US 5,830,259 AGranted

Preventing skull accumulation on a steelmaking lance

AssigneeLTV Steel Company, Inc.

InventorsChung S. Kim, Ken M. Goodson

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Abstract

A self-cleaning lance includes a lance body elongated along a longitudinal axis and having an upper end portion and a lower end portion, the lower end portion being spaced apart from the upper end portion along the longitudinal axis. One or more main nozzles are located proximal to the lower end portion and are adapted to release an oxygen-containing gas. One or more deskulling nozzles are spaced upwardly from the lower end portion and are adapted to release a deskulling gas. The lance body has a first portion that extends axially from the deskulling nozzles to the main nozzles and a second portion above the deskulling nozzles. The first portion has a smaller outer perimeter than the outer perimeter of the second portion. Each of the deskulling nozzles extends by an angle of not greater than 25 degrees with respect to the longitudinal axis.

Claims30

Dependent claims

A self-cleaning steelmaking lance that prevents accumulation of skull on said lance when said lance is used in a steelmaking vessel, said lance comprising:

a lance body elongated along a longitudinal axis and having an upper end portion and a lower end portion,
at least one main nozzle each located proximal to the lower end portion and extending along a main nozzle axis, the at least one said main nozzle being adapted to release an oxygen-containing gas,
at least one upper deskulling nozzle each extending along an upper deskulling nozzle axis and spaced upwardly from the at least one said main nozzle along the longitudinal axis, said lance body having a first portion that extends axially between the at least one said upper deskulling nozzle and the at least one said main nozzle and said lance body having a second portion above the at least one said upper deskulling nozzle said first portion having a smaller outer perimeter than the outer perimeter of said second portion, and
at least one lower deskulling nozzle each disposed below the at least one said upper deskulling nozzle and extending along a lower deskulling nozzle axis, said lance body further including at least one intermediate portion disposed between the at least one said upper deskulling nozzle and the at least one said lower deskulling nozzle, said intermediate portion having an outer perimeter that is greater than the first portion outer perimeter and less than the second portion outer perimeter,
wherein said upper and lower deskulling nozzles extend at an angle not greater than 25 degrees with respect to the longitudinal axis,
wherein a transition between the first portion outer perimeter and the intermediate portion outer perimeter forms a first shoulder and a transition between the intermediate portion outer perimeter and the second portion outer perimeter forms a second shoulder and the at least one said upper deskulling nozzle communicates with said second shoulder and the at least one said lower deskulling nozzle communicates with said first shoulder.

3 more elements

A method of operating a steelmaking lance in a self-cleaning manner, comprising the steps of

positioning the lance in a steelmaking vessel,
flowing a deskulling gas to at least one deskulling nozzle spaced upwardly from at least one main nozzle along a longitudinal axis of said lance, each said main nozzle being disposed near a lower end portion of said lance and extending along a main nozzle axis and each said deskulling nozzle extending along a deskulling nozzle axis, said lance body having a first portion that extends axially between the at least one said deskulling nozzle and the at least one said main nozzle and said lance body having a second portion above the at least one said deskulling nozzle, said first portion having a smaller outer perimeter than an outer perimeter of said second portion,
directing said deskulling gas from the at least one said deskulling nozzle along the deskulling nozzle axis at an angle not greater than 25 degrees with respect to the longitudinal axis, and
regulating flow of said deskulling gas to be at a flow rate that is not greater than about 1500 standard cubic feet per minute during an entire steelmaking process to prevent accumulation of substantially all skull on said lance and to prevent excessive heating of said lance.

1 more element

Dependencies are inferred from the claim text.