Blast Furnace Operation with Natural Gas Injection at No. 2 Blast Furnace at East Japan Works (Keihin)

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1 JFE No p Blast Furnace Operation with Natural Gas Injection at No. 2 Blast Furnace at East Japan Works (Keihin) YAMAMOTO Koji JFE KASHIHARA Yusuke JFE TSUKIJI Hideaki JFE CO2 CO m 3 (2.56 t/d m 3 ) Abstract: To improve the productivity and reduce carbon dioxide emission in blast furnace operation, JFE Steel has considered introducing the blast furnace operation with natural gas (NG) injection. It is expected that the productivity in blast furnace is improved because of highly oxygen enriched operation and improvement of permeability. Reduction of carbon dioxide emission is also expected because of increase of hydrogenous reducing agent. NG injection adopted at No. 2 Blast Furnace at East Japan Works (Keihin), and the new world record of monthly productivity of the blast furnace (for inner volume: 5 m 3 ) is achieved (2.56 t/d m 3 ) CO2 CO2 CO CO2 CO2 55

2 2. 1) 1 CO H2 5 kg/t ) 1 TFT theoretical fl ame temperature TFT 2 5 kg/t TFT 2 4 TGT top gas temperature 12 3) TFT Oxygen enrichment (%) TFT ( C) Changes in productivity (t/d m 3 ) Fig. 2 Blast oxygen (Nm 3 /t) Theoretical flame temperature ( C) 1 Fig Base Base WP WP Input H (kg/t) NG CO2 Oil Oil NG : Pulverized coal WP: Waste plastics NG: Natural gas Effect of input H on operational conditions Base WP Oil 16 TFT TGT NG TGT ( C) : Pulverized coal WP: Waste plastics NG: Natural gas 2 Changes in operational conditions by various injectants Ash (mass%) 1 Table 1 Properties of various injectants Ultimate analysis (daf, mass%) C H O Calorific value (daf) (kcal/kg) Partial combustion heat (daf) (kcal/kg) Decomposition heat (daf) (kcal/kg) WP Oil NG : Pulverized coal WP: Waste plastics NG: Natural gas 3. 4) JFE No

3 2 Table 2 Experimental conditions A B C D E F G H I R (kg/t) WPR (kg/t) CH 4. R (kg/t) O 2 enr. (%) Blast 1 2 V tuy (m/s) 15 Ex. O Theoretical flame temperature (TFT): Constant R: Pulverized coal rate WPR: Waste plastics rate CH 4. R: Methane rate O 2 enr.: Enrichment Ex. O 2 : Excess O 2 ratio CH 4 Gas Waste plastics Pulverized coal Lance Air LPG O 2 Coke Coke packed bed Coke sampling Exhaust gas 1 4 mm Lance Raceway 1 mm (Width: 4 mm) Temperature measurement Gas sampling 3 Fig. 3 Experimental apparatus Combustion and gasification efficiency of solid injectant (%) 4 Fig % up 4% up Oxygen excess ratio : Pulverized coal WP: Waste plastics WP at CH 4 injection WP at CH 4 injection CH4 Effect of methane gas injection on combustion and gasifi cation effi ciency of solid injectants CH m/s TFT 6 N CH4 CH CH Fig. 5 WP at CH 4 injection WP Distance from tuyere nose (mm) WP at CH 4 injection WP 3 CO CO 2 CH4 CH4 CH4 Gas composition (%) H 2 O Distance from tuyere nose (mm) : Pulverized coal WP: Waste plastics CH4 Effect of methane gas injection on temperature and gas composition in raceway 57 JFE No

4 6 Fig. 6 Coke fine ratio ( 3 mm)(%) Oxygen excess ratio : Pulverized coal WP: Waste plastics CH4 CO2 6 3 mm CH4 5) H2O 4. 6) 4.1 WP CH 4 WP CH4 Effect of methane gas injection on coke fi ne ratio in raceway 7 5 mmφ 9 11 mm g mm 135 g 8 Flue gas Post burner Filter Gas analyzer Gas composition (%) Cyclone Heater Fig Load control Sample Gas pre-heater Gas mixing unit Experimental apparatus CO CO 2 H Temperature Load Time (min) 8 Fig. 8 Experimental conditions 9 7).3.1 Load (kg/cm 2 ) N 2 CO CO 2 H 2 JFE No

5 Fig. 9 Shrinkage (%) Reduction degree (%) H 2 : vol% H 2 : 5 vol% H 2 : vol% Pressure drop (kpa) Effect of gas composition on shrinkage and reduction degree H 2 : vol% H 2 : 5 vol% 2. H 2 : vol% Fig. 1 5 Effect of gas composition on pressure drop Natural gas Fig. 11 JFE Steel ) Blast furnace Flow diagram of natural gas injection plant kg/t TFT KU KL 2.34 t/d m t/d m Furnace top S7 S6 S5 S4 Tuyere S3 S2 S1 12 Fig. 12 K L K U Natural gas off Natural gas on (2 5 kg/t) Effect of natural gas injection on permeability 59 JFE No

6 1 2.8 Mar. 24 Blow-in Dec. 24 Natural gas operation May 26 High productivity operation 2.6 Productivity (t/d m 3 ) CO Apr. 24 Apr. 25 Apr. 26 Apr Fig. 13 Operation trends of No. 2 Blast Furnace at East Japan Works (Keihin) t/d m t/d m 3 5 m t/d m t/d m 3 5 m 3 1 CAMP-ISIJ 25 vol. 18 p Oscar Lingiardi et. al. Proc. Ironmaking Conf. 1999, p CAMP-ISIJ 24 vol. 17 p. 6 4 CAMP-ISIJ 26 vol. 19 p vol. 85 p CAMP-ISIJ 26 vol. 19 p vol. 66 s699 8 CAMP-ISIJ 27 vol. 2 p JFE No