Ammonia compressed liquid

Figure 10-10. The Scientific Co. process for producing aniline from phenol (1) fixed-bed reactor, (2) liquid-gas separator, (3) ammonia compression and recycling, (4) drier, (5) fractionator.

A frequent assumption is that pressure has a negligible effect on liquid-phase properties, and that the properties of a compressed liquid are essentially those of the saturated liquid at the same temperature. Estimate the errors when the enthalpy and entropy of liquid ammonia at 270 K. and 1,500 kPa are assumed equal to the enthalpy and entropy of saturated liquid ammonia at 270 K. For saturated liquid ammonia at 270 K, P" = 381 kPa, V1 = 1.551 x 10 3 m3 kg , and p = 2,095 x 10 3 K . 

LIQUID AMMONIA (7664-41-7, anhydrous, compressed gas or cryogenic liquid 1336-21-6, solution in water) Difficult to ignite, but can detonate in confined spaces in fire. Reacts violently with strong oxidizers, acids (nitric, hydrochloric, sulfuric, picric, hydro-bromic, hydrochlorous, etc.). Shock-, temperature-, and pressure-sensitive compounds are formed with antimony, chlorine, germanium compounds, halogens, heavy metals, hydrocarbons, mercury oxide, silver compounds (azides, chlorides, nitrates, oxides). Fire and/or explosions may be caused by contact with acetaldehyde, acrolein, aldehydes, alkylene oxides, amides, antimony, boron, boron halides, boron triiodide, bromine, bromine chloride, chloric acid, chlorine, chlorine monoxide, o-chloronitrobenzene, l-chloro-2,4-dinitrobenzene, chlorosilane, chloromelamine, chromium trioxide, chromylchloride, epichlorohydrin, fluorine, hexachloromelamine, hypochlorites (do not mix ammonia with liquid household... 

AMMONIA (ANHYDROUS) Liquid Ammonia Non-flammable Compressed Gte, III 3 0 ... 

Ammonia is a cheap reactant that can be reasonably, easily stored in a compressed (liquid) form. The main concerns regard safety aspects (ammonia toxicity and risks of explosion) and ammonia slip. To minimize the latter problem it is necessary either to maintain the NH3/NO ratio in the feed below the stoichiometric value or to use a final catalyst layer to selectively oxidize the ammonia that slips from the reactor [16]. The latter solution is of increasing interest to improve the overall efficiency in the conversion of NO together with minimization of the ammonia slip (benefits in terms of reduced impact on the environment as well as minimization of the possible deposit of ammonium-sulfate on the heat exchanger walls downstream from the SCR reactor). 

Liquid ammonia. This can be prepared by compressing ammonia gas. It has a boiling point of 240 K and is an excellent solvent for many inorganic and organic substances as well as for the alkali metals. Liquid ammonia is slightly ionised. ... 

The compressed synthesis gas is dried, mixed with a recycle stream, and introduced into the synthesis reactor after the recycle compressor. The gas mixture is chilled and liquid ammonia is removed from the secondary separator. The vapor is heated and passed into the ammonia converter. The feed is preheated inside the converter prior to entering the catalyst bed. The reaction occurs at 450-600°C over an iron oxide catalyst. The ammonia synthesis reaction between nitrogen, N2, and hydrogen, Hj, is... 

As far as refrigeration is concerned, this system produces ammonia liquid as the refrigerant that is evaporated in the process unit requiring the refrigeration. In principle this is the same operation at the evaporator as if the system were one of compression. The method of removal of the heat of the ammonia vapor and then the reliquelaction are the points of difference between the systems. 

As methyl alcohol freezes in the neighborhood of — 95°C, measurements at a temperature — 70°C would be comparable with water at room temperature at 25°C methyl alcohol is very unlike water, having a compressibility more than 2.5 times as large. Ethyl alcohol and liquid ammonia are likewise unsuitable for comparison with wat er. 

The apparatus shown in Fig. 2 is assembled in a good hood. One liter of liquid ammonia and 0.5 g. of hydrated ferric nitrate are placed in the 2-1. three-necked flask A, which is equipped with a stirrer and a special reflux condenser cooled with Dry Ice. This condenser is attached to a soda-lime tower which is connected to a source of compressed air through the T-tube C. Over a period of about forty-five minutes, 92 g. (4 gram atoms) of clean sodium shavings is added to the liquid ammonia, and the mixture is stirred until the blue color disappears (one to two hours). 

For the concentration of fruit juice by evaporation, it is proposed to use a falling-film evaporator and to incorporate a heat-pump cycle with ammonia as the medium. The ammonia in vapour form enters the evaporator at 312 K and the water is evaporated from the juices at 287 K. The ammonia in the vapour—liquid mixture enters the condenser at 278 K and the vapour then passes to the compressor. It is estimated that the work required to compress the ammonia is 150 kJ/kg of ammonia and that 2.28 kg of ammonia is cycled/kg water evaporated. The following proposals are made for driving the compressor ... 

Compressing ammonia gas under high pressure forces the molecules into close proximity. In a normal gas, the separation between each molecule is generally large - approximately 1000 molecular diameters is a good generalization. By contrast, the separation between the molecules in a condensed phase (solid or liquid) is more likely to be one to two molecular diameters, thereby explaining why the molar volume of a solid or liquid is so much smaller than the molar volume of a gas. 

Although the atmosphere is 78% nitrogen gas (N2), it is not available (i.e., able to be used) to plants or animals except after it has been fixed. Thus, the development of the process for making ammonia from hydrogen and atmospheric nitrogen by Haber was extremely important. The first reaction (1) in Figure 1.4 shows the reaction carried out in the Haber process. This reaction is reversible so ammonia is compressed and cooled, and liquid ammonia is removed from the reaction mixture to drive the reaction to the right. 

---