Synergistic effects of co-gasification of municipal solid waste and biomass in fixed-bed gasifier

Abstract

The co-gasification of refuse derived fuel (RDF) and biomass is a promising technology for environmentally friendly municipal solid waste (MSW) utilization. Herein, we investigated the co-gasification of RDF and straw mixtures. The development of syngas suggested that higher temperature and equivalence ratio (ER) values promote syngas yield during gasification and co-gasification. Temperature plays a positive key role in gas yield and carbon conversion efficiency once the ER is higher than 0.3 during co-gasification. Except for an ER of 0.3, synergistic enhancements in carbon conversion efficiency, gas yield, and cold gas efficiency were observed for co-gasification. The positive synergistic effects of co-gasification mainly appeared in lower ER (0.1−0.2) and higher temperatures (800−900°C); however, the negative synergistic effects more tend to appear in higher ER (0.3−0.4). From the development of bottom ash in co-gasification, at higher temperature and ER values, potassium in the bottom ash was favored to stay in sulfur-containing compounds; whereas at lower temperature and ER values, potassium preferred to exist in potassium chloride. A higher calcium content more easily enriched in small particles that were integrated into aluminosilicate led to the formation of sticking ash particles, which could promote significant melting agglomeration. However, these melting agglomerations could be suppressed by adding straw into the RDF. These results provide a feasible method for the resource utilization of MSW.