Method for the gasification of a black liquor

Patent metadata

Field	Value
Publication number	US-12473689-B2
Application number	US-202118253648-A
Country	US
Kind code	B2
Filing date	Nov 22, 2021
Priority date	Nov 23, 2020
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

A method for transforming a black liquor, comprising the following steps: a) supplying a black liquor, b) gasifying the black liquor by means of supercritical water gasification in the presence of a hydrogenated carbon-free fuel, by means of which reaction products are formed, c) cooling the reaction products, by means of which a gaseous mixture is obtained which comprises at least methane and a green liquor comprising at least sulphur in the form of NaHS, Na2S and H2S.

First claim

What is claimed is:

1 . A method for transforming a black liquor comprising the following steps:
a) supplying a black liquor, b) carrying out a supercritical water gasification of the black liquor, whereby reaction products are formed, c) cooling the reaction products, whereby are obtained a gaseous mixture is obtained comprising at least methane, and a green liquor comprising at least sulphur in the form of NaHS, Na 2 S and H 2 S, wherein the supercritical water gasification is carried out by addition in step b) of a carbon-free hydrogenated fuel.

2 . The method according to claim 1 , wherein the carbon-free hydrogenated fuel is dihydrogen.

3 . The method according to claim 1 , wherein the carbon-free hydrogenated fuel is hydrazine.

4 . The method according to claim 1 , wherein the carbon-free hydrogenated fuel is ammonia.

5 . The method according to claim 1 , wherein the supercritical water gasification is carried out by addition in step b) of the carbon-free hydrogenated fuel and of an oxidant.

6 . The method according to claim 5 , wherein the oxidant is dioxygen, H 2 O 2 or a nitrate.

7 . The method according to claim 5 , wherein the carbon-free hydrogenated fuel/oxidant molar ratio ranges from 2 to 10.

8 . The method according to claim 7 , wherein the carbon-free hydrogenated fuel/oxidant molar ratio ranges from 5 to 7.

9 . The method according to claim 1 , wherein the temperature during the supercritical water gasification step b) is at least 600° C.

10 . The method according to claim 9 , wherein the temperature during the supercritical water gasification step b) is between 700° C. and 800° C.

11 . The method according to claim 1 , wherein the pressure during the supercritical water gasification step b) is at least 25 MPa.

12 . The method according to claim 11 , wherein the pressure during the supercritical water gasification step b) is between 25 MPa and 350 MPa.

13 . The method according to claim 12 , wherein the pressure during the supercritical water gasification step b) is between 300 MPa and 350 MPa.

14 . The method according to claim 1 , wherein the cooling during step c) is carried out at a temperature comprised between 25° C. and 80° C. and/or the pressure is comprised between 1 and 20 MPa.

15 . The method according to claim 1 , wherein the method is carried out without a catalyst.

Assignees

• Commissariat Energie Atomique

Inventors

• Haarlemmer Geert

Classifications

• D21C11/125

  Decomposition of the pulp liquors in reducing atmosphere or in the absence of oxidants, i.e. gasification or pyrolysis · CPC title

• D21C11/0092

  Substances modifying the evaporation, combustion, or thermal decomposition processes of black liquor (treatment of solid substances (ash) separated from combustion gases D21C11/066; avoiding scale-forming during evaporation D21C11/106) · CPC title

• D21C11/0057

  Oxidation of liquors, e.g. in order to reduce the losses of sulfur compounds, followed by evaporation or combustion if the liquor in question is a black liquor (deodorisation of gases D21C11/08; combustion D21C11/12, D21C11/14) · CPC title

• D21C11/0042

  Fractionating or concentration of spent liquors by special methods (concentration by evaporation D21C11/10) · CPC title

• C10J3/78

  High-pressure apparatus · CPC title