CHAMPIONS OF EFFICIENCY
Energy saving according to ESA
Regenerative burners use the heat of the flue gases to preheat the combustion air. To this end, a pair of burners is used, each equipped with a “regenerative bed”, that is a tank full of alumina balls, while the heat exchange takes place in a two-phase cycle. When the first burner turns on, the second works as a chimney, i.e. it heats the ceramic spheres with the flue gases in the furnace.
After, the first burner turns off, the second one turns on and uses the combustion air which is pre-heated passing through the hot regenerative bed, and so on.
By heating the combustion air to the highest temperatures, maximum levels of efficiency are achieved.
If instead of a pair, a single burner is used with two separate regenerative beds, we are talking about self-regenerative burners.
Long flame regenerative burners
Long flame burners with refractory combustion head. Working with various gaseous fuels (NG, LPG, H2 & Blends, COG/BFG) or liquid fuels (diesel and bio fuels), up to 5 MW or more.
Flat flame regenerative burners
Flat flame burners with refractory combustion head, Possible use of multiple gaseous fuels (NG, LPG, H2 & Blends).
Customized regenerative burners
The burners can be customized, for example with regenerative beds upside down like in the picture.
Self-regenerating burners
The last development by ESA regenerative technology: Integrated double regenerators with SIC balls and single burner for applications with reduced heat capacity, such as small forges and heat treatments, working mostly in flameless mode.
Regenerative beds
Particular of ESA regenerators beds, which can be rotated every 30°from left position to right position. The regenerator can be provided with different air inlets, according to the furnace design.
Regenerator can also be supplied as spare for those customers who changes.
WHEN IS IT POSSIBLE TO USE THESE TECHNOLOGIES?
For each application the correct regenerative burner.
Regenerative burners “REGE NxT” are designed for intense heat requirements, using versions with long or flat flames and in various power capacities. They are used in ferrous metallurgy, in reheating and forging furnaces, or in aluminum melting furnaces. Preheated air can reach up to 1100°C.
FAQ ABOUT REGENERATIVE BURNERS
The efficiency of a furnace depends on multiple factors and the type of application. However, in ESA experience we can state that compared to cold air burners, regenerative burners allow fuel savings of over 50%. Various strategies are currently being studied to achieve even greater levels of efficiency.
The NOx problem is directly related to the increase in efficiency. The use of diluted combustion techniques (flameless and staged) makes it possible to reach very low “relative” emissions thresholds. If it is true that relative NOx can be high, it is equally true that thanks to the huge fuel savings, in reality the quantity of absolute NOx emitted are reduced, a fundamental aspect often ignored by regulations, not to mention the reduction of CO2 and other resources.
Yes, although the higher flame temperature and its tendency to stitch to the nozzle cause significant increases in NOx emissions. Nonetheless, the considerations already set out above apply here, with the added advantage of further reductions/cancellations of CO2 emissions.
Unfortunately, generalizations cannot be made. Too many input/outputs (i.e the fuel directly used, the quality and the quantity of the metal obtained, times, oxygen availability…) should be considered, so that in practice, oxy fuel technology is chosen mostly depending on the presence of very contaminated wastes, which the oxygen can much more easily burn.
Despite a slightly superior heat exchange power, ceramic honeycombs are too fragile, too expensive and subject to quickly clog for an industrial use. Alumina balls on the opposite can be used several times by simply washing them, are cheap, and if they break down, they get even higher heat exchange efficiency!
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