Parametric study of product yield and process efficiency of food waste plasma gasification using CFD

Plasma gasification is a promising alternative to achieve waste detoxification and valorization. This study establishes a CFD model based on the Euler-Lagrange method to simulate the plasma gasification process of food waste. This study focuses on the pyrolysis behavior of the feedstock in the plasma gasifier and the subsequent gasification process, systematically evaluating product distribution and process efficiency based on two critical parameters of equivalence ratio (ER) and plasma energy ratio (PER). The investigation on the primary pyrolysis yield of food waste reveals that a high PER favors non-condensable gas production accompanied by a reduction in tar formation, with carbon yield always being low. The complementary interaction between ER and PER is explored with respect to its impact on the gasification process and product characteristics, demonstrating the advantage of plasma gasification in reducing oxidant requirements, thereby producing tar-free syngas with a high lower heating value (LHV). The simulation results suggest that the optimal range of ER is 0.1–0.2, which is lower than that of conventional air gasification, with corresponding PER values of 0.25-0.15 through trade-offs among carbon conversion efficiency (CCE), cold gas efficiency (CGE), lower heating value (LHV), and processing capacity. Our findings deepen the understanding of plasma gasification.