HDPE RETAIL FUEL TANKS

Retail fuel stations have been erected for many years in South Africa. It used to be infrastructure that only the oil majors owned and operated.

With oil majors, a lot of rules and regulations get written into their design manuals to specify exactly what they want and ensure a standardized design for each station.

South Africa recently changed its regulations and anybody or brand can now open a filling station in South Africa if they get the approval and license from the DOE (Department of Energy).

This has led to a number of new brands opening retail fuel stations with less stringent design codes and regulations while still following international practice and ensuring safety at all times.

The new entrants in the retail fuel market, have also started challenging certain practices that’s been done for many years in the retail fuel market. This has led to them exploring different equipment suppliers, material selections and layouts for the retail fuel stations.

Driven by innovation and commitment to the industry, a lot of effort has gone into optimizing the retail fuel station market and to provide better value to existing and new clients. One area of specific improvement is material selection for underground fuel tanks.

For many years, retail fuel tanks were single wall carbon steel tanks installed below the ground surface with no cathodic protection. Although these tanks are cheap to build and install, we find many instances where these tanks have rusted through and the fuel that was supposed to be stored in the tanks contaminated the soil around the tank.

Most of the old fuel stations in South Africa still have these tanks installed, but as stations get refurbished, the latest design tanks with a double wall get installed. These double wall tanks are a lot better than the single wall tanks, they have an inside carbon steel wall and an outside layer of GRP (glass reinforced plastic). They also measure the pressure in the cavity and can give you an indication when one of the layers starts leaking. With the outside layer of GRP, cathodic protection is not needed although it could still be installed as a backup system.

South Africa has a number of companies manufacturing these types of tanks and most of the international retail tank manufacturers can manufacture and supply these tanks. China manufactures the most of these retail fuel tanks in the world and competition from imports are very stiff.

The fact that the retail sector clients are cost sensitive combined with the cheap imports from China and the technology being mature, creates a dog eat dog market where price plays a major role in the supply of these retail fuel tanks.

This has led to the EPCM team exploring new designs and working with one of the world’s best HDPE large diameter pipe design and manufacturing companies from Germany. A new HDPE retail fuel tank was born that would change the way retail stations procure and install tanks in the future.

This fuel tank will have a capacity of 50m3 (50 000 l) and weigh only 1.4tons. This is in comparison to the 40m3 (40000l) double wall tank weighing more than 7 tons.

Installation techniques will change completely as there won’t be a need for large cranes to move the tanks into position. It will also improve the safety on the site and reduce the cost of logistics to the site.

The cost of materials will be considerably less than steel fabrication of these tanks and will have a big cost saving to the client.

Corrosion will also be something of the past as the 2-layer tank will have an HDPE outside layer and a Pipelon/PE inside layer. The outer layer will prevent any corrosion occurring on the tank and the inside layer will stop diffusion of the fuel and prevent static loading. In between the two layers, a core tube will be integrated to ensure the correct stiffness is obtained. The combined layers should be antistatic, fuel resistant and corrosion resistant.

The dome ends will be produced using the same process and having the same layers without the core tubes needed for stiffness. The dome ends will be welded to the tank shell with the electrofusion welding process.

The new retail fuel tanks have undergone 2 years of testing in Germany with the results being a big success. The tanks are now ready to enter the market and get certified in accordance with local codes and standards.

As part of the optimization process of retail fuel stations in Africa, EPCM will drive the design and supply of these tanks. The outcome of installing one of these HDPE fuel tanks at your depot would improve your capex during construction, your opex during operations and environmental challenges and potential liabilities in the future.

The design life of one of these tanks would be 100 years compared to the normal tanks that usually have to be replaced every 20 years. This will also have a big impact when retail stations change hands as the current norm is to replace tanks and pumps when stations get sold or refurbished. This means that oil companies can see their tanks as assets when selling to another company rather than an environmental liability.

The EPCM team also does a lot of large API 650 storage tanks and is currently investigating the use of HDPE in different layers to construct these tanks. This will also be a market disrupting technology as the current way of constructing API 650 storage tanks is to weld steel plates together on site. This leads to a lot of logistical problems in Africa as well as quality problems when welding the steel plates together.

By changing over to HDPE storage tanks to store fuel, most of the material and machines needed to construct these tanks could be loaded in a few containers and shipped to site. HDPE also does not have a long lead time and construction periods would be shortened considerably.

The challenge when constructing above ground storage tanks would be the selection of the material to give the tank its structural integrity. Many options exist with core tube being the most basic solution and a mesh like layer being a bit more complex. This is currently in development stages and more refinement is needed to produce a final product.

Both the extrusion and potentially 3d printing solutions are currently evaluated to determine the best available options for the HDPE fabrication on site. Site conditions will also play a big role and should be closely monitored to ensure it does not affect the quality of application. Creating a controlled environment would also work similar to a welding hut on a pipeline that controls humidity and temperature.

Although a lot of hard work still needs to be done to get these product to the market, it’s a giant leap for tank fabrication globally and in the next few years, the way we build and install tanks will completely change.