Index Control of Thermal Efficiency and Fuel Consumption for Steel Rolling Heating Furnace

Thermal efficiency and fuel consumption of heating furnace

The thermal efficiency and fuel consumption of a heating furnace are important indicators for evaluating the working condition of the furnace. Fuel consumption refers to the unit fuel consumption, also known as unit fuel consumption, coal consumption, and energy consumption, which refers to the amount of fuel consumed per unit mass (per ton or kilogram) of heating products. The unit fuel consumption depends on heating time, heating system, heating furnace structure, output, steel grade, furnace inlet temperature, etc. The higher the output of a continuous heating furnace, the lower the unit fuel consumption.

The thermal efficiency of a furnace refers to the percentage of the effective heat of heating metal in the heat supplied to the furnace (the burning heat of fuel). According to actual measurements, the thermal efficiency of a continuous heating furnace is about 30% -40%.

In actual production, what we pursue is high thermal efficiency and low fuel consumption. What are the specific measures? Here are a few summary points for your reference:

1. Reduce the heat carried away by exhaust gas from the furnace. Exhaust gas is the main component that carries away heat. On the premise of ensuring complete combustion, the excess air coefficient should be minimized as much as possible. To increase the combustion temperature and reduce the amount of exhaust gas, but if the air volume is insufficient or the combustion conditions are not good. It can also cause incomplete combustion. Not only can the fuel consumption not be reduced, but it will also lower the combustion temperature and worsen the heat exchange in the furnace. Pay attention to the sealing of the furnace and control the pressure at the bottom of the furnace at a slightly positive pressure. Prevent cold air from being sucked into the furnace and increase the amount of flue gas in the furnace. To control a reasonable exhaust gas temperature. The higher the temperature of the exhaust gas, the more heat it carries away, and the lower the thermal efficiency, but the exhaust gas temperature is too low. The average temperature inside the furnace decreases. Heating is too slow. The production efficiency of the furnace has decreased. The heat contained in the exhaust gas should be recycled to improve thermal efficiency and reduce fuel consumption.

2. Recycling waste heat for preheating air and gas. This way, the heat can be brought back to the furnace, which can directly improve the thermal efficiency of the furnace, reduce fuel consumption, and also use waste heat to produce steam for power generation or other purposes. The waste heat power generation project of the CSP heating furnace at Baosteel utilizes the waste gas from the heating furnace to generate electricity, which is then fed back to the enterprise. The project is currently in progress.

3. Reduce the heat carried away by the cooling water of the furnace. To reduce the heat carried away by the cooling water in the furnace, the cooling area can be optimized. Insulate and wrap the water-cooled pipes. Using vaporization cooling instead of water cooling;

4. Reduce the heat dissipation of furnace masonry. Using lightweight refractory materials and various insulation materials. It can effectively reduce the heat loss through masonry conduction.

5. Strengthen the thermal management of the furnace. The furnace should maintain balanced operation at rated output and adjust and optimize the heating system to ensure that the heating furnace is in a better state.