METHOD AND PLANT FOR PRODUCTION OF DIRECT REDUCED IRON (DRI) UTILIZING COKE OVEN GAS

• Main Authors: CONDOSTA, Michele, ZENDEJAS-MARTINEZ, Eugenio, BECERRA-NOVOA, Jorge-Octavio, MARTINIS, Alessandro
• Format: Patent
• Language: English; French; German
• Published: 29.10.2014
• Subjects: BLASTING; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; COMPOUNDS THEREOF; CRACKING HYDROCARBON OILS; DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS,IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KINDOF FURNACE; FUELS; FURNACES; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; INORGANIC CHEMISTRY; KILNS; LIGHTING; LUBRICANTS; MANUFACTURE OF IRON OR STEEL; MECHANICAL ENGINEERING; METALLURGY; METALLURGY OF IRON; MINERAL WAXES; NON-METALLIC ELEMENTS; OVENS; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVEHYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, ORGASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; RETORTS; TECHNICAL GASES CONTAINING CARBON MONOXIDE; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; WEAPONS

Direct reduction process and plant for producing DRI comprising a reduction reactor and at least one reducing gas heater typically comprising a convective heating section and a radiant heating section for raising the reducing gas temperature to a level adequate for iron oxides reduction to metallic iron, typically above 850° C., wherein the reducing gas fed to the reduction reactor comprises a stream of reducing gas recycled from the reduction reactor and a make-up stream of coke oven gas containing carbon compounds which may form carbon deposits in the heating path of said heater, namely BTX and other complex carbon compounds. The heater is provided with means for feeding oxidizing agents, for example steam, steam and air and/or oxygen at predetermined heating tubes successively for eliminating the carbon deposits which may form inside the heating tubes of said heater without interrupting the operation of the plant. The make-up stream of cold COG can be combined with the recycled gas at a point in the gas heating path of the heater where the tubes have a skin wall temperature of at least 700° C., or when the mixture of recycled gas and COG is at a temperature above 700° C. for minimizing clogging or fouling of heating equipment.