Abstract: The method is for influencing the flow from a strainer construction in a continuous digester. In order to avoid clogging of the withdrawal compartment in the strainer construction, an additive that counteracts precipitation processes is added directly to the withdrawal compartment while the cooking fluid is withdrawn from the withdrawal compartment. The addition of chemicals can take place at the same time as the withdrawn cooking fluid is withdrawn from the digester and the strainer construction, or while the withdrawn cooking fluid is fully or partially re-circulated back to the withdrawal compartment.

Abstract: The withdrawal screen section is for impregnation of chips during the manufacture of chemical pulp. Chips are steamed and impregnated in a low pressure impregnation vessel using pressurised hot spent cooking liquor BL. The spent cooking liquor produces most of the steam BLST, necessary for steaming the chips. To reduce the need for adding fresh steam for chip steaming is a first withdrawal section in the impregnation vessel modified to be used both as a flash tank for warm pressurised wash filtrate and improved wash-out feature for the spent impregnation liquid behind the screen in the withdrawal section. The withdrawal volume is arranged with an upper part located above the liquid level LIQLEV of the impregnation vessel. Additional pressurised warm wash liquor REC1 is added to the withdrawal volume and flashed off steam is led in a steam duct to the chip volume above the liquid level.

Abstract: The method and an arrangement are for the improvement of a wash after completed digestion in a continuous digester for the production of cellulose pulp. The softened chips are exposed to a radially directed displacement wash after they have passed the rotating bottom scraper. The displacement wash has been established in the flow of digested softened chips through the outlet tap before the softened chips are defibrated by the fall in pressure across the blow-valve that is arranged after the digester.

Abstract: The method and an arrangement are for the improvement of a wash after completed digestion in a continuous digester for the production of cellulose pulp. The softened chips are exposed to a radially directed displacement wash after they have passed the rotating bottom scraper. The displacement wash has been established in the flow of digested softened chips through the outlet tap before the softened chips are defibrated by the fall in pressure across the blow-valve that is arranged after the digester.

Abstract: The arrangement and method for the steam pre-treatment of chips during the production of cellulose pulp avoids the blow-through of gases in the steam pre-treatment vessel. This prevents foul-smelling gases from being released into the atmosphere. The inlet of the vessel has an inclined feeder device in a feeder-housing. In the event of the initiation of the risk for blow-through of steam, the feeder housing is sprayed with cooling liquid in order to increase condensation capacity of the chips being fed into the vessel. Ultimately the feeder housing is filled with liquid that establishes a liquid lock, and preferably at the same time as the feeder drive (M) is shut off. This avoids the emission of gases from the chip bin when interruptions in the process occur so that the release of odors into the surroundings is minimized.

Abstract: The device is for the dilution of dewatered cellulose pulp that maintains a consistency of 20-30% or greater. By shredding of the pulp to a finely divided dry-granulate, dilution to a homogeneous consistency in the medium consistency range can take place exclusively through hydrodynamic effects from the addition of dilution fluid. The dilution fluid is added to granulate at a position at which granulate is in free fall in a standpipe and above a level Liqlev of diluted pulp in the standpipe. A number of nozzles are arranged around the periphery of the stand pipe, directed in towards the center of the stand pipe, obliquely downwards in the direction of fall of the granulate. It is possible through this simplified procedure to avoid completely the conventional dilution screws, and this reduces the investment costs and operating costs, while at the same time unnecessary mechanical influence of the pulp fibers can be avoided.

Abstract: The method and a device is for the dilution of dewatered cellulose pulp that maintains a consistency of 20-30% or greater. By shredding of the pulp to a finely divided dry-granulate, dilution to a homogeneous consistency in the medium consistency range can take place exclusively through hydrodynamic effects from the addition of dilution fluid. The dilution fluid is added to granulate at a position at which granulate is in free fall in a standpipe and above a level Liq.sub.LEV of diluted pulp in the standpipe. A number of nozzles are arranged around the periphery of the stand pipe, directed in towards the centre of the stand pipe, obliquely downwards in the direction of fall of the granulate. It is possible through this simplified procedure to avoid completely the conventional dilution screws, and this reduces the investment costs and operating costs, while at the same time unnecessary mechanical influence of the pulp fibres can be avoided.

Abstract: The digester screen is for a continuous digester in which cooked cellulose pulp is produced. The digester screen has a number of screen bars arranged vertically in the continuous digester that have withdrawal slots (S) between the fixed screen bars through which withdrawal slots cooking fluid can be withdrawn from the column of pulp (P) of the digester. By having every second screen bar fixedly arranged and recessed a distance (D) relative to the neighboring screen bar an increased withdrawal capacity for the screen is obtained.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. The outlets of the pumps are combined at a merging point before a common transfer line extends to the top of the digester. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The method is for influencing the flow from a strainer construction in a continuous digester. In order to avoid clogging of the withdrawal compartment in the strainer construction, an additive that counteracts precipitation processes is added directly to the withdrawal compartment while the cooking fluid is withdrawn from the withdrawal compartment. The addition of chemicals can take place at the same time as the withdrawn cooking fluid is withdrawn from the digester and the strainer construction, or while the withdrawn cooking fluid is fully or partially re-circulated back to the withdrawal compartment.

Abstract: A method for the impregnation of untreated chips during the manufacture of chemical pulp. The untreated chips are fed without preceding steam treatment into an impregnation vessel that has an upper part with a first area (A1) and a lower part with a second area (A2) that is larger than the first area (A1) by a factor of at least ?{square root over (2)}. The chips establish in the upper part a level of chips that is located at a level (h) above a level of fluid consisting of liquor. The chips after passage of the upper part pass through a transitional part, where an increase in area from the first area (A1) to the second area (A2) takes place, and it is here that the angle of repose of the chips is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. The transfer to the top of the digester takes place without a conventional top separator. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel in the bottom of a pre-treatment vessel and a liquid level of at least 10 meters is established. The system makes it possible to provide a feed system with an improved accessibility and more reliable operation, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. Each pump has its own independent transfer line extending to the top of the digester. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel and a stirrer is provided in direct connection to inlets to pumps. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The method and a device is for the dilution of dewatered cellulose pulp that maintains a consistency of 20-30% or greater. By shredding of the pulp to a finely divided dry-granulate, dilution to a homogeneous consistency in the medium consistency range can take place exclusively through hydrodynamic effects from the addition of dilution fluid. The dilution fluid is added to granulate at a position at which granulate is in free fall in a standpipe and above a level LiqLEV of diluted pulp in the standpipe. A number of nozzles are arranged around the periphery of the stand pipe, directed in towards the centre of the stand pipe, obliquely downwards in the direction of fall of the granulate. It is possible through this simplified procedure to avoid completely the conventional dilution screws, and this reduces the investment costs and operating costs, while at the same time unnecessary mechanical influence of the pulp fibres can be avoided.

Abstract: The digester screen is for a continuous digester in which cooked cellulose pulp is produced. The digester screen has a number of screen bars arranged vertically in the continuous digester that have withdrawal slots (S) between the fixed screen bars through which withdrawal slots cooking fluid can be withdrawn from the column of pulp (P) of the digester. By having every second screen bar fixedly arranged and recessed a distance (D) relative to the neighboring screen bar an increased withdrawal capacity for the screen is obtained.

Abstract: The method and arrangement is for the feed of a chips suspension from one vessel to a subsequent digester in a continuous cooking process for the production of chemical cellulose pulp. The vessel has an inlet defined therein for the input of chips and an outlet defined therein for the output of a chips suspension. The chips suspension in the vessel has a first fluid/wood ratio established above a second fluid/wood ratio that is established at the bottom of the vessel. The second fluid/wood ratio is at least as great as, preferably greater than, the first fluid/wood ratio. After the output of the chips suspension from the vessel and before the chips suspension is placed under pressure for onwards transport to a subsequent digester, a fraction of fluid is withdrawn from the chips suspension, whereby a third fluid/wood ratio is established in the chips suspension.

Abstract: A procedure for the continuous cooking of chemical pulp, comprising an impregnation vessel 101 and a digester 102. The chips are impregnated in the impregnation vessel 101and are fed after impregnation together with circulation fluid through a transfer line 103 to a top separator 105 on the digester 102 in order to be cooked. A fraction of the circulation fluid is withdrawn at a top separator 105 and returned to the bottom of the impregnation vessel 101 via a return line 106. Black liquor is withdrawn from the digester via a black liquor line 108 to the impregnation vessel 101. The invention is characterized in that a heat exchanger 107is arranged between the return line 106 and the black liquor line 108. The heat exchanger 107 allows the exchange of heat between the two lines, but does not allow the exchange of fluid. The temperature of the black liquor in the black liquor line 108 after passing through the heat exchanger 107 has been cooled by 10-15 ° C.

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, such that as large a fraction as just over 20% of the total oxygen added is dissolved in the fluid phase, and such that the amount of oxygen in the fluid phase is maintained at a high level throughout the complete high pressure section. By the establishment of retention times between the remixing operations with successively increasing retention times, while retaining a high pressure, an optimal adaptation of the remixing is obtained at the time at which a certain fraction of the oxygen dissolved in the fluid phase has been consumed.