API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

2.B-40 API RECOMMENDED PRACTICE 581
Table 2.B.4.5—High Temperature H 2 S/H 2 Corrosion—Estimated Corrosion Rates for 9Cr-1Mo (mpy)
H 2 S
(mole %)
Type of
Hydrocarbon
Temperature (°F)
425 475 525 575 625 675 725 775 825 875 925 975
0.002
0.0035
0.008
0.035
0.08
0.30
0.75
1.0
Naphtha 1 1 1 1 1 2 3 4 5 7 9 12
Gas oil 1 1 1 1 2 3 5 7 10 13 17 23
Naphtha 1 1 1 2 2 4 6 8 11 15 19 25
Gas oil 1 1 2 3 5 7 11 15 21 28 37 48
Naphtha 1 1 1 2 3 5 7 10 14 20 26 34
Gas oil 1 1 2 4 6 10 14 20 27 37 49 64
Naphtha 1 1 2 4 6 9 13 18 25 34 45 59
Gas oil 1 2 4 7 11 17 24 35 48 65 86 110
Naphtha 1 2 3 4 7 11 16 22 31 42 55 72
Gas oil 2 3 5 9 13 20 30 42 59 79 110 140
Naphtha 1 2 4 7 10 16 23 32 45 61 80 100
Gas oil 2 4 7 12 19 30 43 61 85 120 150 200
Naphtha 1 3 4 7 12 18 26 37 51 68 90 120
Gas oil 3 5 8 14 22 33 49 69 96 130 170 220
Naphtha 2 3 6 9 14 22 32 45 63 85 110 150
Gas oil 3 6 10 17 27 41 60 86 120 160 210 280