Factors affecting temperature rise?

It mainly involves the amounts of C and H, as well as the moisture content; the levels of these elements are related to the calorific value. Another factor is the amount of air introduced. These things can only be understood through practical experience on a daily basis. I’m really sorry – our oil furnaces are all shut down at the moment; if they weren’t, I could explain things more clearly

Properties of fuel 1. Properties of fuel oil: The key quality parameters for fuel oil include viscosity, flash point, moisture, mechanical impurities, freezing point, ash content, and sulfur content. Its meaning is: viscosity ； The viscosity of fuel oil is a measure of its flow resistance, and it indicates the ease or difficulty of transporting and atomizing the fuel oil. The viscosity level determines the design of the nozzle and the quality of atomized combustion. Flash point: The lowest temperature at which a mixture of fuel oil vapor and air, under atmospheric pressure and under standard conditions, will ignite spontaneously when exposed to a flame. It indicates the ease of ignition of fuel oil. It is to ensure safety and prevent injuries from fuel flashback before proper combustion takes place in the furnace. Ignition point: At atmospheric pressure, when the fuel oil is heated to specified standard conditions, its vapor-air mixture catches fire upon contact with a flame, and the combustion lasts for at least 5 seconds; the lowest temperature at which this occurs is known as the ignition point. The ignition point is generally slightly higher than the flash point. Natural point: The temperature at which fuel oil slowly oxidizes and begins to burn on its own. In particular, the autoignition temperature of heavy fuel oil is much lower than that of light fuel oil; for example, the autoignition temperature of gasoline is 510–530°C, while that of vacuum residue is 230–240°C. The air in tubular heating furnaces is generally preheated to 200–250°C; if oil leaks from the nozzles into the air ducts, it can easily cause a fire. Freezing point: The temperature at which fuel oil loses its flowability. Depending on the freezing point, appropriate insulation and heat tracing measures should be taken when transporting fuel oil to prevent the oil in the pipelines from freezing. Pour point: The temperature at which fuel oil just begins to flow under standard conditions. Generally, the pour point is the freezing point plus 2.5°C. Elemental composition: Fuel oil is primarily composed of carbon and hydrogen, with elements such as sulfur, oxygen, and nitrogen as well. Ash: Ash refers to the non-combustible substances that remain after burning under specified conditions. The composition of ash is generally considered to be various metal elements and their salts. The ash content in fuel oil is generally less than 0.2%. These include sodium, magnesium, vanadium, nickel, iron, silicon, and other metal compounds. Ash can cause salt deposition outside the furnace tubes in the radiation chamber, ash accumulation on the coils in the convection chamber, blockages due to ash sticking in the low-temperature sections, high-temperature corrosion of the furnace components, and erosion of the refractory materials. Thermal properties of fuel: Since heating furnaces are designed to utilize the heat generated by fuel combustion, it is necessary to understand the main thermal properties of the fuel. Fuel calorific value: It is the heat released when 1 kg of fuel burns completely. Low calorific value: It is the heat released when 1 kg of fuel burns completely, minus the heat required to evaporate the water contained in the fuel as well as the water produced during combustion into water vapor; the remaining heat is referred to as the low calorific value of the fuel. It is also known as the effective calorific value. A lower calorific value is used in actual calculations. High calorific value: It is the heat released when 1 Kg of fuel is completely burned, with the water contained in the fuel combustion products in liquid form. It is also known as the theoretical calorific value. The high calorific value is only of comparative significance; the difference between it and the low calorific value equals the heat released when the total amount of water vapor condenses into liquid water. Because the temperature of the flue gases generated during combustion is very high and their pressure is very low, the water contained in the fuel as well as the water produced by combustion can only exist in the form of water vapor under such conditions; it is impossible for them to condense into liquid water. Therefore, a lower calorific value is used in the calculations. The lower the calorific value of the fuel, the better its quality, and less fuel is required.

It depends on the calorific value and heat release rate of the fuel. Heat transfer area and heat transfer rate.

What is the impact of the composition of the fuel required for the fuel furnace heating system on the heating rate? Does the composition of the fuel required by the fuel furnace heating system affect its enthalpy value? The fuel required for fuel furnace heating systems varies in composition, resulting in different calorific values; it also affects the demand for steam and air, as well as the rate of temperature increase. The composition of the fuel required for the fuel furnace heating system varies, and thus its enthalpy value also changes; here, the calorific value should be taken into consideration.