Compressors in High Pressure Pipeline Applications

While typical gas transmission pipelines operate at pressures up to about 100bar, a number of applications in North America and Australia use or are planning pipelines operating at significantly higher pressures. Often, these operations are referred to as ‘dense phase’. Several existing installations are described and analyzed. We will explain the underlying reasons why higher pressure pipelines are considered, as well as the trade-offs compared to traditional, lower pressure pipelines. A parametric study is presented to evaluate the impact of higher operating pressures on the net present value. The impact of a larger effort to bring the gas to the higher pressure is discussed. Since some of the pipelines are designed to transport CO₂, the particulars of high pressure CO₂ transport are highlighted. The impact on compressor and driver selections is also considered, in particular the impact of the higher power density of the centrifugal compressors at higher pressures.