Method for gasifying biomass
View Patent ↗Gasification method comprising the following steps of: a) bringing, in a main reactor, beads made of steel, an alloy, glass or ceramic, at a temperature between 600° C. and 1,000° C., into contact with a feedstock mixture comprising water and a biomass, the biomass comprising an organic part and salts, the main reactor being pressurised to more than 224 bar and at a temperature above 200° C. b) gasifying the organic part in the presence of the beads, thereby forming a gaseous phase, an aqueous phase and a solid residue, and whereby the salts precipitate on the beads, forming a salt shell covering the beads, c) separating the beads from the organic part, d) regenerating the beads.
1 . A method for gasifying biomass comprising the steps of:
a) in a main reactor, bringing beads that have been pre-heated to a temperature between 600° C. and 1,000° C. into contact with a feedstock mixture comprising water and a biomass, the biomass comprising an organic part and salts,
wherein the beads are made of a material that is selected from steel, a metal alloy, glass or a ceramic,
and wherein the main reactor is pressurised to more than 222 bar;
b) at least partially gasifying the organic part, in the presence of the beads at a temperature above 374° C. and at a pressure above 222 bar, thereby forming a gaseous phase, an aqueous phase and a solid residue, and whereby the salts precipitate on the beads, forming a salt shell covering the beads;
c) separating the beads covered by the salt shell from any recoverable organic part; and
d) regenerating the beads.
2 . The method according to claim 1 , wherein in step a), the main reactor is heated to a temperature above 200° C. and below 374° C.
3 . The method according to claim 1 , wherein step d) comprises the following sub-steps:
d1) removing the salt shell of the beads; and
d2) pre-heating the beads to a temperature between 600° C. and 1,000° C.
4 . The method according to claim 3 , wherein step d1) is carried out by washing the beads with an aqueous solution at a temperature below 374° C., whereby the salts are dissolved.
5 . The method according to claim 3 , wherein sub-step d2) is carried out in a heating reactor positioned between a collection chamber and the main reactor.
6 . The method according to claim 3 , wherein during sub-step d1), the beads are washed with the aqueous phase from step b).
7 . The method according to claim 3 , wherein the solid residue from step b) is used to pre-heat the beads to a temperature between 600° C. and 1,000° C. in sub-step d2).
8 . The method according to claim 1 , wherein the biomass has a moisture content of over 50%, whereby the biomass can be ground prior to step a).
9 . The method according to claim 8 , wherein the biomass comprises microalgae, macroalgae, agricultural waste, household waste, sludge from wastewater treatment plants or wastewater.
10 . The method according to claim 1 , wherein the beads have a diameter of from 500 μm to 2 mm.
11 . The method according to claim 1 , wherein the method further comprises a step in which oils contained in the biomass are dissolved by injecting ethanol into the main reactor.
12 . The method according to claim 1 , wherein the method further comprises a subsequent step e) in which a further gasification step is carried out at a pressure above 222 bar in order to gasify the organic part not gasified in step b), the temperature in step e) being between 60° and 700° C. or step e) being carried out in the presence of a catalyst at a temperature below 500° C.
13 . The method according to claim 1 , wherein, in step b), the organic part is gasified in a gasification reactor.
14 . The method according to claim 13 , wherein the gasification reactor is in fluid communication with a collection chamber and in that, in step c), the beads are collected in the collection chamber.
15 . The method according to claim 1 , wherein the feedstock mixture is preheated to a temperature from 150° C. to 250° C., before step a).