Yazhuo Wang

Chlorine migration mechanisms during torrefaction of fermentation residue from food waste

Fermentation residue from food waster (FRFW) has a large amount of residual chlorine (Cl), and the high-salt of FRFW is either landfilled or treated as a fertilizer. The transfer of chlorine to the atmosphere and soil can cause pollution and soil salinization. This work primarily investigated the combined forms and migration mechanisms of Cl during the torrefaction of FRFW from 250 to 400 °C. The results showed that the form and amount of Cl released during the torrefaction of FRFW depended on temperature. The absolute content of soluble Cl and total Cl in torrefied solid products decreased, and the absolute content of insoluble Cl reached a maximum at 350 °C, which indicated that some soluble Cl was transferred to the insoluble Cl (CCl forms). The Cl-containing products in non-condensable gas was too little to be detected, so the majority of the reduced Cl was in liquids with different organic compounds.

Influence of Oxygen Concentration and Equivalence Ratio on MSW Oxygen-Enriched Gasification Syngas Compositions

Oxygen-enriched gasification for the treatment of municipal solid waste (MSW) is proposed in this chapter; mechanism analysis and thermodynamic calculations results show the advantages of lower heat loss than air gasification. The effects of oxygen concentration and equivalence ratio (ER) on gas products compositions were investigated. It was found that, during the ER range of 0.23–0.29, CO, H2, and CO2 content in combustible gas continuously increased, and CH4 content continuously decreased with the oxygen concentration in the gasification agent rising from 20 % to 100 %. Furthermore, when the oxygen concentration was 20 % or 40 %, the CO2 content in combustible gas grew constantly, and the CH4 content gradually decreased within the ER span of 0.23–0.29, however, CO and H2 contents increased then decreased when ER exceeded 0.27. In addition, when the oxygen concentration was 80 % or 100 %, the CO2 content grew, CO and CH4 content decreased gradually, and H2 content decreased when ER exceeded 0.25 and 0.27, respectively. Therefore, gas product quality could be improved through increasing oxygen concentration within a certain ER range.