Electric circulation heaters are very versatile and useful process heaters. Common applications will flow liquids or gasses through the heater and provide very stable reliable temperatures for these processes. The exchange of heat is dependent upon the liquid flowing, the flow rate, and the residence time or time through the heater.
Many critical processes require heat to be created and passed to the process. Most of these are flowing, and the tried and true method of doing this is with a shell and tube heat exchanger. In the example above, the fluid to be heated is pumped or otherwise pushed into the vessel. Inside of the vessel are tubes. These tubes have a product flowing through them (heat transfer medium) that is heated. When the fluid flowing through the vessel contacts the tubes with a heated medium in it, the heat of the fluid is increased (or decreased if you are cooling the fluid).
Fluids and vapors
There are many types of fluids and vapors that can be passed through the tubes to heat the tank fluid. Steam, glycol/water, hot oils, water, just to name a few. The management of these fluids involves a great deal of equipment. It is a tried and true method of heating many processes. There are many different styles of this type of heat exchanger as well.
Electric heat exchangers have electrically resistive wires inside of the tubes (Called electric heating elements) that create heat. Temperatures can range from -260F to as high as 2500F. Electric heating elements are very efficient at transferring heat to the product flowing through the vessel. When voltage is applied to the resistor within the heating element, heat is created. Transferring this heat to a process is just as easy as it is with a heat exchanger.
Heat exchangers
Heat exchangers rely heavily on the indirect heating of the heating medium
The product requiring the heat is passed over the elements. Temperature sensors verify both the process temperature, and the temperature of the heating elements to make sure that it does not get too hot.
Heat exchangers rely heavily on the indirect heating of the heating medium that they need in the process. No matter the medium, the process, or the temperature, there are a certain amount of btu’s required (btu= the amount of energy required to heat a product). Once a process can define the needed btu’s, many heating methods can be considered to do that job. Electric circulation heaters should be considered for this job.
Several reasons
There are several reasons why-
- The heat created by an electric heater produces no Nox Emissions. If the company has a sustainability or green initiative, looking into converting your process to an electric source of heat could help users to meet those.
- Electric heat is 100% efficient- or so they say. Think about it…every ounce of electricity is converted into heat- so… 100%.
- Electric heating control systems have nearly an infinite turn down ratio. If the system needs to run at 8%, that’s all to pull power wise. Sampling rates can be as often as 6 times per second, and with the proper power control system, outputs can be adjusted faster than that (as fast as 1/120th of a second if the sampling rate could keep up!). Users' will only pull the amperage that is needed to keep the system running.
- Much easier to maintain. No steam, steam lines, or steam traps. No heat transfer fluids or expansion tanks or condensate return lines. Just push the liquid or gas through the heater chamber and into the process.
- Redundancy is a big factor. Many of the users' are familiar with the concept of building redundancy into the pumping systems as one example. Two pumps are installed for one duty. When one goes down, users' have one 100% spare. That way they can work on the other unit while the system is still running. The same can be designed for electric circulation heaters…by designing 2x the capacity in the heater itself, or by having a second heater.
- Higher heat flux can be achieved by an electric heater. Users' have to be careful here though as higher heat flux or what is referred to as watt density on electric heaters can be harmful to both the electric heater and the process. PowerPro by Powerblanket experts can help them through that process.
