• Design a compact, light-weight solution tailored for load issues of a North Sea platform
  • Sour gas operation with H₂S up to 1,800 ppm
  • Customize an active magnetic bearing (AMB) configuration to enhance machine reliability
  • Oil-free configuration with AMB maintains weight under specified limit and minimizes footprint
  • Dry gas seals ensure safe operation in sour service
  • Complete in-house assembly and testing, including ABM tuning in collaboration with SKF

Case study details

Natural gas liquid (NGL) applications require expander-compressors that can work in cryogenic conditions while separating natural gas from liquid. At discharge, our expander-compressors can manage up to 35% liquid content of the total flow. Their lightweight and compact structures are ideal for overcoming platform load issues.

In 2019, Baker Hughes supplied the Tyra project with seven centrifugal compressor trains driven by electric motors, and two expander-compressor packages for NGL service. To keep the overall package compact and light, an oil free configuration was needed. Thanks to our partnership with SKF, we have enhanced in-house capabilities for tuning active magnetic bearings (ABMs) and integration with our standard product portfolio—providing solutions for the most demanding projects. The AMBs can reach peripheral speeds up to 145 m/s.

The project was also challenging because of high H2S content in the flow, which exceeds 1,800 ppm, and creates an environment typically not suitable for AMB. To ensure oil-free configuration, we deviated from the standard package and installed dry-gas seals. Both packages were assembled and successfully testing at our Florence facility. Installation and first start-up are expected in early 2021.

Our expander-compressor trains will process more than 147,000 kg/h of natural gas in cryogenic condition (-12°C at discharge). This will increase platform productivity and make NGLs available as petrochemical feedstock for various chemical-based products that will enable additional value streams for the customer.


H2S content
1,800 ppm
Inlet pressure
63 barA
Outlet pressure
51 barA
750 kW


Compact, lightweight, oil-free expander-compressors for North Sea platform 1
Compressor impeller detail during assembly.


Compact, lightweight, oil-free expander-compressors for North Sea platform 2
Turboexpander compressor package fully assembled at Florence facility ready for testing.