Positive displacement air compressors dominate the market due to their broad applicability and low operating costs. These compressors can be categorized into reciprocating compressors and rotary compressors, with the latter further divided into screw compressors, liquid ring compressors, etc. Rotary compressors are widely adopted in industrial fields owing to their simple structure, stable operation, easy maintenance, and low noise.

Dynamic compressors (turbine compressors) are often used in downstream of the oil and gas industry to maintain or increase gas flow into pipeline systems. As reservoir pressure declines over time, compressed gas is reinjected into oil fields for enhanced oil recovery (EOR) to mitigate natural production decline.

Upstream oil and gas exploration and drilling

In gas lift operations during upstream oil and gas activities, low-pressure gas (3–7 bar) is compressed to higher pressure by air compressors and circulated through the casing-tubing annulus. The gas enters the tubing via gas lift valves at predetermined rates to reduce the hydrostatic pressure of the fluid column.

Air drilling technology:

(Onshore oil and gas drilling platform)

Onshore oil and gas drilling platforms utilize diesel portable air compressors to supply high-pressure air (>20 bar) for driving drilling mud circulation. The portable air compressor provides power for gas injection and drainage during oil extraction, reduces formation damage, and enhances drilling speed.

Diesel portable air compressors are ideal for remote off-grid environments and can serve as emergency generators. Typical parameters for diesel portable air compressors include:

Discharge pressure: 20–35 bar

Flow range: 30–80 m³/min

Explosion-proof certification: ATEX Zone 2 certification is mandatory for safe exploration and drilling operations.

Instrument air systems:

Oil and gas drilling platforms require oil-free screw air compressors (e.g., Kotech KWI water-lubricated air compressor series) to drive blowout preventers (BOPs) and pneumatic valves, avoiding oil contamination. Key requirements of these oil free air compressors include:

Pressure: 7–10 bar

Air quality: ISO 8573-1 Class 0 (oil content ≤0.01 mg/m³).

Pipeline transportation and maintenance:

Compressed air is used for purging compressed natural gas pipeline control systems to ensure safety. Even trace oil residues can create flammable environments, necessitating strict oil-free air standards. Oil free dry air compressors are commonly used for purging and pressure testing:

Pressure requirements: 8–12 bar (purging), 20–30 bar (pressure testing)

Flow adaptation: Adjusted based on pipeline diameter (e.g., ≥60 m³/min for DN500 pipelines).

FPSO marine systems: Offshore oil&gas platforms require low-power oil-free air compressors (e.g., KUW scroll compressor series) for instrument air, which must resist salt spray corrosion. Typical configurations include:

Pressure: 6–8 bar

Post-treatment: Dual-compressor systems + air dryers (dew point ≤-40°C).

Downstream oil & gas refining and LNG

Catalytic cracking units: Processes such as desulfurization, catalyst regeneration, and acid gas oxidation demand large volumes of compressed air. Centrifugal compressors are preferred for their high capacity, continuous operation, and oil-free output. Typical parameters of centrifugal compressors for this link include:

Air handling capacity: 200–1000 m³/min

Temperature resistance: Outlet gas temperature ≤200°C.

Booster combustion and gasification: High-flow booster air compressors or centrifugal compressors supply combustion air to refinery boilers. Common parameters:

Pressure: 10–15 bar

Discharge capacity: 50–300 m³/min.

LNG liquefaction and storage: Multi-stage high-pressure centrifugal compressors are used in nitrogen separation systems. Compressed air is processed via membrane separation to produce nitrogen (≥99.999% purity) for LNG storage and catalyst transport. Typical parameters:

Air pressure: 30–40 bar.