Investigation of spraying lances used in low power boilers for non-catalytic reduction of nitrogen oxides (SNCR)

Roman KRZYWDA*, Bogumiła WRZESIŃSKA, Tomasz WĄSOWSKI – Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland
Please cite as: CHEMIK 2016, 70, 10, 605–610

Starting from 1990 norms concerning emission from power plants become more and more restrictive. In case of coal burning the limitation concerns among others nitrogen oxides (both NO and NO2 in equivalent of NO2).

Present standards are defined by Regulation of the Minister of the Environment from 2014 [1]. For the power below 50 MW coming from heat sources the nitrogen oxides limit, after 2015, in equal to 400 mg/m3 c, for range 50–100 MW – 300 mg/m3 c and for the power above 100 MW – 200 mg/m3 c. The power coming from heat sources is counted for all the boilers together if the exhaust gases are introduced to one emitter – chimney.

European Union is planning further restrictions concerning nitrogen oxides emission – new preliminary norms have been presented in Best Available Techniques (BAT) Reference Document for the Large Combustion Plants in 2013 [2]. For presently working 50–100 MW plants the proposed limit is equal to 270 mg/m3 c and for 100–300 MW the limit is 180 mg/m3 c. For new 50–300 MW plants the proposed limit is equal to 100 mg/m3 c.

It is seen that especially the small installations consisting of few boilers (i.e. WR 25 boilers – 29 MW, or commonly used WR 10 boilers) will have to obey the most restrictive norms. It is evaluated that several hundred of such boilers work in Polish industry.

The traditional methods (mainly burning technologies) for nitrogen oxides reduction can be applied for emission below 300 mg/m3 c that is why now it is a need for implementation of socalled secondary methods.

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