Last updated on January 20th, 2023 at 03:35 pm

When oil freezes, it creates a damaging and potentially destructive scenario for process engineers. Salvaging frozen oil isn’t feasible, and the cost of waiting for it to thaw is high. These realities make frozen oil a problem that’s better to prevent than “cure.” Fortunately, a combination of freeze protection protocols and an over-the-side (OTS) heater can prevent oil from freezing, especially for outdoor oil tanks. 

Effects of frozen oil 

Oil becomes cloudy in temperatures below 35 degrees Fahrenheit (1.6 degrees Celsius) and crystalizes below 20 degrees Fahrenheit (-6 degrees Celsius). When crystals form, they cling to the fuel line, which, in turn, slows down the flow rate of oil. Crystallization will also shut off the heating system entirely. When the heating system fails, the oil doesn’t freeze completely but turns into sludge, leading to adverse downline effects. 

Consequences of frozen oil 

• Lost production time:  Frozen oil is unusable oil. A lack of flow halts production and can only resume when oil returns to its natural form or gets replaced. 
• Income & profit losses: A natural extension of lost production is a loss of income and earnings. After all,  poor oil flow means customers can’t receive their products on time or at all. 
• Loss of trust: Poor oil production and product loss can lead to a loss of confidence from customers. 

In most cases, freezing occurs in oil tanks located above or below ground in cold climates. A good example would be an oil processing station in a northern state or province between November and March.

An immersion heater can help counteract the effects of cold weather on oil, namely, an over-the-side heater. We design our over-the-side heaters to be portable and mobile so they can fit on the top or the side of any tank. For heaters placed at the top of the tank, the pipe submerges in the liquid and heats it directly. Regardless of its orientation, the heater will deliver uniform heat to keep the oil warm enough to prevent sludging.  

Freeze protection protocols

The delicate properties of oil make it a challenge to restore once frozen. Applying forced heat to frozen oil can result in thermal degradation, which will destabilize the end product. Certain oils will degrade twice as quickly once they’ve surpassed their base activation temperature, rendering them unusable if the degradation continues. 

That’s why operators have to allow ambient heat to thaw the oil, so it regains its viscosity. But this process is usually time-consuming and challenging in frigid environments where natural heat is hard to come by. These challenges make freeze prevention all the more vital. 

How does an OTS heater help prevent oil freezing?

We designed our over-the-side heaters specifically to heat viscous fluids adversely affected by cold temperatures. With the heater inserted on top or to the side of the tank, its elements transfer electrically generated heat to the inner wall of the pipe. This happens either through convection or radiation. 

The watt density of the OTS heater is set to match the type of oil and size of the tank, so it doesn’t overheat the oil in the process. In some cases, it may be necessary to attach more than one heater. 

Additionally, we recommend adding temperature control panels, so operators can adjust the temperatures of the oil more precisely. More precision lets operators sustain temperatures that prevent their target fluid from under or overheating. 

Over-the-side heaters also allow for complete customization. We build them to fit the unique shape and orientation of the oil tank and fit them with heater element materials best suited to heat your target oils. Additionally, we can add protective coatings and sheaths to prevent corrosion of the heaters. 

Other oil freeze prevention protocols

An over-the-side heater is a powerful tool in a freeze-prevention arsenal, but there are other factors to consider. Heat loss, for example, can still occur regardless of how many heaters you attach to a tank. If heat loss is significant, a heater loses efficiency because it delivers heat that essentially disappears. 

There’s also the type of oil. Depending on the oil’s grade and composition, it may be more likely to cloud and crystalize regardless of how much heat it receives. With these factors in mind, there are some other preventative measures to take. 

Non-heating solutions to prevent oil freezing

• Insulate your fuel lines. Adding insulating materials to fuel lines will help prevent natural heat loss. The oil will remain at its ideal temperature with more heat in the lines, so you don’t need to increase the heater’s output. Think of this as a greenhouse effect of sorts. 

• Consider using blended oils. Certain oils tend to cloud and freeze easier due to their molecular composition. Blended oils typically fair better in cold temperatures, making them ideal for specific applications. 

• Move your lines underground or indoors. If tanks and fuel lines are movable, shifting them to a warmer location can do wonders to keep the oil viscous. The natural ambient heat of a sheltered facility will offset the effects of cold weather from the outdoors. Of course, relocating your tanks and lines may not be possible, and for such instances, we recommend adding an over-the-side heater. 

Installation of OTS heater for outdoor oil tanks

For many oil operations, combining an over-the-side heater with freeze-prevention protocols is ideal for preventing oil sludge. The decisions around these measures will vary based on production schedules, budgets and customer needs. Also, mathematical calculations concerning power output and heat loss will likely influence what measures you choose or forgo. 

However, if you need an over-the-side heater, you can rest assured that our selection can help heat your oil applications effectively. That includes customized solutions to suit the unique settings and conditions affecting your oil operations. Best of all, we offer guidance on what features your particular heater will need to support your application.  

Get a quote for your over-the-side heater today. Our representatives will help you find the exact setup needed for your industrial needs.