Method for cooling and detoxifying biomass
AssigneeValmet Corporation
InventorsPeter Björklund, Andreas Averheim
Life of this patent
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Abstract
The present invention relates to an improved method and device for treating biomass in which thermally treated biomass is discharged from a pressurized reactor and introduced into a blow tank and then a flash tank, wherein the absolute pressure in the blow tank is maintained above atmospheric pressure and the absolute pressure in the flash tank is maintained below atmospheric pressure. The slurry of biomass separated in the flash tank is then enzymatically treated. The heat from the thermally treated biomass is recovered from the latent heat of a vaporous aqueous stream withdrawn from the blow tank.
Claims19
A method for treating biomass comprising the steps of
- (a) feeding lignocellulosic biomass to a pressurized reactor;
- (b) supplying steam to the pressurized reactor and at least partially condensing said steam in the pressurized reactor;
- (c) hydrolysing hemicellulose sugars of said biomass with said at least partially condensed steam in the pressurized reactor;
- (d) discharging said hydrolyzed biomass from the pressurized reactor into a blow tank by steam explosion to produce a steam exploded biomass;
- (e) diluting the steam exploded biomass in the blow tank with an aqueous diluent to a pumpable aqueous slurry;
- (f) pumping said aqueous slurry from the blow tank to a flash-tank for evaporative cooling to produce a cooled aqueous slurry;
- (g) discharging the cooled aqueous slurry from the flash tank as discharged cooled aqueous slurry stream;
- (h) treating the discharged cooled aqueous slurry stream with an enzyme;
- characterized by
- withdrawing a first vaporous aqueous stream from the blow tank for maintaining the absolute pressure in the blow tank above the atmospheric pressure;
- recovering the latent heat from the first vaporous aqueous stream;
- and
- withdrawing a second vaporous aqueous stream from the flash tank for maintaining the absolute pressure in the flash tank below the atmospheric pressure.
A device for treating biomass comprising
- a biomass feeding system;
- a pressurized reactor for thermally treating the biomass
- a blow tank;
- a discharging system for discharging the hydrolyzed biomass from the pressurized reactor to the blow tank by steam explosion;
- a flash tank;
- and
- a unit for enzymatically treating treated cooled aqueous slurry stream of biomass discharged from the flash tank;
- wherein
- the blow tank comprises
- means for maintaining the absolute pressure in the blow tank above atmospheric pressure;
- at least one injection port for injecting an aqueous diluent;
- at least one discharge port for discharging a first vaporous aqueous stream;
- at least one discharge port for discharging an aqueous slurry stream comprising the steam exploded biomass;
- the flash tank comprises
- means for maintaining the absolute pressure in the flash tank below atmospheric pressure, preferably below 0.5 bar (a);
- at least one discharge port for discharging a second vaporous aqueous stream;
- at least one discharge port for discharging a cooled aqueous slurry stream, and the device further comprises a unit for recovering the latent heat from said first vaporous aqueous stream withdrawn from the blow tank.
Dependencies are inferred from the claim text.