CHEMICAL RECOVERY BOILER

A chemical recovery boiler (100)， including a furnace (1)， comprising a front wall (2)， a back wall (3)， and the back wall (3) comprising a nose arch (4). The boiler further comprises at least one superheater (5) arranged in upper part of the furnace (1)， and a screen pipe system (6)， comprising an obliquely arranged screen pipe section (7) positioned before/under the at least one super-heater (5) in the furnace (1). The obliquely arranged screen pipe section (7) comprises screen pipes (8) ascending (i) either from the front wall (2) to the back wall (3)， and arranged to turn back in a turn (13) from the back wall (3) and extend obliquely upwards from the back wall (3)， or (ii) from the back wall (3) to the front wall (2)， and arranged to turn back in a turn (13) from the front wall (2) and extend obliquely upwards from the front wall (2). The screen pipe system (6) further comprises a vertically arranged screen pipe section (9) extending from the obliquely arranged screen pipe section (7). The screen pipes (8) of the vertically arranged screen pipe section (9) are arranged to extend parallel with the at least one superheater (5) in upper part of the furnace (1).