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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


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


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


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


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


2 132-V-01 Liquid Separator

3 132-V-02 Production Separator

8 135-V-14 Amine Drain Vessel 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



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

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