JFE No. 11 2006 4 p. 1 8 Short-Term Revamping Technology for Large Blast Furnace FUJITA Masao JFE TOKUDA Keiichiro JFE KOJIMA Hirotaka JFE 15 130 JFE 6 1998 62 JFE 5 2005 58 10 000 t 10 20 t 2 000 t Abstract: To revamp a blast furnace (BF) is required about every 15 years, and revamp duration by a conventional method is around 130 days. JFE Steel has developed a new revamping method, so called Large Block Ring Construction Method. By employing the method, the revamp duration was remarkably reduced to a half of a conventional one. A furnace body (10 000 t) was segmented into blocks of 10 t to 20 t weight during dismantling and installation in conventional method. Blocks by the Large Block Ring Constitution Method weigh over 2 000 t a piece. Consequently, the revamp duration of No. 6 BF at East Japan Works (Chiba) in 1998 was only 62 days, which was the world shortest record of revamp duration. The method was also successfully adopted to No. 5 BF at West Japan Works (Fukuyama) in 2005, and established a new world record of 58 days. 1. 130 15 JFE 5 58 2 2003 24 5 1998 6 1 3) 5 58 2. 110 m 10 000 t 2 000 t 3 4 Table 1 JFE 1998 Table 2 Fig. 1 5 JFE 58 6 62 1
Table 1 Comparison of conventional revamp and Large Block Ring Construction Method Revamp method Conventional revamp Large Block Ring Construction Method Height equal 30 FL building 110 m Total furnace weight: approximately 10 000 t Large block ring weight: 2 000 t Units weight: 10 20 t Construction method Unit number and weight 30 m Carry 10 20 t shell units into site and assemble at site 500 1 000 units 1 unit: 10 20 t Transport pre-assembled ring-blocks of 2 000 t into site 3 4 units 1 unit: 2 000 t Revamp duration 130 days 58 days Table 2 Revamp duration by large block ring method Chiba No. 6 BF Kurashiki No. 4 BF Kurashiki No. 2 BF Fukuyama No. 5 BF Revamp duration (day) 62 70 75 58 Revamp time (year) 1998 2001 2003 2005 Inner volume (m 3 ) 5 153 5 005 4 100 5 500 Slag Residual iron Furnace Coke 200 (1) Dismantling of old hearth Revamp duration (day) 150 100 50 1000 2000 3000 4000 5000 Large Block Ring Construction Method Chiba No.6 BF (1998) 62 days Fukuyama No.5 BF (2005) days Safety ceiling Heath brick Old mantel piece Inner volume (m 3 ) Fig. 1 Relation between inner volume and duration of revamps (2) Dismantle of old furnace 3. 3.1 1 500 / Fig. 2 1 30 New mantle (3) Assembling of new mantle Fig. 2 Outline of conventional method 2 2
20 3 500 40 4 40 1 4 130 3.2 1 500 1 000 1 10 20 130 2 3 3 4 4. 3 4 Rails 4.1 Fig. 3 1 2 (1) Dismantle of operating floor Lifting jacks 3 3 5 7 m 1 3 4.2 Moving Sliding platform platform 4 Fig. 4 1 Operating floor Transporting trucks Supporting columns Old mantel Mixed coke and slag Residual iron (2) Dismantle of hearth Transporting trucks (3) Dismantle of old furnace blocks Lifting Jacks Lifting Fig. 3 Outline of dismantling operation in large block ring method 4 3
Fig. 4 Mantle rest Top Shaft Bosh Hearth New furnace block (1) Pre-assembling of new furnace blocks Sliding platform Lifting jacks Sliding platform Rails Lifting jacks Lifting Moving platform Transporting trucks (2) Lifting up of new furnace block for transporting Supporting columns (3) Transporting of new furnace block Transporting trucks New furnace 5 000 t (4) Assembling and lifting up of new furnace Outline of assembling operation in large block ring method 4 5 000 t 5. 7 5.1 Fig. 5 Furnace shell Blast furnace Refractories Staves Hearth Bosh Shaft Top Lifting Connecting pipes (Outer side) Fig. 5 (Inner side) The section of furnace block Bricks laying after assembling Photo 1 Pre-assembling of new furnace blocks 1 000 2 000 t Photo 1 2 3 Lifting Photo 2 Furnace block 1 800 t 4 points supporting in lifting 4
4 Photo 2 1 2 5.2 5 000 t 1 000 t 5 000 t 3 3 m JBSD JFE Steel blast furnace structure design system 4) 1 2 3 30 JBSD Fig. 6 100 5 000 t 5.3 1/10 1 Fig. 7 Structure of blast furnace Reinforced frame 2 6 mm 5.4 Furnace 5 000 t Fig. 6 Model for framed structure analysis of blast furnace Subject for welding of outer side groove Impossible to fit backing plate at site Impossible to adjust linear misalignment without refractories cracks Furnace shell The site welding point (Outer side) Backing plate Refractories Staves Shell brace (Inner side) Fig. 7 The welding of one side groove 3 mm 5.1 5
Shell brace Bonding line at site maximum φ19 m 5.6 Assembling blocks in shop Linear misalignment in site bonding line 3 mm Fig. 8 5.5 mm 5.5 550t 1 2 Photo 3 Transporting mantle blocks 3 Preassembling blocks Bonding at site Linear misalignment in site bonding line 5.5 mm Fig. 8 Technology of precise bonding by welding between large block rings 2 000 t 2 000 t 4 650 t 4 30 mm 10 mm Fig. 9 2 000 t 5.7 6 15 000 m 2 4 2001 Residual iron block 550 t Lifting 2 000 t Lifting jacks Columns 650 t Dispersing load by large slabs 40 t/m 2 / 23 t/m 40 30 20 10 0 (day) 2 Spring back at unloading Ground settlement (mm) Preloading Unloading Actual loading Unloading Large slabs substituted for concrete foundation Ground settlement became less than 10 mm after preloading Photo 3 Hanging up large residual iron block Fig. 9 Technology of foundationless lifting and settlement trend at loading 6
Combination of rolling compacted ballast and steel plate /Relative settlement 30 mm φ1 500 mm 50 t Air Steel plate 25 mm Relative settlement 30 mm /Enhance applicable range of air caster with pin joint supporting frames Pin joint supporting frames Rolling compacted ballast Fig. 10 Technology of using foundationless air caster Chiba No.6 BF (1998) 15 000 m 2 Adopted usual BF Kurashiki No.4 BF (2001) 6 500 m 2 Operating floor Distance between blocks 15 m Movable lifting Operating floor Distance between blocks 3 m by using air caster Fixed lifting BF Dismantling yard Movable lifting Assembling yard of new furnace BF Dismantling yard Fixed lifting Assembling yard of new furnace Transporting truck length 30 m Fig. 11 Comparison of revamping area 6 500 m 2 1 6 30 m 15 m 4 3 m 0.35 MPa 35 t/m 2 a 25 mm b 30 mm Fig. 10 2 Fig. 11 2 6. 7
Conventional method Dismantling of hearth 20 (day) 130 30 Dismantling of large residual iron blocks Structuring of new furnace Dismantling Installation Test run and of old furnace of staves drying of furnace 40 60 80 100 120 Laying of bricks 20 25 15 30 10 Dismantling and preassembling large blocks Preassembling of all staves Large Block Ring Method 62 58 17 4 5 27 9 20 5 6 17 10 Chiba No.6 BF (1998) Fukuyama No.5 BF (2005) The shortest world record of revamp duration Fig. 12 Duration of revamps using conventional and new method 1 3 1 2 3 Fig. 12 1/6 4 5 000 m 3 1 Fujita, M.; Kojima, H.; Marushima, H.; Kawai, T. Iron and Steel Engineer. 1999-06, p. 38 42. 2 Fujita, M.; Kojima, H.; Marushima, H.; Matsumoto, T.; Yokogawa, A. La Revue de Metallurgie. 1999-03, p. 350 357. 3 vol. 32 no. 3 2000 p. 194 4 vol. 15 no. 3 1983 p. 193 200 7. JFE 1998 6 62 4 2 5 JFE 58 2006 2 22 8