Patent ID: 7645319
Filing Date: 2010-01-12
Classification: C21B,F25J

Abstract:
1. A method for revamping a combined system consisting of a blast furnace supplied with oxidizing fluid issuing at least partially from an air gas separation unit (ASU), wherein more than 50% of the flow from a blower feeding the blast furnace before revamping is injected into a cryogenic air gas separation unit in order to produce oxygen with a purity above 90% by volume of O 2 , a post-revamping blast furnace feed fluid consisting of pure oxygen or oxygen diluted with air produced by the cryogenic separation unit, said oxygen of purity above 90% by volume of O 2 being fed to the blast furnace in order to obtain over 90% by volume of O 2 in the post-revamping blast furnace feed fluid, the blower air flow rate and/or pressure of the air issuing from the blower being controlled by a controller which measures this flow rate and/or pressure at the inlet and/or outlet of the air cleaning stage, placed upstream of the separation unit, in order to control the flow rate or pressure of the air issuing from the blower.