Hydrogen production hy steam-iron process

The steam-iron process is one of the oldest methods of producing hydrogen. It is a cyclic process for water cleavage, whereby coal is consumed. Coal i s gassified to a lean reducing gas, containing carbon monoxide and hydrogen . This gas reacts with iron oxides (haematite Fe2O3, magnetite Fe3O4, wuest ite FeO) to produce a reduced form of iron oxide (wuestite FeO, iron Fe). T he reduced iron oxide is re-oxidised with steam to form magnetite and hydro gen. After studies concerning theoretical limitations, the subsequent pract ical realisation by construction of a suitable laboratory prototype reactor was performed. Further, the investigation and optimisation of process vari ables, accompanied by respective chemical analyses, and finally the simulat ion of the whole process and the design of a demonstration plant for electr icity generation system in the range of 10 MW were carried out. The resulti ng overall efficiency (heat and electricity) of the respective power plant was calculated as 35% and the electrical efficiency at about 25%. The opera tion of the small scale "Sponge Iron Reactor" (SIR) showed that the hydroge n produced is sufficiently pure for use in any kind of fuel cell (CO < 10 p pm). (C) 2000 Elsevier Science S.A. All rights reserved.