The disclosure relates to a method for preparing unbleached biomechanical pulp by hot steam and biological enzyme treatment and full utilization of by-products thereof, and belongs to the technical field of papermaking technology and comprehensive utilization of waste. The present disclosure proposes a method for preparing high-strength unbleached biomechanical pulp, using whole wheat straw as a raw material, by using hot water in coordination with an alkaline biological enzyme to treat whole wheat straw, thereby meeting the requirements for the production of unbleached linerboard and paper-based materials, and recycling by-products thereof to prepare biomass compound fertilizers, which creates wealth from solid waste and realizes the high-value full utilization of wheat straw. The preparation method of the disclosure is simple, green, clean and efficient, and has good practical application value and broad application prospects.

The invention relates to a method for treating biomass (2). In a step (S10), biomass (2) and an impregnation liquid are fed into a first reactor unit (10) such that the biomass (2) is impregnated with the impregnation liquid while the biomass (2) is transferred through the first reactor unit (10) by a conveyor means (11). In another step (S20), the impregnated biomass (2a) is transferred from the first reactor unit (10) to a separation unit (25), wherein at least a part of the impregnation liquid is separated from the impregnated biomass (2a) within the separation unit. In a step (S30), the separated impregnation liquid is discharged from the separation unit (25), such that a first part (26a) of the impregnation liquid is recirculated back to the first reactor unit (10). The invention further relates to a system for treating biomass (2).

Methods and systems for reducing the loss of usable fibers from whitewater while simultaneously increasing paper making machine performance and paper quality are provided. The methods and systems utilize a fractionating saveall to separate whitewater into a dilute wastewater fraction that contains unwanted fine particles and a thicker consistency reusable fraction containing paper-forming fibers. The reusable fraction is recirculated back into the whitewater stream, while the wastewater is routed away from the whitewater stream.

Processes and systems for treating Kraft pulping foul condensate are provided. The processes comprise removing volatile compounds from the foul condensate to produce a resulting condensate and removing methanol from the resulting condensate. The systems comprise a volatile compound removal stage and a methanol removal stage downstream of and in fluid communication with the volatile removal stage.

The present invention is related to a method for: reducing metals content in a Kraft pulping process comprising adding magnesium to a black liquor that is returned to the pulping operation; reducing aluminum content in a pulping process by adding magnesium to the black liquor to provide a green liquor having a specific molar ratio of magnesium:aluminum; producing or treating a green liquor having a specific molar ratio of magnesium:aluminum by adding magnesium to the black, weak black, strong black liqueurs; and producing hydrotalcite by the addition of at least 0.04-5.0 mols of magnesium:aluminum present at the weak black, strong black liqueurs, or a combination thereof. It is also provided a pulp mill comprising a digester (1), a washer (2), an optionally pulp bleaching, a weak black liquor concentrator (4), among other parts.

The present invention is related to a method for: reducing metals content in a Kraft pulping process comprising adding magnesium to a black liquor that is returned to the pulping operation; reducing aluminum content in a pulping process by adding magnesium to the black liquor to provide a green liquor having a specific molar ratio of magnesium:aluminum; producing or treating a green liquor having a specific molar ratio of magnesium:aluminum by adding magnesium to the black, weak black, strong black liqueurs; and producing hydrotalcite by the addition of at least 0.04-5.0 mols of magnesium:aluminum present at the weak black, strong black liqueurs, or a combination thereof. It is also provided a pulp mill comprising a digester (1), a washer (2), an optionally pulp bleaching, a weak black liquor concentrator (4), among other parts.

A cooking method wherein partly digested wood based cellulosic raw material is compressed during cooking to provide high molecular weight xylan, lignin and pulp.

A cooking method and a digester system wherein partly digested cellulosic fiber source is compressed during cooking to provide high molecular weight xylan, high molecular weight lignin and pulp.

A deicer composition is disclosed. The deicer composition may comprise water, a metal chloride salt, and a biopolymer composition derived from wheat straw, alfalfa, or other cereal grain straws. The biopolymer composition may include inorganic material and a copolymer comprised of lignin and polysaccharides. The biopolymer composition may have an average molecular weight of between 3500 and 5500 Daltons. The metal chloride salt may be selected from magnesium chloride, calcium chloride, and sodium chloride.

A method of treating fly ash containing sodium sulfate from a recovery boiler of a chemical pulp mill. This method includes at least the following steps: a) ash is dissolved in an aqueous solution and the pH of the solution is adjusted with alkali for precipitating impurities, b) the solution is filtered for removing the impurities containing precipitate, c) sodium sulfate is crystallized from the solution and the crystals are separated from the solution by filtering or by centrifugation, and d) the crystallized sodium sulfate is used as initial material for producing sodium and sulfur containing chemicals or as process chemical.