Biomass pelletizing process

• US 8,846,123 B2
• Filed: 08/10/2009
• Issued: 09/30/2014
• Est. Priority Date: 05/08/2009
• Status: Active Grant

• Current Assignee: Pellet Technologies LLC
• Original Assignee: Pellet Technologies LLC
• Inventors: Zeeck, James Russell
• Primary Examiner(s): Goloboy, James
• Assistant Examiner(s): HINES, LATOSHA D
• Application Number:
  US12/538,351
• Publication Number:
  US 20100281767A1
• Time in Patent Office: 1,877 Days
• Field of Search: 445/00, 445/89, 446/34, 426/442
• US Class Current: 426/442
• CPC Class Codes: C10L 5/44 on vegetable substances
• CPC Class Codes: F23K 1/00 Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
• CPC Class Codes: F23K 1/02 Mixing solid fuel with a liquid, e.g. preparing slurries
• CPC Class Codes: F23K 2201/10 Pulverizing
• CPC Class Codes: F23K 2201/20 Drying
• CPC Class Codes: F23K 2201/30 Separating
• CPC Class Codes: F23K 2201/50 Blending
• CPC Class Codes: F23K 2201/505 with additives
• CPC Class Codes: F23K 2203/103 Storage devices
• CPC Class Codes: F23K 2203/201 using pneumatic means
• CPC Class Codes: F23K 3/00 Feeding or distributing of lump or pulverulent fuel to combustion apparatus
• 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

Abstract

A process is provided using non-food or limited-feed agricultural residue and energy crops for energy production, such as ethanol or electricity generation. The agricultural plant material is harvested and baled. The bales are transported to the processing site for storage or immediate processing. The bale strings are first removed, and then the broken bales are shredded. The shredded plant material is then ground to a small size. The ground material is then pelletized to produce densified pellets of the agricultural plant material. The pellets are cooled and then stored or transported to an end user.

Claims

1. A process for utilizing agricultural crop residue material comprising:

harvesting from a field agricultural crop residue material selected from a group consisting of corn stover and soybean stubble;

then

bailing the harvested material;

then

transporting the baled material to a storage site;

then

shredding the baled material;

then

grinding the shredded material;

then

pelletizing the ground material into pellets without the use of binding additives and consisting essentially of the ground material;

transporting the pellets to a facility for use.

2. The process of claim 1 wherein the material is harvested and baled in a single pass through a field where the agricultural material is grown.

3. The process of claim 1 wherein the pelletized material has a density of 35-40 pounds per cubic foot.

4. The process of claim 1 further comprising restricting bale moisture to less than 15%.

5. The process of claim 1 further comprising storing the baled material in an outdoor storage area having a water draining base under the bales and a removable, water-resistant, fire-retardant cover over the bales.

6. The process of claim 5 further comprising providing lightning protection in the storage area.

7. The process of claim 1 wherein the pellets have less than 2% fines.

8. The process of claim 1 wherein the pellets have a durability index of at least 98.

9. The process of claim 1 wherein the pellets have a moisture content of approximately 10%.

10. The process of claim 1 wherein the harvesting step includes pre-shredding the material before baling.

11. The process of claim 1 wherein the grinding step includes a hammer mill screen and a vibrating system.

12. The process of claim 11 wherein material that does not pass through the vibrating screen is returned to the hammer mill screen for additional grinding.

13. The process of claim 1 further comprising wetting the ground material before pelletizing to control die temperature.

14. The process of claim 1 further comprising cutting the pellets prior to transportation.

15. The process of claim 1 further comprising pneumatically separating rocks and other heavy particles from the material.

16. The process of claim 1 further comprising cooling and drying the pellets using ambient air.

17. The process of claim 1 wherein the pellets are formed by extruding the ground material through a die.

18. The process of claim 1 wherein the material is ground to a density 6-8 pounds per cubic foot.

19. The process of claim 1 wherein excess ground material beyond the pelletizing capacity is reconveyed for use in the pelletizing step.

20. The process of claim 1 further comprising storing ground material in a surge bin for use in the pelletizing step.

21. The process of claim 1 wherein the ground material is fed into a straight, non-restricted die for pelletizing.

22. The process of claim 1 wherein the ground material is fed by a split conveyor under a compressed flow into a die for pelletizing.

23. The process of claim 22 wherein a conveyor feeds the ground material into a material conditioner wherein water is added before delivery to the die to control die temperature, and the conveyor returns excess material to a storage bin for future delivery to the die.

24. The process of claim 1 further comprising using the pellets for energy production.

25. A process for utilizing agricultural crop residue material for energy production comprising:

harvesting from a field agricultural crop residue material selected from a group consisting of corn stover and soybean stubble;

bailing the harvested material;

shredding the baled material;

grinding the shredded material;

pelletizing the ground material into pellets without the use of binding additives, the pellets being comprised of at least 95% of the ground material; and

wherein the ground material is fed into a straight, non-restricted die for pelletizing.

26. A process for utilizing agricultural crop residue material for energy production comprising:

harvesting from a field agricultural crop residue material selected from a group consisting of corn stover and soybean stubble;

bailing the harvested material;

shredding the baled material;

grinding the shredded material;

pelletizing the ground material into pellets consisting essentially of the ground material; and

wherein the ground material is fed under a compressed flow through a split conveyor into a die for pelletizing.

27. A process for utilizing agricultural crop residue material for energy production comprising:

harvesting from a field agricultural crop residue material selected from a group consisting of corn stover and soybean stubble;

bailing the harvested material;

shredding the baled material;

grinding the shredded material;

pelletizing the ground material into pellets consisting essentially of the ground material;

providing an air flow for assisting the flow of material through the grinding and pelletizing steps.