Described herein is a method for processing straw into an intermediate straw product. The method comprises: (a) treating straw with an alkaline solution having a p H of between about 10 and about 14, at a temperature of between about 20° C. and about 80° C., for a period of between about 6 hours and about 30 hours; (b) separating excess alkaline solution and the treated straw from each other; and (c) maintaining the treated straw in an anaerobic environment at a temperature of between about 30° C. and about 45° C., for a period of between about 6 hours and about 30 hours to produce an intermediate straw product. Also described is an intermediate product produced by the method; a method for extracting lignin from straw; lignin thereby produced; a method for extracting cellulose fibres from straw to produce paper pulp; cellulose fibres and paper pulp thereby produced; a method for producing a paper pulp product or a paper product; a product thereby produced; and a container and apparatus for processing straw according to the methods described.

Described herein is a method for processing straw into an intermediate straw product. The method comprises: (a) treating straw with an alkaline solution having a p H of between about 10 and about 14, at a temperature of between about 20° C. and about 80° C., for a period of between about 6 hours and about 30 hours; (b) separating excess alkaline solution and the treated straw from each other; and (c) maintaining the treated straw in an anaerobic environment at a temperature of between about 30° C. and about 45° C., for a period of between about 6 hours and about 30 hours to produce an intermediate straw product. Also described is an intermediate product produced by the method; a method for extracting lignin from straw; lignin thereby produced; a method for extracting cellulose fibres from straw to produce paper pulp; cellulose fibres and paper pulp thereby produced; a method for producing a paper pulp product or a paper product; a product thereby produced; and a container and apparatus for processing straw according to the methods described.

The invention is related to a method for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to obtain a cost efficient system both in aspects of investment costs but also in aspects of heat economy of operating the process is most of the total charge of alkali charged as heated polysulfide liquor to an first atmospheric vessel, wherein the hot polysulfide liquor flashes off steam providing most if not all of the necessary steaming effect for the cellulose material. The polysulfide liquor is then allowed to impregnate the cellulose material at a temperature closer to cooking temperature but still so low that essentially no delignification occurs in impregnation vessel, as the H-factor in impregnation vessel is kept within 1-20.

A plug screw feeder (1) comprises a plug screw (10) with a thread (12) and a plug screw housing (20) surrounding the plug screw. The plug screw housing comprises an inlet opening (24) in a side of the plug screw and in a vicinity of a first axial end (18) of the plug screw. The plug screw is arranged for feeding lignocellulosic biomass material (99) from the inlet opening to a second axial end (19) of the plug screw when being rotated. The thread, in at least a part of an inlet section (15) of the plug screw, presents a jagged peripheral rim (14A) with an inwards directed leading edge. The inlet section is defined as the section of the plug screw passing the inlet opening during rotation. A feeding arrangement and system for treatment of lignocellulosic biomass material comprising such a plug screw feeder is also disclosed.

A plug screw feeder (1) comprises a plug screw (10) with a thread (12) and a plug screw housing (20) surrounding the plug screw. The plug screw housing comprises an inlet opening (24) in a side of the plug screw and in a vicinity of a first axial end (18) of the plug screw. The plug screw is arranged for feeding lignocellulosic biomass material (99) from the inlet opening to a second axial end (19) of the plug screw when being rotated. The thread, in at least a part of an inlet section (15) of the plug screw, presents a jagged peripheral rim (14A) with an inwards directed leading edge. The inlet section is defined as the section of the plug screw passing the inlet opening during rotation. A feeding arrangement and system for treatment of lignocellulosic biomass material comprising such a plug screw feeder is also disclosed.

The bin arrangement is for collecting and discharging smaller ligno-cellulosic material. The bin has a transition part from a circular section of the bin and downwardly to a rectangular section with a long and short side of the rectangular section. The transition part could be built with few wall segments, thus needing less welding. Two rotary pocket feeders, each with at least one shaft extending parallel to the long side, are arranged directly under the rectangular section, enabling a uniform feed from the bin. The use of two rotary pocket feeders with this design directly under the bin does not destroy the even feed of material through the bin part, which otherwise is experienced from using conventional feed screws that feed material in a transverse direction from the bin outlet. The bin does not need to have a complex bin design which converges to a small circular inlet to a conventional rotary pocket feeder.

A method and system for heating a hydraulic digester, such as a single-vessel hydraulic digester, which has a top separator, a level of chips and a liquid phase above the level of chips. The method includes: a. entraining chips in liquor to produce a slurry having a first temperature, b. feeding the slurry of chips to the digester through the top separator, c. supplying direct steam to the liquid phase between the level of chips and the top separator to heat the slurry to a second temperature for the impregnation stage, wherein the steam is fed by using at least one steam injector having a plurality of steam discharge openings; and d. heating the slurry to a third temperature and cooking the chips in a cooking zone, and withdrawing the cooked pulp from the bottom of the digester.

A method and system for heating a hydraulic digester, such as a single-vessel hydraulic digester, which has a top separator, a level of chips and a liquid phase above the level of chips. The method includes: a. entraining chips in liquor to produce a slurry having a first temperature, b. feeding the slurry of chips to the digester through the top separator, c. supplying direct steam to the liquid phase between the level of chips and the top separator to heat the slurry to a second temperature for the impregnation stage, wherein the steam is fed by using at least one steam injector having a plurality of steam discharge openings; and d. heating the slurry to a third temperature and cooking the chips in a cooking zone, and withdrawing the cooked pulp from the bottom of the digester.

The present invention relates to an outlet system for transporting comminuted lignocellulosic material from a vessel, said bottom portion (1) having an upper circumference (15) that is essentially circular and a lower circumference (16) comprising at least two essentially straight portions (16a, 16c) opposite each other. The invention also relates to a vessel having such an outlet system.

The present invention relates to an outlet system for transporting comminuted lignocellulosic material from a vessel, said bottom portion (1) having an upper circumference (15) that is essentially circular and a lower circumference (16) comprising at least two essentially straight portions (16a, 16c) opposite each other. The invention also relates to a vessel having such an outlet system.