Conversion Of A 19,000 HP Propylene Compressor Drive From Steam Turbine To Electric Motor With Geared Cariable Speed Turbo Coupling.

Abstract

In the course of modernizing an ethylene plant in 1985, Union Rheinische Braunkohlen Kraftstoff AG converted a propylene compressor with 4 process stages from a steam turbine drive to an electric motor drive. The economic objective of the conversion was to reduce the required high-pressure steam flowrate, e.g., initiated by converting from light to heavy feedstock. Speed control of the compressor was to be maintained, since conversion to another control system with constant speed would have been very difficult with the existing compressor. The decision between electrical variable speed motor and electric motor with geared variable speed turbo coupling was made in favor of the motor with geared variable speed turbo coupling type. It was necessary to extend the foundation itself, due to the greater overall length of the drive unit (geared variable speed turbo coupling/electric motor) compared to the steam turbine. Additionally, the platform was extended and supported. The geared variable speed turbo coupling and the electric motor were mounted on a common frame designed specifically to be particularly rigid. The variable speed fluid coupling operating on the hydrodynamic principle was incorporated in a common housing together with its gear stages. Available time: three months during a scheduled shutdown. No problems occurred during installation and commissioning. The process control system operated satisfactorily; all mechanical, electrical limit values and values relative to vibration were met with a safe margin.