Synthesis of ammonia at atmospheric pressure with the use of solid state proton conductors

Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in a solid state proton-conducting cell reactor. Two types of reactors were used, one double-chamber and one single-chamber cell. In the double-chambe r cell, hydrogen flowed over the anode and was converted into protons that were transported through the solid electrolyte and reached the cathode (Pd) over which nitrogen was passing. At 570 degrees C, nearly 80% of the elect rochemically supplied hydrogen was converted into ammonia. In the single-ch amber cell, hydrogen and nitrogen were fed in together and the solid electr olyte cell was suspended in the gaseous stream. At 750 degrees C, a NEMCA e ffect was observed but the enhancement was not very strong (Lambda < 2). Th is novel process eliminates the thermodynamic requirements on the temperatu re and pressure of operation of conventional catalytic reactors. (C) 2000 A cademic Press.