CN111868328A - Method and system for producing commodity pulp and product thereof - Google Patents

Abstract

Methods and systems for producing commodity pulp are provided that include treatment of pulp prior to drying of the pulp. In the production of commercial pulp, the pulp is treated with an anionic charged compound and an enzyme prior to drying of the pulp to improve pulp dewatering performance and efficiency. Also described are commodity pulp products containing the treating compounds.

Description

Method and system for producing commodity pulp and product thereof

The present application claims the benefit of prior U.S. provisional patent application No.62/643,224 filed 3/15/2018 and prior U.S. provisional patent application No.62/702,395 filed 7/24/2018 in accordance with 35 u.s.c. § 119(e), which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates to the production of commodity pulp. More specifically, methods and systems for producing commodity pulp are provided that include treating pulp with one or more anionic surfactants or compounds and one or more enzymes prior to drying the pulp.

Background

In the pulp manufacturing industry, cellulosic-containing feed materials have been defibered chemically, mechanically, or both, and then typically washed and at least partially dewatered after such operations. In pulping processes in which pulp is chemically treated, such as by chemical digestion, bleaching, or other chemical treatment, dewatering may be used to remove water and separate free chemicals from the fibers. Some pulp mills may be integrated with paper mills, wherein dewatering of the product pulp may be limited, so that the pulp or wet laid pulp may be pushed directly to the paper machine at the same production site. Other pulp mills produce commodity pulp in non-integrated production operations. The commodity pulp may be a pulp product that has been significantly dewatered in the final stages of the pulp processing. The commodity pulp can further be formed into bales (bales) or rolls (rolls) of dewatered pulp. The commodity pulp may be transported to other locations for subsequent use.

One particular process for producing commercial pulp using diverse ionic compounds prior to pulp drying is described in U.S. patent No.8,916,024. According to this process of USP 8,916,024, the pulp is treated with a combination of cationically and anionically charged compounds prior to drying, and more particularly, the treatment involves treating the pulp with a combination of at least one cationic polymer and at least one anionic polymer effective to form polyelectrolyte complexes in the treated pulp. Us patent No.6,706,144 shows a dewatering process for dewatering aqueous cellulose pulp slurry, which may be a commercial pulp slurry, wherein a mixture of one or more non-ionic surfactants and one or more anionic surfactants is added to the slurry.

The present researchers have recognized that the rate of pulp dewatering achievable in the production of commodity pulp in a pulp mill can significantly affect the overall line speed and production capacity of the pulp mill or similar production equipment. The present investigators have recognized a need for new production methods and systems for producing commodity pulp with improved pulp dewatering performance and efficiency.

Disclosure of Invention

It is a feature of the present invention to provide a method of producing commodity pulp by: the pulp is treated with one or more anionic charged compounds and with one or more enzymes to improve one or more properties of the commodity pulp or a process of making the commodity pulp, for example, to improve dewatering performance and efficiency.

Another feature of the present invention is to provide a method of producing a commodity pulp by: anionic surfactant(s) and one or more enzymes are added sequentially to the pulp prior to dewatering to improve pulp drainage.

It is another feature of the present invention to provide a system for producing commodity pulp that is capable of using one or more anionic charged compounds and one or more enzymes to improve pulp drainage prior to drying of the pulp.

It is a further feature of the present invention to provide a commodity pulp comprising dewatered pulp comprising one or more anionic charged compounds and one or more enzymes from the pulp treatment process.

Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention relates in one embodiment to a method for producing a commodity pulp, comprising forming cellulose particles into a pulp; adding at least one anionic charged compound and at least one enzyme to the pulp to provide a treated pulp; mechanically dewatering the treated pulp to provide a mechanically dewatered pulp; and thermally drying the mechanically dewatered pulp to form a commodity pulp.

The invention further relates to a process for producing a commodity pulp comprising forming cellulose particles into a pulp; adding at least one anionic surfactant and at least one enzyme to the pulp prior to dewatering; mechanically dewatering the pulp; and thermally drying the dewatered pulp to form a commodity pulp.

The invention further relates to a system for producing a commodity pulp comprising a supply of cellulose fibres (supply); at least one pulp forming unit for forming pulp from the cellulose fibers; at least one feeding device for feeding at least one anionic charged compound, such as an anionic surfactant, to the pulp; a feeding device for feeding at least one enzyme to the pulp; at least one dewatering device for mechanically removing water from the pulp; and a dryer for thermally removing water from the pulp to provide a commodity pulp.

The invention further relates to a commercial pulp comprising dewatered pulp comprising at least one anionically charged compound and at least one enzyme from the treatment process shown.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention as claimed.

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate some embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

Fig. 1 is a process flow diagram for producing commodity pulp according to one example of the present application.

Fig. 2 is a schematic diagram showing a portion of the system in fig. 1 including a pulp dryer for bleached pulp according to one example of the present application.

Fig. 3 is a schematic view of a pulp dryer that may be used in the system shown in fig. 1 according to an example of the present application.

Fig. 4 is a graph showing the amount of water (in grams) removed from wet pulp over time for various examples, including examples of the invention.

Fig. 5 is a bar graph showing the volume of water (in ml) drained from wet pulp for three drainage times for various examples, including examples of the invention.

Detailed Description

The present invention relates to the production of commercial pulp that has been treated with one or more anionic charged compounds and with one or more enzymes to improve the dewatering performance of the pulp and its efficiency and/or other properties. As used herein, "commercial pulp" refers to mechanically dewatered pulp that has been thermally dried. The commodity pulp provides the following product materials in dry form: which has useful storage stability and can be transported and disposed of more easily than a larger volume of pulp product in aqueous form. The commodity pulp may be stored, transported, or both for subsequent use as process material in other production processes. The commodity pulp can optionally be securely packaged as a containerized product for transport or shipment for further processing such as papermaking. As an option, the commercial pulp as referred to herein may be a product of a modified pulp mill adapted according to the options of the present invention for treating the pulp after any bleaching and before final dewatering with anionic charged compound(s) and one or more enzymes.

These treatment additives affect the dewatering performance in a significant and beneficial way as follows: which is unexpected from the use of either of the anionic charged compound and the enzyme alone, and in some options may exceed the additive effect expected from the individual components. Treating the pulp with the anionic charged compound and the enzyme in combination can provide a synergistic effect on water removal much better than either treatment alone and much better than the expected additive effect. It has been observed that high basis weight of some pulp sheets on e.g. a pulp dryer can be an obstacle to good drainage. It has been found that in the production of commercial pulp a significant improvement of the dewatering performance at the pulp dryer can be provided by: the pulp is treated after defibration, or other mode of defibration, and any bleaching, and before the pulp is dried with an anionic charged compound and an enzyme, which are used in the combined treatment of the pulp. Treating the pulp with a combination of anionic charged compound and enzyme(s) prior to the pulp dryer can, for example, increase the free drainage rate of the pulp. Increasing the free drainage rate of the pulp allows for increased production speeds and capacities for use in commercial pulp production processes. As an option, the pulp treatment method and system of the present invention is not part of, nor integrated with, the paper machine.

While not wishing to be bound by any theory, enzymes may provide other mechanisms to improve water removal from the pulp in the methods and systems of the invention. The surface of the fibers is hydrophilic and therefore some of the water in the slurry is strongly bound to the fiber surface and is not easily removed by gravity drainage, by the applied vacuum, or by pressing. Cellulase enzymes can remove this amount of strongly bound water, for example, by: a portion of the fibrils are removed from the surface of the fiber, thereby reducing the effective surface area available for binding water. The fiber surface is composed of hemicellulose in addition to cellulose. These hemicellulose compounds are particularly likely to bind water to the fiber surface. The use of hemicellulase-like enzymes can remove a portion of the hemicellulose (e.g., xylan or mannan) from the surface of the fibers and thus also reduce the affinity of water for the fibers.

The anionic charged compound(s) may be one or more anionic compounds and/or may be one or more anionic surfactants. Examples include, but are not limited to, alcohol sulfates or esters, alcohol alkoxy sulfates or esters, sulfonates, sulfosuccinates with (with) ethoxylated alcohols, and any soluble or dispersible salts thereof, or any combination thereof. Sulfonate refers to a salt or ester of a sulfonic acid. Sulfosuccinates refer to sulfonate derivatives of succinates (e.g., salts or esters of sulfosuccinic acid). For salts thereof, the counter ion can be a metal ion, such as an alkali metal (e.g., sodium, potassium). More specific examples include, but are not limited to, fatty alcohol sulfates or esters (e.g., C12-18 fatty alcohol sulfates or esters), alkyl alcohol sulfates or esters (e.g., C10-C16 alkyl alcohol sulfates or esters), ethoxylated alcohol sulfates or esters (e.g., ethoxylated C4-C12 alcohol sulfates or esters), sulfonated fatty acid alkyl esters, olefin sulfonates, paraffin sulfonates, alkylbenzyl sulfonates, and dialkyl sulfosuccinates. Additional examples include lauryl alcohol sulfate or ester, cetyl alcohol sulfate or ester, lauryl ethoxy sulfate or ester, myristyl ethoxy sulfate or ester, decyl benzene sulfonate, myristyl sulfonate, stearyl sulfonate, 3-hydroxy-1-hexadecane sulfonate, 2-hexadecene-1-sulfonate, dioctyl sulfosuccinate sodium salt, or others. The anionic charged compound can be an anionic surfactant that is a sulfate surfactant, a sulfonate surfactant, a sulfosuccinate surfactant, or any combination thereof.

The enzyme component of the enzyme used with the anionic charged compound(s) according to the present invention to treat pulp may include, for example, an enzyme having cellulolytic activity, hemicellulolytic activity, pectinolytic activity, or glycosidic lytic activity. The enzyme may be a hydrolase having the following activity: which affects the hydrolysis (e.g., hydrolytic activity) of the fiber, e.g., to accelerate hydrolysis of chemical bonds. The enzyme may be, for example, a cellulase, a hemicellulase, a lipase, a pectinase, a cellobiase, a xylanase, a protease, a mannanase, a beta-glucanase, a carboxymethylcellulase (CMC enzyme), an amylase, a glucosidase, a galactosidase, a laccase, or any combination thereof. A single type of enzyme or a combination of two or more different types of enzymes may be used along with the anionic charged compound(s).

Cellulases are generally enzymes that degrade cellulose, which is a linear glucose polymer found in the cell wall of plants. The cellulase-like enzyme may be, for example, a cellulase such as an endocellulase, an exocellulase, a cellobiase, an oxidative cellulase, a cellulose phosphorylase, or any combination thereof. Hemicellulases (e.g., xylanases, arabinases, mannanases) are commonly involved in the hydrolysis of hemicellulose, which, like cellulose, is a polysaccharide found in plants. Pectinases are generally enzymes that participate in the degradation of pectin (a carbohydrate with a sugar acid as a major component). Beta-glucanases are enzymes involved in the hydrolysis of beta-glucans (which are also similar to celluloses, since they are linear polymers of glucose).

The following paragraphs provide examples of enzymes that may be used in the present invention, either individually or in any combination.

Useful endoglucanases are, for example, endoglucanases having a binding domain (e.g.,

476, Novozymes), endoglucanases rich in high cellulase units (e.g.,

51081, Novozymes), or combinations thereof, or other known or useful endocellulases.

Liquid enzyme compositions containing cellulases may be referred to by the names

And

188 (both supplied by Novo Nordisk).

Obtainable from Novo Nordisk

Products, and from Alko Biotechnology

The products are two examples of commercially available liquid enzyme compositions containing xylanase-based bleaching enzymes.

As a class, hemicellulases may include hemicellulase mixtures and galactomannanases. Commercial liquid enzyme compositions containing hemicellulase enzymes as are available from Novo

From AlkoBiotechnology

And all as Novo Nordisk products

280 and Gamanase^TMAnd (4) obtaining. The mannanase can be, for example, an endo-mannanase such as endo-beta-mannanase. Mannanase preparations, including types that can be made by means of genetically modified microorganisms (e.g., bacillus-and trichoderma-types), are, for example, commercially available.

Pectinases include endo-polygalacturonase, exo-polygalacturonase, endo-pectate lyase (trans-elimination enzyme), exo-pectate lyase (trans-elimination enzyme), and endo-pectin lyase (trans-elimination enzyme). ComprisesCommercial liquid enzyme compositions of the pectinase class may be named Pectinex^TMUltra SP and Pectinex^TMBoth obtained from NovoNordisk.

The β -glucanases consist of: porphyrase, laminarinase, and exoglucanase. Commercial liquid enzyme compositions containing β -glucanases are available under the following names:

234、

BAN、

and

all of which are supplied by Novo Nordisk.

The enzymes are commercially available in ready-to-use formulations from suppliers such as those indicated herein or other suppliers. The enzyme may be in the form of a dry powder or granulate, a non-dusting granulate, a liquid, a stabilized liquid, or a stabilized protected enzyme, or other form suitable for addition to a fiber slurry or similar fiber-containing material. The liquid enzyme preparation may be stabilized, for example, according to established processes by adding stabilizers such as sugars, sugar alcohols or further polyols, and/or lactic acid or further organic acids. The dry powder form may be freeze-dried and include a matrix.

The enzyme and anionic charged compound(s) components may be premixed into a common composition for treating pulp, or they may be added separately. If pre-mixed, an enzyme pre-formulated into a liquid composition may be used as the source of the enzyme in combination with the anionic charged compound(s) component. The cellulolytic enzyme composition may contain, for example, about 5 wt% to about 20 wt% enzyme. These enzyme compositions may further contain, for example, polyethylene glycol, hexylene glycol, polyvinylpyrrolidone, tetrahydrofurfuryl alcohol, glycerol, and/or water, and/or other conventional enzyme composition additives, as described, for example, in U.S. Pat. No.5,356,800, which is incorporated herein by reference in its entirety. If an enzyme substrate is present with the enzyme in dry powder form, the substrate should not adversely interact with or interfere with the pulp treatment or other papermaking process.

Other suitable enzymes and enzyme-containing compositions include, for example, those described in: U.S. Pat. No.5,356,800, U.S. Pat. No.4,923,565, and International patent application publication No. WO 99/43780, all of which are incorporated herein by reference in their entirety. Other exemplary papermaking pulp treatment enzymes are

2523 and

2524 both available from Buckman Laboratories International, inc., Memphis, Tenn.

The enzyme may be added, for example, in an amount of from about 0.0001% to about 5% by weight enzyme, based on the dry weight of the pulp, or from about 0.0005% to about 4.5% by weight, or from about 0.001% to about 4% by weight, or from about 0.005% to about 3.5% by weight, or from about 0.01% to about 3% by weight, or from about 0.05% to about 2.75% by weight, or from about 0.1% to about 2.5% by weight, or from about 0.2% to about 1.5% by weight, or from about 0.001% to about 0.1% by weight, or from about 0.005% to about 0.5% by weight enzyme, based on the dry weight of the pulp, although other amounts may be used. These amounts of enzyme added relative to the pulp may be suitable for use of a pre-mix of the enzyme and anionic charged compound(s) in a common composition, as well as other addition options indicated herein for introducing the enzyme and anionic charged compound(s) independently to the pulp (simultaneously or sequentially). Any amount, percentage, or ratio of enzymes described herein can be calculated as active enzymes. For example, an amount of enzyme referred to as 1% by weight enzyme may refer to 1% by weight active enzyme.

Treating the pulp with a combination of at least one anionic charged compound and at least one enzyme prior to dewatering beneficially affects the drainage and dewatering behavior of the treated pulp. The at least one anionic charged compound and the at least one enzyme may for example be added sequentially to the pulp by their separate addition at different process locations, or at the same process location at different times, or they may be added simultaneously at least partially at the same process location (e.g. as separate feeds or as a premix). As an option, the commercial pulp may be produced by: at least about 80% up to 100% by weight of the total addition amount of the anionic charged compounds is added sequentially after the addition of the at least one enzyme before dewatering the pulp. In such an option, the enzyme is given the opportunity to interact first with the pulp fibers, and then with the anionic charged compound. Adding the at least one anionically charged compound and the at least one enzyme in this order may amplify the achievable enhancement of the dehydration performance. As another option, at least a portion or all of the anionic charged compound may be added to the pulp before the enzyme is added to the pulp. By the present invention, the pulp drainage performance in the production of commercial pulp can be significantly improved, for example by one, two, or more than three times, by the process of the present invention, compared to the pulp drainage seen in the case where no anionic charged compound or enzyme is added, or in the case where only the anionic charged compound is used alone or the enzyme is used alone for the pulp. Further, by adding the at least one anionically charged compound and the at least one enzyme in combination to the pulp, the drainage efficiency may be significantly increased, e.g., by about 60% to about 200%, or other increased amount, as compared to when only anionically charged compounds are used alone or when enzymes are used alone to treat the pulp. Furthermore, a water discharge rate exceeding the sum of the water discharge rates alone obtained by using the anionic charged compound alone or the enzyme alone for treating pulp can be achieved. Better drainage in the wire section of the pulp dryer can lead to reduced moisture of the pulp in the press section and as a result the steam consumption in the drying section can be significantly reduced, which provides energy savings. Further, the improvement in dewatering of pulp provided by subjecting the digested pulp to the treatment according to the invention before the pulp is dried may allow for faster pulp passage rates or speeds in the pulp mill, whereby the production rate of the pulp mill may be increased. The overall polymer addition rate, which can be reduced, provides an appropriate amount of pulp dewatering compared to that expected if the anionic charged compound was used alone. The free drainage properties of the pulp treated with the present invention before the pulp is dried may exhibit a good correlation with the water retention properties (e.g. in terms of water retention value or WRV) of the treated pulp, indicating that the treatment may yield reliable non-randomized results.

As an option, treating the pulp with at least one anionic charged compound and at least one enzyme combination prior to dewatering in the production of commercial pulp is effective to provide at least one of:

(i) pulp free drainage (g/90 sec) increased to the following values: at least 7.5% greater, or at least 10% greater, or at least 15% greater, or at least 25% greater, or at least 50% greater, or at least 75% greater, or at least 100% greater (one time), or at least 200% greater (two times), or at least 300% greater (three times), or at least 400% greater (four times), or at least 500% greater (five times) than the free drainage value obtained without any treatment in the pulp;

(ii) pulp free drainage increased to the following values: at least about 3%, or at least about 10%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 75%, or at least about 100% greater than the free drainage value obtained if the anionic charged compound (e.g., anionic surfactant) was used alone in the pulp (without the use of the enzyme);

(iii) pulp free drainage increased to the following values: at least about 10% greater, or at least about 15% greater, or at least about 20% greater, or at least about 25% greater, or at least about 30% greater, or at least about 40% greater, or at least about 50% greater, or at least about 60% greater than the free drainage value which is the sum of the free drainage enhancement amounts obtained from using the anionic charged compound (e.g., anionic surfactant) and enzyme, respectively and alone, in the pulp; and

(iv) Pulp retention value (WRV) reduced to the following value: which is at least about 10% less, or at least 15% less, or at least about 20% less, or at least about 25% less than the WRV obtained if the anionic charged compound (e.g., anionic surfactant) was used alone in the pulp (without the use of the enzyme). In calculating the percentage values of (i), (ii), (iii), and (iv), the denominator value of the score is based on the value of the pulp treated with only one of the anionic charged compounds or enzymes or not treated with any of the anionic charged compounds or enzymes, and the molecular value is the absolute value of the difference between the property values of the pulp treated with the dual treated anionic charged compounds/enzymes and the pulp treated with only one of the anionic charged compounds/enzymes or not treated with any of the anionic charged compounds/enzymes. (i) The water removal measurements of (i), (ii), (iii), and (iv) can be obtained using a Mutek DFR-05 drainage/water retention tester. The water retention freedom of the martekdfr-05 drainage simulates the water retention and drainage conditions prevailing in the pulp and paper machine.

These and/or other effects of the invention may be provided by treating the pulp with one or more anionic charged compounds and one or more enzymes without the need to co-add or co-exist any non-ionic or cationic charged compounds, such as non-ionic surfactants, cationic polymers, or cationic flocculants, to the pulp under treatment. As an option, the pulp slurry treated with the anionic charged compound and the enzyme may be free or substantially free of nonionic surfactant and/or cationically charged compound, as the benefit obtained by the present invention is independent of the co-presence of such nonionic surfactant or cationically charged compound. As regards the added nonionic surfactant, as an option the pulp may be treated with a nonionic surfactant of less than 0.1 kg/metric ton dry fibre, or less than 0.05 kg/metric ton dry fibre, or less than 0.01 kg/metric ton dry fibre, or less than 0.001 kg/metric ton dry fibre, or less than 0.0001 kg/metric ton dry fibre, based on the total nonionic surfactant, or in the absence of nonionic surfactant. As regards the added cationically charged compound, as an option the pulp can be treated with less than 0.1 kg/metric ton dry fiber, or less than 0.05 kg/metric ton dry fiber, or less than 0.01 kg/metric ton dry fiber, or less than 0.001 kg/metric ton dry fiber, or less than 0.0001 kg/metric ton dry fiber of a cationically charged compound (e.g. cationic surfactant(s), cationic polymer (s)), cationic flocculant(s), etc.) or in the absence of a cationically charged compound, based on the total cationically charged compound.

The methods of the present invention can be used to improve dewatering of a pulpeable material, including a cellulosic pulpeable material, a non-cellulosic pulpeable material, a recycled paper waste pulpeable material, or any combination thereof. As an option, the cellulosic pulpable material can be lignocellulosic. The drainage and dewatering improvements due to the pulp treatment according to the method and system of the invention are not limited to the treatment of any particular type of pulp and may find application in all grades of pulp. The treatable pulp may be chemical pulp, mechanical pulp, or a combination of these types of pulp. As an option, the treatable pulp is at least partially chemical pulp. The treatable pulp may be bleached or unbleached at the time of treatment. The treatable pulp may include, for example, kraft pulp, dissolving pulp, fluff (paper) pulp, semichemical (e.g., bleached chemithermomechanical pulp or BCTMP), sulfite pulp, alkaline pulp, organosolv pulp, polysulfide pulp, or other pulp, and any combination thereof. Non-chemimechanical pulp, e.g., pulp that is only mechanically defibered (e.g., by defibering the raw material using only a millstone or cone refiner), can also be processed with the pulp treatment shown.

As used herein, "dried pulp" refers to coated, stacked, palletized, or otherwise physically accumulated pulp that is sufficiently dewatered to be exposed to air and is not suspended and submerged in an aqueous medium.

"anionically charged compound" refers to a compound that has a net negative charge on the molecule in aqueous solution. The anionic charged compound may be organic or inorganic. "organic" means a compound containing at least one C-H bond.

"enzyme" refers to a protein capable of catalyzing a chemical reaction.

"surfactant" refers to an organic compound that can lower the surface tension of a liquid, the interfacial tension between two liquids, or the interfacial tension between a liquid and a solid.

"anionic surfactant" refers to a surfactant having a net negative charge on the molecule in aqueous solution. Thus, the anionic surfactant may have only an anionic moiety as the charged group thereon, or may be amphoteric and have a net anionic charge for the entire molecule.

"nonionic compound" refers to a compound that is amphiphilic and has no charged groups at either of its terminal groups.

"nonionic surfactant" refers to a surfactant that is amphiphilic and has no charged group at either of its terminal groups.

"cationically charged compound" refers to a compound that has a net positive charge on the molecule in aqueous solution. The cationically charged compound can be organic or inorganic.

"cationic surfactant" refers to a surfactant having a net positive charge on the molecule in aqueous solution. Thus, the cationic surfactant may have only cationic moieties as charged groups thereon, or may be amphoteric and have a net cationic charge for the entire molecule.

"cationic polymer" refers to a polymer having a net positive charge on the molecule in aqueous solution. Thus, the cationic polymer may have only cationic moieties as charged groups thereon, or may be amphoteric and have a net cationic charge for the entire molecule.

"kraft pulp" refers to chemical wood (paper) pulp produced by digesting wood by the kraft process.

"fluff pulp" refers to chemical, mechanical, or a combination of chemical/mechanical pulps, typically bleached, used as absorbent media in disposable diapers, bed pads, and other personal hygiene products. Fluff pulp is also referred to as "fluff" or "fluff" pulp.

"dissolving pulp" refers to a higher purity premium pulp made for processing to cellulose derivatives (including rayon and acetate).

"bleached chemithermomechanical pulp" or "BCTMP" refers to bleached CTMP. "CTMP" refers to chemi-mechanical pulp produced by treating wood chips with chemicals (e.g., sodium sulfite) and steam prior to mechanical defibration.

"containerization" refers to the process by which multiple market fibers can be bundled or packaged together for disposal as a single unit product.

"defibering" refers to the separation of wood fibers by mechanical means, chemical means, or a combination of both.

Referring first to fig. 1, wood chips, or other comminuted cellulosic or non-cellulosic fibrous material, is fed through line 10 to a continuous digester 12, or one or more batch digesters, in which the pulp is subjected to the pulping action of a pulping liquor fed thereto through line 14. This option can for example be described by specific reference to a kraft process applied to virgin lignocellulosic fibrous material, wherein the digested and optionally bleached pulp is treated with an anionic charged compound or surfactant and an enzyme, after which the kraft pulp is dried and containerized. It will be appreciated that the invention is also applicable to other pulping procedures with suitable modifications in view of treating the pulp with an anionic charged compound or surfactant and an enzyme prior to drying the pulp. As an option, in the kraft process, the active pulping chemicals may be sodium hydroxide and sodium sulfide, also known as white liquor, and these chemicals may be included in the pulping liquor fed through line 14. The digester can be operated in a batch or continuous mode. It is generally known that there are variations to the cooking (cooking) process for both batch and continuous digesters that can be used. In a continuous digester, for example, wood chips or other particulate feedstock material may be fed at a rate that allows the pulping reaction to complete by the time the material exits the reactor. As an option, delignification may, for example, require cooking at about 100 ℃ to about 200 ℃ (266 ° F to 356 ° F) for hours, or other temperature and cooking time conditions suitable for the feedstock and cooking chemicals used for the digestion. Typically, the chips that have completed the cooking are blown (low) by reducing the pressure to atmospheric pressure. This releases steam and volatiles. As an option, after digestion, the resulting digested wood pulp containing residual spent pulping liquor can be conveyed via line 16 to brown stock washing zone 18. The washing zone 18 may be used to wash the digested sheet free of entrained spent pulping liquor and to screen out unwanted materials. Screening of the pulp after pulping may be a process in which the pulp is separated from large lumps, dust and other debris. The "accept" is pulp that can be further processed according to the invention and the material separated from the pulp is "reject". The brown stock from the blow can be passed to a washing stage where the cooking liquor used is separated from the cellulose fibres. Typically, a pulp mill may have multiple washing stages in series. The spent pulping liquor, or black liquor 15, may be fed to a recovery and regeneration zone (not shown) that may operate according to conventional methods.

As an option, the pulp in line 16 may be washed in a brown stock washing section 17 (e.g. by successive passes through a washer and a screen), after which unbleached pulp 19 is discharged from the brown stock washing section 17 through line 18. As one option, the unbleached pulp may be bleached at a bleaching apparatus 22, after which the resulting bleached pulp is dried at a pulp dryer 24 to provide a commodity pulp 26. In this bleaching option, unbleached pulp 19 is fed to bleaching plant 22 via line 20. As an option, the pulp exiting the digester wash unit may retain a dark brown color due to residual lignin content (which it is desired to bleach away, which may depend on the intended end use). If bleached, conventional bleaching processes may be used on the pulp. As an option, the pulp may be subjected to one or more bleaching, alkaline extraction, and washing operations in the bleaching plant 22, which may result in further delignified and bleached pulp having increased brightness. The bleaching treatment chemical may be, for example, oxygen, ozone, chlorine dioxide, chlorine, peroxide, pure acid or alkali as appropriate for the extraction step, or a mixture of these, and possibly other bleaching chemicals or additives. For example, for bleaching, a pair of chlorine dioxide and caustic extraction towers followed by a pulp washing stage may be used, or other conventional pulp bleaching arrangements may be applied to the pulp.

The bleached pulp may be discharged from the bleaching plant 22 through line 23 for transport to a pulp dryer 24. As a further option, unbleached pulp may be fed directly from the washing section 17 to the pulp dryer 24 without any intermediate bleaching of the pulp, as indicated in fig. 1 by line 21. For example, where the apparatus is designed to produce pulp to make brown (unbleached) pocket paper or liner for boxes, packaging, etc., the pulp may not need to be bleached to a high brightness. The pulp dryer 24 can dewater and heat dry the bleached or unbleached pulp to provide a dried pulp in line 25, which is a commodity pulp. The pulp dryer 24 may include, for example, a mechanical dewatering section and a thermal drying section (which are described herein in further detail and illustration with respect to other figures). The commodity pulp 26 may be in the form of, for example, a continuous sheet of dried pulp, or other dried form of pulp discharged from the pulp dryer 24.

As an option, the pulp is treated with the addition of at least one anionic charged compound and at least one enzyme before dewatering and drying the pulp in the pulp dryer 24. As an option, the enzyme may be added to the pulp in feed line 27 and the anionic charged compound may be added at the inlet side of the pulp dryer 24 in feed line 28. Adding at least one anionic charged compound and at least one enzyme to the pulp prior to the dryer 24 can improve dewatering performance at the dryer 24. As an option, for bleached pulp, at least one anionic charged compound and at least one enzyme may be added to the pulp at any location after the bleaching apparatus 22 and before the dryer 24. As another option, for unbleached pulp, at least one anionic charged compound and at least one enzyme may be added to the pulp at any location after digester 12 and before dryer 24. As an option, the anionic charged compound is added to the pulp no earlier than the addition of the enzyme to the pulp. As an option, the anionic charged compound is added to the pulp at a time that may partially overlap with the time of addition of the enzyme. As an option, the entire amount of enzyme is added to the pulp before the entire amount of anionic charged compound is added to the pulp. As an option, about 80% -100%, or about 85% -100%, or about 90% -100%, or about 95% -100% by weight of the total weight of the enzyme is added to the pulp before the earliest addition of the anionically charged compound to the pulp. Additional details and explanations regarding the addition of the indicated treatment compounds to the pulp prior to the dryer are provided in the discussion of the other figures herein.

The commodity pulp 26 discharged from the pulp dryer 24 may optionally be packaged at one or more stations 29. As an option, to containerize the commodity pulp, the dried pulp from the pulp dryer is formed into bales or rolls, or other safe large-scale units of pulp fibers. The containerization mode of the commodity pulp need not be limited as long as the bales, rolls or other bundles of dried pulp fibers are secured together for transport and disposal as a single unit product. As an option, a continuous sheet of dried pulp may be produced by the pulp dryer, which may be formed into bales or rolls. As an option, the continuous sheet of dried pulp formed at the pulp dryer may be cut into small sheets and stacked into bales. Pulp bales may be compressed, wrapped, and bundled into a strong bundle for storage and transport. Both the slip-inserted bale and the flash-dried bale can be containerized for disposal and transport. As an option, the bulk may comprise a wire or a strap-bound bundle of cut pieces of dried pulp, or a wire or a strap-bound flash-dried bundle of dried pulp. For example, as an option, one unit of about 7-9 bundles can be securely wire-bound with 6-9 strands of thick steel wire. The containerized bales of dried pulp with interleaving paper inserted or flash dried bales provide containerized commodity pulp. The bale with inserted liner paper may have a weight of about 250kg or other weight, which may be sized approximately 27-32 inches wide, 35-37 inches long, and 17-18 inches high, or other dimensions. A less dense pressed flash-dried bale may also be provided, which may weigh about 195 to about 200kg, or other weights. Other sizes and weights of the dried pulp bales can be packaged. As another option, the commodity pulp may be packaged in rolls or rolls (reel), as shown. For example, a roll of commodity pulp may be formed that may be sized to have a width of about 7 to about 55 inches and a diameter of about 58 to 60 inches, or other dimensions. The pulp roll may optionally be wrapped with a removable cover using cardboard (cover sheeting), thread or tape, or both. As an option, the commodity pulp may be stored and/or transported in a non-containerized or containerized form to a paper mill within or outside of the premises relative to the pulp mill in which the commodity pulp is produced. The commercial pulp may be used in papermaking (e.g., in a papermaking process by repulping the dried pulp) or other uses.

Fig. 2 shows further details regarding a portion of the bleached pulp dryer 224 and associated pulp feed and pretreatment systems according to one option of the present invention. Bleached pulp is withdrawn from one or more bleaching towers 222A, 222B at a bleaching plant (e.g., bleaching plant 22 in fig. 1) and transferred through line 223 to a surge tank 227 and from there to a machine chest 229. The bleached pulp may be mixed in the surge tank 227 until a substantially uniform dispersion is achieved. The bleached pulp in the surge tank 227 may be transferred to the machine tank 229. The machine chest 229 may be a consistency leveling chest that provides a residence time for the pulp that may be sufficient to allow for leveling of the change in consistency entering the chest in a known manner. The pulp content of the machine chest 229 may be fed into the pulp dryer section 224 via a machine chest pump 231.

The pulp dryer section 224 may include a mechanical dewatering section 224A and a thermal drying section (not shown in this figure). Of these sections, only a portion of the mechanical dewatering section 224A is shown in fig. 2 and additional information about this section and other subsequent processing sections is provided in the discussion of the other figures herein. As an option, the pulp pumped from the machine chest pump 231 can be mixed with and diluted with white water 233 from the white water silo 201 to form a stream of diluted pulp 226. Pulp 226 is pumped by pump 203 through a centrifugal screen 235 to the headbox 205, from which headbox 205 the pulp is sprayed or otherwise deposited onto the wire 207. As an option, the pump 203 may be a centrifugal pump called a fan pump. The pulp 208 collected on the wire 207 is forwarded to a wet press (not shown) for further dewatering of the process water, then thermally dried and packaged (which is described in more detail herein with respect to other figures). As an option, the white water silo 201 may form part of a white water recirculation loop including lines 206 and 233 and the silo 201 (such as shown in fig. 2) integrated with the mechanical dewatering section 224A of the pulp dryer 224. For example, filtrate 206 (also referred to herein as white water) discharged from the wire 207 may be recycled to the white water silo 201 for reuse as white water 233 in combination with fresh pulp to form a combined stream of pulp 226.

The treatment of the pulp 226 may include one or more introduction points for each of the at least one anionic charged compound and the at least one enzyme before the resulting treated 236 pulp reaches the headbox 205 and the wire 207. As an option, an anionic charged compound is added to the pulp before the enzyme, such as shown in fig. 2. For example, an enzyme may be added at the inlet side of the fan pump 203 using the feed device 202, and an anionic charged compound may be added at the discharge side of the fan pump 203 using the feed device 204. As an option, this sequence of addition of at least one anionic charged compound and at least one enzyme may be provided at other locations between the bleaching towers 222A, 222B and the headbox 205 of the mechanical dewatering section 224A. As shown, as part of the mechanical dewatering section, the wet fibrous sheet formed from the treated pulp as collected on the wire 207 may be further drained and mechanically pressed, and the screened and pressed pulp may then be thermally dried, after which the resulting dried pulp is conveyed to one or more containerized stations.

Referring to fig. 3, as an option, the digested and optionally bleached pulp slurry 323 is combined with white water from the white water silo 306 and the resulting diluted pulp 326 may be pumped to the headbox 305 via the fan pump 303. As an option, the enzyme from the supply and feed device 302 may be added to the pulp 326 at the inlet side of the pump 303 and the anionically charged compound from the supply and feed device 304 may be added at the outlet side of the fan pump 303. The at least one anionic charged compound and the at least one enzyme may interact with the pulp fibers and contents while feeding the pulp toward the headbox by the pumping action of the fan pump and prior to discharge from the headbox onto a wire or screen for dewatering. The at least one anionic charged compound and the at least one enzyme may interact sufficiently with the pulp fibers to substantially improve drainage and dewatering efficiency of the pulp on the wire as compared to the same pulp without the use of the at least one anionic charged compound and the at least one enzyme or pulp treated with only one of the at least one anionic charged compound and the at least one enzyme.

From the headbox 305, the pulp may be ejected onto a wire 307 where the pulp slurry is dewatered and formed into a wet pulp fiber sheet. As an option, the pulp may be supplied to the headbox at a consistency of between 0.1% and 5% solids, or from about 0.5% to about 3% solids, or from about 1% to about 2.5% solids by weight. The pH of the treated pulp supplied to the headbox 305 can be, for example, from about 4 to about 9, or from about 4.5 to about 8.0, and can be controlled within these ranges by the addition of pH modifiers if desired or necessary. As an option, the pulp may leave the headbox 305 through a rectangular opening of adjustable height, called a sluice (slice), which stream lands and spreads on the wire 307. The mesh may be a continuous metal screen or plastic mesh with small holes running in a loop. The web may be, for example, a flat wire Fourdrinier, a twin wire former, or any combination of these. Low vacuum boxes and suction boxes may be used with the web in a conventional manner. As an option, the sheet consistency of the pulp after dewatering on the wire may be, for example, from about 2% to about 35%, or from about 10% to about 30% by weight, on a% solids content basis, or other values. Conventional wire or screen arrangements for dewatering pulp may be suitable for use in the method and system of the present invention. The filtrate portion 306 (also referred to herein as white water) withdrawn and discharged through the wire 307 can be recycled to the white water silo 301 (as shown) and then can be combined with fresh pulp 323 before the resulting diluted pulp 326 is pumped to the headbox 305.

The pulp 308 collected on the wire 307 may be advanced to a wet press section 309. Additional water may be pressed and vacuum extracted from the pulp 308 at the wet press section 309. As an option, the press section 309 may remove water from the pulp by a system of nips assisted by press felts formed by rolls pressed against each other, which press felts support the pulp sheet and can absorb the pressed-out water. A vacuum box, such as a suction box, may optionally be used, for example, to apply a vacuum to the press felt to remove moisture so that it does not add moisture to the sheet when the felt returns to the nip on the next cycle. As an option, the pulp sheet may be passed through a series of rotating rolls ("presses") that squeeze out water and air until the pulp sheet has a fiber consistency of about 40% to about 50% by weight. As an option, the pressed pulp may contain up to about 50% solids, or from about 20% to about 45% solids, or other values after pressing.

The screened and pressed pulp 310 may be moved to a thermal dryer section 311 for evaporative drying. Heat may be used at thermal dryer section 311 to remove additional water (e.g., by evaporation). As an option, the pulp 310 may be dried in a thermal dryer section 311 at a temperature in the range of 60 ℃ to 127 ℃ (140 ° F to 260 ° F) to remove more water. Making As an option, the thermal dryer may have, for example, a series of internally steam heated cylinders that evaporate the moisture of the pulp as it travels over the heated cylinders. As an option, the pressed pulp sheet may be floated through a multi-tier (multi-store) sequence of hot air dryers to a consistency of about 80% to about 97% by weight consistency, or about 85% to about 95% by weight, or other values. As an option, the dried pulp exiting the pulp dryer has an absolute moisture content (i.e., total H based on the total weight of the pulp) of less than about 20 wt%, or less than about 15 wt%, or less than about 10 wt%, or from about 5 wt% to about 20 wt%, or from about 5 wt% to about 10 wt%₂O content). For example. A dried pulp containing 12 total weight parts water (all forms) and 100 weight parts dry pulp fibers has an absolute moisture content of 10% by weight (i.e., 12/(12+100) × 100).

The dried pulp 325 leaving the thermal dryer 311 is a commodity pulp 326. As an option, the commodity pulp 326 provided by thermal drying may be in the form of a continuous sheet of dried pulp. The commodity pulp 326 may optionally be containerized at a station or stations 327 as in fig. 1 to obtain a containerized commodity pulp 329 (e.g., in bales, rolls, or other form).

As an option, the at least one anionic charged compound and the at least one enzyme indicated for treating the pulp to improve dewatering performance may be water soluble or water dispersible compounds.

As an option, inorganic anionic coagulants such as polyphosphates, anionic silica sols, or any combination thereof may be used.

As an option, in the process of the present invention, at least one anionic charged compound may be added to the pulp in an amount of from about 0.1lb. to about 10 pounds (lb.) of anionic charged compound per ton of dry fibers, or from about 0.2 to about 8lb. of charged compound per ton of dry fibers, or from about 0.3 to about 4lb. of anionic charged compound per ton of dry fibers, or from about 0.5 to about 3lb. of anionic charged compound per ton of dry fibers (on a solids/solids basis), for example at the route to the pulp dryer as shown, or elsewhere after any bleaching and before the pulp dryer.

The enzyme may be added to the pulp in an amount of about 0.001 to about 2 pounds (lb.) active enzyme per ton of dry fiber, alternatively about 0.01 to about 1.5 lb./ton of dry fiber, alternatively about 0.1 to about 1 lb./ton of dry fiber, or other amounts.

As an option, the at least one anionically charged compound and the at least one enzyme may be added to the pulp in a total amount of about 0.2 lb./ton dry fiber to about 12 lb./ton dry fiber, or about 0.4 to about 10 lb./ton dry fiber, or about 0.6 to about 8 lb./ton dry fiber, or about 1 to about 6 lb./ton dry fiber (on a solids/solids basis), or other values. As an option, the at least one anionic compound and the at least one enzyme may be added to the pulp in a weight ratio (w: w) of about 10,000:1 to 1:10, alternatively about 1000:1 to about 1:5, alternatively about 100:1 to about 1:1, alternatively about 10:1 to about 2:1, or other ratios.

The wood chips suitable for use in the present invention for producing the commodity pulp may be derived from hardwood species, softwood species, or combinations thereof. Conifer species include, but are not limited to: fir (e.g., douglas fir and balsam fir), pine (e.g., eastern white pine (white pine north america) and loblolly pine), spruce (e.g., white spruce), larch (e.g., larch americana), cedar, and hemlock (e.g., hemlock canada and hemlock california). Examples of hardwood species include, but are not limited to: acacia, alder (e.g., red alder and european black alder), european aspen (e.g., tremble), beech, birch, oak (e.g., white oak), gum (e.g., eucalyptus and american maple), poplar (e.g., balsam poplar, eastern cotton poplar (cottonwood), black cotton poplar (black cottonwood), and american tulip), maple (e.g., maple, red maple, silver maple, and maple). These types of wood may be used alone or in any combination thereof. As an option, a combination of hemlock and cottonwood particles may be used. As an option, the wood chips to be pulped comprise virgin wood material, for example at least 50 to 100% by weight virgin wood material. As an option, other pulpable materials may be used or included in the feedstock, such as recycled fibrous materials, recycled fibers from post-consumer waste, for example, or non-wood materials such as grasses, agricultural residues, bamboo, bast materials (e.g., ramie, flax, hemp), or any combination thereof.

In addition to the at least one anionic charged compound and the at least one enzyme shaft, the pulp may be treated with one or more optional additives within the commercial pulp manufacturing system, so long as they do not interfere with the indicated function of the at least one anionic charged compound and the at least one enzyme for improving the dewatering performance of the treated pulp. A list of optional chemical additives that may be used in conjunction with the present invention include, for example, pH modifiers, dry strength agents, wet strength agents, softening agents, debonding agents, adsorbents, sizing agents, dyes, optical brighteners, chemical tracers, opacifiers, dryer adhering chemicals, and the like. Additional optional chemical additives may include, for example, pigments, lubricants (emollients), humectants (humectants), virucides, bactericides, buffers, waxes, fluoropolymers, odor control materials and deodorants, zeolites, fragrances, vegetable and mineral oils, silicone compounds, other surfactants, humectants (moisisturizers), UV blockers, antibiotic agents, lotions (precipitation), fungicides, preservatives, aloe vera extract, vitamin E, and the like. Suitable optional chemical additives may be retained by the pulp fibers and may or may not be water soluble or water dispersible. As shown, no additional addition or presence of cationically charged compounds is required in the pulp treatment of the present invention using at least one anionically charged compound and at least one enzyme to obtain an improvement in dewatering performance.

As shown, treating pulp with a combination of at least one anionic charged compound and at least one enzyme can provide significantly higher dewatering performance than when using either single chemical treatment. In some options, while the correlation of water retention (water retention) to free drainage may vary with the type of ionic charged compound and the application process, free drainage may generally exhibit a good correlation to water retention. In some options, increasing the dosage of the ionic charged compound in the pulp may slightly decrease the WRV and increase dewatering, where the improvement may eventually peak or level off as the dosage is gradually increased.

A commodity pulp product may be provided, the commodity pulp product comprising a commodity pulp or a containerized pulp as follows: having at least one anionic charged compound and at least one enzyme from the treatment process at least partially retained to the pulp fibers. The commodity pulp manufactured in the process according to the invention may comprise, for example, from about 0.001 to about 5 pounds (lb.) of anionic charged compound per ton of dry fibers, or from about 0.01 to about 3lb. of anionic charged compound per ton of dry fibers, or from about 0.1 to about 2lb. of anionic charged compound per ton of dry fibers, or from about 0.2 to about 1lb. of anionic charged compound per ton of dry fibers (on a solids/solids basis), and the enzyme may be comprised in the commodity pulp in an amount from about 0.000001 lb./ton to about 1 lb./ton of dry fibers, or from about 0.00001 lb./ton to about 0.1 lb./ton of dry fibers.

In the industrial context where commercial pulp is produced, large capital expenditures are typically required to build a huge steam operated dryer. Once it is in place, a large amount of energy is required to remove the water from the pulp. The improvement in removing water from the fiber mat as may be provided by the present invention may be used to benefit the manufacturer in several ways. If the pieces with less moisture enter the dryer, less steam is required to dry the pieces to the point where they can be transported. At the same time, an alternative is to limit the reduction of steam usage and, instead, speed up the machine. The benefit is then an increase in yield, which can be provided by the present invention.

The invention will be further clarified by the following examples, which are intended to be only exemplary of the present invention. All amounts, percentages, ratios, etc. used herein are by weight unless otherwise indicated.

Examples

Example 1:

an experiment was performed to compare the water discharge of pulp treated with the following with the water discharge of untreated pulp: an anionic surfactant alone, an enzyme alone, and combinations thereof and a separate combination of an anionic surfactant and a different enzyme added to the pulp.

Laboratory tests were conducted to perform this evaluation. As shown, a number of separate experiments were run on the pulp to compare the effect of using anionic surfactant and enzyme alone and in combination. A control test was also performed without chemical additives to the pulp.

The enzymes used in these experiments were BLX-14303 from Buckman Laboratories ("enzyme X") containing xylanase-like enzymes as active components and BLX-14350 from Buckman Laboratories ("enzyme Y") containing entirely different xylanase-like enzymes as active components. The anionic surfactant was sodium lauryl ether sulfate (3 mol EO), which was used as an aqueous solution having a concentration of 30% by weight of the anionic surfactant. The dosage rate of the anionic surfactant used was 2g anionic surfactant/kg dry fibre pulp. For each of enzyme X and enzyme Y, the dosage rate of the enzyme was 1g enzyme/kg dry fibre pulp.

The following test procedure was applied. The slurry of bleached pulp to be tested was prepared in tap water at a consistency of about 1% by weight. Water removal from the slurry was evaluated using a Mutek DFR-05 drainage/retention tester. A selected volume of this slurry (500mL) was added to a chamber with a screen at the bottom. Any anionic surfactant and/or enzyme included in the test sample is premixed with the slurry prior to addition to the chamber. The sieve is a metal mesh sieve (mesh size is 600 meshes). When the test started, water was allowed to drain from the slurry through the screen. The amount of water that freely drained from the sample, as well as the rate of drainage, was monitored. For the first 30 seconds after the beginning of the drainage from the chamber, no vacuum was applied, nor was pressure applied. At 30 seconds after the start of drainage, the test apparatus (i.e., DFR with forced dewatering (controlled mechanical level)) was used to apply pressure to the mat (i.e., the fiber mat collected on the screen). The rate of water removal from the pad was again measured. At 50 seconds, additional pressure was applied, and at 70 seconds additional pressure was again applied. The program, including the amount of pressure applied at each stage, simulates the dewatering and pressing that occurs on a paper machine or on a pulp dryer. The free drainage rate in g/30 seconds and g/90 seconds was determined based on the measurement results.

The results of these experiments are shown in tables 1 and 2. Table 1 below shows the raw data from one set of experiments and table 2 shows the deviation of the results for samples containing anionic surfactant, enzyme, or both from the control. The numbers in tables 1 and 2 are grams of water drained from the sample. The result after 30 seconds was free draining 30 seconds after the beginning of draining. The results after 90 seconds are for the total water removed after free drainage and 3 additional presses.

TABLE 1 raw data

Time of day

Sample (I)	30 seconds	90 seconds
			Control sample	345	385.5
Anionic surfactant A (30%)	349	404.5
			Anionic surfactant A (30%) + enzyme X	358	419
Anionic surfactant A (30%) + enzyme Y	359	420.5
			Enzyme Y	348.5	387

Table 2-water removal: variation from control

	30 seconds	90 seconds
			Anionic surfactant A (30%)	4	19
Anionic surfactant A (30%) + enzyme X	13	33.5
			Anionic surfactant A (30%) + enzyme Y	14	35
Enzyme Y	3.5	1.5

These experimental results show that treating pulp slurry with a combination of an anionic surfactant and an enzyme such as a cellulolytic enzyme or a hemicellulolytic enzyme together provides a good cumulative unexpected result of improving water removal. It is clear from the data that this combination provides a synergistic effect on water removal far better than either treatment alone and far better than the expected additive effect.

Example 2:

another experiment was performed to compare the water discharge of pulp treated with the following and the water discharge of untreated pulp: an anionic surfactant alone, an enzyme alone, and combinations thereof and a separate combination of an anionic surfactant and a different enzyme added to the pulp.

The laboratory tests performed were similar to those shown in example 1. Again, a number of separate experiments were run on the pulp to compare the effect of using anionic surfactant and enzyme alone and in combination. A control test was also performed without chemical additives to the pulp.

The enzyme used in these experiments was a formulation prepared from: the enzyme NS-51121 ("enzyme") available from Novozymes, which contains a xylanase-like enzyme; and an anionic surfactant (sodium lauryl ether sulphate (3 moles EO) (denoted as "surfactant") which is used as an aqueous solution in a 30% active aqueous formulation the anionic surfactant used has a dose rate of 2g of the 30% active formulation per kg of dry fibre pulp the enzyme has a dose rate of 1g of the enzyme formulation per kg of dry fibre pulp.

The test procedure used is as described in example 1. The slurry of bleached pulp to be tested was prepared in tap water at a consistency of about 1% by weight. A selected volume of this slurry (500mL) was added to a chamber with a screen at the bottom. Any anionic surfactant and/or enzyme included in the test sample is premixed with the slurry prior to addition to the chamber. When the test started, water was allowed to drain from the slurry through the screen. The amount of water that freely drained from the sample, as well as the rate of drainage, was monitored. For the first 30 seconds after the beginning of the drainage from the chamber, no vacuum was applied, nor was pressure applied. Pressure was applied to the pad 30 seconds after the start of drainage, followed by pressure again at 50 seconds and again at 70 seconds. The rate of water removal from the pad was measured. The total water removed from the pad was measured.

The results of these experiments are shown in figures 4 and 5. Figure 4 records the total water removed from the sample by the 90 second test. From the results, the addition of surfactant improves water removal, and the use of enzymes also improves water removal. The data also show that there is a difference in the effect from the enzyme compared to the effect of the surfactant. The data also demonstrate that using a combination of enzyme and surfactant, the total water removed is greater than the benefits achievable using either component alone. Further, there are some differences in the effects of the components. The enzyme provides the effect of faster initial ("free") drainage. The advantage of this effect is that more water is removed before the press. The surfactant provides better water removal in the press. The combination of these two mechanisms provides the best results.

These same data are shown in fig. 5. The total water removed at the 8 second point showed an effect on the initial free drainage. The total amount at the 30 second point is the final free drainage. Showing the positive effect of the enzyme in particular. The final measurement at the 90 second point gives the total water removed. For reference, the initial total volume of water was 495 mL.

The benefits of the invention are presented in another way in table 3. "final mat consistency" is the percentage of fibers in the final mat after pressing. The objective is to maximize pad consistency. If less water is left after pressing, less heat and steam are required to dry the mat to its final gauge. A general rule with pulp dryers is that an increase of 1% in the consistency of the mat entering the drying process results in a reduction of 4% in the energy required for drying the mat. The addition of surfactant alone or enzyme alone gives similar benefits, but the combination gives much better results.

Again, these experimental results show that treating pulp slurry with a combination of an anionic surfactant and an enzyme, such as a cellulolytic enzyme or a hemicellulolytic enzyme, together provides a good cumulative unexpected result of improving the water removal. It is clear from the data that this combination provides a synergistic effect on water removal far better than either treatment alone and far better than the expected additive effect.

The invention includes the following aspects/embodiments/features in any order and/or in any combination:

1. the present invention relates to a process for producing commodity pulp comprising:

Forming the cellulose particles into pulp;

adding at least one anionic charged compound and at least one enzyme to the pulp to provide a treated pulp;

mechanically dewatering the treated pulp to provide a mechanically dewatered pulp; and

the mechanically dewatered pulp is thermally dried to form a commodity pulp.

2. The method of any preceding or subsequent embodiment/feature/aspect, wherein at least a portion of the addition of the enzyme to the pulp occurs prior to the addition of the anionically charged compound to the pulp.

3. The method of any preceding or subsequent embodiment/feature/aspect, wherein about 80% -100% by weight of the addition of the enzyme to the pulp occurs prior to the addition of the anionic charged compound to the pulp.

4. The method of any preceding or subsequent embodiment/feature/aspect, wherein the anionic charged compound is an organic anionic charged compound.

5. The method of any preceding or subsequent embodiment/feature/aspect, wherein the enzyme is a hydrolase.

6. The method of any preceding or subsequent embodiment/feature/aspect, further comprising bleaching the pulp after formation of the pulp and before adding the anionic charged compound and enzyme to the pulp.

7. A process for producing commodity pulp comprising:

forming the cellulose particles into pulp;

adding at least one anionic surfactant and at least one enzyme to the pulp to provide a treated pulp;

mechanically dewatering the treated pulp to provide a mechanically dewatered pulp; and

the mechanically dewatered pulp is thermally dried to form a commodity pulp.

8. The method of any preceding or subsequent embodiment/feature/aspect, wherein at least a portion of the addition of the enzyme to the pulp occurs prior to the addition of the anionic surfactant to the pulp.

9. The method of any preceding or subsequent embodiment/feature/aspect, wherein about 80% -100% by weight of the addition of the enzyme to the pulp occurs prior to the addition of the anionic surfactant to the pulp.

10. The method of any preceding or subsequent embodiment/feature/aspect, further comprising bleaching the pulp after formation of the pulp and before adding the anionic surfactant and enzyme to the pulp.

11. The method of any preceding or subsequent embodiment/feature/aspect, wherein the anionic surfactant is a sulfate surfactant, a sulfonate surfactant, a sulfosuccinate surfactant, or any combination thereof.

12. The method of any preceding or subsequent embodiment/feature/aspect, wherein the anionic surfactant is an alcohol sulfate, alcohol alkoxy sulfate, sulfonate, dialkyl sulfosuccinate, sulfosuccinate with an ethoxylated alcohol, or a soluble or dispersible salt thereof, or any combination thereof.

13. The method of any preceding or subsequent embodiment/feature/aspect, wherein the enzyme is a cellulase, hemicellulase, pectinase, cellobiase, xylanase, mannanase, beta-glucanase, carboxymethylcellulase, amylase, glucosidase, galactosidase, laccase, or any combination thereof.

14. The method of any preceding or subsequent embodiment/feature/aspect, wherein the forming provides kraft pulp, sulfite pulp, fluff pulp, dissolving pulp, bleached chemithermomechanical pulp, or any combination thereof.

15. The method of any preceding or subsequent embodiment/feature/aspect, further comprising bleaching the pulp after formation of the pulp and before adding the anionic surfactant and enzyme to the pulp.

16. The method of any preceding or following embodiment/feature/aspect, wherein the mechanical dewatering comprises screening and pressing of the pulp, wherein discharged white water from the screening is combined with fresh pulp and pumped with a fan pump to a headbox for screening, wherein the enzyme is fed into the combined fresh pulp and white water prior to entering the fan pump and the anionic surfactant is fed into the combined fresh pulp and white water after exiting the fan pump and prior to reaching the headbox.

17. The method of any preceding or subsequent embodiment/feature/aspect, wherein the anionic surfactant and enzyme are added to the pulp at a ratio of from about 10,000:1 to about 1: 10.

18. The method of any preceding or subsequent embodiment/feature/aspect, wherein the anionic surfactant is added to the pulp in an amount of from about 0.1 lb./ton dry fiber to about 10 lb./ton dry fiber, and the enzyme is added to the pulp in an amount of from about 0.001 lb./ton dry fiber to about 2 lb./ton dry fiber.

19. The method of any preceding or following embodiment/feature/aspect, further comprising containerizing the commodity pulp to form a containerized commodity pulp.

20. The method of any preceding or subsequent embodiment/feature/aspect, wherein the cellulose particles are hardwood chips, softwood chips, recycled paper fibers, or any combination thereof.

21. The method of any preceding or following embodiment/feature/aspect, wherein the treating the pulp with the at least one anionic surfactant and at least one enzyme combination prior to dewatering in the production of commodity pulp is effective to provide at least one of:

(i) pulp free drainage (g/90 sec) increased to the following values: which is at least 7.5% times greater than the free drainage value obtained without any treatment in the pulp;

(ii) Pulp free drainage increased to the following values: at least about 3% greater than the free drainage value obtained if the anionic surfactant is used alone in the pulp (without the use of the enzyme);

(iii) pulp free drainage increased to the following values: at least about 10% greater than a free drainage value calculated as the sum of the free drainage enhancement amounts obtained from the use of the anionic surfactant and enzyme separately and individually in the pulp; and

(iv) pulp retention value (WRV) reduced to the following value: which is at least about 10% less than the WRV obtained if the anionically charged compound was used separately and solely in the pulp (without the use of the enzyme).

22. The method of any preceding or following embodiment/feature/aspect, wherein the treating is effective to increase the obtained free drainage to a value of: which is at least 5 times greater than the free drainage value obtained without any treatment of the pulp.

23. The method of any preceding or following embodiment/feature/aspect, wherein the treating is effective to increase the obtained free drainage to a value of: which is about 60% to about 200% greater than the free drainage value obtained if the anionic surfactant is used alone in the pulp.

24. A commodity pulp produced by the method of any preceding or following embodiment/feature/aspect, comprising the anionic charged compound and the enzyme.

25. A commodity pulp manufactured by the method of any preceding or following embodiment/feature/aspect, comprising the anionic surfactant and the enzyme.

26. A system for producing commodity pulp, comprising:

a cellulose particle supplier;

at least one pulp forming unit for forming pulp from the cellulose particles;

at least one feeding device for feeding at least one anionically charged compound to the pulp;

at least one feeding device for feeding at least one enzyme to the pulp to provide a treated pulp after addition of both the anionic charged compound and the enzyme;

a mechanical dewatering device for mechanically removing water from the treated pulp to provide a mechanically dewatered pulp; and

a thermal drying device for thermally removing water from the mechanically dewatered pulp to provide a commodity pulp.

27. The system of any preceding or subsequent embodiment/feature/aspect, wherein the at least one feeding device for feeding an anionic charged compound feeds an anionic surfactant and the at least one feeding device for feeding an enzyme feeds a hydrolase.

28. The system of any preceding or subsequent embodiment/feature/aspect, wherein the pulp forming unit is a digester capable of receiving at least one chemical for digesting the cellulose particles.

29. The system of any preceding or following embodiment/feature/aspect, wherein the mechanical dewatering device comprises a screen section and a press section, wherein discharge white water from the screen section is combinable with fresh pulp and pumpable with a fan pump to a headbox of the mechanical dewatering device, wherein the at least one feed device for the enzyme is capable of feeding the enzyme into the combined fresh pulp and white water prior to entering the fan pump, and the at least one feed device for the anionically charged compound is capable of feeding the anionically charged compound into the combined fresh pulp and white water after exiting the fan pump and prior to reaching the headbox.

30. The system of any preceding or subsequent embodiment/feature/aspect, further comprising a unit for bleaching the pulp after the pulp forming unit and before adding the anionic charged compound and enzyme to the pulp with the respective feeding devices.

31. The system of any preceding or following embodiment/feature/aspect, wherein first and second feed devices are capable of introducing respective first and second amounts of the anionically charged compound and enzyme to the pulp withdrawn from the pulp forming unit to provide at least one of:

(i) pulp free drainage (g/90 sec) increased to the following values: which is at least 7.5% times greater than the free drainage value obtained without any treatment in the pulp;

(ii) pulp free drainage increased to the following values: at least about 3% greater than the free drainage value obtained if the anionic charged compound is used alone in the pulp (without the use of the enzyme);

(iii) pulp free drainage increased to the following values: at least about 10% greater than a free drainage value calculated as the sum of the free drainage enhancement amounts obtained from using the anionic charged compound and enzyme separately and individually in the pulp; and

(iv) pulp retention value (WRV) reduced to the following value: which is at least about 10% less than the WRV obtained if the anionically charged compound was used alone in the pulp (without the use of the enzyme).

The invention may comprise any combination of these various features or embodiments above and/or below as set forth in sentences and/or paragraphs. Any combination of features disclosed herein is considered a part of the present invention and no limitation with respect to the combinable features is intended.

Applicants specifically incorporate the entire contents of all cited references into this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited, when such ranges are defined.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims and their equivalents.

Claims (31)

1. A process for producing commodity pulp comprising:

forming the cellulose particles into pulp;

adding at least one anionic charged compound and at least one enzyme to the pulp to provide a treated pulp;

mechanically dewatering the treated pulp to provide a mechanically dewatered pulp; and

the mechanically dewatered pulp is thermally dried to form a commodity pulp.

2. The method of claim 1, wherein at least a portion of the addition of the enzyme to the pulp occurs prior to the addition of the anionic charged compound to the pulp.

3. The method of claim 1, wherein about 80% -100% by weight of said addition of said enzyme to said pulp occurs prior to said addition of said anionically charged compound to said pulp.

4. The method of claim 1, wherein the anionic charged compound is an organic anionic charged compound.

5. The method of claim 1, wherein the enzyme is a hydrolase.

6. The method of claim 1, further comprising bleaching the pulp after the pulp is formed and before adding the anionic charged compound and enzyme to the pulp.

7. A process for producing commodity pulp comprising:

forming the cellulose particles into pulp;

adding at least one anionic surfactant and at least one enzyme to the pulp to provide a treated pulp;

mechanically dewatering the treated pulp to provide a mechanically dewatered pulp; and

the mechanically dewatered pulp is thermally dried to form a commodity pulp.

8. The method of claim 7, wherein at least a portion of the addition of the enzyme to the pulp occurs prior to the addition of the anionic surfactant to the pulp.

9. The method of claim 7, wherein about 80% -100% by weight of said addition of said enzyme to said pulp occurs prior to said addition of said anionic surfactant to said pulp.

10. The method of claim 7, further comprising bleaching the pulp after the pulp is formed and before adding the anionic surfactant and enzyme to the pulp.

11. The method of claim 7, wherein the anionic surfactant is a sulfate surfactant, a sulfonate surfactant, a sulfosuccinate surfactant, or any combination thereof.

12. The method of claim 7, wherein the anionic surfactant is an alcohol sulfate, alcohol alkoxy sulfate, sulfonate, dialkyl sulfosuccinate, sulfosuccinate with an ethoxylated alcohol, or a soluble or dispersible salt thereof, or any combination thereof.

13. The method of claim 7, wherein the enzyme is a cellulase, a hemicellulase, a pectinase, a cellobiase, a xylanase, a mannanase, a beta-glucanase, a carboxymethylcellulase, an amylase, a glucosidase, a galactosidase, a laccase, or any combination thereof.

14. The method of claim 7, wherein the forming provides kraft pulp, sulfite pulp, fluff pulp, dissolving pulp, bleached chemi-thermomechanical pulp, or any combination thereof.

15. The method of claim 7, further comprising bleaching the pulp after the pulp is formed and before adding the anionic surfactant and enzyme to the pulp.

16. The method of claim 7, wherein the mechanical dewatering comprises screening and pressing of the pulp, wherein discharged white water from the screening is combined with fresh pulp and pumped with a fan pump to a headbox for screening, wherein the enzyme is fed into the combined fresh pulp and white water prior to entering the fan pump and the anionic surfactant is fed into the combined fresh pulp and white water after exiting the fan pump and prior to reaching the headbox.

17. The method of claim 7, wherein the anionic surfactant and enzyme are added to the pulp in a ratio of about 10,000:1 to about 1: 10.

18. The method of claim 7, wherein the anionic surfactant is added to the pulp in an amount of about 0.1 lb./ton dry fiber to about 10 lb./ton dry fiber, and the enzyme is added to the pulp in an amount of about 0.001 lb./ton dry fiber to about 2 lb./ton dry fiber.

19. The method of claim 7, further comprising containerizing the commodity pulp to form a containerized commodity pulp.

20. The method of claim 7, wherein the cellulose particles are hardwood chips, softwood chips, recycled paper fibers, or any combination thereof.

21. The method of claim 7, wherein treating the pulp with the at least one anionic surfactant and at least one enzyme combination prior to dewatering in the production of commodity pulp is effective to provide at least one of:

(i) pulp free drainage (g/90 sec) increased to the following values: which is at least 7.5% times greater than the free drainage value obtained without any treatment in the pulp;

(ii) Pulp free drainage increased to the following values: at least about 3% greater than the free drainage value obtained if the anionic surfactant is used alone in the pulp (without the use of the enzyme);

(iii) pulp free drainage increased to the following values: at least about 10% greater than a free drainage value calculated as the sum of the free drainage enhancement amounts obtained from the use of the anionic surfactant and enzyme separately and individually in the pulp; and

(iv) pulp retention value (WRV) reduced to the following value: which is at least about 10% less than the WRV obtained if the anionic surfactant is used alone in the pulp (without the use of the enzyme).

22. The method of claim 7, wherein the treatment is effective to increase the obtained free drainage to a value of: which is at least 5 times greater than the free drainage value obtained without any treatment of the pulp.

23. The method of claim 7, wherein the treatment is effective to increase the obtained free drainage to a value of: which is about 60% to about 200% greater than the free drainage value obtained if the anionic surfactant is used alone in the pulp.

24. A commodity pulp produced by the method of claim 1, comprising the anionic charged compound and the enzyme.

25. A commodity pulp produced by the method of claim 7, comprising the anionic surfactant and the enzyme.

26. A system for producing commodity pulp, comprising:

a cellulose particle supplier;

at least one pulp forming unit for forming pulp from the cellulose particles;

at least one feeding device for feeding at least one anionically charged compound to the pulp;

at least one feeding device for feeding at least one enzyme to the pulp to provide a treated pulp after addition of both the anionic charged compound and the enzyme;

a mechanical dewatering device for mechanically removing water from the treated pulp to provide a mechanically dewatered pulp; and

a thermal drying device for thermally removing water from the mechanically dewatered pulp to provide a commodity pulp.

27. The system of claim 26, wherein the at least one feed device for feeding anionic charged compounds feeds anionic surfactants and the at least one feed device for feeding enzymes feeds hydrolases.

28. The system of claim 26, wherein the pulp forming unit is a digester capable of receiving at least one chemical for digesting the cellulose particles.

29. The system of claim 26, wherein the mechanical dewatering device comprises a screen section and a press section, wherein discharged white water from the screen section can be combined with fresh pulp and pumped to a headbox of the mechanical dewatering device with a fan pump, wherein the at least one feed device for the enzyme can feed the enzyme into the combined fresh pulp and white water prior to entering the fan pump, and the at least one feed device for the anionic charging compound can feed the anionic charging compound into the combined fresh pulp and white water after exiting the fan pump and prior to reaching the headbox.

30. The system of claim 26, further comprising a bleaching unit for bleaching the pulp after the pulp forming unit and before adding the anionic charged compound and enzyme to the pulp with the respective feeding devices.

31. The system of claim 26, wherein first and second feed devices are capable of introducing respective first and second amounts of the anionically charged compound and enzyme to the pulp withdrawn from the pulp forming unit to provide at least one of:

(i) Pulp free drainage (g/90 sec) increased to the following values: which is at least 7.5% times greater than the free drainage value obtained without any treatment in the pulp;

(ii) pulp free drainage increased to the following values: at least about 3% greater than the free drainage value obtained if the anionic charged compound is used alone in the pulp (without the use of the enzyme);

(iii) pulp free drainage increased to the following values: at least about 10% greater than a free drainage value calculated as the sum of the free drainage enhancement amounts obtained from using the anionic charged compound and enzyme separately and individually in the pulp; and

(iv) pulp retention value (WRV) reduced to the following value: which is at least about 10% less than the WRV obtained if the anionically charged compound was used alone in the pulp (without the use of the enzyme).

Images