Abstract: A method for washing a fibrous suspension. The fibrous suspension is dearated with a deaerating centrifugal pump as it is pumped into the washing zone. The washing water is also dearated with a deaerating centrifugal pump.

Abstract: A transfer and nursing system for a patient, including a lifting frame having a pair of opposing sides formed by profile bars, the profile bars each having at least two grooves running longitudinally therein. A bearing arrangement is provided for suspending the lifting frame. A lifting sheet and an underlay element are detachably securable to the profile bars of the lifting frame by an arrangement for detachably securing the lifting sheet and the underlay sheet in the grooves of the profile bar so that a plurality of lifting sheets and underlay sheets can be attached to the frame.

Abstract: A method for treating gases and solids in a fluid bed, the fluid bed reactor substantially comprising, regarded downstream, a mixing chamber, a riser pipe and a cyclone with a solids return pipe to the mixing chamber, the gases being introduced into the mixing chamber at a gas rate immediately before the inlet port of the mixing chamber of more than 35 m/sec.

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 of cooling hot flue or process gases containing halogenous compounds in two successively located circulating fluidized bed reactors. In the first reactor the gases are cooled to a temperature of >400.degree. C. In the second reactor the gases are rapidly cooled to below a temperature zone of 250.degree.-400.degree. C. In the first reactor the gases are brought into contact with a catalytic material capable of destroying polyhalogenous compounds. A retention time of 1-10 seconds, preferably 2-5 seconds, is provided for the gases in the first reactor.

Abstract: An apparatus provides purification of waste gases by adding particles of reagent and/or absorbent, which react with the pollutants in the waste gases, to the gases, and by introducing the gases into a wetting reactor for activating the reagent or absorbent contained in the gases. Gases are conveyed to at least two levels in the reactor through inlets so that a first portion of the gases is introduced into a wetting zone and a second portion of the gases below the wetting zone. A high density of particles is maintained in the wetting zone by recycling to the wetting zone particles separated from the gas above the wetting zone.

Abstract: The amount of N.sub.2 O in flue gases discharged from a fluidized bed combustion system is minimized by adding an N.sub.2 O decomposing catalyst in a reactor stage downstream of the combustor. The catalyst preferably is a calcium based sorbent, such as CaO or or limestone, although NiO and other catalysts also may be utilized. Typically, the N.sub.2 O decomposition takes place without increasing the temperature of the flue gases above the 700.degree.-1000.degree. C. level that exists combustor. However, under some circumstances, if a second fluidized bed is provided as the reactor stage, additional fuel and oxygen can be added to increase the temperature of the flue gases to insure that it is over 800.degree. C. After N.sub.2 O decomposition, the flue gases may be passed through pressurized filter tubes, or through a superheater, economizer, air preheater, optional cyclone separator, and baghouse filter.

Abstract: A method and apparatus for generation of electricity by pressurized gasification of black liquor in a combined power plant. The gases produced in the gasification of black liquor are purified and introduced into a gas turbine for generating electricity. From the turbine, the gases are conducted to a waste heat boiler. High pressure steam generated in the waste heat boiler and or auxiliary boiler is introduced into a steam turbine to such an extent that the exhaust steam from the steam turbine covers the steam and heat demands of the pulp mill. The excess steam is introduced into the gas turbine or the combustor thereof for increasing the generation of electricity.

Abstract: White water from a paper machine is treated in an improved fiber recovery process, i.e., the "save-all" process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Abstract: Sulphur dioxide is separated from the flue gases of a cellulose pulp mill by absorbing it into a sodium sulphite solution. Sulphur dioxide is regenerated from the sodium bisulphite solution produced by an evaporation-crystallization method utilizing thermo-compressor evaporation technique. A lamella evaporator is utilized as the evaporator-crystallizer, the evaporator being divided into separate compartments for ease of cleaning the lamella surfaces. The recovered concentrated sulphur dioxide can be used wherever desired, for example for the production of chlorine dioxide.

Abstract: Black liquor from a cellulose pulp processing plant is treated, including by using a direct contact (cascade) evaporator, without need for oxidizing the black liquor, without substantial sulphur emissions at the cascade evaporator, and by maximizing the solids content of the black liquor so that the loss of heating value of the black liquor is minimized. The black liquor is heated under temperature and time conditions sufficient to drive off most of the organic sulphur compounds as off gases, which gases are converted primarily to methane and hydrogen sulfide, with the methane separated by selective absorption in white liquor. The black liquor is then stripped of most remaining sulfur by bringing it into stripping contact with flue gases from the recovery boiler, the flue gases taken from downstream of the direct contact evaporator.

Abstract: A reactor chamber of a fluidized bed reactor has an internal circulation of particles. Larger recirculated particles are prevented from contacting heat transfer surfaces by classifying particles adjacent the bottoms of the reactor chamber using a particle chamber having a barrier wall with holes or slots of a maximum dimension of less than about 30 mm. The heat transfer surfaces may be disposed in the particle chamber. Larger particles flow down the walls of the particle chamber into the reactor chamber, and some fine particles within the particle chamber are preferably recirculated back to the fluidized bed. The barrier wall is preferably the top wall of the particle chamber, and may be refractory lined with furrows, and/or may be formed of water tubes connected together by fins, with the holes or slots formed in the fins.

Abstract: The amount of N.sub.2 O in flue gases discharged from a fluidized bed combustion system is minimized by effecting vigorous and intimate mixing of the flue gases (with entrained particles) from a fluidized bed by increasing the velocity of the flue gases and then decreasing the velocity from the increased level, introducing a N.sub.2 O decomposing catalyst into the flue gases and particles immediately after increasing and decreasing of the velocity, and mixing the N.sub.2 O catalyst with the flue gases and particles, to effect decomposition of the N.sub.2 O. The catalyst is a calcium based sorbent, such as CaO or limestone, although and other catalysts also may be utilized. Normally the decomposition takes place without increasing the temperature of the flue gases. The increase in velocity is achieved by providing a constriction in the combustor vessel. The interior of the combustor vessel is lined with erosion resistant and thermal insulating material.

Abstract: In association with a circulating fluidized bed reactor, a bed of particles is established in the return duce for particles from the particle separator to the combustion chamber. Inlet openings extend from the bed of particles into the combustion chamber, and the height of the particle bed is maintained above the inlet openings a sufficient distance to form a gas seal. The particles in the bed are fludized, and also transporting nozzles are arranged at different levels for transporting the particles from the bed through the inlet openings into the combustion chamber. Heat exhangers (e.g. superheaters) may be provided in the bed to recover heat from the particles.

Abstract: Chemicals are recovered during the production of cellulose pulp by forming two different sulfidity melts in two different sections of a soda recovery boiler, and then producing cooking liquors from different melts in dissolving tanks. The liquors may be causticized and/or oxidized, or may be utilized uncausticized. Uncausticized green liquor having a sulfidity of about 70-90% may be used early in a kraft cooking cycle, followed by treatment with low sulfidity oxidized and causticized white liquor. In the continuous digestion of cellulosic pulp, oxygen may be added to the recirculation loops below the black liquor withdrawal to enhance the alkalinity of the slurry and to assist in delignification. Oxidized cooking liquor with low sulfidity can be added to oxygen bleaching and alkali extraction stages downstream of the digester, and a portion of the high sulfidity cooking liquor can be used to produce acid used in an ozone bleaching stage.

Abstract: An apparatus for treating pulp includes an outer casing, a stationary screen surface mounted in the outer casing. A conduit introduces pulp into the interior of the screen surface. An annular space is defined between the screen surface and the casing for receiving the fraction passing through the screen surface. A feed screw is rotatably mounted in the interior of the screen surface. The feed screw extends vertically or is to some extent inclined relative to the vertical direction. The feed screw includes a shaft and pulp conveying blades. The periphery of the feed screw is provided with a nozzle conduit extending substantially parallel to the shaft and located close to the screen surface for spraying washing liquid to the screen surface. The apparatus is especially suitable for screening and/or thickening of fiber suspensions in the wood processing industry.

Abstract: In a fluidized bed reactor particles are internally circulated, moving down the walls forming the reactor chamber. A particle chamber having a particle gathering top wall with a horizontal projection area A is disposed in the downward flow of particles. Openings (e.g. holes or slots) with a controlling dimension of about 30 mm or less are provided in the top wall, the openings having total open area B less than half the area A. Heat transfer surfaces may be disposed in the particle chamber.

Abstract: A method for treating gases and solids in a fluid bed, the fluid bed reactor substantially comprising, regarded downstream, a mixing chamber, a riser pipe and a cyclone with a solids return pipe to the mixing chamber, the gases being introduced into the mixing chamber at a gas rate immediately before the inlet port of the mixing chamber of more than 35 m/sec.

Abstract: A method and apparatus are provided for analyzing the elemental constituents of fluid streams in the cellulose pulp industry, such as liquid with dissolved solids for treatment of cellulose pulp or from the treatment of cellulose pulp, or liquid slurries including comminuted cellulose material. Continuous on-line elemental analyses are made of one or more such fluid streams, and at least the partial elemental make-up (either material, or of elements added for marking) of the streams determined. Then one or more processes for acting on the fluid streams are controlled to optimize the processes as a result of the analyses made. The invention is particularly useful in the continuous on-line analysis of black liquor utilizing prompt gamma neutron activation analysis, and controlling the operation of an evaporator or recovery boiler.

Abstract: Sodium sulphate and/or sodium carbonate containing material from a cellulose pulp mill, such as fly ash from a recovery boiler, or a by-product from a chlorine dioxide production plant, is brought into contact with a a gas containing hydrocarbons and/or hydrogen sulphide which chemically reacts with the material to produce sodium sulphide. Preferably the gas contains one or both of ethene and hydrogen sulphide. The sodium sulphide produced is used to effect sulphate cooking of cellulose pulp. The gas may be brought into contact with the melt of a soda recovery boiler to increase its sulphidity, either prior to, after, or simultaneously with bringing the gas into contact with the material. The sources of the fly ash and melt may be a soda recovery boiler combusting black liquor under oxidizing conditions.