Ammonia From Electrolytic Hydrogen

The process generates one volume of oxygen per two volumes of hydrogen or about 0.7 tonne of 02/tonne of NH3 thus, a credit for byproduct oxygen can be taken if there is a use for it. For example, the oxygen can be used in an iron and steel industry. A small additional amount of oxygen would be available from the air separation unit. Another potential byproduct is heavy water 

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Since the electrolytic process does not produce CO2, ammonia cannot be used to make urea unless CO2 is available from another source. It can be used to make ammonium salts (sulfates, phosphates, or nitrates), or ammonia can be applied to the soil directly either in the anhydrous form or in aqueous solution. 

The cost of ammonia production by the electrolytic process is not greatly dependent on plant size, but, of course, it is strongly dependent on the cost of electricity, Thus, if low-cost electricity is available, the electrolytic plant would be competitive with plants using other processes, particularly for small plants. 

A particular advantage in developing countries would be the fact that ammonia production from electrolytic 

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Non-aqueous solvents should be purified by careful distillation, special care being taken to eliminate all traces of moisture. Not only arc conductances in water appreciably different from those in non-aqueous media, but in certain cases, particularly if the electrolytic solution contains hydrogen, hydroxyl or alkoxyl ions, small quantities of water have a very considerable effect on the conductance. Precautions should thus be taken to prevent access of water, as well as of carbon dioxide and ammonia from the atmosphere. 

An acetylene may be reduced to an olefin by sodium in liquid ammonia, ° by electrolytic reduction at a spongy nickel cathode, or by partial hydrogenation over metal catalysts. Catalysts for the hydrogenation include nickel, ° iron, colloidal palladium, and palladium on barium sulfate or calcium carbonate. Pure trans olefins are obtained from dialkylacetylenes by reduction with sodium in liquid ammonia. The yields ate better than 90%. Catalytic hydrogenation leads to mixtures of cis and trans olefins in which the cis isomers predominate. ° Mono- and di-arylacetylenes have also been reduced. ... 

Of this capacity of 114 tons of ammonia daily, 65 tons or 57 per cent is for operation On water-gas hydrogen, 37 tons or 32 per cent is for operation on hydrogen, a by-product of other chemical industries, while only 12 tons or less than ii per cent is for operation on electrolytic hydrogen. Of the operating rate of 80 tons per day, only 3.7 per cent is on hydrogen from the electrolysis of water, while 70 per cent is on water-gas hydrogen and over 26 per cent on by-product hydrogen. 

It was tested in several small 3 to 10 ton per day plants but was never operated intact on a large scale commercial basis. Instead the large commercial units became adaptations of the Haber process, the Cassale Process, or the Claude Process for ammonia synthesis. The American Process was originally described as using electrolytic hydrogen. This was much too expensive for commercial use in America at that time. Instead hydrogen was obtained from the reaction of steam with coal or later from the... 

Important examples of chemical equilibrium systems include (1) the Haber process for the manufacture of ammonia from hydrogen gas and nitrogen gas, (2) the ionization of weak electrolytes in water, and (3) the ionization and dissolution of ionic solids in saturated solutions. 

Hydroxylamine is derived from ammonia by replacing one hydrogen atom by a hydroxyl group. It is prepared by the electrolytic reduction of nitric acid, using a lead cathode ... 

Hydrogen Liquefaction. Hydrogen can be produced from caustic—chlorine electrolytic cells, by decomposition of ammonia or methanol, or by steam—methane reforming. Hydrogen recovered by these methods must be further purified prior to Hquefaction. This is generally achieved by utilizing pressure swing adsorption methods whereby impurities are adsorbed on a soHd adsorbent. 

As world deposits of petroleum and coal are exhausted, new sources of hydrogen will have to be developed for use as a fuel and in the production of ammonia for fertilizer. At present, most hydrogen gas is produced from hydrocarbons, but hydrogen gas can also be generated by the electrolysis of water. Figure 19-23 shows an electrolytic cell set up to decompose water. Two platinum electrodes are dipped in a dilute solution of sulfuric acid. The cell requires just one compartment because hydrogen and oxygen escape from the cell much more rapidly than they react with each other. 

Hexamethylenediamine (HMDA), a monomer for the synthesis of polyamide-6,6, is produced by catalytic hydrogenation of adiponitrile. Three processes, each based on a different reactant, produce the latter coimnercially. The original Du Pont process, still used in a few plants, starts with adipic acid made from cyclohexane adipic acid then reacts with ammonia to yield the dinitrile. This process has been replaced in many plants by the catalytic hydrocyanation of butadiene. A third route to adiponitrile is the electrolytic dimerization of acrylonitrile, the latter produced by the ammoxidation of propene. 

Many of the undesirable substances present in gaseous or liquid streams form volatile weak electrolytes in aqueous solution. These compounds include ammonia, hydrogen sulfide, carbon dioxide and sulfur dioxide. The design and analysis of separation processes involving aqueous solutions of these materials require accurate representation of the phase equilibria between the solution and the vapor phase. Relatively few studies of these types of systems have been published concerning solutions of weak electrolytes. This paper will review the methods that have been used for such solutions and, as an example, consider the alkanolamine solutions used for the removal of the acid gases (H2S and C02) from gas streams. 

The effect of concentration of free (molecular) ammonia on the activity of the electrolyte was derived mainly from two 80 C data points of Miles and Wilson having 16 to 17 molal free ammonia concentration. Data points below 0.2 ionic strength were fitted by application of Kielland s estimation of ionic activity coefficients(6 2). Details are presented elsewhere(45), together with graphs giving partial pressures of ammonia and hydrogen sulfide for temperatures from 80 to 260 F over a range of liquid concentration. 

The solubility of gaseous weak electrolytes in aqueous solutions is encountered in many chemical and petrochemical processes. In comparison to vapory-liquid equilibria in non reacting systems the solubility of gaseous weak electrolytes like ammonia, carbondioxide, hydrogen sulfide and sulfur dioxide in water results not only from physical (vapor-liquid) equilibrium but also from chemical equilibrium in the liquid phase. 

Abstraction of a hydrogen atom from the solvent HS [Eq. (66)] makes it desirable to run the reaction in a solvent that is a poor hydrogen-atom donor liquid ammonia is a preferred solvent. Inorganic salts, such as potassium iodide or bromide, may be employed as supporting electrolyte in the SRN1 reaction in NH3. 

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