Sustainable Syngas Production From CO ₂ ‐Assisted Gasification of Solid Wastes: A Simulation‐Based Approach to CO ₂ Utilization

ABSTRACT

CO ₂ ‐assisted gasification offers a potential route for waste valorization and CO ₂ utilization, yet the suitability of chemically distinct wastes under comparable operating conditions remains insufficiently established. This study compares wood residue (WR), rice straw (RS), poultry litter (PL), and high‐density polyethylene (HDPE) using an Aspen Plus equilibrium model. The effects of temperature (500°C–1000°C) and gasifying agent‐to‐waste (G/W) mass ratio (0.5–3.0) on syngas composition, H ₂ /CO ratio, gas yield, lower heating value, cold gas efficiency, and net heat duty were evaluated. The feedstocks exhibited distinct thermodynamic responses. Biomass‐derived feedstocks generally showed improved gas‐phase performance with increasing temperature, whereas HDPE exhibited substantially higher gas yields and a distinct response to CO ₂ availability. Contour‐based trade‐off analysis and constraint‐based screening were further applied to identify feedstock‐specific feasible operating regions. Within the predefined operating window of 700°C–900°C and G/W = 0.5–2.5, using H ₂ /CO = 1–2 and CGE ≤ 100% as screening criteria, HDPE exhibited a broad feasible region, WR showed a highly restricted region, and no feasible regions were identified for PL and RS. These findings provide a systematic framework for preliminary feedstock and operating‐domain screening for CO ₂ ‐assisted waste‐to‐syngas conversion.