The economic success of a gas compression operation depends to a significant extent on the operation and selection of the compressors involved. Important criteria include first cost, operating cost (especially fuel cost and maintenance cost), life cycle cost, availability, flexibility and emissions. Decisions about the layout of compressor stations such as the number of units, standby requirements, type of driver, and type of compressors have an impact on these criteria. The operating conditions of the station are dictated by pipeline hydraulics and demand profiles as well as ambient conditions. Therefore, any station evaluation has to take the hydraulic behavior of the pipeline into account, which determines the relationship between flow and pressure, and thus the operating conditions for the compressor.
This paper discusses issues that influence the decision on the arrangement of compressors and the type of equipment in gas pipeline compressor stations. Different concepts such as multiple units versus single units are considered, both regarding their impact on the individual station and the overall pipeline. The necessity of standby units is addressed.
The importance of considering all possible operating conditions as a result of studying the pipeline behavior via pipeline hydraulic simulations is stressed, and examples are given. With the wide range of possible operating conditions for the pipeline in mind, the discussion will be brought into the general context of operational flexibility, availability, reliability, fuel consumption, emissions, installation issues, remote control, and operability.