Tubular waterwall structure in a fluidized bed reaction chamber and a fluidized bed reaction chamber

1. A tubular waterwall structure in a fluidized bed reaction chamber, the tubular waterwall structure comprising:

multiple vertically extending tubular waterwalls defining the fluidized bed reaction chamber, the tubular waterwalls comprising horizontally adjacent first and second wall portions forming a corner structure and being constituted by vertical tubes interconnected by fins centrally attached to the tubes and having a first width,

wherein (i) the first wall portion has an outermost tube next to the corner structure, an upper portion defining an upper vertical plane in an upper level range and a lower portion defining a lower vertical plane in a lower level range, the lower portion having a refractory lining and each of the tubes of the first wall portion being bent in an intermediate level region between the upper level region and the lower level region so that the lower vertical plane is shifted outwards from the upper vertical plane, (ii) the second wall portion is vertical and has an outermost tube next to the corner, and (iii) the outermost tube of the second wall portion is in the lower level region connected to the outermost tube of the first wall portion by a planar lower beveled corner fin having a refractory lining and a width that is larger than the first width.

2. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein the width of the lower beveled corner fin is at least twice the first width.

3. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein the second wall portion does not have a refractory lining.

4. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein at least two outermost tubes of the second wall portion are coated with erosion resistant weld overlay.

5. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein the refractory lining of the lower portion of the first wall portion extends in horizontal direction at most to a vertical extension of the vertical plane of the upper portion.

6. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein the lower beveled corner fin is connected to an outer portion of the outermost tube of each of the first and second wall portions.

7. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 1 , wherein the outermost tube of the second wall portion is in the upper level region connected to the outermost tube of the first wall portion by a planar upper beveled corner fin having a width that is substantially equal to the first width.

8. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 7 , wherein the upper beveled corner fin forms an angle of about forty five degrees with each of the first and second wall portions.

9. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 7 , wherein the upper beveled corner fin is connected to an inner portion of the outermost tube of each of the first and second wall portions.

10. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 7 , wherein the plane of the lower beveled corner fin forms an angle from five degrees to fifteen degrees with the plane of the upper beveled corner fin.

11. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 7 , wherein the upper beveled corner fin comprises a planar vertically extending partial fin to the lower level region, the partial fin being attached to the outermost tube of the second wall portion and not attached to the outermost tube of the first wall portion.

12. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 11 , wherein the width of the vertically extending partial fin is substantially equal to the first width.

13. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 11 , wherein the width of the vertically extending partial fin is smaller than the first width.

14. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 13 , wherein the width of the vertically extending partial fin is less than 70% of the first width.

15. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 11 , wherein an outer surface of the refractory lining of the lower beveled corner fin abuts the outermost tube of the second wall portion at the vertically extending partial fin.

16. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 11 , wherein the refractory lining of the lower beveled corner fin extends in horizontal direction to a plane formed as a horizontal extension of the vertically extending partial fin.

17. A tubular waterwall structure in a fluidized bed reaction chamber according to claim 16 , wherein the refractory lining of the lower beveled corner fin is secured to the lower beveled corner fin by an anchor attached to the lower beveled corner fin.

18. A fluidized bed reaction chamber comprising:

a tubular waterwall structure, the tubular wall structure comprising:

multiple vertically extending tubular waterwalls defining the fluidized bed reaction chamber, the tubular waterwalls comprising horizontally adjacent first and second wall portions forming a corner structure and being constituted by vertical tubes interconnected by fins centrally attached to the tubes and having a first width,

wherein (i) the first wall portion has an outermost tube next to the corner structure, an upper portion defining an upper vertical plane in an upper level range and a lower portion defining a lower vertical plane in a lower level range, the lower portion having a refractory lining and each of the tubes of the first wall portion being bent in an intermediate level region between the upper level region and the lower level region so that the lower vertical plane is shifted outwards from the upper vertical plane, (ii) the second wall portion is vertical and has an outermost tube next to the corner, and (iii) the outermost tube of the second wall portion is in the lower level region connected to the outermost tube of the first wall portion by a planar lower beveled corner fin having a refractory lining and a width that is larger than the first width.

19. A fluidized bed reaction chamber according to claim 18 , wherein the width of the lower beveled corner fin is at least twice the first width.

20. A fluidized bed reaction chamber according to claim 18 , wherein the second wall portion does not have a refractory lining.

21. A fluidized bed reaction chamber according to claim 18 , wherein at least two outermost tubes of the second wall portion are coated with erosion resistant weld overlay.

22. A fluidized bed reaction chamber according to claim 18 , wherein the refractory lining of the lower portion of the first wall portion extends in horizontal direction at most to a vertical extension of the vertical plane of the upper portion.

23. A fluidized bed reaction chamber according to claim 18 , wherein the lower beveled corner fin is connected to an outer portion of the outermost tube of each of the first and second wall portions.

24. A fluidized bed reaction chamber according to claim 18 , wherein the outermost tube of the second wall portion is in the upper level region connected to the outermost tube of the first wall portion by a planar upper beveled corner fin having a width that is substantially equal to the first width.

25. A fluidized bed reaction chamber according to claim 24 , wherein the upper beveled corner fin forms an angle of about forty five degrees with each of the first and second wall portions.

26. A fluidized bed reaction chamber according to claim 24 , wherein the upper beveled corner fin is connected to an inner portion of the outermost tube of each of the first and second wall portions.

27. A fluidized bed reaction chamber according to claim 24 , wherein the plane of the lower beveled corner fin forms an angle from five degrees to fifteen degrees with the plane of the upper beveled corner fin.

28. A fluidized bed reaction chamber according to claim 24 , wherein the upper beveled corner fin comprises a planar vertically extending partial fin to the lower level region, the partial fin being attached to the outermost tube of the second wall portion and not attached to the outermost tube of the first wall portion.

29. A fluidized bed reaction chamber according to claim 28 , wherein the width of the vertically extending partial fin is substantially equal to the first width.

30. A fluidized bed reaction chamber according to claim 28 , wherein the width of the vertically extending partial fin is smaller than the first width.

31. A fluidized bed reaction chamber according to claim 30 , wherein the width of the vertically extending partial fin is less than 70% of the first width.

32. A fluidized bed reaction chamber according to claim 28 , wherein an outer surface of the refractory lining of the lower beveled corner fin abuts the outermost tube of the second wall portion at the vertically extending partial fin.

33. A fluidized bed reaction chamber according to claim 28 , wherein the refractory lining of the lower beveled corner fin extends in horizontal direction to a plane formed as a horizontal extension of the vertically extending partial fin.

34. A fluidized bed reaction chamber according to claim 33 , wherein the refractory lining of the lower beveled corner fin is secured to the lower beveled corner fin by an anchor attached to the lower beveled corner fin.