Transporting viscous food-grade bulk liquids like honey, molasses, syrups, and fatty acids requires meticulous preparation to ensure the shipment reaches its destination without compromising quality. These viscous liquids demand specific considerations due to their sensitivity to temperature changes. In this article, we’ll explore how bulk freight professionals address these temp changes by relying on in-transit heat and/or steaming during the transport process.
What are the temperature concerns with viscous liquids?
Shipping viscous bulk liquids that are temperature sensitive differs significantly from handling other commodities. These viscous products often require heated transport to prevent solidification and to maintain fluidity.
If such a product goes below the required delivery temperature during transport, chances are it may require outside steam to heat the material up to the temperature needed for offloading.
- Difficulty in Handling and Processing: Solidified liquids or liquids that have lost their fluidity are challenging to pump, pour, or measure, which complicates unloading and processing at their destination. This can lead to delays and additional heating costs to return the product to a flowable state.
- Quality and Consistency Issues: Repeated melting and solidification cycles can potentially affect the texture, color or other quality attributes of a liquid product, especially if it's intended for cosmetic or food-grade applications where consistency is critical.
To help combat solidification, in-transit heat is often used during transport.
What is in-transit heat?
The main purpose of in-transit heat is to maintain a product’s viscosity so that it is acceptable for unloading. Bulk liquid tankers with in-transit heating capabilities have a series of steam coil lines that run along the floor of the tank. The truck heats and circulates coolant through these lines in a continuous cycle. When running at full strength – typically after 4 hours of continuous driving – this system will reach optimal full capacity working to maintain temperatures of materials that are rated for unloading at 150˚F or below.
Importantly, this in-transit system does not actually heat the liquid in the tank. Rather, it assists in maintaining the product’s temperature. In other words, it seeks to minimize the loss of heat during transit.
For example, let’s say there is a viscous product like molasses that will begin to solidify at 90˚F. It is going to be loaded at 115˚F and needs to be delivered at or above 100˚F. Upon its loading into a stainless-steel tank, its temperature – and this is true of any heated liquid product – will most likely drop.
Depending on the variables involved, however, this temperature drop can be even more significant. These variables include the ambient/outside temperature, the tank temperature prior to loading (i.e., was the tank warm after just being washed?), and the amount of material vs air/empty space in the tank.
From there, the in-transit heating system will try to maintain that temperature throughout the journey. The driver will call into dispatch each morning of the journey to report the temperature.
Even with the system running as designed, there still is the possibility the material could drop in temperature. If it is clear over the course of these temperature readings that the product may fall below the required temperature prior to delivery, then outside steaming will be needed.
What is steaming?
Tank steaming occurs at most tank wash stations as well as other facilities (e.g., railyards). Such facilities have steam lines that connect a boiler to an external hook up of the tank’s coil heating system (only after the tanker’s lines have been flushed out if the in-transit heat system was charged). Once this connection is made, the boiler system will apply and build pressure through the steam lines before releasing it.
A “steam trap” is a mechanism on the back of the tanker which allows low pressure to build up and slow the steam as it progresses through the coils, which allows for better transfer of heat to the tank.
Ideally, the tank will be heated to a temperature above the required delivery temperature so that the driver has a “buffer” to allow for natural temp decreases. Steaming must be performed carefully as you can scorch the product by applying too much steam too quickly.
Key Considerations
What is the actual loading temperature of the product? The ideal scenario is that the actual loading temperature is sufficiently high so that it arrives at the required delivery temperature. This is to account for the loss of heat that will occur during loading and transport.
If the product is not loaded hot enough, a stop for steaming will need to be included in the route.
What is the travel distance of the shipment? The longer the trip, the more likely it is that the temperature of the product will drop during transit.
How much air/empty space is in the tank? Think of a thermos. If that thermos is full of liquid, the liquid will stay hot for a day or more. If it’s not full, however, and there’s a fair amount of empty space, the liquid will cool down more quickly. The same applies to bulk liquid freight. A tank that is completely full of liquid is going to retain heat much more effectively than a tank that has a lot of empty space.
Is in-transit heat necessary? In our experience here at Bulk Connection, in-transit systems are of little benefit when dealing with delivery temperatures that exceed the system’s maximum 150˚F-160’F output. For these hotter temperatures that can’t be assisted by in-transit systems, a mixture of loading at a sufficiently high temperature and steaming, if necessary, is the best approach.
Lean on Bulk Connection for viscous bulk liquid transport
Given the complexity of shipping temperature-sensitive viscous liquids, partnering with a bulk freight partner that specializes in shipping these products is vital. With decades of experience and a deep understanding of the intricacies involved in transporting viscous food-grade products like honey, molasses, syrups, and fatty acids, Bulk Connection is uniquely qualified to ensure your shipment is managed with the utmost care from start to finish.
By focusing on precise temperature control and deploying the right equipment and strategies, Bulk Connection can ensure that your viscous bulk liquids arrive at their destination in optimal condition, preserving their quality and consistency. To learn more about our bulk freight capabilities, contact us today
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