During loading or unloading of oil tanks, the release of air and oil vapors causes three major damages, which are: the possibility of fire, environmental damage due to the release of hydrocarbon vapors, and the loss of valuable vapors. For this reason, the collection of these vapors is considered, and the purpose of the VRU package is to separate hydrocarbon vapors from the air, convert the vapors to liquid, and return them to the tank.

There are two main methods for the vapor recovery process, which are:

The first method: surface absorption technology on activated carbon (Carbon Absorption) and then vapor absorption (Absorption) in the absorption tower

The second method: Refrigeration method which is efficient for large volumes, and in this method, hydrocarbon vapors are compressed in one (or more) stages and cooled using the fluid itself or a refrigerant fluid, and after liquefaction, they are transferred to the primary tank.

Both of the above technologies are provided by HEDCO.