What is a Gas Storage Tank? Your Complete Guide
You can find large fuel tanks all over the oil and gas industry. They help store liquids (gasoline or diesel) and gases for a short period of time at extraction sites. Fuel tanks can be used for even longer durations at refineries or tank farms. The vast majority of commercial establishments and industries that use fuels in their operations also use large liquid or gas storage tanks.
The American Petroleum Institute (API 650 standard) regulates the design, fabrication, installation, and inspection of all the welded storage tanks in the oil and gas industry. Since petroleum products are flammable, all oil and gas extraction sites house associated risks. Fuel tanks with double walls provide added safety to the site and for workers.
This article will discuss the types of tanks needed to store industrial gases. We’ll also explore with aboveground and underground tank options.
Where is Gas Stored?
Both natural and industrial gases can be stored either underground and aboveground. Each option comes with its own set of specifications and benefits. The choice depends on how you intend to use the tank now and in the future.
Aboveground Gas Storage
Just as the name suggests, these storage tanks are situated aboveground. They house gases in both liquid or gaseous forms. They remain an excellent option for when dealing with a low construction budget. These will cut out costs associated with deep excavation, backfilling, and pavement construction for the pipelines.
Aboveground fuel tanks are also useful when you want to store gas temporarily and before transport.
Underground Gas Storage
Storing gases underground is not uncommon, either. The move helps ensure safety and maximizes space on site. It also allows you to store fuel tanks at high pressure since the weight of the soil provides the structure with the required stability.
Because they remain protected from environmental factors, products and materials experience a longer shelf life when stored in an underground tank. You can see them scattered across man-made tank farms, offering backup when supply runs low.
Underground tanks often store hazardous liquids and gases, which is why they must meet all requirements specified by the Environmental Protection Agency (EPA). Inspections don’t take place frequently, which increases the possibility of leaks and faults going unnoticed. Fortunately, chances of an explosion remain minimal.
Other popular ways to store natural gas underground are:
- Salt formations or caverns - You can inject natural gas into underground salt formations and withdraw it when needed. Salt formations account for approximately 10% of all the natural gas reservoirs in the US. These storage formations are primarily located in the gulf coast states. Salt formations feature very high injection and withdrawal rates.
- Hard rock caverns - Inject the gas into natural hard rock formations and recover when needed. This works on the same principle as salt formations.
- Depleted aquifers - With an impermeable cap, depleted aquifers are ideal for storing gas underground. 10% of reservoirs for natural gas in the US are depleted aquifers. These aquifers are not a part of those that supply drinking water.
- Depleted oil wells or reservoirs - Depleted wells have an existing piping system that you can reuse for pumping gas in or out. Approximately 80% of the reservoirs for natural gas in the US are depleted oil wells. This comprises about 400 active underground oil wells.
- Mines - Spent mines are great for safely storing gases underground.
Each method listed above traps the gas inside non-porous rocks. The gas will share the space with salt and water, especially when stored in aquifers.
The existing network of pipelines, valves, and sealing systems provide an easy way to fill gas and extract it for transportation whenever required.
These methods gained popularity after World War II when the pipeline supply fell short of demand. Each underground facility undergoes reconditioning before injection, which is why some consider them natural and pressurized underground storage tanks.
Types of Industrial Gas/Liquid Fuel Tanks
Industrial and natural gas tanks come in different shapes and sizes. They range from small 25-gallon tanks to large underground units that hold millions of gallons of gas and fuel. Before you begin searching for equipment, consider the following factors:
- Application of the tank
- The capacity of the tank
- Your budget vs. the price of the tank
Once you locate the answers, consider the following tank options:
Fixed Roof Tanks
Fixed roof tanks are normally cylindrical, with a fixed roof attached to the shell. These tanks feature pressure-vacuum valves and vents to maintain the ambient pressure (0.5 PSI).
These storage tanks can hold any liquid, be it gasoline, diesel, or chemicals. Local municipal authorities like a fire department will use these tanks to store large quantities of water. This type of tank conforms to the API 650/ 620 or American Water Works Association (AWWA) D100 standards.
Floating Roof Tanks
This tank has a roof that floats directly over its contents. While a floating roof tank stores most liquids, it is used extensively across the petroleum products industry.
The biggest advantage of a floating roof tank is the vapor management of volatile compounds (VOCs) and other air pollutants. Floating roof tanks improve overall safety and reduce the risk of product loss.
The two types of floating roof tanks are:
- External floating roof tanks (EFR) - These tanks expose contents to the atmosphere at the rim, or the area between the tank's shell and the floating roof.
- Internal floating roof tanks (IFR) - Internal floating roof tanks allow you to store liquids with low melting points such as gasoline or ethanol and even gases. The floating roof is inside an external fixed (often conical) roof.
The floating roof moves up or down depending on the level of the tank's contents. When the level is low, the roof settles on the legs inside the tank.
Pressure Tanks (High-Pressure Vessels)
Pressure tanks and pressure vessels are often used interchangeably. However, there is a big difference between the two. While pressure tanks have a maximum allowable operating pressure (MAOP) of 15 PSI, pressure vessels can handle up to 3000 PSI (and more in special provisions).
Used in a wide range of industries, pressure vessels can store petroleum products, liquefied gases, and water. All high-pressure vessels fall under the ASME boiler and pressure vessel code. This code regulates the design, fabrication, material, testing, and quality certification of pressure vessels.
Bullet tanks are either in the shape of a sphere or a horizontal cylinder with rounded ends (such as a bullet). These over-the-ground tanks are ideal for storing liquefied gases such as butane and ammonia that have a very low melting point.
The tank stores gases and liquids below -148 degrees Fahrenheit, ranging from 5,000 to 30,000 gallons. Bullet tanks can hold fuel with other additives that may be necessary to run an industrial plant.
LNG Storage Tanks
LNG tanks store liquefied natural gas at extremely low temperatures (-162 degrees Celsius). These storage tanks have an inner shell that holds the gas and an outer shell that holds the insulation. LNG storage tanks release the vapors periodically to prevent the temperature and pressure from rising and causing blowouts.
Difference Between CNG and LNG
While compressed natural gas (CNG) is often confused with liquefied natural gas (LNG), it is important to note the difference.
- Compressed natural gas is stored at ambient temperature and high pressure.
- Liquefied natural gas is stored at low temperature and ambient pressure.
It is cheaper to store CNG because it does not require temperature control and tanks with double walls. Trains, ships, and pipelines carry natural gas over long distances in the form of LNG and convert it to CNG before distributing it to the customer.
21K Closed-Top Frac Tanks: An Industrial Storage Solution From Adler Tank Rentals
A 21,000 Gallon (500 BBL) Closed-Top Frac Tank can be used for large-scale storage of hazardous and non-hazardous fluids, such as transformer oil and fuel.
- Non-slip step materials on stairs and catwalks
- “Safety yellow” rails and catwalks for high visibility
- Safe operation reminder decals
- Safety side stairway—no mechanical guard rails to set up
- Strapping charts
Fuel Tank Maintenance and Inspection
- All fuel storage tanks, if not inspected regularly, can contribute to fatalities. Below are a few risks to watch out for:
- Flammable hydrocarbon build-up inside empty gasoline or diesel tanks could ignite from welding sparks.
- Sub-standard steel, riveting, and welding jobs could become weak with corrosion and give up under pressure.
- Poor construction and design.
- Insufficient testing before industrial usage could result in tank failure or reduce the shelf life of the contents due to condensation.
It is important to choose a fuel storage tank that already adheres to the design, fabrication, and safety standards. You should also perform regular fuel tank inspections in consultation with the rental company.
Rent gas buster tanks from Adler Tank Rentals for your oil and gas drilling site. Call us at 800.279.6310 with your exact requirements, or message us for a free quote.
We will quickly deliver the tank to your location. Every second wasted results in extra money spent. That is why our container stock is available 24/7/365 to serve your last-minute rental needs.
When you are dealing with large quantities of fuel in the form of liquid or gas, it is important to select a tank with the right size and material and in your budget. Because it is such a big investment, you should begin by consulting the service provider about the appropriate solution for your needs.
Whether you store liquid fuels, natural gas, or industrial gas, it is imperative to ensure that the tank has passed the minimum safety criteria.
Is Natural Gas Stored Under Pressure?
Natural gas is mainly stored and transported in two forms: CNG and LNG. Compressed natural gas is stored at ambient temperature and high pressure. In contrast, liquefied natural gas is stored at low temperature and ambient pressure.
Where Do You Place Fuel Tanks?
Fuel tanks cannot be located in areas prone to flooding, wells, boreholes, or springs. Uncontained spills can also pollute surface water, impact drinking water supplies and harm wildlife.
- Up to 3,500 liters of fuel in a diesel storage tank should place it at least 2 meters away from any building.
- Volumes more than 3,500 liters should be placed at least 6 meters away from any building.
- It must always be away from ignition sources like welding and cutting torches.
- The location should be easily reachable for routine maintenance.
- The tank should be placed on flat ground so that spills and leaks do not run downhill towards creeks, ditches, tiles, or drains.
How Do You Store Gas Long-term?
Usually, liquids (gasoline or diesel) and gases (chemicals, CNG, etc.) are stored at the extraction site for a short period of time. They can be used for even longer durations at refineries or tank farms.
The vast majority of commercial establishments and industries that use fuels in their operations use various types of gas storage tanks, including underground and aboveground tanks, floating top, gas buster, fixed top, or bullet tanks.