Syngas production from municipal solid waste with a reduced tar yield by three-stages of air inlet to a downdraft gasifier

Health risk assessment (HRA) methodologies of three stages of Municipal Solid Waste Landfill (MSWL), including operation period, maintenance and management period after closure, and usage period without any restricted limits were built in this paper. The major exposure pathways to environmental contaminants were considered: inhalation of gas and dust during operation period, and ingestion of four food pathways categories (plant foods, meat, milk, and fish), groundwater and dust during usage period without any limits. The endpoints of HRA of MSWL are individual lifetime carcinogenic risk for all the carcinogenic chemical contaminants, and hazard index (HI) for all the non-carcinogenic chemical contaminants to the landfill worker (only at the operation period), and to the public near to the landfill (at all the three stages) respectively. The parameter values of calculation model are conservatively chosen. This is the first time in China that an integrated risk assessment methodology for landfill gas and leachate is attempted to develop. HRA methodologies will facilitate rapid estimation of the risk level of MSWL.

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An Investigation Into the Syngas Production From Municipal Solid Waste (MSW) Gasification Under Various Pressures and CO2 Concentration Atmospheres

17th Annual North American Waste-to-Energy Conference ◽

10.1115/nawtec17-2351 ◽

2009 ◽

Cited By ~ 6

Author(s):

Eilhann Kwon ◽

Kelly J. Westby ◽

Marco J. Castaldi

Keyword(s):

Thermal Degradation ◽

Municipal Solid Waste ◽

Solid Waste ◽

Co2 Concentration ◽

Operating Regime ◽

Inert Atmosphere ◽

Syngas Production ◽

Gasification Process ◽

Degradation Step ◽

Char Burnout

The Municipal Solid Waste (MSW) gasification process is a promising candidate for both MSW disposal and syngas production. The MSW gasification process has been characterized thermo-gravimetrically under various experimental atmospheres in order to understand syngas production and char burnout. This preliminary data shows that with any concentration of carbon dioxide in the atmosphere the residual char is reduced about 20% of the original mass (in an inert atmosphere) to about 5%, corresponding to a significant amount of carbon monoxide production (0.7% of CO was produced from a 20mg sample with 100ml/min of purge gas at 825°C). Two main steps of thermal degradation have been observed. The first thermal degradation step occurs at temperatures between 280∼350°C and consists mainly of the decomposition of the biomass component into light C1–3-hydrocarbons. The second thermal degradation step occurs between 380∼450°C and is mainly attributed to polymer components, such as plastics and rubber, in MSW. The polymer component in MSW gave off significant amount of benzene derivatives such as styrene. In order to identify the optimal operating regime for MSW gasification, a series of tests covering a range of temperatures (280∼700°C), pressures (30∼45 Bar), and atmospheres (100% N2, 0∼20%CO2+Bal. N2 with/without steam) have been done and the results are presented here.

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