IN-BED HEAT TRANSFER TUBE FOR FLUIDIZED BED BOILER, AND FLUIDIZED BED BOILER

摘要

Provided is an in-bed heat transfer tube for a fluidized bed boiler, which has a sufficient heat transfer effect, and with which molten salt corrosion can be suppressed, thereby limiting the reduction in the thickness of the tube and providing excellent durability. This in-bed heat transfer tube (5) is configured from: an inner tube (6), in the interior of which a fluid (water, saturated water, steam, a binary fluid, or the like) flows; inner tube fins (37) provided on the outer circumference of the inner tube (6) as a securing part; and a protector (8), which is provided on the outer circumferential side of the inner tube (6) so as to form a 0.25-0.75 mm gap (7) therebetween, and which protects the inner tube (6). A pair of the inner tube fins (37) is affixed to the outer circumferential surface of the inner tube (6) by welding, and the protector (8) is affixed to the inner tube fins (37) by welding in the same manner. Multiple slits (81) with a width of 0.5 mm are formed in the protector (8) at 50 mm intervals.