CobaDGS: The First Zero-Emissions Compressor Seal

CobaDGS  from EagleBurgmann is the first gas-lubricated compressor seal eliminating climate-critical methane leakage. It is a nitrogen-supplied high-pressure unique dry gas seal designed to meet compressor operating conditions used by gas network operators. When a nitrogen generation unit is included to support the seals, it eliminates nitrogen transportation costs for supporting it.

Previously, zero-methane gas emissions were only achievable with gas-lubricated compressor seals when operated at a low pressure and speed. The newly developed CobaDGS overcomes this dilemma and delivers higher safety and increased reliability.  Incorporating this solution at natural gas compressor stations eliminates nearly all methane emissions. In most cases, the compact seal design requires no compressor housing modifications. It is an ideal seal for upgrading single, tandem, or double dry gas seals, as well as, upgrading oil seals.

Greater security, less maintenance

With the addition of a typical dry gas seal to back up the CobaDGS, safety is added should unforeseen events cause a CobaDGS failure. Since the CobaDGS is continuously supplied with clean, dry nitrogen rather than process gas, this eliminates failures that would occur with a typical dry gas seal when not supplied with properly conditions seal gas. With the clean, dry nitrogen supply and unique design this seal provides an unequalled safety and seal reliability. This prevents unnecessary compressor venting from a seal failure and reduces seal maintenance efforts. The seal design handles operating pressures to 160 bar, supporting most operating conditions associated with tandem seals. In the event the nitrogen supply is lost, the seal continues functioning safely and robustly with process gas. This eliminates the need to stop and vent the compressor and allows time for the nitrogen supply to be restored without concern of a seal failure. 

High-pressure on-site nitrogen generator

In addition to the seal, EagleBurgmann supplies an optimally designed on-site generation system to produce the nitrogen supply. The nitrogen is extracted from air via a pressure swing adsorption process at a 6-bar operating pressure. This is then compressed and stored at 330 bar pressure and dynamically adjusted to the required pressure level, which is 0.5 bar above the sealing pressure. 

The CobaDGS solution for eliminating compressor seal emissions has lower secondary emissions associated with it, delivers a higher and proven seal reliability, and has lower maintenance requirements compared to other systems, which recompressing seal leakage for natural gas pipeline compressors. A pilot project incorporating the CobaDGS and nitrogen generation system has been in operation since mid-October 2020 at a France compressor station supporting how effective this new and unique seal solution eliminates climate changing methane seal leakage and compressor venting.
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