This study shows how vibration data can be collected and analyzed to perform predictive diagnostics in the steelmaking process. The research was done in an effort to move away from the dangerous process of going inside blast furnaces to measure wall thickness.

1. 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

2. 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

3. 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

4. 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

5. Derivation of Formula
where,
v = velocity
λ = wavelength
f = compressive frequency
node
antinode
dfv
d
fv
××=
×=
×=
2
2

λ
λ

6. 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

7. 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
Depth(m)
L-actual (m)
L-vibrometer (m)
L-ansys (m)

8. Plated Study
Comparison of Major Modes Between
Plated and Unplated Blocks
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
7000.0
8000.0
9000.0
10000.0
1 2 3 4 5 6 7 8
Mode #
ModalFrequency(Hz)
Unplated modes (Hz)
Plated modes (Hz)

9. Application to Blast Furnace Wall
Ring B
Ring A

10. 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 2.4
0
2
4
6
8
10
12
14
X: 0.785
Y: 12.56
Frequency (kHz)
Magnitude
Frequency Comparison - Ring A, Position #1
X: 1.04
Y: 4.649
Apr06
Jul06

11. Blast Furnace Application – Method A Results
April and July Furnace Profiles - Ring A
0
1
2
3
4
5
1
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
5
1
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

12. 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 3
0
0.5
1
1.5
2
2.5
Frequency (kHz)
Magnitude
Frequency Comparison - Ring A, Position #1
Aug05
Oct05
Apr06
Jul06

13. Blast Furnace Application – Method B Results
Blast Furnace Depth Measurements - Ring A
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
1
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
5
1
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

14. 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)
Heightaboveplatform(m)
Outer Wall
JUL w rt APR
JUL w rt AUG
Inner 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)
Heightaboveplatform(m)
Outer Wall
JUL w rt APR
JUL w rt AUG
Inner Wall
July 06 wrt April 06 July 06 wrt Aug 05

15. 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

16. 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

17. 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.