GB942262A - Waste-heat boiler with slag-catching device - Google Patents

Abstract

942,262. Waste heat steam boilers; metallurgical converter chimneys and hoods. WAAGNER-BIRO A.G. May 2, 1960, No. 15399/60. Headings F4A, F4B, F4J and F4X. A waste-heat boiler for utilizing the heat of the blow gases from a Bessemer converter 8 operating on the basic process is disposed in a flue 3, the upper part of which serving to convey the gases to atmosphere being closed by a damper 10. The flue is divided by a partition wall into an up-pass constituting a radiation chamber 1 which is lined with contacting generating tubes and a downpass locating convectively heated surfaces 2. From the bottom of the downpass which contains a wet filter 12, the gases ascend in a third pass containing further wet filters 15 to an exhaust fan which delivers them into a stack 11. Water from the filters collects in funnels 5 and flows from the funnels to dust recovery plant, not shown. To prevent the boiler heating surfaces from being fouled by slag entrained in the blow gases a screen 4 of tubes is arranged across the boiler inlet so that the gases impinge thereon. The screen consists of several rows of tubes arranged in staggered formation, each tube consisting, as shown in Fig. 6, of an outer tube 13 within which is coaxially disposed an inner tube 14 extending almost to the closed bottom of the outer tube. Water flows down the inner tube whilst steam and/or water discharges from the outer tube, the screen tubes being included in the circulatory flow of the boiler. To dislodge slag accumulating on the screen the tubes are suspended so that they can swing freely, the gas flow causing them to collide so that deposited slag is dislodged and falls on to a watercooled travelling grate 7 whereon it is quenched and carried to slag-processing plant. The tubes can also be swung mechanically or vibrated for example by a pulsating supply of water thereto, to cause the slag to be dislodged.