In entrained flow gasification, the gasifying agent is mixed with the fuel to the process while actually entering the gasifier. This is different from many types of gasification being that the gasifying agent is essentially premixed with the feed before the actual gasification process. There are two main types of entrained gasifiers: slagging and non-slagging. In non-slagging gasifiers, the ash that is produced from the reactions flow through the reactor with the gas being produced; this may allow ash to leave the gasifier so it will need to be separated downstream in the process. In slagging gasifiers, the ash slides down the walls of the gasifier while the reaction takes place. This is the preferred method for biomass conversion, however ash content and volatile matter percentages should be considered.