Bitumen is thick and tar-like in its natural state, often referenced as having similar properties to cold molasses. Heating bitumen improves its adhesiveness, and simplifies transport and storage logistics by allowing it to flow more like a liquid.
In this article, we will cover why bitumen is heated, what temperatures bitumen must be heated to, and how to heat bitumen in bitumen tank containers.
Why Heat Bitumen?
In its natural state, bitumen is thick and viscous. Heating bitumen transforms the product into a less viscous liquid state, allowing for easier flow and recirculation. Compared to cold bitumen, hot bitumen has increased adhesive properties, improving the performance and usability of the substance.
What Temperature Should Bitumen be Heated To?
Two key factors must be considered when heating bitumen, the temperatures at which the properties of bitumen change, and the temperatures that ensure safe handling and consistent quality of the product.
For optimal performance, bitumen must be heated and maintained at specific temperatures. The type and grade of bitumen influence the recommended temperature, the higher the grade, the higher the temperature. In it’s most popular use of road construction, the recommended temperature ranges from 130-170OC.
When it comes to the safe handling of bitumen, Eurobitume provide technical guidance to ensure the safety of those working with the product. The maximum handling and storage temperatures vary according to grade again, but currently, bitumen and air-rectified bitumen should not be heated above 200OC, and severely oxidized bitumen should not be heated above 230OC, in part due to the emissions released.
The rate at which bitumen is heated is also important, as the thermal energy must be allowed to transfer away from the heater tubes without causing over heating in the product surrounding the tubes.
How is Bitumen Heated In Tank Containers
The requirement for bitumen to be heated results in the need for bitumen containers to have inbuilt heating tube configurations. There are three options to heat the containers, direct fire burners, electric element heating, or thermal fluid/steam heating, with TEC’s BitutainerTM Range ensuring high thermal efficiency in all tank variations.
Direct Fire Burners
Using direct fire burners is the most popular method to heat our BitutainersTM, powered by diesel, biodiesel or gas, the burners heat up the flame tubes running through the tank, which transfer the heat evenly and safely to the surrounding bitumen. TEC’s direct fire burner sets can heat a 20ft Shipper BitutainerTM in approximately 10 hours.
Electric Elements
Electric
elements utilise an electric resistant assembly to heat the bitumen in the
tank, removing the need for heating fuels. This method of heating is ideal for
product temperature control, where the bitumen must be gradually heated and
maintained at a consistent temperature. Differing
heating elements can be used for different applications, with metal rod assemblies
being robust and durable enough for transportation where frequent handling is
required.
Thermal Fluid or Steam Heating
Thermal fluid or steam heating is often the preferred method of heating in large-scale storage applications due to its efficiency and capability to heat large volumes using one centralised boiler. The tank is fitted with a heating coil, which transfers the heat from the thermal oil or steam to the surrounding bitumen in a controlled and gradual manner. Although well suited to fixed storage applications, when the tank is being used for transport and is frequently disconnected from the boiler, the pipeline requires bleeding upon reconnection to ensure there is no air in the system, adding complications to the transportation of the tank.
Contact us to find out more about thermal fluid or steam heating options.
Bitumen heating is essential for transportation and storage logistics, both to simplify procedures and improve performance of the end product. TEC’s BitutainerTM range has been designed to improve thermal efficiency, with our range of tanks having various options to accommodate your heating requirements. Contact us today to find out how TEC can improve the thermal efficiency of your bitumen operations.
