1. Hazard of Deteriorated Thermal Oil Quality 

Premature deterioration of thermal oil quality due to poor production process operation management is one of the most common problems in electric heating thermal oil furnaces. Some thermal oils show severe degradation in performance indicators after only one or two years of use. Long-term operation with degraded thermal oil leads to increased carbon deposition on the heating surface tube walls, reduced inner diameter causing decreased thermal oil flow, increased resistance for the circulating pump, and continuously reduced heat transfer efficiency, eventually resulting in coking, blockage, and serious accidents such as overheating, deformation, and tube rupture. One cause of thermal oil quality degradation is local overheating leading to thermal cracking, and another is oxidation of the thermal oil. When the thermal oil exceeds its specified maximum operating temperature, local overheating occurs, causing thermal decomposition and polycondensation, precipitating carbon residue, lowering flash point, darkening color, increasing viscosity, reducing heat transfer efficiency, and leading to coking and aging. Contact between thermal oil and oxygen in the air causes oxidation reactions, generating organic acids and polycondensing into sludge, increasing viscosity, not only reducing the service life of the medium but also causing acidic corrosion in the system. Currently, domestic thermal oil manufacturers have different quality standards, and the quality of produced thermal oils varies greatly. For thermal oil in use, the "Safety Technical Supervision Regulations for Organic Heat Transfer Material Heaters" stipulate that kinematic viscosity, flash point, carbon residue, and acid value should be tested at least once a year. 

2. Hazard of Automatic Control System Failure 

  Currently, the status of domestic thermal oil electric heater technology is that the thermal oil control system uses a programmable logic controller (PLC) as the control core. Thermal oil at a certain temperature enters the heater from the inlet under the working pressure of the circulating pump, passes through the heating chamber of the heater to gradually increase temperature, and then flows out from the outlet, thereby achieving the required process temperature, further improving the automation level of the equipment. 

  In the control system, the thermal oil is sent into the entire system through a gear pump. When the preset magnetic flip column level controller reaches the specified level, the gear pump automatically shuts off. Then the circulating pump and electric heater start to heat. When the outlet oil temperature reaches the set value, it enters the user system for circulation. After being used by the equipment, the oil returns to the device for heating again, repeating the cycle, which is the working state of the thermal oil. 

These automatic control systems are effective checkpoints to ensure the safe operation of electric heating thermal oil furnaces. However, it is often these checkpoints that fail during actual operation due to weak safety awareness or economic reasons. 

3. Hazard of Air and Moisture Ingress 

During new oil filling, oil change, and maintenance of electric heating thermal oil furnaces, air and moisture can easily enter. During heating, this air expands and moisture evaporates, with volume changes far exceeding the thermal expansion of the thermal oil itself. When the relative pressure is zero, the volume expansion of water evaporation is about 1600 times its original volume, and air expands about 5 times when heated to 270°C. If these air and moisture are not discharged in time, they will cause an increase in operating pressure, seriously threatening system safety. Therefore, the moisture and other components in the thermal oil should be strictly controlled. During the heating start-up process, the vent valve should be repeatedly opened to discharge the mixed vapor of air, water, and thermal oil from the system, and attention should be paid to controlling the heating rate of the thermal oil. 

← Previous
Electric Heating Oil Furnace - Thermal Oil Heater Next →
The Value and Role of Low-Temperature Heat Transfer Oil