API 618 Pulsation Analysis

Acoustical Pulsations and Mechanical Vibration Analysis – API618 M2-M11

Acoustical analysis focuses on reducing pulsations in the compressor manifold system, therefore reducing dynamic forces acting on the mechanical components.

The mechanical analysis includes the calculation of the mechanical natural frequencies (MNFs) and the modal shapes and the force response analysis of the compressor body, heads, bottles, vessels and connecting piping system and their connections to the skid.

The pulsation induced shaking forces as well as the static pressure-induced forces are applied to the shell and internals of the Pulsation Suppressor internals. The resulting stress levels are computed so that they are below the failure limit of the material and the geometry.

The stresses induced on the pressure vessel/pulsation bottle by thermal gradients, thermal transients and pressure cycles, including nozzle loads imposed by the piping system, are calculated and compared to allowable levels for the required number of pressurization/heating cycles during the equipment’s useful life.

• Detailed report including a description of the recommended changes to (size and location of orifice plates, bottle size and internals, changes in piping layout, etc.) that will make the system API618 compliant.
• Detailed report on peak pulsation levels, peak shaking forces, pressure drops and power losses before and after the recommendations.
• A detailed schedule of required design changes clamps locations and additional supports necessary to reduce vibration and stresses to allowable levels. Lists of significant MNFs, modal shapes, vibration levels and stresses are also reported for all critical points in the model
• Static and dynamic stress levels are presented as well as design changes that may be necessary to reduce such stresses to allowable levels.
• Stress levels and code compliance are reported for all conditions and all critical points. Recommendations for design changes are made if necessary.

Information needed to conduct an API 618 Acoustical