This disclosure relates to methods of making novel dissolving wood pulps by processes comprising acid prehydrolysis, pulping, and a multi-stage bleaching process comprising oxidation with a catalyst and peroxide under acidic conditions, as well as to products made therefrom having a combination of medium-purity, low viscosity, and improved reactivity, filterability, and/or clogging that can be used as a substitute for traditional high-purity dissolving pulps in a wide variety of applications.

Methods of and systems for controlling dosing of drainage aid and optionally defoamer to brown stock of a brown stock washing process are provided. Certain embodiments of the invention provide independent control of drainage aid and/or defoamer to brown stock, which tends to provide improved efficiency in dosing each of the drainage aid and the defoamer.

Methods of and systems for controlling dosing of drainage aid and optionally defoamer to brown stock of a brown stock washing process are provided. Certain embodiments of the invention provide independent control of drainage aid and/or defoamer to brown stock, which tends to provide improved efficiency in dosing each of the drainage aid and the defoamer.

Method and apparatus for removing liquid from a gas/liquid flow for use in pulp washers, deinking cells, and the like are disclosed. A gas/liquid separator includes a separation chamber with a flow director providing a gas/liquid flow from a receptacle into the separator in a direction causing impingement of entrained liquid particles on a chamber wall such that liquid particles coalesce into liquid droplets that travel downward by the force of gravity to a separated liquid drain and drained outside the receptacle. A tangential flow inlet provides greater impingement than a cyclonic flow introduced at the lower end of the gas/liquid separator in initially directed upwards. Separated liquid could further be taken outside the pulp washer system for further processing or disposal based on the chemical content of the separated liquid.

A method for manufacturing dissolving pulp using wood material is disclosed. The method comprises subjecting the wood material to a hydrothermal treatment using steam and/or water, digesting the wood material obtained to a pulp in a kraft cooking process; subjecting the pulp to a cold caustic extraction CCE; and dewatering, washing and pressing the pulp to get a pulp product having a carbohydrate content. The wood material can be a coniferous wood material, and whereby the mild hydrothermal treatment is performed to reach a P-factor of from 100-300, and whereby the cold caustic extraction is executed to reach a combined concentration of anhydromannose and anhydroxylose of 5 weight %, or less, of the carbohydrate content of the pulp product.

A method for manufacturing dissolving pulp using wood material is disclosed. The method comprises subjecting the wood material to a hydrothermal treatment using steam and/or water, digesting the wood material obtained to a pulp in a kraft cooking process; subjecting the pulp to a cold caustic extraction CCE; and dewatering, washing and pressing the pulp to get a pulp product having a carbohydrate content. The wood material can be a coniferous wood material, and whereby the mild hydrothermal treatment is performed to reach a P-factor of from 100-300, and whereby the cold caustic extraction is executed to reach a combined concentration of anhydromannose and anhydroxylose of 5 weight %, or less, of the carbohydrate content of the pulp product.

A vapor relief strainer cleaning assembly comprises a turbine and dislodger assembly, wherein the turbine is configured to move a dislodger assembly disposed within a vapor screen relief vessel. Exemplary dislodger assemblies are configured to be powered by vapor or gas and to use excess vapor or gas optionally to dislodge non-condensable contaminants from the filter screen or to facilitate contaminant dislodgement from the inner wall of the filter screen.

A vapor relief strainer cleaning assembly comprises a turbine and dislodger assembly, wherein the turbine is configured to move a dislodger assembly disposed within a vapor screen relief vessel. Exemplary dislodger assemblies are configured to be powered by vapor or gas and to use excess vapor or gas optionally to dislodge non-condensable contaminants from the filter screen or to facilitate contaminant dislodgement from the inner wall of the filter screen.

A method for degumming bast fibers comprising soaking a source of bast fiber in a saline solution. The source of bast fiber may be soaked in a saline solution having a concentration ranging between less than 1 part per thousand to about 200 parts per thousand. The saline concentration may vary as the source of bast fiber is soaking, or by alternating bast fiber between aqueous solutions of differing ionic concentrations. In one embodiment, the source of bast fiber is soaked in seawater, wherein the saline concentration varies by alternating the salinity using a tide. The source of bast fiber may be hemp.

A method for degumming bast fibers comprising soaking a source of bast fiber in a saline solution. The source of bast fiber may be soaked in a saline solution having a concentration ranging between less than 1 part per thousand to about 200 parts per thousand. The saline concentration may vary as the source of bast fiber is soaking, or by alternating bast fiber between aqueous solutions of differing ionic concentrations. In one embodiment, the source of bast fiber is soaked in seawater, wherein the saline concentration varies by alternating the salinity using a tide. The source of bast fiber may be hemp.