ENSURING RELIABILITY OF COMPRESSOR GAS SEALS DURING LONG PERIODS OF PRESSURIZED HOLD

TutorialThis paper will discuss the challenges with contamination resulting from long periods of compressors in standstill conditions. The reliability of gas seals is largely dependent on having a continuous supply of clean and dry seal gas. In a dynamic mode the gas supply systems takes process gas from a higher pressure level in the compressor, conditions it and provides it to the gas seal to create the ideal environment for the gas seal. This ensures the gas seal is provided with effective protection against contaminated process gas. Compressor gas seals are very robust sealing devices, but need to be operated in a dry and clean environment. The leading root cause of gas seal failures is contamination. One of the most common sources of contamination is during compressor start up, slow-roll, standstill, or shutdown modes. In these modes there is a lack of seal gas flow, which suggests no means to produce seal gas flow is available, such as a high pressure gas source or booster for the seal gas supply. This is where it pays to have a reliable, clean gas supply. Without seal gas flow, sufficient seal gas cannot be provided to the gas seal and results in the gas seal being contaminated. This paper will describe contamination to the gas seal by process gas, during commissioning, by particle and by liquids, which are caused by inadequate seal gas supply. Then it will focus on different methods of providing seal gas flow during transient conditions. And finally, it will discuss solutions to ensure a reliable, clean gas flow to the seal at all relevant conditions