Enhanced looping biomass/vapour gasification utilizing waste heat from molten copper slags

The syngas generation from biomass/vapour pyrolysis wih molten copper slag is an innovative technology in chemical industry. Copper slag and rice straws are representative undervalued trashes as metallurgical and agricultural by-products. But the inappropriate handling of them, including direct burying or open burning, could severely aggregate environmental pollution. This present study investigated the biomass pyrolysis integrating waste heat from molten copper slags through carbon-loops extension. The mechanism of integrated looping gasification was identified, where the effects of the mass ratio of FeO/SiO2, minor elements contents of (Al2O3+CaO), operational temperature and pressure on target syngas yields were systematically explored through thermodynamic calculation and experimental results. Thermodynamics calculations confirmed that increased mass ratio of FeO/SiO2 (higher than 1.5) and minor elements contents showed obvious catalytic effect on syngas generations, promoted, accompanied with obvious reduction of air pollutants emission. Since FeO favoured solid biomass conversion into syngas, exergy efficiency of generated syngas increased as the mass ratio of FeO/SiO2 was enhanced. Non-isothermal experiments confirmed the incorporation of FS1-5 and FS5-1 obviously undermined the polluting gas yields, which were in overall agreement with thermodynamics results. Meanwhile, the solid ash waste could serve as raw materials for soil nutrients, and the generated syngas could be utilized for electricity generation, based on which an integrated and sustainable looping system would be proposed. Therefore, the favourable results could thus provide significant insights for deepened understanding of biomass gasification as well as the efficient utilization of rice straw and copper slag. •The carbon-loops circulating copper industry and biomass utilization was optimized.•The influence of copper slag composition on syngas yields was proposed.•Exergy efficiency of syngas increased as the mass ratio of FeO/SiO2 was enhanced.•Non-isothermal experiments confirmed copper slag undermined the polluting gas yields.