Gasification of municipal solid waste in a pilot plant and its impact on environment

Municipal solid waste from three cities was gasified in a 3 ton/day capacity gasification/melting pilot plant based on Thermoselect at a temperature of around 1,200 °C using double inverse diffusion flame burner. The synthesis gas (syngas) obtained from gasification contains 25-34% CO and 28-38% of H₂. The high heating value of syngas was in the range of 10.88-14.65 MJ/Nm³. Volatile organic compounds like furan, dioxin, and other organics in gaseous and liquid phase were effectively destroyed because of the high temperature of the high temperature reactor and shock cooling of syngas. Pollutants in exhaust gases were also found to be satisfying the Korean emission standard. Leaching concentration of heavy metals in the melted slag (vitrified mineral aggregate), fly ash, and treated water was much less than the Korean regulatory limit values due to high melting temperature (1,600 °C). The vitrified slag was of dark brown color. The glassy and amorphous nature of the vitrified mineral aggregate was further confirmed from SEM micrograph and XRD spectra of slag. The vitrified mineral aggregate could be used as natural raw material in cement and construction industry.