Hydrogen production by steam--iron process

摘要

The steam--iron process is one of the oldest methods of producing hydrogen. lt is a cyclic process for water cleavage, whereby coal is consumed. Coal is gassified to a lean reducing gas, containing carbon monoxide and hydrogen. This gas reacts with iron oxides (haematite Fe_2O_3, magnetite Fe_3O_4, wuestite FeO) to produce a reduced form of iron oxide (wuestite FeO, iron Fe). The reduced iron oxide is re-oxidised with steam to form magnetite and hydrogen. After studies concerning theoretical lindtations, the subsequent practical realisation by construction of a suitable laboratory prototype reactor was performed. Further, the investigation and optimisation of process variables, accompanied by respective chemical analyses, and finally the simulation of the whole process and the design of a demonstration plant for electricity generation system in the range of l0 MW were carried out. The resulting overall efficiency (heat and electricity) of the respective power plant was calculated as 35/100 and the electrical efficiency at about 25/100. The operation of the small scale "Sponge Iron Reactor" (SIR) showed that the hydrogen produced is sufficiently pure for use in any kind of fuel cell (CO < l0