Three product properties drive the design of biofuel and ethanol terminals. Ethanol absorbs moisture from the air, and when it is blended with gasoline, excess water can make the blend separate, so the chain from storage to loading arm has to be closed and dry. Biodiesel (FAME) can start to crystallize at higher temperatures than fossil diesel and can oxidize in storage, which brings heating, insulation and limiting air contact into play. Both products are incompatible with some seals, hoses and metals. On top of that, where and how the bio-component is blended with fossil fuel sets the terminal's tank, meter and loading arm arrangement.
This page outlines the product character of terminals handling biofuels and ethanol and points to the pages on loading, metering, blending, additives and custody transfer. The general structure of fuel terminals is described on the fuel terminals page.
The product family and what matters at the terminal
Product | What matters at the terminal | Effect on design |
Denatured fuel ethanol | Absorbs water; denatured with hydrocarbons to make it unfit for drinking; tank headspace can be in the flammable range at room temperature and down to about −6 °C | Dry, closed storage, dedicated lines, hazardous area and headspace measures |
Gasoline–ethanol blends | Can dissolve a small amount of water; with more water the gasoline portion can separate from the ethanol–water mixture | Preventing water ingress, blending close to the loading point |
Biodiesel (FAME, B100) | Gel temperature varies with feedstock; can oxidize into sediment and acids; can dissolve old deposits | Heated or insulated tanks and lines, antioxidants and less air contact, filter monitoring |
Hydrotreated vegetable oil (HVO) | Hydrotreating yields compounds identical to some found in fossil diesel | Handling close to fossil diesel; product segregation and specification control still apply |
Water: the central design issue for ethanol
Ethanol is strongly hygroscopic, and handling, storage and distribution equipment should be kept as free of water as possible. Humid air entering through tank vents, connections left open and truck compartments that are not dry from the previous product are the main water sources. Key design features are drying the tank breathing path or blanketing with dry gas, a tank bottom arrangement that lets water collect and be drawn off, lines dedicated to ethanol, and blending at the moment of loading.
Cold flow and oxidation: the biodiesel side
The temperature at which B100 begins to gel depends on the feedstock; sources give roughly −3 °C to 15 °C or higher. Heated tanks and lines may therefore be needed in cold months even in moderate climates; once gelling starts, viscosity rises quickly and filters can plug. Biodiesel can oxidize during storage and handling, forming peroxides, acids and sediment. Antioxidant additives and measures that limit air contact, such as nitrogen blanketing, extend storage life.
Material compatibility
Ethanol blends can affect some metals and elastomers; at high ethanol content, zinc, brass, lead and aluminum have shown degradation, while unplated steel and stainless steel have shown acceptable resistance. With prolonged contact, B100 can also soften or permeate some hoses, seals and plastics. Both products have a cleaning effect and can mobilize deposits in tanks and lines that previously held fossil fuel, so filter plugging is expected at first start-up. Seals in pumps, meters, valves and loading arms are therefore selected against manufacturer compatibility data for the product and blend ratio.
The blending point shapes the terminal layout
The bio-component can be blended with fossil fuel in a tank, in the truck compartment during loading, or at the loading arm under meter control. Ratio (in-line) or sequential blending at the terminal rack is described as the preferred method because it ensures complete blending. For ethanol, blending close to the loading point also shortens the time a water-sensitive blend sits at the terminal. The blending method directly determines the need for a bio-component tank, separate meters, ratio control and per-component records.
Solutions for biofuel and ethanol terminals
· Ethanol truck loading systems: Keeping water out and getting material compatibility right.
· Biofuel truck loading systems: Cold flow and product segregation for biodiesel and HVO.
· Ethanol metering skids: Volume correction and meter selection for ethanol.
· Biofuel metering skids: Managing viscosity and temperature effects.
· Biofuel blending systems: Ratio and sequential blending, ratio verification.
· Additive injection for biofuel terminals: Coordinating additives with blending.
· Biofuel and ethanol custody transfer metering: Product-specific volume correction and per-component reporting.
· Fuel terminals: The fossil fuel terminals where bio-components are blended.
TLY Enerji's role
TLY Enerji provides system design, equipment supply, engineering, installation, commissioning and maintenance for fuel truck loading and unloading facilities. At biofuel and ethanol terminals, depending on project scope, these services can cover selecting meters, valves and pumps suited to the product and blend ratio, integrating blending and loading control into the PLC and SCADA architecture, and site installation and commissioning.
Frequently asked questions
Can existing gasoline tanks and lines be used for ethanol?
They can, but two issues are reviewed first. The first is material compatibility: seals, hoses and some metal parts may not suit ethanol and should be checked against manufacturer data. The second is cleanliness: ethanol dissolves old deposits and can plug filters. Cleaning the tank, checking the water draw-off arrangement and reassessing venting against moisture ingress are usually part of the conversion.
Why are biodiesel tanks heated?
Depending on feedstock, neat biodiesel can start to crystallize and gel at a higher temperature than fossil diesel. In cold weather this quickly raises viscosity, plugs filters and makes pumping difficult. The need for heating and insulation is set by the product's cloud point, the lowest site temperatures and how long the product sits before blending.
Is HVO handled the same way as biodiesel?
Not exactly. Biodiesel consists of fatty acid methyl esters made from vegetable oils or animal fats, while HVO is made by hydrotreating and consists of hydrocarbons identical to some compounds in fossil diesel. HVO handling is therefore closer to fossil diesel. The products still follow separate specifications, and keeping them from mixing is necessary for product segregation.