Patent ID: 8992823
Filing Date: 2015-03-31
Classification: C21B,Y02P

Abstract:
1. A method of operating regenerative heaters, in particular hot-blast stoves, in a blast furnace plant, said plant comprising: a blast furnace, a gas separation unit configured for separating top gas from said blast furnace into a stream of CO-enriched process gas and a stream of CO-depleted tail gas; at least three regenerative heaters, each having internal heat storage elements, a cold blast inlet for receiving CO-enriched process gas from said gas separation unit and a hot blast outlet for feeding CO-enriched process gas to said blast furnace; said method comprising cyclically operating said regenerative heaters on blast and on gas, said cyclic operation including while operating a regenerative heater on gas, producing hot flue gas with a burner and causing said hot flue gas to flow through said regenerative heater so as to heat said heat storage elements; and while operating a regenerative heater on blast, blowing CO-enriched process gas through said regenerative heater for the CO-enriched process gas to take up heat from said heat storage elements; said method further comprising during a changeover of a regenerative heater from on-blast to on-gas operation, purging said regenerative heater from CO-enriched process gas with flue gas collected after having passed through at least one of said regenerative heaters.