Optimizing compressor packing designs by predicting rod temperatures.

Abstract

The pressure packing is a critical component of every reciprocating compressor. High wear leads to increased process gas leakage rates which can result in a compressor shutdown. Excessive leakage can even cause fugitive emissions if the emission control system is not set up for high leakage levels. These fugitive emissions can cause environmental concerns, safety issues in case of hazardous gases and it can lead to reliability problems if the crank case is contaminated with process gas. High pressure applications, non-lube machines or abrasive environments are especially prone to high wear rates and increased packing leakage rates. Current packing engineering standards rely on rule of thumb methods and selection tables. This lecture presents a method to maximize the packing run time by optimizing the performance determining parameters of the packing. By predicting the rod temperature distribution, the performance of different packing layouts can be compared and relative run time prediction can be given. The lecture describes the model details, discusses the heat transfer correlation assumptions and deducts general packing design guidelines based on the model results. Several packing optimizations have been performed using this approach and two case studies are discussed in this lecture.