in said digester an alkaline extracting solution;
(c) maintaining said raw wood particles of step (a) immersed with said alkaline extracting solution of step (b) for a defined time at approximately ambient atmospheric pressure and a warm temperature;
(d) removing said alkaline extracting solution of step (b) from said digester while maintaining within said digester said particles of wood introduced during step (a), concomitantly transferring said alkaline extracting solution of step (b) to a SOP-forming tank having a mechanism for mixing liquids after they have been placed within it;
(e) adding to the SOP-forming tank a volume of aliphatic alcohol equaling that of the volume of alkaline extracting solution transferred to said SOP-forming tank in step (d), concomitantly mixing that added alcohol thoroughly with said alkaline extracting solution of step (d) for one minute to produce said fluid SOP suspension.
2. The process of Claim I wherein said raw wood particles are chips either pre-steamed or unsteamed and up to 10 mm in thickness and 50 mm in length from the wood of any plant species.
3. The process of Claim 1 wherein said raw wood particles are ground-wood fibres either pre-steamed or unsteamed from the wood of any plant species.
4. The process of Claim 1 wherein said raw wood particles are sawdust, either pre-steamed or unsteamed, from the wood of any plant species.
5. The process of Claim 1 wherein said digester is a pulp-mill batch digester.
6. The process of Claim 1 wherein said digester is a pulp-mill continuous digester operated in discontinuous mode.
7. The process of Claim 1 wherein said digester is any container capable of being loaded with and subsequently unloaded of wood particles and alkaline solution.
8. The process of Claim 1 wherein said alkaline extracting solution preferably consists of a known molarity of sodium hydroxide in water.
9. The process of Claim 1 wherein said alkaline extracting solution consists of a known molarity of potassium hydroxide in water.
10. The process of Claim 1 wherein said alkaline extracting solution consists of a known molarity of lithium hydroxide in water.
11. The process of Claim 1 wherein the volume in litres of said alkaline extracting solution is not less and may be more than four times the mass in kilograms of raw wood put into the digester.
12. The process of Claim 1 wherein said defined time of immersion of raw wood particles in alkaline extracting solution at ambient atmospheric pressure and warm temperature is not less than minutes and not more than 96 hours.
13. The process of Claim 1 wherein said warm temperature of the alkaline extracting solution in the digester is not less than 0°C or more than 100 °C.
14. The process of Claim 1 wherein said SOP-forming tank is a container compatible with said alkaline extracting solution and said aliphatic alcohol and having a mechanism to agitate those liquids and release from said SOP-forming tank said fluid SOP suspension.
15. The process of Claim 1 wherein the volume capacity of said SOP-forming tank is greater than twice the volume of said alkaline extracting solution transferred to it from said digester.
16. The process of Claim 1 wherein said aliphatic alcohol added to said alkaline extracting solution in said SOP-forming tank is preferably ethanol, otherwise known as ethyl alcohol, grain alcohol, hydroxyethane or ethyl hydrate.
17. The process of Claim 1 wherein said aliphatic alcohol added to said alkaline extracting solution in said SOP-forming tank is methanol, otherwise known as methyl alcohol, hydroxymethane, methyl hydrate, wood alcohol or carbinol.
18. The process of Claim 1 wherein said aliphatic alcohol added to said alkaline extracting solution in said SOP-forming tank is 2-propanol, otherwise known as isopropanol, isopropyl alcohol or propan-2-ol.
19. The process of Claim 1 wherein said aliphatic alcohol added to said alkaline extracting solution in said SOP-forming tank is n-butanol, otherwise known as normal butanol, butyl alcohol, butyric alcohol, propylcarbinol, 1-butanol, or butan-1-ol.
20. The process of Claim 1 wherein said aliphatic alcohol added to said alkaline extracting solution in said SOP-forming tank is any combination of ethanol, methanol, 2-propanol and n-butanol.
21. The process of Claim 1 wherein said mechanism for mixing liquids within said SOP-forming tank is sufficient to achieve thorough mixing of said aliphatic alcohol and said alkaline extracting solution.
22. The process of Claim 1 wherein the admixture of said aliphatic alcohol and said alkaline extracting solution in said SOP-forming tank is retained in said SOP-forming tank for not more than 48 hours.
23. The process of Claim 1 wherein steps (b), (c) and (d) of Claim 1 are repeated before said wood particles in said digester are charged with a stronger caustic solution and subjected to elevated pressure and a temperature above 100 °C in order to complete the pulping of said wood particles in said digester.
24. A process for separating Solid Oligosaccharides and Polysaccharides, referred to as SOP, produced in said SOP-forming tank from clear liquid associated with said fluid SOP suspension of Claim 1 and producing from said SOP a preparation of washed, dehydrated solid oligosaccharides and polysaccharides, referred to as dehydrated SOP, comprising the steps of:
(a) transferring said fluid SOP suspension produced in said SOP-forming tank of Claim 1 to a mechanical device capable of removing said clear liquid and retaining said SOP;
(b) washing said SOP of step (a) of Claim 24;
(c) dehydrating said SOP of step (a) and/or step (b) of Claim 24;
(d) transferring said clear liquids derived from said removing, said washing and said dehydrating of steps (a), (b) and (c), respectively, of Claim 24 to a SOP-liquid receiving container;
(e) recovering said washed and said dehydrated SOP of Claim 24.
(a) transferring said fluid SOP suspension produced in said SOP-forming tank of Claim 1 to a mechanical device capable of removing said clear liquid and retaining said SOP;
(b) washing said SOP of step (a) of Claim 24;
(c) dehydrating said SOP of step (a) and/or step (b) of Claim 24;
(d) transferring said clear liquids derived from said removing, said washing and said dehydrating of steps (a), (b) and (c), respectively, of Claim 24 to a SOP-liquid receiving container;
(e) recovering said washed and said dehydrated SOP of Claim 24.
25. The process of Claim 24 wherein said mechanical device is preferably a continuous vertical axis basket centrifuge performing the following steps:
(a) receiving as an insert and retaining against the interior wall of the vertical axis basket a removable filter that is permeable by said clear liquid and not permeable by said SOP;
(b) spinning the filter-lined vertical axis basket to provide a centripetal force;
(c) expelling said clear liquid associated with said fluid SOP suspension produced in said SOP-forming tank of Claim 1 from said filter of step (a) of Claim 25 to a centrifuge drain connected to a SOP-liquid receiving container while said vertical axis basket is actively spinning;
(d) washing said SOP within said vertical axis basket by injecting wash liquid into said vertical axis basket while it is actively spinning and expelling from said spinning vertical axis basket filter said wash liquid to a centrifuge drain connected to said SOP-liquid receiving container;
(e) dehydrating said SOP within said spinning vertical axis basket by injecting dehydration liquid into said spinning vertical axis basket, concomitantly expelling said dehydration liquid from said spinning vertical axis basket filter to said centrifuge drain connected to said SOP-liquid receiving container;
(f) peeling away said dehydrated SOP of Claim 24 from said vertical axis basket.
(a) receiving as an insert and retaining against the interior wall of the vertical axis basket a removable filter that is permeable by said clear liquid and not permeable by said SOP;
(b) spinning the filter-lined vertical axis basket to provide a centripetal force;
(c) expelling said clear liquid associated with said fluid SOP suspension produced in said SOP-forming tank of Claim 1 from said filter of step (a) of Claim 25 to a centrifuge drain connected to a SOP-liquid receiving container while said vertical axis basket is actively spinning;
(d) washing said SOP within said vertical axis basket by injecting wash liquid into said vertical axis basket while it is actively spinning and expelling from said spinning vertical axis basket filter said wash liquid to a centrifuge drain connected to said SOP-liquid receiving container;
(e) dehydrating said SOP within said spinning vertical axis basket by injecting dehydration liquid into said spinning vertical axis basket, concomitantly expelling said dehydration liquid from said spinning vertical axis basket filter to said centrifuge drain connected to said SOP-liquid receiving container;
(f) peeling away said dehydrated SOP of Claim 24 from said vertical axis basket.
26. The process of Claim 25 wherein said removable filter consists entirely or predominantly of material retaining said SOP of Claim 24 and chemically resistant to alkali, aliphatic alcohols and hydrogen peroxide.
27. The process of Claim 25 wherein said centripetal force of said vertical axis basket when spinning achieves not less than 500 X g. g being the nominal acceleration due to gravity on Earth at sea level and equaling approximately 9.8 m s -2.
28. The process of Claim 25 wherein said expelling of said clear liquid through said filter to said centrifuge drain is controlled by a valve that can be opened and closed to regulate transfer of said clear liquid from said continuous vertical axis basket centrifuge to said SOP-liquid receiving container of Claim 24.
29. The process of Claim 25 wherein said wash liquid is provided to said vertical axis basket while actively spinning as a gradient beginning with an aliphatic alcohol in water at 50% (v/v) and increasing gradually to 95% (v/v) or higher aliphatic alcohol in water.
30. The process of Claim 25 wherein said dehydration liquid is an aliphatic alcohol.
31. The processes of Claim 29 and Claim 30 wherein said aliphatic alcohol is preferably ethanol.
32. The processes of Claim 29 and Claim 30 wherein said aliphatic alcohol is methanol.
33. The processes of Claim 29 and Claim 30 wherein said aliphatic alcohol is 2-propanol.
34. The processes of Claim 29 and Claim 30 wherein said aliphatic alcohol is n-butanol.
35. The processes of Claim 29 and Claim 30 wherein said aliphatic alcohol may be any combination of ethanol, methanol, 2-propanol and n-butanol.
36. The process of Claim 24 wherein said mechanical device may be any filtration system capable of performing the following steps:
(a) receiving a removable filter that consists entirely or predominantly of material retaining said SOP of Claim 24 and chemically resistant to alkali, aliphatic alcohols and hydrogen peroxide;
(b) receiving and containing in the region above said filter of step (a) of Claim 36 some or all of the volume of said fluid SOP suspension produced in said SOP-forming tank of Claim 1;
(c) retaining said SOP of Claim 24 provided as said fluid SOP suspension produced in said SOP-forming tank of Claim 1 on the inlet side of said filter of step (a) of Claim 36;
(d) permitting said clear liquid of Claim 24 associated with said fluid SOP
suspension produced in said SOP-forming tank of Claim 1 to pass as filtrate through said filter of step (a) of Claim 36 to said SOP-liquid receiving container of Claim 24;
(e) washing said SOP of Claim 24 by providing wash liquid to said retained SOP
of step (c) of Claim 36 and allowing said wash liquid to pass as filtrate through said filter of step (a) of Claim 36 to said SOP-liquid receiving container of Claim 24;
(e) dehydrating said SOP of Claim 24 by providing dehydration liquid to the retained SOP above said filter of step (a) of Claim 36 and allowing said dehydration liquid to pass as filtrate through said filter to said SOP-liquid receiving container of Claim 24.
(a) receiving a removable filter that consists entirely or predominantly of material retaining said SOP of Claim 24 and chemically resistant to alkali, aliphatic alcohols and hydrogen peroxide;
(b) receiving and containing in the region above said filter of step (a) of Claim 36 some or all of the volume of said fluid SOP suspension produced in said SOP-forming tank of Claim 1;
(c) retaining said SOP of Claim 24 provided as said fluid SOP suspension produced in said SOP-forming tank of Claim 1 on the inlet side of said filter of step (a) of Claim 36;
(d) permitting said clear liquid of Claim 24 associated with said fluid SOP
suspension produced in said SOP-forming tank of Claim 1 to pass as filtrate through said filter of step (a) of Claim 36 to said SOP-liquid receiving container of Claim 24;
(e) washing said SOP of Claim 24 by providing wash liquid to said retained SOP
of step (c) of Claim 36 and allowing said wash liquid to pass as filtrate through said filter of step (a) of Claim 36 to said SOP-liquid receiving container of Claim 24;
(e) dehydrating said SOP of Claim 24 by providing dehydration liquid to the retained SOP above said filter of step (a) of Claim 36 and allowing said dehydration liquid to pass as filtrate through said filter to said SOP-liquid receiving container of Claim 24.
37. The process of Claim 36 wherein said filtration system is a gravity-flow filtration system.
38. The process of Claim 36 wherein said filtration system is a vacuum filtration system.
39. The process of Claim 36 wherein said filtration system is a continuous screen such as is commonly used in the initial stage of producing paper from pulp.
40. The process of Claim 36 wherein said wash liquid is provided as a gradient beginning with an aliphatic alcohol in water at 50% (v/v) and increasing gradually to 95% (v/v) or higher aliphatic alcohol in water.
41. The process of Claim 36 wherein said dehydration liquid is an aliphatic alcohol.
42. The processes of Claim 40 and Claim 41 wherein said aliphatic alcohol is preferably ethanol.
43. The processes of Claim 40 and Claim 41 wherein said aliphatic alcohol is methanol.
44. The processes of Claim 40 and Claim 41 wherein said aliphatic alcohol is 2-propanol.
45. The processes of Claim 40 and Claim 41 wherein said aliphatic alcohol is n-butanol.
46. The processes of Claim 40 and Claim 41 wherein said aliphatic alcohol may be any combination of ethanol, methanol, 2-propanol and n-butanol.
47. The process of Claim 24 wherein said dehydrated SOP is dehydrated by either air or oven drying, or both.
48. A process of producing dehydrated bleached SOP by washing said SOP of Claim 24 in hydrogen peroxide solution.
49. The process of Claim 48 wherein said hydrogen peroxide solution contains not less than 1% and not more than 10% (w/v) hydrogen peroxide in equal volumes of water and aliphatic alcohol.
50. The process of Claim 48 wherein said SOP of Claim 24 is immersed in said hydrogen peroxide solution at a temperature between 0°C and 100 °C for not less than five minutes and not more than 24 hours.
51. The process of Claim 48 wherein said SOP of Claim 24 is washed by said hydrogen peroxide solution within said continuous vertical axis basket centrifuge of Claim 25 using step (d) of Claim 25.
52. The processes of Claim 41, Claim 48 and Claim 51 wherein said SOP after washing with said hydrogen peroxide solution is dehydrated with said aliphatic alcohol of Claim 41 using said continuous vertical axis basket centrifuge process of Claim 25 using step (e) of Claim 25.
53. The process of Claim 48 wherein said SOP of Claim 24 is washed by said hydrogen peroxide solution within any mechanical device having said filtration system of Claim 36 using step (e) of Claim 36.
54. The processes of Claim 41, Claim 48 and Claim 53 wherein said SOP after washing with said hydrogen peroxide solution is dehydrated with said aliphatic alcohol of Claim 41 using said mechanical device having said filtration system of Claim 36 using step (f) of Claim 36.
55. The processes of Claims 48 to 54, inclusively, wherein said solution after washing and dehydrating is transferred to said SOP-liquid receiving container of Claim 24.
56. The process of Claim 48 wherein said bleached SOP after washing with said hydrogen peroxide solution is dehydrated by either air or oven drying, or both.
57. A process to produce a clear solution of water Miscible Oligosaccharides and Polysaccharides, referred to as MOP, from said SOP of Claim 24 or said bleached SOP of Claim 48, comprising the steps of:
(a) weighing a mass of said SOP;
(b) adding to the mass of said SOP a volume in litres of water equaling at least twice the mass in kilograms of said SOP;
(c) mixing together said SOP and said water at a temperature between 0°C and 100 °C until a clear solution is obtained.
(a) weighing a mass of said SOP;
(b) adding to the mass of said SOP a volume in litres of water equaling at least twice the mass in kilograms of said SOP;
(c) mixing together said SOP and said water at a temperature between 0°C and 100 °C until a clear solution is obtained.
58. A process to recover and re-use said aliphatic alcohol of Claims 1, 16-22, 26, 29-36, 40-46, 49, 52 and 54 involving transfer of alcohol-containing solutions to a distillation apparatus, distillation, condensation of the distillate and transfer of the alcohol distillate to an alcohol storage tank.
59. A process to recover and re-use said alkaline, washing, dehydration and hydrogen peroxide solutions of Claims 1, 24, 36 and 48 comprising the steps of:
(a) following said transfer of the alcohol distillate of Claim 58, transferring a known volume of the residual aqueous solution from said distillation apparatus of Claim 58 to an alkali storage tank;
(b) titration to determine the alkalinity of the solution in said alkali storage tank;
(c) addition of a known mass of alkali to said alkali storage tank followed by mixing to achieve a known molarity of alkaline solution in said alkali storage tank;
(d) transfer of the adjusted alkaline solution to said digester of Claim 1.
(a) following said transfer of the alcohol distillate of Claim 58, transferring a known volume of the residual aqueous solution from said distillation apparatus of Claim 58 to an alkali storage tank;
(b) titration to determine the alkalinity of the solution in said alkali storage tank;
(c) addition of a known mass of alkali to said alkali storage tank followed by mixing to achieve a known molarity of alkaline solution in said alkali storage tank;
(d) transfer of the adjusted alkaline solution to said digester of Claim 1.
60. A mixture of water soluble and/or miscible oligosaccharides and polysaccharides by the process of any one of the preceding claims.
61. An industrial installation specifically adapted for conducting the process of any one of Claims 1 to 59.
It will be apparent that modifications can be made to the described process without departing from the scope of the present invention.
Table 1.
Time (hours) % SOP s.d.
0.1 <0.1 0.0 1 7.6 0.2 27.5 0.4 3 8.3 0.4 4 7.6 0.3 Table 2.
NaOH
molarity % SOP s.d.
water only 0.3 0.0 1.0 4.6 0.1 2.5 14.7 0.3 5.0 11.2 0.6 10.0 13.2 0.3 Table 3.
Maximum particle surface area dimension (mm) (mm2/gram) % SOP s.d.
3.5 4160 16.0 0.5 130 1600 5.8 0.1 136 1280 5.8 0.2 176 1120 4.6 0.6 Table 4.
No. of times extracted Time (hours) % SOP s.d.
once 1 12.8 0.4 twice 1 and 1 17.3 0.3 twice 0.1 and 1 16.3 0.5 once 0.165 9.9 0.4 once 1.165 13.0 0.6 Table 5.
Aliphatic alcohol % SOP s.d.
ethanol 15.3 0.3 methanol 11.5 0.4 2-propanol 6.7 0.3 n-butanol 5.2 0.1 Table 6.
1.0 M NaOH 2.5 M NaOH
%(v/v) ethanol % SOP s.d. % SOP s.d.
50% 6.0 0.2 23.0 1.4 67% 7.4 0.3 21.5 1.1 Table 7.
Alkali % SOP (1.0 M) s.d. % SOP (2.5 M) s.d.
NaOH 4.3 0.3 15.9 0.7 KOH 4.9 0.0 13.8 0.5 LiOH 9.1 0.6 12.1 0.2 Table 8.
Suspension % SOP s.d.
SOP in 50% 14.9 0.8 ethanol, 2.5 M NaOH
SOP in 3% H2O2, 50% 8.8 1.0 ethanol, 2.5 M NaOH
Table 9.
% ethanol weight % s.d.
60 97.6 0.1 70 86.1 0.3 80 90.5 0.2 90 96.2 0.2 95 95.9 0.4 Table 10.
Tree species unbleached SOP (%) s.d. bleached SOP (%) s.d.
Betula populifolia 12.5 0.7 9.0 0.3 Betula alleghaniensis 10.4 0.0 9.4 0.3 Acer rubrum 7.2 0.6 6.4 0.1 Populus tremuloides 9.5 0.2 7.6 0.1
It will be apparent that modifications can be made to the described process without departing from the scope of the present invention.
Table 1.
Time (hours) % SOP s.d.
0.1 <0.1 0.0 1 7.6 0.2 27.5 0.4 3 8.3 0.4 4 7.6 0.3 Table 2.
NaOH
molarity % SOP s.d.
water only 0.3 0.0 1.0 4.6 0.1 2.5 14.7 0.3 5.0 11.2 0.6 10.0 13.2 0.3 Table 3.
Maximum particle surface area dimension (mm) (mm2/gram) % SOP s.d.
3.5 4160 16.0 0.5 130 1600 5.8 0.1 136 1280 5.8 0.2 176 1120 4.6 0.6 Table 4.
No. of times extracted Time (hours) % SOP s.d.
once 1 12.8 0.4 twice 1 and 1 17.3 0.3 twice 0.1 and 1 16.3 0.5 once 0.165 9.9 0.4 once 1.165 13.0 0.6 Table 5.
Aliphatic alcohol % SOP s.d.
ethanol 15.3 0.3 methanol 11.5 0.4 2-propanol 6.7 0.3 n-butanol 5.2 0.1 Table 6.
1.0 M NaOH 2.5 M NaOH
%(v/v) ethanol % SOP s.d. % SOP s.d.
50% 6.0 0.2 23.0 1.4 67% 7.4 0.3 21.5 1.1 Table 7.
Alkali % SOP (1.0 M) s.d. % SOP (2.5 M) s.d.
NaOH 4.3 0.3 15.9 0.7 KOH 4.9 0.0 13.8 0.5 LiOH 9.1 0.6 12.1 0.2 Table 8.
Suspension % SOP s.d.
SOP in 50% 14.9 0.8 ethanol, 2.5 M NaOH
SOP in 3% H2O2, 50% 8.8 1.0 ethanol, 2.5 M NaOH
Table 9.
% ethanol weight % s.d.
60 97.6 0.1 70 86.1 0.3 80 90.5 0.2 90 96.2 0.2 95 95.9 0.4 Table 10.
Tree species unbleached SOP (%) s.d. bleached SOP (%) s.d.
Betula populifolia 12.5 0.7 9.0 0.3 Betula alleghaniensis 10.4 0.0 9.4 0.3 Acer rubrum 7.2 0.6 6.4 0.1 Populus tremuloides 9.5 0.2 7.6 0.1
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9970038B2 (en) | 2009-08-06 | 2018-05-15 | Annikki Gmbh | Process for the production of carbohydrate cleavage products from a lingnocellulosic material |
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2007
- 2007-02-08 CA CA002578305A patent/CA2578305A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9970038B2 (en) | 2009-08-06 | 2018-05-15 | Annikki Gmbh | Process for the production of carbohydrate cleavage products from a lingnocellulosic material |
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