Chlorine gas distribution

The fire and explosion hazards of chlorine-containing systems have been reviewed [1,3]. A rail tanker of chlorine was being emptied to a chlorine gas distribution network... 

In nothern climates, where ambient temperatures can fall below those required to liquefy chlorine at rather modest pressures, it is necessary to provide means for maintaining the temperatures in chlorine-gas distribution lines above the liquefaction point. This can be done by tracing or wrapping the lines with heating tape, using steam lines, and insulating the pipes. These precautions are especially important in organic process plants, which... 

Falconer, R. L., and T. F. Bidleman, Vapor Pressures and Predicted Particle Gas Distributions of Polychlorinated Biphenyl Congeners as Functions of Temperature and Ortho-Chlorine Substitution, Atmos. Environ., 28, 547-554 (1994). 

The generator and associated eductor and chlorine dioxide distribution pipework system should be well designed, with no potential for free gas to accumulate, and should be located in a protected area that has good ventilation. 

Falconer, R.L. and T.F. Bidleman. 1994. Vapor pressures and predicted particle/gas distributions of polychlorinated biphenyl congeners as functions of temperature and ortho-chlorine substitution. Atmos. Environ. 28 547-554. 

For positive identifications by GC/MS, the full mass spectrum of a tentatively identified component was compared to the mass spectrum of an authentic sample. If the spectra were identical, within experimental error, and if the gas chromatographic retention times of standard and unknown components on a 30-meter SE-54 fused silica capillary column agreed within two seconds, the identification was considered positive. When the amount of material present was insufficient for detection using full scan GC/MS techniques, the more sensitive single and multiple ion monitoring techniques were employed. Confirmation in these cases consisted of coincidences of retention times of mass chromatograms of the unknown and of the authentic sample. For chlorinated materials, the molecular ions contained additional information about the chlorine isotope distribution. Confirmation in those cases included the correct isotope... 

The apparatus for the chlorination of titanium raw stock in a fluidised layer is a cylindrical shaft lined with thick silica brick. There are several shelves with gas distribution grates located one above another for better chlorine consumption and titanium extraction. The parent mixture is loaded onto the top shelf where it is partially chlorinated with unreacted chlorine coming from below and is sent onto the next shelf through a pipe. The most intensive chlorination occurs on the lower shelf. 

Chlorine gas is used to manufacture polyvinyl chloride products, such as these pipes for water distribution. 

Internal mixing of electrolytes is driven by gas lift. Feed headers run the full width of the electrodes, giving even distribution of electrolyte flows. Internal baffles complete the process by preventing channeling of the gas flow. One intent of these design features is to permit controlled acid injection into the brine in order to limit the oxygen content of the chlorine gas, without the need for extensive recirculation devices. Internal circulation is promoted by the use of a split baffle. 

Most chlor-alkali plants use water in a closed circuit to remove waste heat from the process. The heat is then rejected into the atmosphere by cooling the water itself by direct or indirect contact with air. Dry systems using indirect contact are useful in some situations, but the typical chlor-alkali plant uses direct contact. The nearly universal choice for this operation is the cooling tower, where heat transfer and mass transfer occur simultaneously by direct contact between phases. Sections 9.1.3.2 and 3 discuss these transfer processes in connection with the cooling of chlorine gas. The effectiveness of a cooling tower depends on the distribution of water and the means used to promote contact between the water and the air. The internal arrangements of a typical unit are discussed below. 

Aeration. Water is drawn from the bottom of the sand filters and is aerated by spraying. The purpose of this process is to remove objectionable odors and tastes. Disinfection. In the final stage chlorine gas is injected into the water to kill harmful bacteria before the water is distributed to the public. Ozone is also used to disinfect water. In emergencies, water may be disinfected by simply boiling it for a few minutes. 

As the traditional regeneration choice, the chlorine reaction is rapid, positive, and easily controlled. Liquefied chlorine gas has been generally available, and standardized commercial addition systems have been available. Recently, pressure on chlorine distribution and use due to safety and environmental regnlations have made availability and implementation more expensive and difficult. It is significant that the reaction simplicity indicates that all etched copper is converted directly to cupric chloride (combination of Eqs. 34.3 and 34.6).Thus, there is no effect on water or acid balances from the etching reaction itself. 

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