BASICS
The most important issues in the steel industry have always been energy consumption and air pollution. Especially after April 2002, when the Kyoto Protocol on climate change entered into force. Since then, performance targets for fossil fuel-fired furnaces have become much more stringent as mandated by international authorities. By 2020, kiln technology has moved towards other goals such as reducing NOx emissions (by ~90%) and reducing fuel consumption (20-30%), fuel replacement capability, plant downsizing, improving product quality and cost reduction.
Therefore, the main objectives in the design of combustion systems for the steelmaking industry are the simultaneous increase in energy efficiency and reduction of pollutant emissions. The most commonly used technique to improve furnace efficiency is extensive air preheating, as it significantly reduces fuel consumption. However, the well-known disadvantage is that NOx emissions increase in parallel.
From this perspective, the steel industry has distinctive benefits due to the development of fundamental knowledge of flameless technology, showing significantly lower NOx emissions and thermal uniformity.
At present it is clear that primary methods for CO2 reduction for rolling mill billet annealing furnaces must be considered strictly in relation to specific consumption or combustion efficiency. Accordingly, the use of flameless regenerative burners has proven to be the right approach to target energy savings along with NOx emission reduction in these furnace applications. However, due to the lack of industrial application of large-size, very low NOx regenerative systems in Europe, one must know how they need to be improved in operation before being applied to existing steel annealing furnaces.
It is not possible to operate the flameless burner in flameless mode in a cold combustion chamber. Therefore, the combustion chamber must be heated with a constant flame, which can be switched to flameless mode as soon as the furnace exceeds the autoignition temperature of the fuel. This is a standard procedure when using Flameless burners. As soon as the temperature in the furnace exceeds 750 degrees, the burners cut the flame and start to spray air and gas inside and use the combustion chamber as the furnace interior. In this way, since a homogenized temperature is provided at every point of the furnace, annealing is done equally on all sides of the annealed billet. In this way, the scale rate is significantly reduced.
TECHNICIAL SPECIFICATIONS
Wide capacity range,
Low NOx value,
Decrease in scale rate,
AREAS OF USAGE
Billet annealing furnaces, heat treatment furnaces, steel annealing furnaces for the iron and steel industry.
