FLOX is a flameless
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combus ...
process developed by ''WS Wärmeprozesstechnik GmbH''.
History
In experiments with industrial gasoline engines conducted in April 1990, Joachim Alfred Wünning found that when combustion occurred at a temperature greater than 850 °C, the flames were blown away. Although this observation was initially thought to be an error, it turned out to be a discovery which led to the invention of what he called FLOX-Technology, a name derived from the German expression "flammenlose Oxidation" (flameless oxidation). The advantages of this technology attracted funding for a project at Stuttgart University called FloxCoal, a programme aiming to engineer a flameless atomizing coal burner. The reduced
pollutant
A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like o ...
emission in FLOX combustion has been considered a promising candidate for use in
coal pollution mitigation
Coal pollution mitigation, sometimes called clean coal, is a series of systems and technologies that seek to mitigate the health and environmental impact of coal; in particular air pollution from coal-fired power stations, and from coal burnt b ...
and the higher efficiency combustion in FLOX received increased interest as a result of the
1990 oil price shock. FLOX burners have since been used within furnaces in the steel and metallurgical industries.
Technology
FLOX requires the air and fuel components to be mixed in an environment in which exhaust gases are recirculated back into the combustion chamber. Flameless combustion also does not display the same high energy peaks as the traditional combustion observed within a swirl burner, resulting in a more smooth and stable combustion process.
When combustion occurs,
NOx is formed at the front of the flame: suppression of peak flame offers the theoretical possibility of reducing NO
x production to zero. Experiments with FLOX-Technology have established that it can reduce the amount of NO
x generated by 20% in the case of
Rhenisch brown coal
Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...
, and by 65% in the case of Polish black coal.
The role of combustion temperature in NO
x formation has been understood for some time. Reduction of the combustion temperature in gasoline engines, by reducing the compression ratio, was among the first steps taken to comply with the
U.S. clean air act in the 1970s. This lowered the
NOx emissions by lowering the temperature at the flame front.
References
External links
* {{cite journal, url=http://www.heise.de/tr/artikel/Brenner-ohne-Flamme-1375157.html, title=Brenner ohne Flamme, author=Tanja Ellinghaus, journal=Technology Review, date=2011-11-11, language=German
list of article at WS Wärmetechnik
Combustion