Refrigerants ozone depletion

Production of hydrogen fluoride from reaction of Cap2 with sulfuric acid is the largest user of fluorspar and accounts for approximately 60—65% of total U.S. consumption. The principal uses of hydrogen fluoride are ia the manufacture of aluminum fluoride and synthetic cryoHte for the Hall aluminum process and fluoropolymers and chlorofluorocarbons that are used as refrigerants, solvents, aerosols (qv), and ia plastics. Because of the concern that chlorofluorocarbons cause upper atmosphere ozone depletion, these compounds are being replaced by hydrochlorofluorocarbons and hydrofluorocarbons. 

A leader in the refrigerants industry, we manufacture and supply customers with economical chlorofluorocarbon (CFC) replacements and non-ozone depleting hydrofluorocarbon (HFC) refrigerants for automotive, home, commercial and transportation uses. In the Americas and Asia, you can find these products under the Genetron name and in Europe and the Middle East under Honeywell Refrigerants. 

Ozone depleting compounds (ODCs) (other than refrigerants) ... 

Chlororocarbon (CFG) refrigerants are inherently safer with respect to fire, explosion, and acute toxic hazards when compared to alternative refrigerants such as ammonia, propane, and sulfur dioxide. However, they are believed to cause long term environmental damage because of stratospheric ozone depletion. 

Miller, K. B. Matchett, J. M. Purcell, C. W. and Turner, M. H. (1995). Strategies for Managing Ozone-Depleting Refrigerants, Confronting the Future. Columbus, OH Battelle Press. 

Montreal Protocol on Substances that Deplete the Ozone Layer. The phase-out of CFCs began on Jnly 1, 1989, and by 1997, a hydroflnorcarbon, HFC134a, with zero ozone depletion potential, became the dominant refrigerant in the United States. The phase-out of CFCs in developing countries is on a slower schedule. 

Table 1 lA presents tabulations of the safety of important refrigerants, but this list does not include aU available refrigerants. Table 11-5 summarizes a limited list of comparative hazards to life of refrigerant gas and vapor. The current more applicable refrigerants from the m or manufacturers of the CFC and HCFC refrigerants and their azeotropes/ blends/mrxtures are included, but the list excludes the pure hydrocarbons such as propane, chlorinated hydrocarbons such as methyl chloride and others, inorganics, ammonia, carbon dioxide, etc. See Table 11-6. The CFC compounds have a longer and more serious ozone depletion potential than the HCFC compounds, because these decompose at a much lower atmospheric level and have relatively short atmospheric lifetimes therefore, they do less damage to the ozone layer. Table 11-7 summarizes alternate refrigerants of the same classes as discussed previously. Table 11-8 correlates DuPont s SUVA refrigerant numbers to the corresponding ASHRAE numbers.

Much research is being conducted to find alternatives to CFCs with little or no effect on the ozone layer. Among these are HCFC-123 (HCCI2CF3) to replace Freon-11 and HCFC-22 (CHCIF2) to replace Freon-12 in such uses as air conditioning, refrigeration, aerosol, and foam. These compounds have a much lower ozone depletion value compared to Freon-11, which was assigned a value of 1. Ozone depletion values for HCFC-123 and HCFC-22 relative to Freon-11 equals 0.02 and 0.055, respectively. ... 

Ozone Depletion by CFCs and other chemicals, especially from AC and refrigeration systems. 

Many pulp and paper facilities operate industrial process refrigeration units such as chillers for chlorine dioxide plants. For those units that utilize ozone-depleting chemicals, such as chlorofluo-rocarbons (CFCs), facilities are required under Title VI to follow leak repair requirements. 

Haseley [2.4] differentiates between two categories of refrigerants The first group can be exchanged in compressor systems without changing the compressor itself, but changing the injection valves. The second group with no Ozone Depletion Potential (ODP). 

Single-stage chlorine refrigeration system (ammonia/carbon dioxide/chlorine) with no use of ozone-depleting chemicals. 

It is desired to find a replacement for Freon-12 as an alternative refrigerant [Duvedi Achenie (1996)]. The objective is to find replacements that have the same refrigerant related properties as Freon-12 but without the harmfull environmental properties (such as the Ozone depletion potential) - The new refrigerant must absorb heat at temperatures as low as -1.1°C and reject heat at temperatures as high as 313 K. It must also respect the following characteristics ... 

Freon-12, CCI2F2, was used as a coolant in refrigerators until it was suspected to he a cause of ozone depletion. Determine the molecular shape of CCI2F2 and discuss the possibility that the molecule will be a dipole. 

Kayukawa et al. [17] studied the PVT properties of triiluoromethyl methyl ether, because it is a possible refrigerant with zero ozone depletion potential and low global-warming potential. One series of their data is shown in Table 5.6. Calculate Z, the compressibihty factor, and the molar volume in mol m from the given data, and fit the data for Z as a function of 1 /Pm to both a linear and a quadratic equation to see whether a third virial coefficient is warranted by the data. 

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