Fuel combustion optimizing by regulated level of chemical underburn


1 Koszalin University of Technology, Koszalin, Poland

2 Koszalin University of Technology, 75-507 Koszalin ul. Rejtana 5A/5, Poland.


Variety of energy–ecology optimizing means that optimum result of fuel combustion is focused not only on the direct efficiency of its usage but also on minimum environmental damage. Best possible fuel combustion connected with controlled level of chemical underburn is considered to be one of the simpliest, cheapest and the most effective methods of optimizing. It is essential to notice that the meaning of common statement that minimum underburn responds to maximum efficiency of fuel combustion in boilers is undoubtedly incorrect. Radiation as well as convection heat reclaiming by screen surfaces surrounding boiler’s firing depend on ( in a very complicated way) various features: form, size, flames shining, location of maximum temperatures area and also on the shape of firing space aerodynamics.2 Standardized balance boiler’s tests show that maximum efficiency can be mentioned with highly noticeable
chemical underburn responding to concentration 0,02 – 0,03 % level of volume (200–300ppm). What is more, nitrogen oxide, which originates in maximum temperature (with lack of underburn), is 35 times more toxic than carbon monoxide. It can be supposed that defining the permissible level of chemical underburn is a typical optimizing issue due to minimize the destination function. The issue should be resolved individually in every specific area of boiler’s adjustment, with accounting such features as precise characteristics and details of firing – boiling set. That is why the optimizing issue is recognized to be really complicated and complex. To simplify and unify the issue, ecological and economical fuel combustion
criteria were proposed as well as general energy–ecology criterion, which is simultaneously the searched destination function. Results of such research on boilers have shown that optimum combustion operation
takes place within carbon monoxide concentration of 200–400 ppm. Automatic regulation of chemical combustion on such level results in a constant utilizin.