Refrigerants Halogenated hydrocarbons

SB-18 Use of Refrigerant (Halogenated Hydrocarbons) Recovery Cylinders. Recommends safe practices for those who supply, use, store, or transport recovery cylinders (2 pages). 

Chemical compounds manufactured at petrochemical plants include methanol, formaldehyde, and halogenated hydrocarbons. Formaldehyde is used in the manufacture of plastic resins, including phenolic, urea, and melamine resins. Halogenated hydrocarbons are used in the manufacture of silicone, solvents, refrigerants, and degreasing agents. 

Reclaimed halogenated hydrocarbons can be used as refrigerants, solvents, cleaners, fumigants, and fire retardants. 

The halogen leak tester is widely used in refrigeration applications, but it is sufficiently sensitive for many types of chemical vacuum systems. The apparatus is filled with a halogenated hydrocarbon and the probe of the tester is passed over the suspected area. The gas that is collected by the probe is passed over a hot platinum wire with the resulting formation of positive ions which are collected and measured with a microammeter. 

Refrigerants and aerosol propellants have been gases of abuse. Inhalation of high-concentration halogenated hydrocarbons causes euphoric effects and later... 

Replacing flammable refrigerants by halogenated hydrocarbons that are known to have acceptable environmental effects. 

The contact angle (30, in radians, for water lies between 0.22tt (=40°) and 0.257T (=45°), and for the halogenated hydrocarbons used as refrigerants it is around 0.1947T (=35°). For other pressures, a0 for the reference heat flux q0 = 20000W/m2 at a reference pressure p0 close to the ambient pressure, is first calculated from the equation above. The desired heat transfer coefficient a at pressure p and heat flux q is obtained from (4.98)... 

Chlorinated hydrocarbons, and other halogenated materials containing chlorine, can decompose to more toxic substances when subjected to heat or electromagnetic radiation in the presence of air or moisture [201,586]. The products of decomposition may include chlorine, hydrogen chloride and phosgene, inter alia, and it is clearly important, in view of the widespread commercial uses of the various halogenated hydrocarbons as solvents, refrigerants. 

Aliphatic halogenated hydrocarbons Anaesthetizing irritant to mucous membranes liver damage kidney damage impaired vision loss of consciousness sometimes convulsions, oedema, death some compounds are carcinogenic Effects depend on the nature of the halogen atoms excretion almost exclusively after metabolism Chemical industry solvents refrigeration plant... 

At the time of the first tropospheric measurements of man-made halogenated hydrocarbons in the early 1970s, the quantities of the chlorofluorocarbons in the atmosphere were found to be approximately equal to the total amounts ever manufactured. In 1974 Molina and Rowland (Molina and Rowland, 1974 Rowland and Molina, 1975) realized that chlorofluorocarbons (CFCs), manufactured and used by humans in a variety of technological applications from refrigerants to aerosol spray propellants, have no tropospheric sink and persist in the atmosphere until they diffuse high into the stratosphere where the powerful UV light photolyzes them. The photolysis reactions release a chlorine (Cl) atom, for example, for CFCl, (CFC-11) and CF.CU (CFC-12),... 

The coolant temperature is lowered from 1 to —5 °C in the heat exchanger. The heat is removed by the evaporation of a halogenated hydrocarbon in the refrigerating unit, whose details are not shown in Fig. 9.5. 

REGARDING THE ABSORPTION OF HALOGENATED HYDROCARBONS IN THE GASEOUS PHASE BY MEANS OF ORGANIC SOLVENTS /USED IN ABSORPTION REFRIGERATORS/. 

A GENERALIZED CORRELATION OF LIQUID THERMAL CONDUCTIVITY OF HALOGENATED HYDROCARBON REFRIGERANTS. PAPER NO. 2151. 

The compounds in question are halogenated hydrocarbons, for example, CFCI3 and CF2CI2. These have had widespread use in ordinary life as refrigerants and propellants for spray cans. The compounds are gases or volatile hquids at usual temperatures, so when released they quickly mix with air. In contrast to most organic com-poimds they are very stable, resisting oxidation by O2 for periods of years or decades. Once in the atmosphere, some of the molecttles eventually find their way to the stratosphere, where Cl atoms are liberated by photochemical reactions and react with O3 to destroy it ... 

ELECTRICAL INSULATION MATERIALS Behavior of Electrical Insulation Materials and of Halogenated Hydrocarbon Refrigerants at Temperatures of -100" to -200"F (1) 148 EPOXY RESINS... 

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