Vibration of Rotating Machinery Vibration of Rotating Machinery in Hawiyah Gas Plantin Hawiyah Gas Plant

King Fahd University of Petroleum and Minerals King Fahd University of Petroleum and Minerals Mechanical Engineering DepartmentsMechanical Engineering Departments

Presented by :

Ahmed Al-Jaafari

993714

Advisor:

Dr. Meyasser Al-Haddad

October 19,2004

OutlineOutline : :

Plant Overview Plant Overview Hawiyah Gas Plant ProcessesHawiyah Gas Plant Processes Vibration GroupVibration Group Case StudyCase Study ConclusionConclusion

Hawiyah Gas PlantHawiyah Gas Plant

Overview: Overview:

One of the newest plant.

The first completely non-associated gas plant

Completed four months ahead of schedule and under budget

Designed and built from scratch to meet the increased local demand for sales gas

Overview:Overview:

Plant production:

1530 MMSCFD sweet gas

50 MMSCFD sulfur

Increased the Kingdom's gas supply by 30 %.

Increase capacity 2,400 MMSCFD

Feed gas of the plant:

Juaf 407 MMSCFD (sweet)

Khuff 1305 MMSCFD (sour)

INLET AREA

GAS TREAT

DEHYDRATION &

DEW POINTCONRTOL

SALES COMPRESSORS

SULFUR RECOVERY

Juaf

Khuff(Haw)

Khuff(Har)

407 MMSCFD

1305 MMSCFD

1225 MMSCFD

50 MMSCFD

1587 MMSCFD

50 MMSCFD

USES OF PLANT

1530 MMSCFD

SALES GAS

HAWIYAH GAS PLANT PROCESSES

SCFD = Standard

Cubic Feet per Day

Maintenance Division

Work Shop Areas Maintenance CrewPlanersTechnical Support Unit

Quality Assurance Engineers Preventive Maintenance Vibration Group

Data Manager 2000

Vibration Group Devices and Software:

ADRE System (Automated Diagnosis for Rotating Equipments)

C.S.I. Machinery Analyzer (Computational System

Incorporated)

Data Manager2000 (DM 2000)

MOTOR COMPRESSOR

Y

X

A

Y

A

X

Y

X

A

X

Y

A

Vibration Readings

CASE STUDY

Bearing Defect:

1. Ball Pass Frequency of Outer race (BPFO)

2. Ball pass frequency of the Inner race (BPFI)

3. Fundamental Train Frequency (FTF)

4. Ball Spain Frequency (BSF)

Bearing Frequencies:

BPFO

BPFI

FTF

BSF

Bearing Frequencies Calculations

RPM = revolutions per minuteS = speed, revolutions per secondBd = ball or roller diameterNb = number of balls or rollersPd = pitch diameterθ = contact angle

1. Bearing Frequency Equations:

2. Rule of Thumb:

Bearing Frequencies Calculations

OR = 0.4 x (speed) x N

IR = 0.6 x (speed ) x N

FTF =0.4 x (speed)Where N is number of balls

Bearing Frequencies Calculations

3. Bearing Frequency Calculator:

Bearing Frequencies Calculations

Example: ( SKF 7311BECBJ)

BPFO = 142.125 HzBPFI = 217.85 HzFTF = 11.84 HzBSF = 52.19 Hz

1. Bearing Frequency Equations:

Since: S = 1800 RPM Bd = 0.9474 in Pd = 3.449 in θ = 40 0 Nb = 12 balls

OR = 0.4 (1800/60) 12= 144 HzIR = 0.6 (1800/ 60) 12 = 216 HzFTF = 0.4 (1800/60) = 12 Hz

2. Rule of Thumb:

3. Bearing Frequency Calculator:

(BPFO) = 146.27Hz(BPFI) = 213.73 Hz(FTF) =12.19 Hz(BSF) = 59.17 Hz

Failure Modes:Zone A Zone B Zone C Zone D

Bearing defect frequency

region

Bearing component natural freq.

region

Spike energy

Stage 1:

Stage 2:

Stage 3:

Stage 4:

500 2000

1X 2X 3X

Random high freq. Vibration

20-60 kHz

Example 1:

Bearing Frequency Calculation:

(BPFO) = 146.27Hz(BPFI) = 213.73 Hz(FTF) =12.19 Hz(BSF) = 59.17 Hz

Analysis:

Findings:•Non- of the bearing frequency match.

•Highlighted readings are the max.

FequencyAccel (G-s)

150.50.04031

236.60.08699

2620.04385

301.10.1609

383.80.8523

443.30.4951

451.70.3171

473.20.07534

486.50.07493

5020.05063

602.20.7262

620.20.2237

637.30.348

6500.3827

661.70.251

736.60.1028

7520.08873

761.40.08081

827.10.1279

856.90.1453

Example 1:

Zone A Zone B Zone CFindings:• 2 BPFO & 2 BPFI.

•Bearing natural components freq.

•Side band freq. around the bearing natural freq.

2 BPFO

2BPFI

Natural freq. & Side Band freq.

Recommendation:

The bearing is defective

in the third stage of failure and has to be replaced.

Note: harmonic means 1x(freq), 2x(freq), 3x(freq)

Replacing the bearing:

Example 2:

Inner race defect frequency (BPFI) = 332.6 HzOuter race defect frequency (BPFO) = 207.41 HzCage defect frequency (FTF) = 23.05 HzBall spin frequency (BSF) = 122.45 Hz

Bearing Frequency Calculation:

Analysis:

Findings:

• side-bands freq. around the highest amplitude.

• the highest amplitude (prime spike vib.)

= 6xBPFO

Example 2:

NoBPFO harmonics

12xBPFO414.82

23xBPFO622.23

34xBPFO829.64

45xBPFO1037.05

56xBPFO1244.46

67xBPFO1451.87

78xBPFO1659.28

89xBPFO1866.69

910xBPFO2074.1

1011xBPFO2281.51

1112xBPFO2488.92

1213xBPFO2696.33

1314xBPFO2903.74

FrequencyVelocity

in/sec

415.40.08629

625.70.1474

833.71.222

10422.828

12514.486

14582.298

16672.039

18760.6234

20850.5266

22940.6832

25020.5431

27090.283

29200.2275

Findings:

•None of the bearing freq. match.

• The harmonic freq of BPFI do not match.

•The harmonic freq. of BPFO match with the readings.

Recommendation:

The bearing outer race is in the third stage of failure and has to be replaced.

Note: harmonic means 1x(freq), 2x(freq), 3x(freq)

Conclusion:

I have been exposed to different types of rotating equipments.

I have gained good experience in analyzing the vibration readings and recommend the proper action.

I have given the opportunity to work in the Aramco Shadgham shop and dealing with different types of rotating machines during maintenance and overhauling.

I have been allowed to make studies and suggestions which improve the performance and reliability of the vibration group.