Chlorine processing discharge pressure

The two-phase process stream goes to a receiver that also serves as a phase separator. The liquefied chlorine leaves through a bottom connection. The uncondensed gas, containing some of the chlorine along with the noncondensable impurities, goes overhead. A valve on the outlet line maintains the desired pressure on the gas in the liquefier and also serves to control the discharge pressure of the chlorine compressor. The combination of the pressure and temperature on the process side of the liquefier determines the extent to which the chlorine can condense (see Achievable Degree of Liquefaction, below). 

Uninsulated tanks have a maximum gaseous discharge rate of ca. 2 t/h. The chlorine gas can be used only for low-pressure chlorination processes and at low rates. This method increases the risk of concentrating nitrogen trichloride and other nonvolatile residues in the liquid phase within the tank. In all other circumstances, the liquid chlorine should be transferred into a fixed storage vessel and then vaporized in a special installation. 

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