Process for ammoniating cellulosic materials

• US 6,548,659 B1
• Filed: 03/30/2001
• Issued: 04/15/2003
• Est. Priority Date: 01/31/2001
• Status: Active Grant

• Current Assignee: Board of Supervisors of Louisiana State University Agricultural & Mechanical College (Louisiana State University System)
• Original Assignee: Board of Supervisors of Louisiana State University Agricultural & Mechanical College (Louisiana State University System)
• Inventors: Breitenbeck, Gary, Kember, Keith
• Primary Examiner(s): Wilson, James O.
• Assistant Examiner(s): Young, Josephine
• Application Number:
  US09/823,206
• Time in Patent Office: 746 Days
• Field of Search: 426/69, 426/635, 426/807, 536/18.7, 536/30, 536/55, 536/55.1, 536/55.3, 536/56, 536/123.1, 162/91, 162/96
• US Class Current: 536/30
• CPC Class Codes: C08B 1/00 Preparatory treatment of cellulose for making derivatives thereof , e.g. pre-treatment, pre-soaking, activation
• CPC Class Codes: C08B 15/06 containing nitrogen , e.g. carbamates
• CPC Class Codes: C08H 8/00 Macromolecular compounds derived from lignocellulosic materials pretreatment thereof B27N
• CPC Class Codes: C08L 1/02 Cellulose; Modified cellulose
• CPC Class Codes: C08L 97/02 Lignocellulosic material, e.g. wood, straw or bagasse manufacture of articles made from lignocellulosic material by dry processes B27N
• CPC Class Codes: Y10S 426/807 Poultry or ruminant feed

Abstract

Process for enriching the organic nitrogen content of commercial scale quantities of cellulosic materials which includes the steps of: a) placing substantially dry or unwetted cellulosic material in a pressurizable reactor; b) injecting an ammonia or ammonia-forming nitrogen solution into the reactor until the cellulosic material is approximately submerged; c) setting the temperature in the reactor to maintain a liquid temperature between about 80 and 200° C.; d) pressurizing the reactor to at least 750 psi; e) maintaining the temperature and pressure in the reactor for a period of time sufficient for the organically bound nitrogen content of the cellulosic material to exceed about 1.5%; and f) drying the cellulosic material to a moisture content sufficiently low to arrest microbial activity.

Claims

1. A process for nitrogen enriching a cellulosic material comprising the steps of:

a) providing a cellulosic material;

b) moistening the cellulosic material to over approximately 50% of its saturated moisture content;

c) placing said cellulosic material in a reactor vessel;

d) pressurizing said reactor to a pressure of less than about 200 psi;

e) injecting into said reactor an amount of a nitrogen based compound equal to about 2% to 8% of the dry weight of said cellulosic material;

f) allowing an exothermic reaction to occur until the temperature of said cellulosic material stabilizes;

g) increasing pressure in said reactor vessel to at least about 700 psi while maintaining a temperature in said reactor vessel under about 200°

C. for a period of time sufficient for the organically bound nitrogen content of said cellulosic material to exceed about 1.5% N on a dry weight basis; and

h) drying said cellulosic material to a moisture content sufficiently low to arrest microbial activity.

2. The process according to claim 1, wherein said cellulosic material provided is bagasse having a total nitrogen content of about 0.5%.

3. The process according to claim 1, wherein said moisture content of said cellulosic material equivalent to about 4 grams of water for each grams of dry cellulosic material.

4. The process according to claim 1, wherein said reactor vessel is pre-heated to about 100°

C.

5. The process according to claim 1, wherein said step of allowing said exothermic reaction is continued until said cellulosic material is approximately 2°

C. below a maximum temperature obtained during said exothermic reaction.

6. The process according to claim 1, wherein said reactor vessel is pressurized to at least 750 psi.

7. The process according to claim 6, wherein the reactor vessel is pressurized to about 1000 psi.

8. The process according to claim 7, wherein the reactor vessel is maintained at a temperature of between about 100°

C. and about 110°

C. for about 90 minutes.

9. The process according to claim 1, wherein the amount of nitrogen based compound injected is equal to at least about 4% of the dry weight of said cellulosic material.

10. The process according to claim 1, wherein the ammonia or ammonia-forming nitrogen includes ammonia or ammonium hydroxide.

11. The process according to claim 1, wherein said cellulosic material is dried to a moisture content of about 12% on a dry weight basis in order to arrest microbial activity.

12. The process according to step 1, wherein step (g) further includes maintaining said pressure and temperature for a period of time sufficient for the organically bound nitrogen content of said cellulosic material to reach at least about 2.75% N on a dry weight basis.

13. A process for nitrogen enriching a cellulosic material comprising the steps of:

a) placing substantially dry or unwetted cellulosic material in a pressurizable reactor;

b) providing an ammonium hydroxide solution within said reactor to a level which approximately submerges said cellulosic material;

c) setting the temperature in said reactor to maintain a liquid temperature between about 80 and 200°

C.;

d) pressurizing the reactor to at least 750 psi;

e) maintaining said temperature and pressure in said reactor for a period of time sufficient for the organically bound nitrogen content of said cellulosic material to exceed about 1.5%;

f) drying said cellulosic material to a moisture content sufficiently low to arrest microbial activity.

14. The process according to claim 13, wherein the ammonium hydroxide solution may range from 0.5 to 5.0 M solution.

15. The process according to claim 13, wherein said step of maintaining said temperature and pressure continues for a period of about 90 minutes.

16. A process for nitrogen enriching a cellulosic material comprising the steps of:

a) placing substantially dry cellulosic material in a pressurizable reactor;

b) providing an ammonium hydroxide solution within said reactor to a level which approximately submerges said cellulosic material;

c) setting the temperature in said reactor to maintain a liquid temperature above about 80°

C.;

d) pressurizing said reactor to at least 750 psi; and

e) maintaining said temperature and pressure in said reactor for a period of time sufficient for the organically bound nitrogen content of said cellulosic material to exceed about 1.5%.