Evolution of Particulate Matter in a Municipal Solid Waste Incinerator: Probing into the Effects of a Rotary Spray Semi-dry Scrubber and a Baghouse

Systemic field measurements of PM10 were carried out on a grate-type municipal solid waste (MSW) incinerator to investigate the formation characteristics of PM10 and the effects of a semi-dry flue gas deacidification scrubber (lime slurry spraying and activated carbon powder injection) and a baghouse on its emission. The particle size distribution (PSD), mass concentration, chemical composition, and micromorphology of PM10 in the flue gas at the scrubber inlet, the scrubber outlet, and the baghouse outlet were comprehensively determined. The results showed that the PSD of PM10 formed from MSW incineration was tri-modal. The peak of PM in the central mode (0.3-3 mu m) was dramatically higher than that of either the ultrafine mode or the coarse mode, most possibly due to the high contents of volatile mineral matter (e.g., Na and Cl) and nanomaterial-/micro-material-containing wastes in the MSW fuels. The mass yields of PM1, PM2.5, and PM10 decreased by 28.24, 59.26, and 53.91%, respectively, after passing through the semi-dry scrubber; however, some new particles formed from the slurry droplet. The baghouse could effectively remove the PM with the removal efficiencies for PM1, PM2.5, and PM10 being over 99.95%. Comparatively speaking, more PM2.5 was generated in the combustion of MSWs than agroforestry or coal in the furnace.

Automated summary

Systematic field measurements on a grate-type municipal solid waste incinerator were conducted to investigate PM10 formation characteristics and the effects of a semi-dry flue gas deacidification scrubber and a baghouse on its emission. It was found that the semi-dry scrubber reduced PM yield significantly, but new particles were formed from the slurry droplets. The baghouse showed high removal efficiencies for PM1, PM2.5, and PM10, indicating its effectiveness in removing particulate matter. Additionally, more PM2.5 was generated from the combustion of municipal solid wastes compared to agroforestry or coal.