Vapor Corrosion Inhibitors (VCI)
Tanks, Casings, Pipelines & Plant Piping

If you are building a new pipeline, as a section is completed, it is typically hydrotested using water from local nearby sources. After hydrotest, many owners will dry the section and purge the atmosphere with Nitrogen. Often, these lines are not completely dry and the combination of water, oxygen and bacteria, can have a negative corrosion effect on this new steel, even if the line has a Nitrogen blanket. Maintaining the Nitrogen can take time and be expensive, especially if the line will not be commissioned for a period of time.

The VCI preservation solution can be introduced into piggable and non-piggable pipeline or station pipe segments for many years. When it is time to put the line into service, there are options for removing the small amounts of VCl slurry, or in some cases, simply start pumping the product. Similarly, existing lines can be preserved by VCI after cleaning.

Using VCI to protect pipe casings is a cost-effective option to extending the life of these important assets. Corrosion rate monitoring can be provided using ER probes or coupons. Installation of the VCI and monitoring equipment, in most cases, can be accomplished through the vent pipes without excavation.

High Viscosity Gel Application – For pipelines with a metallic short (i.e. casing in contact with the carrier pipe) or pipelines where a static fill anti-corrosion solution is needed.

Powder Application – For pipelines without a metallic short, but for which providing internal corrosion protection is a good operating procedure, Zerust recommends the use of its dry powder inhibitor. As long as there is minimal water ingress (i.e. end seal integrity is maintained) the system will protect the carrier pipe from corrosion.

Slurry Application – For long lengths of pipe with varying elevations, bends and other geometric/dimensional parameters where a powder or gel is not feasible. Zerion FVS is first mixed with water. Gravity or a low-pressure pump is then used to inject the inhibitor slurry through the casing vent pipe into the annular space. The SCI in the product neutralizes contaminants on contact.

Below are methods of introducing a VCI to the tank bottom environment, based on the design of the foundation and whether the tank is in service or out of service. Each can be used with cathodic protection systems and can be provided with monitoring provision.

Chime Ring Dry – This system is recommended for storage tanks with concrete or bitumen foundations. Perforated PVC pipe is installed around the entire annular chime area. The VCI dry sleeves are installed into the PVC pipe and the system is sealed to create an enclosure to maintain the VCls. The VCls migrate and absorb onto the metal surface.

Chime Ring Flood -Is suitable for storage tanks with concrete, bitumen, or sand with liner foundations. The inhibitor slurry is pumped into the perforated PVC chime ring system, the VCls migrate and absorb onto the metal surface.

Underside Injection – Is designed for tanks with compacted sand fill and Release Prevention Barriers (RPBs), Double Bottom with sand between the old and new floors, or tanks sitting on a hard pa such as concrete or asphalt.

Internal Flood – The Internal Flood IDS solution is suitable for tank foundations of concrete, bitumen, or compacted sand with liners.

Dry Tube – This system is designed to protect tank bottom plates during construction or new floor installation. This solution benefits tanks with concrete, bitumen, and compacted sand foundations with or without liners. Shallow trenches are cut into the foundation.

Drip Tube – Is an innovative solution that protects tank bottom plates of single or double bottom tanks during construction or new floor installation. A network of perforated PVC pipes with mesh sleeves are installed in rings on top of the tank liner in the sand foundation.