Energy companies have used supercritical CO2 in enhanced oil recovery for many decades, often with centrifugal pumps using non-contacting dry gas seals. As carbon capture and storage (CCUS) develops, new requirements emerge.
According to John Crane, since the late 1980s, users have sealed CO2 with non-contacting dry gas seals optimized for near-vapor-point liquids. A tandem, non-pressurized seal configuration is recommended for these applications, and filtering the seal flush is key to ensuring reliability.
High-speed machinery used for pipeline transport, re-injection, and carbon capture causes the temperature in the seal chamber to rise. Increasing the seal gas supply flow and cooling the supply gas (usually taken from the exhaust gas) is necessary to keep the temperature within design limits.
Atlas Copco introduced a high-pressure CO2 eight-stage compressor using non-contacting dry running gas seals, and reported that in field tests, compared to standard carbon seals, dry gas seals emitted only a fraction of the CO2.
John Crane, Pumps and Systems, Atlas Copco. The article is compiled and reinterpreted by SNS-VN; brand names belong to their owners.