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

Patent metadata

Field	Value
Publication number	US-10619102-B2
Application number	US-201916395515-A
Country	US
Kind code	B2
Filing date	Apr 26, 2019
Priority date	Apr 27, 2018
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

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 portion of hemp stalk comprising fiber and hurd materials; charring the portion of hemp stalk at a temperature of greater than 1100° Celsius to create a char material; milling the char material to create a milled char; classifying the milled char with a classification system of less than 10 micron size to create a fraction of hemp char particles; collecting a desired fraction from the classification system of hemp char particles of less than 10 microns in size.

2. The process of claim 1 , 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 classification system includes a classification of 2 microns or less.

6. The process of claim 1 , where the desired fraction from the classification system are admixed with a polymer.

7. The process of claim 6 , wherein a material comprising the desired fraction and the polymer transmits an electrical charge with a resistance of less than 100Ω.

8. The process of claim 1 , 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.

9. A process for creating a masterbatch comprising a plurality of hemp char particles and a polymer comprising: carbonizing a portion of a hemp material in a furnace, said portion of hemp material comprising hemp fiber and hurd, said furnace being flushed with nitrogen and then heated to greater than 1100° C.; wherein the temperature greater than 1100° C. is held for at least 60 minutes; nitrogen flow is maintained 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 particles having average particle size of less than 2 microns to create char particles of less than 2 microns; combining the char particles having an average particle size of less than 2 microns with the polymer, wherein the ratio of char particles to polymer is between 10:90 and 50:50; and mixing the polymer and the char particles to form the masterbatch.

10. The method of claim 9 , wherein at least 90% of char particles are less than 2 microns in size.

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

12. The method of claim 9 , wherein the milling process is carried out using a ball mill.

13. The method of claim 9 , wherein the milling process is a wet milling process.

14. The method of claim 13 , wherein the wet milling process comprises use of a non-aqueous solvent.

15. The method of claim 9 , wherein the char particles having an average size of less than 2 microns are classified to remove particles of more than 2 microns in size.

16. A process of forming charred hemp particles of less than 2 micron in size, comprising: drying cut hemp stalk on a field for a period of less than 7 days, said hemp stalk comprising fiber and hurd; pyrolyzing the dried hemp stalk at 1100°-1500° Celsius to create a char; adding the char to a grinding vessel and grinding the char for a period of 1 to 16 hours; 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.

17. The process of claim 16 , wherein the grinding vessel is a steel vessel with steel grinding balls.

18. The process of claim 16 , wherein the grinding is dry grinding.

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

20. The process of claim 19 , wherein the wet grinding is performed for a first duration of between 1 and 16 hours and followed by a step of drying to create an agglomerated ground char and re-grinding the agglomerated ground char in a dry grinding process.

21. The process of claim 18 further comprising separating the material resulting from the 2-micron screen to particles smaller than 2 micron and particles larger than 2 microns and re-grinding the particles having a particle size greater than 2 microns.

Assignees

• Univ Jefferson

Inventors

• Sunderland Mark

Classifications

• C08K2201/005

  Additives being defined by their particle size in general · CPC title

• C08K3/04

  Carbon · CPC title

• C08K2201/011

  Nanostructured additives · CPC title

• C08K2201/001

  Conductive additives · CPC title

• C10B57/16

  Features of high-temperature carbonising processes · CPC title