On the basis of low NOxburner retrofit in a 420t/h boiler

the combustion mechanism and NOxemission characteristics of Zhehun blended coal was studied.The TG-FTIR analysis system was used to investigate the combustion and NOxemission characteristics of Zhehun blended coal

and a drop-tube furnace was applied to study the NOxemission characteristics at different temperatures and with different excess air coefficients.The results show that

the gas emissions during thermogravimetric analysis under different heating rates are basically the same.Increasing the heating rate is conducive to enhancing the reactivity of coal samples and improving the combustion characteristics.On the other hand

it will also make the combustion lag and NO2release earlier.The NOx emissions increase significantly with the excessive air coefficientα

especially whenαranges from 0.8to 1.2.With an increase in combustion temperature

the NOxemission increases

either in an oxidizing atmosphere or a reducing one

and there exists a greater increase in an oxidizing atmosphere.