Abstract: The objective of the present disclosure is to provide a method for easily evaluating the degree of cleanliness of recycled material derived from used sanitary products. The evaluation method according to the present disclosure has the following configuration. This method for evaluating a degree of cleanliness of recycled material derived from used sanitary products includes: a preparation step of preparing a dispersed aqueous solution in which the recycled material is dispersed in water; a separation step of subjecting the dispersed aqueous solution to centrifugal separation to separate the dispersed aqueous solution into a liquid component and a solid component; and a measuring step of measuring the concentration of protein in the liquid component using a protein measuring means.

Abstract: The purpose of the present disclosure is to provide a method for producing pulp fibres for saccharification from the pulp fibres of used sanitary items, said pulp fibres for saccharification having low lignin contents distributed within a narrow range, and enabling the production of pulp fibres for saccharification having superior saccharification properties.

Abstract: A belt for suspending and/or driving an elevator car includes a tension member extending along a length of the belt, the tension member including a plurality of fibers bonded in a first polymer matrix, the plurality of fibers extending parallel to and discontinuous along a length of the belt and arranged with one or more lengthwise extending gaps between lengthwise adjacent fibers. A jacket substantially retains the tension member. A method of forming a tension member for an elevator system belt includes arranging a plurality of fibers into a fiber bundle. The plurality of fibers extend parallel to a length of the belt and have one or more lengthwise extending gaps between lengthwise extending fibers. The plurality of fibers is bonded to a first polymer matrix.

Abstract: There is provided a cellulose based fiber made of a i) cellulose dissolving pulp, and ii) a recycled cellulose textile, which is treated to swell the cellulose with a reducing additive and a) bleached with oxygen at alkaline conditions with a pH in the range 9-13.5 and/or b) bleached with ozone at acid conditions below pH 6, wherein the cellulose based fiber is manufactured with one selected from a Viscose process and a Lyocell process. Advantages include that the tensile strength of the fiber is improved and it is possible to manufacture improved cellulose fibers which comprise a fraction of recycled material.

Abstract: The disclosure relates to a method for depolymerizing lignin. The method includes reacting a lignin compound with a thiol compound to depolymerize the lignin compound and to form a depolymerized lignin product having a reduced molecular weight relative to the lignin compound prior to reacting. The method can further include forming an oxidized thiol reaction product between two thiol groups from one or more thiol compounds, and then reducing the oxidized thiol reaction product to re-form or regenerate the thiol compound for further lignin depolymerization.

Abstract: A composition comprising nanocellulose is disclosed, wherein the nanocellulose contains very low or essentially no sulfur content. The nanocellulose may be in the form of cellulose nanocrystals, cellulose nanofibrils, or both. The nanocellulose is characterized by a crystallinity of at least 80%, an onset of thermal decomposition of 300° F. or higher, and a low light transmittance over the range 400-700 nm. Other variations provide a composition comprising lignin-coated hydrophobic nanocellulose, wherein the nanocellulose contains very low or essentially no sulfur content. Some variations provide a composition comprising nanocellulose, wherein the nanocellulose contains about 0.1 wt % equivalent sulfur content, or less, as SO4 groups chemically or physically bound to the nanocellulose. In some embodiments, the nanocellulose contains essentially no hydrogen atoms (apart from hydrogen structurally contained in nanocellulose itself) bound to the nanocellulose.

Abstract: In some embodiments, a method may include treating pulp. The method may include contacting a wood pulp with a singlet oxygen source. The method may include contacting the wood pulp with an alkaline peroxide source. The singlet oxygen source may include a peracetate oxidant solution and generating a reactive oxygen species. The peracetate oxidant solution may include peracetate anions and a peracid. In some embodiments, the peracetate solution may include a pH from about pH 10 to about pH 12. In some embodiments, the peracetate solution has a molar ratio of peracetate anions to peracid ranging from about 60:1 to about 6000:1. In some embodiments, the peracetate solution has a molar ratio of peracetate to hydrogen peroxide of greater than about 16:1. The peracetate oxidant solution may provide enhanced treatment methods of bleaching, brightening, and delignifying pulp fibers involving the use of peracetate oxidant solutions.

Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: Disclosed herein are methods for the production of fuels, chemicals, or materials from biomass-derived lignin, cellulose, and hemicellulose. Also provided are methods for the production of polyhydroxyalkanoates from lignocellulosic biomass and the subsequent thermal and catalytic conversion of polyhydroxyalkanoates to hydrocarbons. In addition, methods for the production of ethanol from the fermentation of polysaccharides are described.

Abstract: A composition comprising nanocellulose is disclosed, wherein the nanocellulose contains very low or essentially no sulfur content. The nanocellulose may be in the form of cellulose nanocrystals, cellulose nanofibrils, or both. The nanocellulose is characterized by a crystallinity of at least 80%, an onset of thermal decomposition of 300° F. or higher, and a low light transmittance over the range 400-700 nm. Other variations provide a composition comprising lignin-coated hydrophobic nanocellulose, wherein the nanocellulose contains very low or essentially no sulfur content. Some variations provide a composition comprising nanocellulose, wherein the nanocellulose contains about 0.1 wt % equivalent sulfur content, or less, as SO4 groups chemically or physically bound to the nanocellulose. In some embodiments, the nanocellulose contains essentially no hydrogen atoms (apart from hydrogen structurally contained in nanocellulose itself) bound to the nanocellulose.

Abstract: A bleached softwood kraft pulp fiber with high ?-cellulose content and a low CED viscosity is provided, A surfactant treated fiber useful in the production of chemical derivatives is also described. Methods for making the kraft pulp fiber and products made from it are also described.

Abstract: The present disclosure relates to producing paper or paperboard having improved stiffness and strength, compared to the conventional paperboard at the same basis weight. It also discloses a method of wood pulping having a significantly increased yield and providing fiber pulps with enhanced properties such as strength and stiffness. Wood chips are chemically pulped to a high kappa number, providing a rejects component and an accepts component. The rejects component is subjected to a substantially mechanical pulping process, optionally in a presence of bleaching agent, prior to blending back into the accepts component. The resulting fiber blend is washed, optionally bleached, and subjected to a papermaking process to provide paper or paperboard with enhanced strength and stiffness at low basis weight.

Abstract: Disclosed herein are flame retardant materials, and in particular materials and processes for phosphorylating materials for flame retardant applications.

Abstract: A method for producing mechanical paper pulp comprises: impregnating unprocessed wood, whereby unprocessed wood is exposed to an impregnating composition comprising at least a laccase enzyme and a formula mediator (I), wherein R1 and R2 are identical or different groups, chosen from among a hydrogen atom, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising 1 to 14 carbon atoms, wherein each hydrocarbon chain can be replaced by one or more functional groups chosen from among —OH, —SO3, benzyl, amino, mercapto, keto or carboxyl, wherein R1 and R2 in combination can form a cyclical structure, to achieve impregnation of the wood; and mechanically refining the impregnated wood, such that a mechanical paper pulp is obtained. The disclosure also relates to an impregnating composition used in this method and to the use thereof in a method for producing mechanical paper pulp, as well as to a method for producing paper.

Abstract: A method for regeneration of a cellulose containing material, comprises the steps: a) exposing the cellulose containing material to oxygen with an alkali aqueous solution at a pH of at least 9, and a temperature of at least 20° C., b) dispersing the cellulose containing material in the alkali aqueous solution, wherein the temperature of the alkali aqueous solution is lowered below 15° C., and wherein the pH of the alkali aqueous solution is above 9, c) adding an organic solvent to the dispersion to precipitate cellulose, and d) separating the precipitated cellulose by at least one method selected from filtering and centrifugation. The method makes it possible to maintain a high alkali pH value in the process, which saves costs since the pH value does not have to be lowered by additions of various additives. The method makes it possible to remove non-cellulose parts of the cloth.

Abstract: A bleached softwood kraft pulp fiber with high alpha cellulose content and increased brightness and whiteness is provided. Methods for making the kraft fiber and products made from it are also described.

Abstract: Certain exemplary embodiments provide methods for reducing a concentration of a contaminant associated with a medium, which can be any substance or material, such as soil, water, air, and/or fluid. In one exemplary method, the medium is treated with a ferric chelate and an oxidizing agent in amounts effective to oxidize at least a portion of the contaminant.

Abstract: A sensor, and methods of making, for determining the concentration of an analyte, such as glucose, in a biological fluid such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. The sensor includes a working electrode and a counter electrode, and may include an insertion monitoring trace to determine correct positioning of the sensor in a connector. The sensor is calibration-adjusted, eliminating the need for a user to enter a calibration code or for the meter to read a calibration code.

Abstract: The present invention relates to a method for an accelerated fermentation in a fermentation tank 2 with at least a tank cone 2a and a connection flange 4, in particular for beer production. The method comprises the steps: a) sucking in of fermentation fluid M1 from the tank 2 via a first circulation pipe 40 by means of a circulation pump 30; b) inducing of the drive fluid M1 that is now pumped by the circulation pump 30 via a second circulation pipe 50 in a mixing member 10 that is arranged within the tank cone 2a at a height L of 350 mm-1800 mm between the bottom edge of the connection flange 4 and the bottom edge of the mixing member 10; and c) generating of a jet directed upwards and exiting through an outlet opening 18 of the mixing member 10, so that the yeast cells stay for a longer time in suspension in the tank 2 by means of an in such a way improved convective current. The invention relates moreover to a corresponding device.

Abstract: The present disclosure relates to methods for detoxifying a hydrolysate obtained from a lignocellulosic biomass and methods of producing ethanol from the detoxified hydrolysate. The present methods provide detoxified hydrolysates in which the quantity of compounds that are deleterious to fermenting microorganisms are substantially reduced relative to the starting hydrolysate and in which the amount of fermentable sugars loss is minimal.

Abstract: Methods for seating water and gulp used in a paper or cardboard manufacturing process. Oxygen and nutrients are added to the water or pulp to increase the activity of aerobic bacteria resulting in a reduction of organic substances such as fatty acids. Alternatively oxygen alone is added to the water or pulp to reduce all both aerobic and anaerobic bacterial activity.

Abstract: A method to make pulp adapted for forming a corrugated medium, the method includes: cooking chips in a cooking vessel using a caustic carbonated pulping soda/caustic (SC) cooking liquor injected into the cooking vessel; fiberizing the chips discharged from the cooking vessel to form a pulp, and removing lignin from the pulp or oxidizing lignin in the pulp by injecting oxygen (O2) into the fiberized pulp.

Abstract: An omnibus process of pulping and bleaching lignocellulosic materials in which a charge of a lignocellulosic material is biopulped and/or water extracted prior to pulping and bleaching. The lignocellulosic material may be mechanically pulped and bleached in the presence of an enzyme that breaks lignin-carbohydrate complexes. The aqueous extract in embodiments including a water extract step is separated into acetic acid and hemicellulose sugar aqueous solutions.

Abstract: A method of treating and utilizing liquid flows at a chemical pulp mill including stages for: a) chemical pulp is produced in an alkaline cooking process, b) the brown stock generated in the cooking is treated, said treatment comprising washing of the stock and preferably oxygen delignification and subsequent washing of the stock, c) a bleaching process for the brown stock, the bleaching sequence comprising at least one stage using chlorine dioxide and additionally at least one oxidizing bleaching stage and having at least two washing stages for treating the stock with liquids and for producing filtrates, and d) filtrates from stage c) are purified at an effluent treatment plant of the chemical pulp mill, which comprises at least biological treatment, for obtaining purified effluent. The method further includes a stage e), where the purified effluent with a color of 200 mg/l (Pt color) or more and a COD value of over 150 mg/l is used as pulp treatment liquid in stage c).

Abstract: The present disclosure comprises methods, apparatus, components, and techniques for pretreatment of biomaterials using targeted wet oxidation. The targeted wet oxidation pretreatment is an upstream method for converting solid biomass into fuels and/or specialty chemicals. Embodiments of the present disclosure comprise methods carried out on biomaterials to selectively oxidize lignin components of the biomass, thereby resulting in bio accessible/digestible biomass fibers. In embodiments of the present disclosure, such methods may comprise pretreatment processes to prepare the biomaterials for a subsequent fermentation or other like conversion may be carried out to result in useful bio fuels or other bioproducts.

Abstract: A circular utilization method in pulping and papermaking processes with straw Primary pulp is obtained by digesting straw raw material according to the ammonium sulfite method. Concentrated black liquor is extruded from the primary pulp; paper pulp and diluted black liquor. The concentrated black liquor and the diluted black liquor are mixed, and a contaminated condensate is obtained. A residual concentrate or the concentrated black liquor is used for preparing a fertilizer. The contaminated condensate is mixed with one or more of the waste material obtained from stock preparation, a crop byproduct or organic waste, and substrate or fertilizer is obtained by fermenting the nitrogen source of the contaminated condensate or ammonium sulfite, or using the contaminated condensate for desulfurizing flue gas. Ammonia and flue gas are reacted to obtain the ammonium sulfite as a digestion agent; and water from recycling is used in corresponding phases of the pulping process.

Abstract: A raw paper prepared by a mixed pulp including straw pulp, which can be used to prepare textbooks, writing papers and office paper with good performance, and the producing method of said raw paper are provided. The weight proportion of the straw pulp in the mixed stock is from 10% to 100%, and the straw pulp has a hardness of KMnO4 value 10-17, an average fiber length of 0.1-2.5 mm, a tensile index of 23-57 Nm/g, a tearing index of 3.0-6.0 mN·m2/g, a folding endurance index of 2-6 kPa·m2/g and a whiteness of 28-50%. Either, the L value of the hue of said raw paper is 65-95, a value is 0-5, and b value is 0-40. The KMnO4 value of hardness of the pulp after oxygen delignification is 10-14. The method includes: adding grass-series raw material into a digester, then adding cooking liquor, heating the cooking liquor to 100-200°, pressurizing to 0.3-0.9 MPa, cooking for 150-250 min, extruding the pulp, washing and obtaining the straw pulp.

Abstract: Provided is a process for manufacturing shaped cellulose materials from lignocellulose where a dissolving grade pulp is manufactured and dissolved in an aqueous alkaline or acidic solvent system forming a solution suitable for shaping new cellulose structures including fibers, films and cellulose derivatives. At least a part of the spent cellulose dissolving or cellulose shaping chemicals are recovered in one or more unit operations in a pulp mill chemical recovery cycle.

Abstract: A method for the production of alcohol and other bioproducts from power boiler woody biomass extract containing hemicelluloses, with or without combining extract from wood prior to Kraft cooking. The process is integrated with the host Kraft pulp mill plant process to minimize the heat loss from extracting hemicelluloses and the energy used in the process.

Abstract: A method for producing bleached pulp, including processing unbleached pulp obtained by cooking a lignocellulose substance, followed by treatment with peroxomonosulfuric acid and thereafter by multistage chlorine-free bleaching treatment starting from chlorine dioxide treatment; a method for producing bleached pulp, including processing unbleached pulp for alkali-oxygen bleaching followed by chlorine-free bleaching treatment or totally chlorine-free bleaching treatment to bleach it to a degree of brightness of from 70 to 89%, and further followed by treatment with peroxomonosulfuric acid; and paper produced by the use of the bleached pulp produced according to these production methods, at a papermaking pH of at most 6.

Abstract: An omnibus process of pulping and bleaching lignocellulosic materials in which a charge of a lignocellulosic material is biopulped and/or water extracted prior to pulping and bleaching. The lignocellulosic material may be mechanically pulped and bleached in the presence of an enzyme that breaks lignin-carbohydrate complexes. The aqueous extract in embodiments including a water extract step is separated into acetic acid and hemicellulose sugar aqueous solutions.

Abstract: Provided is an unbleached paper product made from grass type pulp, the unbleached paper product has a brightness of 35-60% ISO, the grass type pulp is unbleached. The unbleached paper product includes an unbleached toilet paper, an unbleached hand towel, an unbleached wiping paper, an unbleached duplicating paper, an unbleached meal container, an unbleached food wrapping paper and an unbleached printing paper. The paper products have a high intensity and have no detection of dioxin and absorbable organic halides in the harmful substance detection test.

Abstract: A method of manufacturing high purity fiber cement grades of cellulose fibers is described. Additional washing steps, coupled with an elevated temperature, are used in the process to extensively wash the pulps and remove substantially all COD components remaining in the pulps. The pulps are counter-currently washed by diffusion and dewatering at elevated temperatures following the brown stock washer systems. During the additional washing steps, the pulps are soaked in counter-current heated water for a pre-determined time and some chemicals may be introduced to chemically break down the COD components in the pulps and to make them more soluble in the aqueous solution. The additional washing steps can be performed using existing equipment at conventional pulp mills.

Abstract: A method for treating a prebleached chemical pulp including a step of ozone treatment of the pulp, carried out at a temperature above 60° C., advantageously above 65° C. and even more advantageously above or equal to 70° C.

Abstract: The invention relates to a method for manufacturing papermaking pulp, including: a step of refining wood, including an ozone treatment, so as to obtain a mechanical pulp; a deacidification step including placing the mechanical pulp in contact with a deacidification composition including at least one alkaline agent for more than one hour; and a bleaching step including placing the deacidified pulp in contact with a bleaching composition; wherein the pH varies by less than 0.2 point during the last 30 minutes of the deacidification step, and the pH is 6. to 10 at the end of the deacidification step.

Abstract: A method of manufacturing high purity fiber cement grades of cellulose fibers is described. Additional washing steps, coupled with an elevated temperature, are used in the process to extensively wash the pulps and remove substantially all COD components remaining in the pulps. The pulps are counter-currently washed by diffusion and dewatering at elevated temperatures following the brown stock washer systems. During the additional washing steps, the pulps are soaked in counter-current heated water for a pre-determined time and some chemicals may be introduced to chemically break down the COD components in the pulps and to make them more soluble in the aqueous solution. The additional washing steps can be performed using existing equipment at conventional pulp mills. A formulation and a process of making fiber reinforced cement composite materials are also described using the low COD and high purity cellulose fibers.

Abstract: This invention relates to an improved bleaching process for bleaching pulp comprising at least one bleaching stage which comprises treating a hardwood pulp with a bleaching agent comprising ClO2 in the presence of a weak base such as, for example, Mg(OH)2 preferably at pH from about 3.5 to about 6.5. The invention is also relates a bleaching process for bleaching pulp having two or more bleaching stages, at least one of which and preferably two of which comprises treating a pulp with a bleaching agent comprising ClO2 in the presence of a weak base such as, for example, Mg(OH)2 preferably at pH from about 3.5 to about 6.5.

Abstract: A method for treating mechanical pulp. Resinous mechanical pulp is brought into process in a process water flow. The resinous pulp is ozonated at a temperature between 80 and 87° C. and at pH less than 4. The pH of the pulp is adjusted after the ozonation process to correspond to the pH required in bleaching. The pulp is bleached.

Abstract: Provided is a process for producing bleached pulp, including subjecting unbleached pulp, which is obtained by cooking a lignocellulose substance, to alkali-oxygen bleaching treatment and then subjecting the alkali-oxygen bleached pulp to chlorine-free bleaching treatment including chlorine dioxide treatment, wherein in at least one chlorine dioxide treatment stage in which the chlorine dioxide treatment is performed, monopersulfuric acid is used in combination. The amount of chlorine dioxide to be used is reduced and the colour reversion resistance of the bleached pulp is improved by this process.

Abstract: A process of bleaching a wood pulp includes contacting the pulp with ozone to delignify the pulp in an ozone bleaching stage. A phosphonate chelant is added to the pulp so that the chelant is present with the pulp during the bleaching stage. The process excludes washing of the pulp to remove chelant between the chelant addition and the bleaching stage.

Abstract: A method of manufacturing bleached mechanical and chemithermomechanical pulp is provided, having enhanced bleaching effect, wherein lignocellulose material is passed through at least one preheater or through a chemical treatment system, a steam separator and a refiner where the lignocellulose material is converted into a pulp suspension which, after steam separation, is passed at least to a storage vessel and to a screening department, from which the major part of the pulp suspension is separated as a substantially finished product or is separated and further treated. The reductive bleaching agent is added to the advancing pulp suspension without a bleaching tower. The method is characterized by adding the bleaching agent at a location downstream of the refiner and upstream of the screening department, and by bleaching the pulp under drastic conditions of temperature and minimized oxygen access at the location and immediately downstream of the location.

Abstract: A method for treating a prebleached chemical pulp including a step of ozone treatment of the pulp, carried out at a temperature above 60° C., advantageously above 65° C. and even more advantageously above or equal to 70° C.

Abstract: A method of producing a modified pulp comprising treating wood chips in an extraction process to remove hemicellose to form treated wood chips; and subjecting said treated wood chips to chemical or semichemical pulping to form a modified Kraft pulp wherein the amount of hemicellulose contained in the modified Kraft pulp is from about 5 to about 10% by dry weight of the modified pulp.

Abstract: A process to enhance delignification or bleaching in chemical or mechanical pulps comprising generation of singlet oxygen as a separate step and subsequent transport of singlet oxygen to pulp to effect bleaching or brightening of the pulp.

Abstract: The method is for the improved oxygen delignification of cellulose pulp with a medium consistency of 8-16%. The fraction of dissolved oxygen can be maintained at a high level throughout the process by the use of high pressure, greater than 15.0 bar, and by repeated agitative mixing while maintaining the high pressure. A fraction just over 20% of the total oxygen added is dissolved in the fluid phase such that the amount of oxygen in the fluid phase is maintained at a high level throughout the complete high-pressure section. This means that the amount of oxygen that is dissolved in the fluid phase and that penetrates the cellulose fibers can be maintained at an optimal high level throughout the process for improved delignification of the cellulose.

Abstract: A method for producing paper pulp from a lignocellulosie vegetable raw material. The method includes contacting the raw material with a mixture of formic acid and acetic acid (in an amount more than 5 wt. % of the mixture) at a temperature and for a suitable reaction time, the whole being performed at room temperature. The paper pulp is separated from the organic phase and optionally bleached with ozone. The organic phase is treated to enable the recycling of the formic and acetic acids and the extraction of lignins, sugars and excess acetic acid.

Abstract: The method is for bleaching cellulose pulp in a bleach line that has at least two bleaching steps. The filtrate distribution is led up through the bleaching line counter-currently to the flow of cellulose pulp established in the bleaching line. A single joint main conduit is used for the bleaching steps. Wash filtrates obtained from the wash steps, used after or before the bleaching step, are led in conduits to branch locations on the main conduit that are positioned downstream of the branch location for drawing off of wash and/or dilution liquor for the wash step in question. All branch points in the joint main conduit are in fluid communication with one another along the main conduit.

Abstract: The present invention discloses methods of bleaching chemical pulp that use xylanase enzymes after chemical bleaching. The method comprises the steps of carrying out a chlorine dioxide stage to produce a partially bleached pulp, treating the partially bleached pulp with a xylanase enzyme, optionally in the presence of oxygen and hydrogen peroxide, in a mild extraction stage, then bleaching the pulp with a second chlorine dioxide stage. The method allows the mill to decrease the usage of sodium hydroxide or other alkali, while decreasing the use of chlorine dioxide, and possibly improving the yield and strength of the pulp, while maintaining a similar level of bleached brightness of the pulp. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

Abstract: A method for bleaching cellulosic pulp is disclosed, with one embodiment revealing a three-step bleaching method for cellulosic pulp comprising an activating bleach step, an alkaline peroxide step, and a reductive bleach step. The cellulosic pulp treated according to the present invention may possess a greater GE brightness gain than if treated according to conventional methods, while not suffering a significant loss of lignin. The cellulosic pulp may comprise recycled fibers, including those with high groundwood content. The bleaching method may also decrease the pH of the pulp.

Abstract: A system for treating pulp comprises a dewatering device (2) for dewatering the pulp to a fiber concentration of at least 20%, a closed pulp-shredding vessel (16) for shredding the dewatered pulp, and an outlet pipe (22) from the pulp-shredding vessel. A transport screw (18) is arranged in the outlet pipe for transporting the shredded pulp from the pulp-shredding vessel through the outlet pipe through a reactor vessel (6) for bleaching the shredded pulp through reaction with ozone gas. The outlet pipe (22) is designed with a heightened roof portion (27), so that an upper gas space (29) free from pulp is formed in the outlet pipe between the roof portion and the transport screw. A flow-restraining member in the form of a partition wall (31) is arranged in the upper gas space in the outlet pipe for restraining the gas flow through the gas space, whereby the pumping action of the transport screw in the outlet pipe is decreased.