Vibrations – but no access to the plant?
In the present case “dancing cooler racks” in a LDPE plant were the reason for the operator to call KÖTTER Consulting Engineers for a vibration analyze. However, The piping system of such a plant is set up in an EX-rated environment inside of a bunker, which is normally prohibited to enter during operation.
Therefore, vibration issues are often tackled with either simplified spot measurements at distinct locations or extremely complex and expensive measurement setups. Nevertheless, it is more or less impossible to get a full picture including operational deflection shapes as well as reliable and comprehensive assessments.
Measurement from a safe position with precise results.
To overcome this, we carried out the vibration measurement by means of a laser. The main advantage of this technique is the possibility to acquire mechanical vibrations at almost every object in the line of sight of the sensor from a safe, non-EX zone far from outside of the bunker. An additional advantage is, that the method is almost independent from the surface temperature.
Result & Lessons Learned
Based on the results, it was decided in this case to increase the stiffness of the racks by installation of additional beams. The vibration level at the rack was decreased to 30 % of the original value. The pulsations at the discharge flanges of the compressor and close to the reactor bay were within the limits defined by the original pulsation study.
When the access to certain areas in a plant is restricted or even forbitten (ex-zones, too high temperatures, too high buildings etc.) KCE provides technical solutions to overcome these obstacles.