Abstract

Methane’s high global warming potential, approximately 29.8 times that of CO₂ on a 100-year basis, combined with its relatively short atmospheric lifetime, makes its reduction one of the most effective near-term strategies for mitigating climate change. Compressor stations, which play a key role in gas transportation and storage, are responsible for part of these.

The main sources of compressors emissions are seal leaks and blowdown events occurring during maintenance activities.

We are then presenting a recovery system designed to minimize hydrocarbon losses from these sources, applicable to both existing assets and new installations, based on an auxiliary system that can be used both for vent recovery and to recompress trapped gas during shutdowns, reducing atmospheric releases.

  • Seal vent and blowdown recovery systems applied to centrifugal and reciprocating compressors directly target avoidable operational emissions.
  • Recovery solutions transform emissions into recoverable product, contributing to sustainability and emissions‑reduction objectives.

Then, Gas Recovery Package Unit (GRPU) is designed to:

  • Re-pump leakages
    • In particular, for centrifugal compressors, re-pump the Dry Gas Seals leakage vent (DGS Vent recovery)
    • Depressurized the centrifugal compressor loop (Blowdown)

This service is typically performed using auxiliary compressor skids, with reciprocating piston compressors (commonly referred to as reciprocating compressors) and such solution is commonly selected by many manufacturers and OEMs; see for example Figure 1. These auxiliary units, however, are subject to inherent leakage characteristics typical of reciprocating compressor technology.

The proposed solution is about using a diaphragm compressor as an auxiliary compressor for the recovery system, or a hybrid compressor consisting of stages with both reciprocating piston and diaphragm compressors, Figure 2.

This solution will give as main benefits

  • Increased compactness and simplification, thanks to the lower number of cylinders needed to perform the compression
  • Diaphragm based architecture is a zero leakage
    • This technology is a real zero emission solution, as it is used to deal with toxic and radioactive gases too
    • Methane GWP is 25-28, thus meaning that 1 CH4 ton à 25-28 tons CO₂e. Hence this further leakage reduction represents a strong GWP reduction

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Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

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