Ammonia as a refrigerant

The safety aspects of ammonia plants are well documented and there is reason to expect an increase in the use of ammonia as a refrigerant. 

Misguided substitutions such as the introduction of CFCs as a safe substitute for ammonia as a refrigerant were already mentioned in the introduction. The example... 

Nonfluorine CFC substitutes have been considered, but few are fully satisfactory. For example, we could go back 50 years to the use of anhydrous ammonia as a refrigerant, but NH3 is as toxic now as it ever was. Cyclopentane could be used as a foam-blowing agent, but it is less effective than HCFC-141b and besides would contribute to the volatile organic compound load in the troposphere, which is the root cause of ozone pollution (Section 8.3.2). On the other hand, supercritical CO2 is emerging as an alternative to CFCs in various steps in the preparation of fluorocarbon polymers (Section 8.1.3). 

Euro Chlor [54], however, warns against the use of ammonia as a refrigerant when there is any reasonable chance of its contaminating the chlorine. This could lead to the formation of nitrogen trichloride (Section 9.1.11.2A). 

Refrigerant (Ferdinand Carre) French inventor Carre introduces a refrigerator that uses ammonia as a refrigerant. 

Carbon dioxide is used in the manufacture of sodium carbonate by the ammonia-soda process, urea, salicyclic acid (for aspirin), fire extinguishers and aerated water. Lesser amounts are used to transfer heat generated by an atomic reactor to water and so produce steam and electric power, whilst solid carbon dioxide is used as a refrigerant, a mixture of solid carbon dioxide and alcohol providing a good low-temperature bath (195 K) in which reactions can be carried out in the laboratory. 

The facility stores ammonia to supply nearby fertilizer manufacturers. It is transported to the plant by ship, transferred and stored in the tank for transfer as needed. The facility mainly consists of a storage tank, a refrigeration system, a control system, and a pipe connecting the tank with the plants. Ammonia is transported and stored as a refrigerated liquid (-33 C) at atmospheric pressure. 

Nitrogen In the production of ammonia by the Haber process (see p. 176) the ammonia is then used to make nitric acid, which is used in the manufacture of dyes, explosives and fertilisers In liquid form, as a refrigerant As an inert atmosphere for some processes and chemical reactions, because of its unreactive nature for example, empty oil tankers are filled with nitrogen to prevent fires In food packaging to keep the food fresh, for example in crisp packets where it also prevents the crisps being crushed (Figure 11.10)... 

Liquid SO2 has a number of important uses. It has been used as a refrigerant, although ammonia and chlorofluorocarbons have also been used for this purpose. Liquid S02 has been extensively utilized as a nonaqueous solvent (see Chapter 5). Its low electrical conductivity is more likely to be due to the presence of trace amounts of impurities than a very slight degree of ionization. If ionization of liquid SO2 did occur, it could be represented as... 

Ammonia is found in the environment as the result of natural and industrial processes. It is released into the environment by the breakdown of organic wastes, and it is a constituent of the soil, the atmosphere, and bodies of water. Ammonia is also a key intermediate in the nitrogen cycle and is a product of amino acid metabolism (WHO 1986). Anhydrous ammonia is used in the production of nitric acid, explosives, synthetic fibers, and fertilizers (Budavari 1989). It is used as a refrigerant as a corrosion inhibitor in the purification of water supplies in steel production as a catalyst for polymers as a preservative for latex and in the production of nitrocellulose, urea formaldehyde, sulfite cooking liquors, and nitroparaffins (ACGIH 1991 Lewis 1993). Ammonium hydroxide (10-35% ammonia) is a major constituent of many cleaning solutions. Ammonia... 

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