A vapor recovery unit compressor boosts recovered hydrocarbon vapor to a pressure where it can be condensed or absorbed into liquid product. Compressor selection is a critical part of VRU design, matched to vapor flow, composition and discharge pressure. PollutionCtrl VRU compressor packages use Bitzer piston compressors or Copeland screw compressors, depending on the duty.
How a VRU compressor works
- Suction – Hydrocarbon vapor is drawn from tanks or loading operations into the compressor.
- Compression – A piston (Bitzer) or screw (Copeland) compressor raises the vapor pressure.
- Recovery – The compressed vapor is condensed or absorbed into liquid product for reuse.
- Return – Uncondensed gas returns to the vapor recovery loop, and recovered liquid is stored or returned to process.
Piston vs screw compressors for vapor recovery
| Type | Best suited for |
|---|---|
| Piston compressor (e.g., Bitzer) | Lower to medium vapor flow, high discharge pressure, flexible turndown |
| Screw compressor (e.g., Copeland) | Higher vapor flow, continuous duty, smooth operation |
Typical technical considerations
- Vapor flow and composition – determines compressor size and materials;
- Suction and discharge pressure – set by tank conditions and recovery pressure;
- Temperature control – interstage cooling for high-ratio compression;
- Safety – gas detection, pressure protection and explosion-proof design;
- Driver – electric motor with VFD for load variation.
Frequently asked questions
What is a vapor recovery unit compressor?
A VRU compressor boosts recovered hydrocarbon vapor pressure so it can be condensed or absorbed into liquid product, improving recovery efficiency.
What type of compressor is used in a VRU?
Piston compressors (such as Bitzer) suit lower to medium flow and high pressure; screw compressors (such as Copeland) suit higher flow and continuous duty. Selection depends on the vapor duty.
Why does a VRU need a compressor?
Most vapor recovery processes require the vapor pressure to be raised before condensation or absorption is practical; the compressor provides that pressure boost.
What is a Bitzer compressor used for?
Bitzer piston compressors are used in vapor recovery and refrigeration applications where medium flow, high pressure and flexible turndown are required.
What is a Copeland screw compressor used for?
Copeland screw compressors are used in higher-flow vapor recovery duty, providing smooth continuous compression with good efficiency.
How do I size a VRU compressor?
Sizing is based on vapor flow, composition, suction and discharge pressure, and operating schedule; the compressor package is engineered with the rest of the VRU.
How much does a vapor recovery compressor cost?
Cost depends on compressor type, vapor flow, discharge pressure and package scope. Send your vapor parameters for a preliminary budget estimate.
Do you supply VRU compressor packages?
Yes. PollutionCtrl supplies VRU compressor packages using Bitzer piston or Copeland screw compressors, integrated with the vapor recovery system and controls.
Request a project evaluation
Send your vapor flow, composition, tank pressure and recovery target for a VRU compressor recommendation.