Ammonia is commonly produced by heating nitrogen and hydrogen in the presence of a catalyst by the reaction N.sub.2 +3H.sub.2 .fwdarw.2NH.sub.3. Such catalysts include fused iron oxide, as in the Haber-Bosch and Claud methods, cyano-iron complex salts, as in the Mont Cenis method, and alkali metal-carbon complexes as in the method developed by Tamuri et al. and disclosed in U.S. Pat. No. 3,660,028 issued May 2, 1972.
The above reaction is reversible, contributing to low yields of product, and it is common to get a yield of ammonia of less than 40%. Because of the reversible nature and low productivity thereby caused, various techniques are employed to shift the reaction to the greater production of ammonia.
Commonly, the reaction of nitrogen and hydrogen is carried out at elevated pressure. Because four moles of gas produce two moles of product, the reaction is shifted to higher product formations at high pressures as a result of the Le Chatelier principle of chemical equilibrium. High pressure reactions necessitate suitable equipment and resulting expense.
In addition to high pressure, sorbents have been employed to adsorb the product ammonia, see e.g., U.S. Pat. No. 3,287,068 issued November, 1966 to R. P. Cahn. Sorbents shift the reaction to the ammonia product side by removing the product from the reaction zone and thus driving the reaction to completion. The use of sorbents, however, is disadvantageous not only in that sorbents involve additional expense, but in the fact that a further step may be necessary to remove the product from the sorbent. This can take the form of depressurizing the system in a cyclic pressurizing-depressurizing process or heating the sorbent-ammonia complex to very high temperatures to release the ammonia.
An obvious expense in producing ammonia from hydrogen and nitrogen is the cost of the reactant gases which require a considerable degree of purity, as small amounts of oxygen or carbon monoxide will poison many of the commonly used catalysts. Thus, even nitrogen so freely available, comprising approximately 80% of the atmosphere, is an expense in the nitrogen-hydrogen reaction.
It is desired to produce ammonia utilizing the nitrogen which composes such a large part of the atmosphere without expensive purification procedures. Furthermore, it is desirable to dispense with the need for diatomic hydrogen which cannot be readily found as such on earth and must itself be produced. The most accessible source of hydrogen in nature is water, and it is desirable to utilize water as the hydrogen source. As water vapor exists to some extent in air at all times, it is desirable to utilize atmospheric nitrogen and hydrogen from atmospheric water vapor to produce ammonia.
It is an object of this invention to produce ammonia utilizing atmospheric nitrogen and atmospheric water vapor. It is a further object to produce ammonia at room temperature and atmospheric pressure.
USPTO Backgrounds
USPTO Backgrounds