Incidents of explosions in ash treatment facilities at waste incineration plants have been reported. The cause is believed to be the reaction between cooling water and metallic aluminum contained in the ash, which generates hydrogen gas.

The authors have been investigating methods to suppress hydrogen generation through temperature changes during the conveyor transport process of ash treatment equipment. In this study, to replicate the temperature changes during conveyor transport, an experiment was conducted in which heated simulated incineration ash was immersed in water within a container for cooling. After cooling, the simulated ash was removed from the water, and the hydrogen gas concentration around the simulated ash was measured. The simulated incineration ash was composed of a mixture of aluminum powder, alumina powder, calcium oxide powder, and silicon dioxide powder, which are the main components of incineration ash.

The experimental results showed that as the temperature of the water during immersion increased, the amount of hydrogen gas generated during immersion decreased, and the hydrogen gas concentration around the simulated ash also decreased.

Based on these results, it was found that by maintaining the high-temperature incineration ash discharged from the furnace and the cooling water above 70°C and allowing natural cooling during transport on the conveyor, it may be possible to suppress hydrogen explosions in the conveyor and ash pit.