Waste Oil Heaters

Waste Oil Heaters

Waste oil is initially believed as an excessive synthetic product that should be disposed. Waste oil is obtained from various sources, for example, from automobiles engines, industrial lubricating oils [1], vegetables waste, etc. However, by removing the oil by-product from a production process will not only cost a heavy disposal expense but the company is also subjected to an environmental cost depending on the concentration of pollutants emitted to the environment.

Instead of increasing the contaminants of the city’s water supply and harm the ecosystems, why not convert the waste oil into a free heating resource? The potential of waste oil is often underestimated and this by-product could lower a large sum of unnecessary expenses for the company [2]. Burning waste oil can recycle a very useful resource and at the same time to reduce the operating costs. Applications of recycled oil include motor oil, furnace fuel, aluminium rolling oil, lubrication, etc. [3]. Those products are obtained by the re-refining process which repeats the original refining process but instead with waste oil as the input. The essential step of the refining process is to burn the waste oil by heat.

Burning oil heater does not need expensive equipment or process to achieve. The heating process can be achieved by a single step with an electric oil heater. There are various types of fuel oil heaters that can be used for waste oil burning, for example by circulation heaters (also known as in line heaters) or immersion heaters. A circulation heater is generally recommended for oil application in production industry. This type of fuel oil heater does not only increase the liquid temperature but also increase the mobility of the fluid by the circulation flow. The circulation maintains the oil viscosity so that the liquid output from the heater continuously flows to a process pipeline.

The uses of waste oil heaters

Figure 1 – Internal & External View of the Circulation Heater

A circulation fuel oil heater consists of a cylindrical casing enrobing a flange immersion heater along with two nozzles for inlet and outlet (See Figure 1). The inlet fluid enters the waste oil heater via the threaded nozzle and the liquid is then heated by the heating elements before exiting to the process pipeline that can be joined to the fuel oil heater outlet. Insulation around the steel casing is used to prevent heat loss to the ambient environment and to ensure the maximum heat transfer for the circulating oil.

The heating source generates from the heating elements tubes which are hold by a steel flange. A heating element tube consists of a Nickel Chromium resistor wire enrobed by a protective sheath material and Magnesium Oxide powders (See Figure 2). To achieve the maximum performance of the waste oil heating, the recommended sheath material would be Incoloy™. The heating process initiates from the resistor heat dissipation and the heat distributes around the surface of the heating elements. As a result, the heat is evenly distributed to the entire fuel oil heater. As the flowing waste oil enters the heater, the heating elements increase the fuel oil temperature rapidly by direct heating, and then the heated oil exits the electric oil heater outlet stream.

Figure 2 – Cross Sectional View of a Heater Element Tube

For smaller scale waste oil heating, a single flange immersion heater can be used for oil storage tank or vessel. The heating process is similar to the circulation heater, but without the use of a steel casing, the storage tank containing the oil is directly heated by the immersion heater (See Figure 3). The immersion fuel oil heater is recommended for stationary or small volume waste oil heating.

There are other types of electric waste oil heaters to consider depending on the target industry. The shapes and materials of the electric oil heaters can be customized to fit the target application. WATTCO™’s technical consultants are always available to assist the clients to select the best heater for the desired application whether the oil heating is for small or large operation.

Figure 3 – Sketch of a Flange Immersion Heater for an Oil Storage Tank

Figure 3 – Sketch of a Flange Immersion Heater for an Oil Storage Tank


1.       U.S. Environmental Protection Agency. “Chapter 1: External Combustion Sources.” Compilation of Air Pollutant Emission Factors. 5th ed. Vol. 1. Research Triangle Park, NC: U.S. Environmental Protection Agency, 1995. 1.11-1. <http://www.epa.gov/ttnchie1/ap42/ch01/final/c01s11.pdf >