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Design Approach 2 / 3 stage / Parallel operation / 300rpm / Revamping / 3300kW
Acoustic, Vibration, API 618, API 688, Design approach 2, Reciprocating Compressor
Three (3) stage reciprocating compressors has been running for 25 years, since these compressors had been initially commissioned after construction. With consideration of improved process demand, it was necessary to revamp the process and pipe condition for these compressors, and this was due to perform new pulsation study. This pulsation study was performed as per Design Approach 3 procedure in accordance with API 618, API 688, and this page shares the analysis status of Design approach 2.
Contents
- Scope of this analysis
- Pulsation for Existing condition
- Vibration Survey
- Case Study
- Pulsation Amplitude
1. Scope of this analysis
The scope of service for this pulsation study as Design approach 2 below activities;
- Review for Existing Pulsation Study
- Acoustic Modeling
- Vibration Site Survey
- Case Study as per Cylinder Phase Difference
- Design Approach 1, Surge Volume Sizing as per API 618
- Design Approach 2 for Acoustic Simulation
- Pulsation Limit & Criteria Assessment
- Pressure Drop by Surge Volume and Orifice


2. Pulsation for Existing condition
Pulsation study for existing condition was carried out, so that we can confirm if there is no design issue with high pulsation amplitude.
- Review the previous pulsation study
- To check the design reliability for pulsation control device
- To check if the pulsation level by existing condition is complied with API 618
- For suction, inter-stage, discharge piping system
- Review the compressor operation data for Existing and Revamping condition

3. Site Vibration Survey
Vibration survey and measurement was done at Site, and INERTANCE engineers checked if there was no high vibration issue for piping system with existing condition. And, the measured vibration levels were compared with related vibration criteria such as EFRC (European Forum for Reciprocating Compressors), ISO 10816-8 and Wachel chart, etc.
- Measurement for pipe vibration
- Vibration check for Crank case, Cylinder flange, Pulsation bottle, Piping system, etc.
- Assessment for vibration criteria listed in below
- EFRC (European Forum for Reciprocating Compressors)
- ISO 10816-8
- Wachel chart



4. Case Study – compressor pulsation study
When these compressors are to be operated in conjunction with other compressor units and their associated piping system, the additive effect of pressure pulsations from multiple units shall be addressed. It was planned to run these compressors with parallel operation, hence, Case study was necessary to find out the worst case scenario as per each compressor cylinder phase difference.
- Possible operation case to be checked
- Step operation for reciprocating compressor (25%, 50%, 75%, 100%)
- Single acting (SA) and Double acting (DA) operation
- Cylinder phase difference for parallel operation
- Multiple unit additive effects
- Start-up operation with Nitrogen gas

5. Pulsation Amplitude
Design approach 2 was to perform the acoustic simulation and piping restraint analysis, which include the pulsation control design via the use of pulsation suppression devices and proven acoustic techniques.
- Pulsation control device design
- Surge volume, Pulsation bottle, Pulsation suppression device
- Orifice at compressor cylinder flange
- Pipe support span table for separation margin
- Pulsation induced shaking force
- Shaking force assessment and criteria by API 618
- Pulsation at cylinder flange, Surge volume and piping system

6. Relates Services
INERTANCE has a full capability regarding related noise and vibration engineering as listed in below.
Please feel free contact us at (admin@inertance.com).
- Acoustic Induced Vibration (AIV) Study
- Flow Induced Vibration (FIV) Study
- Pulsation Study for Reciprocating Pump
- Surge Analysis (Water Hammer)
- Torsional Vibration Analysis
7. Key Words
- Reciprocating Compressor
- Pulsation
- Acoustic
- API 618, API 688
- Vibration measurement, survey
- Surge Volume, Orifice
- Shaking Force
- Vibration
- Compressor pulsation study
- pulsation study
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