TABLE OF CONTENTS The compressor operator must provide a source of separation gas supply to the compressor gas seal system. The separation gas is required for the barrier seals, which are intended to prohibit lube oil migration into the gas seal. The separation gas is usually provided to the barrier seals through stainless steel tubing. Like the primary seal gas, the separation gas must be available at sufficient pressure, as defined by the barrier seal manufacturer, with enough safety margin to account for buildup of pressure drop through the gas seal system components. It is very common to use plant instrument air as the separation gas medium. This requires careful attention to safety considerations, which is discussed later. It is highly preferable to use a nitrogen source for separation gas.
Compared to the main seal gas supply, the quality and composition of the separation gas is of lesser concern. The manufacturer's gas quality requirements for barrier seals are less stringent than for dry gas seals. The typical sources of separation gas (nitrogen or instrument air) are generally very clean in comparison to seal gas sources. Therefore, a typical separation gas quality requirement at the customer connection point on the gas seal system is that it be free of solid particles 5 ?m and larger and 99.97% liquid free.
Separation gas filters are usually provided immediately following the customer connection point on the gas seal system. These filters are designed as final or last-chance...
