Lignoboost Ab

Valmet Ab

C-green Technology Ab

Valmet Aktiebolag

C-green Ab

Fredrik Öhman

Per Tomani

Hans Theliander

Peter Axegard

Fredrik Lundqvist

Henrik Wallmo

Martin Wimby

Erik Oden

Mattias Svensson

Lars-Erik Åkerlund

Magnus Norgren

Peter Axegård

Erik Odén

There is provided a method of hydrothermal carbonization of a sludge from a wastewater treatment plant, comprising the steps of: preheating the sludge with at least one first steam fraction to obtain a preheated sludge; further heating the preheated sludge with a second steam fraction to obtain a heated sludge; subjecting the heated sludge to hydrothermal carbonization (HTC) in a reactor to obtain a HTC-treated slurry; mixing the HTC-treated slurry with an oxidizing agent, such as oxygen gas, to obtain a wet-oxidized slurry; subjecting the wet-oxidized slurry to flashing to obtain the second steam fraction and a pre-cooled slurry; subjecting the pre-cooled slurry to flashing in at least one step to obtain the at least one first steam fraction and a cooled slurry; separating the cooled slurry into a liquid fraction and a solids fraction; and routing the liquid fraction to the wastewater treatment plant for further treatment, wherein the second steam fraction is used for heating preheated sludge to the temperature of the HTC reaction. A corresponding system is also provided.

Method and system for hydrothermal carbonization and wet oxidation of sludge

There is provided a method of treatment of sludge, such as municipal or industrial sludge from a wastewater treatment plant, comprising the steps of: &#x2014;preheating an incoming sludge with at least one steam fraction, preferably by direct steam injection, to obtain a preheated sludge; &#x2014;further heating the preheated sludge with a high-temperature steam fraction, preferably by direct steam injection, to obtain a heated sludge; &#x2014;hydrothermal carbonization (HTC) of the heated sludge to obtain a HTC-treated sludge; &#x2014;separating a particle-lean fraction from the HTC-treated sludge; &#x2014;wet oxidation of the particle-lean fraction to obtain a heated particle-lean fraction; &#x2014;subjecting the heated particle-lean fraction to a first flashing to obtain the high-temperature steam fraction used in the further heating step; &#x2014;separating a particle-rich fraction from the HTC-treated sludge; &#x2014;subjecting the particle-rich fraction to flashing to obtain at least one steam fraction that is used in the preheating step and a cooled particle-rich fraction.

Method for oxidation of a liquid phase in a hydrothermal carbonization process

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 method is for separation of lignin from original black liquor (BL) and has the following phases in sequence. A first precipitation phase (PR) for precipitation of lignin by a first acidification of the original black liquor by adding a first acid or mixture of acids (G) followed by a first storage phase wherein precipitated lignin particles are allowed to increase in size, followed by a second precipitation phase (PR) for precipitation of lignin by a further acidification of the original black liquor by adding a second acid or mixture of acids (G). By retaining the acidified black liquor for at least 25 minutes in the storage phase are the precipitated lignin particles allowed to grow in size and the filterability is improved considerably.

Method for lignin separation from black liquor involving multiple acidification steps

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

Gävle, Sweden

Fredrik Öhman