This type of gasifier system is more up to date than the previous technologies; this process focuses its optimization around attaining uniform temperatures and continuous contact between the solids and gases in the reactor. The solid material is usually sand or some type of catalyst; these particles can allow for a better heat transfer than traditional systems. The particles can be removed using a cyclone separator, from which they can be recirculated. The main difference between fluidized bed systems and circulating fluidized bed is the gas vortex created with the gasifier and the separator; this keeps solids in a long path of high temperature that will help to keep the process efficient. The fluidized nature inside of the reactor consists of the feed entering the reactor and the air/oxygen flow that keeps this material suspended in air, much like fluids.