With the oil prices hitting subzero (-$37.63 per barrel) in the United States for the first time in history on April 20th, 2020, and the global onshore oil storage around 77% full in the same month, the oil and gas industry was compelled to look for creative alternatives to store the oil produced without having to face considerable loss.
Thanks to oil storage tanks, this requirement can be met effectively. Storage tanks are generally durable, rugged, leak-proof, weather and temperature resistant, and appropriate for both short term and long-term storage. These tanks are designed to comply with industry standards while also being high in quality to store and transport oil and other fluids with ease.
Oil Storage Tank Types and Materials of Construction
There are various kinds of oil storage tanks, each suited for different needs:
Floating Roof Tank
- As the name suggests, a floating roof tank consists of a floating roof that falls or rises as the level of oil in the tank increases or decreases.
- The floating roof helps prevent the build-up of vapor in the tank and ensures safety.
- There are two kinds of floating roof tanks: external and internal.
- External floating roof tanks have a rim seal system, which is attached to the roof perimeter and is in contact with the tank wall. This prevents evaporative losses and harmful exposure.
- Internal floating roof tanks have a permanent, fixed roof along with a floating roof inside.
Fixed Roof Tank
- Unlike a floating roof tank, a fixed roof tank has an unmovable roof. Due to its simple construction, it is the least expensive type of oil storage tank.
- This type of tank is used for holding oil products in lower volumes as compared to floating roof tanks.
- A breather valve (pressure-vacuum valve) is usually installed on many fixed roof tanks to operate them at a slight internal pressure or vacuum.
Bunded Tank
- Bunded tanks are enclosed by an additional tank or have a containment dike surrounding the tank.
- The containment dike or outer tank helps avoid leakages, oil spills, or oil contamination from reaching the surroundings.
Single Skin and Double Skin Tanks
- Single skin tanks are enclosed within a single layer, whereas double skin tanks are enclosed within two layers of plastic or steel. Double skin tanks are also known as twin-walled tanks.
Open Top Tank
- This type of industrial oil storage tank has an open roof/top and was used earlier.
- However, due to the open roof, the contents of the tank are prone to evaporation losses and are also at a high risk of catching fire. So, the use of these tanks is limited now.
- Oil storage tanks are typically made of one of three types of materials: steel, fiberglass or a combination material.
- Steel tanks are highly popular because of their cost-effectiveness. Steel can offer outstanding protection against corrosion and leakages.
- Fiberglass tanks are tough, long-lasting, and less prone to the risks of rusting, leakage, and sedimentation.
- Combination tanks are extremely tough and sturdy due to their “double wall” structure. They are made with a thick polyethylene composite inner tank and galvanized steel outer tank. This kind of construction makes them durable, safe, and reliable, but also expensive.
Why Selecting the Right Oil Storage Tank Matters
With such a wide variety of options, selecting the right oil storage tank for your operations is vital to prevent problems. Depending on the type of operation, you should select the right size to accommodate the oil. Not choosing the right size or type of oil storage frac tank may result in issues such as vapor build-up, overflow or leakages.
The right kind of storage tank should be able to strike a balance between quality, performance, and cost. It is important to assess your budget, requirements, and options and select a tank accordingly.
How to Select the Right Oil Storage Tank
While choosing an oil storage tank, keep in mind the following pointers:
1. Where is the tank to be used?
The first thing to consider is where you would like to install the storage tank. Based on the requirements, there are different types of options available, such as:
- Above-ground outdoor storage tanks
- Above-ground indoor storage tanks
- Underground storage tanks
2. How much tank storage capacity do you need?
Oil storage tanks are available in various storage capacities and range from sizes small (a few hundred liters) to large (more than 100,000 liters). If you have a flexible budget, you can consider buying a storage tank with a capacity slightly greater than your requirements, in case your operation needs to grow in the future.
3. Which material is more suitable for the construction of the tank?
Oil storage tanks can be made with steel, fiberglass, and a combination of material. Keeping in mind factors such as protection against rusting and corrosion, strength, durability, and cost, you can opt for the most suitable material.
- Steel tanks are relatively cheaper and stronger.
- Fiberglass tanks offer better protection against rusting.
- Combination tanks are the most reliable and sturdy, and highly expensive.
4. Do you need additional security features? If so, which ones?
Most oil storage tanks are fully lockable. However, if you want additional security, you can accessorize your tanks with add-ons such as locking caps, sheds, fences, closed shackle alarmed padlocks, and security lights.
5. Which regulations does the storage tank need to comply with?
Depending on the location of your job site and the operation, you are required to comply with certain manufacturing standards and safety regulations. Check whether the tanks meet these conditions.
All plastic and steel oil storage tanks should be manufactured as per OFTEC OFS T100 (plastic) and OFS T200 (steel BS 799-5) standards. The tanks also need to comply with the Control of Pollution (Oil Storage) (England) Regulations 2001 and building regulations.
Summary
There is a great variety of oil storage tanks available on the market. A lot of options can make it difficult for you to choose the right storage tanks. However, by considering parameters such as size, installation location, the material of construction, and cost, you can select the right tank for your job.