Replacements to CFCs Essay -- CFC Environment Geology

Missing Chart What do CFCs do? CFCs are commonly used as refrigerants, solvents in industrial cleaning applications, and as aerosol propellants. Why are CFCs being replaced? When CFCs work their way up into the stratosphere, UV radiation from the Sun can break the molecule down, and release a chlorine atom. This chlorine atom then interacts with an ozone molecule (ozone is vital to the Earth's system in that it protects the surface from harmful UV rays). This interaction results in the destruction of ozone and the eventual release of the chlorine atom to break apart another ozone. It has been estimated that one chlorine atom can dismantle about 100,000 ozone molecules. Ozone's importance and the direct threat to it by CFCs, are the reasons behind the replacement of the chemicals. One thing to notice from the chart is the extremely high ODP for the Halon compounds. These compunds (as can be seen from their formulas) contain a bromine atom that can destroy more ozone when compared to a chlorine. This occurs because it takes longer for a bromine atom to be taken out of the stratusphere. Halons were used in foam blowing apparatuses for fire-retarding systems, but were phased out along with CFCs. Innovative chemical companies With the advent of the Montreal Protocol and other legislation to reduce the production and use of CFCs, companies have increased research and development of replacement system and/or chemicals. The companies that have produced proven products for cleaning, refrigeration, and propellant use are 3M and Dupont. Their products Dupont is a world renowned company whose major contributions include chemicals. On the order of CFC replacement, Dupont has developed hydrofluo... ...iverging nozzle where it is accelerated to supersonic speeds. The supersonic gas-liquid stream is directed onto components that require cleaning or cleanliness verification. The velocity imparted to the water by the gas flow gives it sufficient momentum at impact to remove contaminants on the surface of the component being cleaned or verified while simultaneously dissolving the contaminant into the water, which can be captured for cleanliness verification. The flow parameters for the gas-liquid nozzle can be set so virtually any gas and liquid can be used for a desired flow and mixing ratio. In addition, the size and number of nozzles are adjustable. This adjustability makes it possible to create sizes ranging from small handheld cleaning nozzles to very large multiple-nozzle configurations. Unfortunately, the cost and maintenance required for such a system is high.