Abstract: In a process for the extraction of celluloses from lignocelluloses, the extraction is carried out by means of heating with aqueous acetic acid under pressure and the addition of formic acid, whereby there is obtained a cellulose with a very low residual lignin content, which can be bleached with ozone and peracetic acid to high grades of white, and acetic and formic acid are recovered by means of distillation, so that waste waters do not, therefore, accumulate.

Abstract: Paper web formation analyzers can be employed both on operating paper machines at high speed and on cut samples as a desk top unit, so as to unify formation evaluation for both situations.

Abstract: A method for the manufacture of non-chlorine bleached pulp, from alkaline digested cellulose pulp, wherein a suspension of the cellulose pulp is subjected to a series to oxygen gas delignification (O), treatment with complexers (Q) and bleaching with non chlorine-containing oxidative bleaching agents (O,P,Z). The various treatment stages interspersed with washing and/or reconcentration of the cellulose pulp in at least one stage, in conjunction with which a suspension liquid is conveyed essentially in strict counter-current, with the result that the pulp manufacturing process is essentially totally closed with regard to the liquid circuit.

Abstract: A method for use in a batch digesting process is provided which includes the removal of a portion of the hot cooking liquor from the digester prior to the cook creating a liquid-vapor interface in the digester followed by the removal or purging of the vapors disposed above the liquid-vapor interface and the reduction of the pressure in the digester to about the saturation pressure of the hot cooking liquor. The inclusion of these steps in the process helps to eliminate a coating on the pulp fibers which has been found to inhibit the bleachability and runability of the fibers. Accordingly, an apparatus and method for the batch digesting of pulp fibers is provided which provides pulp fibers having improved bleachability and runability characteristics.

Abstract: An enzymatic process for treating coarse pulp with an enzyme having cellobiohydrolase activity to reduce the specific energy requirements of the pulp and improve the properties of the pulp. Cellobiohydrolase enzymes isolated from the species Trichoderma, Aspergillus, Phanerochaete, Penicillium, Streptomyces, Humicola or Bacillus can be used.

Abstract: A pressure vessel 1 with an output arrangement 5, primarily for use with pulp bleaching using peroxide at high temperature and high pressure, comprising a pressure vessel housing 1, a first end 2, as well as an output arrangement 3 at a second end, whereby the output arrangement 3 comprises an output scraper 4 with at least one scraper arm 5, as well as at least one cleaning member 6, a driving arrangement 7, a driving axle 8, a bearing 9, a supporting structure 10 for the driving arrangement 7, a normally open first outlet 11, as well as, preferably, a normally closed second outlet, whereby the first outlet 11 and the second outlet 12 are provided in the wall 1 of the pressure vessel.

Abstract: A method for adjusting the alkalinity of a pulp slurry in a broke pulper, and more particularly, to adjusting the pH of the pulp slurry using carbon dioxide.

Abstract: A wastepaper treatment method and system which combines the pulping and sorting in a pulping drum (10) with a following wet-strength processing, performed with high mechanical intensity, e.g., in a pulper (20). With the easily pulping paper materials being separated already from the drum (10) in a fines fraction (3), particular advantages result in terms of quality and economy.

Abstract: A method of oxygen delignification of medium consistency pulp slurry, which includes the steps of providing a pulp slurry of from approximately ten percent to sixteen percent consistency, at a temperature of from approximately 170-240.degree. F., preferably from 190 to 220.degree. F., thoroughly impregnating the slurry with oxygen gas, and with alkali to bring the slurry to a pH of at least 11, more preferably 12, introducing the slurry to oxygen gas in a high shear mixer, for agitating mixing therein, reacting the slurry in a first pressurized reactor for between 5 to 10 minutes, returning the pH of the slurry to at least 11, more preferably 12, with a residual alkali concentration of at least 1.25 gpl, thoroughly impregnating the slurry with H.sub.2 O.sub.2 and oxygen gas, and reacting the slurry in a second reactor for between 30 to 180 minutes.

Abstract: A guide vane is provided in a pin fluffer to assist in pulp mat retention during fluffing by providing a cyclic lift component to the mat as it passes over the vane thereby also further increasing retention time obtained in the fluffer.

Abstract: A method for reducing brightness reversion and yellowness (b*) of bleached mechanical wood pulps. The pulp is digested in an aqueous formaldehyde solution containing carbonate, preferably in an amount up to 30% by weight of pulp. Paper made from the digested pulp can be further improved by treating with a reversion inhibitor such as a polyethylene glycol bisthiol.

Abstract: A process and apparatus for treating and particularly bleaching pulp contacts a pulp with a gaseous reaction medium in a reactor tower. The pulp is fluffed and refined before being added to the pulp bed and then homogeneously permeated with the gaseous reaction medium to produce a uniformly treated pulp. A distribution device is included in the reactor to uniformly distribute the pulp in the reactor and form a homogenous pulp bed having a substantially even upper surface uniform bed depth.

Abstract: A process for bleaching chemical pulp for paper manufacturing comprising delignifying and bleaching chemical pulp which has been treated by cooking by simultaneous use of chlorine dioxide, a peroxide, and at least one reaction catalyst selected from the group consisting of oxoacids of elements of Groups IV, V and VI and salts of these acids. Formation of organic chlorine compounds as by-products is suppressed by decreasing the amount of chlorine dioxide used in the ECF bleaching process in the first stage, and thus environmental toxicity in the waste water discharged from the bleaching process is decreased. Chemical pulp having a high degree of brightness is economically produced because increase in the production capacity is not required at all or suppressed to the minimum, and the investment cost is reduced to the minimum when the bleaching with chlorine in the first stage is converted into the bleaching with chlorine dioxide which is an ECF bleaching process.

Abstract: A process for bleaching cellulosic pulp to a G.E. brightness of at least about 75 and a viscosity of at least about 14 wherein the effluent from the bleaching process is of reduced colored matter content and exhibits reduced COD. The process comprises DZD stages without interstage treatment of the pulp other than by an optional water wash.

Abstract: When closing the process of manufacturing cellulose pulp of high brightness, i.e. including the recovery of essentially all waste liquor, there is an untenable enrichment of certain basic elements, such as sodium and sulphur. The present invention provides a partial solution to this problem and is concerned with a method in bleaching with ozone lignocellulosic material, e.g. cellulose pulp, which has been at least partially manufactured chemically, in the presence of water at a degre of acidity, expressed as pH, of 2-5. The method is characterized in that the acidity is maintained during the ozone bleaching process by adding a sulphuric acid solution or an acid sodium sulphate solution produced by electrolysis or electrodialysis of an essentially neutral sodium sulphate solution obtained by recycling chemicals in a system to which waste liquor from the ozone bleaching process is added.

Abstract: The efficiency by which pulp cooking liquor components penetrate the wood and enable lignin and resins to be removed from the cellulosic materials is increased by contacting wood chips and the like with a liquid mixture comprised of white liquor containing at least one surfactant selected from the group consisting of a polymethylalkylsiloxane; a co- and terpolymer of silicone and a polyhydric alcohol; an alkoxylated aryl phosphate; an alkoxylated branched alkyl phosphate; an alkoxylated branched alcohol; an alkyl polyglycoside, an alkoxylated alkyl polyglycoside; a mixture of alkali metal salts of alkyl aromatic sulfate, a sulfosuccinate and a silicone; and combinations thereof; for a residence time effective to extract resinous components without substantial degradation of cellulose and thereafter heating at least a portion of the resulting mixture and wood chips.

Abstract: Provided is a process for removing metals from a bleaching plant spent liquor and recovering a chelating agent which includes the steps of: heating a spent liquor containing a chelate comprising metals bound in a chelating agent to a temperature of at least about 140.degree. C.

Abstract: A process of dignifying lignocellulosic pulp with oxygen followed by treatment of the delignified pulp with a chelating agent, followed by washing, followed by treatment with hydrogen peroxide at an alkaline pH in the presence of an alkali metal silicate at a temperature greater than 100.degree. C. and a pressure greater than 1.5 times the saturated vapor pressure.

Abstract: An automated tracer system and method for measuring the residence time of wood pulp as it moves through various stages of processing in a pulp mill. A tracer compound comprising a neutral salt of a halogen is introduced into a first location in the path of the pulp slurry; at a second location an automated detector detects the concentration of tracer compound over a time period; a controller relays a voltage signal from the detector to a processor which uses a calibration curve to integrate tracer concentration over time and thereby derive pulp residence, between the first and second locations.

Abstract: Kraft pulp is bleached to an acceptable brightness (e.g. 86 ISO or more) without using chlorinated organic compounds, yet the strength of the produced pulp remains commercially acceptable. In the manufacture of pulp, the pulp which is cooked and oxygen delignified to a kappa number of 14 or less, and then is bleached with ozone at a medium consistency. After the ozone treatment, heavy metals are removed from the pulp, and then the pulp is led to oxygen and/or peroxide treatment, which is followed by a second ozone bleaching stage. The sequence (ZT) (EOP) (ZP) is preferred.