Molecular sieves ethylene purification with

The polymerization apparatus (see Fig. 3.2) consists of a 11 three-necked flask, fitted with stirrer, thermometer, gas inlet with tap, and gas outlet.On the inlet side the gas stream passes through three wash bottles one as a safety bottle (A), one for the purification of ethylene, filled with 30 ml of petroleum ether (bp 100-140 °C) and 5 ml of diethylaluminum chloride (B),and one filled with molecular sieves 5 A (C).The last of these dries the ethylene further and also serves to trap aluminum hydroxide carried over from B. On the outlet side there are two wash bottles the first is a safety bottle (D), and the second, (E), is filled with 50 ml of dry bis(2-hydroxyethyl) ether (diglycol), and isolates the apparatus from the external atmosphere. 

The gas stream leaving the quench tower mainly consists of ethylene. The gas is compressed in a multistage compressor with intercooUng and then fed to the caustic tower, where CO is absorbed with a sodium hydroxide (NaOH) solution. NaOH in the gas is removed in a water wash section in the tower. The remaining water in the gas stream is removed in a molecular sieve dryer before the gas enters the final purification stage. 

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