The main inputs for the HTW process are coal, oxygen and steam. The coal is first ground to small pieces and pre-dried before it is fed into the bottom part of the fluid bed reactor. The steam and the oxygen are fed into the reactor on four different levels, into and above the fluid bed. In the fluid bed the coal reacts with the oxygen and the steam. This reaction takes place at a temperature of around 800◦C and at a pressure of 10 bar. After the reaction in the fluid bed the generated gas enters the hot zone above the fluid bed. At temperatures around 1, 000◦C additional oxygen and steam is added and left over coal particles react with the gases. This way additional gas is produced and by-products like methane and other hydrocarbons are converted to carbon monoxide and hydrogen. The produced gases leave the reactor at the top through the reactor head. At this point the gas is still mixed with a lot of particles. These are filtered out and fed back into the fluid bed with a zyklon filter and a feed back tube.