Various techniques are described for enhanced combustion of hot water extraction (HWE) derived liquor. For example, the HWE derived liquor can be pre-treated prior to introduction into a combustion chamber. The pre-treatment can include subjecting HWE derived liquor to filtration to remove suspended solids, evaporation to produce a first stage concentrated HWE liquor; additional concentration to produce a second stage concentrated HWE liquor; additional filtration to remove additional suspended solids; and pre-heating to produce a preheated HWE liquor. The preheated HWE liquor can be atomized and combined with pre-heated combustion air supplied into a combustion chamber to effect combustion of the HWE derived liquor.

The present disclosure generally relates to a method for controlled pretreatment of lignocellulosic biomass. The method comprises the steps of: Pretreating (S10) a lignocellulosic biomass material in a pretreatment arrangement, the pretreating comprising impregnating (S10A) the lignocellulosic biomass with an SO2 feed in an impregnation vessel of the pretreatment arrangement; collecting (S20) a number of process parameters of the pretreatment, which process parameters include at least a feed parameter related to the total amount of lignocellulosic biomass input to the pretreatment arrangement, and a dry matter parameter related to the dry matter content of lignocellulosic biomass input to the pretreatment arrangement; and adjusting (S30) the SO2 feed in response to the process parameters.

The invention provides a method and a system for separating lignin from a lignin containing liquid medium, such as pulp mill black liquor, and treating the separated lignin. The method comprises at least the following steps: a) a precipitation stage (1), wherein a pH lowering agent (A) is added to the lignin containing slurry for precipitating lignin, b) followed by a first separation stage (2), wherein the precipitated lignin is separated as a lignin cake from the remaining liquid phase of the lignin containing slurry, c) a suspending stage (3), wherein the lignin cake is suspended for obtaining a lignin suspension, d) a hydrothermal carbonization stage (4), wherein the lignin suspension is treated for obtaining a slurry of carbon containing material, and e) a second separation stage (5), wherein the carbon containing material is separated from the slurry.

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.

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.

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 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.