Hydrogen rich syngas production from food waste via an integrated two-stage process of in-situ steam gasification after fast pyrolysis

This study introduced an integrated two-stage process (ITP) for treating the mixed food waste (MFW) and producing syngas with higher hydrogen fraction where in-situ steam gasification was conducted after fast pyrolysis at the same temperature. Characteristics of syngas (syngas yield, composition, H-2 yield, and high heating value (HHV)) from the proposed approach was first compared with that from conventional overlapping process (COP) of steam gasification process at the same temperature of 700 degrees C and then with that from ITP at a higher temperature of 850 degrees C. Syngas yield from ITP at 700 degrees C (0.91 m(3)/kg) was almost the same as the syngas yield from COP at 700 degrees C (0.85 m(3)/kg); however, the hydrogen and CO fraction were much higher (H-2: gasification part similar to 63%, average similar to 57.8%; CO: gasification part similar to 25%, average similar to 24%) than that from COP at 700 degrees C (H-2: 52%, CO: 19%). The hydrogen fraction in syngas further increased to 68% (from the gasification part) on increasing the ITP temperature to 850. Moreover, the syngas yield increased significantly (1.51 m(3)/kg) at the higher temperature of 850 degrees. Finally, change in HHV values and corresponding changes in cold gas efficiency (CGE) were also presented to evaluate the process performance.

Automated summary

This study introduced an integrated two-stage process for treating mixed food waste and producing syngas with higher hydrogen fraction. The proposed approach had higher hydrogen and CO fraction compared to the conventional overlapping process at the same temperature, and the hydrogen fraction and syngas yield further increased at a higher temperature.