VALMET AB

Embodiments herein relate to a system ( 200; 300; 400; 500 ) for obtaining methanol from foul condensate ( 101 ) of a pulping process. The system ( 200; 300; 400; 500 ) comprises a primary stripper ( 102 ) arranged to strip the foul condensate ( 101 ) from pollutants, whereby a first methanol-containing condensate is obtained from the polluted stripper off gases (SOGs). The system ( 200; 300; 400; 500 ) also comprises a first acidification unit ( 202 ) arranged to acidify the first methanol-containing condensate. Further, the system ( 200; 300; 400; 500 ) comprises a secondary stripper ( 204 ) arranged to strip the acidified first methanol-containing condensate from pollutants to obtain a second methanol-containing condensate, and a distillation column ( 107 ) arranged to distil the second methanol-containing condensate from the secondary stripper ( 204 ) so as to obtain methanol. Embodiments herein also relate to a method performed in a system ( 200; 300; 400; 500 ) for obtaining methanol from foul condensate ( 101 ) of a pulping process.

A method for obtaining a strong hydrolysate from cellulosic material after a hydrolysis in a batch digester is disclosed. According to the invention the cellulosic material is exposed to a 2 stage hydrolysis with a first steam phase hydrolysis followed by a liquid phase hydrolysis, and wherein the steam phase is conducted such that the degree of packing of the cellulosic material results in at least a 20% up to 100% packing increase. The liquid phase hydrolysis includes adding hot and preferably acidified hydrolysis liquid and not establishing a total L/W ratio above 3.5, but sufficient to keep the cellulosic material under the level of the hydrolysis liquid.

The invention relates to a heat transfer tube ( 9 ) for falling film evaporation having a heating medium surface ( 21 ) to be heated by a heating medium, a falling film surface ( 20 ) to have spent liquor passing over it, and being made from an sheet metal material. The falling film surface of the heat transfer tube is equipped with a multitude of wire bumps (WB), each wire bump being spaced apart along the longitudinal axis (CC) of the heat transfer tube from a neighbouring wire bump by 3-300 mm, said wire bumps (WB) having a height (h) in the range 0.3 to 5.0 mm, a width (w) in the range 0.3-5.0 mm, and an inclination angle (a) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees. The invention also relates to a method for manufacturing said heat transfer tube.

A refiner segment for a refiner comprising refining zones provided with a pattern of bars arranged at a respective pumping feeding angle within a respective refining zone, and intermediate grooves between the bars, and dams extending between the bars and protruding above the surface of the grooves. The dams are arranged at least at the ends of at least some of the bars at the borders between the refining zones. Openings are formed at the borders between the refining zones, radially outside of the dams, where the openings are arranged such that a respective angle is formed between an imaginary line connecting the openings and a line which is perpendicular to a radius of the refiner segment, where the angle is directed towards the inner edge of the refiner segment, thereby allowing steam to pass through the openings and flow towards an inner edge of the refiner segment.

The invention relates to a heat transfer tube ( 9 ) for falling film evaporation having a heating medium surface ( 21 ) to be heated by a heating medium, a falling film surface ( 20 ) to have spent liquor passing over it, and being made from an iron based high alloy stainless steel material with an alloy content above 16.00% for Chromium and above 1% for Nickel. The falling film surface of the heat transfer tube is equipped with at least one weld ridge (WR; WR 1 , WR 2 ), said weld ridge having a height (h; h 2 ) in the range 0.3 to 5.0 mm, a width (w; w 2 ) in the range 0.5-15 mm, and an inclination angle (α; α 1 , α 2 ) versus a plane orthogonal to a longitudinal axis (CC) of the heat transfer tube in a range of 0-70 degrees so that each weld ridge is inclined and extends helically along at least a portion of the heat transfer tube or extend within a plane orthogonal to the longitudinal axis of the heat transfer tube and forms well ridge portions on the falling film surface such that the distance along the longitudinal axis of the heat transfer tube between adjacent weld ridge portions is within the range of 0 to 250 mm. The invention also relates to a method for manufacturing said heat transfer tube.

Disclosed is a refiner segment ( 1 ) that is adapted to be attached to a refining disc ( 30 ) of a refiner ( 100 ) of lignocellulosic material. The refiner segment ( 1 ) comprises a number N, N≥2, of bars ( 10 ) and a number, M≥2, of dams ( 11 ), said bars ( 10 ) and dams ( 11, 11 *) being arranged in a pattern whereby essentially box shaped regions ( 20 ) are created in areas defined by neighboring bars ( 10, 10 *) and at least two dams ( 11, 11 *) extending between said neighboring bars ( 10, 10 *) at different locations along the length direction of the bars ( 10, 10 *), wherein at least one of the bars ( 10, 0 *) that defines such an essentially box shaped region ( 20 ) comprises a bar weakening section ( 12 ), arranged within said essentially box shaped region ( 20 ), and provided to enable steam trapped in said essentially box shaped region ( 20 ) to escape said essentially box shaped region ( 20 ) via said bar weakening section ( 12 ). Disclosed is also a refiner disc provided with such a refiner segment and a refiner comprising such a refiner segment.

The invention relates to a system ( 1 ) comprising a feeding device ( 2 ) comprising a channel ( 6 ) having an inlet ( 8 ) and an outlet ( 10 ) and a feed screw ( 12 ) for conveying biomass material through the channel. The feed screw comprises a screw flight ( 12 b ) that extends from a first end ( 12 c ) to a second end ( 12 d ) and is adapted to form a gas impermeable plug of biomass. The system comprises at least one primary measuring unit ( 14; 16 ) adapted to continuously measure a primary variable indicative of the gas permeability of the plug, which primary measuring unit is connected to said feeding device between the first end of the screw flight and the outlet; and a control unit ( 3 ) adapted to use said primary variable values to monitor the gas permeability of the plug. The invention also relates to a method for preventing blow back in the above described system.

There is disclosed a refiner segment ( 10 ) for a refiner ( 1 ) of lignocellulosic material. The refiner segment ( 10 ) is part of a refiner disc ( 100 ) that comprises a center area ( 11 ). The refiner segment ( 10 ) comprises a number H, N≥2, of bar zones (Z i ,i=1, 2, . . . N) that are arranged at different radial positions with regard to a radial direction R extending from the center area ( 11 ) of the refiner disc ( 100 )_towards the periphery of the refiner segment ( 10 ). Each of the bar zones (Z i ) are defined by a corresponding set of refining bars (Z i RBi , i=1, 2, . . . M) that are distributed angularly and encircles the center area ( 11 ). The refining bars (Z i RBi ) belonging to different but neighboring bar zones (Z i , Z i+1 ) are angularly offset and refining bars (Z i RBi ) belonging to different but neighboring bar zones are arranged in such a way that a tangential direction of a particular refining bar (Z k RBk ) belonging to a bar zone (Z i ,) points in a direction towards the mid-point between two refining bars (Z k+1 RBk+1 ) belonging to a neighboring bar zone (Z i , Z i+1 ) and wherein the length of refining bars belonging to different bar zones decreases from a largest length for refining bars (Z i RBi ) belonging to the innermost bar zone (Z 1 ), with regard to the center ( 11 ) of said refining disc ( 100 ), to the smallest length for refining bars (Z N RBN ) belonging to the outermost bar zone (Z N ) adjacent the periphery of said refiner segment ( 10 ). There is also disclosed a rotor disc comprising such a refining segment, a stator disc adapted to cooperate with such a rotor disc as well as a refiner comprising at least one of such a rotor disc and stator disc.