Patent GB-1409277-A (GB)
Title: Production of reducing gas mixture
Inventor: MARION C P
IPC: C01B3/50
Filed: 1972-10-06
Abstract: 1409277 Production of reducing gas TEXACO DEVELOPMENT CORP 6 Oct 1972 [23 Dec 1971] 46174/72 Heading C5E A reducing gas mixture principally comprising carbon monoxide and hydrogen and containing a minor amount of particulate carbon is produced by (1) reacting a hydrocarbon fuel with an oxygen-containing gas by partial oxidation, in a free-flow reaction zone of a reducing gas generator at an autogenous temperature of 1500‹ to 3500‹ F. and a pressure of 1 to 350 atmospheres; (2) mixing, in a separate mixing zone, e.g. a separate vessel containing no obstruction to the free flow of the gas stream, effluent reducing gas leaving the free-flow reaction zone with an upgraded gas mixture recovered subsequently in the process to produce an improved reducing gas mixture containing less water vapour and particulate carbon than the effluent reducing gas; (3) introducing a portion of the improved reducing gas mixture into a gas-cooling and scrubbing zone located downstream from the mixing zone; and (4) withdrawing cooled and cleaned reducing gas from (3), compressing same to above the pressure of the effluent reducing gas from the reducing gas generator, and introducing the compressed reducing gas mixture into the mixing zone in (2) as the upgraded reducing gas mixture. Sufficient upgraded reducing gas mixture, e.g. 0À2 to 0À6 moles per mole of gas from step (1), may be mixed in step (2) to produce an improved reducing gas mixture at a predetermined temperature. The oxygen-containing gas may be air, oxygen-enriched air, i.e. air containing greater than 21 mole per cent oxygen, or substantially pure oxygen, i.e. containing greater than 95 mole per cent oxygen. Step (1) may be carried out in the presence of a temperature-modifying gas such as H 2 O, CO 2 , N 3 , e.g. as air, a cooled portion of reducing gas, cooled off-gas from an integrated ore-reduction zone, e.g. an iron-ore blast furnace, which may be fed with a portion of the improved reducing gas, an off-gas from another process, or a mixture thereof. The improved reducing gas has a temperature of 1800‹ to 2300‹ F. CO 2  and H 2 S may be removed from the reducing gas mixture leaving step (3). At least a portion of the off-gas from an ore reduction zone may be cleaned, cooled and purified, and then mixed with at least a portion of cooled and cleaned reducing gas from step (3) to produce the upgrade reducing gas mixture which is introduced into step (2), and a portion of the consequent improved reducing gas mixture leaving step (2) may be introduced into the ore-reduction zone to reduce metal oxides to metal, e.g. an iron-ore blast furnace to reduce iron oxides to iron. CO 2  and H 2 S may be removed from the orereduction zone off-gas, from the reducing gas mixture leaving step (3), or from both streams. The upgraded reducing gas mixture may have a temperature of 700‹ to 100‹ F. and a yield of particulate carbon of 1 to 8% by wt. (basis weight of carbon in feed). The gas stream from step (2) may be produced at a temperature of 1800‹ to 2300‹ F. The improved reducing gas mixture may be passed through a waste heat boiler for the production of steam before being introduced in the gas-cooling and scrubbing zone in step (3).