• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    METHOD AND SYSTEM FOR PROCESSING PULP USING COLD CAUSTIC EXTRACTION WITH REUSE OF ALKALINE FILTRATE. A method for processing pulp includes a cold caustic extraction stage, in which the spent cold caustic solution and the spent liquid used to wash the extracted pulp are concentrated by an evaporation system. The concentrated liquid can be used as part of the neutralization and cooking liquor in the pulp process, leading to increased efficiency without significant reduction in pulp quality. A highly concentrated filtrate from the cold caustic extraction stage can help to reduce the deposition of hemicellulose in the wood fiber during the cooking step.
    公开号:BR112012028241B1
    申请号:R112012028241-7
    申请日:2010-08-18
    公开日:2020-11-10
    发明作者:Marcelo Moreira Leite
    申请人:Bahia Specialty Cellulose Sa；
    IPC主号:
    专利说明:

    BACKGROUND OF THE INVENTION 1) Field of the Invention
    [001] The field of the invention generally refers to pulp processing and, more specifically, to an improved method and system for the treatment of cold caustic extraction effluents in relation to a chemical Kraft pulping process. 2) Background
    [002] A pulp of wood and plant materials has a large number of commercial uses. Although one of the most common uses is in the manufacture of paper, pulp can also be used for the production of various other products including rayon and other synthetic materials, as well as cellulose acetate and cellulose esters, which are used, for example, in the manufacture of filter tow, cloth, packaging films and explosives.
    [003] Various chemical and mechanical methods exist for processing wood and plant materials, in order to manufacture pulp and paper. The basic processing steps include the preparation of the raw material (for example, removal of bark rings and splintering), separation of the wood fibers by mechanical or chemical means (for example, milling, refinement or cooking) for separation of the wood. lignin and cellulose extracts from wood fibers, removal of coloring agents by bleaching, and formation of the resulting processed pulp on paper or other products. In addition to and in relation to pulp and paper making, paper mills also typically have facilities for the production and recovery of chemical agents, collection and processing of by-products for energy production, and removal and treatment of waste for minimizing environmental impact.
    [004] A "pulp formation" generally refers to the process for obtaining fiber separation. Wood and other plant materials comprise cellulose, hemicellulose, lignin and other minor components. Lignin is a network of interpolated polymers between individual fibers and functions as an intercellular adhesive for cementing individual wood fibers together. During the pulping process, the lignin macromolecules are fragmented, thereby releasing the individual cellulosic fibers and dissolving impurities that can cause discoloration and future disintegration of the paper or other final product.
    [005] The Kraft process is a commonly used pulping process. The paper produced from the Kraft pulping process can be used, for example, to make a bleached cardboard box and a coated box used in the packaging industry. A conventional Kraft process treats wood with an aqueous mixture of sodium hydroxide and sodium sulfide, known as "white liquor". The treatment breaks the link between lignin and cellulose, and degrades most of the lignin and a portion of hemicellulose macromolecules into fragments that are soluble in strongly basic solutions. This process of releasing lignin from the surrounding cellulose is known as delignification. The soluble portion thereafter is separated from the cellulose pulp.
    [006] Figure 1 shows a flow chart of a conventional Kraft 100 process. Process 100 involves feeding wood chips (or other raw materials containing organic pulp) 118 and alkaline solutions in a high pressure reaction vessel called a digester to effect delignification, in what is referred to as a “cooking” stage 121. The wood chips are combined with white liquors 111, which can be generated from downstream processes or provided from a separate source . Delignification can take several hours, and the degree of delignification is expressed as the dimensionless “H factor”, which is generally defined so that an hour-long cook at 100 ° C is equivalent to an H factor of 1. Due to the high temperature, the reaction vessel is often pressurized due to the introduction of steam. Towards the end of the cooking step, the reaction vessel is reduced to atmospheric pressure, thereby releasing steam and volatiles.
    [007] The white liquor used in cooking can be, for example, a caustic solution containing sodium hydroxide (NaOH) and sodium sulfide (Na2S). The property of white liquor is often expressed in terms of effective alkali (“EA”) and sulfidity. The effective alkali concentration can be calculated as the weight of sodium hydroxide plus half the weight of sodium sulfide, and represents the equivalent weight of sodium hydroxide per liter of liquor, expressed in grams per liter. The effective alkali charge such as sodium hydroxide represents the equivalent weight of sodium hydroxide per dry weight in a wood oven, expressed as a percentage. Sulfidity is the ratio of half the weight of sodium hydroxide to the sum of the weight of sodium hydroxide and half of the weight of sodium sulfide, expressed as a percentage.
    [008] After cooking, a solid brown cellulosic pulp, also known as “brown raw material” is released from the digester used in cooking stage 121, and then is sieved and washed in the washing and sieving process 122. The sieving separates the pulp from shards (bundles of wood fibers), knots (uncooked chips), dirt and other debris. The materials separated from the pulp are sometimes referred to as the “waste” and the pulp as the “accepted”. Multi-stage cascade operations are often used to reduce the amount of cellulosic fibers in the tailing stream while maintaining high purity in the acceptance stream. Additional fiber recovery can be achieved through a downstream refiner or reprocessing strained parts and knots in the digester.
    [009] The brown raw material can then be subjected to several stages of washing in series, for the separation of spent cooking liquors and dissolved materials from cellulose fibers. The spent cooking liquor 112 from the digester employed in cooking stage 121 and the liquor 113 collected from the washing and sieving process 122 are commonly referred to as a "black liquor" because of their coloring. The black liquor usually contains fragments of lignin, fragmented and inorganic hemicellulose carbohydrates. The black liquor can be used in addition to the white liquor in the cooking step, as illustrated, for example, in figure 1 by the arrow representing the black liquor 113 produced in the washing and sieving process 122 and transferred to the cooking stage 121. The liquor black 135 from an accumulator tank (not shown in figure 1) can also be fed to the digester as part of cooking stage 121, if necessary, to obtain the appropriate alkaline concentration or for other similar purposes.
    [010] The clean brown raw material pulp 131 from the washing and screening process 122 then can be mixed with white liquor 114 and fed into a reaction vessel for additional removal of dissolved materials, such as hemicellulose and low-grade cellulose. molecular weight. An example separation method is the so-called cold caustic extraction method (“CCE”), and is represented by the reaction stage of CCE 123 in figure 1. The temperature at which the extraction is carried out can vary, but typically , is less than 60 ° C.
    [011] The purified pulp 132 of the reactor used in the CCE 123 reaction stage is then separated from the spent cold caustic solution and dissolved hemicellulose, and washed several times in a second washing and separation unit in a washing stage. of CCE 124. The resulting purified brown pulp 133 with a relatively high content of alpha cellulose, still containing some lignin, continues on to a downstream bleaching unit for further delignification. In some pulp production processes, bleaching is carried out before the CCE 123 reaction stage and the CCE 124 washing stage.
    [012] It is desirable in various applications, such as in the manufacture of synthetic materials or pharmaceutical products, to have a pulp of very high purity or quality. The quality of the pulp can be assessed by several parameters. For example, the percentage of alpha cellulose content expresses the relative purity of the processed pulp. The degrees of delignification and cellulose degradation are measured by the Kappa Number (“KN”) and the viscosity of the pulp, respectively. Higher pulp viscosity indicates a longer cellulose chain length and less degradation. The pulp solubility in 18% by weight aqueous sodium hydroxide solutions (“S18”) provides an estimate of the amount of residual hemicellulose. A pulp solubility in 10% by weight aqueous sodium hydroxide solution (“S10”) provides an indication of the total amounts of soluble matter in basic solutions, which includes the sum of hemicellulose and degraded cellulose. Finally, the difference between S10 and S18 determines the amount of cellulose degraded.
    [013] In a conventional process, filtrate 116 also referred to as the CCE alkali filtrate, from the CCE washing and separation stage 124 comprises the spent cold caustic solution and the spent washing liquid from the stage washing and separating 124. This filtrate 116 often contains substantial amounts of high molecular weight hemicellulose. When a filtrate with a high hemicellulose content is used as part of the cooking liquor in the cooking stage digester 121, the hemicellulose may precipitate out of the solution and deposit on the cellulosic fibers. This can prevent a high quality pulp from being obtained. On the other hand, certain applications - such as high quality yarn or synthetic fabrics, materials for liquid crystal displays, products made with acetate derivatives, viscose products (such as tire cord and special fibers), filter tow segments used in cigarettes, and certain food and pharmaceutical applications - want pulps containing a minimum amount of redeposited hemicelluloses and alpha cellulose content.
    [014] Some of the alkaline filtrate from CCE 116 can be reused in cooking stage 121, while the remainder is sent to recovery area 134 in order to control the risk of redeposition of hemicelluloses in cooking stage 121. In recovery area 134, the diverted alkaline filtrate of CCE 116 can be combined with an excess black liquor, concentrated and burned in a recovery boiler for consumption of organics and recovery of inorganic salts, or, even, it was taken to another line pulping, or a combination of both. A new source of alkali may then be required to replace the CCE filtrate and the black liquor sent to recovery area 134, in order to maintain an appropriate alkali balance in cooking stage 121. The recovery process and the provision of a new source of alkali tend to result in increased production costs.
    [015] There is a need for a pulp processing method and system that results in a dissolved pulp with a high alpha cellulose content. There is still a need for a pulp processing method and system that provide increased efficiency and allow efficient use of the CCE filtrate while minimizing hemicellulose deposition during cooking. SUMMARY OF THE INVENTION
    [016] In one aspect, an improved method and system for pulp production involves, among other things, washing purified pulp produced from a cold caustic extraction process, collecting an alkaline filtrate resulting therefrom, concentration of the alkaline filtrate, for example, by evaporation, and the use of at least a portion of the concentrated alkaline filtrate in an upstream cooking process.
    [017] According to one or more modalities, a method and a system for pulp production using cold caustic extraction in conjunction with a Kraft process includes the steps of delignifying materials containing organic pulp in a digester, the treatment of a material resulting brown raw material for the production of semipurified pulp, the extraction of semipurified pulp with a caustic solution for the production of a purified pulp and a solution containing hemicellulose, the separation of the solution containing hemicellulose from the purified pulp, the washing of the purified pulp and the collection of an resulting alkaline filtrate, the concentration of the alkaline filtrate and the use of at least a portion of the alkaline filtrate concentrated in the digester. The concentrated alkaline filtrate can gradually replace a different cooking liquor that is initially used to start the cooking process, thereby resulting in increased efficiency.
    [018] In certain embodiments, an alkaline filtrate is concentrated to form a solution containing, for example, 90 grams or more per liter of effective alkali such as sodium hydroxide. By using concentrated alkaline filtrate as part of the cooking liquor, the purity of the brown raw material and the resulting purified pulp can be improved.
    [019] Additional modalities, alternatives and variations are also described here or illustrated in the associated figures. BRIEF DESCRIPTION OF THE DRAWINGS
    [020] Figure 1 is a general process flow chart of a conventional pre-hydrolysis Kraft pulp process used in relation to pulp production, as known in the art.
    [021] Figure 2 is a process flow chart of a pulp production process according to a modality, as shown here.
    [022] Figure 3 is a conceptual diagram of a system and related process for cold caustic post-extraction with evaporation according to the general principles illustrated in figure 2.
    [023] Figure 4 is a diagram of a conventional system and an evaporation process, as they can be used in relation to, among other things, cold caustic extraction.
    [024] Figure 5 is a diagram of a system and a related process for evaporating filtrate from a cold caustic extraction according to the general principles illustrated in figures 2 and 3. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
    [025] According to one or more modalities, a method and system for pulp processing involves combining a first caustic solution, such as white liquor, with an amount of wood or other organic material containing raw pulp in an appropriate tank or vessel (a digester) for cooking at an appropriate temperature, for example, between 130 and 180 ° C, for the production of a brown raw material. Washing and sifting the brown raw material results in a semi-purified pulp, as well as derivatives (such as a black liquor) that are fed back to the digester. The semi-purified pulp can be extracted with another caustic solution (which, again, can be white liquor) at a suitable temperature, for example, below 60 ° C, for the production of a purified pulp. Through additional washing, a solution containing hemicellulose can be separated from the purified pulp, resulting in another caustic solution in the form of an alkaline filtrate that can be collected and stored separately. This alkaline filtrate can be concentrated, for example, by evaporation or other means, and used by itself or in combination with the first caustic solution in the digester, for the treatment of organic materials and the resumption of the cycle.
    [026] According to an aspect of one or more modalities, wood chips or other organics containing pulp are reacted with a caustic solution in a reaction vessel. At the end of the reaction, the reaction mixture contains released cellulosic fibers. These fibers are further extracted with a second caustic solution to dissolve hemicellulose. The caustic solution spent together with the dissolved hemicellulose is separated from the extracted pulp, and the pulp is subjected to an additional wash to remove residual caustic solution and hemicellulose. The washing liquids and spent caustic solution containing hemicellulose are combined and concentrated to form a concentrated CCE filtrate. The concentrated CCE filtrate can then be used singly or in combination with another caustic solution for treating wood in the reaction vessel.
    [027] All the steps outlined above can be performed with other traditional equipment. Following the steps outlined above, according to the specification, can result in a concentrated CCE filtrate that has an effective alkali concentration comparable to that of a white liquor commonly used for cooking.
    [028] A process according to a modality is illustrated in figure 2. Process 200 begins with a cooking stage 221 in which, similar to the conventional Kraft process, wood chips or other organic materials containing pulp 218 are fed to a digester capable of withstanding high pressure. The digester can be of any suitable volume, such as, for example, approximately 360 cubic meters. In a typical industrial setting, a plurality of digesters can be placed in parallel, with different digesters operating at different stages of the pulp production process.
    [029] The particular choice of type of wood or other plant or organic materials used in digesters may depend on the desired end products. For example, soft woods, such as pine, spruce and spruce, can be used for some derivatization processes to obtain products with high viscosity, such as cellulose ethers (which can be used, for example, as additives in food , paints, oil recovery fluids or sludges, paper, cosmetics, pharmaceuticals, adhesives, printing, agriculture, ceramics, textiles, detergents and building materials). Hard woods, such as eucalyptus and acacia, may be preferred for those applications that do not require a pulp with very high viscosity.
    [030] In one embodiment, the digester is heated during cooking stage 221 to a first predetermined temperature with steam or other appropriate means. This predetermined temperature can be between 110 and 130 ° C and, more specifically, for example, can be 120 ° C. Heating in this particular example is carried out for a period of time between 15 and 60 minutes (for example, 30 minutes), although other heating times may be used, depending on the particularities of the equipment and the nature of the organic materials being heated.
    [031] The digester is preferably then further heated by steam or other means to a second temperature above the first predetermined temperature for a prehydrolysis stage. This second pre-hydrolysis temperature is preferably around 165 ° C, although, again, the precise temperature may depend on several variables, including equipment and organic materials. Heating for prehydrolysis can be done for a period of 30 to 120 minutes (for example, for 60 minutes), although again, the heating time may vary as needed. Once the prehydrolysis temperature is reached, the digester is maintained at that temperature for an appropriate period of time, for example, 35 to 45 minutes, or any other time sufficient to complete the prehydrolysis.
    [032] In a preferred embodiment, a neutralization solution 210 is added to the digester as part of cooking stage 221. The neutralization solution 210 can be composed of a freshly prepared white liquor followed by black liquor, or it can be composed of a filtrate of CCE followed by black liquor. A white liquor can take the form, for example, of a mixture of sodium hydroxide and sodium sulfide. In a preferred embodiment, the white liquor has between 85 and 150 grams per liter of effective alkali as sodium hydroxide (NaOH), more preferably, between 95 and 125 grams per liter of effective alkali as sodium hydroxide, and, most preferably , between 100 and 110 grams per liter of effective alkali such as sodium hydroxide. The sulfidity of the white liquor can range from 10% to 40%, preferably between 15% and 35%, and most preferably between 20 and 30%.
    [033] The effective NaOH concentration in black liquor can be between 10 and 50 grams per liter, although it can vary according to the particular process. In one embodiment, the neutralization solution 210 comprises a white liquor and a black liquor, with an effective alkali concentration of 85 to 150 grams of sodium hydroxide per liter for white liquor and an effective alkali concentration of 20 to 50 grams of sodium hydroxide per liter for black liquor. In a preferred embodiment, the neutralization solution 210 comprising white liquor and black liquor has an effective alkali concentration, respectively, between 95 and 125 grams per liter and, 30 and 35 grams per liter, and, more preferably, has an effective concentration between 100 and 110 grams per liter and, 38 and 45 grams per liter, respectively. The neutralization solution 210 can have an effective alkali concentration of 38 to 48 grams of NaOH per liter for the combined liquors.
    [034] The neutralization solution 210 can be added to the digester in one portion or else it can be added to the digester in several portions. In one embodiment, the neutralization solution 210 comprising a white liquor and a black liquor is added in two portions, whereby the white liquor is first provided to the digester followed by the addition of the black liquor. In one embodiment, the neutralization solution 210 is added at a temperature between 130 and 160 ° C, and, more preferably, between 140 and 150 ° C. The addition can be done for a period of 15 to 60 minutes, preferably for a period of 30 minutes. In a preferred embodiment, the neutralization solution 210 is added in two portions, each for a period of 15 minutes, at a temperature between 140 and 150 ° C.
    [035] A first caustic solution 211 can then replace neutralization solution 210 and is used for cooking wood in the digester. The first caustic solution 211 may have the same composition as that of neutralization solution 210, or it may have a different composition. The preferred range and range of sodium hydroxide and sodium sulfide in the first caustic solution 211 then are the same as those for neutralization solution 210, and are well known to someone skilled in the art.
    [036] The digester can be heated to the cooking temperature with steam or other means. The cooking temperature can be in the range between 140 and 180 ° C, and is preferably in the range between 145 and 160 ° C. The warm-up can be for a period of 10 to 30 minutes or another suitable period. The digester is kept at the cooking temperature for a period suitable for the cooking process, such as between 15 and 120 minutes. The temperature range and cooking time are chosen for the target H factor, which is preferably in the range between 130 and 250.
    [037] The preferred techniques for neutralization and cooking are described in copending US Patent Application Serial No. 12 / 789,307 (Legal Protocol No. 161551-003) filed concurrently with it and entitled “Method and System for High Alpha Dissolving Pulp Production ”, assigned to the assignee of the present invention, and incorporated here by reference, as if fully established here.
    [038] As a result of cooking stage 221, a brown raw material 212 is produced. The brown raw material 212 is provided for a washing and screening process 222, similar to a conventional Kraft procedure, whereby the brown raw material 212 is sieved through the use of different types of sieves and sieves and centrifugal cleaning. The brown raw material 212 is then washed with a washer in the 222 washing and screening process. The washer can be of any commercial type, including horizontal belt washers, rotary drum washers, vacuum filters, wash presses, filters with compaction deflector, atmospheric diffusers and pressure diffusers. The washing unit can use a countercurrent flow between the stages, so that the pulp moves in the opposite direction to the washing waters. In one embodiment, pressurized water is used for washing the brown raw material 212. In another embodiment, a dilute caustic solution is used for washing the brown raw material 212. The diluted caustic solution can have, for example, a effective alkali concentration of less than 5 grams of NaOH per liter, more preferably, less than 1 gram of NaOH per liter. The spent wash liquor is collected and used as black liquor 213 elsewhere in process 200. In one embodiment, black liquor 213 is used as part of the cooking liquor or other caustic solution 211 provided to the digester at the cooking stage 221.
    [039] The semipurified pulp from the washing and screening process 222 is then pumped as a slurry to a reactor, which is used in the cold caustic extraction (“CCE”) 223 stage, again similar to the conventional method, wherein the semipurified pulp is mixed with a second caustic solution 214 (which may be the same or different from the first caustic solution 211) to effect an additional separation of hemicellulose from the desired cellulosic fibers. A cold caustic extraction is a process well known in the art. Examples of cold caustic treatment systems are described in more detail, for example, in Ali et al., US Patent Application Publication No. 2004/0020854, and Svenson et al., US Patent Application Publication No. 2005/023291, both being incorporated in this way as a reference, as if fully established here.
    [040] The extraction of hemicellulose in the CCE 223 extraction process is carried out at an appropriate temperature, typically between 15 and 50 ° C, and preferably around 30 ° C. The pH of the pulp is typically above 13 with an effective alkali between 60 and 90 grams of NaOH per liter. The pulp is infused in the cold caustic solution 214 for an amount of time sufficient to obtain the desired degree of diffusion of the hemicellulose in the solution. An example waiting time for an extraction at 30 ° C at a pH of 13 is 30 minutes. A cold caustic extraction can generally result in a purified pulp with an alpha cellulose content in the range of 92 to 96 percent, although historically it has been quite difficult to achieve purities at the upper end of that scale or beyond, particularly while maintaining other desirable characteristics pulp (such as viscosity level). It has also been difficult to achieve high purities while maintaining high process efficiency.
    [041] The caustic solution 214 used in the mixing and extraction procedures of the CCE 223 extraction process can comprise quick preparations of sodium hydroxide solutions recovered from the downstream process or by-products of a pulp or paper mill operation, for example , white liquor with caustic hemi, white oxidized liquor and the like. Other basic solutions, such as ammonium hydroxide and potassium hydroxide, can also be used.
    [042] The caustic solution 214 used in the CCE 223 extraction process may contain an appropriate hydroxide concentration; for example, the caustic solution 214 may contain from 3% to 50% by weight of hydroxide concentration, and, more preferably, between 6% and 18% by weight of hydroxide concentration. The extraction can be carried out in any suitable pulp consistency, such as around 2% to 50% by weight, but preferably around 5% to 10% by weight. In this context, the term “consistency” refers to the concentration of cellulosic fibers in the extraction mixture.
    [043] After the desired waiting time, the pulp is separated from the cold caustic solution spent in a subsequent washing process 224. The spent cold caustic solution contains extracted hemicellulose. The pulp is washed in the CCE washing unit. Sample washers include horizontal belt washers, rotary drum washers, vacuum filters, washing presses, compaction deflector filters, atmospheric diffusers and pressure diffusers. The washing liquid can comprise, for example, pure water or a caustic solution diluted with an effective alkali concentration, for example, below 1 gram of NaOH per liter. The spent washing liquid is collected in a conventional manner and can be combined with a spent cold caustic solution to form another caustic solution 216, which, in one aspect, comprises an alkaline filtrate resulting from the washing process 224. The pulp extracted and washed 233, while it is transported to the next stage for bleaching.
    [044] The third caustic solution 216 is preferably provided for a concentration process 225, and can be fed, for example, to an evaporation system for concentration. A typical evaporation system can contain several units or effects installed in series. The liquid moves through each effect and becomes more concentrated at the effect's output. A vacuum can be applied to facilitate evaporation and the concentration of solutions.
    [045] In relation to the concentration process 225, a weak black liquor 243 can be concentrated in a strong black liquor 244, for example, by evaporation, using one or more effects in a sequential arrangement, gradually increasing the concentration of the liquor faint black 243 during the process. The strong black liquor 244 can be stored in an accumulation tank and used in the recovery area (recovery boiler) or for other purposes, thus increasing efficiency through the reuse or recycling of outgoing by-products.
    [046] The number of effects used for evaporation depends, in part, on the desired concentration level, the capacity of the plant and other factors. In one embodiment, the evaporation equipment for the concentration stage 225 comprises six effects capable of processing, for example, 740 tons of liquor per hour. The effects may, but need not be, of the same type used for the concentration of black liquor from the cooking stage 221. It is typical, for example, to use a series of effects to concentrate the weak black liquor left from the cooking stage. and store it in a maintenance tank, where it can be recycled for use in the cooking process or sent to other processes for different purposes. Usually, an excess of black liquor is produced, and the excess black liquor is burned in an incinerator for power generation.
    [047] In a preferred embodiment (as shown in figure 3), the concentration of alkaline extraction solution 316 from the CCE 224 wash stage occurs in two of six effects (in this example, the fifth effect 327 and the sixth effect 328) under reduced pressure, to ensure a concentrated solution 330, i.e., a concentrated CCE alkaline filtrate. The concentration of the weak black liquor from cooking stage 221 in a concentrated black liquor occurs in four of the six effects at a higher pressure. In this example, weak black liquor 313 is introduced in one effect (in this example, the fourth effect 326) and, after a preliminary concentration, is pumped to an additional concentration in other downstream effects 329. The concentration of the alkaline extraction solution 316 from washing stage 224, which can be a combination of spent washing liquid 314 and spent cold caustic solution 315, can be provided in the fifth and sixth effects 327 and 328 at an appropriate pressure and for a duration sufficient to reach the desired concentration, which, in one example, is between around 85 and 110 grams of NaOH per liter, and, more preferably, in the range between 95 and 105 grams of NaOH per liter. In one embodiment, the alkaline extraction solution 316 remains in the fifth effect 327 under a negative pressure of approximately -0.84 bar (-84 kPa) and, in the sixth effect 328 under a negative pressure of approximately -0.50 bar (- 50 kPa), to guarantee a concentrated solution 330 having an effective alkali concentration between, for example, approximately 95 and 105 grams of NaOH per liter.
    [048] Advantageously, a processing plant can be configured to employ the inventive process without a significant additional monetary expense for the equipment required. When a plant has been using, for example, six effects for the concentration of weak black liquor left from the cooking stage, two of the effects can be re-employed for use in the concentration of alkaline filtrate produced in the CCE washing process. The reduced number of effects available for black liquor concentration is not significant, because although the capacity for evaporation of black liquor is reduced by approximately 20 to 30%, the quality of the black liquor (final solids concentration) can be maintained, allowing that the black liquor resulting from the four effects is burned in the recovery boiler without any significant impact. However, the use of two of the effects for concentration of alkaline filtrate and recycle, according to the inventive techniques described here, can have a significant impact on the efficiency of the plant. Because the same number of effects can be used for two different processes, a plant can be configured so that the operator can choose between using a conventional process for evaporating weak black liquor in all effects, or allocate some of the effects to the concentration of alkaline filtrate without appreciable negative consequences, still providing improvements in terms of efficiency.
    [049] Returning to figure 2, the concentrated alkaline filtrate solution 217 can be reused, in whole or in part, as a neutralization solution 210 and / or as part of the cooking liquor 211. In one embodiment, the neutralization solution 210 consists entirely of the concentrated alkaline filtrate solution 217. In another embodiment, the neutralization solution 210 comprises the concentrated alkaline filtrate solution 217 and a white liquor, which can be added to the digester first and also optionally used for enrichment of concentrated alkaline filtrate solution 217. In a third embodiment, concentrated alkaline filtrate solution 217 is used as cooking liquor 211. In a fourth embodiment, concentrated alkaline filtrate solution 217 is combined with a white liquor for use like cooking liquor 211.
    [050] The concentrated alkaline filtrate solution 217 that is not reused in cooking stage 221 can be used for other purposes. For example, it can optionally be diverted for other purposes, such as for use in an adjacent production line (such as white liquor), as illustrated by arrow 251 in the example in figure 2. At the same time, the concentrated alkaline filtrate solution 217 may also allow the use of higher concentrations of liquor in the cooking stage 221, thus preventing further deposition of hemicelluloses in the fibers.
    [051] Figures 4 and 5 illustrate and compare a conventional system for an evaporation process in relation to a cold caustic extraction, with a possible modality as explained here. Figure 4 is a diagram of a conventional system 400 reflecting an evaporation process, as it can be used, among other things, with a cold caustic extraction. As shown in figure 4, system 400 includes several effects 461A-D and 462-466. A weak black liquor 413 from a cooking process is received in one of the effects, in this case, in the fourth effect 464, where the evaporation process begins. Pipes 441 and 442, respectively, connect the fourth effect 464 to the fifth effect 465 and the fifth effect 465 to the sixth effect 466. After processing in the sixth effect 466, the semiconcentrated black liquor is moved to the intermediate heat exchangers 450 and 452 From the heat exchanger 452, the semi-concentrated black liquor is provided for the third effect 463, whose product is moved to another intermediate heat exchanger 454.
    [052] From the heat exchanger 454, the semi-concentrated black liquor is then provided for the second effect 462 (a body divided into two liquor circulation units “A” and “B”). After evaporation in the second effect 462, a part of the black liquor is pumped directly to the first effect (concentrator) and the other part is subjected to rapid evaporation in the evaporator 459, under atmospheric pressure, and pumped 432 for ash mixing. The first effect can physically consist of four 461A-D evaporators. The evaporators can be drop film evaporators of the tube and shell type. All four 461 A-D evaporators can be in operation simultaneously, which can allow the production of black liquor with higher concentrations. The ash-containing liquor is pumped from the ash mixing tank to the 461 D evaporator. After evaporation in the 461 D evaporator, the concentrated heavy black liquor is quickly transformed into the fast evaporator 459 and stored in a pressurized heavy liquor tank ( not shown in figure 4).
    [053] Among the outputs of the evaporation system 400 are a heavy (strong) black liquor 430, as well as a condensate 431 which is sent for washing liquor storage. The strong black liquor 430 can be used for the purposes as previously described here. In the 440A condensate tank, the steam condensate of the second, third and fourth effects 462, 463 and 464 is combined to form a clean condensate (“condensate A”) and can be transformed in several stages, until it is subjected to a similar pressure that of a vapor inlet pressure of the sixth effect 466. Condensate A is collected in the clean condensate tank (tank A of condensate tank 440) and can be used elsewhere, for example, on a fiber line.
    [054] The condensate on the clean side of the fourth and fifth effects 464 and 465 forms an intermediate condensate (“condensate B”), which is rapidly transformed or reduced in pressure in stages, until it has a pressure similar to that of the inlet pressure of the sixth effect 466. The transformed condensate B is combined with treated or untreated condensates from other parts of the evaporation system, such as from the clean side of the sixth effect 466, the primary section of the segregated surface condenser 470 and / or the condensate reduction column treated. This combined condensate can generally contain more impurities than condensate A. Condensate B is collected in the intermediate condensate tank (tank B of condensate tank 440), and can be used in other parts of pulp production, such as the caustification plant.
    [055] An encrusted condensate (“condensate C”), which generally contains more impurities than condensate A or condensate B, can be collected from the encrustation side of the fifth and sixth effects 465 and 466, section secondary of the segregated surface condenser and the vacuum system. Condensate C is stored in the fouling condensate tank (tank C of condensate tank 440).
    [056] Figure 5 is a diagram of a system 500 reflecting a process for evaporating filtrate from a cold caustic extraction according to the general principles illustrated in figures 2 and 3. In this example, system 500 uses the same basic configuration of equipment and the same number of effects as the 400 system in figure 4, although this need not be the case in other modalities. The dotted lines in figure 5 show additional connections (including tubes and valves) that can be added to the equipment in figure 4, in order to arrive at the additional CCE filtrate concentration functionality. In figure 5, system 500 again has multiple effects 561A-D and 562-566. The effects 561A-561D, 562 and 563 serve the same general purpose as the corresponding effects 461A-D, 462 and 463 in figure 4. However, in the system 500 shown in figure 5, after the weak black liquor 513 is initially concentrated in the room effect 564, is provided through a bypass tube 537 (as controlled by an added valve 536) for heat exchanger 550 (which is otherwise similar to heat exchanger 450 in figure 4). In this way, the weak black liquor concentration process deviates from the fifth and sixth effects 565, 566.
    [057] Unlike system 400 in figure 4, in system 500 in figure 5, a cold caustic extraction filtrate (CCE) 516 from the CCE washing step is provided through the connector tube 541 for the fifth effect 565, whereby the first part of the concentration process undergoes. A new valve 538 has been added in relation to figure 4, to allow isolation of the fourth effect 564 of the CCE filtrate 516. An optional branch connector tube 539 can be added to connect the CCE filtrate 516 to the sixth effect 566, to allow the option of providing the CCE filtrate directly for the sixth effect 566, if, for example, a smaller amount of concentration is desired. Otherwise, after evaporation in the fifth effect 565, the CCE filtrate semiconcentrate is provided for the sixth effect 566 through a connector tube 542, whereby it undergoes an additional concentration via evaporation to the desired extent.
    [058] The concentrated CCE filtrate 560 can be directed through line 591 to tank C in condensate tank 540, or through line 592 to tank B in condensate tank 540. Regarding the Kraft processing steps described previously, the filtrate of concentrated CCE 560 can be mixed with white liquor, black liquor or other solutions as part of the cooking stage. If desired, the semi-concentrated CCE filtrate can be sent to the heat exchanger 550 from the fifth effect 565 via another additional connector tube 535, as controlled by valve 534. The connector tube 535 also provides the option of using five effects for weak white liquor concentration and only a single effect (the sixth effect) for CCE filtrate concentration. This configuration provides, among other things, significant flexibility in terms of various mixtures and concentrations of cooking and washing solutions. In this embodiment, in which the CCE filtrate is concentrated in the fifth and sixth effects 565 and 566, the condensate flows can be changed via valve switches: for example, the scale side of the fourth effect 564 may be part of the condensate of fouling (condensate C); the condensate on the scale side of the sixth effect 466 may be part of an intermediate condensate (condensate B); and the condensate from the primary section of the segregated surface condenser may be part of the clean condensate (condensate A). EXAMPLES
    [059] The modalities processes of the present invention are demonstrated in the following examples. The analytical results described in the examples are obtained using the following methods.
    [060] The method used for the measurement of pulp solubility S10 and S18 at 25 ° C is based on TAPPI cm-00 Standard T 235, thus incorporated as a reference as fully established here. The pulp is extracted with a sodium hydroxide solution (NaOH) of 10% and 18%, respectively. Dissolved carbohydrates are determined by oxidation with potassium dichromate. Low molecular weight carbohydrates, such as hemicelluloses and degraded cellulose, can be extracted from pulps with sodium hydroxide solutions. The solubility of a pulp in alkali thus provides information on cellulose degradation and on a loss or retention of hemicelluloses during a pulping and bleaching process. In a typical S10 solubility measurement procedure, a 10 gram oven-dried pulp sample is placed in a beaker and 75 ml of 10% by weight NaOH solution is added to the pulp. The mixture is stirred with a dispersing apparatus for a sufficient time until the pulp is completely dispersed. An example of a dispersion apparatus may contain a variable speed motor and a stainless steel agitator with a housing. The speed of the motor and the angle of the blades are adjusted so that no air is drawn into the slurry suspension during agitation. After the pulp is completely dispersed, another 25 ml of 10% NaOH is added to the mixture, to ensure that all pulp fibers are covered by the alkali solution. The beaker containing the mixture is kept in a water bath at 25 + 0.2 ° C for 60 min from the time of the first addition of the NaOH reagent. After this time, around 50 ml of the filtrate is collected in a clean and dry filtration bottle. An aliquot of 10.0 ml_ of the filtrate is mixed with 10.0 ml_ of a 0.5 N potassium dichromate solution in a 250 ml_ flask. For this purpose, 30 mL of concentrated sulfuric acid is added with stirring, during which time the solution becomes hot from chemical reactions. The solution is stirred for 15 minutes, while kept warm. 50 ml of water is then added to the mixture, and the mixture is cooled to room temperature. Two to four drops of ferroin indicator are added to the mixture, and the mixture is titrated with a 0.1 N ferrous ammonium sulfate solution. The titration is repeated using 10 mL of 10% NaOH solution. The solubility S10 is calculated using the following formula: S,% = [(V2-VI) * N * 6.85 * 10] / (A * W) where Vi is the volume of ferrous ammonium sulfate solution used for the filtrate titration, and the unit is milliliter; V2, also in milliliters, is the volume of ammonium sulfate solution used for the titration of a pure 10% NaOH solution, N is the normality of the ferrous ammonium sulfate solution; A, with a unit in milliliters, is the volume of the pulp filtrate used for oxidation; and W is the dry weight in a pulp sample oven, in grams.
    [061] The procedure is the same for determining the S18 solubility, except that an 18% NaOH solution replaces the 10% NaOH solution used above.
    [062] The pulp viscosity in a cupriethylenediamine (CED) solution is determined using a method based on SCAN CM 15-99, thus incorporated as a reference as if fully established here. The method determines the number of intrinsic pulp viscosity in a diluted CED solution. In a typical procedure, a pulp sample is dissolved in the CED solution. The amount of pulp is chosen with respect to the expected intrinsic viscosity number. The heavy pulp sample is placed in a polyethylene bottle (approximately 52 mL in volume), in which residual air is expelled by compressing the bottle. 5 to 10 pieces of copper wire and 25 ml of deionized water are added to the pulp, and the mixture is shaken with a suitable stirring device, until the pulp is completely disintegrated. The typical time interval for disintegration is between 10 and 30 minutes. Another 25 mL of CED solution is added to the mixture. After the residual air is expelled, the bottle is closed tightly and stirred again for approximately 30 minutes, or until the pulp sample is completely dissolved. The temperature of the test solution and the viscometer is adjusted to 25 ° C. A portion of the test solution is aspirated into the suction test viscometer. The efflux time, that is, the time it takes for the meniscus to fall from the upper to the lower mark on the viscometer, is measured. The relative viscosity is calculated using the equation:
    where F is the viscometer calibration factor; Tced, in seconds, is the efflux time for a 50% CED solution; T is the flow time for the test solution, also in seconds. The equivalent value (η * c) can be found in the table attached to the SCAN standard, where η is the intrinsic pulp viscosity with a unit of mL / g, and c is the concentration of the test solution calculated as the divided pulp dry weight. by the volume of the test solution, which is 50 ML in this example.
    [063] The Kappa number (KN) is measured using a method similar to that of the TAPPI T 236 om-99 standard. KN corresponds to the volume (in mL) of a 0.1 N potassium permanganate solution used for the oxidation of one gram of oven dried pulp. In a typical procedure, a pulp sample is disintegrated or dissolved in approximately 300 ml of distilled water. The disintegrated or dissolved pulp sample is transferred to a beaker and sufficient water is added to the pulp mixture, bringing the total volume of the mixture to around 795 mL. 100 ml of a 0.1 N potassium permanganate solution and 100 ml of 4 N sulfuric acid are mixed in a separate beaker, and the mixture is adjusted to 25 ° C quickly. The acidified potassium permanganate solution is added immediately to the test pulp. After the addition, the total volume of the mixture is approximately 1000 + 5 ml. The mixture is allowed to react for ten minutes, after which time, 20 mL of a 1 N potassium iodide solution are added to abruptly cool the reaction. The free iodine content of the mixture is determined immediately after titrating the pulp mixture with a 0.2 N sodium thiosulfate solution. The end point of the titration is indicated by a starch indicator added towards the end of the reaction. Titration is performed without removing pulp fibers. Another titration is carried out with an initial solution without pulp. KN is calculated using the following formula: KN = (p * f) / w where p is the amount of 0.1 N potassium permanganate in milliliters consumed by the test sample; f is a correction factor for a volume of permanganate of 50% and dependent on “p”, which can be found in the Tappi standard; w is the oven dried weight of the pulp sample, and “p” is determined as follows: p = [(ba) * N] / 0.1 where b is the amount of thiosulfate in milliliters consumed in the titration of the initial solution ; a is the amount of thiosulfate consumed in the titration of the pulp sample; and N is the normality of the thiosulfate. EXAMPLE 1 CCE Filtrate Concentration
    [064] According to a first example, a stream of caustic solution very diluted to an effective alkali concentration of 5.6 grams of NaOH per liter is introduced in the fifth effect 327, as shown in figure 3, to start the operation of the plant and to observe its behavior with different levels of alkali concentration. The water is removed from the solution at a reduced pressure of -0.73 bar (73 kPa) at a temperature between 51.5 ° C and 56.8 ° C. After 4 hours and 30 minutes, a caustic solution with an effective alkali concentration of around 50 grams of NaOH per liter, similar to the crude CCE filtrate, is fed in the fifth effect, leaving the sixth effect from a concentration of inlet filtrate of around 50 grams of NaOH per liter. Table I lists the flow, the temperature, the effective alkali concentration and the vacuum level as a function of time. Table I
    EXAMPLE 2 Conventional Kraft Process
    [065] According to a second example, an experimental Kraft process is carried out in a bench scale digester (approximately 20 liters in volume) for simulation of industrial processing. A 20 liter bench scale digester is preheated with steam to 120 ° C for a period of 30 minutes. A suitable amount (such as 4.7 kg kiln-dried) of eucalyptus wood chips is added to the digester. The digester is heated to 165 ° C for a period of 60 minutes, and maintained at 165 ° C for another 40 minutes, to complete the prehydrolysis stage. For a conventional Kraft process (not using CCE filtrates), 4.51 liters of a first white liquor (“WL1”) with an effective alkali concentration of 124.7 g NaOH per liter are added to the digester for fifteen minutes at a temperature of 152 ° C. The typical alkali charge for neutralization is around 12% effective alkali (EA) as NaOH in the weight of dry chips. The digester is then filled with 10.8 liters of hot black liquor with an effective alkali concentration of 25.3 g of NaOH per liter (“HBL1”) added for 15 minutes at a temperature of 140 ° C to complete the step neutralization. Ten liters of a second hot black liquor (“HBL2”) of the same concentration are added to the digester to move the neutralized liquor for a period of 23 minutes at a temperature of 146 ° C, followed by the cooking of liquor consisting of a mixture of 1.0 liter of hot black liquor (“HBL2”) and 4.16 liters of a second white liquor (“WL2”) with an effective alkali concentration of 124.7 g NaOH per liter for a period of 12 minutes at 10 bar (1000 kPa) and 152 ° C. The typical alkali charge for the cooking phase is around 11% effective alkali (EA) as NaOH in the weight of dry chips. The cooking liquor is circulated at a rate of 3 liters per minute for 3 minutes under a pressure of 9.1 bar (910 kPa). The digester is then heated to 160 ° C for a period of 14 minutes, and maintained at 160 ° C for another 23 minutes. The digester is then cooled, and the reaction mixture is washed twice with a dilute caustic solution. Each wash uses 15 liters of an aqueous solution containing approximately 0.2 g of NaOH per liter of solution. The resulting brown raw material shows a Kappa Number of 10.3, a viscosity of 988 ml / g, an S10 solubility of 3.6% and an S18 solubility of 2.7%. The reaction has a yield of 39.3%. When sieved, the mixture has 0.13% of tailings, resulting in a sieving yield of 39.1%. EXAMPLE 3 Use of Weak Concentrated CCE Filtrate as a Neutralization Solution and a Cooking Solution
    [066] According to a third example, the same pulping process as described in Example 2 is repeated, except that the white liquor for the neutralization and cooking stages is replaced by a filtrate from the CCE stage. having an EA of 54 g of NaOH per liter (“CCE54”). The neutralized has a pH of 11.0, and the cooking mixture has an EoC of 18.5 g of NaOH per liter. The P factor for prehydrolysis is 297 and the H factor for the cooking reaction is 419. For this example, the total equivalent effective alkali charge in the wood is respectively: 12% EA as NaOH for the neutralization phase and 11% EA as NaOH for the cooking phase.
    [067] The resulting brown raw material shows a Kappa Number of 10.8, a viscosity of 1118 ml / g, an S10 solubility of 4.5% and an S18 solubility of 3.6%. The reaction has a yield of 40.4%. When sieved, the mixture has 0.09% tailings, resulting in a sieving yield of 40.3%. EXAMPLE 4 Use of Highly Concentrated CCE Filtrate as a Neutralization Solution and a Cooking Solution
    [068] According to a fourth example, the same pulping process as described in Example 2 is repeated, except that two thirds of WL1 and WL2 are replaced by the concentrated CCE filtrate at an effective alkali concentration of 110 g of NaOH per liter. The resulting brown raw material shows a Kappa Number of 9.5, a viscosity of 990 ml / g, an S10 solubility of 4.1% and an S18 solubility of 3.0%. The reaction has a yield of 39.5%. When sieved, the mixture has 0.10% tailings, resulting in a sieving yield of 39.43%.
    [069] Compared to the conventional Kraft process, the process in which two thirds of the white liquor is replaced by the concentrated CCE filtrate produces pulps of similar viscosities (around 990 mg / l in this example) and Kappa numbers like those in the process Conventional kraft. A similar technique is expected to work over a broader range; for example, when between 60% and 75% of the white liquor is replaced by the concentrated CCE filtrate. The slightly lower Kappa number obtained with the concentrated CCE filtrate suggests that the replacement of white liquors with a concentrated CCE filtrate has no negative impact on delignification. The viscosity ratio for Kappa Number - a measure of selectivity in the cooking step - is higher for the process with the concentrated CCE filtrate (104 versus 96 in the traditional process), indicating better cooking selectivity using a concentrated CCE filtrate.
    [070] The S18 solubility increases from 2.7% to 3.0% and the S10 solubility increases from 3.6% to around 4.1%, when the concentrated CCE filtrate replaces part of the white liquors, indicating that some redeposition of hemicelluloses occurs. The level of solubility S18 can be further controlled by other means, if desired.
    [071] It should be possible to optimize the process further by lowering the cooking temperature slightly to obtain the same Kappa Number (around 10.8) and a higher viscosity. Based on the various experiments, it is expected that minor variations in the process, including alkaline levels, relative amounts of white liquor and concentrated CCE filtrate, cooking temperatures and cooking times can be made, as would be determined from routine calculations. or optimizations based on the principles and techniques described here, while still maintaining the resulting brown raw material qualities in a potentially desirable range. For example, the resulting brown raw material is expected to produce a Kappa Number below 10.0, a viscosity below 1000 ml / g, an S18 solubility of no more than 3.0% and / or a ratio of viscosity for Kappa Number of more than 100.
    [072] According to certain modalities exposed here, it is possible to cook with the same or similar viscosity and the same Kappa Number or similar levels using a concentrated CCE filtrate as a traditional Kraft process that uses only fresh white liquor, thus leading to increased efficiency.
    [073] Although preferred embodiments of the invention have been described here, many variations are possible, which remain in the concept and scope of the invention. These variations would become clear to someone of ordinary skill in the art after inspection of the specification and drawings. Therefore, the invention is not to be restricted, except in the spirit and scope of any attached claims.
    权利要求:
    Claims (15)
    [0001]
    1. Method for pulp production using cold caustic extraction for the production of soluble pulp, characterized by the fact that it comprises: the delignification (221) of organic materials (218) in one or more digesters and the treatment (222) of a material resulting brown raw material (212) for the production of a semipurified pulp for use in the production of soluble pulp; the extraction of semipurified pulp with a caustic solution during a cold caustic extraction process (223) for the production of a purified pulp and a solution containing hemicellulose; separating the hemicellulose-containing solution from the purified pulp; washing (224) the purified pulp and collecting a spent washing liquid resulting therefrom; combining the spent washing liquid with the solution containing hemicellulose to form an alkaline filtrate (216); the concentration (225) of the alkaline filtrate (216) to form a concentrated alkaline filtrate (217); and the use of at least a portion of the concentrated alkaline filtrate (217) in at least one of said digesters in relation to the production of soluble pulp.
    [0002]
    2. Method according to claim 1, characterized in that the concentration of the alkaline filtrate is carried out by an evaporation process (225).
    [0003]
    Method according to claim 2, characterized in that the evaporation process (225) is carried out in a plurality of effects connected serially.
    [0004]
    4. Method according to claim 2, characterized in that said evaporation process (225) is carried out at a temperature between 50 ° C and 60 ° C.
    [0005]
    5. Method according to claim 2, characterized in that the evaporation process (225) is carried out at a pressure of -0.6 bar (-60 kPa) and -0.84 bar (-84 kPa).
    [0006]
    6. Method according to claim 2, characterized in that the evaporation process (225) is carried out until said concentrated alkaline filtrate (217) has an effective alkali concentration between 95 and 125 grams of NaOH per liter.
    [0007]
    7. Method according to claim 2, characterized in that the evaporation process (225) is conducted until said concentrated alkaline filtrate (217) has an effective alkali concentration between 100 and 110 grams of NaOH per liter.
    [0008]
    8. Method, according to claim 1, characterized in that the alkaline filtrate (216) is obtained by: separating the solution containing hemicellulose from the purified pulp; and washing the purified pulp and collecting the resulting crude alkaline filtrate.
    [0009]
    9. Method, according to claim 1, characterized by the fact that it also includes the addition of white liquor to the concentrated alkaline filtrate (217) used in said one or more digesters.
    [0010]
    10. Method according to claim 8, characterized in that the ratio of white liquor to concentrated alkaline filtrate (217) is between 1: 1.5 and 1: 2.5.
    [0011]
    11. Method according to claim 1, characterized in that said caustic solution comprises NaOH and Na2S.
    [0012]
    12. Method according to claim 11, characterized by the fact that it still comprises the use of a second portion of the concentrated alkaline filtrate (217) in a different pulp processing production line.
    [0013]
    13. Method, according to claim 1, characterized by the fact that it still comprises the steps of: production of a second brown raw material from the cooking of a second batch of organic materials in one or more of the digesters; washing and sifting the second brown raw material to produce a semi-purified pulp; and the use of cold caustic extraction, extraction of semipurified pulp derived from the second brown raw material to produce a second purified pulp and a second solution containing hemicellulose.
    [0014]
    14. Method according to claim 13, characterized by the fact that: the second brown raw material has an S18 solubility of not more than 3.0% before cold caustic extraction; or the second brown raw material having a Kappa Number of less than 10.0, before cold caustic extraction; or the second brown raw material has a viscosity of 900 to 1100 milliliters per gram, before cold caustic extraction; or the second brown raw material shows a viscosity ratio for Kappa Number of 100 or higher, before cold caustic extraction.
    [0015]
    15. Method according to claim 1, characterized in that the delignification of organic materials comprises the cooking (221) of organic materials in a plurality of batch digesters, using at least a portion of a concentrated caustic solution derived from the stage of caustic cold extraction downstream and, where, the method further comprises returning at least a portion of the concentrated alkaline filtrate (217) to the batch digesters as at least one cooking fluid.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112012028241B1|2020-11-10|pulp processing method and system using cold caustic extraction with reuse of alkaline filtrate
    US8535480B2|2013-09-17|Method and system for pulp processing using cold caustic extraction with alkaline filtrate reuse
    BR112014029701B1|2022-01-11|PROCESS FOR MANUFACTURING DISSOLUTION PULP, LIQUOR, AND, PULP
    US4298426A|1981-11-03|Method and apparatus for treating pulp with oxygen in a multi-stage bleaching sequence
    AU760949B2|2003-05-22|Method and apparatus for pulp yield enhancement
    SE531540C2|2009-05-12|Alkaline pulp preparation process and system for hardwood
    BRPI0810975B1|2018-12-26|Method for Removing Hemicellulose from Cellulosic Fibers Using Ammonia and Hydrogen Peroxide Solution
    Liu et al.2009|Effect of hot-water extraction of woodchips on the kraft pulping of eucalyptus woodchips
    BR112021000329A2|2021-04-06|PROCESS FOR SEPARATING THE CELLULOSIS PART OF A RAW MATERIAL COMPOSITION UNDERSTANDING POLYESTER AND A COMPOSITION CONTAINING CELLULOSIS, CELLULOSIS COMPOSITION, MIXTURE UNDERSTANDING POLYESTER HYDROLYSIS PRODUCTS, PULP, DISPENSER POLYESIS, POLYESIS, POLYESIS, POLYESIS AND POLYESIS. PAPER
    AU2010202496B2|2015-04-16|Method and system for high alpha dissolving pulp production
    JP5694513B2|2015-04-01|Method and system for processing pulp using cold caustic soda extraction by reuse of alkaline filtrate
    CN100381636C|2008-04-16|Bleaching method of cotton stalk chemical pulp
    Annergren et al.2014|Sulfate cooking-a commercially dominating and continously improving pulping process
    US1602553A|1926-10-12|Process of producing pulp high in resistant crllulose
    Potgieter2018|Improving dissolving wood pulp quality using Brown-stock fractionation
    BR112020013627A2|2020-12-01|process to produce microcrystalline cellulose
    BR112020025159A2|2021-03-09|GROSS PULP, CELLULOSE Ether PRODUCTS MADE FROM THE SAME, AND RELATED METHODS FOR MANUFACTURE PULP AND CELLULOSE ETHER PRODUCTS
    CA2707330C|2017-11-21|Method and system for high alpha dissolving pulp production
    US3201303A|1965-08-17|Vacuum-venturi process of rapidly digesting pulp
    BR102015014413A2|2019-04-24|CELLULOSE CONTENT INCREASE IN EUCALYPTUS WOOD MANUFACTURE
    MXPA00001134A|2001-11-21|Method and apparatus for pulp yield enhancement
    SE501309C2|1995-01-09|Pulp production by digestion of a mixture of cellulose-based recycled material and raw wood
    同族专利:
    公开号 | 公开日
    EP2567023B1|2014-10-15|
    PT2567022E|2014-12-23|
    CN102985610B|2015-08-12|
    WO2011138633A1|2011-11-10|
    AU2010352692A1|2013-01-10|
    CA2744250C|2016-10-11|
    RU2012151858A|2014-06-10|
    CN103003487A|2013-03-27|
    EP2567023A1|2013-03-13|
    ES2525263T3|2014-12-19|
    KR20130038861A|2013-04-18|
    MY157311A|2016-05-31|
    NZ604002A|2014-02-28|
    KR101512550B1|2015-04-17|
    BRPI1015676A2|2013-07-30|
    JP5808795B2|2015-11-10|
    AU2010352692B2|2014-07-03|
    RU2523973C1|2014-07-27|
    KR20130120982A|2013-11-05|
    EP2567022B1|2014-10-15|
    MY155796A|2015-11-30|
    CA2744250A1|2011-11-04|
    CN103003487B|2016-04-27|
    JP2013531139A|2013-08-01|
    CN102985610A|2013-03-20|
    PT2567023E|2014-12-23|
    BRPI1015676B1|2019-03-19|
    EP2567022A1|2013-03-13|
    ES2525490T3|2014-12-23|
    WO2011138634A1|2011-11-10|
    KR101613338B1|2016-04-18|
    CL2012003082A1|2013-04-01|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3988198A|1973-05-31|1976-10-26|International Telephone And Telegraph Corporation|Method for treating hemi caustic effluents|
    CH686682A5|1992-05-05|1996-05-31|Granit Sa|Production of pulp according to the SAP procedure.|
    AT398588B|1992-12-02|1994-12-27|Voest Alpine Ind Anlagen|METHOD FOR THE PRODUCTION OF VISCOSE CELLS|
    US5489363A|1993-05-04|1996-02-06|Kamyr, Inc.|Pulping with low dissolved solids for improved pulp strength|
    BR9506622A|1994-01-21|1997-09-16|Rayonier Inc|Process to improve the characteristics of a pulp useful for the production of a soft pulp or a pulp for high absorption applications process to improve the absorption of pulps and increase the yield of absorbent fibers by fluffing the same processes to improve the properties of useful pulps process pulps to improve the fast absorbing characteristics of a pulp useful for process applications for the production of an absorbent device having an external capture layer and an internal pulp absorbent element for an absorbent device consisting of at least one element of cotato layer absorption material and process to improve the absorption of a cellulosic material into a fibrous form of the cellulosic material|
    FI103898B1|1994-01-24|1999-10-15|Sunds Defibrator Pori Oy|A process for producing prehydrolyzed pulp and / or pulp|
    SE9401769L|1994-05-24|1995-11-25|Nils Mannbro|Tile impregnation in pulp cooking with sulphidic alkali|
    US6248208B1|1995-06-02|2001-06-19|Andritz-Ahlstrom Inc.|Pretreatment of chips before cooking|
    FI105929B|1996-05-30|2000-10-31|Sunds Defibrator Pori Oy|Improved process for batch production of sulfate cellulose|
    FI122654B|1997-12-08|2012-05-15|Ovivo Luxembourg Sarl|Process for making paper cellulose pulp|
    FI115640B|2000-11-03|2005-06-15|Metso Paper Inc|Hot black liquor using cooking process|
    FI20002586A|2000-11-24|2002-05-25|Metso Paper Inc|Process for alkaline batching when cooking fiber material|
    SE0104247L|2001-12-14|2002-10-22|Kvaerner Pulping Tech|Pre-treatment of chips with fresh white liquor before treatment with black liquor|
    US6896810B2|2002-08-02|2005-05-24|Rayonier Products And Financial Services Company|Process for producing alkaline treated cellulosic fibers|
    FI120361B|2003-12-31|2009-09-30|Gl & V Finance Hungary Kft|Batch cooking process for the production of kraft pulp|
    US7812153B2|2004-03-11|2010-10-12|Rayonier Products And Financial Services Company|Process for manufacturing high purity xylose|
    FI120547B|2004-10-04|2009-11-30|Metso Paper Inc|Alkaline cooking process and pulp making plant|
    FI122841B|2004-10-04|2012-07-31|Metso Paper Inc|Method and apparatus for making cellulosic pulp|
    AT503610B1|2006-05-10|2012-03-15|Chemiefaser Lenzing Ag|METHOD FOR PRODUCING A PULP|
    FI20085425A|2008-05-08|2009-11-09|Metso Paper Inc|Sulfaattiesihydrolyysikeittomenetelmä|BR102014027199A2|2014-07-14|2016-04-26|Nalco Co|method and chemical compositions to improve chemical pulp manufacturing efficiency|
    AU2010202496B2|2010-05-04|2015-04-16|Bahia Specialty Cellulose Sa|Method and system for high alpha dissolving pulp production|
    CN107379803A|2012-03-28|2017-11-24|精工爱普生株式会社|Ink jet recording method, ultraviolet curable ink, ink-jet recording apparatus|
    AR091998A1|2012-05-03|2015-03-18|Annikki Gmbh|CELLULOSE PREPARATION PROCEDURE WITH LIGNIN LOW CONCENTRATION|
    CN104379833B|2012-05-28|2016-05-11|索德拉细胞公司|New technology and the dissolving pulp of manufacturing by this technique|
    CN105518212B|2013-09-11|2018-09-04|日本制纸株式会社|Dissolve the manufacturing method of kraft pulp|
    CN103469696B|2013-09-26|2016-02-03|句容市植保植检站|A kind of brown paper and manufacture method thereof|
    WO2016058098A1|2014-10-15|2016-04-21|Canfor Pulp Ltd|Integrated kraft pulp mill and thermochemical conversion system|
    SE538454C2|2014-11-27|2016-07-12|Valmet Oy|Method for displacement in batch digesters|
    CN105442370B|2015-11-27|2017-12-22|福建农林大学|A kind of method that bleached bamboo pulp plate prepares dissolving pulp|
    CN109843932A|2016-03-31|2019-06-04|凯米罗总公司|The method for preparing hemicellulose composition|
    CN106368032B|2016-09-19|2018-06-22|华南理工大学|Method that is a kind of while preparing cellulose fiber peacekeeping hemicellulose solution|
    SE540778C2|2016-12-23|2018-11-06|Soedra Skogsaegarna Ekonomisk Foerening|A method of manufacturing dissolving pulp using coniferous wood material|
    CN109930414A|2017-12-15|2019-06-25|中国制浆造纸研究院有限公司|A kind of waste paper deinking agent based on cold alkali density waste liquid|
    CN109930417A|2017-12-15|2019-06-25|中国制浆造纸研究院有限公司|A kind of recoverying and utilizing method of cold alkali density waste liquid|
    CN109930415A|2017-12-15|2019-06-25|中国制浆造纸研究院有限公司|A method of improving oxygen bleaching pulp strength|
    AU2019206607A1|2018-01-12|2020-07-16|Circ, LLC|Methods for recycling cotton and polyester fibers from waste textiles|
    SE1850733A1|2018-06-15|2019-12-16|Valmet Oy|Method and assembly for optimizing filtrate circulation in a kraft process|
    KR101952316B1|2018-08-09|2019-02-27|무림피앤피 주식회사|Method of manufacturing a dissolving pulp|
    WO2022008790A1|2020-07-06|2022-01-13|Amppc Finland Oy|A cooking method|
    CN112227103A|2020-09-29|2021-01-15|大连工业大学|Method for reducing dust degree of reed pulp and papermaking paper|
    法律状态:
    2018-04-10| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2019-03-19| B06T| Formal requirements before examination|
    2020-02-04| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application according art. 36 industrial patent law|
    2020-07-07| B09A| Decision: intention to grant|
    2020-11-10| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 10 (DEZ) ANOS CONTADOS A PARTIR DE 10/11/2020, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    RU2010118498|2010-05-04|
    RU2010118498/05A|RU2535804C2|2010-05-04|2010-05-04|Method and system of producing soluble cellulose mass with high content of alpha-cellulose|
    KR10-2010-0042681|2010-05-06|
    KR1020100042681A|KR20110123184A|2010-05-06|2010-05-06|Method and system for high alpha dissolving pulp production|
    US12/789,265|US8535480B2|2010-05-06|2010-05-27|Method and system for pulp processing using cold caustic extraction with alkaline filtrate reuse|
    US12/789,265|2010-05-27|
    PCT/IB2010/002244|WO2011138633A1|2010-05-04|2010-08-18|Method and system for pulp processing using cold caustic extraction with alkaline filtrate reuse|
    [返回顶部]