What is a Vapour Recovery Unit?

VRUs address ongoing issues with tank vapours in industrial systems. Tank vapours are volatile organic compounds (VOCs) released from liquids stored in tanks, such as fuel or oil. They are a product loss, an emissions risk, and, in many cases, a compliance issue.

A vapour recovery unit, often shortened to VRU, is designed to capture harmful vapours that would otherwise vent to the atmosphere and compress them for reuse. The U.S. EPA describes VRU operation as "pulling hydrocarbon vapours from tanks under low pressure and routing them through a suction scrubber to remove condensed liquids before compression."

At Eagle Pump & Compressor, we build vapour recovery solutions that precisely match the needs of each field's specific realities. We know how important it is to conduct a full inspection and system audit before creating a VRU plan and installation. Vapour composition changes, liquids show up when you do not want them, and inlet conditions can be finicky.

A VRU that is properly sized, controlled and protected is the difference between steady recovery and a package that trips out every time the weather changes. 

What is a VRU in the Oil & Gas Industry? 

A VRU in the oil & gas industry is typically installed on storage tank batteries, separators, heater treaters or other sources of flash gas and working vapours. The intent is to pull vapours off the tanks at low pressure, separate any liquids, and compress the vapour stream to a pressure at which it can be routed to a productive destination.

That detail matters because many field problems start at the inlet. If liquids are not handled properly, the compressor won't function efficiently. In heavy oil applications, the control strategy and inlet restrictions can be even more important because vapours can be difficult to handle, and carryover risk increases.

Our vapour recovery page outlines how we design packages for these kinds of operating conditions, including heavy oil tank vapour recovery and low-pressure inlet control.  

How Does a Vapour Recovery Unit Work? 

First, vapours are pulled from a tank or vapour header at low pressure. Second, the stream enters a suction scrubber or separator, where the condensate is removed and typically returned to the tank system.

Third, the compressor raises the vapour pressure to meet a destination requirement. Lastly, a control system keeps the package stable, ensuring the tanks remain protected and recovery remains consistent. 

In practice, control and protection are the most important factors. Stable inlet pressure control, reduced inlet restriction, proper liquid management, and proper shutdown logic prevent nuisance trips and protect your equipment. Eagle’s vapour recovery systems are designed around those operational realities, not just theoretical flows. 

What Equipment Details Matter Most for VRU Performance? 

Tank vapours are rarely clean, steady or dry. Working vapours change with throughput and temperature, and flash vapours change with upstream pressure and fluid properties. Operating conditions influence vapour generation, which is why capture equipment is typically configured to accommodate that variability. A VRU designed for real variability will stay online consistently. 

If you are reviewing a new VRU project, we can help you match the package to your tank battery, vapour characteristics and destination requirements.  

Explore our VRU solutions on our Vapour Recovery page.