Reciprocating Compressor Performance and Safety Prediction for Control Panels
SECTION 1: Introduction
There are three general methods of modeling reciprocating compressor performance and safety prediction commonly used in unit control panel logic:
- Fast and Easy
- Covers 90% of Concerns
- Covers Everything according to the Compressor Manufacturer (OEM)
When overseeing a compressor or compressor station, one needs to know which method is being implemented in each of your control panels (UCPs). If it’s not the OEM method, then there had better be a good reason why something inferior is being used, especially if the unit is damaged due to mechanical stresses.
Before discussing various modeling methods, it is important to note that real-time modeling of performance and safety is different than real-time variable measurement, such as actual discharge temperatures and internal cylinder pressures. Real-time modeling of performance and safety allows the PLC to predict unit performance and to identify ahead of time within its defined operating map where it is safe to run that unit, but it does assume that the unit is configured properly and that it is in reasonably good health. Real-time monitoring reviews unit performance based on actual unit configuration (healthy or damaged) and operating conditions, but provides no insight on how to get out of unsafe operations other than flag alarms and shut down.
OEM Performance and Safety Prediction is required as it provides useful predictions for achieving user goals, keeping units from overloading and out of unsafe areas. Adding optional real-time monitoring can help prevent continued operations in high mechanical stress (e.g. like high rod load forces due to valve breakages from slugs of liquids). Nevertheless, even if you choose to add real-time monitoring, you still must make sure that the real-time monitoring devices are modeling your equipment in accordance with OEM modeling specifications. Without this step, inappropriate shut downs or hardware damage can still occur.