Chlorine from membrane electrolysis cells contains some oxygen which might be required to be reduced for specific downstream use. The liquefaction of the compressed chlorine is performed in one or two stages in heat exchangers (condensers). Operating conditions vary with plant layout; the liquefaction ratio is typically in a range from 90% to more than 95%.
The choice of refrigerant in a specific stage of the liquefaction process depends on the pressure of the chlorine. When the pressure is sufficiently high, water can be used as a non-critical indirect refrigerant. A pressure > 8 bar generally enables such water cooling. thyssenkrupp Uhde Chlorine Engineers offers such chlorine liquefaction at higher pressures, which avoids using critical refrigerants and also lowers energy consumption compared with medium or atmospheric pressure liquefaction processes.