High temperature bio-char carbonization and micron grinding and classification for inclusion into master batch polymerization

Patent metadata

Field	Value
Publication number	US-11767474-B2
Application number	US-202117248865-A
Country	US
Kind code	B2
Filing date	Feb 11, 2021
Priority date	Apr 27, 2018
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A thermal process for carbonizing hemp and reducing particle size, mechanically, by grinding or milling said carbonized hemp materials to generate a precise particle size hemp char and combining the hemp char particles with a polymer into a master batch.

First claim

What is claimed is:

1. A process for creating a mixture of micron-sized charred hemp comprising:
rough cutting a portion of hemp stalk said hemp stalk comprising hemp hurd and hemp fibers;
charring the portion of hemp stalk at a temperature of greater than 1100° C. for a period of at least one hour to create a char material;
milling the char material by air jet milling, grinding, or ball milling to create a milled char having an irregular polyhedron shape; and
collecting the milled char.

2. The process of claim 1 further comprising a first step of drying the hemp stalk before the rough cutting step.

3. The process of claim 1 , wherein the temperature of greater than 1100° C. is held for at least one hour, and wherein the charring process is performed by addition of a non-oxygen gas to a heating chamber.

4. The process of claim 1 , wherein the milling is performed in a high energy ball mill.

5. The process of claim 1 , wherein the milled char is admixed with a polymer.

6. The process of claim 1 , wherein the milled char is classified in a classifying system to create a desired particle size and wherein the desired fraction from the classification system comprises a 95% specific classification size of less than 2 microns and a 95% bell curve of 1.5 microns.

7. A process for creating a master batch comprising a plurality of hemp char particles and at least one polymer comprising:
carbonizing a portion of a hemp material, said hemp material comprising hemp hurd and hemp fibers in a furnace, said furnace being flushed with nitrogen and then heated to a temperature of greater than 1100° C.;
wherein the temperature of greater than 1100° C. is held for at least 60 minutes;
maintaining nitrogen flow over the at least 60 minutes to maintain a low oxygen environment to create a char;
removing the char from the furnace and allowing it to cool;
milling the char by a milling process for a period sufficient to reduce the char into a plurality of char particles having an irregular polyhedron shape by air jet milling or ball milling;
combining the char particles with the at least one polymer, wherein the ratio of char particles to polymer is between 10:90 and 50:50; and
mixing the at least one polymer and the char particles to form the master batch.

8. The method of claim 7 , wherein at least 90% of all of the char particles are less than 10 microns in size.

9. The method of claim 7 , wherein the average particle size of all of the char particles is between 1 and 2 microns, and wherein at least 95% of all of the char particles are less than 2 microns in size.

10. The method of claim 7 , wherein the milling process is a wet milling process.

11. The method of claim 10 , wherein the wet milling process comprises a nonaqueous solvent.

12. The method of claim 7 , wherein the char particles are classified to remove particles of more than 2 microns in size.

13. A process of forming a plurality of charred hemp particles having more than 50% of particles formed between 1 and 2 microns in size comprising:
drying cut hemp stalk on a field for a period of less than 7 days, said hemp stalk comprising hemp hurd and hemp fibers;
pyrolyzing the dried hemp stalk at a temperature of greater than 1100° C. to create a char;
adding the char to a grinding vessel and mechanically grinding the char for a period of between 1 and 16 hours by grinding, air jet milling, or ball milling the char to form a ground char having an irregular polyhedron shape;
screening the ground char with a 2-micron screen to create a screened char of less than 2 microns; and
capturing the screened char of less than 2 microns.

14. The process of claim 13 , wherein the grinding vessel is a steel vessel with steel grinding balls.

15. The process of claim 13 , wherein the grinding is dry grinding.

16. The process of claim 13 , wherein the grinding is wet grinding.

17. The process of claim 16 , wherein the wet grinding is performed for a first duration of between 1 and 16 hours and is followed by a step of drying to create an agglomerated ground char and regrinding the agglomerated ground char in a dry grinding process.

18. The process of claim 15 further comprising separating the material resulting from the 2-micron screen into particles smaller than 2 microns and particles larger than 2 microns and regrinding the particles larger than 2 microns.

Assignees

• Univ Jefferson

Inventors

• Sunderland Mark

Classifications

• C10B53/02 Primary

  of cellulose-containing material (production of pyroligneous acid C10C5/00) · CPC title

• B02C17/186

  Adding fluid, other than for crushing by fluid energy · CPC title

• B02C23/12

  with return of oversize material to crushing or disintegrating zone · CPC title

• C08J3/226 Primary

  using a polymer as a carrier · CPC title

• C08K3/04

  Carbon · CPC title