XRF Advancements Improve Detection of Trace Silicon in Carbon Steel in On-Line, High-Temperature Process Piping and Components

XRF Advancements Improve Detection of Trace Silicon in Carbon Steel in On-Line, High-Temperature Process Piping and Components

Olympus | Michael W. Hull, Alex Thurston, Dianne Hillhouse ASNT | Long Beach, CA | 27 October 2016

Advances in low-Si testing

Importance of low-Si testing

Challenges of low-Si testing

Importance of low-Si testing

Why positive material identification (PMI)?

“Final Investigation Report: Chevron Richmond Refinery Pipe Rupture and Fire” U.S. Chemical Safety and Hazard Investigation Board. Report No. 2012-03-I-CA. January 2015 “Positive Material Verification: Prevent Errors During Alloy Steel Systems Maintenance” Safety Bulletin, U.S. Chemical Safety and Hazard Investigation Board. Report No. 2005-04-B. October 2006

Why positive material identification (PMI)?

Sulfidic corrosion

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Scale formation Internal diffusion

Factors affecting sulfidic corrosion

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Tem

pera

ture

Source: NCSS Statistical Software, https://www.ncss.com/software/ncss/ncss-plots-and-graphs/

SH

SS

S

SH2CO2H

S

R

CO2H H2

[ ]n [ ]n

[ ]n [ ]n

[ ]n

Alloy effects

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Chromium Silicon

a l l o y I n g c o n t e n t

FeCr2S4

Corrosion Rate vs Silicon Content

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

Silicon Content (Weight %)

Cor

rosi

on R

ate

(mpy

)

Alloy effects

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Source: American Petroleum Institute Recommended Practice 939-C: Guidelines for Avoiding Sulfidation (Sulfidic) Corrosion Failures in Oil Refineries, 2nd Ed, Annex C

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time • Knowledge • Risk

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1940 1950 1960 1970 1980 1990 2000 2010 2020

Con

stru

ctio

n

Und

erst

andi

ng

History and variation in steel specifications

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C

(max) Si

(min) P

(max) S

(min) Ti

(max) V

(max) Cr

(max) Mn

(max) Fe Ni

(max) Cu

(max) Mo

(max) A53B 0.30* --- 0.05 0.045 --- 0.08 0.4 1.20* bal. 0.4 0.4 0.15 API 5L 0.28* --- 0.08* 0.03 0.06 --- --- 1.85* bal. --- --- --- A105 0.35* 0.1 0.035 0.04 --- 0.08 0.3 1.05* bal. 0.4 0.4 0.12 A106 0.35* 0.1 0.035 0.035 --- 0.08 0.4 1.06* bal. 0.4 0.4 0.15 A181 0.35* 0.1 0.05 0.05 --- --- --- 1.10 bal. --- --- --- A234 0.35* 0.1 0.05 0.058 --- 0.08 0.04 1.06* bal. 0.04 0.04 0.15

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API Recommended Practice 939-C - Guidelines for Avoiding Sulfidic Corrosion Failures in Oil Refineries

§ Result of naturally occurring sulfur compounds found in crude oil.

§ Causes accelerated corrosion in steel fittings, piping, heater tubes, and pressure vessels when the oil is heated for separation.

§ A significant cause of leaks and failures of piping systems within the refining industry.

§ Process streams with hydrogen free, sulfurous material may exhibit corrosion in carbon steel piping with less than 0.1% Si (McConomy Curves)

–  Increasing Cr content of the alloy can provide increasing resistance to this form of corrosion

§ Streams with a combination of hydrogen and sulfur-containing materials at elevated temperature can corrode steels with Cr levels below 12% (i.e. non-stainless alloys, Couper-Gorman curves)

–  Recommended to use 18Cr-8Ni stainless steel to avoid corrosion

Importance of low-Si testing

Challenges of low-Si testing

Challenges to trace silicon testing

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Challenging

Environmental variables

Contaminations Low concentrations

Surface preparation

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Prepare & verify

Coatings, platings Residual paint Corrosion, scale, oxide layer

Sand-blasting (Residual Si)

Shot-blasting (residual from iron pellets)

Metallic dust

Environmental variables

Source: U.S. Energy Information Administration, U.S. Energy Mapping System, http://www.eia.gov/state/maps.cfm Source: Climate.gov https://www.climate.gov/maps-data/data-snapshots/averagetemp-monthly-cmb-2015-10-00?theme=Temperature

Low concentration

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0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100

Fluo

resc

ence

Yie

ld

Atomic Number

Fluorescence yield of elements

K Series

L Series

M Series

Mass attenuation coefficient (Fe) Si 2457.94 Cr 110.97 Mn 87.85

Low concentration

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High absorbance

Low emittance

Advances in low-Si testing

Importance of low-Si testing

Challenges of low-Si testing

Vanta™ handheld XRF analyzer engineering

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Temperature control

Vanta analyzer engineering

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Temperature control

Vanta analyzer engineering

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Temperature control

0

10

20

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60

70

11:30 AM 12:00 PM 12:30 PM 1:00 PM 1:30 PM 2:00 PM 2:30 PM 3:00 PM 3:30 PM

Instrument Temperature

Spot 1 Spot 2

Vanta analyzer engineering

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Temperature control

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Vanta analyzer engineering Temperature control

0

10

20

30

40

50

60

70

11:30 AM 12:00 PM 12:30 PM 1:00 PM 1:30 PM 2:00 PM 2:30 PM 3:00 PM 3:30 PM

Instrument Temperature

Spot 1 Spot 2

Instrument Stability

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0

5

10

15

20

25

30

35

40

45

50

55

60

65

6.390

6.395

6.400

6.405

6.410

6.415

6.420

6.425

6.430

6.435

6.440

6.445

6.450

0 100 200 300 400 500 600 700 800 900 1000

Tem

pera

ture

(°C

)

Volta

ge (K

eV)

Stability with Temperature Cycling

Manganese Peak Temperature

Less than 0.002 KeV variance

Instrument Stability

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0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00

10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00 18.00 19.00 20.00

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

316 SS Measurement with Temperature Cycling

Cr Mn Ni Mo

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0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60

Inst

rum

ent T

empe

ratu

re (°

C)

Sequential Test Number

Instrument temperature during hot testing

400 F 500 F 600 F

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0.00

0.10

0.20

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0.40

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0.60

0.70

0.80

0.90

1.00

1.10

1.20

0 5 10 15 20 25 30 35 40 45 50 55 60 65

Con

cent

ratio

n (%

)

Sequential Test Number

Mn/Mo concentration values during hot testing

Mn 400 F Mo 400 F Mn 500 F Mo 500 F Mn 600 F Mo 600 F

400 °F 500 °F 600 °F

Mn Mo Mn Mo Mn Mo Certified Value 0.86 0.493 0.86 0.493 0.86 0.493 Average (Vanta) 0.88 0.502 0.88 0.504 0.88 0.504 Minimum 0.83 0.486 0.83 0.488 0.83 0.490 Maximum 0.94 0.518 0.92 0.525 0.94 0.527 RSD 6.17% 3.19% 4.95% 3.65% 6.11% 3.72%

Window for high temperature testing

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Before After

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y = 1.0737x - 0.0123 R² = 0.9949

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Vant

a M

easu

rem

ent

Certified Assay

Si performance on low alloys

Silicon concentration Alloy grade CS 1117 CS 1144 CS 1050 CS 1018 CS 4140 C ½ Mo

Assay value 0.05 0.18 0.211 0.252 0.28 0.331 Vanta measurement 0.04 0.18 0.219 0.264 0.27 0.348 Standard deviation 0.008 0.012 0.0140 0.0146 0.018 0.0116

Accuracy

Bias

Precision

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0.00

0.03

0.05

0.08

0.10

0.13

0.15

0.18

0.20

0.23

0.25

0.28

0.30

0.33

0.35

0.38

0.40

0 5 10 15 20 25

Con

cent

ratio

n (%

)

Sequential Test Number

Repeatability of Si measurements

CS 1018 CS 4140 CS 1144 CS 1050 C 1/2 Mo

Future Endeavors § Certified samples of lower concentration

§ High temperature calibration for light elements

§  Industrial partners for field testing