How Does a Centrifugal
Compressor Work?

Centrifugal compressors, operate as dynamic compression systems, utilizing high-speed rotational energy to increase air or gas pressure. Unlike positive displacement compressors, which trap and compress a fixed volume of air, centrifugal compressors achieve compression through continuous acceleration and deceleration of airflow.

This method enables high-flow, steady-state operation, making centrifugal compressors essential in industries requiring large volumes of compressed air at stable discharge pressures. Common applications include oil and gas processing, petrochemicals, power generation, and electronics manufacturing, where high-efficiency, oil-free air is critical.

Centrifugal Compressor Animation

Watch an FS-Elliott air compressor in action as the air travels through each stage of the process, resulting in a reliable, ISO 8573-1 Class 0 oil-free air stream to power a variety of industrial applications. 

The Operating Principle of a Centrifugal Compressor

1. Air Intake – Ambient air enters the compressor through the inlet guide vanes and is directed toward the center of the impeller, a rapidly rotating disk with radial blades.
2. Velocity Increase – As the impeller spins, it forces air outward at high velocity, increasing kinetic energy.
3. Pressure Conversion – The air then passes through the diffuser, where velocity decreases, converting kinetic energy into pressure energy before discharge.

Key Components of a Centrifugal Compressor

• Impeller – Equipped with radial blades, the impeller spins at high speeds—often exceeding 50,000 RPM—to accelerate air outward, increasing its velocity. Constructed from high-strength alloys, impellers are designed to endure extreme rotational forces for lasting durability.
• Diffuser – As air exits the impeller, it enters the diffuser, a stationary component that slows airflow and increases pressure. This stage efficiently converts kinetic energy into static pressure.
• Casing – The casing encloses and protects internal components while guiding airflow through each stage. It is engineered to withstand high pressures and temperatures and ensures structural integrity for safe operation.
• Inlet Guide Vanes (IGVs) – IGVs control airflow entering the impeller, optimizing efficiency under varying load conditions. Adjustable IGVs improve part-load performance and reduce power consumption when full capacity isn’t needed.
• Collector (Volute or Scroll) – The collector gathers compressed air from the diffuser and channels it toward the discharge outlet. Single-stage compressors often use a volute chamber, while multi-stage models utilize manifolds to balance airflow.
• Coolers – Critical for maintaining efficiency, coolers reduce compressed air temperature before the next stage or final discharge. Intercoolers lower air temperature between stages to improve density and reduce compression effort, while aftercoolers cool discharged air to prevent excess heat from reaching downstream equipment and assist with moisture removal.

Advantages of Centrifugal Compressors

• High Flow Capacity – Engineered to handle large volumes of air or gas, making them ideal for industrial-scale operations.
• Energy Efficiency & Low Maintenance – Unlike reciprocating compressors, centrifugal compressors have fewer moving parts, reducing frictional losses and maintenance requirements.
• Certified ISO 8573-1 Class 0 Oil-Free Operation – Many centrifugal compressors utilize air or magnetic bearings, eliminating the need for oil lubrication and ensuring contaminant-free air.
• Steady Pressure Output – Designed for applications requiring constant air pressure without pulsations, such as power plants and chemical processing facilities.
• Unmatched Reliability – The modular airend design allows for easier maintenance and faster repairs, whereas rotary compressors, due to their complex components, often require more extensive downtime. 

Industrial Applications of Centrifugal Compressors

• Oil Refining – Used in hydrocracking and catalytic reforming processes to compress hydrogen and other process gases.
• LNG Production & Transport – Critical for gas liquefaction and transportation, ensuring efficient natural gas handling.
• Petrochemical – Supports ethylene and propylene production by compressing process gases in large-scale chemical reactions.

• Chemical Processing – Essential for providing compressed air and gas in industrial chemical synthesis and reactions.
• Air Separation Units – Used in the production of industrial gases like oxygen and nitrogen for manufacturing applications.
• Plastics – Integral to polymerization and extrusion processes where compressed air is needed for forming and shaping.
• Glass – Supports high-temperature furnace operations and precision forming processes.
• Steel – Plays a role in blast furnace operations and pneumatic conveying of materials in steel production.

• Electronics – Provides clean, oil-free compressed air for semiconductor and circuit board manufacturing.
• Electric Car & Battery Production – Used in lithium-ion battery production and cathode/anode material processing.
• Industrial Manufacturing – Supports automation systems, pneumatic tools, and assembly line operations requiring precision airflow.

• Power Generation – Integral to gas turbines in power plants, supplying combustion air for efficient energy production.

• Food & Beverage – Ensures hygienic compressed air for bottling, packaging, and food processing applications.
• Medical & Pharmaceutical – Used in sterile air supply, vacuum packaging, and medicine production requiring contamination-free environments.
• Pulp & Paper – Supports drying processes, pneumatic material handling, and wastewater treatment in paper production.
• Textiles – Provides compressed air for weaving, dyeing, and fabric finishing operations.

Enhancing Centrifugal Compressor Performance

• Monitor Inlet Conditions: Ensuring incoming air is free from contaminants prevents fouling and extends component life.
• Regular Inspection of Bearings and Seals: Routine checks and maintenance of these elements are crucial to prevent mechanical failures and sustain efficiency.
• Optimize Load Conditions: Operating compressors within their designated capacity range promote energy-efficient performance.
• Proactive Maintenance & Performance Optimization: Establish a comprehensive maintenance plan by following scheduled maintenance guidelines from the OEM, incorporating remote monitoring, and utilizing energy advisory features to optimize efficiency and identify areas for cost savings.