Post torrefaction biomass pelletization

• US 9,988,588 B2
• Filed: 06/15/2015
• Issued: 06/05/2018
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: Biomass Secure Power Inc.
• Original Assignee: River Basin Energy, Inc. (Biomass Secure Power Inc.)
• Inventors: Sethi, Vijay, Camper, Clinton B., Isaak, Jerrod D.
• Primary Examiner(s): Toomer, Cephia D
• Application Number:
  US14/740,041
• Publication Number:
  US 20150275115A1
• Time in Patent Office: 1,086 Days
• CPC Class Codes: C10B 49/10 according to the "fluidised bed" technique
• CPC Class Codes: C10B 53/02 of cellulose-containing material production of pyroligneous acid C10C5/00
• CPC Class Codes: C10L 2290/02 Combustion or pyrolysis
• CPC Class Codes: C10L 2290/06 Heat exchange, direct or indirect
• CPC Class Codes: C10L 2290/08 Drying or removing water
• CPC Class Codes: C10L 2290/20 Coating of a fuel as a whole or of a fuel component
• CPC Class Codes: C10L 2290/28 Cutting, disintegrating, shredding or grinding
• CPC Class Codes: C10L 2290/30 Pressing, compressing or compacting
• CPC Class Codes: C10L 2290/50 Screws or pistons for moving along solids
• CPC Class Codes: C10L 2290/58 Control or regulation of the fuel preparation of upgrading process
• CPC Class Codes: C10L 5/08 without the aid of extraneous binders briquetting peat C10F
• CPC Class Codes: C10L 5/32 Coating
• CPC Class Codes: C10L 5/361 Briquettes
• CPC Class Codes: C10L 5/363 Pellets or granulates
• CPC Class Codes: C10L 5/447 Carbonized vegetable substances, e.g. charcoal, or produced by hydrothermal carbonization of biomass
• CPC Class Codes: C10L 9/083 Torrefaction
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02P 20/145 the feedstock being materials of biological origin

Abstract

A process for torrefaction of biomass is provided in which biomass are passed into a fluidized bed or a non-fluidized bed reactor and heated to a predetermined temperature in an oxidizing environment. The dried biomass is then fed to a cooler where the temperature of the product is reduced to approximately 100 degrees Fahrenheit.

Claims

1. A process for biomass torrefaction, comprising:

adding biomass to a reactor;

adding a first gas to said reactor, wherein the first gas comprises an oxygen concentration from about 10 vol % to about 21 vol %;

controlling an oxygen concentration of a second gas exiting said reactor, wherein said oxygen concentration of the second gas is less than about 8 vol %;

initiating heating of said biomass by increasing a temperature of said reactor;

heating said biomass to a biomass temperature between about 250°

C. to about 325°

C. by partial combustion of said biomass with oxygen in the first gas in said reactor;

maintaining the biomass temperature within said reactor for a predetermined time by spraying water into said reactor, whereby a portion of moisture is removed from said biomass, volatile organic compounds associated with said biomass are removed, and said biomass is torrefied to produce a torrefied biomass with a moisture content from about 0 wt % to about 2 wt %; and

increasing the density of said torrefied biomass at a temperature of about 90°

C. to 200°

C. to form a densified biomass.

2. The process of claim 1, wherein said densified biomass is hydrophobic.

3. The process of claim 1, wherein said densified biomass has a glassy surface.

4. The process of claim 1, wherein said densified biomass contains a distribution of lignins.

5. The process of claim 1, wherein said densified biomass possesses a coating.

6. The process of claim 1, wherein said densified biomass is in the form of pellets or briquettes.

7. The process of claim 6, wherein the pellets have a maximum size of about 1.5 in.×

1.5 in.×

0.4 in.

8. The process of claim 1, wherein binders are not added to the torrefied biomass.

9. The process of claim 1, further comprising adding a binder to the torrefied biomass.

10. The process of claim 1, further comprising feeding said torrefied biomass directly to a densification device, wherein the temperature of the torrefied biomass is maintained.

11. The process of claim 1, wherein a temperature of the reactor is between about 270°

C. and about 300°

C.

12. The process of claim 1, wherein said biomass has an average moisture content from about 10% to about 50%.

13. The process of claim 1, further comprising coating the densified biomass.

14. The process of claim 1, wherein the densified biomass has a diameter of about 0.25 inches.

15. The process of claim 1, further comprising combining a binder with the torrefied biomass in a mixer prior to the densification step, and wherein the binder is at least one of an unprocessed lignin, a ligno-sulfonate, a coal, a bitumen, a molasses, or a raw biomass.

16. The process of claim 1, further comprising grinding the torrefied biomass before the densification step.

17. The process of claim 16, wherein the grinding step occurs at a temperature between about 90°

C. and about 200°

C.

18. The process of claim 1, further comprising cooling the densified biomass to a temperature of about 50°

C.

19. The process of claim 1, wherein said biomass is selected from the group consisting of wood, forestry waste, energy crops, municipal waste, plant material, straw, agricultural waste, and combinations thereof.