Centrifugal Compressors – Everything You Need to Know

What is a Centrifugal Compressor?

A centrifugal compressor is a type of impeller compressor that increases the pressure of a gas by imparting kinetic energy through a high-speed impeller and then converting it into pressure energy in a diffuser and direct system. Unlike positive displacement compressors, it relies on centrifugal force, making it ideal for industries and applications that require a large supply of compressed air.

These multi-stage centrifugal compressors are key in power generation, gas processing, and HVAC. They offer completely oil-free air with low maintenance and high efficiency. Compared to axial compressors, centrifugal models provide stable airflow with less wear and tear, making them a cost-effective solution for applications that require consistent high-pressure air delivery.

By efficiently converting the kinetic energy of the air, centrifugal compressors ensure reliable performance across industries and applications that require large-scale air compression.

How Does a Centrifugal Compressor Work?

According to Bernoulli’s principle, a centrifugal air compressor uses the air’s kinetic energy to produce a pressure rise. The air enters the centrifugal compressor impeller, where the impeller blades accelerate the air tangentially, creating high velocity.

The local spinning velocity X the local impeller tangential velocity = the energy imparted to the air.

The output flow leaving the centrifugal impeller goes into a compressor diffuser, where the air velocity decreases, and kinetic energy is converted into pressure energy. This increases the diffuser’s pressure to get the desired gas pressure.

Multistage compressors use additional centrifugal compressor stages to achieve further pressure. These are commonly horizontally split or integrally geared centrifugal designs, which offer flexibility and efficiency, especially in high-demand applications like gas turbine performance, power generation, and industrial processes that require higher flow.

A lubrication system ensures the smooth operation of rotating parts, while guide vanes optimise the flow through a diffuser, minimising energy loss. Centrifugal compressors are used in refrigeration, jet engines, and internal combustion systems because they can efficiently handle large volumes of air.

The choice of a compressor that suits specific needs depends on parameters like flow rate, pressure requirements, and the intended application.

This article covers these high-performing machines’ applications, types, benefits, and technical details so you can fully understand them.

What are Centrifugal Compressors Used For?

Oil & Natural Gas: used to compress gases for transmission in pipelines, hydrocarbon processing, and other refinery processes.
Automotive: pneumatic systems in assembly lines.
Food and Beverage: oil-free air for refrigeration systems, packaging, and processing.
Chemical and Petrochemical: volatile gases at high pressure.
Power Generation: compressed air for gas turbine operations.
Textile Manufacturing: consistent air pressure for spinning and weaving machines.
Wastewater Treatment: aeration in water purification process.
HVAC: a key component in large-scale air conditioning systems

Centrifugal compressors also handle different pressure ratios and flow rates, making them a solution for various industrial requirements.

Types of Centrifugal Compressors

Different types of air compressors are available based on pressure requirements and applications:

Pressure Range

Blowers (up to 1.5 bar): used in wastewater treatment and low-pressure applications.
Medium-Pressure Compressors (up to 13 bar): for sensitive industries like food and beverage.
High-Pressure Compressors (up to 205 bar): for demanding applications like gas processing and LNG.

Design

Single-Stage Compressors: for lower pressure applications with high flow rates.
Multi-Stage Compressors: for higher pressure through multiple impellers.
Inline vs Overhung Models: inline compressors support multiple stages. Overhung models are compact and easy to maintain.

Benefits of Centrifugal Compressors

The biggest advantage of centrifugal compressors is their ability to generate a high-pressure ratio and process high volumes of air/gas. Other benefits include:

Oil-Free Operation: for product purity in sensitive applications.
Low Maintenance: fewer moving parts reduce wear and tear.
Energy Efficiency: optimised design minimises energy loss.
Durability: robust impellers and bearings extend life.
Scalability: can be adapted to changing industrial requirements.

What is the Difference Between a Centrifugal and Reciprocating Compressor?

How does a centrifugal air compressor shape up compared to other types?

Feature	Centrifugal	Axial	Reciprocating	Screw
Flow Rate	High	Very high	Low to medium	Medium to high
Pressure Capability	Medium to high	Medium	High	Low to medium
Maintenance	Low	Moderate	High	Moderate
Applications	High-flow, high-pressure	Power generation	Precision applications	Continuous operations
Energy Efficiency	High	High	Moderate	Moderate to high

Centrifugal compressors are high-flow, high-pressure machines with low maintenance due to fewer moving parts – perfect for the energy, petrochemical, and manufacturing industries.

Compared to axial compressors, they have lower flow rates – they cannot generate the same axial thrust – but are less sensitive to load changes and, therefore, more stable.

The main difference between centrifugal and reciprocating compressors is that centrifugal models require less maintenance and downtime, which is critical for continuous operations.

Screw compressors are good for low to medium pressure. Reliable centrifugal compressors generally provide a more efficient and scalable supply of compressed air for demanding applications, which makes them a cost-effective long-term industrial solution in many sectors.

Find the Compressor that Suits Your Needs

Choosing the right centrifugal compressor is critical to efficiency, cost savings, and long-term reliability. Here are why these considerations matter, how to get it right, and what happens if you get it wrong.

Technical Considerations

Pressure and Flow

Every application has specific pressure and flow rate requirements. A mismatch will result in energy waste, underperformance, or equipment failure.

Analyse your system requirements and peak and average demand, and talk to Control Gear to ensure the compressor is sized to your needs.

A unit with too little capacity will create bottlenecks and process disruptions. A unit that is too big will consume more energy converting kinetic energy into potential energy (pressure) and be less efficient overall.

Material Compatibility

Compressors handling corrosive or reactive gases must use materials that are safe and resistant to chemical wear.

Identify the gases in your process and choose materials like stainless steel, aluminium or specialised alloys based on their compatibility.

Incompatible materials will result in corrosion, contamination of the compressed gas, safety hazards, and premature equipment failure.

Energy Efficiency

Energy is an operational cost. Compressors designed for energy efficiency save you money and the environment.

Look for features like magnetic bearings, advanced impeller design, and permanent magnet electric motors. Check the manufacturer’s energy consumption data, lifecycle costs, and efficiency ratings.

A less efficient compressor will cost you more in utility bills, create a bigger carbon footprint, and potentially prevent compliance with energy regulations.

Control Systems

Advanced control systems improve compressor performance by providing real-time monitoring, energy optimisation, and predictive maintenance.

Choose compressors with integrated controllers, such as the Elektronikon by Atlas Copco system. Ensure compatibility with your facility’s automation systems for easy integration.

Operators will struggle to monitor performance without proper controls, resulting in inefficiencies, unplanned downtime, and higher maintenance costs.

Installation Space

Your facility layout will dictate the type and size of compressors you can fit.

Measure the space and consider modular or compact designs, such as overhung models, for tight spaces. Inline configurations may be better for facilities with more room.

A unit that does not fit the space will require redesigns, cause operational delays, or compromise maintenance access.

Getting the right centrifugal compressor means knowing your requirements, talking to experts, and considering the choices. If you get it wrong, you will have inefficiencies, higher costs, and safety risks. If you get it right, you will have performance, cost savings, and a smooth operation for years to come.

Maintenance and Troubleshooting

Proper maintenance is essential for air compressors designed for industries that require reliable, high-performance air supply. While single and multi-stage centrifugal compressors offer durability, neglecting maintenance can lead to airflow inefficiencies, overheating, and pressure loss.

Key Maintenance Practices

Impeller and Diffuser Cleaning – the impeller is connected to a high-speed drive shaft, and the eye of the impeller disk must remain free of debris to maintain efficiency.
Bearing Lubrication – essential for low-pressure air and high-speed applications, reducing wear and overheating risks.
Seal and Leak Checks – ensures the compressor outlet maintains pressure without loss.
Airflow and Temperature Monitoring – the intake air and air temperature should be regulated to prevent performance issues.
Control Systems & Predictive Maintenance – advanced systems, such as those used in Atlas Copco UAE models, improve efficiency and fault detection.

Common Troubleshooting Issues

Reduced Pressure or Airflow – check for blockages in inlet guide vanes and clean the impeller disk and diffuser vanes.
Vibrations or Noise – inspect bearings and ensure the disk is a diffuser vane and is properly aligned.
Overheating – monitor airflow, ventilation, and lubrication levels.
Unexpected Shutdowns – verify control settings and power supply stability.

A proactive maintenance schedule ensures centrifugal and axial compressors operate at peak efficiency, reducing downtime and ensuring cost-effective performance in the power generation industry and other critical applications.

Get the Most From Your Centrifugal Compressor

Centrifugal compressors are used in industries that require high-pressure, high-flow air or gas. Oil-free air, low maintenance, and high efficiency make them valuable assets in many industrial applications. Know the types, applications, and benefits to choose the right compressor for your operating requirements.

Get the most from centrifugal compressors by consulting a Control Gear specialist to determine the best configuration for your needs.

FAQ

How does a centrifugal compressor work compared to other types?

Centrifugal compressors operate on the principle of centrifugal force. Air is drawn into the impeller and accelerated before passing through a diffuser to convert kinetic energy into pressure. Unlike positive displacement compressors, which trap and compress air in a fixed volume, centrifugal models rely on continuous airflow and dynamic compression. This makes them ideal for industries and applications requiring high volumes of compressed air with minimal maintenance.

What are the main types of compressors, and where do centrifugal models fit?

Compressors range from positive displacement types, such as reciprocating and screw compressors, to dynamic compressors, including centrifugal and turbo compressors. Centrifugal compressors are key in many high-demand industries due to their ability to handle large airflow efficiently, making them suitable for power generation, HVAC, and process gas compression.

Why is the impeller and diffuser design important in centrifugal compressors?

The impeller disk is a diffuser that plays a crucial role in pressure generation. As air enters the impeller, it gains kinetic energy, which is converted into pressure energy in the diffuser stage. This design ensures efficient compression, making centrifugal compressors highly effective for continuous operation in applications requiring a steady, oil-free air supply.