ZERUST RECAST-RE CAST ROOF TANK PROTECTION

Tank Roof Protection

The Zerust inhibitor forms a protective layer that prevents corrosion in a highly aggressive environment (H2S, SO2, etc.).

Product Applications

• All metallic surfaces contacting vapor space within the tank roof can be protected.
• Sidewall sections of the tank above the level of the stored product and support structures.
• Both new and old tanks. Even if the corrosion has started, the solution, once deployed, inhibits further corrosion.
• In operational tanks. The inhibitor does not contaminate the stored crude oil products.

Problem

Certain grades of oil that contain sulphur emit corrosive vapors that destroy the internal surfaces of storage tank roofs and their support structures above the product layer. Aggressive pitting and crevice corrosion create holes in the tank tops that cause unsafe operating conditions and environmental problems. Internal tank coatings decrease surface corrosion but have proven to be ineffective in preventing dangerous pitting and crevice corrosion especially in the interstitial spaces between the roof and support structures.

Solution

NTIC has developed the Zerust® ReCAST-R solution to protect the interior surface of AST roofs, consisting of dispensers that deliver the proprietary inhibitor formulations into the vapor space between the surface of the product and tank roof. The Zerust inhibitor forms a protective layer that prevents corrosion in the highly-aggressive environment (H2S, SO2, etc). Zerust ReCAST-R solution can be implemented to extend the service life of a single tank roof to 25 years and beyond. Each system is tailored to the client’s requirements, depending on specific environmental conditions, product stored, tank diameter, and can be applied on both new and existing roofs.

ZERUST FLOATING ROOF LEG

Problem

Between inspection intervals, it is common to move the roof legs on floating roofs, up into the “low legs” position. This is to reduce the possibility of landing the legs on the floor while drawing down on the tank contents. As this cycle is often 10 years or more, it is also common for corrosion to build up between the roof leg and the sleeve attached to the roof deck. The corrosion buildup can cause the leg to seize in the sleeve and require considerable effort/cost to move the legs to the “high leg” position prior to tank turnaround.

Solution

Zerust® has developed Zerust® Axanol Z-Maxx a proprietary heavy grease product with Zerust corrosion inhibitors. This treatment method cost-effectively reduces corrosion rates in this area using existing and proven corrosion inhibitor products. Trials of the Roof Leg Saver system have provided excellent results. An example of these tests is shown using 50 roof legs, below. A “Control” and 3 protective options were installed. In each of the 4 configurations, coupons were inserted between the roof leg and the sleeve. The “Control” and “Z-Maxx” options were exposed to the atmosphere and the others were enclosed in a Zerust VCI treated polyethylene “Sock”. Additional VCI chemistry was added to the 4th test option, but it was determined that it did not provide any additional protection to the Z-Maxx + Sock configuration.

Product Applications

• These installation instructions must be followed.
• Do not install or open pails with Z-Maxx in wet condition.
• Remove build-up corrosion from the leg surface.

Before beginning installation:

• Identify all parts of the Installation kit shown to the right.
• Gather all materials and tools.