What is Stage One Vapor Recovery
What is its Purpose
In stage one vapor recovery, vapors must be collected in the cargo tank as gasoline is supplied to the underground storage tank (UST) or above ground storage tank (AST). All tanks have fittings for gasoline delivery as well as vapor recovery.
Additionally, gasoline vapor recovery is a way of stretching the usefulness of gasoline further while allowing companies more profits. They hydrocarbons in the captured gasoline vapor can be separated from the vapor, condensed, and collected for reuse.
Stage One Vapor Recovery Methods
There are two main types of stage one vapor recovery methods. These methods are dual, or two-point systems, and coaxial, or one-point systems. The dual stage gasoline vapor recovery system is the most commonly used type of stage one vapor recovery.
Dual-Point Stage One Vapor Recovery
Dual-point stage one vapor recovery systems have separate points for gas delivery and the recovery of vapors. A delivery elbow and recovery elbow are fixed to each point during fuel delivery. Standard industry practice requires the vapor lid to be painted orange, allowing for easy identification.
Utilizing the dual-point stage one vapor recovery system, displaced gas vapor is recovered through two riser pipes while gas is being pumped into the storage tank. The gas is supplied via a drop tube, while vapors are forced up the riser pipes fro the ullage. Each riser pipe is equipped with a spill bucket and fitted with an adaptor and dust cap. Most spill buckets have a valve for draining accumulated gas back into the storage tank.
Coaxial Stage One Vapor Recovery
Coaxial stage one vapor recovery utilizes one pipe and elbow for both delivery of gasoline and gasoline vapor recovery. By using concentric tubing, gasoline may be pumped into the storage tank via one tube in the pipe while vapor is collected using another tube within the pipe. This limits the need for extra piping.
Coaxial stage one vapor recovery is an older form of recovery and is on the way to extinction. The use of one pipe for both delivery of gas and recovery of vapors is both outdated and inefficient. The dual recovery method allows for more efficient collection of vapors by the tanker.
We’ve already covered industrial vapor recovery and stage one vapor recovery. Next time, we’ll talk about stage two vapor recovery and how it works.