Enhanced energy recovery from the exhaust gases of basic oxygen furnaces through operation at pressure

Major changes required include: (1) enabling furnaces to operate under a pressure of three atmospheres; (2) tripling oxygen pressure; (3) increasing the temperature of compressed oxygen by heat exchange with the turbine exhaust flow; (4) confining the gases leaving the furnaces to ducts connected to a common duct through a one-way valve that would open only when furnace duct pressure exceeds that in the common duct; and (5) adding steam to reduce the temperature of the pressurized exhaust gas, which would then flow through a single-stage reduction turbine equipped with variable-angle nozzle vanes to maintain the pressure during flow variations (the added steam increases the turbine"s power output). The turbine exhaust gases would flow through rotary ceramic heat exchangers, incorporating a neutral-gas purge stage and heating pressurized oxygen for the lances. The gases would go to a waste heat boiler, a cooler, and probably a water wash before being ducted to gas mains for use in the plant. Such a process promises large benefits and considerable risks. More design studies and experimental trials should be undertaken. (Author abstract, modified)