General Manager, MLNG Tiga Sdn Bhd, PETRONAS. Senior Project Manager, Foster Wheeler Energy Ltd.

Transcription

1 General Manager, MLNG Tiga Sdn Bhd, PETRONAS Senior Project Manager, Foster Wheeler Energy Ltd. 1

2 BORNEO in the LNG World BINTULU BRUNEI BONTANG 2

3 Train 7 Fire Incident Introduction / Background Mitigation & Lesson Learned Business Recovery Plan Conclusion 3

4 PETRONAS LNG Complex The PETRONAS LNG Complex is an integrated plant consisting of : Malaysia LNG S/B - Train 1, 2, & 3 Malaysia LNG Dua S/B - Train 4, 5, & 6 Malaysia LNG Tiga S/B - Train 7 & 8 With a total production capacity of 23 Mtpa, the complex has become the world s largest LNG plant in a single location 4

5 Aerial View of PETRONAS LNG Complex MLNG Dua MLNG MLNG Tiga 5

6 Background Information on Train 7 MLNG Tiga nameplate capacity is 3.9 Mtpa per train MLNG Tiga Train 7 started up in March 2003 Performance test completed successfully in June 2003 Fire incident occurred on August 16 th, 2003 in the Waste Heat Recovery Unit (WHRU) 6

7 3-D View of MLNG Tiga Train 7 Liquefaction North (F7E) North Main piperack and Air fin cooler (F7Y) Liquefaction South (F7C) Liquefaction Middle (F7D) Sulfinol (F7B) SS 43 SS 56 FAR 7 Fractionation (F7A) MR/Propane Compressor (F7H) South Hot Oil (F7G) Incident Area Dehydration (F7F) 7

8 Background Information on WHRU Waste exhaust gas from gas turbine of propane compressor is used to heat regeneration gas for dryers and hot oil system for reboilers The exhaust gas passes through the Y piece of the WHRU unit where a regeneration coil and 5 hot oil coils are located The unit is refractory lined and the operating temperature is above 500 C 8

9 Location of Incident Geometry Model of C3 GT Exhaust & WHRU COMMON STACK REGENERATION GAS HEATER (E-91303) HTF HEATER (E-95101) Train 7 WHRU prior to incident PROPANE COMPRESSOR GAS TURBINE FLUE GAS 9

10 Train 7 Fire Incident On 16 th August 2003 at pm, following a trip of the C3C GT (7KG-91440) in Train 7, a fire occurred in the WHRU Plant emergency response immediately initiated and MLNG First Intervention Team (FIT) was mobilized to the scene MLNG Automated Call-Out System (ACOS) and Bintulu Emergency Mutual Aid (BEMA) were activated to assist in the incident The fire external to the exhaust duct of the C3C GT was extinguished within half an hour No casualties or injuries occurred in the incident 10

11 Schematic Arrangement of the Equipment Noise Enclosure Compressor House Exhaust System Regeneration Gas Heater 7E HTF Heater, 7E Combined Stack 7A Acid Gas Incinerator 7A Exhaust Duct Propane Gas Turbine 7KG Grade Fire Location Waste Heat Recovery Unit (WHRU) 11

12 PHOTOS: Before & After The Incident (1) BEFORE AFTER Close-Up on the Damage of C3 GT Exhaust Plenum (Top View) 12

13 PHOTOS: Before & After The Incident (2) BEFORE AFTER Damaged WHRU Ducting to Stack View from North-East of WHRU and Exhaust Stack 13

14 PHOTOS: Before & After The Incident (3) BEFORE AFTER Damaged Piping View from South-East of WHRU and Exhaust Stack 14

15 Initial Investigation An investigation Team was immediately setup on 17 th August 2003 that comprises plant operator, project team, EPCC contractor, GT vendor (NP/GE), and SGSI Major finding was gas leak due to a crack in a weld at one of the tube to header joints of the regeneration gas coil 15

16 PHOTOS : Crack on the Tube to Header Weld Joint Photos showing the crack in the weld at one of the tube to header joints of the the regeneration gas coil - 2 nd tube 16

17 Incident Analysis Unrelated trip of turbine resulted in fuel gas closing off and turbine running to a stop Air drawn through turbine due to slow rotation of rotor and chimney effect of hot stack 02 content rose from 14% to 21 % Regeneration gas coil developed leak at joint between tube and header Plenum/ducting temperature remained high near the normal operating exhaust temperature of 570 C There was an auto ignition temperature at 537 C for air and natural gas causing an explosion inside the WHRU 17

18 The Severity of the Damages WHRU ducting was damaged beyond repair Hot oil coils were damaged Gas turbine plenum was extensively damaged Compressor & GT housing was extensively damaged Compressor was undamaged but needed full examination Turbine ancillary equipment was damaged Regeneration coils were not damaged 18

19 Teams Formed for Efficient Recovery Process Incident Investigation Team to find the root cause Business Recovery Team Interim Production Study Team Demolition Team Engineering & Re-HAZOP Teams to develop a safe redesign Reconstruction Team Insurance Claim Group 19

20 Analysis on the Welding Design The welds on the regeneration coil were deficient NDE was very difficult with the original welding design Improved welding design with nipolets for connection were recommended Having nipolets provide a stronger connection and allow full radiographic testing on each joint 20

21 Cross-Section Between the Tube and Header of the Original Weld A small section of the weld that maintained the connection A gap in the root pass of the weld 21

22 Original Welding Design Between the Tubes and Header Without Nipolets 22

23 Improved Welding Design Between the Tubes and Header Nipolets 23

24 The Re-HAZOP Analysis Re-HAZOP recommended safety valves (existing motorized valves) for isolation of the regeneration gas coil The regeneration gas would be blocked and vented from the coil to flare in the following events : : Detection of differential flow across the coil Loss of pressure in the coil During the trip of Gas Turbine For future designs, it is recommended that the coil header and the connection to be located outside the WHRU duct 24

25 Regeneration Coil Isolation & Depressurising Purge Gas To Regeneration Compressor Regeneration Gas To Drier Beds Regeneration Coil Regeneration Gas From Drier Beds Purge Gas From Scrub Column Overheads 25

26 PHOTOS: Train 7 Rebuild Work Installation of the new WHRU Ducting 26

27 The Recovery Process Initial estimate was 12 months to restart Train 7 considering delivery of regeneration & hot oil coils Interim production plan was developed to shorten the rebuild within 7 months by :-: Sharing hot oil from Train 8 Using the repaired regeneration coil Dedicated teams established for rebuild at site and in vendors works Dedicated transport arranged to expedite deliveries of replacement parts Train 7 restarted 3 weeks ahead of the revised target of 7 months Early March

28 Business Recovery Measures Measures taken to mitigate Train 7 supply :-: Replacement cargoes from within the PETRONAS LNG complex Deferment of cargoes & ETA changes Secured 3 cargoes from other LNG Suppliers 28

29 Conclusion Train 7 recovery was done safely and successfully mainly due to :-: Accurate identification of the root cause Remedy for the root cause implemented The installation of additional protection scheme Excellent spirit of teamwork & co-operation operation from dedicated teams especially our LNG Buyers and other LNG Suppliers 29

30 Mila Esker Terima Kasih 30