Abstract: In general, the present disclosure is directed to compositions and processes to increase pulp yield, reduce extractives, and reduce scaling in a chemical pulping process. In one particular embodiment, for instance, the present disclosure is directed to a composition comprising a surface active agent, an alkaline mixture, at least one polymer, the polymer having a linear backbone segment having two ends, at least one phosphorus component, the phosphorus component chemically linked along the linear backbone segment of the polymer, and at least one end component, the end component chemically linked to one or both ends of the linear backbone segment of the polymer.

Abstract: A wood pulping process includes producing weak black liquor and cooling the liquor as well as recovering heat therefrom by directing the weak black liquor through a spray film evaporator. A feed or condensate is directed into the spray film evaporator and the feed or condensate is sprayed onto the outer surfaces of a bundle of tubes. This results in the feed or the condensate being vaporized and producing a vapor that can be utilized as a heat source for other processes in a pulp mill.

Abstract: It is described a process for thermal hydrolysis and team explosion of biomass, said method comprising the steps of: (i) leading the biomass approximately continuous to a first preheating step and preheat the biomass, (ii) leading the preheated biomass into at least two reactors sequentially, (iii) heating and pressurising the reactor by addition of steam, (iv) keeping the reactor(s) at a certain temperature and pressure for a certain time, (v) leading the heated and pressurized biomass from the reactor(s) to a first pressure relief tank without any substantial pressure reduction and quickly relief the pressure of the biomass by means of a nozzle, in order to disintegrate the biomass, (vi) leading the biomass from the first pressure relief tank to a second pressure relief tank having a lower pressure than the pressure of the first pressure relief tank, (vii) leading the so treated biomass to a downstream facility for subsequent treatment. The invention also comprises a device for thermal treatment of biomass.

Abstract: The present invention relates to a process and a device for evaporating liquids, for example black liquor from cellulose cooking, which contain solid and dissolved substances which are to be concentrated. The liquid is heated to close to boiling temperature in a heat exchanger (1) of the falling-film type. The process is characterized in that the pressure on the liquid side in the falling-film heat exchanger (1) is kept so high that boiling does not take place in this heat exchanger and in that the evaporation takes place, by means of flashing, in a separate expansion tank (7) that has a lower steam.

Abstract: The present invention relates to a method and an arrangement for use in connection with the combustion of black liquor. In the method the black liquor is concentrated in a multi-effect evaporation plant in order to obtain black liquor at a suitable dry-solids content for combustion and to generate vapor. The concentrated black liquor is taken to be combusted in a recovery boiler, into which combustion air is fed at several levels for the combustion process. It is a characteristic feature of the invention that the air fed to at least one air level is preheated by using vapor generated in the concentration of the black liquor as heat source.

Abstract: This invention refers to a method for producing pulp in an alkaline digesting process comprising the following steps: charging lignocellulosic material to a digester system; pre-treating said lignocellulosic material with an impregnation liquor and subsequently with a hotter liquor containing black liquor, simultaneously displacing spent liquor; heating and cooking said lignocellulosic material to produce cooked lignocellulosic material and cooking liquor; displacing a portion of said cooking liquor at cooking temperature from said digester to a first section by supplying a washing liquid; further displacing a second portion of displaced liquor from said digester system to at least a second section by supplying further washing liquid until the temperature of said second portion of displaced liquor drops to a temperature of at least about the boiling point of said cooking liquor at atmospheric pressure, said second portion of displaced liquor having a dry solids content substantially lower than the initial dry

Abstract: Method is disclosed for treating wood chips including a heater for preheating the wood chips in the presence of steam, a beater to mechanically process the wood chips into wood fibers, a cyclone for separating the wood fibers from steam and volatile organic substances produced in the beater, a blower line for transporting the wood fibers, steam and volatile organic substances from the beater to the inlet of the cyclone, a drying conduit connected to the lower outlet of the cyclone for carrying wood fibers therefrom, a sluice valve associated with the lower outlet of the cyclone for controlling the removal of the wood fibers from the cyclone, and a processing conduit connected to the upper outlet of the cyclone for the steam and the volatile organic substances whereby the volatile organic substances separated in the cyclone can be separated and heat associated with the steam separated in the cyclone can be recovered.

Abstract: A method and system for handling foul condensate containing Hazardous Air Pollutants (HAPs) in a cellulose pulp mill has enhanced energy efficiency and lower cooling water usage, while complying with the Cluster Rules and other environmental regulations. The condensate is fed countercurrently to stripping vapor in the stripping column to produce a HAPs vapor and a clean condensate. Part of the clean condensate is fed from the stripping column reboiler, and the HAPs-rich vapor is directed to the reboiler to at least partially condense while vaporizing the clean condensate into the clean vapor (stripping vapor). The pressure of the stripping vapor is increased, such as utilizing a steam ejector, to about 0.1-30 psig and then is used as the stripping vapor in the stripping column. The non-condensed HAPs-rich vapor is fed to an external condenser, and the dirty condensate from the external condenser and the dirty condensate from the reboiler, are returned to the stripping column.

Abstract: A process for evaporating spent liquor or other waste liquids from cellulose cooking, The evaporation is performed in a multiplicity of evaporators which are coupled in series and in which the evaporation is driven using the liquor steam. The condensates from the steam are divided, in one of more effects, into at least two fractions with respect to purity. The parer fraction from one effect is conveyed, at a high level, into a subsequent effect in the direction of movement of the liquor, while the dirtier fraction is conveyed, at a high level or at the very top, into a preceding effect in the direction of movement of the liquor.

Abstract: A method of treating cellulose pulp mill condensates having an MeOH content using an evaporator and a steam stripper having a reboiler, comprising: (a) Collecting a feed liquor stream having at least 50% of the pulp mill MeOH. (b) Feeding the feed liquor stream to the evaporator having at least two heating element sections separated on a motive steam side. (c) Evaporating the liquor in the evaporator to produce a vapor containing at least 40% of the at least 50% of the pulp mill MeOH. (d) Compressing the vapor from (c) to increase the vapor pressure. (e) Using the vapor from (d) as condensing heating media in (c) for the evaporation in a first heating element section of the evaporator and venting a portion of the vapor through the first heating element section. (f) Compressing the vented vapor from the heating elements of the evaporator from (e) to increase the vapor pressure to be used as heating media in the reboiler.

Abstract: Volatile compounds, such as methanol, are separated from secondary condensates formed in multi-effect evaporation of waste liquor, such as black liquor, from cellulose pulp processes. The condensable secondary vapor is condensed into first and second condensate flows, the first of which, smaller in volume, contains the majority of the volatile compounds condensed in the evaporating effect. The first condensate flows from one or more first evaporation effects, and/or condensers of the evaporation plant, are directed for cleaning into a first steam stripping column. At least some of the second flows are directed to a second steam stripping column to be recovered as very clean condensate, cleaner than the condensate flow from the first stripping column and typically have a methanol concentration of less than 25 ppm, preferably about 10 ppm or less.

Abstract: A process and apparatus provide for the evaporation of spent liquors in several stages, and recovery of volatile substances from spent liquors of organic solvent pulping processes. The recovery system for volatiles is integrated with the evaporation of spent liquors. Heating condensation is carried out in each evaporator effect on several heat surfaces separated from each other. Pure water, vapor condensate, or steam may be injected to the warmer side of an evaporator effect in order to increase the condensing temperature of the vapor. The volatiles are typically alcohols (methanol and/or ethanol) used as the cooking liquor in organic solvent pulping.

Abstract: A method and apparatus for deaerating a suspension of solids in a liquid such as, for instance, papermaking stock. The suspension is flashed in a vacuum tank connected to a condenser. The vapor released when the suspension is flash cooled in the tank is condensed into an absorption liquid having a higher temperature but a lower vapor pressure than that of the released vapor on a heat exchange surface of the condenser. The flash cooled suspension is used as the cooling medium in the condenser. The diluted absorption liquid is regenerated in an evaporator and recirculated to the condenser. The vapor released in the evaporator can be condensed to heat the suspension further or for other suitable heating purposes.

Abstract: The number 2 flash tank of a black liquor energy recovery system associated with a continuous pulp digester is eliminated, and other advantages are obtained. After flashing in the number 1 flash tank, concentrated black liquor passes to a multiple effect evaporator system as the heating fluid supplied to the last effect. The heated black liquor passes in heat exchange relationship with excess make-up liquor from the high pressure feeder circulation system and/or with portions of the extracted black liquor that have had more of their content removed, the heated black liquor effecting evaporation of the excess make-up liquor and/or portions of the black liquor. Steam from the steam relief of the steaming vessel may be used as a secondary heating fluid source for the first effect.

Abstract: Apparatus for manufacturing pulp fiber from lignocellulose-containing material is disclosed, including a preheater, a defibrator with a pressurized housing, a conveying screw to convey the preheated lignocellulose-containing material from the preheater to the defibrator, a horizontal separator, a blow pipe for transferring the defibrated lignocellulose-containing material and steam from the defibrator to the horizontal separator, in which the horizontal separator includes a pulp outlet, a steam outlet, and a screw conveyor which includes screw threads which have a screw thread angle which substantially corresponds to the angle at which the blow pipe enters the horizontal separator. The screw conveyor in the horizontal separator feeds the defibrated lignocellulose-containing material from the blow pipe to the pulp outlet in the form of a pulp plug which maintains the pressure within the separator, and a steam transfer line is provided transferring the separated steam from the steam outlet to the preheater.

Abstract: There has been provided a system and apparatus for recovering turpentine from a thermomechanical pulping process for making paper, which thermomechanical pulping process utilizes a plug screw conveyor for squeezing and feeding pulp chips. The thermomechanical pulping process is conventional. The liquid effluent from said plug screw conveyor contains an appreciable amount of turpentine. The liquid effluent is collected under superatmospheric pressure and flashed into vapor/liquid separator by releasing the pressure on the liquid. This vapor is condensed in a suitable condenser and the condensate collected in a decanter where the turpentine collects as a separate phase and the water also as a separate phase. Condensate from various vents in the conventional thermomechanical pulping process may be collected for more nearly compelete removal of turpentine and other oleoresinous components.

Abstract: In a refiner (40) with two opposed discs (47,48) rotatable relative to each other fibre pulp is manufactured from lignocellulose-containing material. The material is advanced in a channel comprising a plug pipe (20), through which the material is fed in compressed state, and a steam screen pipe (32) for discharging steam. The steam screen pipe (32) is located directly after the plug pipe (20) and has a cross-sectional area, which slightly exceeds that of the plug pipe in order to allow a limited expansion of the material plug. The steam is thereby allowed to flow through the material, at the same time as the material plug prevents clogging of the apertures (37,39) of the steam screen pipe.

Abstract: The present invention relates to a method and apparatus for evaporating waste liquor produced when cooking fibrous material containing cellulose in a continuous pulp digester. In the continuous cooking process, fibrous material is heated to the process temperature by direct or indirect vapor heating in the digester at an increased pressure. The invention especially relates to digesters, in which fibrous material is heated directly with vapor.

Abstract: A method for recovering turpentine and heat in a TMP process in which woodchips are heated in a preheater and the vent vapors from the preheater are passed to the condensing vapor zone of an evaporator condenser-reboiler having a condensing vapor zone and a boiling liquid zone. A major portion of the vent vapors are condensed so as to produce a turpentine-lean condensate and turpentine-rich vapor phase. The turpentine-rich vapor phase is withdrawn from the evaporator and passed to a turpentine condenser where it is cooled by indirect heat exchange contact with a cooling liquid to produce a condensate containing immiscible turpentine and aqueous phases. The turpentine and the aqueous phases are separated.

Abstract: The invention relates to a process of increasing the solids content of black liquor at its recovery in a sulfate pulping process. According to the invention, the liquor is first heated at a pressure which is so high that no boiling occurs at the heating temperature, after which the liquor is led to a tank where its pressure is released to a value below the saturation pressure of steam at the relative temperature of the liquor such that water is evaporated. The liquor thus concentrated can be led to the liquor combustion in the recovery process.

Abstract: The invention relates to a method for evaporation of spent liquor by heat from a blow condenser where blow steam from a pulp cooker is condensed in a direct condenser connected with a hot water accumulator. Spent liquor heated indirectly by hot water from the accumulator is brought to expand and released expansion vapor is used as a heat medium in a following evaporation stage. The apparatus comprises a heat exchanger, at least one flash tank and at least one evaporation unit, the heat exchanger being disposed to receive hot water from the upper part of the accumulator and to return it to its lower part and thus heat the spent liquor, and the flash tank being disposed to receive spent liquor heated in the heat exchanger and to release liquor vapor and spent liquor to the evaporation unit.

Abstract: Calcium containing sulphate spent liquor is deactivated by means of heating. Spent liquor is heated by means of direct condensing in a flash-steam-system. Liquor vapors generated during expansion of the already deactivated spent liquor are used for heating the spent liquor. Spent liquor is led to a retention tank through n+1 in series connected direct condensers (DK I-DK V) and from the retention tank through n in series connected flash tanks (FT I-FT IV) disposed counter-currently to the direct condensers. In the last one of the direct condensers (DK V) the liquor is heated by means of externally supplied steam; in all others (DK I-DK IV) by means of expansion vapor.

Abstract: A method and system for efficient heat recovery during the production of mechanical pulp treats the process steam inherently produced during the production of mechanical pulp to maximize the energy content of clean steam produced. Comminuted cellulosic material is refined in one or more refiners, and the mixture of mechanical pulp and process steam from the refiner is separated into process steam and pulp flows by a cyclone. The process steam is passed to a scrubber, and then to an inlet of a reboiler (steam transformer) which produces clean steam and discharged flow-through process steam. The conduit between the cyclone and the scrubber is open so that the pressure of the process steam before it enters the reboiler is not significantly affected; a buffer may be provided in the conduit, however, to damp process steam pressure variations.

Abstract: In the production of mechanical pulp, a refiner (defibrator) is driven by a steam turnine. The steam supply for the turbine comprises process steam generated in the refiner during the refining action, which steam is preferably passed through a reboiler. Some make-up energy is necessary to provide all of the power for driving the refiner, the make-up energy being preferably provided by clean steam from an accessory source introduced to the turbine by a steam ejector. A portion of the process steam, and the steam discharge from the turbine, can be used for presteaming the chips (comminuted cellulosic fibrous material) before introduction into the refiner. Any condensate from the turbine may be fed to the reboiler. Reduction gears are provided between the turbine and the refiner drive shaft so that the refiner is driven at optimum rpm for the particular material being treated.

Abstract: In the production of mechanical pulp a refiner (defibrator) is driven by a steam turbine. The steam supply for the turbine comprises process steam generated in the refiner during the refiner action, which steam is passed through a reboiler and then superheated, in a superheater or economizer, before being supplied to the turbine. A boiler comprises a secondary source of steam and that steam too is introduced to the steam turbine, either directly or after passage through another turbine which powers an electric generator. The off-gases from the boiler may drive a gas turbine. All the components may be mounted on a train, and the gas turbine may power the locomotive for the train. The gas turbine can also power an air compressor providing compressed combustion air to the boiler.

Abstract: A process is provided for inexpensively producing high yield mechanical cellulose pulp having good paper properties, which comprises preheating particulate lignocellulosic material; defibrating the preheated material under a superatmospheric steam pressure within the range from about 2 to about 4.5 bar above atmospheric pressure in a disc refiner under conditions such that steam is generated during the defibration; continuing the defibration until a cellulose pulp is obtained having a freeness within the range from about 300 to about 700 ml CSF; flash drying the defibrated cellulose pulp while maintaining a superatmospheric steam pressure within the said range during the drying; withdrawing steam generated during the defibration and passing it in indirect heat exchange with steam utilized in the flash drying, so as to utilize in the drying at least 30% of the heat content thereof; and then removing and baling the flash-dried cellulose pulp.

Abstract: A process is provided for heating up wood chips in one or more stages at progressively higher temperatures prior to steaming and pulping in an economical manner at a considerable cost saving; heating the chips in at least a first preheating stage directly with moisture-saturated hot air, optionally admixed with inert gas, having a temperature within the range from about 55.degree. to about 99.degree. C., preferably from 70.degree. to 90.degree. C., having been brought to that temperature in a heat exchanger with hot water or air heaters with waste gases, such as gases drawn at different levels from an evaporator, for example, a Lockman pre-evaporator column.

Abstract: A method and apparatus in defibration of wood chips or similar vegetable material for conveying in steam pulp produced in a refiner (2) to a separator (7) for separating steam and pulp. The separator is bounded against the atmosphere and is kept pressurized by steam, while a limited amount of excess steam is led off. A flow of steam liberated from the pulp is taken from the separator and given an increased pressure for utilization in extracting pulp from the refiner. The steam flow is hereby led through the refiner and further to the separator, whereby the pulp is transferred to the separator by the steam which thus circulates to a considerable extent, said steam having been given the higher pressure either in the refiner itself, by means of pressure increasing means (19) therein, or upstream of the refiner in a separate pressure increasing means (11).

Abstract: A process is provided for the chemical refining of cellulose pulp which comprises, in sequence, the steps of:(1) impregnating the cellulose pulp with refining chemicals in an amount selected to effect chemical modification of the pulp;(2) adjusting the pulp consistency to within the range from about 30 to about 70%; and(3) passing the pulp in turbulent flow through an elongated reaction zone from one end to another end thereof in a gaseous atmosphere consisting essentially of steam and preferably containing less than 1% by volume of oxygen at a superatmospheric pressure within the range from about 5 to about 400 kPa and a temperature within the range from about 100 to about 150.degree. C. at which the chemical modification proceeds without a mechanical working sufficient to change the degree of beating of the pulp by more than about 2.degree.

Abstract: Method and apparatus for producing pulp from moisture-containing lignocellulosic material, such as wood chips, which is ground in a grinding space defined between a pair of grinding discs which rotate relative to one another in an environment of pressurized steam generated during the grinding process, in a closed housing. The ground fiber or pulp discharged from the grinding housing is propelled by the accompanying steam into a cyclone, where the ground pulp is separated from the steam for further treatment, while the steam is recycled for further use in the pulping process. The pressure in the cyclone is so controlled that a pressure is maintained therein which is substantially equal to a pressure drop which is sufficient merely to maintain the propellant force of the steam to convey the ground pulp from the grinding housing to the cyclone while discharging the separated steam and recycling it for further use in the pulping process.

Abstract: A process is provided for preparing groundwood pulp from debarked pulpwood logs, which comprises grinding the logs under a superatmospheric pressure of a gas selected from the group consisting of steam, air, and steam and air, while continuously supplying thereto water comprising spent bleaching liquor at a temperature of at least 70.degree. C. and forming a pulp suspension in the resulting aqueous liquor; centrifugally separating steam from the pulp suspension and using the separated hot steam to heat spent bleaching liquor supplied for the grinding; thickening the pulp suspension to a concentration within the range from about 5 to about 40% and supplying water separated therefrom to the grinding; diluting the pulp suspension to a concentration within the range from about 0.5 to about 4.

Abstract: A device for evacuating blow-back steam in a pulp refining apparatus in which lignocellulosic pulp stock is ground in an environment of superatmospheric steam in a grinding space defined between a pair of grinding members which rotate relatively to one another in a closed housing having a feed-in opening into which the pulp stock is advanced by means of a feed screw which rotates within a feed-in passage. A jacket having a perforate wall is arranged about the feed-in passage for receiving the blow-back steam separated from the pulp stock, and which steam is evacuated therefrom through a conduit connected to the jacket. The feed screw rotates in close proximity to the perforate wall to maintain it free of pulp stock particles.