In some embodiments, a method may include treating pulp. The method may include contacting a wood pulp with a singlet oxygen source. The method may include contacting the wood pulp with an alkaline peroxide source. The singlet oxygen source may include a peracetate oxidant solution and generating a reactive oxygen species. The peracetate oxidant solution may include peracetate anions and a peracid. In some embodiments, the peracetate solution may include a pH from about pH 10 to about pH 12. In some embodiments, the peracetate solution has a molar ratio of peracetate anions to peracid ranging from about 60:1 to about 6000:1. In some embodiments, the peracetate solution has a molar ratio of peracetate to hydrogen peroxide of greater than about 16:1. The peracetate oxidant solution may provide enhanced treatment methods of bleaching, brightening, and delignifying pulp fibers involving the use of peracetate oxidant solutions.

Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm.sup.3 to 5 mm.sup.3, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH).sub.2); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

Method for purifying crude tall oil soap from black liquor, wherein a washing liquid is used, which washing liquid is either pH-regulated residual liquid from a tall oil producing processing step (180) or a pH-regulated aqueous solution of ash, wherein black liquor-containing crude tall oil soap is mixed with said washing liquid, and wherein the crude tall oil soap is then separated out from the resulting mixture. The method comprises the steps 1. performing a first coarse separation (120,130) of crude tall oil soap from said black liquor, so that a first crude tall oil soap fraction is formed; 2. mixing (140) the first crude tall oil soap fraction with washing liquid, so that a first diluted fraction is formed; and 3. performing a separation (150) of the first diluted fraction using a first centrifugal separator of purificator type, so that a second crude tall oil soap fraction is achieved. The second crude tall oil soap fraction comprises smaller contents of black liquor than the first crude tall oil soap fraction. The invention also relates to a system.

There is provided a defoaming agent having excellent defoaming persistence. The defoaming agent includes; hydrophobic silica having a hydrophobicity (M.sub.X) of 50 to 85, and a rate of change (M.sub.Y/M.sub.X) of a hydrophobicity (M.sub.Y) after immersion for 1 hour in a methanol/ion-exchange aqueous solution (volume ratio of 80/20) of sodium hydroxide with a pH of 13 at 25° C. to the hydrophobicity (M.sub.X) of 0.8 to 1.0; and at least one kind of liquid selected from the group consisting of a hydrocarbon oil, a non-reactive silicone oil and a polyoxyalkylene compound.

The invention discloses a process for treating black liquor comprising pyrolysing black liquor in a fluidized bed reactor to obtain solid particles and pyrolysed black liquor gas, heating the solid mass, returning the heated solid mass to the fluidized bed reactor for use in the pyrolysis reaction; condensing the pyrolysed black liquor gas to obtain a condensate and recover heat and a residual gas released during condensation for heating the solid mass to a predetermined temperature for that is required for the pyrolysis.

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 present invention relates to a process for purifying, such as salt/ion depletion, and/or ash reduction,and/or sulphur removal, and/or free sugar depletion,and/or VOC depletion or fractionating,preferably by using dewatering, of a slurry comprising a lignin or lignin derivative or a combination thereof. A lignin or lignin derivative obtainable from said process and uses thereof are also disclosed.

The present invention relates to a process for purifying, such as salt/ion depletion, and/or ash reduction,and/or sulphur removal, and/or free sugar depletion,and/or VOC depletion or fractionating,preferably by using dewatering, of a slurry comprising a lignin or lignin derivative or a combination thereof. A lignin or lignin derivative obtainable from said process and uses thereof are also disclosed.

The present invention relates to a method of treating biomass, comprising providing a lignocellulosic biomass feedstock; contacting the biomass feedstock in a mixture, which is formed by the biomass, water and an alkaline agent, with an oxidizing agent at an elevated temperature; and continuing the contacting of the biomass feedstock with the oxidizing agent until a notable part of the lignin is solubilised. The step of providing the biomass feedstock comprises contacting a biomass raw-material containing cellulose, hemicellulose and lignin in an aqueous phase with an alkaline agent; continuing the contacting of the biomass with the alkaline agent until a significant portion of the hemicellulose is dissolved in the aqueous phase to provide a modified biomass; recovering the modified biomass; optionally opening the structure of the modified biomass by mechanical treatment; and using the modified biomass as a lignocellulosic biomass feedstock. Treating the biomass provides hemicellulose, lignin and cellulose fractions that have a multitude of applications in the bioeconomy.

Digestion of cellulosic biomass solids may be complicated by release of lignin therefrom. Methods and systems for processing a reaction product containing lignin-derived products, such as phenolics, can comprise hydrotreating the reaction product to convert the lignin-derived products to desired higher molecular weight compounds. The methods and systems can further include separating the higher molecular weight compounds from unconverted products, such as unconverted phenolics, and recycling the unconverted phenolics for use as at least a portion of the digestion solvent and for further conversion to desired higher molecular weight compounds with additional hydrotreatment. The methods and systems can further include a further hydrotreatment step configured for additional lignin conversion and/or a further hydrotreatment step configured for generating hydrogen.