2,050 m³/min Centralised Air Supply Station for a Steel Mill in Zhejiang

A long-established steel mill in Ningbo, Zhejiang Province, depends on compressed air across its production lines. Its two compressor stations were old and energy-intensive, and high moisture content in the air from the southern station was affecting downstream processes. Compressed air is one of the largest energy consumers in a steel works, so the stations offered significant savings potential.

The mill decided to consolidate its supply into a smart, centralised air station. The station was financed, built and operated by a local energy-services company under a long-term air-supply arrangement.

The project was carried out in two phases:

• Phase I: a new northern compressor station. It applied integrated water and air regulation, condensate recovery and main-header flow distribution, and went into operation first.
• Phase II: a complete renovation of the southern station, built around six SIND TurboPure MT series centrifugal compressors: four larger and two smaller units.

Phase II also added heat-of-compression dryers, aftercoolers and air receivers. These solved the moisture problem and improved supply stability. A station-wide monitoring and control platform provides remote monitoring, automated control and fault warnings for all compressors.

The station was inspected by an independent national testing institute and met the Grade-1 energy-efficiency standard.

With both phases in operation, the central station delivers:

• 2,050 m³/min total supply capacity.
• More than 603 million m³ of compressed air per year.
• About 18 million kWh of electricity saved per year, an energy saving of about 20%.
• About CN¥11.8 million (≈US$1.66 million at CN¥7.1/US$) lower operating cost per year.
• About 10,270 t lower CO₂ emissions per year.
• Drier, more stable air for downstream production.

Large centrifugal compressors combined with heat-of-compression drying and central control give steel mills a high-capacity, low-cost air supply.