GB728007A - Improvements in or relating to a process and apparatus for the conversion of pig iron into steel - Google Patents

Abstract

728,007. Refining steel. WARNANT, R. E. Nov. 24, 1952 [Nov. 23, 1951; Oct. 29, 1952], No. 29664/52. Class 72. A process for converting pig iron into steel low in nitrogen comprises blowing the steel with a mixture of oxygen and superheated steam in which the temperature of the blowing mixture is controlled by adding to at least one of the constituents of the mixture the hot products of combustion of a fuel burnt under pressure to maintain the superheat of the steam in the mixture at the required degree. As shown, steam is introduced through a pipe 2 into a heating chamber 5 into which are also led the products of combustion of a fuel, e.g. methane, coke oven gas, lighting gas or water gas or mixtures of these gases, burned in an antechamber 7. Oxygen from a pipe 13 is mixed with the mixture coming from the heating chamber 5 and the mixture of oxygen, superheated steam and products of combustion is supplied to a converter 4 through a pipe 17 having a blowing valve 18. A proportional regulator 21 controlled by a thermo regulator 23 actuates flow meters 19 and 20 controlling steam and fuel from a pipe 8 respectively entering the heating chamber 5, the oxygen for combustion of the fuel being controlled by a flow meter 26. A thermo regulator 32 on the outlet side of the chamber 5 operates a motorized valve 31 leading to an escape valve 29 in such manner that the valve 31 shuts as the temperature of the mixture exceeds, and opens as the temperature is lower than, the degree of superheat required. In a modification, Fig. 2 (not shown), oxygen may be added to the mixture in the heating chamber 5 and in a further modification the burner may be supplied with air which may be enriched with oxygen and the escape valve 29 may be under manual control, Fig. 4 (not shown).