Abstract: There is provided a method of producing a high temperature chemithermomechanical pulp (HT-CTMP), said method comprising the steps of: —impregnating maple wood chips with an impregnation liquid comprising sulfite and NaOH to obtain impregnated chips; —heating the impregnated chips from the impregnation step by applying steam having a temperature of at least 150° C., such as at least 160° C. to obtain pre-treated chips; and—defibration of the pre-treated chips from the heating step to obtain a pulp, wherein the amount of NaOH supplied to the impregnation step is less than 10.0 kg per dry tonne of chips, such as less than 5 kg per dry tonne of chips. A HT-CTMP formed from maple wood is also provided.

Abstract: There is provided a method of preparing chemithermomechanical CTMP from maple wood, said method comprising the steps of: a) providing maple wood chips having an average length below 20 mm, such as below 19 mm; b) washing the maple wood chips with water; c) steaming the washed maple wood chips for a period of at least 15 minutes to obtain pre-steamed chips; d) impregnating the pre-steamed chips to obtain impregnated chips; e) heating the impregnated chips to obtain pre-treated chips; and f) defibration of the pre-treated chips.

Abstract: There is provided a high temperature chemithermomechanical pulp (HT-CTMP) formed from a mixture of maple wood and softwood, wherein the dry weight ratio of maple wood to softwood in said mixture is between 92:8 and 50:50. A method of producing HT-CTMP is also provided.

Abstract: There is provided a method of preparing chemithermomechanical pulp (CTMP), said method comprising the steps of: pre-impregnating wood chips with a pre-impregnation liquid to obtain pre-impregnated wood chips; feeding the pre-impregnated wood chips to an impregnation zone comprising an impregnation liquid comprising sulfite and/or alkali using a plug screw such that the pre-impregnated wood chips expand in the impregnation zone and absorbs the impregnation liquid, thereby providing impregnated wood chips; transferring the impregnated wood chips to a heating zone without compressing the impregnated wood chips; heating the impregnated wood chips in the heating zone with steam having a temperature of above 140° C., such as at least 150° C., such as at least 160° C., to obtain pre-treated wood chips; and defibration of the pre-treated wood chips, wherein the residence time in the heating zone is no more than two minutes.

Abstract: There is provided a method of forming a high temperature chemithermomechanical pulp (HT-CTMP) comprising the steps of: a) mixing hardwood chips and softwood chips to obtain a mixture, wherein the dry weight ratio of hardwood to softwood in said mixture is between 85:15 and 65:35; b) impregnating the chips of the mixture with an impregnation liquid comprising sulfite and optionally NaOH to obtain impregnated chips; c) applying steam having a temperature of at least 150° C. to the impregnated chips to obtain pretreated chips; and d) defibrating the pretreated chips, wherein the mass flow of sulfite (calculated as Na2SO3) to step b) is higher than the mass flow of NaOH to step b) and the residence time in step c) is no more than two minutes.

Abstract: The present disclosure provides a high temperature chemithermomechanical pulp (HT-CTMP) formed from a mixture of hardwood and spruce wood, wherein the dry weight ratio of hardwood to spruce wood in said mixture is between 65:35 and 20:80. A method of producing HT-CTMP is also provided.

Abstract: A method of producing a paper or paperboard product having at least one ply comprising high yield pulp (HYP), comprising the steps of: —providing a furnish comprising at least 50% of high yield pulp (HYP) of a total pulp content in said furnish, said high yield pulp being produced with a wood yield above 85%; —dewatering the furnish to form a moist web and pressing said moist web to a dry solids content of at least 40-70%; and —densifying the moist web to a density above 600 kg/m3 in a press nip of a paper machine at a temperature above a softening temperature of water-saturated lignin comprised in said high yield pulp to provide a paper or paperboard product, containing at least 30% high yield pulp (HYP) of a total pulp content of said product.

Abstract: A method of producing a paper or paperboard product having at least one ply comprising high yield pulp (HYP), comprising the steps of: —providing a furnish comprising at least 50% of high yield pulp (HYP) of a total pulp content in said furnish, said high yield pulp being produced with a wood yield above 85%; —dewatering the furnish to form a moist web and pressing said moist web to a dry solids content of at least 40-70%; and —densifying the moist web to a density above 600 kg/m3 in a press nip of a paper machine at a temperature above a softening temperature of water-saturated lignin comprised in said high yield pulp to provide a paper or paperboard product, containing at least 30% high yield pulp (HYP) of a total pulp content of said product.

Abstract: This patent application describes a method to produce wood chips with the intention of reducing the energy consumption in the subsequent process steps for pulp production. With the present method wood chipping is done in a wood chipper where the chipping tool (3) has an angle ? (4) within the interval of 75° to 105° between the fibre direction of the log and the side of the tool which faces the chip (2). Angles in this interval will cause an axially directed compression of the chip which will cause a cracking of the wood during chipping.

Abstract: The content of ray cells in cellulose pulp causes problems and therefore these ray cells should be removed from the cellulose pulp to improve the pulp quality. The present invention makes this possible and comprises a method wherein at first an advancing pulp suspension is screened or vortex cleaned, (3) leading to the formation of an accept pulp fraction (4) and a reject pulp fraction (5) and that the reject pulp fraction is cleaned and divided, and that accepted material (pulp fibres and valuable fine material) is brought to further treatment and/or use.

Abstract: There is a need for a cheaper method of producing bleached TMP and CTMP without impairing the properties of the pulp.