Pulverized-Coal Firing of Aluminum-Melting Furnaces. Fourth Annual Technical Progress Report, July 1981-June 1982

摘要

The Alcoa/GE coal combustor is a two-stage, slagging cyclonic unit designed to direct fire an aluminum melting furnace at a rate of approximately 4.4 mm Btu/h (300 lb coal/h). The coal and an additive to trap sulfur compounds in the slag, is burned substoichiometrically in the first stage at 0.55 0 (55% of stoichiometric air) in the design case. Gaseous products leaving the first stage pass through a short analysis section and into the second stage, where sufficient air to complete combustion (total air = 10% excess) is injected. The hot (> 3000 exp 0 F) products of combustion pass directly into a melting furnace, which will be a 7-foot diameter ladle for the first combustor (Burner A), and to the stack. Shakedown operations continued during the fourth year of the contracted research and development program. Fifteen coal combustion tests were conducted, but all were terminated before steady-state conditions were attained because of mechanical and refractory problems. Lithium carbonate and calcium carbonate were used in the tests as fluxing/sulfur capture additives. Following relining with a brick more resistant to slag corrosion, shakedown operations will continue. (ERA citation 07:056092)