(155e) Full Machine Electrification of a Grass Roots Ethylene Plant

Traditionally, large compressors in ethylene plants are driven by steam turbines which are fed by steam generated in conventional cracking furnaces as well as auxiliary boilers. In future low-emission olefin plant designs, significantly reduced generation of waste heat carriers such as steam from the furnaces is targeted. Accordingly, reduction of steam consumption in the separation section will play a key role in holistic low-emission plant designs.

In a recent grass roots ethylene plant design, Linde Engineering has electrified the drive trains of all large compressors - Cracked Gas, C2 Refrigerant and C3 Refrigerant Compressors.

The full machine electrification step was a key element to achieve a substantial CO2 emission reduction and an increased energy efficiency.

Due to the required shaft power and speed range of the cracked gas compressor and the lack of as-built references for this particular combination of shaft power versus speed, specific taylor - made process and electrical solutions were created by smart and innovative process and electrical design.

In this paper, the authors will take a detailed look at the process solutions applied for this specific grass roots ethylene plant with its unique constraints and explain the selected electrical drive concept with its advantages. The paper will also compare a conventional steam turbine drive solution with the chosen electrical drive solution from a reliability, availability and maintainability (RAM) point of view highlighting surprising advantages from the selected electrification concept.