The application of fly ash gasification for purifying the raw syngas in an industrial-scale entrained flow gasifier

A fly ash entrained flow gasification process was developed to simultaneously remove and utilize fly ash in the raw syngas coming directly from fluidized and fixed bed gasifiers. The present in situ experiments at a full load of 80,000 Nm³/h showed that, compared to the raw syngas, the effective syngas (CO + H₂) concentration in the purified syngas was slightly decreased, from 72.98% to 72.63%. In contrast, the average mass fraction of carbon in the fly ash was greatly reduced, from 29.5% to below 2%. This gasification process was determined to rapidly heat the entirety of the raw syngas to more than 1285 °C based on fast combustion of a small quantity of the raw syngas and all of the gasifying agent. Thermal analysis showed that the initial gasification temperature of the raw syngas was 1985 °C. Heat loss from the purified syngas was 20.6% of the fuel heat quantity, while the heat loss from unburned combustible gas accounted for 75.1%. Laboratory-scale airflow experiments were also conducted to determine the volume concentration distribution of the gasifying agent at the outlet of a single burner.