Seal Gas Recovery Systems 101: What You Should Know

November 24, 2022 | 3 minute read

Aerial view of factories


With changes to emission regulations regarding gas flaring and venting, companies are seeking a cost-effective solution to capture vented process gas for recovery and achieve greenhouse gas (GHG) reduction targets. Companies can utilize a Seal Gas Recovery (SGR) system as the technical solution for their dry gas seal vent recovery needs, achieving zero-emissions operations while reducing capital requirements.

The inner workings of an SGR system

Here’s how an SGR system works. It pairs with an existing tandem dry gas seal, connecting to the primary vent system to recover and pressurize the vent gas. A gas ejector uses a high-pressure stream to entrain and pressurize the primary vent leakage. The pressurized gas is conveyed to another useful location in the customer’s operation, including:

  • The suction line of another compressor
  • Fuel gas header
  • Another gas seal support system

The ejector is a static piece of equipment and contains no moving parts. This results in the following:

  • No net increase in the overall energy use of the system
  • Minimal maintenance requirements

Seal Gas Recovery systems are suitable for applications such as natural gas pipelines as well as propylene and ethylene compressors.

Economic and environmental benefits

An SGR system can address the need for companies to comply with zero-emissions environmental regulations while providing cost savings in the form of recovered process gas. The valuable process gas that would otherwise be disposed of can now be diverted to more productive purposes to reduce product loss.

SGR systems also provide users with a solution to comply with increasingly strict environmental and emissions regulations regarding gas flaring and venting. It allows customers to utilize dry gas seals to achieve zero-emission operations and reduce capital requirements. We’ve run the numbers:

  • Operators of an average natural gas compressor could see yearly savings greater than $193k* (£162k)
  • Operators of propane, ethylene and other refined gases could see yearly savings greater than $119k* (£100k)

Partner with SGR system experts

John Crane has experience in this area for over 100 years. Learn more about how our SGR system can offer economic and environmental benefits.

*Based on August 2022 cost of natural gas, £7.5/MMBtu ($9.00/MMBtu).
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