Vibration of Rotating Machinery in Hawiyah Gas Plant King Fahd University of Petroleum and Minerals Mechanical Engineering Departments Presented by : Ahmed Al-Jaafari Advisor : Dr. Meyasser Al-Haddad October 19,2004

Outline:  Plant Overview  Hawiyah Gas Plant Processes  Vibration Group  Case Study  Conclusion

Hawiyah Gas Plant 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: 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 POINT CONRTOL 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 ShopAreas Maintenance CrewPlanersTechnical Support Unit Quality Assurance Engineers Preventive Maintenance Vibration Group

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 minute S = speed, revolutions per second Bd = ball or roller diameter Nb = number of balls or rollers Pd = pitch diameter θ = 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 = Hz  BPFI = Hz  FTF = Hz  BSF = Hz 1. Bearing Frequency Equations: Since: S = 1800 RPM Bd = in Pd = in θ = 40 0 Nb = 12 balls  OR = 0.4 (1800/60) 12= 144 Hz  IR = 0.6 (1800/ 60) 12 = 216 Hz  FTF = 0.4 (1800/60) = 12 Hz 2. Rule of Thumb: 3. Bearing Frequency Calculator:  (BPFO) = Hz  ( BPFI) = Hz  (FTF) =12.19 Hz  (BSF) = Hz

Failure Modes: Zone AZone BZone CZone D Bearing defect frequency region Bearing component natural freq. region Spike energy Stage 1: Stage 2: Stage 3: Stage 4: X 2X 3X Random high freq. Vibration kHz

Example 1: Bearing Frequency Calculation:  (BPFO) = Hz  ( BPFI) = Hz  (FTF) =12.19 Hz  (BSF) = Hz Analysis: Findings: Non- of the bearing frequency match. Highlighted readings are the max. FequencyAccel (G-s)

Example 1: Zone AZone BZone C Findings: 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) = Hz  Outer race defect frequency (BPFO) = Hz  Cage defect frequency (FTF) = Hz  Ball spin frequency (BSF) = Hz Bearing Frequency Calculation: Analysis: Findings: side-bands freq. around the highest amplitude. the highest amplitude (prime spike vib.) = 6xBPFO

Example 2: NoBPFO harmonics 1 2xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO xBPFO Frequency Velocity in/sec 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.