NON-DESTRUCTIVE BLAST FURNACE WALL TESTING

by Michael J. Vermeer

Dr. Yulian Kin, Advisor

Eric S. Roades Krasimir Zahariev

Bernard W. Parsons II

Friday, December 8, 2006

Background

•  Blast Furnace is a tall vertical shaft used for refining iron ore into molten iron –  Refractory brick forms the interior lining which comes into contact

with the iron and other refining materials •  As iron is refined in the blast furnace, erosion occurs on this

refractory lining •  Improved technology to monitor the erosion in this lining

will significantly increase profitability and productivity of blast furnace operation

•  A project to develop this technology is made possible especially by the 21st Century Science and Technology Fund of Indiana

Project Purpose and Description

•  The focus of this project is to investigate the use of acoustic measurement techniques to measure the thickness changes in a blast furnace wall.

•  This was done through several phases of studies performed to validate different aspects to the acoustic method –  In the first part of the project, it was verified that the concept

worked to determine depth in a regular, undamaged brick –  Next it was used to detect shifting depths, as damage was

applied to a brick in laboratory conditions –  A study was also performed to investigate the effect of the steel

lining on the outside of the furnace –  Finally, the method was applied to an actual blast furnace to

monitor the wall thickness over time

Project Timeline

TASKS Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1. Perform Modal Analysis 2. Build Prototypes and

Conduct Measurements 3. Determine Material

Properties 4. Process Results 5. Simulate and Assess Damage 6. Study Effect of Steel Lining

on Measurements 7. Apply Acoustic Method to

Field Measurements 8. Make Recommendations 9. Document and Report

Findings

Derivation of Formula

where, v = velocity λ = wavelength f = compressive frequency

node

antinode

dfv

dfv

××=

×=

×=

2

2

λλ

Acoustic Method (IRAS)

•  The figure below shows the test setup for all of the experimental measurements taken –  Impactor strikes block (or wall) near the point of measurement –  Laser Vibrometer measures displacement vs. time –  Computer performs Fast Fourier Transform (FFT) on displacement

signal, from which shifts in compressive natural frequency can be determined

Damage Study Depth Measured Using Vibrometer and

Workbench vs. Actual Depth

0.150

0.160

0.170

0.180

0.190

0.200

1 2 3 4

Experiment Number

Dep

th (m

)

L-actual (m)L-vibrometer (m)L-ansys (m)

Plated Study

Comparison of Major Modes Between Plated and Unplated Blocks

0.01000.02000.03000.04000.05000.06000.07000.08000.09000.0

10000.0

1 2 3 4 5 6 7 8

Mode #

Mod

al F

requ

ency

(Hz) Unplated modes (Hz)

Plated modes (Hz)

Application to Blast Furnace Wall

Ring B

Ring A

Blast Furnace Application – Method A

•  Uses the equation derived above to determine thickness

•  Can directly evaluate thickness of wall

•  Does not require knowledge of previous wall thickness

•  Requires knowledge of material properties

•  Needs validation data

0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.40

2

4

6

8

10

12

14

X: 0.785Y: 12.56

Frequency (kHz)

Mag

nitu

de

Frequency Comparison - Ring A, Position #1

X: 1.04Y: 4.649

Apr06Jul06

Blast Furnace Application – Method A Results

April and July Furnace Profiles - Ring A

0

1

2

3

4

51

2

3

4

5

6

7

8

910

11

12

13

14

15

16

17

Outer Radius April Radius July Radius

April and July Furnace Profiles - Ring B

0

1

2

3

4

51

2

3

4

5

6

7

8

910

11

12

13

14

15

16

17

Outer Radius April Radius July Radius

July ‘06 Radius April ‘06 Radius

Blast Furnace Application – Method B

•  Based on comparing the shift in Frequency to the shift in Depth

•  Does not require specific knowledge of material properties

•  Requires an accurate baseline inner profile

•  Needs validation data

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 30

0.5

1

1.5

2

2.5

Frequency (kHz)

Mag

nitu

de

Frequency Comparison - Ring A, Position #1

Aug05Oct05Apr06Jul06

Blast Furnace Application – Method B Results

Blast Furnace Depth Measurements - Ring A

00.5

11.5

22.5

33.5

44.5

51

2

3

4

5

6

7

8

910

11

12

13

14

15

16

17

Outer Inner Depth wrt APR Depth wrt AUG

Blast Furnace Depth Measurements - Ring B

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

51

2

3

4

5

6

7

8

910

11

12

13

14

15

16

17

Outer Inner Depth wrt APR Depth wrt AUG

July ‘06 wrt April ‘06 July ‘06 wrt Aug ‘05

Blast Furnace Application – Method B Profile

Location 6 Vertical Profile

0

0.5

1

1.5

2

2.5

3 3.5 4 4.5 5 5.5

Radius from Furnace Center (m)

Hei

ght a

bove

pla

tfor

m (m

)

Outer WallJUL w rt APRJUL w rt AUGInner Wall

Location 16 Vertical Profile

0

0.5

1

1.5

2

2.5

3 3.5 4 4.5 5 5.5

Radius from Furnace Center (m)

Hei

ght a

bove

pla

tfor

m (m

)

Outer WallJUL w rt APRJUL w rt AUGInner Wall

July ’06 wrt April ‘06 July ’06 wrt Aug ‘05

Recommendations

•  This project displays promising results •  Further validation is required •  Further analysis should be made of Rings A and B at BF #3

–  Establish baseline wall thickness data –  Install thermocouples so that CFD analysis can be performed for

comparison •  Obtain and perform analysis of precise materials that

compose the wall at measurement locations of BF #3

Conclusions

•  This project was devoted to researching the application of the acoustic method for wall thickness monitoring

•  Though further validation is required, results strongly indicate that the wall thickness of a blast furnace can be monitored using acoustics

Acknowledgements

Dr. Yulian Kin Eric S. Roades

Krasimir Zahariev Bernard W. Parsons II

Pete Peters & CMET Dept. Rick Rickerson & METS Dept.

21st Century Science and Technology Fund of Indiana Mittal Steel

Et. Al.