Feasibility of Biomass Low-temperature Gasification Products as Alternative Fuels for Cement: A Contrastive Research of Autothermal and Allothermal Fluidized-Bed Systems

• Comparative low-temperature gasification in autothermal and allothermal modes. • Studied effects of temperature, ER, size, and moisture on low-temperature gasification. • Autothermal runs produced more reducing gas than isothermal units. • Autothermal gasifier performance aligns with process-scale operation. • Gasification products heat cement pre-calciners, replacing fossil fuels. Hot products from low-temperature biomass gasification can directly displace traditional fossil fuels in cement production, while alleviating agglomeration risks relative to high-temperature operation. Nevertheless, most laboratory investigations rely on externally heated (allothermal) reactors, where decouple bed temperature from reaction exothermicity and may yield characteristics deviating from industrial behavior. Here, autothermal and allothermal fluidized-bed gasification of corn stover were systematically compared under matched low-temperature conditions. Benchmarking against an industrial-scale gasifier (dry gas yield, Y g , 0.97 Nm 3 /kg; lower heating value, LHV, 10.71 MJ/Nm 3 ), the autothermal operation at ER 0.20 successfully reproduced similar performance (Y g 0.97 Nm 3 /kg; LHV 9.53 MJ/Nm 3 ). In contrast, the allothermal counterpart significantly underestimated the gasification potential (Y g 0.51 Nm 3 /kg; LHV 5.25 MJ/Nm 3 ), with the discrepancy becoming most pronounced under moisture-containing conditions. Building on this contrast, the effects of temperature, equivalence ratio (ER), biomass particle size, and moisture on autothermal gasification characteristics were further quantified. The results confirm an optimal autothermal regime (710°C, ER 0.15, 0.15–0.25 mm particles, 11.5 wt.% moisture), delivering a stable high-quality gas suitable for direct injection into cement pre-calciners. Overall, this work not only enables resource utilization of solid wastes but also advances the deployment of alternative fuels in the cement industry.