Experimental investigation of N₂O formation in selective non-catalytic NO_x reduction processes performed in stoker boiler

Abstract

Stoker fi red boiler plants are common throughout Eastern Europe. Increasingly strict emission standards will require application of secondary NO x abatement systems on such boilers. Yet operation of such systems, in addition to reducing NO x emissions, may also lead to emission of undesirable substances, for example N 2 O. This paper presents results of experimental tests concerning N 2 O formation in the selective non-catalytic NO x emission reduction process (SNCR) in a stoker boiler (WR 25 type). Obtained results lead to an unambiguous conclusion that there is a dependency between the NO x and N 2 O concentrations in the exhaust gas when SNCR process is carried out in a coal-fi red stoker boiler. Fulfi lling new emission standards in the analysed equipment will require 40-50% reduction of NO x concentration. It should be expected that in such a case the N 2 O emission will be approximately 55-60 mg/m³, with the NO x to N 2 O conversion factor of about 40%.

Archives of Environmental Protection

“…The maximum emission of nitric oxides was estimated in accordance to the methodology proposed in (Collection of methods for calculating emissions of pollutants into the atmosphere by various industries 1986). The amount of NO x emitted to the atmosphere (g/s) converted to NO 2 , can be counted by using dependence (1) (Krawczyk 2016, Szkarowski et al 2016, Kuropka 2010, Kormilitsyn and Ezhov 2013, Lee et al 2006. -for DKVR 20-13 boiler P g/s.…”

Full-Scale Investigation of Dry Sorbent Injection for NOx Emission Control and Mercury Retention

“…Even relatively mature technologies such as typical Selective Non-Catalytic Reduction (SNCR), when applied in small furnaces of stoker boilers, may not guarantee desired results. There is very limited research concerning the application of secondary denitrification systems in stoker boilers and usually typical SNCR is investigated [4][5][6]. Numerous studies propose primary methods such as air staging, staged combustion or flue gas recirculation technology (FGRT) as a method for NO x limitation in stokers and grate boilers [7][8][9].…”

Combined NOx and NH3 Slip Reduction in a Stoker Boiler Equipped with the Hybrid SNCR + SCR System FJBS+

“…Based on the authors' experience and previous research, NO x concentration strongly depends on the stoker operating conditions: the operation of primary air zones, speed of grate movement and thickness of the fuel layer on the grate. There is very limited research concerning the application of denitrification systems in stoker boilers and usually SNCR is the only one investigated [15][16][17][18]. For most European technologies effectiveness of NO x reduction is in the range of 50-65%.…”