Tank heating systems are often critical to most industrial applications, particularly with temperature control maintenance. For example, caustic tanks provide critical feedstock to refineries, chemical plants and processes. Biodiesel feedstocks such as vegetable oils, animal fats, palm oils or even jatropha will solidify at relatively normal ambient temperatures, requiring process temperature maintenance to ensure product quality. Keeping this product warm is vital to keep processes running efficiently and preventing product spoilage.
Electric tank heating systems can be designed to heat up tank contents from a lower to a higher temperature, or they can be designed to simply maintain a temperature once it is reached.
Process Temperature Control
Many products and material arrive on site preheated from its source of delivery. Knowing what your products can tolerate on the low end of heat is critical. Spoilage will lead to longer production times and higher costs on your end. How low can you go before the product cannot be used in your processes?
It’s good practice to have a plan for both how you intend to warm up materials and how you intend on maintaining a consistent temperature. These process temperature maintenance plans are generally composed of two items: insulation and heating equipment.
Insulation
Thermal insulation is an important component of a temperature maintenance system. The type of insulation and its thickness plays a key role in keeping heat at a stable level within your processes.
Heater selection
Heater selection is also a factor. Tank heat can be maintained by heat trace, steam coils, heating pads or immersion heaters. Each has their own specific advantages for your application and should be a part of your process temperature maintenance plan.
Tank Heat Up
Tanks will often hold product that need to be heated up. A new load of product that is below the desired temperature for tank contents could be dumped in and, as a result, lower the average temperature. Just as with tank maintenance applications, the thermal insulation system is critical so that you don’t lose what you already have. All methods of heat up must provide dependable heat up.
Of primary consideration is how quickly you want to heat a tank to temperature. If you go too quickly with the wrong heating system, products can become burned or cook themselves onto the heating system.
Since it will take 8-10x as much thermal energy to heat product in a tank up to temperature, compared to maintaining temperature, you should also consider using higher 3 phase voltage. In the U.S., most heating systems are available in 480V 3 phase. This will drastically reduce your amperage requirements which will translate into much lower costs than if using lower single phase voltages.
Heater Types and Placement
As previously stated, your process temperature maintenance plan needs to be specific and use the right type of heater that best fits your processes. Common heater types used to heat up a tank are heat trace, steam coils, heating pads (for smaller systems), and immersion heaters that are specifically designed for tank heating.
Sensor placement in tank heaters should be carefully considered when designing a system. Level controllers should be interlocked with the heater control panel to shut the heater down in low level conditions. Heater over temperature sensors should be installed on the heater sheath when using an immersion heater so that the heater is not allowed to run up to a high temperature, as this could cause damage to the tank or its contents.
Finally, the main temperature sensor that regulates the heater must be placed at or just above the heat source. Placing it up high in the tank or far away from the heater will not allow the heater to perform as intended.
Control Panels and Wireless Systems
Control panels should be designed to allow for interface with the tank level, temperature systems, and remote plant control monitoring systems. Modern advances have allowed for a much wider acceptance of wireless communication systems as well. Both temperature and level information can be transferred to the heater panel wirelessly. Data transfer from the control panel to the plant-wide control system will allow tank heating systems to report to the proper personnel regarding performance and reliability.
Create a Heat Plan
Powerblanket can help you decide on a heat plan that meets your temperature-specific needs. Our team of thermal engineers are always available to talk over options and choose what is best for your processes. Reach out to us here.
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