Overhaul-of-Centrifugal-Gas-Compressor.pdf

Step by step process of overhauling a single stage centrifugal compressor

1. PROCESS GAS COMPRESSOR
Failure
CASE STUDY

2. Process Gas compressor is a single stage
Centrifugal compressor
It’s considered to be the Heart Of DRP
industry
A mechanical failure occurred, leads to a sudden trip destroyed some parts.
And we will explore Rehabilitation of a compressor.
Procedures:
A. Dismantling and inspection.
B. Plan and Actions.
C. Final Assembly.
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3. A. Dismantling and Inspection
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4. Dismantling
Starting with strainer removal. IGV’s Removal.
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5. First look after removing IGV’s.5

6. Compressor Components
“Inspection”
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7. PG Compressor Components
As a machine, it could be divided it into 3 main partitions :
1. Inlet Guide Vans “IGV's.”
2. Inlet volute casing including:
2.1. Diffusers.
2.2. Impeller with stud& cup.
2.3. Dry Gas Seal.
2.4. Dry Gas Seal Casing.
3. Gear box including:
3.1. Shafts “H.S.S, L.S.S” with pinion& bull gears.
3.2. H.S.S. Bearings :
3.2.1. Journal compressor side.
3.2.2. Journal motor side.
3.2.3. Thrust bearing.
3.3. L.S.S. Bearings :
3.3.1. Combined bearing.
3.3.2. Journal bearing motor side.
3.4. Carbon rings.
3.5. Main oil gear pump drive& driven gears.
All parts excluded Coupling with spacer and Suction strainer.
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8. 1. Inlet Guide Vans
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9. Broken van found
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10. 2. Inlet Volute Casing includes
2.1. Diffuser.
2.2. Impeller.
2.3. Dry Gas Seal.
2.4. Dry Gas Seal Casing.
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11. 2.1.Diffusers
Destroyed blades in old diffusers
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12. Diffusers Body
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13. 2.2. Impeller
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14. Sections for destroyed parts14

15. Impeller cap and screw fixingit, both found thrown in suction line15

16. CapScrew16

17. 2.3. Dry Gas Seal “DGS”
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18. 2.4. Dry Gas Seal Casing
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19. 3. Gear Box
3.1. Shafts “H.S.S, L.S.S” with pinion& bull gears
3.2. H.S.S. Bearings :
3.2.1. Journal compressor side.
3.2.2. Journal motor side.
3.2.3. Thrust bearing.
3.3. L.S.S. Bearings :
3.3.1. Combined bearing.
3.3.2. Journal bearing motor side.
3.4. Carbon rings.
3.5. Main oil gear pump drive& driven gears.
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20. 3. Gear Box
Removing Gear Box Cover Gear Box review
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21. 3.1. Shafts
High Speed Shaft. “HSS”
Old one New One
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22.  Low Speed Shaft. “LSS”22

23. Bearings
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24. Bearings
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25. 3.2. H.S.S. Bearings
General arrangement25

26. 3.2.1. Journal Bearing compressor side
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27. Bearing issue27

28. Measurements28

29. Blue print29

30. Crush Test30

31. 3.2.2. Journal Bearing Motor side
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32. 3.2.3. Thrust Bearing
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33. 3.3. L.S.S. Bearings
General Arrangement
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34. 3.3.1. Combined Bearing34

35. 3.3.2. Journal Bearing Motor side35

36. 3.4. Carbon Rings36

37. 3.5. Oil Main Gear Pump Drive and Driven37

38. B. Plan And Actions
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39. •As per inspection the plan was :
➢IGV’s will be changed totally with respect to machining required.
➢A van less diffuser will be designed& fabricated instead of old one.
➢Replace Pinion shaft with all parts related; “Pinion shaft with bearings, carbon rings, DGS and
impeller".
And replacing both "combined and Journal bearing" in L.S. shaft.
➢Decided to repair damages which found in each of “Volute casing & Gearbox cover” with cold welding.
➢DGS casing will be machined and threaded for fittings of nitrogen, process gas inlets and nitrogen vent
seals.
➢Broken teeth in drive for main gear pump will be machined.
➢Expansion Joint in the discharge line will be tested to bechecked.
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40. 1.Inlet Guide Vans Assembly
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41. 2.1. New Diffuser41

42. 2.3. Dry Gas Seal42

43. 2.4. Dry Gas Seal Casing
Fitting and Thread issue
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44. Broken teeth in Main Gear pump Drive Gear
Teeth before machining Teeth after machining
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45. Gearbox & Volute casing repair45

46. C. Final Assembly
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47. 1. Install L.S. shaft, check clearance then install main gear pump.47

48. 2. Install H.S.S. with bearings then check clearances.
Install Half Bearings Install H.S. Shaft
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49. H.S.S. Assembly
Check Clearances Both Journal assembled Install Thrust Bearing
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50. 3. Backlash50

51. 4. Gears Blue Print51

52. 5. Install Carbon Rings52

53. 5. Install DGS Casing and fitting53

54. 6. Install Dry Gas Seal54

55. 7. Cover Gear Box55

56. 8. Installing Impeller56

57. Impeller final Assembly57

58. 9. Impeller Diffuser Clearance58

59. 10. Installing Diffuser then IGV59

60. 11. Suction Strainer then final Alignment60

61. THANK YOU
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