How is heat transfer oil heated?

In many areas of industrial production, thermal oil heating systems play a crucial role due to their high efficiency and stability. So, how exactly does thermal oil achieve the heating process? Below is a detailed explanation.

I. Heating Principle
Temperature transfer oil, also known as organic heat carrier or heat transfer medium oil, is an intermediate heat transfer medium with excellent thermal stability and low vapor pressure. Its heating principle is based on heat conduction. When heat is applied to the thermal oil, the oil molecules gain energy, their movement intensifies, and collisions between molecules cause heat to gradually transfer throughout the oil.

Taking a common electrically heated thermal oil furnace as an example, the core component of this device is the electric heating unit, mainly composed of heating tubes or heating elements. When current passes through these heating elements, heat is generated due to the resistance effect, and electrical energy is directly converted into heat energy. The thermal oil absorbs this heat, its temperature rises, and due to its good fluidity, it can quickly transfer heat to the area that needs to be heated.

II. Key Components of the Heating System

Heating Element: In addition to the electric heating elements mentioned above, the burner is the key heating element in heat transfer oil heating systems using coal, heavy oil, light oil, or combustible gas as fuel. The burner releases a large amount of heat by burning fuel, which is absorbed by the heat transfer oil.

Circulation Pump: The circulation pump is the power source of the entire heating system. It is responsible for driving the heat transfer oil to circulate within the system, delivering the high-temperature heat transfer oil that has absorbed heat to the heat-using equipment to meet the heating requirements of the production process; simultaneously, it returns the cooled heat transfer oil flowing out of the heat-using equipment to the heating area for reheating, forming a continuous and stable circulation to ensure uninterrupted heat transfer.

Temperature Control Device: The temperature control device plays a precise regulatory role in the entire heating process. Temperature sensors monitor the temperature of the heat transfer oil in real time and feed the data back to the controller. The controller compares the preset temperature value with the actual measured temperature and automatically adjusts the power of the heating elements. For example, when the actual temperature is lower than the preset value, the controller increases the power of the heating element to make the heat transfer oil heat up faster; conversely, when the actual temperature is higher than the preset value, the controller reduces the power of the heating element to prevent the heat transfer oil temperature from becoming too high.

III. Heating Operation Procedure
System Preparation: Open the inlet valve and the inlet valve of the heat transfer oil heating system, and close the outlet valve. Inject an appropriate amount of heat transfer oil into the system and start the circulation pump, allowing the heat transfer oil to circulate in the system in a cold state for 1-2 hours. Check whether the circulation is normal and ensure that there are no leaks or other abnormalities in any components.

Heating Operation: Start the heating device and begin to heat up slowly. During the first use, the heating rate must be strictly controlled, generally at a rate of 10 degrees Celsius per hour. When heating to 80-120 degrees Celsius, this stage is the dehydration stage, and the pressure gauge of the heat pump must be closely monitored. If the pressure gauge fluctuates, it indicates that moisture is evaporating in the system, causing pressure fluctuations. Heating should be stopped immediately, and the temperature maintained for a period until all moisture is expelled and the pressure stabilizes. Afterward, the temperature can be increased at a rate of approximately 20 degrees Celsius per hour. When the heat transfer oil temperature reaches 180-220 degrees Celsius, this stage is the light component evaporation stage, which also requires temperature control for a period before the temperature can be further increased to the operating temperature for normal use.

Operation Monitoring: Throughout the heating process, operators must continuously monitor the system's temperature, pressure, flow rate, and other parameters to ensure they remain within normal ranges. Regular checks of the equipment's operation should also be conducted, looking for leaks, abnormal noises, etc.

Stopping Heating: After the heating task is completed, first turn off the heating element to stop heating. After the heat transfer oil temperature has appropriately decreased, turn off the circulating pump, and finally close the heat transfer oil inlet valve. Clean any residual heat transfer oil from the heating system to prepare for the next use.