Method apparatus for increasing blast gas temperature in a shaft furnace

Claim 1

In a method of reducing ores in a shaft furnace which includes a tuyere and is operable with a first source of fuel fed into the upper part of the furnace, a source of blast gas, and means for flowing said gas through said tuyere into said furnace, the improvement in combination therewith comprising the steps: providing a source of additional fuel comprising a liquid hydrocarbon for increasing the blast gas temperature, providing a plasma burner, dividing said blast gas into first and remaining portions, flowing said first portion of said blast gas into said burner, heating said first portion of said blast gas in said burner by generating therewith a plasma, flowing said heated portion of said blast gas through a central passage in a nozzle which discharges into said tuyere, flowing said additional liquid fuel into said nozzle and discharging same in an annular flow generally surrounding said central passage, and thereby mixing said liquid fuel and said heated portion of the blast gas, and heating and gasifying said fuel which forms with said heated portion of the blast gas a first mixture, intermixing in said tuyere said first mixture and said remaining portion of said blast gas, thus forming a second mixture, and flowing said second mixture into said furnace at said tuyere level, where said additional fuel is substantially completely burned.