Low-temperature co-gasification of rice husks and waste tires as an alternative fuel in the cement industry: Investigation of synergistic mechanisms and their targeted optimization

To support low-carbon transformation in the cement industry, this study investigated the low-temperature co-gasification of rice husks (RH) and waste tires (WT) as an alternative fuel. Gasification experiments in a tubular furnace examined the effects of varying RH to WT mass ratios and excess air number (α), while molecular dynamics simulation explored the reaction mechanisms of their main components, cellulose (CE) and styrene-butadiene rubber (SBR). The results showed that co-gasification exhibits both inhibitory and synergistic effects: WT initially suppresses RH decomposition but later promotes the release of combustibles. Although gas yield decreased, the lower heating value (LHV) of gas improved significantly, with the highest synergistic effect (51.45 %) at α = 0.20 and a mass ratio of RH to WT of 3:7. Co-gasification also reduced Si and S in the solid product, thereby reducing the risk of clinker skinning. CE provided hydrogen and hydrocarbon radicals that contribute to the generation of combustible gases. SBR provided aromatics that helped reduce NO_x emissions. Precise modulation of syngas composition, calorific value, and carbon distribution in gasification products was achieved through regulation of the RH-to-WT ratio and controlled gasification temperatures. Thus enabling targeted implementation of low-temperature co-gasification as an alternative energy solution in cement manufacturing systems.