Abstract: A process for chlorine-free bleaching of chemical pulp in association with the production thereof, where a suspension of the pulp preferably has a concentration exceeding 8% of cellulose-containing fiber material and where the pulp entering into a bleaching line is preferably fed continuously through at least one bleaching vessel in the bleaching line, is treated with at least one acid for adjusting the pH to a value below 7, and with a chelating agent, and is subsequently bleached in at least one stage to a brightness exceeding 75% ISO, preferably exceeding 80%, with hydrogen peroxide or the corresponding quantity of another peroxide, employed in a quantity exceeding 5 kg/BDMT, where the peroxide bleaching takes place at elevated temperature and at a pressure in the bleaching vessel which exceeds 2 bar and where the cross-sectional area of the bleaching vessel exceeds 3 m.sup.2 and the area of the metal surface exposed towards the interior of the bleaching vessel is less than 4V m.sup.

Abstract: An improved process for inhibiting calcium carbonate scaling in aqueous systems such as that employed in the kraft process for the production of wood pulp. Such an improved process is achieved by the addition to the system of at least one antiscalant comprising at least one monomer unit derived from the group consisting of 1,2-dihydroxy-3-butene, N-(hydroxymethyl) acrylamide, and N-(sulfomethyl) acrylamide, and at least one monomer unit derived from the group consisting of maleic acid, acrylic acid, acrylamide, methacrylic acid, itaconic acid, vinyl sulfonic acid, styrene sulfonic acid, N-tertbutylacrylamide, butoxymethylacrylamide, N,N-dimethylacrylamide, sodium acrylamidomethyl propane sulfonic acid, and salts thereof, with the proviso that said polymers do not contain the monomer unit --(CH.sub.2 --CH.dbd.CH--CH.sub.2 --O)--.

Abstract: An apparatus and method for use in a displacement batch digesting process is provided which reduces the amount of equipment required to carry out an efficient displacement batch digestion process. Specifically, an apparatus and method are disclosed which eliminates the need for separate warm fill pumps, hot fill pumps and further which consolidates the cool pad pump, displacement pump and dilution pump functions into a single booster pump. Still further, the recirculation pump and discharge pump functions are consolidated into a single pump.

Abstract: A process for conditioning an ozone gas recycle stream in an ozone pulp bleaching process, wherein the level of carbon dioxide in the recycle stream is controlled to allow full capacity operation of the ozone generator. Carbon dioxide concentration is identified over the relevant operational ranges and maximum concentration is identified for full capacity/optimum efficiency operation. Specific methods are described for controlling carbon dioxide concentration including purging a portion of the recycle stream, counter-current scrubbing of the recycle stream with an alkaline solution and passing the recycle stream through an adsorbent material. Contaminants entering the system also may be reduced by directing the purged recycle stream, which is relatively oxygen rich, into the dewatering press where pulp consistency is increased. In this manner nitrogen surrounding the pulp is displaced by oxygen and thus, does not enter the bleaching/ozone system with the pulp.

Abstract: Enhanced removal of lignin and other extractives in a pulping process is achieved by contacting wood chips and the like with a liquid mixture comprised of white liquor and aminoalkoxylsilane and optionally, one or more nonionic and/or anionic surfactants.

Abstract: A process for the delignification and bleaching of chemical pulp utilizes an acid treatment stage aimed at reducing the quantity of hexene uronic acids present in the pulp by at least 30%, and a pH adjustment stage of the pulp aimed at depositing or redepositing ions of alkaline-earth metals on the fibres of the pulp. The process further includes a washing stage of the pulp and a treatment stage of the pulp with an oxidizing agent. A chelating agent is added to the pulp before and/or during the acid treatment stage and/or before or during the pH adjustment stage or between the pH adjustment stage and washing stage.

Abstract: Filtrates from bleach plants for cellulosic (paper) pulp non-chlorine bleaching sequences are treated to minimize the consumption of ozone in ozone bleaching stages. Organic material in the filtrate used in a washer just prior to an ozone stage is oxidized to make the organic material less attractive to the ozone. It may be oxidized by indirectly heating the filtrate, and then reacting it with oxygen gas in a reactor. Alkali may be added to the filtrate in the reactor. Metallic ions are also removed from the system by applying an electrical potential either to the filtrate, an entire washer prior to the ozone stage, or to the pulp line prior to the ozone stage. All of the wash filtrates are treated and recirculated so as not to discharge any wash filtrates into the environment, or so that the only wash filtrate discharged from the washing system of the bleaching plant is a small stream used for smelt dissolution. A typical non-chlorine bleaching sequence utilized may be OAZEZP.

Abstract: A process for modifying, breaking down or bleaching lignin, material containing lignin or like substances uses oxidation catalysts and suitable oxidizing agents wherein these catalysts are used in combination with aliphatic, cycloaliphatic, hetercyclic or aromatic compounds containing NO, NOH or (A).

Abstract: A process for producing a thiourea dioxide fluid by mixing thiourea and a peroxide, or thiourea, a peroxide and a reaction catalyst, or thiourea, a peroxide, a reaction catalyst and a chelating agent, in the absence or presence of pulp and a process for bleaching pulp by the use of the thiourea dioxide fluid produced by the above process economically advantageously with a small chemicals loss and by small consumption of energy.

Abstract: A process for bleaching high-yield (mechanical or chemi-mechanical) pulps to high brightnesses and low yellownesses (b*) in a single treatment employs di-oxygen gas (O.sub.2), alkaline agent and a borohydride. The combined treatment gives brightnesses comparable with those achieved with stabilized alkaline hydrogen peroxide. By comparison the reaction of di-oxygen and alkali alone darkens high-yield pulps; and treatment with alkaline borohydride in the absence of added di-oxygen bleaches to give only about half the brightness gained if di-oxygen is added. The bleaching may possibly occur through the conversion of di-oxygen molecules (O.sub.2) to hydroperoxide ions (HOO-) utilizing ionized phenolic groups or hydroquinones in the lignin. The hydroperoxide ions are thus generated in situ in the lignin and can destroy colored lignin chromophores. Without the addition of borohydride the lignin phenolic groups would be irreversibly oxidized.

Abstract: Located within the annular screen of the pressure diffuser is a tubular baffle hung from adjacent the top of the vessel. The baffle has two headers disposed on its inner surface, with openings in the tube providing communication between the exterior of the tube and the headers. A conduit extends from each header to an arm at the top of the vessel, to allow extracted liquid to be discharged. Another extraction conduit is provided at the bottom of the vessel, in communication with the screen interior and the tubular baffle interior. Treatment liquid, such as wash liquid, may be introduced at two, three, or more positions along the vessel with the liquid extracted from the first and second headers being introduceable at different positions along the vessel. A flexible, elastomeric material, sealing element with integral annular skirt may extend from the bottom end of the tubular baffle and engage the screen to provide a seal minimizing mixing between stages.

Abstract: A flow management system and process for providing controlled separation and sizing of an incoming flow of wood chips. A flow management screen is provided in the form of a horizontal disk screen having a variable speed drive, with the drive controlled based upon the flow rate of wood chips to the screen. By controlling the rotational speed of the disks of the horizontal disk screen, the flow separation and sizing to subsequent screening stations can be predicted and controlled. As a result, more consistent output is provided, as well as improved system efficiency and ability to accommodate for varying operational conditions and wear.

Abstract: A number of different, efficient treatments of slurries and liquid with gas can be provided. A slurry or liquid is introduced into a first end of a vortex. A gas--such as a chemically reactive gas--is introduced from exteriorly of the vortex into contact with the slurry or liquid in the vortex, so that a desired reaction between the slurry or liquid and the gas takes place. The treated slurry or liquid is removed from the second end of the vortex while any residual or carrier gas is removed from the first end of the vortex. Gas introduction is preferably accomplished through a porous surface of revolution (e.g. cylindrical or conical) wall surrounding the vortex, the gas being in minute bubble form when it enters the slurry or liquid.

Abstract: An apparatus and method for bleaching high consistency lignocellulosic pulp using ozone supplied in an ozone containing gas. The bleaching reactor apparatus according to the invention is a generally cylindrical vessel with a rotatable shaft having radially extending paddles arranged in a configuration to minimize axial dispersion of the pulp and maximize radial dispersion of the pulp to provide a radially dispersed plug flow of pulp through the reactor in the presence of the ozone to provide substantially uniformly bleached pulp.

Abstract: In a pulp digester for continuous cooking under raised pressure and temperature of fiber material in a vertical digester (1), input of fiber material and cooking liquid takes place at the top of the digester, withdrawal of spent cooking liquor is carried out from at least one digester screening arrangement (1D) between the top and the bottom of the digester, and fiber material is fed out from the bottom (1C) of the digester, and at least one screening arrangement (2) in the lower half of the digester, wherein at least one of said screening arrangements (1, 2) has at least one screen element (2A) of which the main configuration is of angular shape, preferably rectangular, most preferred square, having a screen face (3A) of which the total area is less than 1 m.sup.

Abstract: A process for bleaching pulp, in which, after fiber liberation, a first filtrate containing metals, principally in ionic form, is separated off from the pulp, and supplied downstream to the pulp flow after a bleaching stage.

Abstract: A method for making shaped pasta products having a reduced moisture content. The drying requirements for these shaped pasta products are substantially reduced permitting a substantial savings in energy and time. Processing at reduced moisture levels is accomplished by operating at higher extrusion temperatures. The temperature is selected so as to avoid cooking the extruded alimentary pastes. Dried, uncooked pastas having a unique appearance are also provided.

Abstract: A method of making a wood pulp is disclosed. Wood is first chipped into wood chips. The wood chips are treated with an amount of sulfite salt sufficient to inhibit indigenous microorganism growth. The treated wood chips are introduced into a bioreactor and inoculated with a culture of white-rot fungus. The wood chips are incubated under conditions favoring the propagation of white-rot fungus and then mechanically pulped.

Abstract: An oxygen delignification method and apparatus in which a charge of heated wood pulp is reacted with oxygen in the presence of a charge of caustic soda in a plurality of reaction stages located between mixing stages in which caustic is mixed with the wood pulp. The use of the plurality of mixing stages reduces peak pH exposure of the wood pulp that would otherwise occur if the charges of caustic and wood pulp were mixed all at once. Moreover, the caustic mixed in such manner replenishes neutralized caustic and ensures that the average pH level is increased above that in conventional oxygen delignification. The increase in average pH level favors an increase in the delignification. Filtrate from a washing stage is introduced into the mixing stages to prevent wood pulp degradation.

Abstract: A method and apparatus for producing a glass ware, such as a bowl or plate, via vacuum forming. A deformable glass ribbon is passed through a pair of parallel rolls or rollers, one of the rollers having a recessed cavity thereon for forming a thicker product zone and a thinner cullet zone on the glass ribbon. The product zone may be specifically configured to compensate for process stretching of the glass ribbon during the vacuum forming process. The product zone is registered over a vacuum mold, and a vacuum is applied to the mold to thereby deform the glass to a concave shape and thus form the dish. The dish is separated from the glass ribbon by trimming at the periphery of the dish.