Pulverized coal is transported pneumatically using an inert carrier gas into the gasifier, where it contacts oxygen and steam. To protect against the high gasification temperatures of up to 1600°C, a membrane wall that consists of high-pressure water/steam tubes is used. Multiple side burners and a proven swirl design allow efficient separation of the syngas from the slag. The slag flows down into a water bath, where it is extracted as a solid. The multiple burners provide the potential for easy scale-up.

The hot syngas that exits the gasifier is first quenched using ‘cold’ recycled syngas and then further cooled in an external convective cooler to generate high- and medium-pressure steam as valuable by-products. Alternatively, the hot syngas can also be cooled by direct contact with water in a bottom quench configuration.

Pulverized coal is mixed with water to form a slurry that is pumped into the gasifier via a single burner at the top of the reactor. Contact with oxygen starts the gasification reactions. In the slurry-feed process, the inside of the gasifier is lined with refractory bricks to protect against the high heat loads. The hot syngas and slag then pass through a quench water pool where molten solids are fused as slag and syngas is cooled while exiting the reactor.

In order to extract more useful heat from the hot syngas, a radiant syngas cooler can be applied directly at the exit of the gasifier such that the syngas is cooled and high-pressure steam is raised.