Arrangement for separating coarse ash out of a flue gas stream

1. An arrangement for separating coarse ash out of a flue gas stream, comprising:

a flue gas channel that includes a widened channel portion, wherein said widened channel portion of said flue gas channel extends essentially vertically and adjoins a narrower, essentially horizontally extending flue gas channel portion via a connection zone, wherein deflection elements are disposed in said connection zone;

a catalytic converter for reducing an NO x level in said flue gas stream, wherein said catalytic converter is disposed in said widened channel portion of said flue gas channel, wherein a flow straightening means is disposed in said widened channel portion upstream of said catalytic converter; and

a separator sieve disposed in said widened channel portion of said flue gas channel downstream of said deflection elements and upstream of said flow straightening means, wherein said separator sieve extends essentially over an entire cross-section of said widened channel portion, wherein said separator sieve is provided with a plurality of openings for the passage of flue gas therethrough, and wherein each of said openings has a cross-section that is smaller than a cross-section of coarse ash particles that are to be separated out.

2. An arrangement according to claim 1 , wherein said separator sieve is embodied as a separator plate that is disposed in said widened channel portion at an angle of inclination of 10°<α<50° relative to a horizontal plane, and wherein at least one discharge opening for a withdrawal of coarse ash particles that are separated out is formed in an adjacent wall of said flue gas channel in the region of a lower end of said separator plate.

3. An arrangement according to claim 2 , wherein said at least one discharge opening is, connected with said flue gas channel downstream of said catalytic converter via an external bypass line.

4. An arrangement according to claim 2 , wherein said separator plate is comprised of portions that are folded or pleated in a zigzagged manner and that have fold lines that extend in the direction of incline.

5. An arrangement according to claim 4 , wherein between each two V-shaped, adjacent pleat or fold portions of said separator plate a groove is formed for a withdrawal of coarse ash particles that are separated out.

6. An arrangement according to claim 5 , wherein each of said grooves is connected to a discharge opening.

7. An arrangement according to claim 1 , wherein said separator sieve is a gable roof shaped sieve plate that is installed in said widened channel portion of said flue gas channel in such a way that two sieve plate sections extend downwardly in opposite directions from a ridge, and wherein respective lower edges of said sieve plate sections are in communication with at least one discharge opening.

8. An arrangement according to claim 1 , wherein said separator sieve is a bar screen, wherein said openings are gap-shaped and are delimited by parallel bars that have an approximately triangular cross-sectional shape and are interconnected, to form a rigid module, by tie bars that extend transverse to said parallel bars, and wherein said gap-shaped openings, when viewed in a direction of flow of flue gas therethrough, have a cross-sectional area that increases from an entry side to an exit side.

9. An arrangement according to claim 8 , wherein two respective bar screen modules are interconnected in an essentially V-shaped manner to form a base groove, and wherein said parallel bars that delimit said openings are disposed essentially at right angles to an orientation of said groove so as to be adapted to convey coarse ash particles in said groove.

10. An arrangement according to claim 9 , wherein said groove is inclined relative to a side wall of said widened channel portion of said flue gas channel.

11. An arrangement according to claim 8 , wherein said transversely extending tie bars are embodied as straightening ribs that are adapted to effect a straightening of the flue gas stream in a direction toward said catalytic converter.