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Co-gasification of coal and biomass is an effective way to utilize coal of low rank to alleviate problems of energy shortage and environmental pollution. In order to investigate the product distribution resulting from the co-gasification of coal and biomass in a fluidized-bed reactor, experiments were conducted at varying biomass ratios, oxygen equivalent ratios, steam/carbon ratios, and also gasification temperatures. With an increase of biomass ratio, the amount of CO and CH4increased while H2and CO2contents decreased. The amount of H2increased obviously with an increase of gasification temperature ranging from 650 to 1000°C, whereas the CO and CO2amount decreased. An increase of the steam/carbon ratio was beneficial to promote H2formation and decrease CO and hydrocarbon compounds. With an increase of the gasification temperature, the steam/carbon ratio and oxygen equivalent ratio can promote the elements with low reaction activity in biomass gasification to be useful gas compositions. [ABSTRACT FROM PUBLISHER]

The release behavior of As, Hg, Pb, and Cd in Yima during coal gasification was investigated in a fixed-bed reactor. Their modes of occurrence in coal and residues after gasification were determined by XRD and sequential chemical extraction. Pb is mostly associated with mineral matter formations in parent coal. A large proportion of Cd and As is stably associated with organic matter and sulfides. Hg is mainly that of being bound to organic matter but could be easily changed during coal gasification. It is found that bleeding ratios of As, Hg, Pb, and Cd increased with an increase of the gasification temperature, especially for Pb and As under CO2 atmosphere at high temperature. Among the toxic trace elements studied herein, Hg and Cd were found to be more volatile and enriched in the gas phase while Pb and As were mainly relegated to the solid phase during coal gasification. [ABSTRACT FROM AUTHOR]