A method and apparatus for protecting a furnace floor of a black liquor recovery boiler, where the furnace floor is covered by a protective layer, the protective layer being formed of a salt mixture including at least two different salts.

The present invention relates to a process for obtaining cellulose or a mixture containing at least cellulose and at least lignocellulose from at least one substrate that is at least to some extent amenable to fermentation comprising at least the steps of (1) to (3) and optionally (4), namely conversion of the substrate via addition of at least one inorganic base into an aqueous mixture with pH≥8.5 (step 1), ultrasound treatment of the aqueous mixture obtained after step (1) (step 2), separation of the aqueous mixture obtained after step (2) into a liquid aqueous phase and a disperse mixture containing, cellulose or a mixture containing at least cellulose and at least lignocellulose (step 3) and optionally purification of the disperse mixture obtained after step (3) containing cellulose or of the mixture containing at least cellulose and at least lignocellulose (step 4), where step (1) and step (2) of the process respectively are carried out at a temperature <100° C. and Where the ultrasound treatment in step (2) takes place in one or more treatment phases, where the duration of a treatment phase is in the range from 0.2 to 60 seconds and each treatment phase is carried out with a sonotrode frequency in the range from 14 to 22 kHz.

The present invention relates to a process for obtaining cellulose or a mixture containing at least cellulose and at least lignocellulose from at least one substrate that is at least to some extent amenable to fermentation comprising at least the steps of (1) to (3) and optionally (4), namely conversion of the substrate via addition of at least one inorganic base into an aqueous mixture with pH≥8.5 (step 1), ultrasound treatment of the aqueous mixture obtained after step (1) (step 2), separation of the aqueous mixture obtained after step (2) into a liquid aqueous phase and a disperse mixture containing, cellulose or a mixture containing at least cellulose and at least lignocellulose (step 3) and optionally purification of the disperse mixture obtained after step (3) containing cellulose or of the mixture containing at least cellulose and at least lignocellulose (step 4), where step (1) and step (2) of the process respectively are carried out at a temperature <100° C. and Where the ultrasound treatment in step (2) takes place in one or more treatment phases, where the duration of a treatment phase is in the range from 0.2 to 60 seconds and each treatment phase is carried out with a sonotrode frequency in the range from 14 to 22 kHz.

A method for removing hydrogen sulphide ions (HS.sup.−) from a liquor (300) of a pulp mill process, the method comprising pumping the liquor (300) to an injector arrangement (710) using a pump arrangement (720) such that the pumping of the liquor (300) through a jet nozzle (115) generates suction at a gas inlet (130), whereby reagent gas (310) is mixed with the liquor (300), and letting out the treated liquor (300) from the injector arrangement (710) to a vessel (200). In this way, the liquor (300) is treated to form at least partly treated liquor (300). A corresponding use of an injector arrangement. A system for performing the method.

A method for removing hydrogen sulphide ions (HS.sup.−) from a liquor (300) of a pulp mill process, the method comprising pumping the liquor (300) to an injector arrangement (710) using a pump arrangement (720) such that the pumping of the liquor (300) through a jet nozzle (115) generates suction at a gas inlet (130), whereby reagent gas (310) is mixed with the liquor (300), and letting out the treated liquor (300) from the injector arrangement (710) to a vessel (200). In this way, the liquor (300) is treated to form at least partly treated liquor (300). A corresponding use of an injector arrangement. A system for performing the method.

An object of the present invention is to provide a method for easily extracting and efficiently recovering xylan from wood.

A xylan-containing material is produced by a method comprising the steps of: (a) adding an acid and/or carbon dioxide to a black liquor discharged during a soda cooking step of wood chips including hardwood chips to adjust the pH of the black liquor to be in the range of 1 to 9, thereby giving a suspension; (b) dehydrating and washing an insoluble matter generated in the suspension to separately collect the insoluble matter; and (c) adding an organic solvent to the insoluble matter obtained at the step (b) to give a suspension, and separately collecting a xylan-containing material made of the insoluble matter present in the suspension by solid/liquid separation.

The method is for separation of lignin from original black liquor (BL.sub.IN) that has a first precipitation stage (PR) for precipitation of lignin by a first acidification using acidifier AC.sub.1, preferably using CO.sub.2, at alkaline conditions, then separating a lignin cake with subsequent suspension of the lignin cake in a strong acid in order to leach our metals from the lignin followed by dewatering and obtaining a clean lignin product LP. The process further is improved by intensified hydrolysis of lignin cake such that most of the carbohydrates are broken down to dissolvable monomers that could be separated from the lignin in the filtrate from a filtering stage subsequent to the hydrolysis. The improved hydrolysis could reduce as much as 90% of the carbohydrate content using a moderately increased temperature and increased charge of acidifier while avoiding any larger lignin yield losses.

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.

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 method is for separation of lignin from original black liquor (BL.sub.IN) that has a first precipitation phase (PR1/PR2) for precipitation of lignin by a first acidification using acidifier, CO.sub.2, at alkaline conditions, then separating a lignin cake with subsequent suspension of the lignin cake in a strong acid in order to leach out metals from the lignin followed by dewatering and obtaining a clean lignin product LP. Lignin germ particles (LG) are added to the original black liquor in the first precipitation stage, preferably between two phases in said precipitation stage, in order to increase lignin particle growth on such lignin germ particles instead of spontaneous nucleation of lignin particles in said original black liquor. This results in improved filterability in subsequent dewatering and lignin cake formation and hence an increased lignin yield.