Feed injector for gasification and related method

1. A feed injector for use in a gasification apparatus comprising plural concentric tubes converging at an outlet tip of a radially outermost of said concentric tubes, at least one interior tube of said plural concentric tubes having a plurality of static, helically-twisted mixing elements fixed to an exterior surface thereof wherein said plurality of static, helically-twisted mixing elements include plural axially adjacent sets of two helically-twisted plates, extending axially along said at least one interior tube from adjacent said outlet tip at least to a fuel component inlet to said at least one interior tube.

2. The feed injector of claim 1 wherein said plural concentric tubes comprise three tubes including a center tube a radially intermediate tube and a radially outer tube, creating radially outer and radially intermediate annular passages and a center passage, said plurality of static, helically-twisted mixing elements fixed to the exterior surface of at least one of said radially intermediate and center tubes.

3. The feed injector of claim 2 wherein said plurality of static, helically-twisted mixing elements are fixed to the exterior surface of said center tube.

4. The feed injector of claim 2 and further comprising a primary oxygen/steam inlet to said radially outer passage; a secondary oxygen/steam inlet to said center passage; and a fuel/black water/steam inlet to said radially intermediate passages.

5. The feed injector of claim 1 wherein said adjacent sets of helically-twisted plates are arranged in left hand and right hand orientations, respectively.

6. The feed injector of claim 1 wherein each of said helically-twisted plates extends 180° about said exterior surface.

7. The feed injector of claim 1 wherein said static, helically-twisted mixing elements are welded to said exterior surface.

8. The feed injector of claim 1 wherein each of said helically-twisted plates is welded to said exterior surface.

9. The feed injector of claim 1 wherein said outlet tip is surrounded by a cooling coil.

10. A feed injector for use in a gasification apparatus in which streams of different fuel components are mixed, said feed injector comprising a plurality of concentrically arranged tubes including a radially outermost tube defining at least two annular passages and one center passage converging at an outlet tip of the radially outermost tube of the injector; and a plurality of static, helically-twisted mixing elements fixed on an internal one of said plurality of concentrically arranged tubes, said mixing elements arranged in alternating left and right hand pairs of such elements, and extending axially along said internal one of said plurality of concentrically arranged tubes from adjacent said outlet tip a distance more than one third a length dimension of the injector.

11. The feed injector of claim 10 wherein said plural concentric tubes comprises three tubes, including a center tube defining said center passage.

12. The feed injector of claim 11 wherein said plurality of static, helically-twisted mixing elements are fixed to the exterior surface of said center tube.

13. The feed injector of claim 12 wherein each of said helically-twisted plates extends 180° about said exterior surface.

14. The feed injector of claim 12 wherein said static, helically-twisted mixing elements are welded to said exterior surface.

15. The feed injector of claim 10 wherein said outlet tip is surrounded by a cooling coil.

16. A method of supplying fuel components to a combustion device through a feed injector comprising:

(a) providing a feed injector comprising plural concentric tubes including an outer tube, an intermediate tube and a center tube forming two annular passages and a single center passage converging at an outlet tip of said outer tube;

(b) fixing a plurality of static, helically-twisted mixing elements to at least a peripheral surface of said center tube, within a radially inner one of said two annular passages said helically-twisted mixing elements extending axially along said center tube from adjacent said outlet tip at least to a fuel component inlet to said center tube; and

(c) supplying fuel components through said two annular passages and said center passage for discharge through said outlet tip.

17. The method of claim 16 wherein said plurality of static, helically-twisted mixing elements include axially adjacent sets of two helically-twisted plates.

18. The method of claim 17 wherein said adjacent sets of helically-twisted plates are arranged in left hand and right hand orientations, respectively.

19. The method of claim 17 wherein each of said helically-twisted plates extends 180° about said exterior surface.