Our work

Pulsation analysis according to API 618 and API 674

Reciprocating compressors and pumps are frequently used in many applications. They generate pulsations that can cause a number of problems, such as severe vibration, fatigue failures, reduction in efficiency, hammering of valves and errors in flow measurement. To prevent problems during operation, installations must undergo an integrated design analysis according to API 618 standard (compressors) or API 674 (pumps).

Over 40 years, TNO has built up an impressive track record in design evaluation and trouble shooting projects for reciprocating fluid machinery. We developed our simulation software Pulsim, which set the standard in pulsation analysis. Our portfolio includes all items as required by the various design approaches in API 618 and 674. This includes pulsation analysis, mechanical response analysis, compressor valve dynamic analysis, compressor manifold analysis etcetera. In addition, we have a large experience in other relevant simulation techniques, such as piping flexibility analysis and torsional analysis. As an independent party we often review studies performed by other parties.

Typical steps in API analysis

  • Step 1 - Check of the pulsation damper design A good design of the pulsation dampers is essential for each system. Each project starts with an evaluation and optimization of the dampers. This step is typically performed in an early stage of the project within a few weeks.
  • Step 2 - Pulsation analysis of the piping This step involves the modelling of the complete pipe system, including all relevant equipment, such as valves, heat exchangers, separators, mixing points, flow meters etcetera. The pulsations and pulsation-induced shaking forces are calculated and compared with allowable levels. In case of exceeding we optimize the design in close cooperation with the client.
  • Step 3 - Mechanical response study Even if the pulsations are within allowable levels, unallowable vibration and cyclic stress levels may occur due to excitation of mechanical resonances. Therefore, we ensure allowable vibrations and stresses by adequate supporting design.

Integral consultancy

Besides the design evaluation according to API 618 and 674 standards, we provide a large range of consultancy services. We provide prompt assistance in trouble shooting projects. We have a large practical experience and database from field measurements, both onshore and offshore. Project communication and reporting can be in English, German, French, Spanish and Dutch. Our expertise also includes other relevant phenomena in process installations, such as interaction with turbomachinery, water hammer, multi-phase flow excitation etcetera. Finally, our software tools are integrated in PulsimSuite, which can be purchased or leased commercially.

ECN part of TNO

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