A system and process of producing pulp from lignocellulosic material after the lignocellulosic material has undergone compression (pressurization), maceration and removal of extractives produced during compression and maceration followed by chemical addition, fiberization, digestion (cooking) and further mechanical refining.

A system and process of producing pulp from lignocellulosic material after the lignocellulosic material has undergone compression (pressurization), maceration and removal of extractives produced during compression and maceration followed by chemical addition, fiberization, digestion (cooking) and further mechanical refining.

The invention relates to a chip chute (4; 21; 31; 41) which comprises an elongated, open main body (22; 32; 42) having a rectangular transverse cross-section, and comprises further a transition portion (23; 33; 43), which connects to the elongated, open main body (22; 32; 42) and comprises a circular outlet (26; 36; 46). The invention relates further to a feeding system (1) for transporting comminuted lignocellulosic material from a vessel (2) to a pump (3) located below the vessel (2), wherein such a chip chute (4; 21; 31; 41) is arranged between the vessel (2) and the pum (3).

The invention relates to a chip chute (4; 21; 31; 41) which comprises an elongated, open main body (22; 32; 42) having a rectangular transverse cross-section, and comprises further a transition portion (23; 33; 43), which connects to the elongated, open main body (22; 32; 42) and comprises a circular outlet (26; 36; 46). The invention relates further to a feeding system (1) for transporting comminuted lignocellulosic material from a vessel (2) to a pump (3) located below the vessel (2), wherein such a chip chute (4; 21; 31; 41) is arranged between the vessel (2) and the pum (3).

A feeding arrangement comprising a transportation means (3) for transportation of material from a material supply to at least a first chute (7) and a second chute (8), a plug screw feeder (11) for feeding the material to the treatment stage. The plug screw feeder (11) is provided with a first inlet opening (12) connected to the first chute (7), which first chute (7) is provided between the transportation means (3) and the plug screw feeder (11). Further, the transportation means (3) comprises at least selectively openable first and second outlets (4, 5) arranged at different axial positions along the transportation means (2), which first outlet (4) is in connection with the first chute (7) and the second outlet (5) is in connection with the second chute (8).

A feeding arrangement comprising a transportation means (3) for transportation of material from a material supply to at least a first chute (7) and a second chute (8), a plug screw feeder (11) for feeding the material to the treatment stage. The plug screw feeder (11) is provided with a first inlet opening (12) connected to the first chute (7), which first chute (7) is provided between the transportation means (3) and the plug screw feeder (11). Further, the transportation means (3) comprises at least selectively openable first and second outlets (4, 5) arranged at different axial positions along the transportation means (2), which first outlet (4) is in connection with the first chute (7) and the second outlet (5) is in connection with the second chute (8).

Methods and devices are provided for hydrothermal pretreatment of lignocellulosic biomass. A mechanically simple and inexpensive vertical steam reactor is fed with biomass feedstock from the top, while pretreated material is removed from the bottom in steady-state by operation of moveable upper and lower restrictor means, which project across the reactor cross section when engaged. The vertical column of biomass is supported by the upper restrictor means. This is periodically withdrawn from the reactor cross section, permitting the column of biomass to fall by force of gravity onto the lower restrictor means. The upper restrictor means is then re-inserted, after which the lower restrictor means is withdrawn permitting a plug of pretreated material to be removed by force of gravity. Using biomass feedstock that has been compressed in a reciprocating piston press to bulk density of at least 500 kg/m3, which can be fed dry into the reactor using simple, inexpensive sluice systems and then wetted inside the reactor, this system provides comparable biomass throughput at a fraction of the cost of traditional commercial hydrothermal pretreatment systems used in second generation biorefining.

Methods and devices are provided for hydrothermal pretreatment of lignocellulosic biomass. A mechanically simple and inexpensive vertical steam reactor is fed with biomass feedstock from the top, while pretreated material is removed from the bottom in steady-state by operation of moveable upper and lower restrictor means, which project across the reactor cross section when engaged. The vertical column of biomass is supported by the upper restrictor means. This is periodically withdrawn from the reactor cross section, permitting the column of biomass to fall by force of gravity onto the lower restrictor means. The upper restrictor means is then re-inserted, after which the lower restrictor means is withdrawn permitting a plug of pretreated material to be removed by force of gravity. Using biomass feedstock that has been compressed in a reciprocating piston press to bulk density of at least 500 kg/m3, which can be fed dry into the reactor using simple, inexpensive sluice systems and then wetted inside the reactor, this system provides comparable biomass throughput at a fraction of the cost of traditional commercial hydrothermal pretreatment systems used in second generation biorefining.

A screw feeder includes a pipe, feed screw, rotatory shaft, dewatering holes, anti-rotation bars extending inside the pipe and protruding towards the feed screw, an inlet to receive solid-liquid mixture, and an outlet to discharge partially dewatered solid. The pipe includes at least one pipe section having a first peripheral zone in a vertically lower area with dewatering holes but no anti-rotation bars and a second peripheral zone in a vertically upper area with anti-rotation bars. A pipe profile includes two differently shaped profiles, a first and second pipe profile are selected from a square-shaped, partly circular, and a partly elliptically-shaped profile. The first pipe profile is selected to enable outer edges of the feed screw to remove material overlying the dewatering holes, and the second pipe profile is selected to prohibit contact between the outer edges of the feed screw and the anti-rotation bars.

A screw feeder includes a pipe, feed screw, rotatory shaft, dewatering holes, anti-rotation bars extending inside the pipe and protruding towards the feed screw, an inlet to receive solid-liquid mixture, and an outlet to discharge partially dewatered solid. The pipe includes at least one pipe section having a first peripheral zone in a vertically lower area with dewatering holes but no anti-rotation bars and a second peripheral zone in a vertically upper area with anti-rotation bars. A pipe profile includes two differently shaped profiles, a first and second pipe profile are selected from a square-shaped, partly circular, and a partly elliptically-shaped profile. The first pipe profile is selected to enable outer edges of the feed screw to remove material overlying the dewatering holes, and the second pipe profile is selected to prohibit contact between the outer edges of the feed screw and the anti-rotation bars.