Lignoboost Ab

Valmet Ab

Valmet Aktiebolag

Sodra Skogsagarna Ekonomisk Forening

Hans Theliander

Per Tomani

Fredrik Öhman

Peter Axegard

Harald Brelid

Peter Axegård

Fredrik Wernersson

Kristoffer Lund

Magnus Norgren

Fredrik ÖHman

The method is for separation of lignin from original black liquor (BL) that has a first precipitation phase (PR1/PR2) for precipitation of lignin by a first acidification using acidifier, CO, 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.

Method for lignin separation from black liquor

The method is for controlling a sodium and sulphur balance of a pulp mill while separating lignin from black liquor. Lignin is precipitated by using an acid followed by filtration. The lignin filter cake thus obtained is re-suspended in acidic liquid and dewatered to form a second cake. The filtrate obtained after dewatering of the second cake is returned for washing and suspension of the first cake. Sodium sulphate-rich ESP (electrostatic precipitator) dust produced in the recovery boiler is used in the washing of the precipitated lignin cake.

Method for separating lignin from black liquor, a lignin product, and use of a lignin product for the production of fuels or materials

The present invention relates to a process for producing an oxidized cellulose pulp fibrillar network and a composite with lignocellulosic fibers comprising the following steps: (a) oxidizing a cellulose pulp to obtain about 0.3 to 2.5 mmol carboxylic groups per gram cellulose pulp; and about 0.1 to 5.0 mmol aldehyde groups per gram cellulose pulp; (b) homogenization of the cellulose pulp of step (a) wherein the cellulose fibers are refined to provide a cellulose pulp comprising 0-50% of fibers having an average length 0.7 mm-2.1 mm; and 50-100% of fibers having a particle size of 0.05-500 micrometer (&#x3bc;m); and optionally (c) combining with lignocellulosic fiber. Also step (d) drying of the cellulose pulp obtained by step (b) or step (c) may be included in the process.

Process for production of oxidised cellulose pulp

A method for precipitating (separation) of lignin, using small amounts of acidifying agents, whereby a lignin product or an intermediate lignin product is obtained which can be used as fuel or chemical feed stock (or as a chemical or a raw material for further refining), from a lignin containing liquid/slurry, such as black liquor. A method for separation of lignin from a lignin containing liquid/slurry, such as black liquor, whereby a more pure lignin is obtained, a lignin product or an intermediate lignin product obtainable by the above methods, and use, preferably for the production of heat or for use as chemical, of the lignin product or intermediate lignin product are also disclosed.

Method for separating lignin from a lignin containing liquid/slurry

Method for separating lignin from black liquor includes the following steps: a) precipitating lignin by acidifying black liquor and thereupon dewatering, b) suspending the lignin filter cake obtained in step a) to obtain a second lignin suspension and adjusting the pH level to approximately that of the washing water of step d) below, c) dewatering of the second lignin suspension, d) adding washing water and performing a displacement washing at substantially constant conditions without any dramatic gradients in the pH, and e) dewatering the lignin cake produced in step d) into a high dryness and displacing the remaining washing liquid in the filter cake, whereby a lignin product is obtained which has an even higher dryness after the displacement washing of step d). The lignin product or an intermediate lignin product obtained by the method, and its use, preferably for the production of heat or chemicals is also disclosed.

Method for separating lignin from black liquor

A method for controlling the sodium and sulphur balance of a pulp mill while separating lignin from black liquor, and also a lignin product or an intermediate lignin product obtainable by the method. The present invention also provides use of a lignin product or an intermediate lignin product for the production of fuel (solid, gaseous or liquid) or materials.

Growing community of inventors

Göteborg, Sweden

Hans Theliander