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Laporan Tugas Akhir
ANALISIS RESIKO PRESSURE VESSEL DENGAN RISK BASED INSPECTION API 581
DAN STUDI EKSPERIMENTAL KARAKTERISTIK KOROSI BAHAN SHELL PRESSURE VESSEL PADA MEDIA GAS H2S DI
HESS (INDONESIA – PANGKAH) LTD
Oleh:
James Tinambunan NRP 2709100093
Dosen Pembimbing:
Prof. Dr. Ir. Sulistijono, DEA
Jurusan Teknik Material dan Metalurgi FTI – ITS Surabaya
2013
Perumusan Masalah
2. Bagaimana pengaruh konsentrasi H2S yang terkandung dalam gas alam terhadap laju korosi pressure vessel SA516 GR 70?
1. Bagaimana tingkat resiko (risk level) pada pressure vessel dengan metode semi kuantitatif RBI API 581?
Perumusan Masalah
Batasan Masalah
1. Analisis resiko yang dilakukan berupa metode semi-kuantitatif RBI API 581
2. Penelitian yang dilakukan merupakan pressure vessel di HESS (Indonesia-Pangkah) Ltd
3. Dimensi pemotongan material dianggap homogen
4. Kehalusan permukaan benda uji dianggap homogen dan tidak mempengaruhi korosi yang terjadi
Tujuan
1. Memprediksi tingkat resiko pada pressure vessel dengan
metode semi-kuantitatif RBI API 581
2. Menentukan pengaruh konsentrasi H2S yang terkandung
dalam gas alam terhadap laju korosi pressure vessel
SA516 GR 70
Tujuan
Manfaat
Mengetahui risk level dan laju korosi pada pressure
vessel sehingga bisa digunakan untuk memprediksi
perencanaan inspeksi serta membantu menentukan
metode maintenance untuk menghindari/mengurangi
resiko kegagalan
Manfaat
TINJAUAN PUSTAKA
Analisa Resiko
Probability of Failure
Consequence of Failure RISK
Analisa Resiko
Metode Analisa Resiko
1. Analisa Kualitatif
2. Analisa Semi-kuantitatif
3. Analisa Kuantitatif
Metode Analisa Resiko
Risk Based Inspection
Hubungan Antara Frekuensi Inspeksi dengan Tingkat Resiko
Risk Based Inspection
Likelihood Analysis (Analisa Peluang Kegagalan)
TMSF:
1. Thinning
2. Stress Corrossion Cracking (SCC)
3. High Temperature Hydrogen Attack (HTHA)
4. Furnace Tubes Failure
5. Mechanical Fatigue (hanya untuk sistem perpipaan)
6. Brittle Fracture
7. External Damage
8. Equipment Linings Damage
Likelihood Analysis
1. Menentukan fluida representatif yang terlepas beserta sifat-
sifatnya.
2. Memilih ukuran lubang kebocoran.
3. Estimasi jumlah total fluida yang dapat terlepas.
4. Mendefinisikan tipe dari kebocoran.
5. Pemilihan fase final dari fluida yang terlepas (gas atau cair).
6. Evaluasi respon setelah fluida terlepas.
Consequence Analysis
Risk Level Risk Level
Pressure Vessel
Jenis-jenis pressure vessel:
1. Cylindrical pressure vessel
a. Vertical cylindrical pressure vessel
b. Horizontal cylindrical pressure vessel
\
Horizontal Pressure Vessel
Pressure Vessel
Pressure Vessel
2. Spherical pressure vessel
Komponen-komponen pressure vessel:
1. Shell
2. Head
3. Support
4. Accessories
Pressure Vessel
METODOLOGI PENELITIAN
Diagram Alir Start
Identifikasi dan
Perumusan Masalah
Studi Literatur
Analisa Risk Based
Inspection API 581
Consequence of Failure Probability of Failure
Screening Damage
Mechanism
Index (RBI API 581):
-Thinning
- Component Linings
- External Damage
- SCC
- HTHA
- Mechanichal Fatique
- Brittle Fracture
Damage Factor
Risk Score
Apakah semua
Penilaian
dan Penghitungan
telah selesai?
Pengumpulan Data
Analisa Data
dan Pembahasan
End
NoYes
Leak Impact Factor
Kesimpulan dan Saran
Studi Eksperimental
Karakteristik Korosi Bahan
Shell Pressure Vessel Pada
Media Gas H2S
Preparasi Spesimen
A516 GR 70
Pengujian
Weight Loss
Pressure Vessel
1. Likehood of Failure / Probability of Failure
Mekanisme kegagalan berdasarkan kriteria TMSF
Kategori keefektifan inspeksi
Menentukan TMSF berdasarkan a.r/t, jumlah inspeksi, dan keefektifan inspeksi
Menghitung faktor overdesign
Menjumlahkan peluang terjadinya kegagalan dan mencocokkan ke dalam tabel.
2. Consequence of Failure
Tipe kebocoran untuk ukuran lubang (¼, 1, 4, dan 16 inch)
Laju kebocoran gas (sonik atau subsonik) atau laju kebocoran liquid
Reduksi laju kebocoran berdasarkan sistem deteksi dan isolasi
Luas daerah kerusakan dan luas daerah berbahaya
Reduksi luas daerah kerusakan dan luas daerah berbahaya berdasarkan sistem mitigasi
Risk Based Inspection
Alat dan Bahan
Alat:
1. Mesin potong
2. Gerinda
3. Mesin bor
4. Kertas gosok grade 200, 400, 800, dan 1000
5. Neraca digital
6. Kamera
7. Jangka sorong
8. Wadah kaca bertutup
9. Tali pancing
10. Masker
Bahan:
1. Material SA516 GR 70
2. Larutan HCl 0,5 M
3. FeS
Studi Eksperimental Karakteristik Korosi Bahan Shell Pressure Vessel Pada Media Gas H2S
Alat dan Bahan
Spesimen Uji:
Pengujian Weight Loss:
Preparasi Larutan:
Penelitian laju korosi SA516 Gr 70 menggunakan gas
H2S sebanyak 0,02 mol, 0,04 mol, dan 0,06 mol .
FeS(s) + 2 HCl(aq) ↔ FeCl2(aq) + H2S(g)
m : 0,02 mol 0,04 mol --- ---
r : 0,02 mol 0,02 mol 0,02 mol 0,02 mol
s : 0 0,02 mol 0,02 mol 0,02 mol
Mol FeS = 𝑚𝑎𝑠𝑠𝑎 𝐹𝑒𝑆
𝑀𝑟 𝐹𝑒𝑆
0,02 = 𝑚𝑎𝑠𝑠𝑎 𝐹𝑒𝑆
87,9
Massa FeS = 1,758 gr
M = massa HCl
Mr HCl x
1000
Volume HCl
0,5 = 0,04 x 1000
Volume HCl
Volume HCl = 80 mL
Studi Eksperimental Karakteristik Korosi Bahan Shell Pressure Vessel Pada Media Gas H2S
Alat dan Bahan
Prosedur Pembersihan Produk Korosi (ASTM G1-03)
1. Menyiapkan larutan/reagent, yaitu:
1000 mL Hydrochloric Acid (HCl, sp gr 1.19)
20 gr Antimony Trioxide (Sb2O3)
50 gr Stannous Chloride (SnCl2)
2. Memanaskan pada temperatur 30oC
3. Spesimen yang terkorosi dicelupkan ke dalam larutan yang telah dipanaskan dan ditunggu
selama 25 menit
4. Spesimen dikeringkan menggunakan dryer
5. Penimbangan spesimen menggunakan neraca digital
Studi Eksperimental Karakteristik Korosi Bahan Shell Pressure Vessel Pada Media Gas H2S
Analisa Data dan Pembahasan
Alat dan Bahan Data Umum Pressure Vessel
Item Diameter Length Total Corrosion
No. Press. (barg) Temp. (°C) Press. (barg) Temp. (°C) (mm) (mm) Volume (m3) Allowance (mm)
Inlet Hydrocarbon Receiving
Separator and Separation
Hydrocarbon Receiving
and Separation
Hydrocarbon Receiving
and Separation
Amine Contactor
Inlet KO Drum
Amine Surge
Vessel
Amine Overhead
Gas KO Drum
Low Temperature Gas Dew Point and
Separator Metering
1st Stage-Flash Gas Condensate Stabilization
Suction Scrubber and Flash Gas Compression
2nd Stage-Flash Gas Condensate Stabilization
Suction Scrubber and Flash Gas Compression
Material
1 131-V-01 46,8 29,8
Design OperatingTag No. Description Unit Process
70 65/0 8,91500 4800
4 135-V-01 H2S Removal System
5 135-V-02 H2S Removal System
2 132-V-01 Liquid Separator
3 132-V-02 Production Separator
8 135-V-14 Amine Drain Vessel H2S Removal System
6 135-V-09 H2S Removal System
7 135-V-10 Amine Flash Drum H2S Removal System
15 144-V-01 Closed Drain Vessel Drain System
13 143-V-01 HP Flare KO Drum Flare System
14 143-V-02 LP Flare KO Drum Flare System
11 139-V-04
12 141-V-01 Fuel Gas Scrubber Fuel Gas System
9 137-V-05
10 139-V-03
45,8 28,2
10 90/0 1 45
15 28
70 65/0 46,6 28,6
20 65/0
70 65/0
3,5 150/0 0,3/0,1 118,5/17,2
45,5 44,4
8 65/0 6,05 30,9
70 65/0
70 150/0 21,5 72,8
36 80/-29 20,9 49,52
70 75/-13 32,3 10,9
30 135/0 10,2 74
3,5 200/0 0,3 26,5
9 150/-46 4,5/0,1 100,1/-16,8
3,5 100/-46 0,1 30,1/-39,4
1800 5512 15,44
1220 4978,4 6,229
1042 2642
2400 5600 28,944
800 3250 1,669
4000 9750 139,207
2,4
1650 4700 11,212
1220 3962,4 18,76
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
2800 5700 40,815
2900 10600 76,349
1200 2400 3,161
1350 3300 5,368
1000 2800 2,382
1700 4216,4 6,647
3
6
3
3
3
3
3
0
3
3
3
3
6
3
3
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
SA 516 GR 70
Alat dan Bahan Representative Fluid dan Kategori Peralatan
Item Tag No. Representative
No. Fluid 1 131-V-01 C1 - C2 2 132-V-01 C1 - C2 3 132-V-02 C1 - C2 4 135-V-01 C1 - C2 5 135-V-02 C1 - C2 6 135-V-09 C1 - C2 7 135-V-10 C1 - C2 8 135-V-14 C1 - C2 9 137-V-05 C1 - C2 10 139-V-03 C3 - C4 11 139-V-04 C3 - C4 12 141-V-01 C1 - C2 13 143-V-01 C3 - C4 14 143-V-02 C1 - C2 15 144-V-01 C6 - C8
Item Tag No. Inventory (lbs) Category
No.
1 131-V-01 1772,34071 B 2 132-V-01 3074,712423 B 3 132-V-02 1240,439358 B 4 135-V-01 477,9345735 A 5 135-V-02 2232,751016 B 6 135-V-09 3735,85525 B 7 135-V-10 5763,890957 B 8 135-V-14 27721,59924 C 9 137-V-05 1323,679629 B
10 139-V-03 212,7740453 A 11 139-V-04 684,3445628 A 12 141-V-01 474,3500642 A 13 143-V-01 9733,424557 B 14 143-V-02 629,4796612 A 15 144-V-01 61549,30156 C
Alat dan Bahan
Sistem Deteksi : B
Sistem Isolasi : B
Estimasi Durasi Kebocoran Sesuai Sistem Deteksi dan Sistem Isolasi
Ukuran Lubang ¼ inch 1 inch 4 inch 16 inch
Estimasi Kebocoran 40 menit 30 menit 20 menit 0
Laju Kebocoran Gas/Liquid Step I
1. Enter representative material
2. Enter the inventory category for the equipment
2a. Enter the inventory value lbs
3 Enter detection rating
4. Enter isolation rating
1/4 in. 1 in. 4 in. 16 in.
40 30 20 0
min min min min
6. Enter operating pressure psia
7. Circle gas or liquid, depending on the phase of the liquid in the equipment
8. Enter the process temperature °F
9. Calculate and enter transition pressure (Ptrans) psia
Is fluid pressure inside the equipment greater than transition pressure?
If yes, circle "sonic"
If no, circle "subsonic"
HOLE SIZES 1/4 in. 1 in. 4 in. 16 in.
3,15 50,46 807,43 12918,85
lb/sec lb/sec lb/sec lb/sec
lb/sec lb/sec lb/sec lb/sec
lb/sec lb/sec lb/sec lb/sec
Step II
Devide maximum permissible released inventory by the appropiate 9,377464 0,585395 0,036584 0,002287
release rate = Line 2 : Line 11. Divide by 60 to get minutes. Enter value min min min min
15. Type of release cont. cont. inst. inst.
16. Enter the NBP of the fluid at atmospheric pressure °F
17. Enter the phase of the fluid after the release
Enter the initials of the circled terms in Line 15 and Line 17.
This is the release type
Look at Line 5 and Line 14. For each hole size, enter the lesser of the two. 9,377464 0,585395 0,036584 0
This is the release duration min min min min
Enter the inventory of the equipment being evaluated. This is the instan-
taneous release mass
Gas Liquid
GAS RELEASE RATE
26,97
Sonic Subsonic
678,77
LIQUID RELEASE RATE
Operating Unit: Hydrocarbon Receiving and Separation
Equipment No : 131-V-01
Description : Inlet Separator
5.
PART A RELEASE RATE CALCULATION
C1 - C2
B
B
B
CALCULATE RELEASE RATE
1772,34071
Esimate leak duration based on detection and isolation systems
85,64
10.
11. Sonic release rate
12. Subsonic release rate
193
1772,34071 lbs.
13. Use liquid release rate to calculate release rate. Enter rate
14.
Gas
DETERMINATION OF PHASE AFTER RELEASE
DETERMINE RELEASE TYPE FOR EACH HOLE SIZE
18.
19.
20.
cont. inst.
DETERMINATION OF INSTANTANEOUS RELEASE MASS
cont. inst.
Alat dan Bahan
Dalam peralatan pressure vessel ini hanya faktor thinning yang memiliki kemungkinan
disebabkan oleh fluida servis yang berada di dalamnya yang berupa C1-C2, C3-C4, dan
C6-C8. Contoh Worksheet Likelihood Analysis untuk 131 – V – 01 :
Likelihood Analysis
PART B
1. Thickness (mm) 48
2. The equipment age (year) 6
3. Corrosion Allowance (mm) 6
4. Corrosion rate 0,13
5. Calculation of ar/t 0,01625
6. Thinning Type General Thinning
7. Operating Temperature (°F) 85,64
8. Operating Pressure (barg) 46,8
9. MAWP (barg) 70
10. Inspection Effectiveness Category Highly Effective
11. Number of Inspection 3
12. Determination of TMSF 1
13. Adjustment to TMSF for Overdesign 0,5
14. Adjustment to TMSF for On-Line Monitoring
15. Combined TMSF 0,5
16. Probability of Failure category 1
LIKELIHOOD ANALYSIS
TMSF THINNING
Alat dan Bahan
Worksheet consequence analysis untuk 131 – V – 01 :
Consequence Analysis
1. Enter representative material
1/4 in. 1 in. 4 in. 16 in.
2. Enter release type cont. cont. inst. inst.
3a. Sonic release rate calculation (lb/sec) 3,15 50,46 807,43 12918,85
3b. Subsonic release rate calculation (lb/sec)
3c. Liquid release rate calculation (lb/sec)
4. Detection rating
5. Isolation rating
6. Enter adjusted release rate or mass 2,6775 42,891 686,3155 10981,02
Look at Equipment Damage equations in Consequence Equation and
replace "x" by adjusted release rate or mass (Line 6) (ft²)
Look at Area of Potential Fatalities in Consequence Equation and
replace "x" by adjusted release rate or mass (Line 6)
9a. Mitigation system
9b. Reduce consequence
9c. Adjusted Equipment Damage Area (ft²) 84,66514 1283,065 2445,209 15670,24
10. Adjusted Area of Fatalities (ft²) 212,3607 3044,567 4711,501 30193,89
Inventory Blowdown
25%
CONSEQUENCE REDUCTION
RELEASE TYPE
B
B
8.
POTENTIAL FATALITIES AREAS
283,1477 4059,422 6282,002 40258,52
Part C.1 FLAMMABLE CONSEQUENCE CALCULATIONS
HOLE SIZES
7. 112,8868 1710,753 3260,279 20893,66
C1 - C2
REPRESENTATIVE MATERIAL
RELEASE RATE OR MASS
DETECTION AND ISOLATION RATING
ADJUSTMENTS FOR FLAMMABLE EVENT MITIGATION
EQUIPMENT DAMAGE AREA
Alat dan Bahan
Worksheet resiko 131 – V – 01 :
Tingkat Resiko
1/4 in. 1 in. 4 in. Rupture
1. Enter the generic failure frequency by hole size 0,00004 0,0001 0,00001 0,000006
2. Calculate Sum of Failure Frequencies (per year)
3. Calculate fraction contribution of each hole size (ft²) 0,25641 0,641026 0,064103 0,038462
4a. Flammable consequence of equipment damage area (Line 9, Part C.1) (ft²) 84,66514 1283,065 2445,209 15670,24
4b. Flammable consequence of potential fatalities area (Line 10, Part C.1) (ft²) 212,3607 3044,567 4711,501 30193,89
4. Flammable consequence result 212,3607 3044,567 4711,501 30193,89
5. Multiply each value in Line 4 by the corresponding fraction in Line 3 (ft²) 54,45146 1951,646 302,0193 1161,303
6. Copy toxic consequence results (Line 10, Part C.2)
7. Multiply each value in Line 6 by the corresponding fraction in Line 3 (ft²)
8. Sum the values from Line 5. This is the Flammable Consequence area value
9. Sum the values from Line 7. This is the Toxic Consequence area value
Convert the value from either Line 7 or Line 8 to a category according to
Appendix VIII, Table B-3. This is the Consequence Category
11. Copy the Likelihood Category from Part B
Convert the categories from Lines 10 and 11 to a risk category using
Appendix VIII, Figure 2.
Part D RISK CALCULATIONS
HOLE SIZES
1
Medium
10.
0,000156
12.
3469,419731
D
Alat dan Bahan Risk Category Item
No.
D Medium
1 C Medium
1 C Medium
1 C Medium
C Medium
1 D Medium
1 D Medium
1 D Medium
D Medium
1 B Low
D1 Medium
2 C Medium
Consequence Risk Category
1 D Medium
2 D Medium
1 D Medium
11 139-V-04
12 141-V-01
9 137-V-05
10 139-V-03
Likelihood
1
1
1
8 135-V-14
6 135-V-09
7 135-V-10
1 131-V-01
Tag No.
4 135-V-01
5 135-V-02
2 132-V-01
3 132-V-02
15 144-V-01
13 143-V-01
14 143-V-02
Alat dan Bahan Matriks Resiko
A B C D E
5
4
3
2 1 1
1 1 4 8
Likelihood
Category
Consequence Category
High
Medium High
Medium
Low
Alat dan Bahan Hasil Pengujian Weight Loss
Berat Awal Berat Akhir Kehilangan Berat Awal Berat Akhir Kehilangan Berat Awal Berat Akhir Kehilangan(gr) (gr) Berat (gr) (gr) (gr) Berat (gr) (gr) (gr) Berat (gr)
0,02 32,7 32,55 0,15 36,77 36,6 0,17 32,68 32,5 0,18
0,04 33,6 33,44 0,16 34,49 34,29 0,2 33,52 33,2 0,32
0,06 34,06 33,83 0,23 35,61 35,26 0,35 35,29 34,76 0,53
Spesimen 3(6 hari)H2S
(mol)
Spesimen 1(2 hari)
Spesimen 2(4 hari)
Alat dan Bahan Laju Korosi
Spesimen 1 Spesimen 2 Spesimen 3(2 hari) (4 hari) (6 hari)
0,02 39,41552602 22,33546474 15,76621041
0,04 42,04322775 26,27701734 28,0288185
0,06 60,43713989 45,98478035 46,42273064
H2S (mol)Laju Korosi (mpy)
KESIMPULAN DAN SARAN
Alat dan Bahan
1. Terdapat 1 buah pressure vessel yang berada pada low risk dan 14 buah pressure vessel lainnya berada pada medium risk.
2. Tidak diperlukan langkah mitigasi karena pressure vessel dalam kategori aman.
3. Semakin tinggi konsentrasi gas H2S, maka laju korosinya semakin tinggi.
Kesimpulan
Alat dan Bahan
1. Meskipun pressure vessel dalam kategori aman (low risk dan medium risk), pemantauan terhadap peralatan perlu dilakukan agar resikonya tidak menjadi tinggi.
2. Untuk penelitian yang lebih akurat perlu dilakukan analisis resiko secara kuantitatif.
3. Perlu melakukan pengujian weight loss yang disesuaikan dengan kondisi yang sebenarnya meliputi konsentrasi gas H2S, temperatur, dan kecepatan alir gas H2S di dalam pressure vessel sehingga didapatkan nilai laju korosi yang lebih akurat.
Saran
SEKIAN
DAN
TERIMA KASIH