Characteristic of Particulate Matter from Combustion of Zhunong Lignite: A Comparison between Air an Oxy-fuel Atmospheres

The transformation of soium to particulate matter (PM) uring lignite combustion has been wiely investigate, while the importance of Ca, Mg, S, an Fe in low-rank coal has been recently reveale. In this stuy, three kins of Zhunong lignites (ZD, YH, an HSY) rich in Na, Mg, Ca, S, an Fe were selecte an the combustion was conucte in an entraine flow reactor with a furnace temperature of 1473 K. PM was sample by a Deakti low-pressure impactor (DLPI), an the components were analyze by scanning electron microscopy equippe with energy-ispersive X-ray spectrometry (SEM-EDS), with the PM number concentration measure by a scanning mobility particle sizer (SMPS). The characteristics of PM uner air an oxy-fuel (Oxy21, Oxy30, an Oxy40) atmospheres were compare. The results show that the comparable O₂ concentration is relate to coal properties an locate between 30 an 40% for Zhunong lignite. It is acceptable to take the PM₁₀ mass yiel as a reference to reflect the combustion intensity. An oxy-fuel atmosphere has more effect on PM_1-10 than PM₁. The participation of Na in PM₁ is highest uner Oxy21 combustion, which is enhance through S an Cl. An increasing O₂ concentration will intensify the fragmentation an ecomposition of Ca-, Mg-, Fe-, an Si-bearing minerals, which contribute mostly to the prouction of PM_1-10. The contents of Si-Al-bearing minerals in raw coal significantly affect the contribution of Fe an S on PM_1-10 through eutectic formation. Besies, the vaporization of inorganic elements (mostly Ca, Mg, Fe, an Si) will also be enhance uner oxy-fuel combustion at a higher O₂ concentration, increasing the PM₁ prouction an moving the number-base particle size istribution (NPSD) towar a larger particle size.