Methods of generating energy from cellulosic biofuel waste

Patent metadata

Field	Value
Publication number	US-10415825-B2
Application number	US-201715601230-A
Country	US
Kind code	B2
Filing date	May 22, 2017
Priority date	Jun 7, 2016
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

Energy is generated from cellulosic biofuel waste streams, specifically a lignin filter cake and a waste syrup, by combusting these waste products in a fluidized bed combustor under specified conditions. The heat and steam generated can be used to generate electricity and/or in cellulosic biofuel production processes.

First claim

The invention claimed is:

1. A method for generating energy from cellulosic biofuel waste, comprising:
feeding a lignin filter cake to a fluidized bed;
feeding a waste syrup to one or more discrete locations in the fluidized bed; and
combusting the lignin filter cake and the waste syrup to generate energy;
wherein the lignin filter cake does not contact the waste syrup.

2. The method of claim 1 , wherein the lignin filter cake has a moisture content of about 35% to about 60%.

3. The method of claim 1 , wherein the waste syrup has a moisture content of about 30% to about 50%.

4. The method of claim 1 , wherein the waste syrup is fed as a stream directed at a plan area of the fluidized bed.

5. The method of claim 4 , wherein the waste syrup is fed as a stream directed at a center of a plan area of the fluidized bed.

6. The method of claim 4 , wherein the plan area is rectangular.

7. The method of claim 1 , wherein the waste syrup is fed to the fluidized bed at a temperature of about 100° F. to about 200° F.

8. The method of claim 1 , wherein the fluidized bed has a bed temperature of about 1200° F. to about 1500° F.

9. The method of claim 1 , wherein flue gas generated by the fluidized bed is recirculated back to the fluidized bed.

10. The method of claim 1 , wherein a furnace wall temperature is kept at about 1000° F. or less.

11. The method of claim 1 , further comprising introducing an additive to the waste syrup to reduce agglomeration.

12. The method of claim 1 , wherein the fluidized bed has a bed drain rate of about 2.5% to about 10%.

13. The method of claim 12 , wherein the fluidized bed drain rate is adjusted based on characteristics of fluctuations in primary zone differential pressure.

14. The method of claim 1 , wherein the lignin filter cake and the waste syrup are fed to the fluidized bed using a dual-phase fuel feeder.

15. The method of claim 14 , wherein the waste syrup is fed below the lignin filter cake.

16. The method of claim 14 , wherein the waste syrup is fed above the lignin filter cake.

17. The method of claim 14 , wherein the waste syrup is fed adjacent to a filter cake feeder, or wherein the waste syrup is fed between filter cake feeders as a separate stream.

18. The method of claim 1 , wherein an alkali species plus phosphorus concentration within the fluidized bed is less than 5% Na+K+P.

19. The method of claim 1 , wherein water in water-cooled walls surrounding the fluidized bed flows in a closed-loop recirculation path.

20. The method of claim 1 , wherein the waste syrup is combusted in the freeboard of the fluidized bed.

Assignees

• Babcock & Wilcox Co

Inventors

• Desellem James F
• Flynn Thomas J
• Heil Karl M
• Wells Eric L

Classifications

• Y02E20/12

  Heat utilisation in combustion or incineration of waste · CPC title

• F23G2900/50007

  Co-combustion of two or more kinds of waste, separately fed into the furnace · CPC title

• F23G2209/26

  Biowaste · CPC title

• F23G2209/12

  Sludge, slurries or mixtures of liquids · CPC title

• F23C2206/102

  Control of recirculation rate · CPC title