Class 0 Compressed Air: Why the Cement Industry Cannot Operate Without It

In a cement plant, compressed air is not a secondary utility. It is an integral part of the production process from the first stage to the last. It is used to convey pulverized materials, actuate rotary valves, operate baghouse filters, control automation systems, and move finished cement toward loading silos.

At every stage of this process, there is one requirement that allows no exceptions: the air must be completely free of oil and moisture.

The Silent Enemy: Compressed Air Contamination

Cement is a highly hygroscopic material, meaning it reacts immediately to the presence of moisture or oil vapors in the air. When this occurs, cement dust or clinker can harden and agglomerate, clogging pipelines, filters, and conveying systems—rendering the product unusable and halting plant operations.

The practical consequences of contaminated compressed air in a cement plant include:

• Control valve failures caused by oil residues in pneumatic actuators
• Blockages in conveying lines due to material agglomeration
• Degradation of baghouse filters, which are critical and costly components
• Unplanned shutdowns, which in continuous operations can represent multimillion-dollar losses

For this reason, all process stages downstream of the rotary kiln must rely on extremely dry, completely oil-free compressed air.

What an Oil-Free Scroll Compressor Is — and Why It Matters

A scroll compressor operates using two interleaving spiral elements: one fixed and one orbiting in a circular path without rotating. This motion traps air in compression chambers that progressively decrease in volume, compressing the air until the required working pressure is reached.

The key aspect of this design is that the two scroll elements never come into contact, completely eliminating the need for oil lubrication.

This is more than just a technical advantage. It is precisely why scroll compressors can be certified under ISO 8573-1 Class 0, the most stringent compressed air purity standard, which guarantees zero risk of oil contamination in the air supply.

1. Protection of Instrumentation and Control Systems

Automation systems in a cement plant rely on instrument air to operate actuators, control valves, and pneumatic cylinders.

Even trace amounts of oil in this circuit can cause instrument malfunction, inaccurate readings, and loss of process control. A Class 0 scroll compressor eliminates this risk at the source.

2. Reduced Maintenance Across the Pneumatic Network

Because no oil is introduced into the system, costs associated with frequent replacement of coalescing filters, contaminated condensate treatment, and repair of degraded valves are significantly reduced.

In practice, the only routine maintenance required for a scroll compressor is the periodic replacement of inlet filters.

3. Quiet and Continuous Operation

The spiral compression geometry of scroll compressors eliminates the impacts and pulsations typical of piston compressors, resulting in significantly quieter operation and lower vibration levels.

In plants where multiple systems operate simultaneously, this helps reduce cumulative wear on piping, fittings, and support structures.

A Decision That Impacts the Entire Lifecycle of the System

Choosing an oil-free scroll compressor is not merely a technical decision for the instrumentation department. It is a strategic investment that protects product quality, reduces corrective maintenance, and extends the service life of the plant’s entire pneumatic network.

In an industry where a single unplanned shutdown can cost more than several years of preventive maintenance, Class 0 compressed air stops being a luxury and becomes the minimum acceptable standard.

Is your cement plant already operating with Class 0 compressed air?

Every facility has its own flow, pressure, and distribution requirements. Our specialists can help you identify the right solution for your operation:
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Frequently Asked Questions

Why must compressed air in a cement plant be free of oil and moisture?

Because cement is a highly hygroscopic material that reacts immediately to moisture or oil vapors in the air. When that happens, cement dust or clinker hardens and agglomerates, clogging pipelines, filters and conveying systems.

What problems does contaminated compressed air cause in a cement plant?

Control valve failures caused by oil residues in pneumatic actuators, blockages in conveying lines from material agglomeration, degradation of baghouse filters — critical and costly components — and unplanned shutdowns.

What is an oil-free scroll compressor?

It is a compressor that operates using two interleaving spiral elements, one fixed and one orbiting without rotating. The two scroll elements never come into contact, which completely eliminates the need for oil lubrication.

What does Class 0 compressed air mean?

It is the most stringent purity level in the ISO 8573-1 standard, guaranteeing zero risk of oil contamination in the air supply. Scroll compressors can be certified under it precisely because they require no lubrication.

What does a cement plant gain from Class 0 air?

It protects instrumentation and control systems, reduces maintenance across the pneumatic network — fewer coalescing filter changes, less contaminated condensate, fewer degraded valves — and runs with lower noise and vibration than a reciprocating unit.