In the field of industrial heating, thermal oil boiler plays a pivotal role. With its efficient, stable and safe heating performance, it has become an indispensable equipment for many industries. In this article, we will analyze all aspects of thermal oil boilers, answer key questions such as why it is not the same as other heating systems, to present you with a comprehensive and professional knowledge system of thermal oil boilers.
A thermal oil boiler is an industrial heating system that utilizes a heat transfer fluid, usually thermal oil, to generate and distribute heat. It works by circulating thermal oil through a heat exchanger to absorb heat from a combustion source such as biomass, natural gas, light oil, or waste-derived fuel. The significant advantage of thermal oil boilers over some other heating systems is their ability to reach high temperatures without being subjected to high pressures. This feature makes it a versatile and safe solution for a variety of industrial applications such as the chemical industry, the chemical fiber industry and new energy sources.
The fuel is fed into the fuel storage hopper in front of the combustion chamber, the chain feeder feeds the fuel into the combustion chamber, and at the same time the air supply fan operates to supply air into the combustion chamber to enable the fuel to burn. The combustion of the combustible fuel produces high temperature hot flue gases, which are transported to the oil furnace. In this process, the adequate combustion of the fuel depends on the supply of the right amount of air, and the role of the blowers is crucial.
The oil furnace is equipped with a heat exchange tube in the furnace body, in which the thermal oil flows while the hot flue gases from the combustion chamber flow outside the tube, thus heating the thermal oil inside the tube. After the heating process, the hot flue gas gradually loses its thermal energy and is sucked out by the fan and sent to the air heater at the rear of the oven. The hot flue gas enters the air heater and is used to heat the incoming air into the combustion chamber, warming up the supply air into the combustion chamber, which not only aids in the combustion of the fuel, but also improves the efficiency of the system. Finally, the hot flue gas exits the air dryer and enters the exhaust gas treatment system, where it meets the standards and is discharged by the induced draft fan through the chimney. The efficiency of the heat exchange process directly affects the performance of the whole heat transfer oil boiler system, while the design and arrangement of the heat exchange tubes are the key factors.
The cold oil in the equipment using heat is pumped back by the circulating oil pump and sent to the heating oil furnace body for heating, and then sent back to the equipment using heat. On the oil line, there is an automatic gas separation line, whose function is to separate the gas in the system, especially when there is no oil in the system and the oil supply system needs to run for a certain period of time to separate the gas. In addition, the system is equipped with an oil filling line, whose task is to replenish the system with oil and to ensure that the system is always full of oil and operates stably. The stable circulation of the heat transfer oil is the basis for a continuous supply of heat, while the gas separation and oil filling lines are important safeguards to maintain the stability of the circulation.
The design of the ash collection system depends on the type of fuel and the amount of ash to be collected. Fuel combustion produces ash, with a large amount of the bulkier ash being collected at the rear of the boiler. Lighter ash is carried by the flue gases out of the air dryer and exhaust gas treatment system and is collected in these facilities. Different fuels produce ash with different characteristics, so the ash collection system needs to be properly designed according to the actual situation.
The furnace chamber is the core component of the boiler where the combustion process takes place. Inside the combustion chamber, fuels such as natural gas, diesel or heavy oil are burned, releasing heat energy. This heat energy is then transferred to the heating coils that carry the thermal oil. The design of the chamber has a direct impact on the adequacy of combustion and the efficiency of heat transfer. Proper chamber dimensions and construction ensure complete combustion of the fuel and improved energy utilization.
Heating coils are a network of tubes located in the combustion chamber. These coils are arranged around the flame to provide a larger surface area for contact with the hot gases produced by combustion. Heat transfer oil flows through these coils and absorbs the heat generated by combustion. The number and arrangement of the coils vary depending on the capacity and design of the boiler. Properly designed coils allow the heat transfer oil to fully absorb the heat while ensuring that the pressure loss in the system is within acceptable limits.
In a thermal oil boiler, the burner is responsible for generating the necessary heat by burning a fuel, such as natural gas or oil, and transferring this heat to the thermal oil inside the heating coil. The performance of the burner directly affects the heating capacity and efficiency of the boiler. A quality burner can precisely control the mixing ratio of fuel and air to achieve efficient combustion.
This system consists of electronic components and sensors to monitor the operational performance of the boiler. It measures pressure, temperature and oil flow to ensure safe and optimized boiler operation. The advanced control system has the ability to automatically regulate and provide alarms. Through real-time monitoring and precise control, the control system ensures stable operation of the boiler under various operating conditions, improving the safety and reliability of the production process.
The oil pump is responsible for circulating heat transfer oil throughout the system. It must be able to deliver the oil to the coil at the correct flow rate and pressure. Given the high temperature characteristics of the oil, these pumps have been specially designed to operate properly in high temperature environments. The performance of the pump is directly related to the efficiency of the circulation of the thermal oil, which in turn affects the heating effect of the entire system.
These valves are used to regulate the pressure and flow of oil in the system and control the import and export flow of oil. Precise regulation of the control valves ensures that the pressure within the system is stabilized, ensuring that the heat transfer oil operates under suitable working conditions, thus improving the safety and stability of the system.
Expansion tanks are used to compensate for changes in oil volume due to thermal expansion. When oil is heated, its volume increases and if there is not enough room for it to expand, the pressure in the system will rise significantly. Expansion tanks allow the oil to expand without causing an excessive rise in pressure. Typically, expansion tanks are located higher than boilers and other equipment, which creates a static pressure in the oil circuit that keeps the oil liquid and prevents it from vaporizing. Another key function of the expansion tank is to replenish the oil. It acts as a storage vessel for heat transfer oil, ensuring that additional oil can be filled into the system when the oil level drops due to leakage or evaporation. Since oil is highly flammable at high temperatures, one way to prevent explosions is to inert the space above the expansion tank. This is accomplished through a process known as “capping,” in which an inert gas such as nitrogen is used to fill the upper space of the tank, preventing oxygen and air from entering. The proper design and operation of the expansion tank is essential to ensure the safe and stable operation of the system.
This type of thermal oil boiler usually has a small capacity and is often used in places with limited space. Due to gravity, hot oil is discharged faster in vertical boilers. For some production processes with high space requirements and relatively small heat usage, vertical thermal oil boilers are a suitable choice.
Horizontal thermal oil boilers usually have a larger capacity and higher efficiency than vertical ones. In a horizontal thermal oil boiler, it is easier to maintain and inspect the boiler components. Large-scale industrial production often requires a large heating capacity, and horizontal thermal oil boilers are able to meet this need, while their ease of maintenance reduces long-term operating costs.
These boilers use electricity to heat thermal oil instead of fossil fuels (such as natural gas or oil). In these boilers, a heating element generates the required heat to heat the oil. The heated oil is transported to different parts of the system in a closed-loop system to provide the necessary heat for the production process. Electrically heated heat transfer oil boilers do not use fossil fuels, reducing the emission of environmental pollutants. Due to the highly flammable nature of heat transfer oil at high temperatures, electrically heated heat transfer oil boilers are more suitable for lower capacity applications than gas-fired heat transfer oil boilers. In places where environmental requirements are high and the amount of heat used is not large, electrically heated heat transfer oil boilers have a clear advantage.
High specific heat capacity: able to effectively transfer heat to ensure that enough heat is absorbed and released in the heat exchange process.
High-temperature stability: to maintain its own properties stable in high-temperature environments, without decomposition or deterioration, in order to ensure long-term reliable operation.
Oxidation resistance: with the ability to resist oxidation, to prevent the formation of deposits in the system, affecting the heat transfer efficiency and normal operation of the system.
High boiling point: has a high boiling point to avoid vaporization at high temperatures and maintain liquid circulation.
Non-corrosive: does not cause corrosion to system components, extending equipment life.
Environmental safety: environmentally friendly, in line with relevant environmental standards.
Mineral oils are the largest category of heat transfer oils. They are obtained through the distillation of crude oil in refineries. Mineral oils have an operating temperature range of - 10°C to 300°C and are therefore suitable for temperatures below 300°C. They are more economical than synthetic oils. Mineral oils are more economical than synthetic oils and have a lower environmental impact. Paraffin-based and naphthenic oils are common examples of mineral oils. Mineral oils are a common choice of heat transfer oils in industrial applications where temperature requirements are low and cost is a concern.
Synthetic oils are produced through a chemical synthesis process. Synthetic oils, also known as aromatic oils, are based on a benzene structure. These oils have an operating temperature range of - 20°C to 400°C. Their aromatic structure makes them thermally more stable than mineral oils, making them suitable for temperatures higher than 300°C. At higher temperatures, synthetic oils offer higher efficiency and better heat transfer. Polyethylene glycol fluids, ester and diester compounds, and silicone-based oils are all types of synthetic oils. Synthetic oils are the ideal heat transfer oil choice for processes that require precise heating control at high temperatures.
Behran Heat Transfer Oil (Behran Hararat 32): has good thermal stability and thermal conductivity and is suitable for a wide range of industrial heating scenarios.
Shell Heat Transfer Oil S2: Widely used around the world with reliable performance to meet the needs of different industries.
TOTAL Theriola eta Thermal Fluid 32: recognized by users for its efficient heat transfer capability and stability.
Seminole thermal oil 66: excels in specific industrial sectors, providing stable heat support for production processes.
In the wood industry, thermal oil boilers play a vital role in the production of wood products. By using these boilers, the moisture in the wood is able to evaporate gradually in a controlled manner, which helps in improving the durability and stability of the wood. During the wood drying process, precise temperature control prevents the wood from cracking or warping due to rapid drying and ensures the quality of the wood.
Thermal oil boilers are the primary heat source for dryers and dyers in the textile industry. These boilers provide uniform and precise temperatures, which help to improve the absorption of dyes into fabrics and fibers and promote rapid drying of fibers. During the dyeing process, a stable temperature ensures color uniformity and dye fastness, improving product quality.
Heat transfer oil boilers are widely used in the chemical industry due to the high temperature and heat requirements in the production of products such as solvents, adhesives and resins. In addition, they are used in the production of asphalt, waterproofing membranes, bitumen and the heating of heavy petroleum materials. In chemical synthesis reactions, precise temperature control is essential for the conduct of the reaction and the control of product quality, and heat transfer oil boilers are able to meet this demand.
Thermal oil lubricates the thermal oil boiler, eliminating the need for frequent monitoring or chemical treatments to prevent corrosion. This greatly reduces maintenance efforts and costs, and operators do not need to have complex skills to perform daily operations.
Compared to steam heaters, thermal oil heaters can reduce energy consumption by up to 20%. This is mainly due to the fact that it avoids the heat losses associated with steam heaters during feedwater preheating, discharge and steam trapping. Efficient energy utilization not only reduces operating costs, but also meets the requirements of sustainable development.
Due to the higher thermal efficiency of the thermal oil heaters, their total exhaust emissions are reduced accordingly. This is positive for the environment and helps companies to meet increasingly stringent environmental regulations.
Because thermal oil has a higher boiling point than water, thermal oil heaters are able to operate in a higher temperature range (-40 to 750°F or -40 to 400°C) than steam heaters. In addition, thermal oil heaters can heat process fluids in different operating temperature ranges through secondary control loops, providing greater flexibility in temperature control.
Compared to steam boilers, thermal oil heaters operate at lower pressures, which eliminates the risk of possible pressure-related explosions to facility personnel. The lower pressure operating environment reduces the likelihood of equipment failure due to excessive pressure, improving workplace safety.
As an important piece of equipment in the field of industrial heating, thermal oil boilers offer a unique working principle, a variety of types, a wide range of applications, and significant advantages. Whether in the wood, textile or chemical industries, it plays an indispensable role. With the continuous development of industrial technology, the performance and efficiency of the thermal oil boiler also continues to improve.
For enterprises, an in-depth understanding of the thermal oil boiler will help them choose the right equipment according to their needs, improve productivity, reduce costs and achieve sustainable development. If you have any questions about the selection, use or maintenance of thermal oil boilers, we recommend consulting a professional for more detailed guidance and solutions.
