The Most Common Above Ground Oil Storage Tank Design

When it comes to above ground oil storage, the most prevalent design is the fixed roof welded steel tank. This type of tank, often seen in industrial and commercial settings, is characterized by its piping connections at the base for precipitation drainage. Ideally, such tanks are situated within a solid dike made of either earth or concrete. Concretely, the base of this dike can be lined with an asphalt or concrete ring to prevent soil erosion from rainwater runoff.

For enhanced safety and environmental considerations, these tanks should include a vacuum breaker that activates when the oil level is reduced, ensuring that pressure does not decrease to a point detrimental to the structural integrity of the tank. Additionally, a vent is provided to facilitate the flow of air when the tank is being filled. This vent often leads to an emissions control device, a critical component for meeting regulatory standards.

The filling pipe can be strategically positioned. Either directly at the base of the tank for easy access or extending from the roof to the bottom to minimize splashing and mist emissions, thereby reducing potential environmental hazards.

For tanks holding more volatile materials than diesel, such as gasoline, internal floating roofs are often employed. This design significantly reduces emissions by allowing the oil to float on the roof, reducing contact with air. Although less common, older or larger tanks might still use an external floating roof, an approach still seen in some industries.

Specialized Tank Designs for Highly Volatile Materials

When dealing with highly volatile materials such as propane, a specialized design featuring a pressurized steel sphere is more appropriate. This innovative design not only houses the material but also incorporates nitrogen padding, an added safety measure that helps maintain the safety and stability of the tank. The vent in such tanks is typically routed to a control device like a flare for effective emissions management.

Preventing Contamination and Maintenance Considerations

One key factor in maintaining the integrity of any oil storage tank is the prevention of water contamination. Over time, water can settle to the bottom of the tank, leading to corrosive conditions and complications in processing. To address this, small pipes are often installed at the bottom of the tank to facilitate the drainage of any accumulated water. This ensures that the oil remains free from contaminants that could compromise its quality and safety.

Regular maintenance and inspection are essential to uphold the performance and safety of these tanks. This includes checking for any structural damage, ensuring the functionality of all systems, and addressing any potential issues before they become major problems.

Conclusion

In the design of above ground oil storage tanks, several factors come into play, from the type of material being stored to the potential for volatility. By understanding the common and specialized designs, as well as the considerations for maintaining their integrity, facility managers can ensure reliable and safe operations in their oil storage facilities.