Evolution of the Slag-Tap Furnace at the Charles R. Huntley Station of the Buffalo General Electric Co.

Abstract

Abstract The handling of low-fusion-ash coals at high ratings and with high efficiencies is one of the stiffest problems ever presented to a furnace designer. This paper tells how in their attempt to design a furnace that would burn any coal offered on the Buffalo market the engineers developed the slag-tap furnace for burning powdered coal, after ten years’ experience in driving stoker-fired boilers at 300 to 400 per cent of rating. Because of the greater freedom in selecting coals for a powdered-coal-fired furnace and on account of the greater capacities that could be obtained from the boilers by that method of firing, also because boilers so fired could be made to respond more readily to sudden changes in load incident to peak-load standby plant operation than by any other method of coal firing, powdered-coal firing was chosen for the 60,000-kw. 1926 extension to Charles R. Huntley Station. To obtain data for designing the furnaces under four cross-drum boilers which were purchased to deliver 200,000 lb. of steam per hour, an experimental furnace was installed under one of them. Maximum ratings were in mind and 275,000 lb. per hr. evaporation was obtained. The paper shows how these experiments, on a furnace designed to remove the ash in the dry form, led to the development of the slag-tap furnaces for the 1926 extension and again for the 1928 extension, where the ratings were increased still further. The performance of the slag-tap furnace has exceeded the expectation of its designers. Some of its advantages from both the design and operating standpoint are here enumerated: It requires a minimum of building volume It will burn efficiently and at high ratings an unusually wide variety of coals It produces quick ignition of the fuel It prevents infiltration of air into the bottom of the furnace It requires a minimum of ash-handling labor, and The ash handling is remarkably free from dust and dirt.