Year: 2025
Type: article
Abstract: In the work a method for achieving a specific NOx emission indicator in accordance with the EU IED directive for existing high-capacity boilers at combustion gas was proposed. The method is based on the maximum possible percentage of the injection of flue gases recirculation into the blowing air of the burners and reducing the steam generation (or heat output) of the boiler (reducing specific volumetric thermal load of the firebox) with using the existing flue gas exhauster and blower fan (the flue gases is supplying to the suction of the blowing fan). The calculation of a typical steam boiler BKZ-75-39GMA at combustion of natural gas showed that when flue gases recirculation is introduced into the blowing air of the burners the adiabatic temperature, that depends on the percentage of flue gases recirculation, decreases by 261 К at 30 % of flue gases recirculation (at λf = 1.1). At the same time, when the boiler capacity is reduced from D = 75 t/h to D = 63.75 t/h of steam production (at 30 % of flue gases recirculation), the air heating temperature increases only by Δtair = 14 °С, while at the nominal capacity the increase by Δtair= 43 °С, which, if implemented, would negatively affect the resource of burners, air heaters and NOx formation. However, the gross efficiency of the boiler decreases from h = 93.7 % to h = 92.7 %, that is by 1 % and weakly depends on the boiler capacity in the range of 85–100 % at 30 % of flue gases recirculation. Bibl. 18, Fig. 7, Tab. 1.
Language: English
Subfield: Energy Engineering and Power Technology
Field: Energy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7117240751