Thermal Oil Boiler Safety and Energy Saving |Thermal Oil Boiler Scaling Causes, Hazards and Solutions

January 27, 2022

Compared with traditional heating methods, thermal oil boilers have the advantages of energy saving, uniform heating, high temperature control accuracy and low operating pressure, and are widely used in heating systems. However, some problems existing in thermal oil boiler have always plagued business operators, among which the scaling of thermal oil boilers is a major problem.


The scaling of the thermal oil boiler system is actually the coking and carbon deposition of the thermal oil, so why does the thermal oil boiler scale?


Thermal Oil Boiler System Scaling Causes


1. During the circulation process of the high-temperature thermal oil, some colloids are produced;


The high temperature thermal oil circulates and transmits heat energy in the hot oil furnace, and generates gelatin at the same time. The colloid is viscous, and good quality thermal oil can suspend the colloid in the oil. During the circulation process, part of the colloid can be filtered out through the filter. However, if there is a small part of the glue attached to the inner wall of the furnace tube, it is easy to coke.


2. Degrade and polymerize with the incoming air;


In the process of thermal oil circulation, if there is air, it is easy to degrade and polymerize, forming low boilers and high boilers. Low boilers can be discharged into the atmosphere through the high-level tank, while a small amount of high boilers can be dissolved in the thermal oil. If the solubility of the thermal oil reaches a saturated state, the high boilers will adhere to the inner wall of the tube, which is another cause of coking. reason.


3. The operating temperature exceeds the design temperature;


Operating temperatures above their design temperatures can cause autocatalytic thermal decomposition, resulting in coking in the tubes.


4. The leakage of process materials is brought into the thermal oil system;


The leakage of process materials is brought into the thermal oil system to form corrosion products and rust; and the contamination of impurities brought in during maintenance will cause coking on the inner wall of the pipe.


5. The thermal oil may have the tendency of coking and carbon deposition during use;


The main reason for the increase of carbon residue is thermal polymerization reaction, which occurs due to the thermal dehydrogenation of the thermal oil during the operation of the heating system.


6. The acid value of thermal oil increases;


The thermal oxidation reaction occurs when the thermal oil in the expansion tank of the open heating system contacts the air or participates in the circulation, resulting in the formation of viscous substances such as gum and asphalt, forming coking. In addition, the thermal oxidation reaction also produces acidic substances, which can cause corrosion and leakage of equipment.


Thermal Oil Boiler System Scaling Hazards


■The scaling of the thermal oil pipe reduces the flow cross-sectional area of the oil pipeline, increases the friction force, and increases the energy consumption of transportation;

■The formation of a thermal insulation layer leads to a decrease in heat transfer efficiency, an increase in exhaust gas temperature, and an increase in fuel consumption;

■Due to the requirement of production process temperature, the temperature difference of heating furnace tube wall will rise sharply. If the temperature difference between the inside and outside of the furnace tube is increased to 600-700℃, it is easy to burn through the furnace tube, form a bulge, and cause a fire accident.


Thermal Oil Boiler System Scaling Preventive Measures


1. Choose the ideal thermal oil boiler system supplier

①Choosing a professional thermal oil boiler complete system supplier 

It can ensure that the quality of thermal oil is guaranteed. They have a complete supply chain, which can save intermediate links and directly reduce procurement costs.

②Choose a large-scale manufacturer with more than ten years of establishment

The supporting service providers selected by large manufacturers have R&D and quality monitoring capabilities. Although the unit price is high, the quality after use is stable and the risk is reduced.

③Choose a manufacturer who can provide comprehensive technical services

Choose a supplier who can provide comprehensive technical service capabilities of the system, professional technical service advantages, and can meet the needs of end customers for technical support in the whole process.

2. Choose the right thermal oil

Pay attention to the maximum operating temperature, thermal stability, sulfur content, chlorine content, carbon residue, acid value, grayscale, moisture and other important indicators of thermal oil.

3. Prevent the scaling of the thermal oil heating system in daily work

①Overload and operation beyond the design value are the fundamental reasons for the fouling and coking of the thermal oil, so the operating conditions should be kept stable.

② Regularly clean the filter screen in the oil circuit to remove impurities in the thermal oil and prolong the service life of the thermal oil boiler.

③ Regularly check the physical and chemical indicators of the thermal oil, and restore the oil quality of the thermal oil by changing the oil to ensure the performance of the thermal oil.


Eight Tasks to Achieve Safety and Energy Saving in Thermal Oil Boiler


①Long-life, energy-saving thermal oil and high-quality thermal insulation materials should be selected to achieve safety and energy saving from the source.

②Select boiler workers with "organic heat carrier boiler operation qualification". The general boiler workers learn how to use steam tin furnace, which is essentially different from the use of thermal oil (organic heat carrier) furnace.

③ The boiler workers are required to climb to the high tank every month to check whether the oil level is within the allowable range, and whether the oil level and oil temperature monitoring devices are normal. More than half of the accelerated aging of the thermal oil is caused by the lack of oil in the high tank.

④ Regularly sample and analyze the thermal oil every year, replenish the thermal oil regularly, and ensure that the performance index values are controlled within the standard range. If important indicators are found to be substandard, repair or replace them in time.

⑤ The boiler workers operate in strict accordance with the operating procedures, and the circulating oil pump is not allowed to stop until the oil temperature of the thermal oil drops below 80 °C.

⑥Check whether the pipelines, valves and oil pumps are properly used and sealed every month. Beware of oil seepage and leakage, which may cause fire in serious cases.

⑦ Pay attention to repair and replace the insulation material in time. Practice has proved that at least 10% of the energy loss is lost due to the low insulation performance during the pipeline transportation.

⑧ Boiler workers keep operation records every day, and management personnel make monthly statistics on fuel consumption, so as to be well documented.



The installation of thermal oil boiler and piping system is a complex and systematic project, which often requires the cooperation of several suppliers, including boiler manufacturers, boiler installation companies, thermal oil suppliers, and thermal insulation material suppliers. It may lead to the existence of safety hazards or a large amount of waste of energy. EPCB has been specialized in boiler system research for 68 years, truly standing in the customer's position, saving every penny spent on boiler system for customers!


EPCB, your boiler system expert!

Further Reading:

Boiler Energy-Saving Technology | Waste Heat Resource Recovery and Utilization

Boiler Energy-Saving Technology--Boiler Water Pump Power-Saving Transformation

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