How do dry gas seals work in centrifugal compressors and what are the operating concerns?

Dry gas seals use a thin gas film (microns) between rotating and stationary faces, created by spiral grooves that pump gas inward. Advantages over wet seals: no oil contamination, lower power loss, higher reliability. Operating concerns: clean dry seal gas essential (filtration, conditioning), proper pressure control for seal gas supply, monitoring seal vent flows (primary, secondary, tertiary), and temperature monitoring. Tandem seal arrangement provides backup. Contamination or loss of seal gas causes rapid failure. Proper commissioning and operating procedures critical.