The production of LDPE may require huge heavy-duty reciprocating compressors to withstand the loads, deriving from the operating pressures, to satisfy the growing needs of the market. Safety, Performance and Reliability are normal expectations and therefore need a thorough evaluation of the specific service. The machine selection is based on positive experience in similar applications and cylinder performance. The cylinders are special pressure vessels, whose design and construction have to consider the extreme internal pressures and the process gas. The design must foresee all possible failure modes of each component, to have safe and smooth operation, thanks to innovative methods of modeling and simulation, like FEM and CFD, important for the design of cylinder parts.
Valves are simulated by mathematical models optimizing performance, to reach a correct mechanical behavior with minimum energy consumption and ensuring reliable operation.
The available technological improvements are a starting point, resulting from the developments of manufacturers and long experience of End Users.
The pulsation and vibration of the piping are usually investigated to keep the plant in operation without failures.
Many cylinder components are exposed to pressures fluctuating between suction and discharge and therefore to high fatigue loads. To reach high endurance capabilities they have to be pre-compressed to keep them operating under compressive stresses whenever possible. Special materials, shrink fitting and auto-frettage procedures are usually required.
The operation is the stage where all the parameters have to be kept under control and incipient problems have to be identified to minimize shut-downs and arrange various maintenance works. Automation, monitoring and diagnostic systems complete the efforts of operators to afford high safety levels, with increased availability and optimized maintenance interventions.
The continuing development of technology will help to challenge performance and high capacity demand of future plants.