摘要:
The present invention concerns a process for reducing the susceptibility of lignocellulosic material to unwanted yellowing, particularly yellowing caused by light and heat. According to the invention, the fibres are activated enzymatically or chemically and then contacted with a modifying agent capable of bonding to the oxidized fibre material, rendering the lignocellulosic fibre material improved resistance to brightness reversion. By means of the invention, brightness reversion caused by light or heat or a combination thereof can be retarded and even stopped.
摘要:
The present invention relates to a process for deinking waste paper comprising treating the waste paper with a peroxide compound in an aqueous alkaline medium in the presence of a first polymer (A) comprising a Ca-binding polymer in the form of a polycarboxylate polymer and a second polymer (B) comprising a poly-alfa-hydroxyacrylic acid or a salt thereof or the corresponding polylactone, said process additionally comprising treating the waste paper with at least one non-ionic surfactant or with at least one combination of a non-ionic surfactant and a fatty acid or a salt thereof to promote ink detachment and/or ink removal.
摘要:
A method for the preparation of pulp by means of alkaline cooking, in which method spent liquor is transferred to pressurized tanks, and at least one liquor is expanded corresponding to a temperature difference of 1 to 5° C. The generated steam is led to turpentine recovery. Thus, the removal of turpentine and gases dissolved in said liquor is effective, the amount of recovered turpentine increases, and pulp of better washability and higher quality is obtained.
摘要:
A process for the production of pulp using alkaline delignification is disclosed, wherein cellulosic material is initially treated with steam, and a chelating agent is added in connection with the steam treatment. The end pH of the steam treatment stage is below 5. Liquors containing chelated, so-called non-process compounds are not recycled in the pulping process, but expelled therefrom for further processing where non-process compounds are eliminated.
摘要:
The present invention relates to a process for deinking waste paper comprising treating the waste paper with a peroxide compound in an aqueous alkaline medium in the presence of a first polymer (A) comprising a Ca-binding polymer in the form of a polycarboxylate polymer and a second polymer (B) comprising a poly-alfa-hydroxyacrylic acid or a salt thereof or the corresponding polylactone, said process additionally comprising treating the waste paper with at least one non-ionic surfactant or with at least one combination of a non-ionic surfactant and a fatty acid or a salt thereof to promote ink detachment and/or ink removal.
摘要:
Methods for producing chemical pulp from lignocellulose-containing material in processes for kraft pulp production are disclosed including charging the lignocellulose-containing material to a digester, initially treating the lignocellulose-containing material with an impregnation liquor, and then treating the impregnated lignocellulose-containing material with hot liquor and displacing calcium-containing spent liquor from the digester during that treatment, heating and cooking the heated lignocellulose-containing material to produce cooked lignocellulose-containing material and cooking liquor and displacing the cooking liquor from the digester using at least a portion of the displaced calcium-containing spent liquor.
摘要:
The present invention relates to a process for producing microcellulose comprising subjecting fibrous cellulosic material to acid hydrolysis at a temperature of at least 40° C. and at a consistency of at least 8% on dry weight of the cellulose, wherein the amount of added acid is from 0.2 to 2%, preferably from 0.5 to 1.5% on dry weight of the cellulose.
摘要:
Containers for collecting and discharging particulate lignocellulosic material are disclosed, including a cylindrical upper portion, a lower portion tapering towards a bottom elongated space, an exit pipe below the bottom, a pair of parallel screws mounted on parallel shafts in the elongated space in a common horizontal plane for feeding the particulate lignocellulosic material towards the exit pipe, a pair of distributors disposed on the parallel screws above the exit pipe comprising radial discs, and a pump below the exit pipe for transporting the particulate lignocellulosic material to a subsequent step.
摘要:
The present invention concerns a method and an apparatus for removing gas from comminuted lignocellulose material, wherein material is heated with steam to a degasification temperature and the heated material flow is led as a dense composed bed through a gas removal stage. The material is heated by introducing a steam flow into the material flow in transversal direction with respect to the direction of the material flow.
摘要:
According to the invention, polysulfide is used in the manufacture of kraft pulp in the initial stage of a displacement batch process in order to improve the yield. Polysulfide-containing white liquor is added inter-mixed with the first liquor charged to the digester, or as a separate charge before the impregnation liquor is introduced. Preferably, a cooking catalyst, e.g. antraquinone, is added to the white liquor charge as the cooking stage commences.