Siemens STC-SX Compressor Series

Innovative and Reliable

The Siemens STC-SX compressor type is optimally featured for today’s blast furnace requirements – which are characterized by the continuous strive for larger compressor units with increased efficiencies. Siemens axial flow compressors STC-SX have proven to meet customer needs: designed to handle large volume air flows and other clean gases within relatively small casings while maintaining excellent efficiency. Since 1950, the concept of Siemens STC-SX has continuously been optimized. Designed in accordance with API 617, this product line now allows for volume flow rates up to 1,300,000 m³/h.


  • The perfect match for large volume flows
  • Excellent efficiency
  • Low maintenance costs


  • Blast furnace air
  • FCC air

Design Concept

High Flow Rates at High Efficiencies

Designed for large volume air flows and other clean gases within small casings, Siemens STC-SX compressor series guarantee excellent efficiency. Fulfilling highest technical standards, the compressor design is according to API 617.

Casings have an axial or radial inlet. As standard, they are fabricated. On special request, Siemens also offers cast casings. These machines are typically uncooled straight-through compressors, optimal for high discharge temperatures.

Modular Principle

The design principle common to the Siemens STC-SX series is a modular concept. It is based on finely graded machine elements and flow components that have proven their reliability over many years of operation.


  • Tilting pad bearing for journal and axial thrust bearing
  • Up to 19 stages
  • Outstanding blading technology
  • Rotor blades of first and second stage are made of duplex steel
  • Corrosion resistance due to unique material usage

Control Systems

  • Broad range of appropriate control systems
    • Performance control
    • Independent anti-surge protection
    • Anti-choke control
  • Control by either speed variation or adjustable guide vanes, or a combination of both

Technical Data

  • Flow rates from 50,000 to 1,300,000 m³/h (30,000 to 825,000 cfm)
  • Pressure ratio between 1.9 and 6.0
  • Speed up to 9,000 rpm
  • Discharge temperature up to 350°C
  • Various control systems to optimize operation
  • Driver: electric motor or steam turbine, depending on process and energy resources


Combining reliable technology with innovative development, Siemens STC-SX axial flow compressors guarantee the following benefits to optimize your business:

  • Compression of large volume flows within relatively small casings
  • Highest degree of efficiency
  • Extended operating range
  • Modular and robust machine design
  • High quality due to proven components and API standards
  • Prevention of wear due to optimized material selection
  • Low operating and maintenance costs