Torsional Analysis of a 20-Cylinder Hypercompressor Train

The capacity of plants for the production of low-density polyethylene is increasing worldwide and is continuing to challenge designers to provide the larger compression machinery required. The expected level of reliability and availability is very high, and the cylinders and frames of these reciprocating compressors are specially designed to withstand this heavy-duty service. All design aspects have to be properly considered, including the torsional analysis that represents a very critical element. This article considers a train with 2 compressors, each configured with 10 cylinders, with an electric motor drive between them. One machine is directly coupled to the motor while the other has a flexible coupling. This represents the largest reciprocating compressor train in the world, with a total motor power of 33 MW.