Abstract: Biomass gasification, particularly when integrated with calcium looping sorption-enhanced hydrogen production technology, offers a promising pathway to convert biomass into high-value syngas while significantly enhancing hydrogen yield and enabling in-situ CO₂ capture to deliver substantial environmental and economic benefits. This paper presents an experimental investigation into hydrogen production and CO₂ capture via calcium looping sorption-enhanced biomass gasification conducted in a novel 1 MW_th compact-fast dual fluidized-bed pilot system. The reactor configuration comprises a lower bubbling fluidized bed (BFB) gasifier coupled with an upper riser reactor utilizing dolomite as a calcium-based CO₂ sorbent. The stacked design enables the effective integration of two distinct fluidization regimes—bubbling and fast fluidization—under individually adjustable temperature zones to offer remarkable operational flexibility and strong potential for industrial scalability. The ability of the system to decouple the gasification and regeneration processes, while maintaining continuous solids circulation, represents a significant advancement in reactor design for sorption-enhanced gasification. The experimental campaign focused particularly on the impact of two critical operational parameters, riser temperature and solid circulation flux, on key performance indicators, including product gas composition, hydrogen yield, cold gas efficiency, carbon conversion efficiency, and CO₂ capture rate. Under thermal operation, the system demonstrated notable stability, with the pressure differential established by the static bed height in the BFB serving as the primary driving mechanism for solid circulation between the two reactors. This auto-generated pressure balance effectively sustained the solid transfer without requiring additional mechanical assistance. The results indicated that the riser temperature had a profound influence on hydrogen production. Operating at an elevated temperature of 850 °C resulted in a peak hydrogen yield of 0.38 m³·kg^–1, with a hydrogen volume fraction of 59.14% in the product gas. Under these conditions, the cold gas efficiency, carbon conversion efficiency, and CO₂ capture efficiency reached 50.2%, 60.8%, and 78.8%, respectively. These findings demonstrate that higher riser temperatures significantly promoted endothermic reforming reactions, notably methane reforming and tar cracking, while simultaneously enhancing the in-situ CO₂ adsorption capacity of dolomite. The elevated temperature also improved the kinetics of heterogeneous reactions, contributing to increased gas quality and overall process efficiency. Increasing the solid circulation flux positively affected both the hydrogen concentration and total yield, as well as the CO₂ capture performance. Higher circulation rates facilitated greater transport of active CaO-based sorbents between the gasifier and regenerator, thereby increasing the availability of adsorption sites and improving the efficiency of the calcium looping cycle. However, it was also observed that reactor geometry constraints, operating conditions, and sorbent characteristics collectively have a significant influence on the overall capture efficiency and active space-time utilization. In particular, the interaction between the solid circulation rate, reaction temperature, and sorbent activity determined the ability of the system to maintain high-purity hydrogen production over extended durations. This study provides comprehensive experimental insights and a solid theoretical foundation for the scale-up and industrial implementation of calcium-based sorption-enhanced gasification coupled with efficient tar cracking. The findings confirm the viability of the proposed stacked dual fluidized-bed system as an efficient route for high-purity hydrogen generation from biomass with inherent carbon capture to support the transition toward advanced bioenergy systems with negative emissions potential.