API Standard 674 specifies the requirements for the pulsation study. This is recommended for many pump applications. Plunger pumps (also called diaphragm pumps, positive displacement pumps, or reciprocating pumps) are used in many applications, including petroleum production facilities and refineries. A pulsation and mechanical vibration study is often necessary for new or modified plunger pumps to avoid these typical problems: - excessive piping vibration and piping failures;
- pressure pulsation-induced cavitation in liquid pump fluid ends and suction manifolds, damaging the pump and reducing reliability;
- undesired opening of PSV due to pulsations; and
- improper pump valve dynamics.
Scope - Assess the magnitude of pressure pulsations and unbalanced shaking forces
- Recommend a pulsation solution that meets API 674 guidelines and BETA guidelines
- Conduct a mechanical analysis of the piping layout and support using standard tables and spreadsheet calculation
- An optional finite element mechanical analysis of the piping system can be conducted to avoid coincidence between mechanical natural frequencies (MNFs) and dynamic forces occurring at multiples of plunger passing frequency.
Application Guide - This simple guide is useful to determine the pulsation study scope and other application requirements.
- Contact BETA for other application questions, including Valve Dynamic Assessments and troubleshooting.
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| | Features of BETA's Pulsation Studies - Assessment of pressure pulsations and unbalanced shaking forces
- Recommended pulsation control solutions
- Assessment of static and total pressure drop, and compare to guideline
- Assessment of all operating conditions
- Use of BETA’s time domain software to accurately calculate pressure pulsations through the system
- The following considerations must be evaluated for improved reliability:
- Cavitation inside pump chambers and in suction lines
- Pressure and vibration at relief valves (per guidelines)
- Pipe stresses
- Upset conditions (e.g., plunger valve failure)
- Optional: Detailed mechanical analysis of the system to avoid high vibration due to resonance, normal shaking forces, and forces produced in upset conditions
Limitations - The analysis does not assess vibration in the skid and/or foundation. These assessments are provided by separate analyses.
- The standard analysis considers pulsation and vibration up to 150 Hz. High order pump manifold acoustic resonances and shell mode vibration in piping and vessels are outside the scope of this analysis.
| | - Off-skid piping will be included when the required information is available during the start of an analysis. If the off-skid information is not available during the course of the on-skid pulsation (acoustical) analysis we will use our proprietary method for performing a sensitivity analysis of the on-skid components to the interactions from off-skid components. BETA can revisit its work if off-skid details are made available after the study is completed (additional scope).
Customer Benefits - Cost effective solution to avoid pulsation related problems
- Improved reliability, availability, efficiency and safety by avoiding piping and vessel vibration failures
- Reduced maintenance and operating costs
Advantages
BETA is the global leader in pulsation analysis because of these factors: - Responsive application advice and ongoing customer service
- Most advanced acoustical/mechanical modeling software on the market
- Timely recommendations
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